Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

35 files changed, 10053 insertions, 0 deletions

diff --git a/tools/objtool/.gitignore b/tools/objtool/.gitignore
new file mode 100644
index 0000000000..4faa4dd72f
--- /dev/null
+++ b/tools/objtool/.gitignore
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0-only
+arch/x86/lib/inat-tables.c
+/objtool
+fixdep
+libsubcmd/
diff --git a/tools/objtool/Build b/tools/objtool/Build
new file mode 100644
index 0000000000..a3cdf8af66
--- /dev/null
+++ b/tools/objtool/Build
@@ -0,0 +1,33 @@
+objtool-y += arch/$(SRCARCH)/
+
+objtool-y += weak.o
+
+objtool-y += check.o
+objtool-y += special.o
+objtool-y += builtin-check.o
+objtool-y += elf.o
+objtool-y += objtool.o
+
+objtool-$(BUILD_ORC) += orc_gen.o
+objtool-$(BUILD_ORC) += orc_dump.o
+
+objtool-y += libstring.o
+objtool-y += libctype.o
+objtool-y += str_error_r.o
+objtool-y += librbtree.o
+
+$(OUTPUT)libstring.o: ../lib/string.c FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,cc_o_c)
+
+$(OUTPUT)libctype.o: ../lib/ctype.c FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,cc_o_c)
+
+$(OUTPUT)str_error_r.o: ../lib/str_error_r.c FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,cc_o_c)
+
+$(OUTPUT)librbtree.o: ../lib/rbtree.c FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,cc_o_c)
diff --git a/tools/objtool/Documentation/objtool.txt b/tools/objtool/Documentation/objtool.txt
new file mode 100644
index 0000000000..fe39c2a8ef
--- /dev/null
+++ b/tools/objtool/Documentation/objtool.txt
@@ -0,0 +1,460 @@
+Objtool
+=======
+
+The kernel CONFIG_OBJTOOL option enables a host tool named 'objtool'
+which runs at compile time.  It can do various validations and
+transformations on .o files.
+
+Objtool has become an integral part of the x86-64 kernel toolchain.  The
+kernel depends on it for a variety of security and performance features
+(and other types of features as well).
+
+
+Features
+--------
+
+Objtool has the following features:
+
+- Stack unwinding metadata validation -- useful for helping to ensure
+  stack traces are reliable for live patching
+
+- ORC unwinder metadata generation -- a faster and more precise
+  alternative to frame pointer based unwinding
+
+- Retpoline validation -- ensures that all indirect calls go through
+  retpoline thunks, for Spectre v2 mitigations
+
+- Retpoline call site annotation -- annotates all retpoline thunk call
+  sites, enabling the kernel to patch them inline, to prevent "thunk
+  funneling" for both security and performance reasons
+
+- Non-instrumentation validation -- validates non-instrumentable
+  ("noinstr") code rules, preventing instrumentation in low-level C
+  entry code
+
+- Static call annotation -- annotates static call sites, enabling the
+  kernel to implement inline static calls, a faster alternative to some
+  indirect branches
+
+- Uaccess validation -- validates uaccess rules for a proper
+  implementation of Supervisor Mode Access Protection (SMAP)
+
+- Straight Line Speculation validation -- validates certain SLS
+  mitigations
+
+- Indirect Branch Tracking validation -- validates Intel CET IBT rules
+  to ensure that all functions referenced by function pointers have
+  corresponding ENDBR instructions
+
+- Indirect Branch Tracking annotation -- annotates unused ENDBR
+  instruction sites, enabling the kernel to "seal" them (replace them
+  with NOPs) to further harden IBT
+
+- Function entry annotation -- annotates function entries, enabling
+  kernel function tracing
+
+- Other toolchain hacks which will go unmentioned at this time...
+
+Each feature can be enabled individually or in combination using the
+objtool cmdline.
+
+
+Objects
+-------
+
+Typically, objtool runs on every translation unit (TU, aka ".o file") in
+the kernel.  If a TU is part of a kernel module, the '--module' option
+is added.
+
+However:
+
+- If noinstr validation is enabled, it also runs on vmlinux.o, with all
+  options removed and '--noinstr' added.
+
+- If IBT or LTO is enabled, it doesn't run on TUs at all.  Instead it
+  runs on vmlinux.o and linked modules, with all options.
+
+In summary:
+
+  A) Legacy mode:
+             TU: objtool [--module] <options>
+        vmlinux: N/A
+         module: N/A
+
+  B) CONFIG_NOINSTR_VALIDATION=y && !(CONFIG_X86_KERNEL_IBT=y || CONFIG_LTO=y):
+             TU: objtool [--module] <options>	// no --noinstr
+        vmlinux: objtool --noinstr		// other options removed
+         module: N/A
+
+  C) CONFIG_X86_KERNEL_IBT=y || CONFIG_LTO=y:
+             TU: N/A
+        vmlinux: objtool --noinstr <options>
+         module: objtool --module --noinstr <options>
+
+
+Stack validation
+----------------
+
+Objtool's stack validation feature analyzes every .o file and ensures
+the validity of its stack metadata.  It enforces a set of rules on asm
+code and C inline assembly code so that stack traces can be reliable.
+
+For each function, it recursively follows all possible code paths and
+validates the correct frame pointer state at each instruction.
+
+It also follows code paths involving special sections, like
+.altinstructions, __jump_table, and __ex_table, which can add
+alternative execution paths to a given instruction (or set of
+instructions).  Similarly, it knows how to follow switch statements, for
+which gcc sometimes uses jump tables.
+
+Here are some of the benefits of validating stack metadata:
+
+a) More reliable stack traces for frame pointer enabled kernels
+
+   Frame pointers are used for debugging purposes.  They allow runtime
+   code and debug tools to be able to walk the stack to determine the
+   chain of function call sites that led to the currently executing
+   code.
+
+   For some architectures, frame pointers are enabled by
+   CONFIG_FRAME_POINTER.  For some other architectures they may be
+   required by the ABI (sometimes referred to as "backchain pointers").
+
+   For C code, gcc automatically generates instructions for setting up
+   frame pointers when the -fno-omit-frame-pointer option is used.
+
+   But for asm code, the frame setup instructions have to be written by
+   hand, which most people don't do.  So the end result is that
+   CONFIG_FRAME_POINTER is honored for C code but not for most asm code.
+
+   For stack traces based on frame pointers to be reliable, all
+   functions which call other functions must first create a stack frame
+   and update the frame pointer.  If a first function doesn't properly
+   create a stack frame before calling a second function, the *caller*
+   of the first function will be skipped on the stack trace.
+
+   For example, consider the following example backtrace with frame
+   pointers enabled:
+
+     [<ffffffff81812584>] dump_stack+0x4b/0x63
+     [<ffffffff812d6dc2>] cmdline_proc_show+0x12/0x30
+     [<ffffffff8127f568>] seq_read+0x108/0x3e0
+     [<ffffffff812cce62>] proc_reg_read+0x42/0x70
+     [<ffffffff81256197>] __vfs_read+0x37/0x100
+     [<ffffffff81256b16>] vfs_read+0x86/0x130
+     [<ffffffff81257898>] SyS_read+0x58/0xd0
+     [<ffffffff8181c1f2>] entry_SYSCALL_64_fastpath+0x12/0x76
+
+   It correctly shows that the caller of cmdline_proc_show() is
+   seq_read().
+
+   If we remove the frame pointer logic from cmdline_proc_show() by
+   replacing the frame pointer related instructions with nops, here's
+   what it looks like instead:
+
+     [<ffffffff81812584>] dump_stack+0x4b/0x63
+     [<ffffffff812d6dc2>] cmdline_proc_show+0x12/0x30
+     [<ffffffff812cce62>] proc_reg_read+0x42/0x70
+     [<ffffffff81256197>] __vfs_read+0x37/0x100
+     [<ffffffff81256b16>] vfs_read+0x86/0x130
+     [<ffffffff81257898>] SyS_read+0x58/0xd0
+     [<ffffffff8181c1f2>] entry_SYSCALL_64_fastpath+0x12/0x76
+
+   Notice that cmdline_proc_show()'s caller, seq_read(), has been
+   skipped.  Instead the stack trace seems to show that
+   cmdline_proc_show() was called by proc_reg_read().
+
+   The benefit of objtool here is that because it ensures that *all*
+   functions honor CONFIG_FRAME_POINTER, no functions will ever[*] be
+   skipped on a stack trace.
+
+   [*] unless an interrupt or exception has occurred at the very
+       beginning of a function before the stack frame has been created,
+       or at the very end of the function after the stack frame has been
+       destroyed.  This is an inherent limitation of frame pointers.
+
+b) ORC (Oops Rewind Capability) unwind table generation
+
+   An alternative to frame pointers and DWARF, ORC unwind data can be
+   used to walk the stack.  Unlike frame pointers, ORC data is out of
+   band.  So it doesn't affect runtime performance and it can be
+   reliable even when interrupts or exceptions are involved.
+
+   For more details, see Documentation/arch/x86/orc-unwinder.rst.
+
+c) Higher live patching compatibility rate
+
+   Livepatch has an optional "consistency model", which is needed for
+   more complex patches.  In order for the consistency model to work,
+   stack traces need to be reliable (or an unreliable condition needs to
+   be detectable).  Objtool makes that possible.
+
+   For more details, see the livepatch documentation in the Linux kernel
+   source tree at Documentation/livepatch/livepatch.rst.
+
+To achieve the validation, objtool enforces the following rules:
+
+1. Each callable function must be annotated as such with the ELF
+   function type.  In asm code, this is typically done using the
+   ENTRY/ENDPROC macros.  If objtool finds a return instruction
+   outside of a function, it flags an error since that usually indicates
+   callable code which should be annotated accordingly.
+
+   This rule is needed so that objtool can properly identify each
+   callable function in order to analyze its stack metadata.
+
+2. Conversely, each section of code which is *not* callable should *not*
+   be annotated as an ELF function.  The ENDPROC macro shouldn't be used
+   in this case.
+
+   This rule is needed so that objtool can ignore non-callable code.
+   Such code doesn't have to follow any of the other rules.
+
+3. Each callable function which calls another function must have the
+   correct frame pointer logic, if required by CONFIG_FRAME_POINTER or
+   the architecture's back chain rules.  This can by done in asm code
+   with the FRAME_BEGIN/FRAME_END macros.
+
+   This rule ensures that frame pointer based stack traces will work as
+   designed.  If function A doesn't create a stack frame before calling
+   function B, the _caller_ of function A will be skipped on the stack
+   trace.
+
+4. Dynamic jumps and jumps to undefined symbols are only allowed if:
+
+   a) the jump is part of a switch statement; or
+
+   b) the jump matches sibling call semantics and the frame pointer has
+      the same value it had on function entry.
+
+   This rule is needed so that objtool can reliably analyze all of a
+   function's code paths.  If a function jumps to code in another file,
+   and it's not a sibling call, objtool has no way to follow the jump
+   because it only analyzes a single file at a time.
+
+5. A callable function may not execute kernel entry/exit instructions.
+   The only code which needs such instructions is kernel entry code,
+   which shouldn't be be in callable functions anyway.
+
+   This rule is just a sanity check to ensure that callable functions
+   return normally.
+
+
+Objtool warnings
+----------------
+
+NOTE: When requesting help with an objtool warning, please recreate with
+OBJTOOL_VERBOSE=1 (e.g., "make OBJTOOL_VERBOSE=1") and send the full
+output, including any disassembly or backtrace below the warning, to the
+objtool maintainers.
+
+For asm files, if you're getting an error which doesn't make sense,
+first make sure that the affected code follows the above rules.
+
+For C files, the common culprits are inline asm statements and calls to
+"noreturn" functions.  See below for more details.
+
+Another possible cause for errors in C code is if the Makefile removes
+-fno-omit-frame-pointer or adds -fomit-frame-pointer to the gcc options.
+
+Here are some examples of common warnings reported by objtool, what
+they mean, and suggestions for how to fix them.  When in doubt, ping
+the objtool maintainers.
+
+
+1. file.o: warning: objtool: func()+0x128: call without frame pointer save/setup
+
+   The func() function made a function call without first saving and/or
+   updating the frame pointer, and CONFIG_FRAME_POINTER is enabled.
+
+   If the error is for an asm file, and func() is indeed a callable
+   function, add proper frame pointer logic using the FRAME_BEGIN and
+   FRAME_END macros.  Otherwise, if it's not a callable function, remove
+   its ELF function annotation by changing ENDPROC to END, and instead
+   use the manual unwind hint macros in asm/unwind_hints.h.
+
+   If it's a GCC-compiled .c file, the error may be because the function
+   uses an inline asm() statement which has a "call" instruction.  An
+   asm() statement with a call instruction must declare the use of the
+   stack pointer in its output operand.  On x86_64, this means adding
+   the ASM_CALL_CONSTRAINT as an output constraint:
+
+     asm volatile("call func" : ASM_CALL_CONSTRAINT);
+
+   Otherwise the stack frame may not get created before the call.
+
+
+2. file.o: warning: objtool: .text+0x53: unreachable instruction
+
+   Objtool couldn't find a code path to reach the instruction.
+
+   If the error is for an asm file, and the instruction is inside (or
+   reachable from) a callable function, the function should be annotated
+   with the ENTRY/ENDPROC macros (ENDPROC is the important one).
+   Otherwise, the code should probably be annotated with the unwind hint
+   macros in asm/unwind_hints.h so objtool and the unwinder can know the
+   stack state associated with the code.
+
+   If you're 100% sure the code won't affect stack traces, or if you're
+   a just a bad person, you can tell objtool to ignore it.  See the
+   "Adding exceptions" section below.
+
+   If it's not actually in a callable function (e.g. kernel entry code),
+   change ENDPROC to END.
+
+3. file.o: warning: objtool: foo+0x48c: bar() is missing a __noreturn annotation
+
+   The call from foo() to bar() doesn't return, but bar() is missing the
+   __noreturn annotation.  NOTE: In addition to annotating the function
+   with __noreturn, please also add it to tools/objtool/noreturns.h.
+
+4. file.o: warning: objtool: func(): can't find starting instruction
+   or
+   file.o: warning: objtool: func()+0x11dd: can't decode instruction
+
+   Does the file have data in a text section?  If so, that can confuse
+   objtool's instruction decoder.  Move the data to a more appropriate
+   section like .data or .rodata.
+
+
+5. file.o: warning: objtool: func()+0x6: unsupported instruction in callable function
+
+   This is a kernel entry/exit instruction like sysenter or iret.  Such
+   instructions aren't allowed in a callable function, and are most
+   likely part of the kernel entry code.  They should usually not have
+   the callable function annotation (ENDPROC) and should always be
+   annotated with the unwind hint macros in asm/unwind_hints.h.
+
+
+6. file.o: warning: objtool: func()+0x26: sibling call from callable instruction with modified stack frame
+
+   This is a dynamic jump or a jump to an undefined symbol.  Objtool
+   assumed it's a sibling call and detected that the frame pointer
+   wasn't first restored to its original state.
+
+   If it's not really a sibling call, you may need to move the
+   destination code to the local file.
+
+   If the instruction is not actually in a callable function (e.g.
+   kernel entry code), change ENDPROC to END and annotate manually with
+   the unwind hint macros in asm/unwind_hints.h.
+
+
+7. file: warning: objtool: func()+0x5c: stack state mismatch
+
+   The instruction's frame pointer state is inconsistent, depending on
+   which execution path was taken to reach the instruction.
+
+   Make sure that, when CONFIG_FRAME_POINTER is enabled, the function
+   pushes and sets up the frame pointer (for x86_64, this means rbp) at
+   the beginning of the function and pops it at the end of the function.
+   Also make sure that no other code in the function touches the frame
+   pointer.
+
+   Another possibility is that the code has some asm or inline asm which
+   does some unusual things to the stack or the frame pointer.  In such
+   cases it's probably appropriate to use the unwind hint macros in
+   asm/unwind_hints.h.
+
+
+8. file.o: warning: objtool: funcA() falls through to next function funcB()
+
+   This means that funcA() doesn't end with a return instruction or an
+   unconditional jump, and that objtool has determined that the function
+   can fall through into the next function.  There could be different
+   reasons for this:
+
+   1) funcA()'s last instruction is a call to a "noreturn" function like
+      panic().  In this case the noreturn function needs to be added to
+      objtool's hard-coded global_noreturns array.  Feel free to bug the
+      objtool maintainer, or you can submit a patch.
+
+   2) funcA() uses the unreachable() annotation in a section of code
+      that is actually reachable.
+
+   3) If funcA() calls an inline function, the object code for funcA()
+      might be corrupt due to a gcc bug.  For more details, see:
+      https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70646
+
+9. file.o: warning: objtool: funcA() call to funcB() with UACCESS enabled
+
+   This means that an unexpected call to a non-whitelisted function exists
+   outside of arch-specific guards.
+   X86: SMAP (stac/clac): __uaccess_begin()/__uaccess_end()
+   ARM: PAN: uaccess_enable()/uaccess_disable()
+
+   These functions should be called to denote a minimal critical section around
+   access to __user variables. See also: https://lwn.net/Articles/517475/
+
+   The intention of the warning is to prevent calls to funcB() from eventually
+   calling schedule(), potentially leaking the AC flags state, and not
+   restoring them correctly.
+
+   It also helps verify that there are no unexpected calls to funcB() which may
+   access user space pages with protections against doing so disabled.
+
+   To fix, either:
+   1) remove explicit calls to funcB() from funcA().
+   2) add the correct guards before and after calls to low level functions like
+      __get_user_size()/__put_user_size().
+   3) add funcB to uaccess_safe_builtin whitelist in tools/objtool/check.c, if
+      funcB obviously does not call schedule(), and is marked notrace (since
+      function tracing inserts additional calls, which is not obvious from the
+      sources).
+
+10. file.o: warning: func()+0x5c: stack layout conflict in alternatives
+
+    This means that in the use of the alternative() or ALTERNATIVE()
+    macro, the code paths have conflicting modifications to the stack.
+    The problem is that there is only one ORC unwind table, which means
+    that the ORC unwind entries must be consistent for all possible
+    instruction boundaries regardless of which code has been patched.
+    This limitation can be overcome by massaging the alternatives with
+    NOPs to shift the stack changes around so they no longer conflict.
+
+11. file.o: warning: unannotated intra-function call
+
+   This warning means that a direct call is done to a destination which
+   is not at the beginning of a function. If this is a legit call, you
+   can remove this warning by putting the ANNOTATE_INTRA_FUNCTION_CALL
+   directive right before the call.
+
+12. file.o: warning: func(): not an indirect call target
+
+   This means that objtool is running with --ibt and a function expected
+   to be an indirect call target is not. In particular, this happens for
+   init_module() or cleanup_module() if a module relies on these special
+   names and does not use module_init() / module_exit() macros to create
+   them.
+
+
+If the error doesn't seem to make sense, it could be a bug in objtool.
+Feel free to ask the objtool maintainer for help.
+
+
+Adding exceptions
+-----------------
+
+If you _really_ need objtool to ignore something, and are 100% sure
+that it won't affect kernel stack traces, you can tell objtool to
+ignore it:
+
+- To skip validation of a function, use the STACK_FRAME_NON_STANDARD
+  macro.
+
+- To skip validation of a file, add
+
+    OBJECT_FILES_NON_STANDARD_filename.o := y
+
+  to the Makefile.
+
+- To skip validation of a directory, add
+
+    OBJECT_FILES_NON_STANDARD := y
+
+  to the Makefile.
+
+NOTE: OBJECT_FILES_NON_STANDARD doesn't work for link time validation of
+vmlinux.o or a linked module.  So it should only be used for files which
+aren't linked into vmlinux or a module.
diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
new file mode 100644
index 0000000000..83b100c1e7
--- /dev/null
+++ b/tools/objtool/Makefile
@@ -0,0 +1,94 @@
+# SPDX-License-Identifier: GPL-2.0
+include ../scripts/Makefile.include
+include ../scripts/Makefile.arch
+
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+endif
+
+LIBSUBCMD_DIR = $(srctree)/tools/lib/subcmd/
+ifneq ($(OUTPUT),)
+  LIBSUBCMD_OUTPUT = $(abspath $(OUTPUT))/libsubcmd
+else
+  LIBSUBCMD_OUTPUT = $(CURDIR)/libsubcmd
+endif
+LIBSUBCMD = $(LIBSUBCMD_OUTPUT)/libsubcmd.a
+
+OBJTOOL    := $(OUTPUT)objtool
+OBJTOOL_IN := $(OBJTOOL)-in.o
+
+LIBELF_FLAGS := $(shell $(HOSTPKG_CONFIG) libelf --cflags 2>/dev/null)
+LIBELF_LIBS  := $(shell $(HOSTPKG_CONFIG) libelf --libs 2>/dev/null || echo -lelf)
+
+all: $(OBJTOOL)
+
+INCLUDES := -I$(srctree)/tools/include \
+	    -I$(srctree)/tools/arch/$(HOSTARCH)/include/uapi \
+	    -I$(srctree)/tools/arch/$(SRCARCH)/include	\
+	    -I$(srctree)/tools/objtool/include \
+	    -I$(srctree)/tools/objtool/arch/$(SRCARCH)/include \
+	    -I$(LIBSUBCMD_OUTPUT)/include
+# Note, EXTRA_WARNINGS here was determined for CC and not HOSTCC, it
+# is passed here to match a legacy behavior.
+WARNINGS := $(EXTRA_WARNINGS) -Wno-switch-default -Wno-switch-enum -Wno-packed -Wno-nested-externs
+OBJTOOL_CFLAGS := -Werror $(WARNINGS) $(KBUILD_HOSTCFLAGS) -g $(INCLUDES) $(LIBELF_FLAGS)
+OBJTOOL_LDFLAGS := $(LIBELF_LIBS) $(LIBSUBCMD) $(KBUILD_HOSTLDFLAGS)
+
+# Allow old libelf to be used:
+elfshdr := $(shell echo '$(pound)include <libelf.h>' | $(HOSTCC) $(OBJTOOL_CFLAGS) -x c -E - | grep elf_getshdr)
+OBJTOOL_CFLAGS += $(if $(elfshdr),,-DLIBELF_USE_DEPRECATED)
+
+# Always want host compilation.
+HOST_OVERRIDES := CC="$(HOSTCC)" LD="$(HOSTLD)" AR="$(HOSTAR)"
+
+AWK = awk
+MKDIR = mkdir
+
+ifeq ($(V),1)
+  Q =
+else
+  Q = @
+endif
+
+BUILD_ORC := n
+
+ifeq ($(SRCARCH),x86)
+	BUILD_ORC := y
+endif
+
+export BUILD_ORC
+export srctree OUTPUT CFLAGS SRCARCH AWK
+include $(srctree)/tools/build/Makefile.include
+
+$(OBJTOOL_IN): fixdep $(LIBSUBCMD) FORCE
+	$(Q)$(CONFIG_SHELL) ./sync-check.sh
+	$(Q)$(MAKE) $(build)=objtool $(HOST_OVERRIDES) CFLAGS="$(OBJTOOL_CFLAGS)" \
+		LDFLAGS="$(OBJTOOL_LDFLAGS)"
+
+
+$(OBJTOOL): $(LIBSUBCMD) $(OBJTOOL_IN)
+	$(QUIET_LINK)$(HOSTCC) $(OBJTOOL_IN) $(OBJTOOL_LDFLAGS) -o $@
+
+
+$(LIBSUBCMD_OUTPUT):
+	$(Q)$(MKDIR) -p $@
+
+$(LIBSUBCMD): fixdep $(LIBSUBCMD_OUTPUT) FORCE
+	$(Q)$(MAKE) -C $(LIBSUBCMD_DIR) O=$(LIBSUBCMD_OUTPUT) \
+		DESTDIR=$(LIBSUBCMD_OUTPUT) prefix= subdir= \
+		$(HOST_OVERRIDES) EXTRA_CFLAGS="$(OBJTOOL_CFLAGS)" \
+		$@ install_headers
+
+$(LIBSUBCMD)-clean:
+	$(call QUIET_CLEAN, libsubcmd)
+	$(Q)$(RM) -r -- $(LIBSUBCMD_OUTPUT)
+
+clean: $(LIBSUBCMD)-clean
+	$(call QUIET_CLEAN, objtool) $(RM) $(OBJTOOL)
+	$(Q)find $(OUTPUT) -name '*.o' -delete -o -name '\.*.cmd' -delete -o -name '\.*.d' -delete
+	$(Q)$(RM) $(OUTPUT)arch/x86/lib/inat-tables.c $(OUTPUT)fixdep
+
+FORCE:
+
+.PHONY: clean FORCE
diff --git a/tools/objtool/arch/powerpc/Build b/tools/objtool/arch/powerpc/Build
new file mode 100644
index 0000000000..d24d5636a5
--- /dev/null
+++ b/tools/objtool/arch/powerpc/Build
@@ -0,0 +1,2 @@
+objtool-y += decode.o
+objtool-y += special.o
diff --git a/tools/objtool/arch/powerpc/decode.c b/tools/objtool/arch/powerpc/decode.c
new file mode 100644
index 0000000000..53b55690f3
--- /dev/null
+++ b/tools/objtool/arch/powerpc/decode.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <objtool/check.h>
+#include <objtool/elf.h>
+#include <objtool/arch.h>
+#include <objtool/warn.h>
+#include <objtool/builtin.h>
+#include <objtool/endianness.h>
+
+int arch_ftrace_match(char *name)
+{
+	return !strcmp(name, "_mcount");
+}
+
+unsigned long arch_dest_reloc_offset(int addend)
+{
+	return addend;
+}
+
+bool arch_callee_saved_reg(unsigned char reg)
+{
+	return false;
+}
+
+int arch_decode_hint_reg(u8 sp_reg, int *base)
+{
+	exit(-1);
+}
+
+const char *arch_nop_insn(int len)
+{
+	exit(-1);
+}
+
+const char *arch_ret_insn(int len)
+{
+	exit(-1);
+}
+
+int arch_decode_instruction(struct objtool_file *file, const struct section *sec,
+			    unsigned long offset, unsigned int maxlen,
+			    struct instruction *insn)
+{
+	unsigned int opcode;
+	enum insn_type typ;
+	unsigned long imm;
+	u32 ins;
+
+	ins = bswap_if_needed(file->elf, *(u32 *)(sec->data->d_buf + offset));
+	opcode = ins >> 26;
+	typ = INSN_OTHER;
+	imm = 0;
+
+	switch (opcode) {
+	case 18: /* b[l][a] */
+		if ((ins & 3) == 1) /* bl */
+			typ = INSN_CALL;
+
+		imm = ins & 0x3fffffc;
+		if (imm & 0x2000000)
+			imm -= 0x4000000;
+		break;
+	}
+
+	if (opcode == 1)
+		insn->len = 8;
+	else
+		insn->len = 4;
+
+	insn->type = typ;
+	insn->immediate = imm;
+
+	return 0;
+}
+
+unsigned long arch_jump_destination(struct instruction *insn)
+{
+	return insn->offset + insn->immediate;
+}
+
+bool arch_pc_relative_reloc(struct reloc *reloc)
+{
+	/*
+	 * The powerpc build only allows certain relocation types, see
+	 * relocs_check.sh, and none of those accepted are PC relative.
+	 */
+	return false;
+}
+
+void arch_initial_func_cfi_state(struct cfi_init_state *state)
+{
+	int i;
+
+	for (i = 0; i < CFI_NUM_REGS; i++) {
+		state->regs[i].base = CFI_UNDEFINED;
+		state->regs[i].offset = 0;
+	}
+
+	/* initial CFA (call frame address) */
+	state->cfa.base = CFI_SP;
+	state->cfa.offset = 0;
+
+	/* initial LR (return address) */
+	state->regs[CFI_RA].base = CFI_CFA;
+	state->regs[CFI_RA].offset = 0;
+}
diff --git a/tools/objtool/arch/powerpc/include/arch/cfi_regs.h b/tools/objtool/arch/powerpc/include/arch/cfi_regs.h
new file mode 100644
index 0000000000..59638ebeaf
--- /dev/null
+++ b/tools/objtool/arch/powerpc/include/arch/cfi_regs.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef _OBJTOOL_CFI_REGS_H
+#define _OBJTOOL_CFI_REGS_H
+
+#define CFI_BP 1
+#define CFI_SP CFI_BP
+#define CFI_RA 32
+#define CFI_NUM_REGS 33
+
+#endif
diff --git a/tools/objtool/arch/powerpc/include/arch/elf.h b/tools/objtool/arch/powerpc/include/arch/elf.h
new file mode 100644
index 0000000000..66814fa280
--- /dev/null
+++ b/tools/objtool/arch/powerpc/include/arch/elf.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _OBJTOOL_ARCH_ELF
+#define _OBJTOOL_ARCH_ELF
+
+#define R_NONE		R_PPC_NONE
+#define R_ABS64		R_PPC64_ADDR64
+#define R_ABS32		R_PPC_ADDR32
+#define R_DATA32	R_PPC_REL32
+#define R_DATA64	R_PPC64_REL64
+#define R_TEXT32	R_PPC_REL32
+#define R_TEXT64	R_PPC64_REL32
+
+#endif /* _OBJTOOL_ARCH_ELF */
diff --git a/tools/objtool/arch/powerpc/include/arch/special.h b/tools/objtool/arch/powerpc/include/arch/special.h
new file mode 100644
index 0000000000..ffef9ada71
--- /dev/null
+++ b/tools/objtool/arch/powerpc/include/arch/special.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _PPC_ARCH_SPECIAL_H
+#define _PPC_ARCH_SPECIAL_H
+
+#define EX_ENTRY_SIZE 8
+#define EX_ORIG_OFFSET 0
+#define EX_NEW_OFFSET 4
+
+#define JUMP_ENTRY_SIZE 16
+#define JUMP_ORIG_OFFSET 0
+#define JUMP_NEW_OFFSET 4
+#define JUMP_KEY_OFFSET 8
+
+#define ALT_ENTRY_SIZE 12
+#define ALT_ORIG_OFFSET 0
+#define ALT_NEW_OFFSET 4
+#define ALT_FEATURE_OFFSET 8
+#define ALT_ORIG_LEN_OFFSET 10
+#define ALT_NEW_LEN_OFFSET 11
+
+#endif /* _PPC_ARCH_SPECIAL_H */
diff --git a/tools/objtool/arch/powerpc/special.c b/tools/objtool/arch/powerpc/special.c
new file mode 100644
index 0000000000..d338681471
--- /dev/null
+++ b/tools/objtool/arch/powerpc/special.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <string.h>
+#include <stdlib.h>
+#include <objtool/special.h>
+#include <objtool/builtin.h>
+
+
+bool arch_support_alt_relocation(struct special_alt *special_alt,
+				 struct instruction *insn,
+				 struct reloc *reloc)
+{
+	exit(-1);
+}
+
+struct reloc *arch_find_switch_table(struct objtool_file *file,
+				    struct instruction *insn)
+{
+	exit(-1);
+}
diff --git a/tools/objtool/arch/x86/Build b/tools/objtool/arch/x86/Build
new file mode 100644
index 0000000000..9f7869b5c5
--- /dev/null
+++ b/tools/objtool/arch/x86/Build
@@ -0,0 +1,13 @@
+objtool-y += special.o
+objtool-y += decode.o
+
+inat_tables_script = ../arch/x86/tools/gen-insn-attr-x86.awk
+inat_tables_maps = ../arch/x86/lib/x86-opcode-map.txt
+
+$(OUTPUT)arch/x86/lib/inat-tables.c: $(inat_tables_script) $(inat_tables_maps)
+	$(call rule_mkdir)
+	$(Q)$(call echo-cmd,gen)$(AWK) -f $(inat_tables_script) $(inat_tables_maps) > $@
+
+$(OUTPUT)arch/x86/decode.o: $(OUTPUT)arch/x86/lib/inat-tables.c
+
+CFLAGS_decode.o += -I$(OUTPUT)arch/x86/lib
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
new file mode 100644
index 0000000000..c0f25d0018
--- /dev/null
+++ b/tools/objtool/arch/x86/decode.c
@@ -0,0 +1,834 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#define unlikely(cond) (cond)
+#include <asm/insn.h>
+#include "../../../arch/x86/lib/inat.c"
+#include "../../../arch/x86/lib/insn.c"
+
+#define CONFIG_64BIT 1
+#include <asm/nops.h>
+
+#include <asm/orc_types.h>
+#include <objtool/check.h>
+#include <objtool/elf.h>
+#include <objtool/arch.h>
+#include <objtool/warn.h>
+#include <objtool/endianness.h>
+#include <objtool/builtin.h>
+#include <arch/elf.h>
+
+int arch_ftrace_match(char *name)
+{
+	return !strcmp(name, "__fentry__");
+}
+
+static int is_x86_64(const struct elf *elf)
+{
+	switch (elf->ehdr.e_machine) {
+	case EM_X86_64:
+		return 1;
+	case EM_386:
+		return 0;
+	default:
+		WARN("unexpected ELF machine type %d", elf->ehdr.e_machine);
+		return -1;
+	}
+}
+
+bool arch_callee_saved_reg(unsigned char reg)
+{
+	switch (reg) {
+	case CFI_BP:
+	case CFI_BX:
+	case CFI_R12:
+	case CFI_R13:
+	case CFI_R14:
+	case CFI_R15:
+		return true;
+
+	case CFI_AX:
+	case CFI_CX:
+	case CFI_DX:
+	case CFI_SI:
+	case CFI_DI:
+	case CFI_SP:
+	case CFI_R8:
+	case CFI_R9:
+	case CFI_R10:
+	case CFI_R11:
+	case CFI_RA:
+	default:
+		return false;
+	}
+}
+
+unsigned long arch_dest_reloc_offset(int addend)
+{
+	return addend + 4;
+}
+
+unsigned long arch_jump_destination(struct instruction *insn)
+{
+	return insn->offset + insn->len + insn->immediate;
+}
+
+bool arch_pc_relative_reloc(struct reloc *reloc)
+{
+	/*
+	 * All relocation types where P (the address of the target)
+	 * is included in the computation.
+	 */
+	switch (reloc_type(reloc)) {
+	case R_X86_64_PC8:
+	case R_X86_64_PC16:
+	case R_X86_64_PC32:
+	case R_X86_64_PC64:
+
+	case R_X86_64_PLT32:
+	case R_X86_64_GOTPC32:
+	case R_X86_64_GOTPCREL:
+		return true;
+
+	default:
+		break;
+	}
+
+	return false;
+}
+
+#define ADD_OP(op) \
+	if (!(op = calloc(1, sizeof(*op)))) \
+		return -1; \
+	else for (*ops_list = op, ops_list = &op->next; op; op = NULL)
+
+/*
+ * Helpers to decode ModRM/SIB:
+ *
+ * r/m| AX  CX  DX  BX |  SP |  BP |  SI  DI |
+ *    | R8  R9 R10 R11 | R12 | R13 | R14 R15 |
+ * Mod+----------------+-----+-----+---------+
+ * 00 |    [r/m]       |[SIB]|[IP+]|  [r/m]  |
+ * 01 |  [r/m + d8]    |[S+d]|   [r/m + d8]  |
+ * 10 |  [r/m + d32]   |[S+D]|   [r/m + d32] |
+ * 11 |                   r/ m               |
+ */
+
+#define mod_is_mem()	(modrm_mod != 3)
+#define mod_is_reg()	(modrm_mod == 3)
+
+#define is_RIP()   ((modrm_rm & 7) == CFI_BP && modrm_mod == 0)
+#define have_SIB() ((modrm_rm & 7) == CFI_SP && mod_is_mem())
+
+#define rm_is(reg) (have_SIB() ? \
+		    sib_base == (reg) && sib_index == CFI_SP : \
+		    modrm_rm == (reg))
+
+#define rm_is_mem(reg)	(mod_is_mem() && !is_RIP() && rm_is(reg))
+#define rm_is_reg(reg)	(mod_is_reg() && modrm_rm == (reg))
+
+static bool has_notrack_prefix(struct insn *insn)
+{
+	int i;
+
+	for (i = 0; i < insn->prefixes.nbytes; i++) {
+		if (insn->prefixes.bytes[i] == 0x3e)
+			return true;
+	}
+
+	return false;
+}
+
+int arch_decode_instruction(struct objtool_file *file, const struct section *sec,
+			    unsigned long offset, unsigned int maxlen,
+			    struct instruction *insn)
+{
+	struct stack_op **ops_list = &insn->stack_ops;
+	const struct elf *elf = file->elf;
+	struct insn ins;
+	int x86_64, ret;
+	unsigned char op1, op2, op3, prefix,
+		      rex = 0, rex_b = 0, rex_r = 0, rex_w = 0, rex_x = 0,
+		      modrm = 0, modrm_mod = 0, modrm_rm = 0, modrm_reg = 0,
+		      sib = 0, /* sib_scale = 0, */ sib_index = 0, sib_base = 0;
+	struct stack_op *op = NULL;
+	struct symbol *sym;
+	u64 imm;
+
+	x86_64 = is_x86_64(elf);
+	if (x86_64 == -1)
+		return -1;
+
+	ret = insn_decode(&ins, sec->data->d_buf + offset, maxlen,
+			  x86_64 ? INSN_MODE_64 : INSN_MODE_32);
+	if (ret < 0) {
+		WARN("can't decode instruction at %s:0x%lx", sec->name, offset);
+		return -1;
+	}
+
+	insn->len = ins.length;
+	insn->type = INSN_OTHER;
+
+	if (ins.vex_prefix.nbytes)
+		return 0;
+
+	prefix = ins.prefixes.bytes[0];
+
+	op1 = ins.opcode.bytes[0];
+	op2 = ins.opcode.bytes[1];
+	op3 = ins.opcode.bytes[2];
+
+	if (ins.rex_prefix.nbytes) {
+		rex = ins.rex_prefix.bytes[0];
+		rex_w = X86_REX_W(rex) >> 3;
+		rex_r = X86_REX_R(rex) >> 2;
+		rex_x = X86_REX_X(rex) >> 1;
+		rex_b = X86_REX_B(rex);
+	}
+
+	if (ins.modrm.nbytes) {
+		modrm = ins.modrm.bytes[0];
+		modrm_mod = X86_MODRM_MOD(modrm);
+		modrm_reg = X86_MODRM_REG(modrm) + 8*rex_r;
+		modrm_rm  = X86_MODRM_RM(modrm)  + 8*rex_b;
+	}
+
+	if (ins.sib.nbytes) {
+		sib = ins.sib.bytes[0];
+		/* sib_scale = X86_SIB_SCALE(sib); */
+		sib_index = X86_SIB_INDEX(sib) + 8*rex_x;
+		sib_base  = X86_SIB_BASE(sib)  + 8*rex_b;
+	}
+
+	switch (op1) {
+
+	case 0x1:
+	case 0x29:
+		if (rex_w && rm_is_reg(CFI_SP)) {
+
+			/* add/sub reg, %rsp */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_ADD;
+				op->src.reg = modrm_reg;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = CFI_SP;
+			}
+		}
+		break;
+
+	case 0x50 ... 0x57:
+
+		/* push reg */
+		ADD_OP(op) {
+			op->src.type = OP_SRC_REG;
+			op->src.reg = (op1 & 0x7) + 8*rex_b;
+			op->dest.type = OP_DEST_PUSH;
+		}
+
+		break;
+
+	case 0x58 ... 0x5f:
+
+		/* pop reg */
+		ADD_OP(op) {
+			op->src.type = OP_SRC_POP;
+			op->dest.type = OP_DEST_REG;
+			op->dest.reg = (op1 & 0x7) + 8*rex_b;
+		}
+
+		break;
+
+	case 0x68:
+	case 0x6a:
+		/* push immediate */
+		ADD_OP(op) {
+			op->src.type = OP_SRC_CONST;
+			op->dest.type = OP_DEST_PUSH;
+		}
+		break;
+
+	case 0x70 ... 0x7f:
+		insn->type = INSN_JUMP_CONDITIONAL;
+		break;
+
+	case 0x80 ... 0x83:
+		/*
+		 * 1000 00sw : mod OP r/m : immediate
+		 *
+		 * s - sign extend immediate
+		 * w - imm8 / imm32
+		 *
+		 * OP: 000 ADD    100 AND
+		 *     001 OR     101 SUB
+		 *     010 ADC    110 XOR
+		 *     011 SBB    111 CMP
+		 */
+
+		/* 64bit only */
+		if (!rex_w)
+			break;
+
+		/* %rsp target only */
+		if (!rm_is_reg(CFI_SP))
+			break;
+
+		imm = ins.immediate.value;
+		if (op1 & 2) { /* sign extend */
+			if (op1 & 1) { /* imm32 */
+				imm <<= 32;
+				imm = (s64)imm >> 32;
+			} else { /* imm8 */
+				imm <<= 56;
+				imm = (s64)imm >> 56;
+			}
+		}
+
+		switch (modrm_reg & 7) {
+		case 5:
+			imm = -imm;
+			/* fallthrough */
+		case 0:
+			/* add/sub imm, %rsp */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_ADD;
+				op->src.reg = CFI_SP;
+				op->src.offset = imm;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = CFI_SP;
+			}
+			break;
+
+		case 4:
+			/* and imm, %rsp */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_AND;
+				op->src.reg = CFI_SP;
+				op->src.offset = ins.immediate.value;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = CFI_SP;
+			}
+			break;
+
+		default:
+			/* WARN ? */
+			break;
+		}
+
+		break;
+
+	case 0x89:
+		if (!rex_w)
+			break;
+
+		if (modrm_reg == CFI_SP) {
+
+			if (mod_is_reg()) {
+				/* mov %rsp, reg */
+				ADD_OP(op) {
+					op->src.type = OP_SRC_REG;
+					op->src.reg = CFI_SP;
+					op->dest.type = OP_DEST_REG;
+					op->dest.reg = modrm_rm;
+				}
+				break;
+
+			} else {
+				/* skip RIP relative displacement */
+				if (is_RIP())
+					break;
+
+				/* skip nontrivial SIB */
+				if (have_SIB()) {
+					modrm_rm = sib_base;
+					if (sib_index != CFI_SP)
+						break;
+				}
+
+				/* mov %rsp, disp(%reg) */
+				ADD_OP(op) {
+					op->src.type = OP_SRC_REG;
+					op->src.reg = CFI_SP;
+					op->dest.type = OP_DEST_REG_INDIRECT;
+					op->dest.reg = modrm_rm;
+					op->dest.offset = ins.displacement.value;
+				}
+				break;
+			}
+
+			break;
+		}
+
+		if (rm_is_reg(CFI_SP)) {
+
+			/* mov reg, %rsp */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG;
+				op->src.reg = modrm_reg;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = CFI_SP;
+			}
+			break;
+		}
+
+		/* fallthrough */
+	case 0x88:
+		if (!rex_w)
+			break;
+
+		if (rm_is_mem(CFI_BP)) {
+
+			/* mov reg, disp(%rbp) */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG;
+				op->src.reg = modrm_reg;
+				op->dest.type = OP_DEST_REG_INDIRECT;
+				op->dest.reg = CFI_BP;
+				op->dest.offset = ins.displacement.value;
+			}
+			break;
+		}
+
+		if (rm_is_mem(CFI_SP)) {
+
+			/* mov reg, disp(%rsp) */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG;
+				op->src.reg = modrm_reg;
+				op->dest.type = OP_DEST_REG_INDIRECT;
+				op->dest.reg = CFI_SP;
+				op->dest.offset = ins.displacement.value;
+			}
+			break;
+		}
+
+		break;
+
+	case 0x8b:
+		if (!rex_w)
+			break;
+
+		if (rm_is_mem(CFI_BP)) {
+
+			/* mov disp(%rbp), reg */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG_INDIRECT;
+				op->src.reg = CFI_BP;
+				op->src.offset = ins.displacement.value;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = modrm_reg;
+			}
+			break;
+		}
+
+		if (rm_is_mem(CFI_SP)) {
+
+			/* mov disp(%rsp), reg */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG_INDIRECT;
+				op->src.reg = CFI_SP;
+				op->src.offset = ins.displacement.value;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = modrm_reg;
+			}
+			break;
+		}
+
+		break;
+
+	case 0x8d:
+		if (mod_is_reg()) {
+			WARN("invalid LEA encoding at %s:0x%lx", sec->name, offset);
+			break;
+		}
+
+		/* skip non 64bit ops */
+		if (!rex_w)
+			break;
+
+		/* skip RIP relative displacement */
+		if (is_RIP())
+			break;
+
+		/* skip nontrivial SIB */
+		if (have_SIB()) {
+			modrm_rm = sib_base;
+			if (sib_index != CFI_SP)
+				break;
+		}
+
+		/* lea disp(%src), %dst */
+		ADD_OP(op) {
+			op->src.offset = ins.displacement.value;
+			if (!op->src.offset) {
+				/* lea (%src), %dst */
+				op->src.type = OP_SRC_REG;
+			} else {
+				/* lea disp(%src), %dst */
+				op->src.type = OP_SRC_ADD;
+			}
+			op->src.reg = modrm_rm;
+			op->dest.type = OP_DEST_REG;
+			op->dest.reg = modrm_reg;
+		}
+		break;
+
+	case 0x8f:
+		/* pop to mem */
+		ADD_OP(op) {
+			op->src.type = OP_SRC_POP;
+			op->dest.type = OP_DEST_MEM;
+		}
+		break;
+
+	case 0x90:
+		insn->type = INSN_NOP;
+		break;
+
+	case 0x9c:
+		/* pushf */
+		ADD_OP(op) {
+			op->src.type = OP_SRC_CONST;
+			op->dest.type = OP_DEST_PUSHF;
+		}
+		break;
+
+	case 0x9d:
+		/* popf */
+		ADD_OP(op) {
+			op->src.type = OP_SRC_POPF;
+			op->dest.type = OP_DEST_MEM;
+		}
+		break;
+
+	case 0x0f:
+
+		if (op2 == 0x01) {
+
+			if (modrm == 0xca)
+				insn->type = INSN_CLAC;
+			else if (modrm == 0xcb)
+				insn->type = INSN_STAC;
+
+		} else if (op2 >= 0x80 && op2 <= 0x8f) {
+
+			insn->type = INSN_JUMP_CONDITIONAL;
+
+		} else if (op2 == 0x05 || op2 == 0x07 || op2 == 0x34 ||
+			   op2 == 0x35) {
+
+			/* sysenter, sysret */
+			insn->type = INSN_CONTEXT_SWITCH;
+
+		} else if (op2 == 0x0b || op2 == 0xb9) {
+
+			/* ud2 */
+			insn->type = INSN_BUG;
+
+		} else if (op2 == 0x0d || op2 == 0x1f) {
+
+			/* nopl/nopw */
+			insn->type = INSN_NOP;
+
+		} else if (op2 == 0x1e) {
+
+			if (prefix == 0xf3 && (modrm == 0xfa || modrm == 0xfb))
+				insn->type = INSN_ENDBR;
+
+
+		} else if (op2 == 0x38 && op3 == 0xf8) {
+			if (ins.prefixes.nbytes == 1 &&
+			    ins.prefixes.bytes[0] == 0xf2) {
+				/* ENQCMD cannot be used in the kernel. */
+				WARN("ENQCMD instruction at %s:%lx", sec->name,
+				     offset);
+			}
+
+		} else if (op2 == 0xa0 || op2 == 0xa8) {
+
+			/* push fs/gs */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_CONST;
+				op->dest.type = OP_DEST_PUSH;
+			}
+
+		} else if (op2 == 0xa1 || op2 == 0xa9) {
+
+			/* pop fs/gs */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_POP;
+				op->dest.type = OP_DEST_MEM;
+			}
+		}
+
+		break;
+
+	case 0xc9:
+		/*
+		 * leave
+		 *
+		 * equivalent to:
+		 * mov bp, sp
+		 * pop bp
+		 */
+		ADD_OP(op) {
+			op->src.type = OP_SRC_REG;
+			op->src.reg = CFI_BP;
+			op->dest.type = OP_DEST_REG;
+			op->dest.reg = CFI_SP;
+		}
+		ADD_OP(op) {
+			op->src.type = OP_SRC_POP;
+			op->dest.type = OP_DEST_REG;
+			op->dest.reg = CFI_BP;
+		}
+		break;
+
+	case 0xcc:
+		/* int3 */
+		insn->type = INSN_TRAP;
+		break;
+
+	case 0xe3:
+		/* jecxz/jrcxz */
+		insn->type = INSN_JUMP_CONDITIONAL;
+		break;
+
+	case 0xe9:
+	case 0xeb:
+		insn->type = INSN_JUMP_UNCONDITIONAL;
+		break;
+
+	case 0xc2:
+	case 0xc3:
+		insn->type = INSN_RETURN;
+		break;
+
+	case 0xc7: /* mov imm, r/m */
+		if (!opts.noinstr)
+			break;
+
+		if (ins.length == 3+4+4 && !strncmp(sec->name, ".init.text", 10)) {
+			struct reloc *immr, *disp;
+			struct symbol *func;
+			int idx;
+
+			immr = find_reloc_by_dest(elf, (void *)sec, offset+3);
+			disp = find_reloc_by_dest(elf, (void *)sec, offset+7);
+
+			if (!immr || strcmp(immr->sym->name, "pv_ops"))
+				break;
+
+			idx = (reloc_addend(immr) + 8) / sizeof(void *);
+
+			func = disp->sym;
+			if (disp->sym->type == STT_SECTION)
+				func = find_symbol_by_offset(disp->sym->sec, reloc_addend(disp));
+			if (!func) {
+				WARN("no func for pv_ops[]");
+				return -1;
+			}
+
+			objtool_pv_add(file, idx, func);
+		}
+
+		break;
+
+	case 0xcf: /* iret */
+		/*
+		 * Handle sync_core(), which has an IRET to self.
+		 * All other IRET are in STT_NONE entry code.
+		 */
+		sym = find_symbol_containing(sec, offset);
+		if (sym && sym->type == STT_FUNC) {
+			ADD_OP(op) {
+				/* add $40, %rsp */
+				op->src.type = OP_SRC_ADD;
+				op->src.reg = CFI_SP;
+				op->src.offset = 5*8;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = CFI_SP;
+			}
+			break;
+		}
+
+		/* fallthrough */
+
+	case 0xca: /* retf */
+	case 0xcb: /* retf */
+		insn->type = INSN_CONTEXT_SWITCH;
+		break;
+
+	case 0xe0: /* loopne */
+	case 0xe1: /* loope */
+	case 0xe2: /* loop */
+		insn->type = INSN_JUMP_CONDITIONAL;
+		break;
+
+	case 0xe8:
+		insn->type = INSN_CALL;
+		/*
+		 * For the impact on the stack, a CALL behaves like
+		 * a PUSH of an immediate value (the return address).
+		 */
+		ADD_OP(op) {
+			op->src.type = OP_SRC_CONST;
+			op->dest.type = OP_DEST_PUSH;
+		}
+		break;
+
+	case 0xfc:
+		insn->type = INSN_CLD;
+		break;
+
+	case 0xfd:
+		insn->type = INSN_STD;
+		break;
+
+	case 0xff:
+		if (modrm_reg == 2 || modrm_reg == 3) {
+
+			insn->type = INSN_CALL_DYNAMIC;
+			if (has_notrack_prefix(&ins))
+				WARN("notrack prefix found at %s:0x%lx", sec->name, offset);
+
+		} else if (modrm_reg == 4) {
+
+			insn->type = INSN_JUMP_DYNAMIC;
+			if (has_notrack_prefix(&ins))
+				WARN("notrack prefix found at %s:0x%lx", sec->name, offset);
+
+		} else if (modrm_reg == 5) {
+
+			/* jmpf */
+			insn->type = INSN_CONTEXT_SWITCH;
+
+		} else if (modrm_reg == 6) {
+
+			/* push from mem */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_CONST;
+				op->dest.type = OP_DEST_PUSH;
+			}
+		}
+
+		break;
+
+	default:
+		break;
+	}
+
+	insn->immediate = ins.immediate.nbytes ? ins.immediate.value : 0;
+
+	return 0;
+}
+
+void arch_initial_func_cfi_state(struct cfi_init_state *state)
+{
+	int i;
+
+	for (i = 0; i < CFI_NUM_REGS; i++) {
+		state->regs[i].base = CFI_UNDEFINED;
+		state->regs[i].offset = 0;
+	}
+
+	/* initial CFA (call frame address) */
+	state->cfa.base = CFI_SP;
+	state->cfa.offset = 8;
+
+	/* initial RA (return address) */
+	state->regs[CFI_RA].base = CFI_CFA;
+	state->regs[CFI_RA].offset = -8;
+}
+
+const char *arch_nop_insn(int len)
+{
+	static const char nops[5][5] = {
+		{ BYTES_NOP1 },
+		{ BYTES_NOP2 },
+		{ BYTES_NOP3 },
+		{ BYTES_NOP4 },
+		{ BYTES_NOP5 },
+	};
+
+	if (len < 1 || len > 5) {
+		WARN("invalid NOP size: %d\n", len);
+		return NULL;
+	}
+
+	return nops[len-1];
+}
+
+#define BYTE_RET	0xC3
+
+const char *arch_ret_insn(int len)
+{
+	static const char ret[5][5] = {
+		{ BYTE_RET },
+		{ BYTE_RET, 0xcc },
+		{ BYTE_RET, 0xcc, BYTES_NOP1 },
+		{ BYTE_RET, 0xcc, BYTES_NOP2 },
+		{ BYTE_RET, 0xcc, BYTES_NOP3 },
+	};
+
+	if (len < 1 || len > 5) {
+		WARN("invalid RET size: %d\n", len);
+		return NULL;
+	}
+
+	return ret[len-1];
+}
+
+int arch_decode_hint_reg(u8 sp_reg, int *base)
+{
+	switch (sp_reg) {
+	case ORC_REG_UNDEFINED:
+		*base = CFI_UNDEFINED;
+		break;
+	case ORC_REG_SP:
+		*base = CFI_SP;
+		break;
+	case ORC_REG_BP:
+		*base = CFI_BP;
+		break;
+	case ORC_REG_SP_INDIRECT:
+		*base = CFI_SP_INDIRECT;
+		break;
+	case ORC_REG_R10:
+		*base = CFI_R10;
+		break;
+	case ORC_REG_R13:
+		*base = CFI_R13;
+		break;
+	case ORC_REG_DI:
+		*base = CFI_DI;
+		break;
+	case ORC_REG_DX:
+		*base = CFI_DX;
+		break;
+	default:
+		return -1;
+	}
+
+	return 0;
+}
+
+bool arch_is_retpoline(struct symbol *sym)
+{
+	return !strncmp(sym->name, "__x86_indirect_", 15);
+}
+
+bool arch_is_rethunk(struct symbol *sym)
+{
+	return !strcmp(sym->name, "__x86_return_thunk");
+}
+
+bool arch_is_embedded_insn(struct symbol *sym)
+{
+	return !strcmp(sym->name, "retbleed_return_thunk") ||
+	       !strcmp(sym->name, "srso_safe_ret");
+}
diff --git a/tools/objtool/arch/x86/include/arch/cfi_regs.h b/tools/objtool/arch/x86/include/arch/cfi_regs.h
new file mode 100644
index 0000000000..0579d22c43
--- /dev/null
+++ b/tools/objtool/arch/x86/include/arch/cfi_regs.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef _OBJTOOL_CFI_REGS_H
+#define _OBJTOOL_CFI_REGS_H
+
+#define CFI_AX			0
+#define CFI_CX			1
+#define CFI_DX			2
+#define CFI_BX			3
+#define CFI_SP			4
+#define CFI_BP			5
+#define CFI_SI			6
+#define CFI_DI			7
+#define CFI_R8			8
+#define CFI_R9			9
+#define CFI_R10			10
+#define CFI_R11			11
+#define CFI_R12			12
+#define CFI_R13			13
+#define CFI_R14			14
+#define CFI_R15			15
+#define CFI_RA			16
+#define CFI_NUM_REGS		17
+
+#endif /* _OBJTOOL_CFI_REGS_H */
diff --git a/tools/objtool/arch/x86/include/arch/elf.h b/tools/objtool/arch/x86/include/arch/elf.h
new file mode 100644
index 0000000000..7131f7f51a
--- /dev/null
+++ b/tools/objtool/arch/x86/include/arch/elf.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _OBJTOOL_ARCH_ELF
+#define _OBJTOOL_ARCH_ELF
+
+#define R_NONE		R_X86_64_NONE
+#define R_ABS32		R_X86_64_32
+#define R_ABS64		R_X86_64_64
+#define R_DATA32	R_X86_64_PC32
+#define R_DATA64	R_X86_64_PC32
+#define R_TEXT32	R_X86_64_PC32
+#define R_TEXT64	R_X86_64_PC32
+
+#endif /* _OBJTOOL_ARCH_ELF */
diff --git a/tools/objtool/arch/x86/include/arch/special.h b/tools/objtool/arch/x86/include/arch/special.h
new file mode 100644
index 0000000000..ca81313529
--- /dev/null
+++ b/tools/objtool/arch/x86/include/arch/special.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _X86_ARCH_SPECIAL_H
+#define _X86_ARCH_SPECIAL_H
+
+#define EX_ENTRY_SIZE		12
+#define EX_ORIG_OFFSET		0
+#define EX_NEW_OFFSET		4
+
+#define JUMP_ENTRY_SIZE		16
+#define JUMP_ORIG_OFFSET	0
+#define JUMP_NEW_OFFSET		4
+#define JUMP_KEY_OFFSET		8
+
+#define ALT_ENTRY_SIZE		14
+#define ALT_ORIG_OFFSET		0
+#define ALT_NEW_OFFSET		4
+#define ALT_FEATURE_OFFSET	8
+#define ALT_ORIG_LEN_OFFSET	12
+#define ALT_NEW_LEN_OFFSET	13
+
+#endif /* _X86_ARCH_SPECIAL_H */
diff --git a/tools/objtool/arch/x86/special.c b/tools/objtool/arch/x86/special.c
new file mode 100644
index 0000000000..29e949579e
--- /dev/null
+++ b/tools/objtool/arch/x86/special.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <string.h>
+
+#include <objtool/special.h>
+#include <objtool/builtin.h>
+
+#define X86_FEATURE_POPCNT (4 * 32 + 23)
+#define X86_FEATURE_SMAP   (9 * 32 + 20)
+
+void arch_handle_alternative(unsigned short feature, struct special_alt *alt)
+{
+	switch (feature) {
+	case X86_FEATURE_SMAP:
+		/*
+		 * If UACCESS validation is enabled; force that alternative;
+		 * otherwise force it the other way.
+		 *
+		 * What we want to avoid is having both the original and the
+		 * alternative code flow at the same time, in that case we can
+		 * find paths that see the STAC but take the NOP instead of
+		 * CLAC and the other way around.
+		 */
+		if (opts.uaccess)
+			alt->skip_orig = true;
+		else
+			alt->skip_alt = true;
+		break;
+	case X86_FEATURE_POPCNT:
+		/*
+		 * It has been requested that we don't validate the !POPCNT
+		 * feature path which is a "very very small percentage of
+		 * machines".
+		 */
+		alt->skip_orig = true;
+		break;
+	default:
+		break;
+	}
+}
+
+bool arch_support_alt_relocation(struct special_alt *special_alt,
+				 struct instruction *insn,
+				 struct reloc *reloc)
+{
+	return true;
+}
+
+/*
+ * There are 3 basic jump table patterns:
+ *
+ * 1. jmpq *[rodata addr](,%reg,8)
+ *
+ *    This is the most common case by far.  It jumps to an address in a simple
+ *    jump table which is stored in .rodata.
+ *
+ * 2. jmpq *[rodata addr](%rip)
+ *
+ *    This is caused by a rare GCC quirk, currently only seen in three driver
+ *    functions in the kernel, only with certain obscure non-distro configs.
+ *
+ *    As part of an optimization, GCC makes a copy of an existing switch jump
+ *    table, modifies it, and then hard-codes the jump (albeit with an indirect
+ *    jump) to use a single entry in the table.  The rest of the jump table and
+ *    some of its jump targets remain as dead code.
+ *
+ *    In such a case we can just crudely ignore all unreachable instruction
+ *    warnings for the entire object file.  Ideally we would just ignore them
+ *    for the function, but that would require redesigning the code quite a
+ *    bit.  And honestly that's just not worth doing: unreachable instruction
+ *    warnings are of questionable value anyway, and this is such a rare issue.
+ *
+ * 3. mov [rodata addr],%reg1
+ *    ... some instructions ...
+ *    jmpq *(%reg1,%reg2,8)
+ *
+ *    This is a fairly uncommon pattern which is new for GCC 6.  As of this
+ *    writing, there are 11 occurrences of it in the allmodconfig kernel.
+ *
+ *    As of GCC 7 there are quite a few more of these and the 'in between' code
+ *    is significant. Esp. with KASAN enabled some of the code between the mov
+ *    and jmpq uses .rodata itself, which can confuse things.
+ *
+ *    TODO: Once we have DWARF CFI and smarter instruction decoding logic,
+ *    ensure the same register is used in the mov and jump instructions.
+ *
+ *    NOTE: RETPOLINE made it harder still to decode dynamic jumps.
+ */
+struct reloc *arch_find_switch_table(struct objtool_file *file,
+				    struct instruction *insn)
+{
+	struct reloc  *text_reloc, *rodata_reloc;
+	struct section *table_sec;
+	unsigned long table_offset;
+
+	/* look for a relocation which references .rodata */
+	text_reloc = find_reloc_by_dest_range(file->elf, insn->sec,
+					      insn->offset, insn->len);
+	if (!text_reloc || text_reloc->sym->type != STT_SECTION ||
+	    !text_reloc->sym->sec->rodata)
+		return NULL;
+
+	table_offset = reloc_addend(text_reloc);
+	table_sec = text_reloc->sym->sec;
+
+	if (reloc_type(text_reloc) == R_X86_64_PC32)
+		table_offset += 4;
+
+	/*
+	 * Make sure the .rodata address isn't associated with a
+	 * symbol.  GCC jump tables are anonymous data.
+	 *
+	 * Also support C jump tables which are in the same format as
+	 * switch jump tables.  For objtool to recognize them, they
+	 * need to be placed in the C_JUMP_TABLE_SECTION section.  They
+	 * have symbols associated with them.
+	 */
+	if (find_symbol_containing(table_sec, table_offset) &&
+	    strcmp(table_sec->name, C_JUMP_TABLE_SECTION))
+		return NULL;
+
+	/*
+	 * Each table entry has a rela associated with it.  The rela
+	 * should reference text in the same function as the original
+	 * instruction.
+	 */
+	rodata_reloc = find_reloc_by_dest(file->elf, table_sec, table_offset);
+	if (!rodata_reloc)
+		return NULL;
+
+	/*
+	 * Use of RIP-relative switch jumps is quite rare, and
+	 * indicates a rare GCC quirk/bug which can leave dead
+	 * code behind.
+	 */
+	if (reloc_type(text_reloc) == R_X86_64_PC32)
+		file->ignore_unreachables = true;
+
+	return rodata_reloc;
+}
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
new file mode 100644
index 0000000000..5e21cfb766
--- /dev/null
+++ b/tools/objtool/builtin-check.c
@@ -0,0 +1,238 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2015-2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#include <subcmd/parse-options.h>
+#include <string.h>
+#include <stdlib.h>
+#include <objtool/builtin.h>
+#include <objtool/objtool.h>
+
+#define ERROR(format, ...)				\
+	fprintf(stderr,					\
+		"error: objtool: " format "\n",		\
+		##__VA_ARGS__)
+
+struct opts opts;
+
+static const char * const check_usage[] = {
+	"objtool <actions> [<options>] file.o",
+	NULL,
+};
+
+static const char * const env_usage[] = {
+	"OBJTOOL_ARGS=\"<options>\"",
+	NULL,
+};
+
+static int parse_dump(const struct option *opt, const char *str, int unset)
+{
+	if (!str || !strcmp(str, "orc")) {
+		opts.dump_orc = true;
+		return 0;
+	}
+
+	return -1;
+}
+
+static int parse_hacks(const struct option *opt, const char *str, int unset)
+{
+	bool found = false;
+
+	/*
+	 * Use strstr() as a lazy method of checking for comma-separated
+	 * options.
+	 *
+	 * No string provided == enable all options.
+	 */
+
+	if (!str || strstr(str, "jump_label")) {
+		opts.hack_jump_label = true;
+		found = true;
+	}
+
+	if (!str || strstr(str, "noinstr")) {
+		opts.hack_noinstr = true;
+		found = true;
+	}
+
+	if (!str || strstr(str, "skylake")) {
+		opts.hack_skylake = true;
+		found = true;
+	}
+
+	return found ? 0 : -1;
+}
+
+static const struct option check_options[] = {
+	OPT_GROUP("Actions:"),
+	OPT_CALLBACK_OPTARG('h', "hacks", NULL, NULL, "jump_label,noinstr,skylake", "patch toolchain bugs/limitations", parse_hacks),
+	OPT_BOOLEAN('i', "ibt", &opts.ibt, "validate and annotate IBT"),
+	OPT_BOOLEAN('m', "mcount", &opts.mcount, "annotate mcount/fentry calls for ftrace"),
+	OPT_BOOLEAN('n', "noinstr", &opts.noinstr, "validate noinstr rules"),
+	OPT_BOOLEAN('o', "orc", &opts.orc, "generate ORC metadata"),
+	OPT_BOOLEAN('r', "retpoline", &opts.retpoline, "validate and annotate retpoline usage"),
+	OPT_BOOLEAN(0,   "rethunk", &opts.rethunk, "validate and annotate rethunk usage"),
+	OPT_BOOLEAN(0,   "unret", &opts.unret, "validate entry unret placement"),
+	OPT_INTEGER(0,   "prefix", &opts.prefix, "generate prefix symbols"),
+	OPT_BOOLEAN('l', "sls", &opts.sls, "validate straight-line-speculation mitigations"),
+	OPT_BOOLEAN('s', "stackval", &opts.stackval, "validate frame pointer rules"),
+	OPT_BOOLEAN('t', "static-call", &opts.static_call, "annotate static calls"),
+	OPT_BOOLEAN('u', "uaccess", &opts.uaccess, "validate uaccess rules for SMAP"),
+	OPT_BOOLEAN(0  , "cfi", &opts.cfi, "annotate kernel control flow integrity (kCFI) function preambles"),
+	OPT_CALLBACK_OPTARG(0, "dump", NULL, NULL, "orc", "dump metadata", parse_dump),
+
+	OPT_GROUP("Options:"),
+	OPT_BOOLEAN(0, "backtrace", &opts.backtrace, "unwind on error"),
+	OPT_BOOLEAN(0, "backup", &opts.backup, "create .orig files before modification"),
+	OPT_BOOLEAN(0, "dry-run", &opts.dryrun, "don't write modifications"),
+	OPT_BOOLEAN(0, "link", &opts.link, "object is a linked object"),
+	OPT_BOOLEAN(0, "module", &opts.module, "object is part of a kernel module"),
+	OPT_BOOLEAN(0, "mnop", &opts.mnop, "nop out mcount call sites"),
+	OPT_BOOLEAN(0, "no-unreachable", &opts.no_unreachable, "skip 'unreachable instruction' warnings"),
+	OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"),
+	OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"),
+	OPT_BOOLEAN('v', "verbose", &opts.verbose, "verbose warnings"),
+
+	OPT_END(),
+};
+
+int cmd_parse_options(int argc, const char **argv, const char * const usage[])
+{
+	const char *envv[16] = { };
+	char *env;
+	int envc;
+
+	env = getenv("OBJTOOL_ARGS");
+	if (env) {
+		envv[0] = "OBJTOOL_ARGS";
+		for (envc = 1; envc < ARRAY_SIZE(envv); ) {
+			envv[envc++] = env;
+			env = strchr(env, ' ');
+			if (!env)
+				break;
+			*env = '\0';
+			env++;
+		}
+
+		parse_options(envc, envv, check_options, env_usage, 0);
+	}
+
+	env = getenv("OBJTOOL_VERBOSE");
+	if (env && !strcmp(env, "1"))
+		opts.verbose = true;
+
+	argc = parse_options(argc, argv, check_options, usage, 0);
+	if (argc != 1)
+		usage_with_options(usage, check_options);
+	return argc;
+}
+
+static bool opts_valid(void)
+{
+	if (opts.hack_jump_label	||
+	    opts.hack_noinstr		||
+	    opts.ibt			||
+	    opts.mcount			||
+	    opts.noinstr		||
+	    opts.orc			||
+	    opts.retpoline		||
+	    opts.rethunk		||
+	    opts.sls			||
+	    opts.stackval		||
+	    opts.static_call		||
+	    opts.uaccess) {
+		if (opts.dump_orc) {
+			ERROR("--dump can't be combined with other options");
+			return false;
+		}
+
+		return true;
+	}
+
+	if (opts.unret && !opts.rethunk) {
+		ERROR("--unret requires --rethunk");
+		return false;
+	}
+
+	if (opts.dump_orc)
+		return true;
+
+	ERROR("At least one command required");
+	return false;
+}
+
+static bool mnop_opts_valid(void)
+{
+	if (opts.mnop && !opts.mcount) {
+		ERROR("--mnop requires --mcount");
+		return false;
+	}
+
+	return true;
+}
+
+static bool link_opts_valid(struct objtool_file *file)
+{
+	if (opts.link)
+		return true;
+
+	if (has_multiple_files(file->elf)) {
+		ERROR("Linked object detected, forcing --link");
+		opts.link = true;
+		return true;
+	}
+
+	if (opts.noinstr) {
+		ERROR("--noinstr requires --link");
+		return false;
+	}
+
+	if (opts.ibt) {
+		ERROR("--ibt requires --link");
+		return false;
+	}
+
+	if (opts.unret) {
+		ERROR("--unret requires --link");
+		return false;
+	}
+
+	return true;
+}
+
+int objtool_run(int argc, const char **argv)
+{
+	const char *objname;
+	struct objtool_file *file;
+	int ret;
+
+	argc = cmd_parse_options(argc, argv, check_usage);
+	objname = argv[0];
+
+	if (!opts_valid())
+		return 1;
+
+	if (opts.dump_orc)
+		return orc_dump(objname);
+
+	file = objtool_open_read(objname);
+	if (!file)
+		return 1;
+
+	if (!mnop_opts_valid())
+		return 1;
+
+	if (!link_opts_valid(file))
+		return 1;
+
+	ret = check(file);
+	if (ret)
+		return ret;
+
+	if (file->elf->changed)
+		return elf_write(file->elf);
+
+	return 0;
+}
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
new file mode 100644
index 0000000000..e308d1ba66
--- /dev/null
+++ b/tools/objtool/check.c
@@ -0,0 +1,4818 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2015-2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#include <string.h>
+#include <stdlib.h>
+#include <inttypes.h>
+#include <sys/mman.h>
+
+#include <objtool/builtin.h>
+#include <objtool/cfi.h>
+#include <objtool/arch.h>
+#include <objtool/check.h>
+#include <objtool/special.h>
+#include <objtool/warn.h>
+#include <objtool/endianness.h>
+
+#include <linux/objtool_types.h>
+#include <linux/hashtable.h>
+#include <linux/kernel.h>
+#include <linux/static_call_types.h>
+
+struct alternative {
+	struct alternative *next;
+	struct instruction *insn;
+	bool skip_orig;
+};
+
+static unsigned long nr_cfi, nr_cfi_reused, nr_cfi_cache;
+
+static struct cfi_init_state initial_func_cfi;
+static struct cfi_state init_cfi;
+static struct cfi_state func_cfi;
+static struct cfi_state force_undefined_cfi;
+
+struct instruction *find_insn(struct objtool_file *file,
+			      struct section *sec, unsigned long offset)
+{
+	struct instruction *insn;
+
+	hash_for_each_possible(file->insn_hash, insn, hash, sec_offset_hash(sec, offset)) {
+		if (insn->sec == sec && insn->offset == offset)
+			return insn;
+	}
+
+	return NULL;
+}
+
+struct instruction *next_insn_same_sec(struct objtool_file *file,
+				       struct instruction *insn)
+{
+	if (insn->idx == INSN_CHUNK_MAX)
+		return find_insn(file, insn->sec, insn->offset + insn->len);
+
+	insn++;
+	if (!insn->len)
+		return NULL;
+
+	return insn;
+}
+
+static struct instruction *next_insn_same_func(struct objtool_file *file,
+					       struct instruction *insn)
+{
+	struct instruction *next = next_insn_same_sec(file, insn);
+	struct symbol *func = insn_func(insn);
+
+	if (!func)
+		return NULL;
+
+	if (next && insn_func(next) == func)
+		return next;
+
+	/* Check if we're already in the subfunction: */
+	if (func == func->cfunc)
+		return NULL;
+
+	/* Move to the subfunction: */
+	return find_insn(file, func->cfunc->sec, func->cfunc->offset);
+}
+
+static struct instruction *prev_insn_same_sec(struct objtool_file *file,
+					      struct instruction *insn)
+{
+	if (insn->idx == 0) {
+		if (insn->prev_len)
+			return find_insn(file, insn->sec, insn->offset - insn->prev_len);
+		return NULL;
+	}
+
+	return insn - 1;
+}
+
+static struct instruction *prev_insn_same_sym(struct objtool_file *file,
+					      struct instruction *insn)
+{
+	struct instruction *prev = prev_insn_same_sec(file, insn);
+
+	if (prev && insn_func(prev) == insn_func(insn))
+		return prev;
+
+	return NULL;
+}
+
+#define for_each_insn(file, insn)					\
+	for (struct section *__sec, *__fake = (struct section *)1;	\
+	     __fake; __fake = NULL)					\
+		for_each_sec(file, __sec)				\
+			sec_for_each_insn(file, __sec, insn)
+
+#define func_for_each_insn(file, func, insn)				\
+	for (insn = find_insn(file, func->sec, func->offset);		\
+	     insn;							\
+	     insn = next_insn_same_func(file, insn))
+
+#define sym_for_each_insn(file, sym, insn)				\
+	for (insn = find_insn(file, sym->sec, sym->offset);		\
+	     insn && insn->offset < sym->offset + sym->len;		\
+	     insn = next_insn_same_sec(file, insn))
+
+#define sym_for_each_insn_continue_reverse(file, sym, insn)		\
+	for (insn = prev_insn_same_sec(file, insn);			\
+	     insn && insn->offset >= sym->offset;			\
+	     insn = prev_insn_same_sec(file, insn))
+
+#define sec_for_each_insn_from(file, insn)				\
+	for (; insn; insn = next_insn_same_sec(file, insn))
+
+#define sec_for_each_insn_continue(file, insn)				\
+	for (insn = next_insn_same_sec(file, insn); insn;		\
+	     insn = next_insn_same_sec(file, insn))
+
+static inline struct symbol *insn_call_dest(struct instruction *insn)
+{
+	if (insn->type == INSN_JUMP_DYNAMIC ||
+	    insn->type == INSN_CALL_DYNAMIC)
+		return NULL;
+
+	return insn->_call_dest;
+}
+
+static inline struct reloc *insn_jump_table(struct instruction *insn)
+{
+	if (insn->type == INSN_JUMP_DYNAMIC ||
+	    insn->type == INSN_CALL_DYNAMIC)
+		return insn->_jump_table;
+
+	return NULL;
+}
+
+static bool is_jump_table_jump(struct instruction *insn)
+{
+	struct alt_group *alt_group = insn->alt_group;
+
+	if (insn_jump_table(insn))
+		return true;
+
+	/* Retpoline alternative for a jump table? */
+	return alt_group && alt_group->orig_group &&
+	       insn_jump_table(alt_group->orig_group->first_insn);
+}
+
+static bool is_sibling_call(struct instruction *insn)
+{
+	/*
+	 * Assume only STT_FUNC calls have jump-tables.
+	 */
+	if (insn_func(insn)) {
+		/* An indirect jump is either a sibling call or a jump to a table. */
+		if (insn->type == INSN_JUMP_DYNAMIC)
+			return !is_jump_table_jump(insn);
+	}
+
+	/* add_jump_destinations() sets insn_call_dest(insn) for sibling calls. */
+	return (is_static_jump(insn) && insn_call_dest(insn));
+}
+
+/*
+ * This checks to see if the given function is a "noreturn" function.
+ *
+ * For global functions which are outside the scope of this object file, we
+ * have to keep a manual list of them.
+ *
+ * For local functions, we have to detect them manually by simply looking for
+ * the lack of a return instruction.
+ */
+static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
+				int recursion)
+{
+	int i;
+	struct instruction *insn;
+	bool empty = true;
+
+#define NORETURN(func) __stringify(func),
+	static const char * const global_noreturns[] = {
+#include "noreturns.h"
+	};
+#undef NORETURN
+
+	if (!func)
+		return false;
+
+	if (func->bind == STB_GLOBAL || func->bind == STB_WEAK)
+		for (i = 0; i < ARRAY_SIZE(global_noreturns); i++)
+			if (!strcmp(func->name, global_noreturns[i]))
+				return true;
+
+	if (func->bind == STB_WEAK)
+		return false;
+
+	if (!func->len)
+		return false;
+
+	insn = find_insn(file, func->sec, func->offset);
+	if (!insn || !insn_func(insn))
+		return false;
+
+	func_for_each_insn(file, func, insn) {
+		empty = false;
+
+		if (insn->type == INSN_RETURN)
+			return false;
+	}
+
+	if (empty)
+		return false;
+
+	/*
+	 * A function can have a sibling call instead of a return.  In that
+	 * case, the function's dead-end status depends on whether the target
+	 * of the sibling call returns.
+	 */
+	func_for_each_insn(file, func, insn) {
+		if (is_sibling_call(insn)) {
+			struct instruction *dest = insn->jump_dest;
+
+			if (!dest)
+				/* sibling call to another file */
+				return false;
+
+			/* local sibling call */
+			if (recursion == 5) {
+				/*
+				 * Infinite recursion: two functions have
+				 * sibling calls to each other.  This is a very
+				 * rare case.  It means they aren't dead ends.
+				 */
+				return false;
+			}
+
+			return __dead_end_function(file, insn_func(dest), recursion+1);
+		}
+	}
+
+	return true;
+}
+
+static bool dead_end_function(struct objtool_file *file, struct symbol *func)
+{
+	return __dead_end_function(file, func, 0);
+}
+
+static void init_cfi_state(struct cfi_state *cfi)
+{
+	int i;
+
+	for (i = 0; i < CFI_NUM_REGS; i++) {
+		cfi->regs[i].base = CFI_UNDEFINED;
+		cfi->vals[i].base = CFI_UNDEFINED;
+	}
+	cfi->cfa.base = CFI_UNDEFINED;
+	cfi->drap_reg = CFI_UNDEFINED;
+	cfi->drap_offset = -1;
+}
+
+static void init_insn_state(struct objtool_file *file, struct insn_state *state,
+			    struct section *sec)
+{
+	memset(state, 0, sizeof(*state));
+	init_cfi_state(&state->cfi);
+
+	/*
+	 * We need the full vmlinux for noinstr validation, otherwise we can
+	 * not correctly determine insn_call_dest(insn)->sec (external symbols
+	 * do not have a section).
+	 */
+	if (opts.link && opts.noinstr && sec)
+		state->noinstr = sec->noinstr;
+}
+
+static struct cfi_state *cfi_alloc(void)
+{
+	struct cfi_state *cfi = calloc(sizeof(struct cfi_state), 1);
+	if (!cfi) {
+		WARN("calloc failed");
+		exit(1);
+	}
+	nr_cfi++;
+	return cfi;
+}
+
+static int cfi_bits;
+static struct hlist_head *cfi_hash;
+
+static inline bool cficmp(struct cfi_state *cfi1, struct cfi_state *cfi2)
+{
+	return memcmp((void *)cfi1 + sizeof(cfi1->hash),
+		      (void *)cfi2 + sizeof(cfi2->hash),
+		      sizeof(struct cfi_state) - sizeof(struct hlist_node));
+}
+
+static inline u32 cfi_key(struct cfi_state *cfi)
+{
+	return jhash((void *)cfi + sizeof(cfi->hash),
+		     sizeof(*cfi) - sizeof(cfi->hash), 0);
+}
+
+static struct cfi_state *cfi_hash_find_or_add(struct cfi_state *cfi)
+{
+	struct hlist_head *head = &cfi_hash[hash_min(cfi_key(cfi), cfi_bits)];
+	struct cfi_state *obj;
+
+	hlist_for_each_entry(obj, head, hash) {
+		if (!cficmp(cfi, obj)) {
+			nr_cfi_cache++;
+			return obj;
+		}
+	}
+
+	obj = cfi_alloc();
+	*obj = *cfi;
+	hlist_add_head(&obj->hash, head);
+
+	return obj;
+}
+
+static void cfi_hash_add(struct cfi_state *cfi)
+{
+	struct hlist_head *head = &cfi_hash[hash_min(cfi_key(cfi), cfi_bits)];
+
+	hlist_add_head(&cfi->hash, head);
+}
+
+static void *cfi_hash_alloc(unsigned long size)
+{
+	cfi_bits = max(10, ilog2(size));
+	cfi_hash = mmap(NULL, sizeof(struct hlist_head) << cfi_bits,
+			PROT_READ|PROT_WRITE,
+			MAP_PRIVATE|MAP_ANON, -1, 0);
+	if (cfi_hash == (void *)-1L) {
+		WARN("mmap fail cfi_hash");
+		cfi_hash = NULL;
+	}  else if (opts.stats) {
+		printf("cfi_bits: %d\n", cfi_bits);
+	}
+
+	return cfi_hash;
+}
+
+static unsigned long nr_insns;
+static unsigned long nr_insns_visited;
+
+/*
+ * Call the arch-specific instruction decoder for all the instructions and add
+ * them to the global instruction list.
+ */
+static int decode_instructions(struct objtool_file *file)
+{
+	struct section *sec;
+	struct symbol *func;
+	unsigned long offset;
+	struct instruction *insn;
+	int ret;
+
+	for_each_sec(file, sec) {
+		struct instruction *insns = NULL;
+		u8 prev_len = 0;
+		u8 idx = 0;
+
+		if (!(sec->sh.sh_flags & SHF_EXECINSTR))
+			continue;
+
+		if (strcmp(sec->name, ".altinstr_replacement") &&
+		    strcmp(sec->name, ".altinstr_aux") &&
+		    strncmp(sec->name, ".discard.", 9))
+			sec->text = true;
+
+		if (!strcmp(sec->name, ".noinstr.text") ||
+		    !strcmp(sec->name, ".entry.text") ||
+		    !strcmp(sec->name, ".cpuidle.text") ||
+		    !strncmp(sec->name, ".text..__x86.", 13))
+			sec->noinstr = true;
+
+		/*
+		 * .init.text code is ran before userspace and thus doesn't
+		 * strictly need retpolines, except for modules which are
+		 * loaded late, they very much do need retpoline in their
+		 * .init.text
+		 */
+		if (!strcmp(sec->name, ".init.text") && !opts.module)
+			sec->init = true;
+
+		for (offset = 0; offset < sec->sh.sh_size; offset += insn->len) {
+			if (!insns || idx == INSN_CHUNK_MAX) {
+				insns = calloc(sizeof(*insn), INSN_CHUNK_SIZE);
+				if (!insns) {
+					WARN("malloc failed");
+					return -1;
+				}
+				idx = 0;
+			} else {
+				idx++;
+			}
+			insn = &insns[idx];
+			insn->idx = idx;
+
+			INIT_LIST_HEAD(&insn->call_node);
+			insn->sec = sec;
+			insn->offset = offset;
+			insn->prev_len = prev_len;
+
+			ret = arch_decode_instruction(file, sec, offset,
+						      sec->sh.sh_size - offset,
+						      insn);
+			if (ret)
+				return ret;
+
+			prev_len = insn->len;
+
+			/*
+			 * By default, "ud2" is a dead end unless otherwise
+			 * annotated, because GCC 7 inserts it for certain
+			 * divide-by-zero cases.
+			 */
+			if (insn->type == INSN_BUG)
+				insn->dead_end = true;
+
+			hash_add(file->insn_hash, &insn->hash, sec_offset_hash(sec, insn->offset));
+			nr_insns++;
+		}
+
+//		printf("%s: last chunk used: %d\n", sec->name, (int)idx);
+
+		sec_for_each_sym(sec, func) {
+			if (func->type != STT_NOTYPE && func->type != STT_FUNC)
+				continue;
+
+			if (func->offset == sec->sh.sh_size) {
+				/* Heuristic: likely an "end" symbol */
+				if (func->type == STT_NOTYPE)
+					continue;
+				WARN("%s(): STT_FUNC at end of section",
+				     func->name);
+				return -1;
+			}
+
+			if (func->embedded_insn || func->alias != func)
+				continue;
+
+			if (!find_insn(file, sec, func->offset)) {
+				WARN("%s(): can't find starting instruction",
+				     func->name);
+				return -1;
+			}
+
+			sym_for_each_insn(file, func, insn) {
+				insn->sym = func;
+				if (func->type == STT_FUNC &&
+				    insn->type == INSN_ENDBR &&
+				    list_empty(&insn->call_node)) {
+					if (insn->offset == func->offset) {
+						list_add_tail(&insn->call_node, &file->endbr_list);
+						file->nr_endbr++;
+					} else {
+						file->nr_endbr_int++;
+					}
+				}
+			}
+		}
+	}
+
+	if (opts.stats)
+		printf("nr_insns: %lu\n", nr_insns);
+
+	return 0;
+}
+
+/*
+ * Read the pv_ops[] .data table to find the static initialized values.
+ */
+static int add_pv_ops(struct objtool_file *file, const char *symname)
+{
+	struct symbol *sym, *func;
+	unsigned long off, end;
+	struct reloc *reloc;
+	int idx;
+
+	sym = find_symbol_by_name(file->elf, symname);
+	if (!sym)
+		return 0;
+
+	off = sym->offset;
+	end = off + sym->len;
+	for (;;) {
+		reloc = find_reloc_by_dest_range(file->elf, sym->sec, off, end - off);
+		if (!reloc)
+			break;
+
+		func = reloc->sym;
+		if (func->type == STT_SECTION)
+			func = find_symbol_by_offset(reloc->sym->sec,
+						     reloc_addend(reloc));
+
+		idx = (reloc_offset(reloc) - sym->offset) / sizeof(unsigned long);
+
+		objtool_pv_add(file, idx, func);
+
+		off = reloc_offset(reloc) + 1;
+		if (off > end)
+			break;
+	}
+
+	return 0;
+}
+
+/*
+ * Allocate and initialize file->pv_ops[].
+ */
+static int init_pv_ops(struct objtool_file *file)
+{
+	static const char *pv_ops_tables[] = {
+		"pv_ops",
+		"xen_cpu_ops",
+		"xen_irq_ops",
+		"xen_mmu_ops",
+		NULL,
+	};
+	const char *pv_ops;
+	struct symbol *sym;
+	int idx, nr;
+
+	if (!opts.noinstr)
+		return 0;
+
+	file->pv_ops = NULL;
+
+	sym = find_symbol_by_name(file->elf, "pv_ops");
+	if (!sym)
+		return 0;
+
+	nr = sym->len / sizeof(unsigned long);
+	file->pv_ops = calloc(sizeof(struct pv_state), nr);
+	if (!file->pv_ops)
+		return -1;
+
+	for (idx = 0; idx < nr; idx++)
+		INIT_LIST_HEAD(&file->pv_ops[idx].targets);
+
+	for (idx = 0; (pv_ops = pv_ops_tables[idx]); idx++)
+		add_pv_ops(file, pv_ops);
+
+	return 0;
+}
+
+static struct instruction *find_last_insn(struct objtool_file *file,
+					  struct section *sec)
+{
+	struct instruction *insn = NULL;
+	unsigned int offset;
+	unsigned int end = (sec->sh.sh_size > 10) ? sec->sh.sh_size - 10 : 0;
+
+	for (offset = sec->sh.sh_size - 1; offset >= end && !insn; offset--)
+		insn = find_insn(file, sec, offset);
+
+	return insn;
+}
+
+/*
+ * Mark "ud2" instructions and manually annotated dead ends.
+ */
+static int add_dead_ends(struct objtool_file *file)
+{
+	struct section *rsec;
+	struct reloc *reloc;
+	struct instruction *insn;
+	s64 addend;
+
+	/*
+	 * Check for manually annotated dead ends.
+	 */
+	rsec = find_section_by_name(file->elf, ".rela.discard.unreachable");
+	if (!rsec)
+		goto reachable;
+
+	for_each_reloc(rsec, reloc) {
+
+		if (reloc->sym->type != STT_SECTION) {
+			WARN("unexpected relocation symbol type in %s", rsec->name);
+			return -1;
+		}
+
+		addend = reloc_addend(reloc);
+
+		insn = find_insn(file, reloc->sym->sec, addend);
+		if (insn)
+			insn = prev_insn_same_sec(file, insn);
+		else if (addend == reloc->sym->sec->sh.sh_size) {
+			insn = find_last_insn(file, reloc->sym->sec);
+			if (!insn) {
+				WARN("can't find unreachable insn at %s+0x%" PRIx64,
+				     reloc->sym->sec->name, addend);
+				return -1;
+			}
+		} else {
+			WARN("can't find unreachable insn at %s+0x%" PRIx64,
+			     reloc->sym->sec->name, addend);
+			return -1;
+		}
+
+		insn->dead_end = true;
+	}
+
+reachable:
+	/*
+	 * These manually annotated reachable checks are needed for GCC 4.4,
+	 * where the Linux unreachable() macro isn't supported.  In that case
+	 * GCC doesn't know the "ud2" is fatal, so it generates code as if it's
+	 * not a dead end.
+	 */
+	rsec = find_section_by_name(file->elf, ".rela.discard.reachable");
+	if (!rsec)
+		return 0;
+
+	for_each_reloc(rsec, reloc) {
+
+		if (reloc->sym->type != STT_SECTION) {
+			WARN("unexpected relocation symbol type in %s", rsec->name);
+			return -1;
+		}
+
+		addend = reloc_addend(reloc);
+
+		insn = find_insn(file, reloc->sym->sec, addend);
+		if (insn)
+			insn = prev_insn_same_sec(file, insn);
+		else if (addend == reloc->sym->sec->sh.sh_size) {
+			insn = find_last_insn(file, reloc->sym->sec);
+			if (!insn) {
+				WARN("can't find reachable insn at %s+0x%" PRIx64,
+				     reloc->sym->sec->name, addend);
+				return -1;
+			}
+		} else {
+			WARN("can't find reachable insn at %s+0x%" PRIx64,
+			     reloc->sym->sec->name, addend);
+			return -1;
+		}
+
+		insn->dead_end = false;
+	}
+
+	return 0;
+}
+
+static int create_static_call_sections(struct objtool_file *file)
+{
+	struct static_call_site *site;
+	struct section *sec;
+	struct instruction *insn;
+	struct symbol *key_sym;
+	char *key_name, *tmp;
+	int idx;
+
+	sec = find_section_by_name(file->elf, ".static_call_sites");
+	if (sec) {
+		INIT_LIST_HEAD(&file->static_call_list);
+		WARN("file already has .static_call_sites section, skipping");
+		return 0;
+	}
+
+	if (list_empty(&file->static_call_list))
+		return 0;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->static_call_list, call_node)
+		idx++;
+
+	sec = elf_create_section_pair(file->elf, ".static_call_sites",
+				      sizeof(*site), idx, idx * 2);
+	if (!sec)
+		return -1;
+
+	/* Allow modules to modify the low bits of static_call_site::key */
+	sec->sh.sh_flags |= SHF_WRITE;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->static_call_list, call_node) {
+
+		/* populate reloc for 'addr' */
+		if (!elf_init_reloc_text_sym(file->elf, sec,
+					     idx * sizeof(*site), idx * 2,
+					     insn->sec, insn->offset))
+			return -1;
+
+		/* find key symbol */
+		key_name = strdup(insn_call_dest(insn)->name);
+		if (!key_name) {
+			perror("strdup");
+			return -1;
+		}
+		if (strncmp(key_name, STATIC_CALL_TRAMP_PREFIX_STR,
+			    STATIC_CALL_TRAMP_PREFIX_LEN)) {
+			WARN("static_call: trampoline name malformed: %s", key_name);
+			free(key_name);
+			return -1;
+		}
+		tmp = key_name + STATIC_CALL_TRAMP_PREFIX_LEN - STATIC_CALL_KEY_PREFIX_LEN;
+		memcpy(tmp, STATIC_CALL_KEY_PREFIX_STR, STATIC_CALL_KEY_PREFIX_LEN);
+
+		key_sym = find_symbol_by_name(file->elf, tmp);
+		if (!key_sym) {
+			if (!opts.module) {
+				WARN("static_call: can't find static_call_key symbol: %s", tmp);
+				free(key_name);
+				return -1;
+			}
+
+			/*
+			 * For modules(), the key might not be exported, which
+			 * means the module can make static calls but isn't
+			 * allowed to change them.
+			 *
+			 * In that case we temporarily set the key to be the
+			 * trampoline address.  This is fixed up in
+			 * static_call_add_module().
+			 */
+			key_sym = insn_call_dest(insn);
+		}
+		free(key_name);
+
+		/* populate reloc for 'key' */
+		if (!elf_init_reloc_data_sym(file->elf, sec,
+					     idx * sizeof(*site) + 4,
+					     (idx * 2) + 1, key_sym,
+					     is_sibling_call(insn) * STATIC_CALL_SITE_TAIL))
+			return -1;
+
+		idx++;
+	}
+
+	return 0;
+}
+
+static int create_retpoline_sites_sections(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct section *sec;
+	int idx;
+
+	sec = find_section_by_name(file->elf, ".retpoline_sites");
+	if (sec) {
+		WARN("file already has .retpoline_sites, skipping");
+		return 0;
+	}
+
+	idx = 0;
+	list_for_each_entry(insn, &file->retpoline_call_list, call_node)
+		idx++;
+
+	if (!idx)
+		return 0;
+
+	sec = elf_create_section_pair(file->elf, ".retpoline_sites",
+				      sizeof(int), idx, idx);
+	if (!sec)
+		return -1;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->retpoline_call_list, call_node) {
+
+		if (!elf_init_reloc_text_sym(file->elf, sec,
+					     idx * sizeof(int), idx,
+					     insn->sec, insn->offset))
+			return -1;
+
+		idx++;
+	}
+
+	return 0;
+}
+
+static int create_return_sites_sections(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct section *sec;
+	int idx;
+
+	sec = find_section_by_name(file->elf, ".return_sites");
+	if (sec) {
+		WARN("file already has .return_sites, skipping");
+		return 0;
+	}
+
+	idx = 0;
+	list_for_each_entry(insn, &file->return_thunk_list, call_node)
+		idx++;
+
+	if (!idx)
+		return 0;
+
+	sec = elf_create_section_pair(file->elf, ".return_sites",
+				      sizeof(int), idx, idx);
+	if (!sec)
+		return -1;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->return_thunk_list, call_node) {
+
+		if (!elf_init_reloc_text_sym(file->elf, sec,
+					     idx * sizeof(int), idx,
+					     insn->sec, insn->offset))
+			return -1;
+
+		idx++;
+	}
+
+	return 0;
+}
+
+static int create_ibt_endbr_seal_sections(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct section *sec;
+	int idx;
+
+	sec = find_section_by_name(file->elf, ".ibt_endbr_seal");
+	if (sec) {
+		WARN("file already has .ibt_endbr_seal, skipping");
+		return 0;
+	}
+
+	idx = 0;
+	list_for_each_entry(insn, &file->endbr_list, call_node)
+		idx++;
+
+	if (opts.stats) {
+		printf("ibt: ENDBR at function start: %d\n", file->nr_endbr);
+		printf("ibt: ENDBR inside functions:  %d\n", file->nr_endbr_int);
+		printf("ibt: superfluous ENDBR:       %d\n", idx);
+	}
+
+	if (!idx)
+		return 0;
+
+	sec = elf_create_section_pair(file->elf, ".ibt_endbr_seal",
+				      sizeof(int), idx, idx);
+	if (!sec)
+		return -1;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->endbr_list, call_node) {
+
+		int *site = (int *)sec->data->d_buf + idx;
+		struct symbol *sym = insn->sym;
+		*site = 0;
+
+		if (opts.module && sym && sym->type == STT_FUNC &&
+		    insn->offset == sym->offset &&
+		    (!strcmp(sym->name, "init_module") ||
+		     !strcmp(sym->name, "cleanup_module")))
+			WARN("%s(): not an indirect call target", sym->name);
+
+		if (!elf_init_reloc_text_sym(file->elf, sec,
+					     idx * sizeof(int), idx,
+					     insn->sec, insn->offset))
+			return -1;
+
+		idx++;
+	}
+
+	return 0;
+}
+
+static int create_cfi_sections(struct objtool_file *file)
+{
+	struct section *sec;
+	struct symbol *sym;
+	int idx;
+
+	sec = find_section_by_name(file->elf, ".cfi_sites");
+	if (sec) {
+		INIT_LIST_HEAD(&file->call_list);
+		WARN("file already has .cfi_sites section, skipping");
+		return 0;
+	}
+
+	idx = 0;
+	for_each_sym(file, sym) {
+		if (sym->type != STT_FUNC)
+			continue;
+
+		if (strncmp(sym->name, "__cfi_", 6))
+			continue;
+
+		idx++;
+	}
+
+	sec = elf_create_section_pair(file->elf, ".cfi_sites",
+				      sizeof(unsigned int), idx, idx);
+	if (!sec)
+		return -1;
+
+	idx = 0;
+	for_each_sym(file, sym) {
+		if (sym->type != STT_FUNC)
+			continue;
+
+		if (strncmp(sym->name, "__cfi_", 6))
+			continue;
+
+		if (!elf_init_reloc_text_sym(file->elf, sec,
+					     idx * sizeof(unsigned int), idx,
+					     sym->sec, sym->offset))
+			return -1;
+
+		idx++;
+	}
+
+	return 0;
+}
+
+static int create_mcount_loc_sections(struct objtool_file *file)
+{
+	size_t addr_size = elf_addr_size(file->elf);
+	struct instruction *insn;
+	struct section *sec;
+	int idx;
+
+	sec = find_section_by_name(file->elf, "__mcount_loc");
+	if (sec) {
+		INIT_LIST_HEAD(&file->mcount_loc_list);
+		WARN("file already has __mcount_loc section, skipping");
+		return 0;
+	}
+
+	if (list_empty(&file->mcount_loc_list))
+		return 0;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->mcount_loc_list, call_node)
+		idx++;
+
+	sec = elf_create_section_pair(file->elf, "__mcount_loc", addr_size,
+				      idx, idx);
+	if (!sec)
+		return -1;
+
+	sec->sh.sh_addralign = addr_size;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->mcount_loc_list, call_node) {
+
+		struct reloc *reloc;
+
+		reloc = elf_init_reloc_text_sym(file->elf, sec, idx * addr_size, idx,
+					       insn->sec, insn->offset);
+		if (!reloc)
+			return -1;
+
+		set_reloc_type(file->elf, reloc, addr_size == 8 ? R_ABS64 : R_ABS32);
+
+		idx++;
+	}
+
+	return 0;
+}
+
+static int create_direct_call_sections(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct section *sec;
+	int idx;
+
+	sec = find_section_by_name(file->elf, ".call_sites");
+	if (sec) {
+		INIT_LIST_HEAD(&file->call_list);
+		WARN("file already has .call_sites section, skipping");
+		return 0;
+	}
+
+	if (list_empty(&file->call_list))
+		return 0;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->call_list, call_node)
+		idx++;
+
+	sec = elf_create_section_pair(file->elf, ".call_sites",
+				      sizeof(unsigned int), idx, idx);
+	if (!sec)
+		return -1;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->call_list, call_node) {
+
+		if (!elf_init_reloc_text_sym(file->elf, sec,
+					     idx * sizeof(unsigned int), idx,
+					     insn->sec, insn->offset))
+			return -1;
+
+		idx++;
+	}
+
+	return 0;
+}
+
+/*
+ * Warnings shouldn't be reported for ignored functions.
+ */
+static void add_ignores(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct section *rsec;
+	struct symbol *func;
+	struct reloc *reloc;
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.func_stack_frame_non_standard");
+	if (!rsec)
+		return;
+
+	for_each_reloc(rsec, reloc) {
+		switch (reloc->sym->type) {
+		case STT_FUNC:
+			func = reloc->sym;
+			break;
+
+		case STT_SECTION:
+			func = find_func_by_offset(reloc->sym->sec, reloc_addend(reloc));
+			if (!func)
+				continue;
+			break;
+
+		default:
+			WARN("unexpected relocation symbol type in %s: %d",
+			     rsec->name, reloc->sym->type);
+			continue;
+		}
+
+		func_for_each_insn(file, func, insn)
+			insn->ignore = true;
+	}
+}
+
+/*
+ * This is a whitelist of functions that is allowed to be called with AC set.
+ * The list is meant to be minimal and only contains compiler instrumentation
+ * ABI and a few functions used to implement *_{to,from}_user() functions.
+ *
+ * These functions must not directly change AC, but may PUSHF/POPF.
+ */
+static const char *uaccess_safe_builtin[] = {
+	/* KASAN */
+	"kasan_report",
+	"kasan_check_range",
+	/* KASAN out-of-line */
+	"__asan_loadN_noabort",
+	"__asan_load1_noabort",
+	"__asan_load2_noabort",
+	"__asan_load4_noabort",
+	"__asan_load8_noabort",
+	"__asan_load16_noabort",
+	"__asan_storeN_noabort",
+	"__asan_store1_noabort",
+	"__asan_store2_noabort",
+	"__asan_store4_noabort",
+	"__asan_store8_noabort",
+	"__asan_store16_noabort",
+	"__kasan_check_read",
+	"__kasan_check_write",
+	/* KASAN in-line */
+	"__asan_report_load_n_noabort",
+	"__asan_report_load1_noabort",
+	"__asan_report_load2_noabort",
+	"__asan_report_load4_noabort",
+	"__asan_report_load8_noabort",
+	"__asan_report_load16_noabort",
+	"__asan_report_store_n_noabort",
+	"__asan_report_store1_noabort",
+	"__asan_report_store2_noabort",
+	"__asan_report_store4_noabort",
+	"__asan_report_store8_noabort",
+	"__asan_report_store16_noabort",
+	/* KCSAN */
+	"__kcsan_check_access",
+	"__kcsan_mb",
+	"__kcsan_wmb",
+	"__kcsan_rmb",
+	"__kcsan_release",
+	"kcsan_found_watchpoint",
+	"kcsan_setup_watchpoint",
+	"kcsan_check_scoped_accesses",
+	"kcsan_disable_current",
+	"kcsan_enable_current_nowarn",
+	/* KCSAN/TSAN */
+	"__tsan_func_entry",
+	"__tsan_func_exit",
+	"__tsan_read_range",
+	"__tsan_write_range",
+	"__tsan_read1",
+	"__tsan_read2",
+	"__tsan_read4",
+	"__tsan_read8",
+	"__tsan_read16",
+	"__tsan_write1",
+	"__tsan_write2",
+	"__tsan_write4",
+	"__tsan_write8",
+	"__tsan_write16",
+	"__tsan_read_write1",
+	"__tsan_read_write2",
+	"__tsan_read_write4",
+	"__tsan_read_write8",
+	"__tsan_read_write16",
+	"__tsan_volatile_read1",
+	"__tsan_volatile_read2",
+	"__tsan_volatile_read4",
+	"__tsan_volatile_read8",
+	"__tsan_volatile_read16",
+	"__tsan_volatile_write1",
+	"__tsan_volatile_write2",
+	"__tsan_volatile_write4",
+	"__tsan_volatile_write8",
+	"__tsan_volatile_write16",
+	"__tsan_atomic8_load",
+	"__tsan_atomic16_load",
+	"__tsan_atomic32_load",
+	"__tsan_atomic64_load",
+	"__tsan_atomic8_store",
+	"__tsan_atomic16_store",
+	"__tsan_atomic32_store",
+	"__tsan_atomic64_store",
+	"__tsan_atomic8_exchange",
+	"__tsan_atomic16_exchange",
+	"__tsan_atomic32_exchange",
+	"__tsan_atomic64_exchange",
+	"__tsan_atomic8_fetch_add",
+	"__tsan_atomic16_fetch_add",
+	"__tsan_atomic32_fetch_add",
+	"__tsan_atomic64_fetch_add",
+	"__tsan_atomic8_fetch_sub",
+	"__tsan_atomic16_fetch_sub",
+	"__tsan_atomic32_fetch_sub",
+	"__tsan_atomic64_fetch_sub",
+	"__tsan_atomic8_fetch_and",
+	"__tsan_atomic16_fetch_and",
+	"__tsan_atomic32_fetch_and",
+	"__tsan_atomic64_fetch_and",
+	"__tsan_atomic8_fetch_or",
+	"__tsan_atomic16_fetch_or",
+	"__tsan_atomic32_fetch_or",
+	"__tsan_atomic64_fetch_or",
+	"__tsan_atomic8_fetch_xor",
+	"__tsan_atomic16_fetch_xor",
+	"__tsan_atomic32_fetch_xor",
+	"__tsan_atomic64_fetch_xor",
+	"__tsan_atomic8_fetch_nand",
+	"__tsan_atomic16_fetch_nand",
+	"__tsan_atomic32_fetch_nand",
+	"__tsan_atomic64_fetch_nand",
+	"__tsan_atomic8_compare_exchange_strong",
+	"__tsan_atomic16_compare_exchange_strong",
+	"__tsan_atomic32_compare_exchange_strong",
+	"__tsan_atomic64_compare_exchange_strong",
+	"__tsan_atomic8_compare_exchange_weak",
+	"__tsan_atomic16_compare_exchange_weak",
+	"__tsan_atomic32_compare_exchange_weak",
+	"__tsan_atomic64_compare_exchange_weak",
+	"__tsan_atomic8_compare_exchange_val",
+	"__tsan_atomic16_compare_exchange_val",
+	"__tsan_atomic32_compare_exchange_val",
+	"__tsan_atomic64_compare_exchange_val",
+	"__tsan_atomic_thread_fence",
+	"__tsan_atomic_signal_fence",
+	"__tsan_unaligned_read16",
+	"__tsan_unaligned_write16",
+	/* KCOV */
+	"write_comp_data",
+	"check_kcov_mode",
+	"__sanitizer_cov_trace_pc",
+	"__sanitizer_cov_trace_const_cmp1",
+	"__sanitizer_cov_trace_const_cmp2",
+	"__sanitizer_cov_trace_const_cmp4",
+	"__sanitizer_cov_trace_const_cmp8",
+	"__sanitizer_cov_trace_cmp1",
+	"__sanitizer_cov_trace_cmp2",
+	"__sanitizer_cov_trace_cmp4",
+	"__sanitizer_cov_trace_cmp8",
+	"__sanitizer_cov_trace_switch",
+	/* KMSAN */
+	"kmsan_copy_to_user",
+	"kmsan_report",
+	"kmsan_unpoison_entry_regs",
+	"kmsan_unpoison_memory",
+	"__msan_chain_origin",
+	"__msan_get_context_state",
+	"__msan_instrument_asm_store",
+	"__msan_metadata_ptr_for_load_1",
+	"__msan_metadata_ptr_for_load_2",
+	"__msan_metadata_ptr_for_load_4",
+	"__msan_metadata_ptr_for_load_8",
+	"__msan_metadata_ptr_for_load_n",
+	"__msan_metadata_ptr_for_store_1",
+	"__msan_metadata_ptr_for_store_2",
+	"__msan_metadata_ptr_for_store_4",
+	"__msan_metadata_ptr_for_store_8",
+	"__msan_metadata_ptr_for_store_n",
+	"__msan_poison_alloca",
+	"__msan_warning",
+	/* UBSAN */
+	"ubsan_type_mismatch_common",
+	"__ubsan_handle_type_mismatch",
+	"__ubsan_handle_type_mismatch_v1",
+	"__ubsan_handle_shift_out_of_bounds",
+	"__ubsan_handle_load_invalid_value",
+	/* STACKLEAK */
+	"stackleak_track_stack",
+	/* misc */
+	"csum_partial_copy_generic",
+	"copy_mc_fragile",
+	"copy_mc_fragile_handle_tail",
+	"copy_mc_enhanced_fast_string",
+	"ftrace_likely_update", /* CONFIG_TRACE_BRANCH_PROFILING */
+	"rep_stos_alternative",
+	"rep_movs_alternative",
+	"__copy_user_nocache",
+	NULL
+};
+
+static void add_uaccess_safe(struct objtool_file *file)
+{
+	struct symbol *func;
+	const char **name;
+
+	if (!opts.uaccess)
+		return;
+
+	for (name = uaccess_safe_builtin; *name; name++) {
+		func = find_symbol_by_name(file->elf, *name);
+		if (!func)
+			continue;
+
+		func->uaccess_safe = true;
+	}
+}
+
+/*
+ * FIXME: For now, just ignore any alternatives which add retpolines.  This is
+ * a temporary hack, as it doesn't allow ORC to unwind from inside a retpoline.
+ * But it at least allows objtool to understand the control flow *around* the
+ * retpoline.
+ */
+static int add_ignore_alternatives(struct objtool_file *file)
+{
+	struct section *rsec;
+	struct reloc *reloc;
+	struct instruction *insn;
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.ignore_alts");
+	if (!rsec)
+		return 0;
+
+	for_each_reloc(rsec, reloc) {
+		if (reloc->sym->type != STT_SECTION) {
+			WARN("unexpected relocation symbol type in %s", rsec->name);
+			return -1;
+		}
+
+		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (!insn) {
+			WARN("bad .discard.ignore_alts entry");
+			return -1;
+		}
+
+		insn->ignore_alts = true;
+	}
+
+	return 0;
+}
+
+/*
+ * Symbols that replace INSN_CALL_DYNAMIC, every (tail) call to such a symbol
+ * will be added to the .retpoline_sites section.
+ */
+__weak bool arch_is_retpoline(struct symbol *sym)
+{
+	return false;
+}
+
+/*
+ * Symbols that replace INSN_RETURN, every (tail) call to such a symbol
+ * will be added to the .return_sites section.
+ */
+__weak bool arch_is_rethunk(struct symbol *sym)
+{
+	return false;
+}
+
+/*
+ * Symbols that are embedded inside other instructions, because sometimes crazy
+ * code exists. These are mostly ignored for validation purposes.
+ */
+__weak bool arch_is_embedded_insn(struct symbol *sym)
+{
+	return false;
+}
+
+static struct reloc *insn_reloc(struct objtool_file *file, struct instruction *insn)
+{
+	struct reloc *reloc;
+
+	if (insn->no_reloc)
+		return NULL;
+
+	if (!file)
+		return NULL;
+
+	reloc = find_reloc_by_dest_range(file->elf, insn->sec,
+					 insn->offset, insn->len);
+	if (!reloc) {
+		insn->no_reloc = 1;
+		return NULL;
+	}
+
+	return reloc;
+}
+
+static void remove_insn_ops(struct instruction *insn)
+{
+	struct stack_op *op, *next;
+
+	for (op = insn->stack_ops; op; op = next) {
+		next = op->next;
+		free(op);
+	}
+	insn->stack_ops = NULL;
+}
+
+static void annotate_call_site(struct objtool_file *file,
+			       struct instruction *insn, bool sibling)
+{
+	struct reloc *reloc = insn_reloc(file, insn);
+	struct symbol *sym = insn_call_dest(insn);
+
+	if (!sym)
+		sym = reloc->sym;
+
+	/*
+	 * Alternative replacement code is just template code which is
+	 * sometimes copied to the original instruction. For now, don't
+	 * annotate it. (In the future we might consider annotating the
+	 * original instruction if/when it ever makes sense to do so.)
+	 */
+	if (!strcmp(insn->sec->name, ".altinstr_replacement"))
+		return;
+
+	if (sym->static_call_tramp) {
+		list_add_tail(&insn->call_node, &file->static_call_list);
+		return;
+	}
+
+	if (sym->retpoline_thunk) {
+		list_add_tail(&insn->call_node, &file->retpoline_call_list);
+		return;
+	}
+
+	/*
+	 * Many compilers cannot disable KCOV or sanitizer calls with a function
+	 * attribute so they need a little help, NOP out any such calls from
+	 * noinstr text.
+	 */
+	if (opts.hack_noinstr && insn->sec->noinstr && sym->profiling_func) {
+		if (reloc)
+			set_reloc_type(file->elf, reloc, R_NONE);
+
+		elf_write_insn(file->elf, insn->sec,
+			       insn->offset, insn->len,
+			       sibling ? arch_ret_insn(insn->len)
+			               : arch_nop_insn(insn->len));
+
+		insn->type = sibling ? INSN_RETURN : INSN_NOP;
+
+		if (sibling) {
+			/*
+			 * We've replaced the tail-call JMP insn by two new
+			 * insn: RET; INT3, except we only have a single struct
+			 * insn here. Mark it retpoline_safe to avoid the SLS
+			 * warning, instead of adding another insn.
+			 */
+			insn->retpoline_safe = true;
+		}
+
+		return;
+	}
+
+	if (opts.mcount && sym->fentry) {
+		if (sibling)
+			WARN_INSN(insn, "tail call to __fentry__ !?!?");
+		if (opts.mnop) {
+			if (reloc)
+				set_reloc_type(file->elf, reloc, R_NONE);
+
+			elf_write_insn(file->elf, insn->sec,
+				       insn->offset, insn->len,
+				       arch_nop_insn(insn->len));
+
+			insn->type = INSN_NOP;
+		}
+
+		list_add_tail(&insn->call_node, &file->mcount_loc_list);
+		return;
+	}
+
+	if (insn->type == INSN_CALL && !insn->sec->init)
+		list_add_tail(&insn->call_node, &file->call_list);
+
+	if (!sibling && dead_end_function(file, sym))
+		insn->dead_end = true;
+}
+
+static void add_call_dest(struct objtool_file *file, struct instruction *insn,
+			  struct symbol *dest, bool sibling)
+{
+	insn->_call_dest = dest;
+	if (!dest)
+		return;
+
+	/*
+	 * Whatever stack impact regular CALLs have, should be undone
+	 * by the RETURN of the called function.
+	 *
+	 * Annotated intra-function calls retain the stack_ops but
+	 * are converted to JUMP, see read_intra_function_calls().
+	 */
+	remove_insn_ops(insn);
+
+	annotate_call_site(file, insn, sibling);
+}
+
+static void add_retpoline_call(struct objtool_file *file, struct instruction *insn)
+{
+	/*
+	 * Retpoline calls/jumps are really dynamic calls/jumps in disguise,
+	 * so convert them accordingly.
+	 */
+	switch (insn->type) {
+	case INSN_CALL:
+		insn->type = INSN_CALL_DYNAMIC;
+		break;
+	case INSN_JUMP_UNCONDITIONAL:
+		insn->type = INSN_JUMP_DYNAMIC;
+		break;
+	case INSN_JUMP_CONDITIONAL:
+		insn->type = INSN_JUMP_DYNAMIC_CONDITIONAL;
+		break;
+	default:
+		return;
+	}
+
+	insn->retpoline_safe = true;
+
+	/*
+	 * Whatever stack impact regular CALLs have, should be undone
+	 * by the RETURN of the called function.
+	 *
+	 * Annotated intra-function calls retain the stack_ops but
+	 * are converted to JUMP, see read_intra_function_calls().
+	 */
+	remove_insn_ops(insn);
+
+	annotate_call_site(file, insn, false);
+}
+
+static void add_return_call(struct objtool_file *file, struct instruction *insn, bool add)
+{
+	/*
+	 * Return thunk tail calls are really just returns in disguise,
+	 * so convert them accordingly.
+	 */
+	insn->type = INSN_RETURN;
+	insn->retpoline_safe = true;
+
+	if (add)
+		list_add_tail(&insn->call_node, &file->return_thunk_list);
+}
+
+static bool is_first_func_insn(struct objtool_file *file,
+			       struct instruction *insn, struct symbol *sym)
+{
+	if (insn->offset == sym->offset)
+		return true;
+
+	/* Allow direct CALL/JMP past ENDBR */
+	if (opts.ibt) {
+		struct instruction *prev = prev_insn_same_sym(file, insn);
+
+		if (prev && prev->type == INSN_ENDBR &&
+		    insn->offset == sym->offset + prev->len)
+			return true;
+	}
+
+	return false;
+}
+
+/*
+ * A sibling call is a tail-call to another symbol -- to differentiate from a
+ * recursive tail-call which is to the same symbol.
+ */
+static bool jump_is_sibling_call(struct objtool_file *file,
+				 struct instruction *from, struct instruction *to)
+{
+	struct symbol *fs = from->sym;
+	struct symbol *ts = to->sym;
+
+	/* Not a sibling call if from/to a symbol hole */
+	if (!fs || !ts)
+		return false;
+
+	/* Not a sibling call if not targeting the start of a symbol. */
+	if (!is_first_func_insn(file, to, ts))
+		return false;
+
+	/* Disallow sibling calls into STT_NOTYPE */
+	if (ts->type == STT_NOTYPE)
+		return false;
+
+	/* Must not be self to be a sibling */
+	return fs->pfunc != ts->pfunc;
+}
+
+/*
+ * Find the destination instructions for all jumps.
+ */
+static int add_jump_destinations(struct objtool_file *file)
+{
+	struct instruction *insn, *jump_dest;
+	struct reloc *reloc;
+	struct section *dest_sec;
+	unsigned long dest_off;
+
+	for_each_insn(file, insn) {
+		if (insn->jump_dest) {
+			/*
+			 * handle_group_alt() may have previously set
+			 * 'jump_dest' for some alternatives.
+			 */
+			continue;
+		}
+		if (!is_static_jump(insn))
+			continue;
+
+		reloc = insn_reloc(file, insn);
+		if (!reloc) {
+			dest_sec = insn->sec;
+			dest_off = arch_jump_destination(insn);
+		} else if (reloc->sym->type == STT_SECTION) {
+			dest_sec = reloc->sym->sec;
+			dest_off = arch_dest_reloc_offset(reloc_addend(reloc));
+		} else if (reloc->sym->retpoline_thunk) {
+			add_retpoline_call(file, insn);
+			continue;
+		} else if (reloc->sym->return_thunk) {
+			add_return_call(file, insn, true);
+			continue;
+		} else if (insn_func(insn)) {
+			/*
+			 * External sibling call or internal sibling call with
+			 * STT_FUNC reloc.
+			 */
+			add_call_dest(file, insn, reloc->sym, true);
+			continue;
+		} else if (reloc->sym->sec->idx) {
+			dest_sec = reloc->sym->sec;
+			dest_off = reloc->sym->sym.st_value +
+				   arch_dest_reloc_offset(reloc_addend(reloc));
+		} else {
+			/* non-func asm code jumping to another file */
+			continue;
+		}
+
+		jump_dest = find_insn(file, dest_sec, dest_off);
+		if (!jump_dest) {
+			struct symbol *sym = find_symbol_by_offset(dest_sec, dest_off);
+
+			/*
+			 * This is a special case for retbleed_untrain_ret().
+			 * It jumps to __x86_return_thunk(), but objtool
+			 * can't find the thunk's starting RET
+			 * instruction, because the RET is also in the
+			 * middle of another instruction.  Objtool only
+			 * knows about the outer instruction.
+			 */
+			if (sym && sym->embedded_insn) {
+				add_return_call(file, insn, false);
+				continue;
+			}
+
+			WARN_INSN(insn, "can't find jump dest instruction at %s+0x%lx",
+				  dest_sec->name, dest_off);
+			return -1;
+		}
+
+		/*
+		 * Cross-function jump.
+		 */
+		if (insn_func(insn) && insn_func(jump_dest) &&
+		    insn_func(insn) != insn_func(jump_dest)) {
+
+			/*
+			 * For GCC 8+, create parent/child links for any cold
+			 * subfunctions.  This is _mostly_ redundant with a
+			 * similar initialization in read_symbols().
+			 *
+			 * If a function has aliases, we want the *first* such
+			 * function in the symbol table to be the subfunction's
+			 * parent.  In that case we overwrite the
+			 * initialization done in read_symbols().
+			 *
+			 * However this code can't completely replace the
+			 * read_symbols() code because this doesn't detect the
+			 * case where the parent function's only reference to a
+			 * subfunction is through a jump table.
+			 */
+			if (!strstr(insn_func(insn)->name, ".cold") &&
+			    strstr(insn_func(jump_dest)->name, ".cold")) {
+				insn_func(insn)->cfunc = insn_func(jump_dest);
+				insn_func(jump_dest)->pfunc = insn_func(insn);
+			}
+		}
+
+		if (jump_is_sibling_call(file, insn, jump_dest)) {
+			/*
+			 * Internal sibling call without reloc or with
+			 * STT_SECTION reloc.
+			 */
+			add_call_dest(file, insn, insn_func(jump_dest), true);
+			continue;
+		}
+
+		insn->jump_dest = jump_dest;
+	}
+
+	return 0;
+}
+
+static struct symbol *find_call_destination(struct section *sec, unsigned long offset)
+{
+	struct symbol *call_dest;
+
+	call_dest = find_func_by_offset(sec, offset);
+	if (!call_dest)
+		call_dest = find_symbol_by_offset(sec, offset);
+
+	return call_dest;
+}
+
+/*
+ * Find the destination instructions for all calls.
+ */
+static int add_call_destinations(struct objtool_file *file)
+{
+	struct instruction *insn;
+	unsigned long dest_off;
+	struct symbol *dest;
+	struct reloc *reloc;
+
+	for_each_insn(file, insn) {
+		if (insn->type != INSN_CALL)
+			continue;
+
+		reloc = insn_reloc(file, insn);
+		if (!reloc) {
+			dest_off = arch_jump_destination(insn);
+			dest = find_call_destination(insn->sec, dest_off);
+
+			add_call_dest(file, insn, dest, false);
+
+			if (insn->ignore)
+				continue;
+
+			if (!insn_call_dest(insn)) {
+				WARN_INSN(insn, "unannotated intra-function call");
+				return -1;
+			}
+
+			if (insn_func(insn) && insn_call_dest(insn)->type != STT_FUNC) {
+				WARN_INSN(insn, "unsupported call to non-function");
+				return -1;
+			}
+
+		} else if (reloc->sym->type == STT_SECTION) {
+			dest_off = arch_dest_reloc_offset(reloc_addend(reloc));
+			dest = find_call_destination(reloc->sym->sec, dest_off);
+			if (!dest) {
+				WARN_INSN(insn, "can't find call dest symbol at %s+0x%lx",
+					  reloc->sym->sec->name, dest_off);
+				return -1;
+			}
+
+			add_call_dest(file, insn, dest, false);
+
+		} else if (reloc->sym->retpoline_thunk) {
+			add_retpoline_call(file, insn);
+
+		} else
+			add_call_dest(file, insn, reloc->sym, false);
+	}
+
+	return 0;
+}
+
+/*
+ * The .alternatives section requires some extra special care over and above
+ * other special sections because alternatives are patched in place.
+ */
+static int handle_group_alt(struct objtool_file *file,
+			    struct special_alt *special_alt,
+			    struct instruction *orig_insn,
+			    struct instruction **new_insn)
+{
+	struct instruction *last_new_insn = NULL, *insn, *nop = NULL;
+	struct alt_group *orig_alt_group, *new_alt_group;
+	unsigned long dest_off;
+
+	orig_alt_group = orig_insn->alt_group;
+	if (!orig_alt_group) {
+		struct instruction *last_orig_insn = NULL;
+
+		orig_alt_group = malloc(sizeof(*orig_alt_group));
+		if (!orig_alt_group) {
+			WARN("malloc failed");
+			return -1;
+		}
+		orig_alt_group->cfi = calloc(special_alt->orig_len,
+					     sizeof(struct cfi_state *));
+		if (!orig_alt_group->cfi) {
+			WARN("calloc failed");
+			return -1;
+		}
+
+		insn = orig_insn;
+		sec_for_each_insn_from(file, insn) {
+			if (insn->offset >= special_alt->orig_off + special_alt->orig_len)
+				break;
+
+			insn->alt_group = orig_alt_group;
+			last_orig_insn = insn;
+		}
+		orig_alt_group->orig_group = NULL;
+		orig_alt_group->first_insn = orig_insn;
+		orig_alt_group->last_insn = last_orig_insn;
+		orig_alt_group->nop = NULL;
+	} else {
+		if (orig_alt_group->last_insn->offset + orig_alt_group->last_insn->len -
+		    orig_alt_group->first_insn->offset != special_alt->orig_len) {
+			WARN_INSN(orig_insn, "weirdly overlapping alternative! %ld != %d",
+				  orig_alt_group->last_insn->offset +
+				  orig_alt_group->last_insn->len -
+				  orig_alt_group->first_insn->offset,
+				  special_alt->orig_len);
+			return -1;
+		}
+	}
+
+	new_alt_group = malloc(sizeof(*new_alt_group));
+	if (!new_alt_group) {
+		WARN("malloc failed");
+		return -1;
+	}
+
+	if (special_alt->new_len < special_alt->orig_len) {
+		/*
+		 * Insert a fake nop at the end to make the replacement
+		 * alt_group the same size as the original.  This is needed to
+		 * allow propagate_alt_cfi() to do its magic.  When the last
+		 * instruction affects the stack, the instruction after it (the
+		 * nop) will propagate the new state to the shared CFI array.
+		 */
+		nop = malloc(sizeof(*nop));
+		if (!nop) {
+			WARN("malloc failed");
+			return -1;
+		}
+		memset(nop, 0, sizeof(*nop));
+
+		nop->sec = special_alt->new_sec;
+		nop->offset = special_alt->new_off + special_alt->new_len;
+		nop->len = special_alt->orig_len - special_alt->new_len;
+		nop->type = INSN_NOP;
+		nop->sym = orig_insn->sym;
+		nop->alt_group = new_alt_group;
+		nop->ignore = orig_insn->ignore_alts;
+	}
+
+	if (!special_alt->new_len) {
+		*new_insn = nop;
+		goto end;
+	}
+
+	insn = *new_insn;
+	sec_for_each_insn_from(file, insn) {
+		struct reloc *alt_reloc;
+
+		if (insn->offset >= special_alt->new_off + special_alt->new_len)
+			break;
+
+		last_new_insn = insn;
+
+		insn->ignore = orig_insn->ignore_alts;
+		insn->sym = orig_insn->sym;
+		insn->alt_group = new_alt_group;
+
+		/*
+		 * Since alternative replacement code is copy/pasted by the
+		 * kernel after applying relocations, generally such code can't
+		 * have relative-address relocation references to outside the
+		 * .altinstr_replacement section, unless the arch's
+		 * alternatives code can adjust the relative offsets
+		 * accordingly.
+		 */
+		alt_reloc = insn_reloc(file, insn);
+		if (alt_reloc && arch_pc_relative_reloc(alt_reloc) &&
+		    !arch_support_alt_relocation(special_alt, insn, alt_reloc)) {
+
+			WARN_INSN(insn, "unsupported relocation in alternatives section");
+			return -1;
+		}
+
+		if (!is_static_jump(insn))
+			continue;
+
+		if (!insn->immediate)
+			continue;
+
+		dest_off = arch_jump_destination(insn);
+		if (dest_off == special_alt->new_off + special_alt->new_len) {
+			insn->jump_dest = next_insn_same_sec(file, orig_alt_group->last_insn);
+			if (!insn->jump_dest) {
+				WARN_INSN(insn, "can't find alternative jump destination");
+				return -1;
+			}
+		}
+	}
+
+	if (!last_new_insn) {
+		WARN_FUNC("can't find last new alternative instruction",
+			  special_alt->new_sec, special_alt->new_off);
+		return -1;
+	}
+
+end:
+	new_alt_group->orig_group = orig_alt_group;
+	new_alt_group->first_insn = *new_insn;
+	new_alt_group->last_insn = last_new_insn;
+	new_alt_group->nop = nop;
+	new_alt_group->cfi = orig_alt_group->cfi;
+	return 0;
+}
+
+/*
+ * A jump table entry can either convert a nop to a jump or a jump to a nop.
+ * If the original instruction is a jump, make the alt entry an effective nop
+ * by just skipping the original instruction.
+ */
+static int handle_jump_alt(struct objtool_file *file,
+			   struct special_alt *special_alt,
+			   struct instruction *orig_insn,
+			   struct instruction **new_insn)
+{
+	if (orig_insn->type != INSN_JUMP_UNCONDITIONAL &&
+	    orig_insn->type != INSN_NOP) {
+
+		WARN_INSN(orig_insn, "unsupported instruction at jump label");
+		return -1;
+	}
+
+	if (opts.hack_jump_label && special_alt->key_addend & 2) {
+		struct reloc *reloc = insn_reloc(file, orig_insn);
+
+		if (reloc)
+			set_reloc_type(file->elf, reloc, R_NONE);
+		elf_write_insn(file->elf, orig_insn->sec,
+			       orig_insn->offset, orig_insn->len,
+			       arch_nop_insn(orig_insn->len));
+		orig_insn->type = INSN_NOP;
+	}
+
+	if (orig_insn->type == INSN_NOP) {
+		if (orig_insn->len == 2)
+			file->jl_nop_short++;
+		else
+			file->jl_nop_long++;
+
+		return 0;
+	}
+
+	if (orig_insn->len == 2)
+		file->jl_short++;
+	else
+		file->jl_long++;
+
+	*new_insn = next_insn_same_sec(file, orig_insn);
+	return 0;
+}
+
+/*
+ * Read all the special sections which have alternate instructions which can be
+ * patched in or redirected to at runtime.  Each instruction having alternate
+ * instruction(s) has them added to its insn->alts list, which will be
+ * traversed in validate_branch().
+ */
+static int add_special_section_alts(struct objtool_file *file)
+{
+	struct list_head special_alts;
+	struct instruction *orig_insn, *new_insn;
+	struct special_alt *special_alt, *tmp;
+	struct alternative *alt;
+	int ret;
+
+	ret = special_get_alts(file->elf, &special_alts);
+	if (ret)
+		return ret;
+
+	list_for_each_entry_safe(special_alt, tmp, &special_alts, list) {
+
+		orig_insn = find_insn(file, special_alt->orig_sec,
+				      special_alt->orig_off);
+		if (!orig_insn) {
+			WARN_FUNC("special: can't find orig instruction",
+				  special_alt->orig_sec, special_alt->orig_off);
+			ret = -1;
+			goto out;
+		}
+
+		new_insn = NULL;
+		if (!special_alt->group || special_alt->new_len) {
+			new_insn = find_insn(file, special_alt->new_sec,
+					     special_alt->new_off);
+			if (!new_insn) {
+				WARN_FUNC("special: can't find new instruction",
+					  special_alt->new_sec,
+					  special_alt->new_off);
+				ret = -1;
+				goto out;
+			}
+		}
+
+		if (special_alt->group) {
+			if (!special_alt->orig_len) {
+				WARN_INSN(orig_insn, "empty alternative entry");
+				continue;
+			}
+
+			ret = handle_group_alt(file, special_alt, orig_insn,
+					       &new_insn);
+			if (ret)
+				goto out;
+		} else if (special_alt->jump_or_nop) {
+			ret = handle_jump_alt(file, special_alt, orig_insn,
+					      &new_insn);
+			if (ret)
+				goto out;
+		}
+
+		alt = malloc(sizeof(*alt));
+		if (!alt) {
+			WARN("malloc failed");
+			ret = -1;
+			goto out;
+		}
+
+		alt->insn = new_insn;
+		alt->skip_orig = special_alt->skip_orig;
+		orig_insn->ignore_alts |= special_alt->skip_alt;
+		alt->next = orig_insn->alts;
+		orig_insn->alts = alt;
+
+		list_del(&special_alt->list);
+		free(special_alt);
+	}
+
+	if (opts.stats) {
+		printf("jl\\\tNOP\tJMP\n");
+		printf("short:\t%ld\t%ld\n", file->jl_nop_short, file->jl_short);
+		printf("long:\t%ld\t%ld\n", file->jl_nop_long, file->jl_long);
+	}
+
+out:
+	return ret;
+}
+
+static int add_jump_table(struct objtool_file *file, struct instruction *insn,
+			  struct reloc *next_table)
+{
+	struct symbol *pfunc = insn_func(insn)->pfunc;
+	struct reloc *table = insn_jump_table(insn);
+	struct instruction *dest_insn;
+	unsigned int prev_offset = 0;
+	struct reloc *reloc = table;
+	struct alternative *alt;
+
+	/*
+	 * Each @reloc is a switch table relocation which points to the target
+	 * instruction.
+	 */
+	for_each_reloc_from(table->sec, reloc) {
+
+		/* Check for the end of the table: */
+		if (reloc != table && reloc == next_table)
+			break;
+
+		/* Make sure the table entries are consecutive: */
+		if (prev_offset && reloc_offset(reloc) != prev_offset + 8)
+			break;
+
+		/* Detect function pointers from contiguous objects: */
+		if (reloc->sym->sec == pfunc->sec &&
+		    reloc_addend(reloc) == pfunc->offset)
+			break;
+
+		dest_insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (!dest_insn)
+			break;
+
+		/* Make sure the destination is in the same function: */
+		if (!insn_func(dest_insn) || insn_func(dest_insn)->pfunc != pfunc)
+			break;
+
+		alt = malloc(sizeof(*alt));
+		if (!alt) {
+			WARN("malloc failed");
+			return -1;
+		}
+
+		alt->insn = dest_insn;
+		alt->next = insn->alts;
+		insn->alts = alt;
+		prev_offset = reloc_offset(reloc);
+	}
+
+	if (!prev_offset) {
+		WARN_INSN(insn, "can't find switch jump table");
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * find_jump_table() - Given a dynamic jump, find the switch jump table
+ * associated with it.
+ */
+static struct reloc *find_jump_table(struct objtool_file *file,
+				      struct symbol *func,
+				      struct instruction *insn)
+{
+	struct reloc *table_reloc;
+	struct instruction *dest_insn, *orig_insn = insn;
+
+	/*
+	 * Backward search using the @first_jump_src links, these help avoid
+	 * much of the 'in between' code. Which avoids us getting confused by
+	 * it.
+	 */
+	for (;
+	     insn && insn_func(insn) && insn_func(insn)->pfunc == func;
+	     insn = insn->first_jump_src ?: prev_insn_same_sym(file, insn)) {
+
+		if (insn != orig_insn && insn->type == INSN_JUMP_DYNAMIC)
+			break;
+
+		/* allow small jumps within the range */
+		if (insn->type == INSN_JUMP_UNCONDITIONAL &&
+		    insn->jump_dest &&
+		    (insn->jump_dest->offset <= insn->offset ||
+		     insn->jump_dest->offset > orig_insn->offset))
+		    break;
+
+		table_reloc = arch_find_switch_table(file, insn);
+		if (!table_reloc)
+			continue;
+		dest_insn = find_insn(file, table_reloc->sym->sec, reloc_addend(table_reloc));
+		if (!dest_insn || !insn_func(dest_insn) || insn_func(dest_insn)->pfunc != func)
+			continue;
+
+		return table_reloc;
+	}
+
+	return NULL;
+}
+
+/*
+ * First pass: Mark the head of each jump table so that in the next pass,
+ * we know when a given jump table ends and the next one starts.
+ */
+static void mark_func_jump_tables(struct objtool_file *file,
+				    struct symbol *func)
+{
+	struct instruction *insn, *last = NULL;
+	struct reloc *reloc;
+
+	func_for_each_insn(file, func, insn) {
+		if (!last)
+			last = insn;
+
+		/*
+		 * Store back-pointers for unconditional forward jumps such
+		 * that find_jump_table() can back-track using those and
+		 * avoid some potentially confusing code.
+		 */
+		if (insn->type == INSN_JUMP_UNCONDITIONAL && insn->jump_dest &&
+		    insn->offset > last->offset &&
+		    insn->jump_dest->offset > insn->offset &&
+		    !insn->jump_dest->first_jump_src) {
+
+			insn->jump_dest->first_jump_src = insn;
+			last = insn->jump_dest;
+		}
+
+		if (insn->type != INSN_JUMP_DYNAMIC)
+			continue;
+
+		reloc = find_jump_table(file, func, insn);
+		if (reloc)
+			insn->_jump_table = reloc;
+	}
+}
+
+static int add_func_jump_tables(struct objtool_file *file,
+				  struct symbol *func)
+{
+	struct instruction *insn, *insn_t1 = NULL, *insn_t2;
+	int ret = 0;
+
+	func_for_each_insn(file, func, insn) {
+		if (!insn_jump_table(insn))
+			continue;
+
+		if (!insn_t1) {
+			insn_t1 = insn;
+			continue;
+		}
+
+		insn_t2 = insn;
+
+		ret = add_jump_table(file, insn_t1, insn_jump_table(insn_t2));
+		if (ret)
+			return ret;
+
+		insn_t1 = insn_t2;
+	}
+
+	if (insn_t1)
+		ret = add_jump_table(file, insn_t1, NULL);
+
+	return ret;
+}
+
+/*
+ * For some switch statements, gcc generates a jump table in the .rodata
+ * section which contains a list of addresses within the function to jump to.
+ * This finds these jump tables and adds them to the insn->alts lists.
+ */
+static int add_jump_table_alts(struct objtool_file *file)
+{
+	struct symbol *func;
+	int ret;
+
+	if (!file->rodata)
+		return 0;
+
+	for_each_sym(file, func) {
+		if (func->type != STT_FUNC)
+			continue;
+
+		mark_func_jump_tables(file, func);
+		ret = add_func_jump_tables(file, func);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static void set_func_state(struct cfi_state *state)
+{
+	state->cfa = initial_func_cfi.cfa;
+	memcpy(&state->regs, &initial_func_cfi.regs,
+	       CFI_NUM_REGS * sizeof(struct cfi_reg));
+	state->stack_size = initial_func_cfi.cfa.offset;
+	state->type = UNWIND_HINT_TYPE_CALL;
+}
+
+static int read_unwind_hints(struct objtool_file *file)
+{
+	struct cfi_state cfi = init_cfi;
+	struct section *sec;
+	struct unwind_hint *hint;
+	struct instruction *insn;
+	struct reloc *reloc;
+	int i;
+
+	sec = find_section_by_name(file->elf, ".discard.unwind_hints");
+	if (!sec)
+		return 0;
+
+	if (!sec->rsec) {
+		WARN("missing .rela.discard.unwind_hints section");
+		return -1;
+	}
+
+	if (sec->sh.sh_size % sizeof(struct unwind_hint)) {
+		WARN("struct unwind_hint size mismatch");
+		return -1;
+	}
+
+	file->hints = true;
+
+	for (i = 0; i < sec->sh.sh_size / sizeof(struct unwind_hint); i++) {
+		hint = (struct unwind_hint *)sec->data->d_buf + i;
+
+		reloc = find_reloc_by_dest(file->elf, sec, i * sizeof(*hint));
+		if (!reloc) {
+			WARN("can't find reloc for unwind_hints[%d]", i);
+			return -1;
+		}
+
+		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (!insn) {
+			WARN("can't find insn for unwind_hints[%d]", i);
+			return -1;
+		}
+
+		insn->hint = true;
+
+		if (hint->type == UNWIND_HINT_TYPE_UNDEFINED) {
+			insn->cfi = &force_undefined_cfi;
+			continue;
+		}
+
+		if (hint->type == UNWIND_HINT_TYPE_SAVE) {
+			insn->hint = false;
+			insn->save = true;
+			continue;
+		}
+
+		if (hint->type == UNWIND_HINT_TYPE_RESTORE) {
+			insn->restore = true;
+			continue;
+		}
+
+		if (hint->type == UNWIND_HINT_TYPE_REGS_PARTIAL) {
+			struct symbol *sym = find_symbol_by_offset(insn->sec, insn->offset);
+
+			if (sym && sym->bind == STB_GLOBAL) {
+				if (opts.ibt && insn->type != INSN_ENDBR && !insn->noendbr) {
+					WARN_INSN(insn, "UNWIND_HINT_IRET_REGS without ENDBR");
+				}
+			}
+		}
+
+		if (hint->type == UNWIND_HINT_TYPE_FUNC) {
+			insn->cfi = &func_cfi;
+			continue;
+		}
+
+		if (insn->cfi)
+			cfi = *(insn->cfi);
+
+		if (arch_decode_hint_reg(hint->sp_reg, &cfi.cfa.base)) {
+			WARN_INSN(insn, "unsupported unwind_hint sp base reg %d", hint->sp_reg);
+			return -1;
+		}
+
+		cfi.cfa.offset = bswap_if_needed(file->elf, hint->sp_offset);
+		cfi.type = hint->type;
+		cfi.signal = hint->signal;
+
+		insn->cfi = cfi_hash_find_or_add(&cfi);
+	}
+
+	return 0;
+}
+
+static int read_noendbr_hints(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct section *rsec;
+	struct reloc *reloc;
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.noendbr");
+	if (!rsec)
+		return 0;
+
+	for_each_reloc(rsec, reloc) {
+		insn = find_insn(file, reloc->sym->sec,
+				 reloc->sym->offset + reloc_addend(reloc));
+		if (!insn) {
+			WARN("bad .discard.noendbr entry");
+			return -1;
+		}
+
+		insn->noendbr = 1;
+	}
+
+	return 0;
+}
+
+static int read_retpoline_hints(struct objtool_file *file)
+{
+	struct section *rsec;
+	struct instruction *insn;
+	struct reloc *reloc;
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.retpoline_safe");
+	if (!rsec)
+		return 0;
+
+	for_each_reloc(rsec, reloc) {
+		if (reloc->sym->type != STT_SECTION) {
+			WARN("unexpected relocation symbol type in %s", rsec->name);
+			return -1;
+		}
+
+		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (!insn) {
+			WARN("bad .discard.retpoline_safe entry");
+			return -1;
+		}
+
+		if (insn->type != INSN_JUMP_DYNAMIC &&
+		    insn->type != INSN_CALL_DYNAMIC &&
+		    insn->type != INSN_RETURN &&
+		    insn->type != INSN_NOP) {
+			WARN_INSN(insn, "retpoline_safe hint not an indirect jump/call/ret/nop");
+			return -1;
+		}
+
+		insn->retpoline_safe = true;
+	}
+
+	return 0;
+}
+
+static int read_instr_hints(struct objtool_file *file)
+{
+	struct section *rsec;
+	struct instruction *insn;
+	struct reloc *reloc;
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.instr_end");
+	if (!rsec)
+		return 0;
+
+	for_each_reloc(rsec, reloc) {
+		if (reloc->sym->type != STT_SECTION) {
+			WARN("unexpected relocation symbol type in %s", rsec->name);
+			return -1;
+		}
+
+		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (!insn) {
+			WARN("bad .discard.instr_end entry");
+			return -1;
+		}
+
+		insn->instr--;
+	}
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.instr_begin");
+	if (!rsec)
+		return 0;
+
+	for_each_reloc(rsec, reloc) {
+		if (reloc->sym->type != STT_SECTION) {
+			WARN("unexpected relocation symbol type in %s", rsec->name);
+			return -1;
+		}
+
+		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (!insn) {
+			WARN("bad .discard.instr_begin entry");
+			return -1;
+		}
+
+		insn->instr++;
+	}
+
+	return 0;
+}
+
+static int read_validate_unret_hints(struct objtool_file *file)
+{
+	struct section *rsec;
+	struct instruction *insn;
+	struct reloc *reloc;
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.validate_unret");
+	if (!rsec)
+		return 0;
+
+	for_each_reloc(rsec, reloc) {
+		if (reloc->sym->type != STT_SECTION) {
+			WARN("unexpected relocation symbol type in %s", rsec->name);
+			return -1;
+		}
+
+		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (!insn) {
+			WARN("bad .discard.instr_end entry");
+			return -1;
+		}
+		insn->unret = 1;
+	}
+
+	return 0;
+}
+
+
+static int read_intra_function_calls(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct section *rsec;
+	struct reloc *reloc;
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.intra_function_calls");
+	if (!rsec)
+		return 0;
+
+	for_each_reloc(rsec, reloc) {
+		unsigned long dest_off;
+
+		if (reloc->sym->type != STT_SECTION) {
+			WARN("unexpected relocation symbol type in %s",
+			     rsec->name);
+			return -1;
+		}
+
+		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (!insn) {
+			WARN("bad .discard.intra_function_call entry");
+			return -1;
+		}
+
+		if (insn->type != INSN_CALL) {
+			WARN_INSN(insn, "intra_function_call not a direct call");
+			return -1;
+		}
+
+		/*
+		 * Treat intra-function CALLs as JMPs, but with a stack_op.
+		 * See add_call_destinations(), which strips stack_ops from
+		 * normal CALLs.
+		 */
+		insn->type = INSN_JUMP_UNCONDITIONAL;
+
+		dest_off = arch_jump_destination(insn);
+		insn->jump_dest = find_insn(file, insn->sec, dest_off);
+		if (!insn->jump_dest) {
+			WARN_INSN(insn, "can't find call dest at %s+0x%lx",
+				  insn->sec->name, dest_off);
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Return true if name matches an instrumentation function, where calls to that
+ * function from noinstr code can safely be removed, but compilers won't do so.
+ */
+static bool is_profiling_func(const char *name)
+{
+	/*
+	 * Many compilers cannot disable KCOV with a function attribute.
+	 */
+	if (!strncmp(name, "__sanitizer_cov_", 16))
+		return true;
+
+	/*
+	 * Some compilers currently do not remove __tsan_func_entry/exit nor
+	 * __tsan_atomic_signal_fence (used for barrier instrumentation) with
+	 * the __no_sanitize_thread attribute, remove them. Once the kernel's
+	 * minimum Clang version is 14.0, this can be removed.
+	 */
+	if (!strncmp(name, "__tsan_func_", 12) ||
+	    !strcmp(name, "__tsan_atomic_signal_fence"))
+		return true;
+
+	return false;
+}
+
+static int classify_symbols(struct objtool_file *file)
+{
+	struct symbol *func;
+
+	for_each_sym(file, func) {
+		if (func->bind != STB_GLOBAL)
+			continue;
+
+		if (!strncmp(func->name, STATIC_CALL_TRAMP_PREFIX_STR,
+			     strlen(STATIC_CALL_TRAMP_PREFIX_STR)))
+			func->static_call_tramp = true;
+
+		if (arch_is_retpoline(func))
+			func->retpoline_thunk = true;
+
+		if (arch_is_rethunk(func))
+			func->return_thunk = true;
+
+		if (arch_is_embedded_insn(func))
+			func->embedded_insn = true;
+
+		if (arch_ftrace_match(func->name))
+			func->fentry = true;
+
+		if (is_profiling_func(func->name))
+			func->profiling_func = true;
+	}
+
+	return 0;
+}
+
+static void mark_rodata(struct objtool_file *file)
+{
+	struct section *sec;
+	bool found = false;
+
+	/*
+	 * Search for the following rodata sections, each of which can
+	 * potentially contain jump tables:
+	 *
+	 * - .rodata: can contain GCC switch tables
+	 * - .rodata.<func>: same, if -fdata-sections is being used
+	 * - .rodata..c_jump_table: contains C annotated jump tables
+	 *
+	 * .rodata.str1.* sections are ignored; they don't contain jump tables.
+	 */
+	for_each_sec(file, sec) {
+		if (!strncmp(sec->name, ".rodata", 7) &&
+		    !strstr(sec->name, ".str1.")) {
+			sec->rodata = true;
+			found = true;
+		}
+	}
+
+	file->rodata = found;
+}
+
+static int decode_sections(struct objtool_file *file)
+{
+	int ret;
+
+	mark_rodata(file);
+
+	ret = init_pv_ops(file);
+	if (ret)
+		return ret;
+
+	/*
+	 * Must be before add_{jump_call}_destination.
+	 */
+	ret = classify_symbols(file);
+	if (ret)
+		return ret;
+
+	ret = decode_instructions(file);
+	if (ret)
+		return ret;
+
+	add_ignores(file);
+	add_uaccess_safe(file);
+
+	ret = add_ignore_alternatives(file);
+	if (ret)
+		return ret;
+
+	/*
+	 * Must be before read_unwind_hints() since that needs insn->noendbr.
+	 */
+	ret = read_noendbr_hints(file);
+	if (ret)
+		return ret;
+
+	/*
+	 * Must be before add_jump_destinations(), which depends on 'func'
+	 * being set for alternatives, to enable proper sibling call detection.
+	 */
+	if (opts.stackval || opts.orc || opts.uaccess || opts.noinstr) {
+		ret = add_special_section_alts(file);
+		if (ret)
+			return ret;
+	}
+
+	ret = add_jump_destinations(file);
+	if (ret)
+		return ret;
+
+	/*
+	 * Must be before add_call_destination(); it changes INSN_CALL to
+	 * INSN_JUMP.
+	 */
+	ret = read_intra_function_calls(file);
+	if (ret)
+		return ret;
+
+	ret = add_call_destinations(file);
+	if (ret)
+		return ret;
+
+	/*
+	 * Must be after add_call_destinations() such that it can override
+	 * dead_end_function() marks.
+	 */
+	ret = add_dead_ends(file);
+	if (ret)
+		return ret;
+
+	ret = add_jump_table_alts(file);
+	if (ret)
+		return ret;
+
+	ret = read_unwind_hints(file);
+	if (ret)
+		return ret;
+
+	ret = read_retpoline_hints(file);
+	if (ret)
+		return ret;
+
+	ret = read_instr_hints(file);
+	if (ret)
+		return ret;
+
+	ret = read_validate_unret_hints(file);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static bool is_special_call(struct instruction *insn)
+{
+	if (insn->type == INSN_CALL) {
+		struct symbol *dest = insn_call_dest(insn);
+
+		if (!dest)
+			return false;
+
+		if (dest->fentry || dest->embedded_insn)
+			return true;
+	}
+
+	return false;
+}
+
+static bool has_modified_stack_frame(struct instruction *insn, struct insn_state *state)
+{
+	struct cfi_state *cfi = &state->cfi;
+	int i;
+
+	if (cfi->cfa.base != initial_func_cfi.cfa.base || cfi->drap)
+		return true;
+
+	if (cfi->cfa.offset != initial_func_cfi.cfa.offset)
+		return true;
+
+	if (cfi->stack_size != initial_func_cfi.cfa.offset)
+		return true;
+
+	for (i = 0; i < CFI_NUM_REGS; i++) {
+		if (cfi->regs[i].base != initial_func_cfi.regs[i].base ||
+		    cfi->regs[i].offset != initial_func_cfi.regs[i].offset)
+			return true;
+	}
+
+	return false;
+}
+
+static bool check_reg_frame_pos(const struct cfi_reg *reg,
+				int expected_offset)
+{
+	return reg->base == CFI_CFA &&
+	       reg->offset == expected_offset;
+}
+
+static bool has_valid_stack_frame(struct insn_state *state)
+{
+	struct cfi_state *cfi = &state->cfi;
+
+	if (cfi->cfa.base == CFI_BP &&
+	    check_reg_frame_pos(&cfi->regs[CFI_BP], -cfi->cfa.offset) &&
+	    check_reg_frame_pos(&cfi->regs[CFI_RA], -cfi->cfa.offset + 8))
+		return true;
+
+	if (cfi->drap && cfi->regs[CFI_BP].base == CFI_BP)
+		return true;
+
+	return false;
+}
+
+static int update_cfi_state_regs(struct instruction *insn,
+				  struct cfi_state *cfi,
+				  struct stack_op *op)
+{
+	struct cfi_reg *cfa = &cfi->cfa;
+
+	if (cfa->base != CFI_SP && cfa->base != CFI_SP_INDIRECT)
+		return 0;
+
+	/* push */
+	if (op->dest.type == OP_DEST_PUSH || op->dest.type == OP_DEST_PUSHF)
+		cfa->offset += 8;
+
+	/* pop */
+	if (op->src.type == OP_SRC_POP || op->src.type == OP_SRC_POPF)
+		cfa->offset -= 8;
+
+	/* add immediate to sp */
+	if (op->dest.type == OP_DEST_REG && op->src.type == OP_SRC_ADD &&
+	    op->dest.reg == CFI_SP && op->src.reg == CFI_SP)
+		cfa->offset -= op->src.offset;
+
+	return 0;
+}
+
+static void save_reg(struct cfi_state *cfi, unsigned char reg, int base, int offset)
+{
+	if (arch_callee_saved_reg(reg) &&
+	    cfi->regs[reg].base == CFI_UNDEFINED) {
+		cfi->regs[reg].base = base;
+		cfi->regs[reg].offset = offset;
+	}
+}
+
+static void restore_reg(struct cfi_state *cfi, unsigned char reg)
+{
+	cfi->regs[reg].base = initial_func_cfi.regs[reg].base;
+	cfi->regs[reg].offset = initial_func_cfi.regs[reg].offset;
+}
+
+/*
+ * A note about DRAP stack alignment:
+ *
+ * GCC has the concept of a DRAP register, which is used to help keep track of
+ * the stack pointer when aligning the stack.  r10 or r13 is used as the DRAP
+ * register.  The typical DRAP pattern is:
+ *
+ *   4c 8d 54 24 08		lea    0x8(%rsp),%r10
+ *   48 83 e4 c0		and    $0xffffffffffffffc0,%rsp
+ *   41 ff 72 f8		pushq  -0x8(%r10)
+ *   55				push   %rbp
+ *   48 89 e5			mov    %rsp,%rbp
+ *				(more pushes)
+ *   41 52			push   %r10
+ *				...
+ *   41 5a			pop    %r10
+ *				(more pops)
+ *   5d				pop    %rbp
+ *   49 8d 62 f8		lea    -0x8(%r10),%rsp
+ *   c3				retq
+ *
+ * There are some variations in the epilogues, like:
+ *
+ *   5b				pop    %rbx
+ *   41 5a			pop    %r10
+ *   41 5c			pop    %r12
+ *   41 5d			pop    %r13
+ *   41 5e			pop    %r14
+ *   c9				leaveq
+ *   49 8d 62 f8		lea    -0x8(%r10),%rsp
+ *   c3				retq
+ *
+ * and:
+ *
+ *   4c 8b 55 e8		mov    -0x18(%rbp),%r10
+ *   48 8b 5d e0		mov    -0x20(%rbp),%rbx
+ *   4c 8b 65 f0		mov    -0x10(%rbp),%r12
+ *   4c 8b 6d f8		mov    -0x8(%rbp),%r13
+ *   c9				leaveq
+ *   49 8d 62 f8		lea    -0x8(%r10),%rsp
+ *   c3				retq
+ *
+ * Sometimes r13 is used as the DRAP register, in which case it's saved and
+ * restored beforehand:
+ *
+ *   41 55			push   %r13
+ *   4c 8d 6c 24 10		lea    0x10(%rsp),%r13
+ *   48 83 e4 f0		and    $0xfffffffffffffff0,%rsp
+ *				...
+ *   49 8d 65 f0		lea    -0x10(%r13),%rsp
+ *   41 5d			pop    %r13
+ *   c3				retq
+ */
+static int update_cfi_state(struct instruction *insn,
+			    struct instruction *next_insn,
+			    struct cfi_state *cfi, struct stack_op *op)
+{
+	struct cfi_reg *cfa = &cfi->cfa;
+	struct cfi_reg *regs = cfi->regs;
+
+	/* ignore UNWIND_HINT_UNDEFINED regions */
+	if (cfi->force_undefined)
+		return 0;
+
+	/* stack operations don't make sense with an undefined CFA */
+	if (cfa->base == CFI_UNDEFINED) {
+		if (insn_func(insn)) {
+			WARN_INSN(insn, "undefined stack state");
+			return -1;
+		}
+		return 0;
+	}
+
+	if (cfi->type == UNWIND_HINT_TYPE_REGS ||
+	    cfi->type == UNWIND_HINT_TYPE_REGS_PARTIAL)
+		return update_cfi_state_regs(insn, cfi, op);
+
+	switch (op->dest.type) {
+
+	case OP_DEST_REG:
+		switch (op->src.type) {
+
+		case OP_SRC_REG:
+			if (op->src.reg == CFI_SP && op->dest.reg == CFI_BP &&
+			    cfa->base == CFI_SP &&
+			    check_reg_frame_pos(&regs[CFI_BP], -cfa->offset)) {
+
+				/* mov %rsp, %rbp */
+				cfa->base = op->dest.reg;
+				cfi->bp_scratch = false;
+			}
+
+			else if (op->src.reg == CFI_SP &&
+				 op->dest.reg == CFI_BP && cfi->drap) {
+
+				/* drap: mov %rsp, %rbp */
+				regs[CFI_BP].base = CFI_BP;
+				regs[CFI_BP].offset = -cfi->stack_size;
+				cfi->bp_scratch = false;
+			}
+
+			else if (op->src.reg == CFI_SP && cfa->base == CFI_SP) {
+
+				/*
+				 * mov %rsp, %reg
+				 *
+				 * This is needed for the rare case where GCC
+				 * does:
+				 *
+				 *   mov    %rsp, %rax
+				 *   ...
+				 *   mov    %rax, %rsp
+				 */
+				cfi->vals[op->dest.reg].base = CFI_CFA;
+				cfi->vals[op->dest.reg].offset = -cfi->stack_size;
+			}
+
+			else if (op->src.reg == CFI_BP && op->dest.reg == CFI_SP &&
+				 (cfa->base == CFI_BP || cfa->base == cfi->drap_reg)) {
+
+				/*
+				 * mov %rbp, %rsp
+				 *
+				 * Restore the original stack pointer (Clang).
+				 */
+				cfi->stack_size = -cfi->regs[CFI_BP].offset;
+			}
+
+			else if (op->dest.reg == cfa->base) {
+
+				/* mov %reg, %rsp */
+				if (cfa->base == CFI_SP &&
+				    cfi->vals[op->src.reg].base == CFI_CFA) {
+
+					/*
+					 * This is needed for the rare case
+					 * where GCC does something dumb like:
+					 *
+					 *   lea    0x8(%rsp), %rcx
+					 *   ...
+					 *   mov    %rcx, %rsp
+					 */
+					cfa->offset = -cfi->vals[op->src.reg].offset;
+					cfi->stack_size = cfa->offset;
+
+				} else if (cfa->base == CFI_SP &&
+					   cfi->vals[op->src.reg].base == CFI_SP_INDIRECT &&
+					   cfi->vals[op->src.reg].offset == cfa->offset) {
+
+					/*
+					 * Stack swizzle:
+					 *
+					 * 1: mov %rsp, (%[tos])
+					 * 2: mov %[tos], %rsp
+					 *    ...
+					 * 3: pop %rsp
+					 *
+					 * Where:
+					 *
+					 * 1 - places a pointer to the previous
+					 *     stack at the Top-of-Stack of the
+					 *     new stack.
+					 *
+					 * 2 - switches to the new stack.
+					 *
+					 * 3 - pops the Top-of-Stack to restore
+					 *     the original stack.
+					 *
+					 * Note: we set base to SP_INDIRECT
+					 * here and preserve offset. Therefore
+					 * when the unwinder reaches ToS it
+					 * will dereference SP and then add the
+					 * offset to find the next frame, IOW:
+					 * (%rsp) + offset.
+					 */
+					cfa->base = CFI_SP_INDIRECT;
+
+				} else {
+					cfa->base = CFI_UNDEFINED;
+					cfa->offset = 0;
+				}
+			}
+
+			else if (op->dest.reg == CFI_SP &&
+				 cfi->vals[op->src.reg].base == CFI_SP_INDIRECT &&
+				 cfi->vals[op->src.reg].offset == cfa->offset) {
+
+				/*
+				 * The same stack swizzle case 2) as above. But
+				 * because we can't change cfa->base, case 3)
+				 * will become a regular POP. Pretend we're a
+				 * PUSH so things don't go unbalanced.
+				 */
+				cfi->stack_size += 8;
+			}
+
+
+			break;
+
+		case OP_SRC_ADD:
+			if (op->dest.reg == CFI_SP && op->src.reg == CFI_SP) {
+
+				/* add imm, %rsp */
+				cfi->stack_size -= op->src.offset;
+				if (cfa->base == CFI_SP)
+					cfa->offset -= op->src.offset;
+				break;
+			}
+
+			if (op->dest.reg == CFI_SP && op->src.reg == CFI_BP) {
+
+				/* lea disp(%rbp), %rsp */
+				cfi->stack_size = -(op->src.offset + regs[CFI_BP].offset);
+				break;
+			}
+
+			if (op->src.reg == CFI_SP && cfa->base == CFI_SP) {
+
+				/* drap: lea disp(%rsp), %drap */
+				cfi->drap_reg = op->dest.reg;
+
+				/*
+				 * lea disp(%rsp), %reg
+				 *
+				 * This is needed for the rare case where GCC
+				 * does something dumb like:
+				 *
+				 *   lea    0x8(%rsp), %rcx
+				 *   ...
+				 *   mov    %rcx, %rsp
+				 */
+				cfi->vals[op->dest.reg].base = CFI_CFA;
+				cfi->vals[op->dest.reg].offset = \
+					-cfi->stack_size + op->src.offset;
+
+				break;
+			}
+
+			if (cfi->drap && op->dest.reg == CFI_SP &&
+			    op->src.reg == cfi->drap_reg) {
+
+				 /* drap: lea disp(%drap), %rsp */
+				cfa->base = CFI_SP;
+				cfa->offset = cfi->stack_size = -op->src.offset;
+				cfi->drap_reg = CFI_UNDEFINED;
+				cfi->drap = false;
+				break;
+			}
+
+			if (op->dest.reg == cfi->cfa.base && !(next_insn && next_insn->hint)) {
+				WARN_INSN(insn, "unsupported stack register modification");
+				return -1;
+			}
+
+			break;
+
+		case OP_SRC_AND:
+			if (op->dest.reg != CFI_SP ||
+			    (cfi->drap_reg != CFI_UNDEFINED && cfa->base != CFI_SP) ||
+			    (cfi->drap_reg == CFI_UNDEFINED && cfa->base != CFI_BP)) {
+				WARN_INSN(insn, "unsupported stack pointer realignment");
+				return -1;
+			}
+
+			if (cfi->drap_reg != CFI_UNDEFINED) {
+				/* drap: and imm, %rsp */
+				cfa->base = cfi->drap_reg;
+				cfa->offset = cfi->stack_size = 0;
+				cfi->drap = true;
+			}
+
+			/*
+			 * Older versions of GCC (4.8ish) realign the stack
+			 * without DRAP, with a frame pointer.
+			 */
+
+			break;
+
+		case OP_SRC_POP:
+		case OP_SRC_POPF:
+			if (op->dest.reg == CFI_SP && cfa->base == CFI_SP_INDIRECT) {
+
+				/* pop %rsp; # restore from a stack swizzle */
+				cfa->base = CFI_SP;
+				break;
+			}
+
+			if (!cfi->drap && op->dest.reg == cfa->base) {
+
+				/* pop %rbp */
+				cfa->base = CFI_SP;
+			}
+
+			if (cfi->drap && cfa->base == CFI_BP_INDIRECT &&
+			    op->dest.reg == cfi->drap_reg &&
+			    cfi->drap_offset == -cfi->stack_size) {
+
+				/* drap: pop %drap */
+				cfa->base = cfi->drap_reg;
+				cfa->offset = 0;
+				cfi->drap_offset = -1;
+
+			} else if (cfi->stack_size == -regs[op->dest.reg].offset) {
+
+				/* pop %reg */
+				restore_reg(cfi, op->dest.reg);
+			}
+
+			cfi->stack_size -= 8;
+			if (cfa->base == CFI_SP)
+				cfa->offset -= 8;
+
+			break;
+
+		case OP_SRC_REG_INDIRECT:
+			if (!cfi->drap && op->dest.reg == cfa->base &&
+			    op->dest.reg == CFI_BP) {
+
+				/* mov disp(%rsp), %rbp */
+				cfa->base = CFI_SP;
+				cfa->offset = cfi->stack_size;
+			}
+
+			if (cfi->drap && op->src.reg == CFI_BP &&
+			    op->src.offset == cfi->drap_offset) {
+
+				/* drap: mov disp(%rbp), %drap */
+				cfa->base = cfi->drap_reg;
+				cfa->offset = 0;
+				cfi->drap_offset = -1;
+			}
+
+			if (cfi->drap && op->src.reg == CFI_BP &&
+			    op->src.offset == regs[op->dest.reg].offset) {
+
+				/* drap: mov disp(%rbp), %reg */
+				restore_reg(cfi, op->dest.reg);
+
+			} else if (op->src.reg == cfa->base &&
+			    op->src.offset == regs[op->dest.reg].offset + cfa->offset) {
+
+				/* mov disp(%rbp), %reg */
+				/* mov disp(%rsp), %reg */
+				restore_reg(cfi, op->dest.reg);
+
+			} else if (op->src.reg == CFI_SP &&
+				   op->src.offset == regs[op->dest.reg].offset + cfi->stack_size) {
+
+				/* mov disp(%rsp), %reg */
+				restore_reg(cfi, op->dest.reg);
+			}
+
+			break;
+
+		default:
+			WARN_INSN(insn, "unknown stack-related instruction");
+			return -1;
+		}
+
+		break;
+
+	case OP_DEST_PUSH:
+	case OP_DEST_PUSHF:
+		cfi->stack_size += 8;
+		if (cfa->base == CFI_SP)
+			cfa->offset += 8;
+
+		if (op->src.type != OP_SRC_REG)
+			break;
+
+		if (cfi->drap) {
+			if (op->src.reg == cfa->base && op->src.reg == cfi->drap_reg) {
+
+				/* drap: push %drap */
+				cfa->base = CFI_BP_INDIRECT;
+				cfa->offset = -cfi->stack_size;
+
+				/* save drap so we know when to restore it */
+				cfi->drap_offset = -cfi->stack_size;
+
+			} else if (op->src.reg == CFI_BP && cfa->base == cfi->drap_reg) {
+
+				/* drap: push %rbp */
+				cfi->stack_size = 0;
+
+			} else {
+
+				/* drap: push %reg */
+				save_reg(cfi, op->src.reg, CFI_BP, -cfi->stack_size);
+			}
+
+		} else {
+
+			/* push %reg */
+			save_reg(cfi, op->src.reg, CFI_CFA, -cfi->stack_size);
+		}
+
+		/* detect when asm code uses rbp as a scratch register */
+		if (opts.stackval && insn_func(insn) && op->src.reg == CFI_BP &&
+		    cfa->base != CFI_BP)
+			cfi->bp_scratch = true;
+		break;
+
+	case OP_DEST_REG_INDIRECT:
+
+		if (cfi->drap) {
+			if (op->src.reg == cfa->base && op->src.reg == cfi->drap_reg) {
+
+				/* drap: mov %drap, disp(%rbp) */
+				cfa->base = CFI_BP_INDIRECT;
+				cfa->offset = op->dest.offset;
+
+				/* save drap offset so we know when to restore it */
+				cfi->drap_offset = op->dest.offset;
+			} else {
+
+				/* drap: mov reg, disp(%rbp) */
+				save_reg(cfi, op->src.reg, CFI_BP, op->dest.offset);
+			}
+
+		} else if (op->dest.reg == cfa->base) {
+
+			/* mov reg, disp(%rbp) */
+			/* mov reg, disp(%rsp) */
+			save_reg(cfi, op->src.reg, CFI_CFA,
+				 op->dest.offset - cfi->cfa.offset);
+
+		} else if (op->dest.reg == CFI_SP) {
+
+			/* mov reg, disp(%rsp) */
+			save_reg(cfi, op->src.reg, CFI_CFA,
+				 op->dest.offset - cfi->stack_size);
+
+		} else if (op->src.reg == CFI_SP && op->dest.offset == 0) {
+
+			/* mov %rsp, (%reg); # setup a stack swizzle. */
+			cfi->vals[op->dest.reg].base = CFI_SP_INDIRECT;
+			cfi->vals[op->dest.reg].offset = cfa->offset;
+		}
+
+		break;
+
+	case OP_DEST_MEM:
+		if (op->src.type != OP_SRC_POP && op->src.type != OP_SRC_POPF) {
+			WARN_INSN(insn, "unknown stack-related memory operation");
+			return -1;
+		}
+
+		/* pop mem */
+		cfi->stack_size -= 8;
+		if (cfa->base == CFI_SP)
+			cfa->offset -= 8;
+
+		break;
+
+	default:
+		WARN_INSN(insn, "unknown stack-related instruction");
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * The stack layouts of alternatives instructions can sometimes diverge when
+ * they have stack modifications.  That's fine as long as the potential stack
+ * layouts don't conflict at any given potential instruction boundary.
+ *
+ * Flatten the CFIs of the different alternative code streams (both original
+ * and replacement) into a single shared CFI array which can be used to detect
+ * conflicts and nicely feed a linear array of ORC entries to the unwinder.
+ */
+static int propagate_alt_cfi(struct objtool_file *file, struct instruction *insn)
+{
+	struct cfi_state **alt_cfi;
+	int group_off;
+
+	if (!insn->alt_group)
+		return 0;
+
+	if (!insn->cfi) {
+		WARN("CFI missing");
+		return -1;
+	}
+
+	alt_cfi = insn->alt_group->cfi;
+	group_off = insn->offset - insn->alt_group->first_insn->offset;
+
+	if (!alt_cfi[group_off]) {
+		alt_cfi[group_off] = insn->cfi;
+	} else {
+		if (cficmp(alt_cfi[group_off], insn->cfi)) {
+			struct alt_group *orig_group = insn->alt_group->orig_group ?: insn->alt_group;
+			struct instruction *orig = orig_group->first_insn;
+			char *where = offstr(insn->sec, insn->offset);
+			WARN_INSN(orig, "stack layout conflict in alternatives: %s", where);
+			free(where);
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+static int handle_insn_ops(struct instruction *insn,
+			   struct instruction *next_insn,
+			   struct insn_state *state)
+{
+	struct stack_op *op;
+
+	for (op = insn->stack_ops; op; op = op->next) {
+
+		if (update_cfi_state(insn, next_insn, &state->cfi, op))
+			return 1;
+
+		if (!insn->alt_group)
+			continue;
+
+		if (op->dest.type == OP_DEST_PUSHF) {
+			if (!state->uaccess_stack) {
+				state->uaccess_stack = 1;
+			} else if (state->uaccess_stack >> 31) {
+				WARN_INSN(insn, "PUSHF stack exhausted");
+				return 1;
+			}
+			state->uaccess_stack <<= 1;
+			state->uaccess_stack  |= state->uaccess;
+		}
+
+		if (op->src.type == OP_SRC_POPF) {
+			if (state->uaccess_stack) {
+				state->uaccess = state->uaccess_stack & 1;
+				state->uaccess_stack >>= 1;
+				if (state->uaccess_stack == 1)
+					state->uaccess_stack = 0;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static bool insn_cfi_match(struct instruction *insn, struct cfi_state *cfi2)
+{
+	struct cfi_state *cfi1 = insn->cfi;
+	int i;
+
+	if (!cfi1) {
+		WARN("CFI missing");
+		return false;
+	}
+
+	if (memcmp(&cfi1->cfa, &cfi2->cfa, sizeof(cfi1->cfa))) {
+
+		WARN_INSN(insn, "stack state mismatch: cfa1=%d%+d cfa2=%d%+d",
+			  cfi1->cfa.base, cfi1->cfa.offset,
+			  cfi2->cfa.base, cfi2->cfa.offset);
+
+	} else if (memcmp(&cfi1->regs, &cfi2->regs, sizeof(cfi1->regs))) {
+		for (i = 0; i < CFI_NUM_REGS; i++) {
+			if (!memcmp(&cfi1->regs[i], &cfi2->regs[i],
+				    sizeof(struct cfi_reg)))
+				continue;
+
+			WARN_INSN(insn, "stack state mismatch: reg1[%d]=%d%+d reg2[%d]=%d%+d",
+				  i, cfi1->regs[i].base, cfi1->regs[i].offset,
+				  i, cfi2->regs[i].base, cfi2->regs[i].offset);
+			break;
+		}
+
+	} else if (cfi1->type != cfi2->type) {
+
+		WARN_INSN(insn, "stack state mismatch: type1=%d type2=%d",
+			  cfi1->type, cfi2->type);
+
+	} else if (cfi1->drap != cfi2->drap ||
+		   (cfi1->drap && cfi1->drap_reg != cfi2->drap_reg) ||
+		   (cfi1->drap && cfi1->drap_offset != cfi2->drap_offset)) {
+
+		WARN_INSN(insn, "stack state mismatch: drap1=%d(%d,%d) drap2=%d(%d,%d)",
+			  cfi1->drap, cfi1->drap_reg, cfi1->drap_offset,
+			  cfi2->drap, cfi2->drap_reg, cfi2->drap_offset);
+
+	} else
+		return true;
+
+	return false;
+}
+
+static inline bool func_uaccess_safe(struct symbol *func)
+{
+	if (func)
+		return func->uaccess_safe;
+
+	return false;
+}
+
+static inline const char *call_dest_name(struct instruction *insn)
+{
+	static char pvname[19];
+	struct reloc *reloc;
+	int idx;
+
+	if (insn_call_dest(insn))
+		return insn_call_dest(insn)->name;
+
+	reloc = insn_reloc(NULL, insn);
+	if (reloc && !strcmp(reloc->sym->name, "pv_ops")) {
+		idx = (reloc_addend(reloc) / sizeof(void *));
+		snprintf(pvname, sizeof(pvname), "pv_ops[%d]", idx);
+		return pvname;
+	}
+
+	return "{dynamic}";
+}
+
+static bool pv_call_dest(struct objtool_file *file, struct instruction *insn)
+{
+	struct symbol *target;
+	struct reloc *reloc;
+	int idx;
+
+	reloc = insn_reloc(file, insn);
+	if (!reloc || strcmp(reloc->sym->name, "pv_ops"))
+		return false;
+
+	idx = (arch_dest_reloc_offset(reloc_addend(reloc)) / sizeof(void *));
+
+	if (file->pv_ops[idx].clean)
+		return true;
+
+	file->pv_ops[idx].clean = true;
+
+	list_for_each_entry(target, &file->pv_ops[idx].targets, pv_target) {
+		if (!target->sec->noinstr) {
+			WARN("pv_ops[%d]: %s", idx, target->name);
+			file->pv_ops[idx].clean = false;
+		}
+	}
+
+	return file->pv_ops[idx].clean;
+}
+
+static inline bool noinstr_call_dest(struct objtool_file *file,
+				     struct instruction *insn,
+				     struct symbol *func)
+{
+	/*
+	 * We can't deal with indirect function calls at present;
+	 * assume they're instrumented.
+	 */
+	if (!func) {
+		if (file->pv_ops)
+			return pv_call_dest(file, insn);
+
+		return false;
+	}
+
+	/*
+	 * If the symbol is from a noinstr section; we good.
+	 */
+	if (func->sec->noinstr)
+		return true;
+
+	/*
+	 * If the symbol is a static_call trampoline, we can't tell.
+	 */
+	if (func->static_call_tramp)
+		return true;
+
+	/*
+	 * The __ubsan_handle_*() calls are like WARN(), they only happen when
+	 * something 'BAD' happened. At the risk of taking the machine down,
+	 * let them proceed to get the message out.
+	 */
+	if (!strncmp(func->name, "__ubsan_handle_", 15))
+		return true;
+
+	return false;
+}
+
+static int validate_call(struct objtool_file *file,
+			 struct instruction *insn,
+			 struct insn_state *state)
+{
+	if (state->noinstr && state->instr <= 0 &&
+	    !noinstr_call_dest(file, insn, insn_call_dest(insn))) {
+		WARN_INSN(insn, "call to %s() leaves .noinstr.text section", call_dest_name(insn));
+		return 1;
+	}
+
+	if (state->uaccess && !func_uaccess_safe(insn_call_dest(insn))) {
+		WARN_INSN(insn, "call to %s() with UACCESS enabled", call_dest_name(insn));
+		return 1;
+	}
+
+	if (state->df) {
+		WARN_INSN(insn, "call to %s() with DF set", call_dest_name(insn));
+		return 1;
+	}
+
+	return 0;
+}
+
+static int validate_sibling_call(struct objtool_file *file,
+				 struct instruction *insn,
+				 struct insn_state *state)
+{
+	if (insn_func(insn) && has_modified_stack_frame(insn, state)) {
+		WARN_INSN(insn, "sibling call from callable instruction with modified stack frame");
+		return 1;
+	}
+
+	return validate_call(file, insn, state);
+}
+
+static int validate_return(struct symbol *func, struct instruction *insn, struct insn_state *state)
+{
+	if (state->noinstr && state->instr > 0) {
+		WARN_INSN(insn, "return with instrumentation enabled");
+		return 1;
+	}
+
+	if (state->uaccess && !func_uaccess_safe(func)) {
+		WARN_INSN(insn, "return with UACCESS enabled");
+		return 1;
+	}
+
+	if (!state->uaccess && func_uaccess_safe(func)) {
+		WARN_INSN(insn, "return with UACCESS disabled from a UACCESS-safe function");
+		return 1;
+	}
+
+	if (state->df) {
+		WARN_INSN(insn, "return with DF set");
+		return 1;
+	}
+
+	if (func && has_modified_stack_frame(insn, state)) {
+		WARN_INSN(insn, "return with modified stack frame");
+		return 1;
+	}
+
+	if (state->cfi.bp_scratch) {
+		WARN_INSN(insn, "BP used as a scratch register");
+		return 1;
+	}
+
+	return 0;
+}
+
+static struct instruction *next_insn_to_validate(struct objtool_file *file,
+						 struct instruction *insn)
+{
+	struct alt_group *alt_group = insn->alt_group;
+
+	/*
+	 * Simulate the fact that alternatives are patched in-place.  When the
+	 * end of a replacement alt_group is reached, redirect objtool flow to
+	 * the end of the original alt_group.
+	 *
+	 * insn->alts->insn -> alt_group->first_insn
+	 *		       ...
+	 *		       alt_group->last_insn
+	 *		       [alt_group->nop]      -> next(orig_group->last_insn)
+	 */
+	if (alt_group) {
+		if (alt_group->nop) {
+			/* ->nop implies ->orig_group */
+			if (insn == alt_group->last_insn)
+				return alt_group->nop;
+			if (insn == alt_group->nop)
+				goto next_orig;
+		}
+		if (insn == alt_group->last_insn && alt_group->orig_group)
+			goto next_orig;
+	}
+
+	return next_insn_same_sec(file, insn);
+
+next_orig:
+	return next_insn_same_sec(file, alt_group->orig_group->last_insn);
+}
+
+/*
+ * Follow the branch starting at the given instruction, and recursively follow
+ * any other branches (jumps).  Meanwhile, track the frame pointer state at
+ * each instruction and validate all the rules described in
+ * tools/objtool/Documentation/objtool.txt.
+ */
+static int validate_branch(struct objtool_file *file, struct symbol *func,
+			   struct instruction *insn, struct insn_state state)
+{
+	struct alternative *alt;
+	struct instruction *next_insn, *prev_insn = NULL;
+	struct section *sec;
+	u8 visited;
+	int ret;
+
+	sec = insn->sec;
+
+	while (1) {
+		next_insn = next_insn_to_validate(file, insn);
+
+		if (func && insn_func(insn) && func != insn_func(insn)->pfunc) {
+			/* Ignore KCFI type preambles, which always fall through */
+			if (!strncmp(func->name, "__cfi_", 6) ||
+			    !strncmp(func->name, "__pfx_", 6))
+				return 0;
+
+			WARN("%s() falls through to next function %s()",
+			     func->name, insn_func(insn)->name);
+			return 1;
+		}
+
+		if (func && insn->ignore) {
+			WARN_INSN(insn, "BUG: why am I validating an ignored function?");
+			return 1;
+		}
+
+		visited = VISITED_BRANCH << state.uaccess;
+		if (insn->visited & VISITED_BRANCH_MASK) {
+			if (!insn->hint && !insn_cfi_match(insn, &state.cfi))
+				return 1;
+
+			if (insn->visited & visited)
+				return 0;
+		} else {
+			nr_insns_visited++;
+		}
+
+		if (state.noinstr)
+			state.instr += insn->instr;
+
+		if (insn->hint) {
+			if (insn->restore) {
+				struct instruction *save_insn, *i;
+
+				i = insn;
+				save_insn = NULL;
+
+				sym_for_each_insn_continue_reverse(file, func, i) {
+					if (i->save) {
+						save_insn = i;
+						break;
+					}
+				}
+
+				if (!save_insn) {
+					WARN_INSN(insn, "no corresponding CFI save for CFI restore");
+					return 1;
+				}
+
+				if (!save_insn->visited) {
+					WARN_INSN(insn, "objtool isn't smart enough to handle this CFI save/restore combo");
+					return 1;
+				}
+
+				insn->cfi = save_insn->cfi;
+				nr_cfi_reused++;
+			}
+
+			state.cfi = *insn->cfi;
+		} else {
+			/* XXX track if we actually changed state.cfi */
+
+			if (prev_insn && !cficmp(prev_insn->cfi, &state.cfi)) {
+				insn->cfi = prev_insn->cfi;
+				nr_cfi_reused++;
+			} else {
+				insn->cfi = cfi_hash_find_or_add(&state.cfi);
+			}
+		}
+
+		insn->visited |= visited;
+
+		if (propagate_alt_cfi(file, insn))
+			return 1;
+
+		if (!insn->ignore_alts && insn->alts) {
+			bool skip_orig = false;
+
+			for (alt = insn->alts; alt; alt = alt->next) {
+				if (alt->skip_orig)
+					skip_orig = true;
+
+				ret = validate_branch(file, func, alt->insn, state);
+				if (ret) {
+					BT_INSN(insn, "(alt)");
+					return ret;
+				}
+			}
+
+			if (skip_orig)
+				return 0;
+		}
+
+		if (handle_insn_ops(insn, next_insn, &state))
+			return 1;
+
+		switch (insn->type) {
+
+		case INSN_RETURN:
+			return validate_return(func, insn, &state);
+
+		case INSN_CALL:
+		case INSN_CALL_DYNAMIC:
+			ret = validate_call(file, insn, &state);
+			if (ret)
+				return ret;
+
+			if (opts.stackval && func && !is_special_call(insn) &&
+			    !has_valid_stack_frame(&state)) {
+				WARN_INSN(insn, "call without frame pointer save/setup");
+				return 1;
+			}
+
+			if (insn->dead_end)
+				return 0;
+
+			break;
+
+		case INSN_JUMP_CONDITIONAL:
+		case INSN_JUMP_UNCONDITIONAL:
+			if (is_sibling_call(insn)) {
+				ret = validate_sibling_call(file, insn, &state);
+				if (ret)
+					return ret;
+
+			} else if (insn->jump_dest) {
+				ret = validate_branch(file, func,
+						      insn->jump_dest, state);
+				if (ret) {
+					BT_INSN(insn, "(branch)");
+					return ret;
+				}
+			}
+
+			if (insn->type == INSN_JUMP_UNCONDITIONAL)
+				return 0;
+
+			break;
+
+		case INSN_JUMP_DYNAMIC:
+		case INSN_JUMP_DYNAMIC_CONDITIONAL:
+			if (is_sibling_call(insn)) {
+				ret = validate_sibling_call(file, insn, &state);
+				if (ret)
+					return ret;
+			}
+
+			if (insn->type == INSN_JUMP_DYNAMIC)
+				return 0;
+
+			break;
+
+		case INSN_CONTEXT_SWITCH:
+			if (func && (!next_insn || !next_insn->hint)) {
+				WARN_INSN(insn, "unsupported instruction in callable function");
+				return 1;
+			}
+			return 0;
+
+		case INSN_STAC:
+			if (state.uaccess) {
+				WARN_INSN(insn, "recursive UACCESS enable");
+				return 1;
+			}
+
+			state.uaccess = true;
+			break;
+
+		case INSN_CLAC:
+			if (!state.uaccess && func) {
+				WARN_INSN(insn, "redundant UACCESS disable");
+				return 1;
+			}
+
+			if (func_uaccess_safe(func) && !state.uaccess_stack) {
+				WARN_INSN(insn, "UACCESS-safe disables UACCESS");
+				return 1;
+			}
+
+			state.uaccess = false;
+			break;
+
+		case INSN_STD:
+			if (state.df) {
+				WARN_INSN(insn, "recursive STD");
+				return 1;
+			}
+
+			state.df = true;
+			break;
+
+		case INSN_CLD:
+			if (!state.df && func) {
+				WARN_INSN(insn, "redundant CLD");
+				return 1;
+			}
+
+			state.df = false;
+			break;
+
+		default:
+			break;
+		}
+
+		if (insn->dead_end)
+			return 0;
+
+		if (!next_insn) {
+			if (state.cfi.cfa.base == CFI_UNDEFINED)
+				return 0;
+			WARN("%s: unexpected end of section", sec->name);
+			return 1;
+		}
+
+		prev_insn = insn;
+		insn = next_insn;
+	}
+
+	return 0;
+}
+
+static int validate_unwind_hint(struct objtool_file *file,
+				  struct instruction *insn,
+				  struct insn_state *state)
+{
+	if (insn->hint && !insn->visited && !insn->ignore) {
+		int ret = validate_branch(file, insn_func(insn), insn, *state);
+		if (ret)
+			BT_INSN(insn, "<=== (hint)");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int validate_unwind_hints(struct objtool_file *file, struct section *sec)
+{
+	struct instruction *insn;
+	struct insn_state state;
+	int warnings = 0;
+
+	if (!file->hints)
+		return 0;
+
+	init_insn_state(file, &state, sec);
+
+	if (sec) {
+		sec_for_each_insn(file, sec, insn)
+			warnings += validate_unwind_hint(file, insn, &state);
+	} else {
+		for_each_insn(file, insn)
+			warnings += validate_unwind_hint(file, insn, &state);
+	}
+
+	return warnings;
+}
+
+/*
+ * Validate rethunk entry constraint: must untrain RET before the first RET.
+ *
+ * Follow every branch (intra-function) and ensure VALIDATE_UNRET_END comes
+ * before an actual RET instruction.
+ */
+static int validate_unret(struct objtool_file *file, struct instruction *insn)
+{
+	struct instruction *next, *dest;
+	int ret;
+
+	for (;;) {
+		next = next_insn_to_validate(file, insn);
+
+		if (insn->visited & VISITED_UNRET)
+			return 0;
+
+		insn->visited |= VISITED_UNRET;
+
+		if (!insn->ignore_alts && insn->alts) {
+			struct alternative *alt;
+			bool skip_orig = false;
+
+			for (alt = insn->alts; alt; alt = alt->next) {
+				if (alt->skip_orig)
+					skip_orig = true;
+
+				ret = validate_unret(file, alt->insn);
+				if (ret) {
+					BT_INSN(insn, "(alt)");
+					return ret;
+				}
+			}
+
+			if (skip_orig)
+				return 0;
+		}
+
+		switch (insn->type) {
+
+		case INSN_CALL_DYNAMIC:
+		case INSN_JUMP_DYNAMIC:
+		case INSN_JUMP_DYNAMIC_CONDITIONAL:
+			WARN_INSN(insn, "early indirect call");
+			return 1;
+
+		case INSN_JUMP_UNCONDITIONAL:
+		case INSN_JUMP_CONDITIONAL:
+			if (!is_sibling_call(insn)) {
+				if (!insn->jump_dest) {
+					WARN_INSN(insn, "unresolved jump target after linking?!?");
+					return -1;
+				}
+				ret = validate_unret(file, insn->jump_dest);
+				if (ret) {
+					BT_INSN(insn, "(branch%s)",
+						insn->type == INSN_JUMP_CONDITIONAL ? "-cond" : "");
+					return ret;
+				}
+
+				if (insn->type == INSN_JUMP_UNCONDITIONAL)
+					return 0;
+
+				break;
+			}
+
+			/* fallthrough */
+		case INSN_CALL:
+			dest = find_insn(file, insn_call_dest(insn)->sec,
+					 insn_call_dest(insn)->offset);
+			if (!dest) {
+				WARN("Unresolved function after linking!?: %s",
+				     insn_call_dest(insn)->name);
+				return -1;
+			}
+
+			ret = validate_unret(file, dest);
+			if (ret) {
+				BT_INSN(insn, "(call)");
+				return ret;
+			}
+			/*
+			 * If a call returns without error, it must have seen UNTRAIN_RET.
+			 * Therefore any non-error return is a success.
+			 */
+			return 0;
+
+		case INSN_RETURN:
+			WARN_INSN(insn, "RET before UNTRAIN");
+			return 1;
+
+		case INSN_NOP:
+			if (insn->retpoline_safe)
+				return 0;
+			break;
+
+		default:
+			break;
+		}
+
+		if (!next) {
+			WARN_INSN(insn, "teh end!");
+			return -1;
+		}
+		insn = next;
+	}
+
+	return 0;
+}
+
+/*
+ * Validate that all branches starting at VALIDATE_UNRET_BEGIN encounter
+ * VALIDATE_UNRET_END before RET.
+ */
+static int validate_unrets(struct objtool_file *file)
+{
+	struct instruction *insn;
+	int ret, warnings = 0;
+
+	for_each_insn(file, insn) {
+		if (!insn->unret)
+			continue;
+
+		ret = validate_unret(file, insn);
+		if (ret < 0) {
+			WARN_INSN(insn, "Failed UNRET validation");
+			return ret;
+		}
+		warnings += ret;
+	}
+
+	return warnings;
+}
+
+static int validate_retpoline(struct objtool_file *file)
+{
+	struct instruction *insn;
+	int warnings = 0;
+
+	for_each_insn(file, insn) {
+		if (insn->type != INSN_JUMP_DYNAMIC &&
+		    insn->type != INSN_CALL_DYNAMIC &&
+		    insn->type != INSN_RETURN)
+			continue;
+
+		if (insn->retpoline_safe)
+			continue;
+
+		if (insn->sec->init)
+			continue;
+
+		if (insn->type == INSN_RETURN) {
+			if (opts.rethunk) {
+				WARN_INSN(insn, "'naked' return found in RETHUNK build");
+			} else
+				continue;
+		} else {
+			WARN_INSN(insn, "indirect %s found in RETPOLINE build",
+				  insn->type == INSN_JUMP_DYNAMIC ? "jump" : "call");
+		}
+
+		warnings++;
+	}
+
+	return warnings;
+}
+
+static bool is_kasan_insn(struct instruction *insn)
+{
+	return (insn->type == INSN_CALL &&
+		!strcmp(insn_call_dest(insn)->name, "__asan_handle_no_return"));
+}
+
+static bool is_ubsan_insn(struct instruction *insn)
+{
+	return (insn->type == INSN_CALL &&
+		!strcmp(insn_call_dest(insn)->name,
+			"__ubsan_handle_builtin_unreachable"));
+}
+
+static bool ignore_unreachable_insn(struct objtool_file *file, struct instruction *insn)
+{
+	int i;
+	struct instruction *prev_insn;
+
+	if (insn->ignore || insn->type == INSN_NOP || insn->type == INSN_TRAP)
+		return true;
+
+	/*
+	 * Ignore alternative replacement instructions.  This can happen
+	 * when a whitelisted function uses one of the ALTERNATIVE macros.
+	 */
+	if (!strcmp(insn->sec->name, ".altinstr_replacement") ||
+	    !strcmp(insn->sec->name, ".altinstr_aux"))
+		return true;
+
+	/*
+	 * Whole archive runs might encounter dead code from weak symbols.
+	 * This is where the linker will have dropped the weak symbol in
+	 * favour of a regular symbol, but leaves the code in place.
+	 *
+	 * In this case we'll find a piece of code (whole function) that is not
+	 * covered by a !section symbol. Ignore them.
+	 */
+	if (opts.link && !insn_func(insn)) {
+		int size = find_symbol_hole_containing(insn->sec, insn->offset);
+		unsigned long end = insn->offset + size;
+
+		if (!size) /* not a hole */
+			return false;
+
+		if (size < 0) /* hole until the end */
+			return true;
+
+		sec_for_each_insn_continue(file, insn) {
+			/*
+			 * If we reach a visited instruction at or before the
+			 * end of the hole, ignore the unreachable.
+			 */
+			if (insn->visited)
+				return true;
+
+			if (insn->offset >= end)
+				break;
+
+			/*
+			 * If this hole jumps to a .cold function, mark it ignore too.
+			 */
+			if (insn->jump_dest && insn_func(insn->jump_dest) &&
+			    strstr(insn_func(insn->jump_dest)->name, ".cold")) {
+				struct instruction *dest = insn->jump_dest;
+				func_for_each_insn(file, insn_func(dest), dest)
+					dest->ignore = true;
+			}
+		}
+
+		return false;
+	}
+
+	if (!insn_func(insn))
+		return false;
+
+	if (insn_func(insn)->static_call_tramp)
+		return true;
+
+	/*
+	 * CONFIG_UBSAN_TRAP inserts a UD2 when it sees
+	 * __builtin_unreachable().  The BUG() macro has an unreachable() after
+	 * the UD2, which causes GCC's undefined trap logic to emit another UD2
+	 * (or occasionally a JMP to UD2).
+	 *
+	 * It may also insert a UD2 after calling a __noreturn function.
+	 */
+	prev_insn = prev_insn_same_sec(file, insn);
+	if (prev_insn->dead_end &&
+	    (insn->type == INSN_BUG ||
+	     (insn->type == INSN_JUMP_UNCONDITIONAL &&
+	      insn->jump_dest && insn->jump_dest->type == INSN_BUG)))
+		return true;
+
+	/*
+	 * Check if this (or a subsequent) instruction is related to
+	 * CONFIG_UBSAN or CONFIG_KASAN.
+	 *
+	 * End the search at 5 instructions to avoid going into the weeds.
+	 */
+	for (i = 0; i < 5; i++) {
+
+		if (is_kasan_insn(insn) || is_ubsan_insn(insn))
+			return true;
+
+		if (insn->type == INSN_JUMP_UNCONDITIONAL) {
+			if (insn->jump_dest &&
+			    insn_func(insn->jump_dest) == insn_func(insn)) {
+				insn = insn->jump_dest;
+				continue;
+			}
+
+			break;
+		}
+
+		if (insn->offset + insn->len >= insn_func(insn)->offset + insn_func(insn)->len)
+			break;
+
+		insn = next_insn_same_sec(file, insn);
+	}
+
+	return false;
+}
+
+static int add_prefix_symbol(struct objtool_file *file, struct symbol *func)
+{
+	struct instruction *insn, *prev;
+	struct cfi_state *cfi;
+
+	insn = find_insn(file, func->sec, func->offset);
+	if (!insn)
+		return -1;
+
+	for (prev = prev_insn_same_sec(file, insn);
+	     prev;
+	     prev = prev_insn_same_sec(file, prev)) {
+		u64 offset;
+
+		if (prev->type != INSN_NOP)
+			return -1;
+
+		offset = func->offset - prev->offset;
+
+		if (offset > opts.prefix)
+			return -1;
+
+		if (offset < opts.prefix)
+			continue;
+
+		elf_create_prefix_symbol(file->elf, func, opts.prefix);
+		break;
+	}
+
+	if (!prev)
+		return -1;
+
+	if (!insn->cfi) {
+		/*
+		 * This can happen if stack validation isn't enabled or the
+		 * function is annotated with STACK_FRAME_NON_STANDARD.
+		 */
+		return 0;
+	}
+
+	/* Propagate insn->cfi to the prefix code */
+	cfi = cfi_hash_find_or_add(insn->cfi);
+	for (; prev != insn; prev = next_insn_same_sec(file, prev))
+		prev->cfi = cfi;
+
+	return 0;
+}
+
+static int add_prefix_symbols(struct objtool_file *file)
+{
+	struct section *sec;
+	struct symbol *func;
+
+	for_each_sec(file, sec) {
+		if (!(sec->sh.sh_flags & SHF_EXECINSTR))
+			continue;
+
+		sec_for_each_sym(sec, func) {
+			if (func->type != STT_FUNC)
+				continue;
+
+			add_prefix_symbol(file, func);
+		}
+	}
+
+	return 0;
+}
+
+static int validate_symbol(struct objtool_file *file, struct section *sec,
+			   struct symbol *sym, struct insn_state *state)
+{
+	struct instruction *insn;
+	int ret;
+
+	if (!sym->len) {
+		WARN("%s() is missing an ELF size annotation", sym->name);
+		return 1;
+	}
+
+	if (sym->pfunc != sym || sym->alias != sym)
+		return 0;
+
+	insn = find_insn(file, sec, sym->offset);
+	if (!insn || insn->ignore || insn->visited)
+		return 0;
+
+	state->uaccess = sym->uaccess_safe;
+
+	ret = validate_branch(file, insn_func(insn), insn, *state);
+	if (ret)
+		BT_INSN(insn, "<=== (sym)");
+	return ret;
+}
+
+static int validate_section(struct objtool_file *file, struct section *sec)
+{
+	struct insn_state state;
+	struct symbol *func;
+	int warnings = 0;
+
+	sec_for_each_sym(sec, func) {
+		if (func->type != STT_FUNC)
+			continue;
+
+		init_insn_state(file, &state, sec);
+		set_func_state(&state.cfi);
+
+		warnings += validate_symbol(file, sec, func, &state);
+	}
+
+	return warnings;
+}
+
+static int validate_noinstr_sections(struct objtool_file *file)
+{
+	struct section *sec;
+	int warnings = 0;
+
+	sec = find_section_by_name(file->elf, ".noinstr.text");
+	if (sec) {
+		warnings += validate_section(file, sec);
+		warnings += validate_unwind_hints(file, sec);
+	}
+
+	sec = find_section_by_name(file->elf, ".entry.text");
+	if (sec) {
+		warnings += validate_section(file, sec);
+		warnings += validate_unwind_hints(file, sec);
+	}
+
+	sec = find_section_by_name(file->elf, ".cpuidle.text");
+	if (sec) {
+		warnings += validate_section(file, sec);
+		warnings += validate_unwind_hints(file, sec);
+	}
+
+	return warnings;
+}
+
+static int validate_functions(struct objtool_file *file)
+{
+	struct section *sec;
+	int warnings = 0;
+
+	for_each_sec(file, sec) {
+		if (!(sec->sh.sh_flags & SHF_EXECINSTR))
+			continue;
+
+		warnings += validate_section(file, sec);
+	}
+
+	return warnings;
+}
+
+static void mark_endbr_used(struct instruction *insn)
+{
+	if (!list_empty(&insn->call_node))
+		list_del_init(&insn->call_node);
+}
+
+static bool noendbr_range(struct objtool_file *file, struct instruction *insn)
+{
+	struct symbol *sym = find_symbol_containing(insn->sec, insn->offset-1);
+	struct instruction *first;
+
+	if (!sym)
+		return false;
+
+	first = find_insn(file, sym->sec, sym->offset);
+	if (!first)
+		return false;
+
+	if (first->type != INSN_ENDBR && !first->noendbr)
+		return false;
+
+	return insn->offset == sym->offset + sym->len;
+}
+
+static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn)
+{
+	struct instruction *dest;
+	struct reloc *reloc;
+	unsigned long off;
+	int warnings = 0;
+
+	/*
+	 * Looking for function pointer load relocations.  Ignore
+	 * direct/indirect branches:
+	 */
+	switch (insn->type) {
+	case INSN_CALL:
+	case INSN_CALL_DYNAMIC:
+	case INSN_JUMP_CONDITIONAL:
+	case INSN_JUMP_UNCONDITIONAL:
+	case INSN_JUMP_DYNAMIC:
+	case INSN_JUMP_DYNAMIC_CONDITIONAL:
+	case INSN_RETURN:
+	case INSN_NOP:
+		return 0;
+	default:
+		break;
+	}
+
+	for (reloc = insn_reloc(file, insn);
+	     reloc;
+	     reloc = find_reloc_by_dest_range(file->elf, insn->sec,
+					      reloc_offset(reloc) + 1,
+					      (insn->offset + insn->len) - (reloc_offset(reloc) + 1))) {
+
+		/*
+		 * static_call_update() references the trampoline, which
+		 * doesn't have (or need) ENDBR.  Skip warning in that case.
+		 */
+		if (reloc->sym->static_call_tramp)
+			continue;
+
+		off = reloc->sym->offset;
+		if (reloc_type(reloc) == R_X86_64_PC32 ||
+		    reloc_type(reloc) == R_X86_64_PLT32)
+			off += arch_dest_reloc_offset(reloc_addend(reloc));
+		else
+			off += reloc_addend(reloc);
+
+		dest = find_insn(file, reloc->sym->sec, off);
+		if (!dest)
+			continue;
+
+		if (dest->type == INSN_ENDBR) {
+			mark_endbr_used(dest);
+			continue;
+		}
+
+		if (insn_func(dest) && insn_func(insn) &&
+		    insn_func(dest)->pfunc == insn_func(insn)->pfunc) {
+			/*
+			 * Anything from->to self is either _THIS_IP_ or
+			 * IRET-to-self.
+			 *
+			 * There is no sane way to annotate _THIS_IP_ since the
+			 * compiler treats the relocation as a constant and is
+			 * happy to fold in offsets, skewing any annotation we
+			 * do, leading to vast amounts of false-positives.
+			 *
+			 * There's also compiler generated _THIS_IP_ through
+			 * KCOV and such which we have no hope of annotating.
+			 *
+			 * As such, blanket accept self-references without
+			 * issue.
+			 */
+			continue;
+		}
+
+		/*
+		 * Accept anything ANNOTATE_NOENDBR.
+		 */
+		if (dest->noendbr)
+			continue;
+
+		/*
+		 * Accept if this is the instruction after a symbol
+		 * that is (no)endbr -- typical code-range usage.
+		 */
+		if (noendbr_range(file, dest))
+			continue;
+
+		WARN_INSN(insn, "relocation to !ENDBR: %s", offstr(dest->sec, dest->offset));
+
+		warnings++;
+	}
+
+	return warnings;
+}
+
+static int validate_ibt_data_reloc(struct objtool_file *file,
+				   struct reloc *reloc)
+{
+	struct instruction *dest;
+
+	dest = find_insn(file, reloc->sym->sec,
+			 reloc->sym->offset + reloc_addend(reloc));
+	if (!dest)
+		return 0;
+
+	if (dest->type == INSN_ENDBR) {
+		mark_endbr_used(dest);
+		return 0;
+	}
+
+	if (dest->noendbr)
+		return 0;
+
+	WARN_FUNC("data relocation to !ENDBR: %s",
+		  reloc->sec->base, reloc_offset(reloc),
+		  offstr(dest->sec, dest->offset));
+
+	return 1;
+}
+
+/*
+ * Validate IBT rules and remove used ENDBR instructions from the seal list.
+ * Unused ENDBR instructions will be annotated for sealing (i.e., replaced with
+ * NOPs) later, in create_ibt_endbr_seal_sections().
+ */
+static int validate_ibt(struct objtool_file *file)
+{
+	struct section *sec;
+	struct reloc *reloc;
+	struct instruction *insn;
+	int warnings = 0;
+
+	for_each_insn(file, insn)
+		warnings += validate_ibt_insn(file, insn);
+
+	for_each_sec(file, sec) {
+
+		/* Already done by validate_ibt_insn() */
+		if (sec->sh.sh_flags & SHF_EXECINSTR)
+			continue;
+
+		if (!sec->rsec)
+			continue;
+
+		/*
+		 * These sections can reference text addresses, but not with
+		 * the intent to indirect branch to them.
+		 */
+		if ((!strncmp(sec->name, ".discard", 8) &&
+		     strcmp(sec->name, ".discard.ibt_endbr_noseal"))	||
+		    !strncmp(sec->name, ".debug", 6)			||
+		    !strcmp(sec->name, ".altinstructions")		||
+		    !strcmp(sec->name, ".ibt_endbr_seal")		||
+		    !strcmp(sec->name, ".orc_unwind_ip")		||
+		    !strcmp(sec->name, ".parainstructions")		||
+		    !strcmp(sec->name, ".retpoline_sites")		||
+		    !strcmp(sec->name, ".smp_locks")			||
+		    !strcmp(sec->name, ".static_call_sites")		||
+		    !strcmp(sec->name, "_error_injection_whitelist")	||
+		    !strcmp(sec->name, "_kprobe_blacklist")		||
+		    !strcmp(sec->name, "__bug_table")			||
+		    !strcmp(sec->name, "__ex_table")			||
+		    !strcmp(sec->name, "__jump_table")			||
+		    !strcmp(sec->name, "__mcount_loc")			||
+		    !strcmp(sec->name, ".kcfi_traps")			||
+		    strstr(sec->name, "__patchable_function_entries"))
+			continue;
+
+		for_each_reloc(sec->rsec, reloc)
+			warnings += validate_ibt_data_reloc(file, reloc);
+	}
+
+	return warnings;
+}
+
+static int validate_sls(struct objtool_file *file)
+{
+	struct instruction *insn, *next_insn;
+	int warnings = 0;
+
+	for_each_insn(file, insn) {
+		next_insn = next_insn_same_sec(file, insn);
+
+		if (insn->retpoline_safe)
+			continue;
+
+		switch (insn->type) {
+		case INSN_RETURN:
+			if (!next_insn || next_insn->type != INSN_TRAP) {
+				WARN_INSN(insn, "missing int3 after ret");
+				warnings++;
+			}
+
+			break;
+		case INSN_JUMP_DYNAMIC:
+			if (!next_insn || next_insn->type != INSN_TRAP) {
+				WARN_INSN(insn, "missing int3 after indirect jump");
+				warnings++;
+			}
+			break;
+		default:
+			break;
+		}
+	}
+
+	return warnings;
+}
+
+static bool ignore_noreturn_call(struct instruction *insn)
+{
+	struct symbol *call_dest = insn_call_dest(insn);
+
+	/*
+	 * FIXME: hack, we need a real noreturn solution
+	 *
+	 * Problem is, exc_double_fault() may or may not return, depending on
+	 * whether CONFIG_X86_ESPFIX64 is set.  But objtool has no visibility
+	 * to the kernel config.
+	 *
+	 * Other potential ways to fix it:
+	 *
+	 *   - have compiler communicate __noreturn functions somehow
+	 *   - remove CONFIG_X86_ESPFIX64
+	 *   - read the .config file
+	 *   - add a cmdline option
+	 *   - create a generic objtool annotation format (vs a bunch of custom
+	 *     formats) and annotate it
+	 */
+	if (!strcmp(call_dest->name, "exc_double_fault")) {
+		/* prevent further unreachable warnings for the caller */
+		insn->sym->warned = 1;
+		return true;
+	}
+
+	return false;
+}
+
+static int validate_reachable_instructions(struct objtool_file *file)
+{
+	struct instruction *insn, *prev_insn;
+	struct symbol *call_dest;
+	int warnings = 0;
+
+	if (file->ignore_unreachables)
+		return 0;
+
+	for_each_insn(file, insn) {
+		if (insn->visited || ignore_unreachable_insn(file, insn))
+			continue;
+
+		prev_insn = prev_insn_same_sec(file, insn);
+		if (prev_insn && prev_insn->dead_end) {
+			call_dest = insn_call_dest(prev_insn);
+			if (call_dest && !ignore_noreturn_call(prev_insn)) {
+				WARN_INSN(insn, "%s() is missing a __noreturn annotation",
+					  call_dest->name);
+				warnings++;
+				continue;
+			}
+		}
+
+		WARN_INSN(insn, "unreachable instruction");
+		warnings++;
+	}
+
+	return warnings;
+}
+
+/* 'funcs' is a space-separated list of function names */
+static int disas_funcs(const char *funcs)
+{
+	const char *objdump_str, *cross_compile;
+	int size, ret;
+	char *cmd;
+
+	cross_compile = getenv("CROSS_COMPILE");
+
+	objdump_str = "%sobjdump -wdr %s | gawk -M -v _funcs='%s' '"
+			"BEGIN { split(_funcs, funcs); }"
+			"/^$/ { func_match = 0; }"
+			"/<.*>:/ { "
+				"f = gensub(/.*<(.*)>:/, \"\\\\1\", 1);"
+				"for (i in funcs) {"
+					"if (funcs[i] == f) {"
+						"func_match = 1;"
+						"base = strtonum(\"0x\" $1);"
+						"break;"
+					"}"
+				"}"
+			"}"
+			"{"
+				"if (func_match) {"
+					"addr = strtonum(\"0x\" $1);"
+					"printf(\"%%04x \", addr - base);"
+					"print;"
+				"}"
+			"}' 1>&2";
+
+	/* fake snprintf() to calculate the size */
+	size = snprintf(NULL, 0, objdump_str, cross_compile, objname, funcs) + 1;
+	if (size <= 0) {
+		WARN("objdump string size calculation failed");
+		return -1;
+	}
+
+	cmd = malloc(size);
+
+	/* real snprintf() */
+	snprintf(cmd, size, objdump_str, cross_compile, objname, funcs);
+	ret = system(cmd);
+	if (ret) {
+		WARN("disassembly failed: %d", ret);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int disas_warned_funcs(struct objtool_file *file)
+{
+	struct symbol *sym;
+	char *funcs = NULL, *tmp;
+
+	for_each_sym(file, sym) {
+		if (sym->warned) {
+			if (!funcs) {
+				funcs = malloc(strlen(sym->name) + 1);
+				strcpy(funcs, sym->name);
+			} else {
+				tmp = malloc(strlen(funcs) + strlen(sym->name) + 2);
+				sprintf(tmp, "%s %s", funcs, sym->name);
+				free(funcs);
+				funcs = tmp;
+			}
+		}
+	}
+
+	if (funcs)
+		disas_funcs(funcs);
+
+	return 0;
+}
+
+struct insn_chunk {
+	void *addr;
+	struct insn_chunk *next;
+};
+
+/*
+ * Reduce peak RSS usage by freeing insns memory before writing the ELF file,
+ * which can trigger more allocations for .debug_* sections whose data hasn't
+ * been read yet.
+ */
+static void free_insns(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct insn_chunk *chunks = NULL, *chunk;
+
+	for_each_insn(file, insn) {
+		if (!insn->idx) {
+			chunk = malloc(sizeof(*chunk));
+			chunk->addr = insn;
+			chunk->next = chunks;
+			chunks = chunk;
+		}
+	}
+
+	for (chunk = chunks; chunk; chunk = chunk->next)
+		free(chunk->addr);
+}
+
+int check(struct objtool_file *file)
+{
+	int ret, warnings = 0;
+
+	arch_initial_func_cfi_state(&initial_func_cfi);
+	init_cfi_state(&init_cfi);
+	init_cfi_state(&func_cfi);
+	set_func_state(&func_cfi);
+	init_cfi_state(&force_undefined_cfi);
+	force_undefined_cfi.force_undefined = true;
+
+	if (!cfi_hash_alloc(1UL << (file->elf->symbol_bits - 3)))
+		goto out;
+
+	cfi_hash_add(&init_cfi);
+	cfi_hash_add(&func_cfi);
+
+	ret = decode_sections(file);
+	if (ret < 0)
+		goto out;
+
+	warnings += ret;
+
+	if (!nr_insns)
+		goto out;
+
+	if (opts.retpoline) {
+		ret = validate_retpoline(file);
+		if (ret < 0)
+			return ret;
+		warnings += ret;
+	}
+
+	if (opts.stackval || opts.orc || opts.uaccess) {
+		ret = validate_functions(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+
+		ret = validate_unwind_hints(file, NULL);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+
+		if (!warnings) {
+			ret = validate_reachable_instructions(file);
+			if (ret < 0)
+				goto out;
+			warnings += ret;
+		}
+
+	} else if (opts.noinstr) {
+		ret = validate_noinstr_sections(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	if (opts.unret) {
+		/*
+		 * Must be after validate_branch() and friends, it plays
+		 * further games with insn->visited.
+		 */
+		ret = validate_unrets(file);
+		if (ret < 0)
+			return ret;
+		warnings += ret;
+	}
+
+	if (opts.ibt) {
+		ret = validate_ibt(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	if (opts.sls) {
+		ret = validate_sls(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	if (opts.static_call) {
+		ret = create_static_call_sections(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	if (opts.retpoline) {
+		ret = create_retpoline_sites_sections(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	if (opts.cfi) {
+		ret = create_cfi_sections(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	if (opts.rethunk) {
+		ret = create_return_sites_sections(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+
+		if (opts.hack_skylake) {
+			ret = create_direct_call_sections(file);
+			if (ret < 0)
+				goto out;
+			warnings += ret;
+		}
+	}
+
+	if (opts.mcount) {
+		ret = create_mcount_loc_sections(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	if (opts.prefix) {
+		ret = add_prefix_symbols(file);
+		if (ret < 0)
+			return ret;
+		warnings += ret;
+	}
+
+	if (opts.ibt) {
+		ret = create_ibt_endbr_seal_sections(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	if (opts.orc && nr_insns) {
+		ret = orc_create(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	free_insns(file);
+
+	if (opts.verbose)
+		disas_warned_funcs(file);
+
+	if (opts.stats) {
+		printf("nr_insns_visited: %ld\n", nr_insns_visited);
+		printf("nr_cfi: %ld\n", nr_cfi);
+		printf("nr_cfi_reused: %ld\n", nr_cfi_reused);
+		printf("nr_cfi_cache: %ld\n", nr_cfi_cache);
+	}
+
+out:
+	/*
+	 *  For now, don't fail the kernel build on fatal warnings.  These
+	 *  errors are still fairly common due to the growing matrix of
+	 *  supported toolchains and their recent pace of change.
+	 */
+	return 0;
+}
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
new file mode 100644
index 0000000000..081befa467
--- /dev/null
+++ b/tools/objtool/elf.c
@@ -0,0 +1,1353 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * elf.c - ELF access library
+ *
+ * Adapted from kpatch (https://github.com/dynup/kpatch):
+ * Copyright (C) 2013-2015 Josh Poimboeuf <jpoimboe@redhat.com>
+ * Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <linux/interval_tree_generic.h>
+#include <objtool/builtin.h>
+
+#include <objtool/elf.h>
+#include <objtool/warn.h>
+
+#define MAX_NAME_LEN 128
+
+static inline u32 str_hash(const char *str)
+{
+	return jhash(str, strlen(str), 0);
+}
+
+#define __elf_table(name)	(elf->name##_hash)
+#define __elf_bits(name)	(elf->name##_bits)
+
+#define __elf_table_entry(name, key) \
+	__elf_table(name)[hash_min(key, __elf_bits(name))]
+
+#define elf_hash_add(name, node, key)					\
+({									\
+	struct elf_hash_node *__node = node;				\
+	__node->next = __elf_table_entry(name, key);			\
+	__elf_table_entry(name, key) = __node;				\
+})
+
+static inline void __elf_hash_del(struct elf_hash_node *node,
+				  struct elf_hash_node **head)
+{
+	struct elf_hash_node *cur, *prev;
+
+	if (node == *head) {
+		*head = node->next;
+		return;
+	}
+
+	for (prev = NULL, cur = *head; cur; prev = cur, cur = cur->next) {
+		if (cur == node) {
+			prev->next = cur->next;
+			break;
+		}
+	}
+}
+
+#define elf_hash_del(name, node, key) \
+	__elf_hash_del(node, &__elf_table_entry(name, key))
+
+#define elf_list_entry(ptr, type, member)				\
+({									\
+	typeof(ptr) __ptr = (ptr);					\
+	__ptr ? container_of(__ptr, type, member) : NULL;		\
+})
+
+#define elf_hash_for_each_possible(name, obj, member, key)		\
+	for (obj = elf_list_entry(__elf_table_entry(name, key), typeof(*obj), member); \
+	     obj;							\
+	     obj = elf_list_entry(obj->member.next, typeof(*(obj)), member))
+
+#define elf_alloc_hash(name, size) \
+({ \
+	__elf_bits(name) = max(10, ilog2(size)); \
+	__elf_table(name) = mmap(NULL, sizeof(struct elf_hash_node *) << __elf_bits(name), \
+				 PROT_READ|PROT_WRITE, \
+				 MAP_PRIVATE|MAP_ANON, -1, 0); \
+	if (__elf_table(name) == (void *)-1L) { \
+		WARN("mmap fail " #name); \
+		__elf_table(name) = NULL; \
+	} \
+	__elf_table(name); \
+})
+
+static inline unsigned long __sym_start(struct symbol *s)
+{
+	return s->offset;
+}
+
+static inline unsigned long __sym_last(struct symbol *s)
+{
+	return s->offset + s->len - 1;
+}
+
+INTERVAL_TREE_DEFINE(struct symbol, node, unsigned long, __subtree_last,
+		     __sym_start, __sym_last, static, __sym)
+
+#define __sym_for_each(_iter, _tree, _start, _end)			\
+	for (_iter = __sym_iter_first((_tree), (_start), (_end));	\
+	     _iter; _iter = __sym_iter_next(_iter, (_start), (_end)))
+
+struct symbol_hole {
+	unsigned long key;
+	const struct symbol *sym;
+};
+
+/*
+ * Find !section symbol where @offset is after it.
+ */
+static int symbol_hole_by_offset(const void *key, const struct rb_node *node)
+{
+	const struct symbol *s = rb_entry(node, struct symbol, node);
+	struct symbol_hole *sh = (void *)key;
+
+	if (sh->key < s->offset)
+		return -1;
+
+	if (sh->key >= s->offset + s->len) {
+		if (s->type != STT_SECTION)
+			sh->sym = s;
+		return 1;
+	}
+
+	return 0;
+}
+
+struct section *find_section_by_name(const struct elf *elf, const char *name)
+{
+	struct section *sec;
+
+	elf_hash_for_each_possible(section_name, sec, name_hash, str_hash(name)) {
+		if (!strcmp(sec->name, name))
+			return sec;
+	}
+
+	return NULL;
+}
+
+static struct section *find_section_by_index(struct elf *elf,
+					     unsigned int idx)
+{
+	struct section *sec;
+
+	elf_hash_for_each_possible(section, sec, hash, idx) {
+		if (sec->idx == idx)
+			return sec;
+	}
+
+	return NULL;
+}
+
+static struct symbol *find_symbol_by_index(struct elf *elf, unsigned int idx)
+{
+	struct symbol *sym;
+
+	elf_hash_for_each_possible(symbol, sym, hash, idx) {
+		if (sym->idx == idx)
+			return sym;
+	}
+
+	return NULL;
+}
+
+struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset)
+{
+	struct rb_root_cached *tree = (struct rb_root_cached *)&sec->symbol_tree;
+	struct symbol *iter;
+
+	__sym_for_each(iter, tree, offset, offset) {
+		if (iter->offset == offset && iter->type != STT_SECTION)
+			return iter;
+	}
+
+	return NULL;
+}
+
+struct symbol *find_func_by_offset(struct section *sec, unsigned long offset)
+{
+	struct rb_root_cached *tree = (struct rb_root_cached *)&sec->symbol_tree;
+	struct symbol *iter;
+
+	__sym_for_each(iter, tree, offset, offset) {
+		if (iter->offset == offset && iter->type == STT_FUNC)
+			return iter;
+	}
+
+	return NULL;
+}
+
+struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset)
+{
+	struct rb_root_cached *tree = (struct rb_root_cached *)&sec->symbol_tree;
+	struct symbol *iter;
+
+	__sym_for_each(iter, tree, offset, offset) {
+		if (iter->type != STT_SECTION)
+			return iter;
+	}
+
+	return NULL;
+}
+
+/*
+ * Returns size of hole starting at @offset.
+ */
+int find_symbol_hole_containing(const struct section *sec, unsigned long offset)
+{
+	struct symbol_hole hole = {
+		.key = offset,
+		.sym = NULL,
+	};
+	struct rb_node *n;
+	struct symbol *s;
+
+	/*
+	 * Find the rightmost symbol for which @offset is after it.
+	 */
+	n = rb_find(&hole, &sec->symbol_tree.rb_root, symbol_hole_by_offset);
+
+	/* found a symbol that contains @offset */
+	if (n)
+		return 0; /* not a hole */
+
+	/* didn't find a symbol for which @offset is after it */
+	if (!hole.sym)
+		return 0; /* not a hole */
+
+	/* @offset >= sym->offset + sym->len, find symbol after it */
+	n = rb_next(&hole.sym->node);
+	if (!n)
+		return -1; /* until end of address space */
+
+	/* hole until start of next symbol */
+	s = rb_entry(n, struct symbol, node);
+	return s->offset - offset;
+}
+
+struct symbol *find_func_containing(struct section *sec, unsigned long offset)
+{
+	struct rb_root_cached *tree = (struct rb_root_cached *)&sec->symbol_tree;
+	struct symbol *iter;
+
+	__sym_for_each(iter, tree, offset, offset) {
+		if (iter->type == STT_FUNC)
+			return iter;
+	}
+
+	return NULL;
+}
+
+struct symbol *find_symbol_by_name(const struct elf *elf, const char *name)
+{
+	struct symbol *sym;
+
+	elf_hash_for_each_possible(symbol_name, sym, name_hash, str_hash(name)) {
+		if (!strcmp(sym->name, name))
+			return sym;
+	}
+
+	return NULL;
+}
+
+struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
+				     unsigned long offset, unsigned int len)
+{
+	struct reloc *reloc, *r = NULL;
+	struct section *rsec;
+	unsigned long o;
+
+	rsec = sec->rsec;
+	if (!rsec)
+		return NULL;
+
+	for_offset_range(o, offset, offset + len) {
+		elf_hash_for_each_possible(reloc, reloc, hash,
+					   sec_offset_hash(rsec, o)) {
+			if (reloc->sec != rsec)
+				continue;
+
+			if (reloc_offset(reloc) >= offset &&
+			    reloc_offset(reloc) < offset + len) {
+				if (!r || reloc_offset(reloc) < reloc_offset(r))
+					r = reloc;
+			}
+		}
+		if (r)
+			return r;
+	}
+
+	return NULL;
+}
+
+struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset)
+{
+	return find_reloc_by_dest_range(elf, sec, offset, 1);
+}
+
+static bool is_dwarf_section(struct section *sec)
+{
+	return !strncmp(sec->name, ".debug_", 7);
+}
+
+static int read_sections(struct elf *elf)
+{
+	Elf_Scn *s = NULL;
+	struct section *sec;
+	size_t shstrndx, sections_nr;
+	int i;
+
+	if (elf_getshdrnum(elf->elf, &sections_nr)) {
+		WARN_ELF("elf_getshdrnum");
+		return -1;
+	}
+
+	if (elf_getshdrstrndx(elf->elf, &shstrndx)) {
+		WARN_ELF("elf_getshdrstrndx");
+		return -1;
+	}
+
+	if (!elf_alloc_hash(section, sections_nr) ||
+	    !elf_alloc_hash(section_name, sections_nr))
+		return -1;
+
+	elf->section_data = calloc(sections_nr, sizeof(*sec));
+	if (!elf->section_data) {
+		perror("calloc");
+		return -1;
+	}
+	for (i = 0; i < sections_nr; i++) {
+		sec = &elf->section_data[i];
+
+		INIT_LIST_HEAD(&sec->symbol_list);
+
+		s = elf_getscn(elf->elf, i);
+		if (!s) {
+			WARN_ELF("elf_getscn");
+			return -1;
+		}
+
+		sec->idx = elf_ndxscn(s);
+
+		if (!gelf_getshdr(s, &sec->sh)) {
+			WARN_ELF("gelf_getshdr");
+			return -1;
+		}
+
+		sec->name = elf_strptr(elf->elf, shstrndx, sec->sh.sh_name);
+		if (!sec->name) {
+			WARN_ELF("elf_strptr");
+			return -1;
+		}
+
+		if (sec->sh.sh_size != 0 && !is_dwarf_section(sec)) {
+			sec->data = elf_getdata(s, NULL);
+			if (!sec->data) {
+				WARN_ELF("elf_getdata");
+				return -1;
+			}
+			if (sec->data->d_off != 0 ||
+			    sec->data->d_size != sec->sh.sh_size) {
+				WARN("unexpected data attributes for %s",
+				     sec->name);
+				return -1;
+			}
+		}
+
+		list_add_tail(&sec->list, &elf->sections);
+		elf_hash_add(section, &sec->hash, sec->idx);
+		elf_hash_add(section_name, &sec->name_hash, str_hash(sec->name));
+
+		if (is_reloc_sec(sec))
+			elf->num_relocs += sec_num_entries(sec);
+	}
+
+	if (opts.stats) {
+		printf("nr_sections: %lu\n", (unsigned long)sections_nr);
+		printf("section_bits: %d\n", elf->section_bits);
+	}
+
+	/* sanity check, one more call to elf_nextscn() should return NULL */
+	if (elf_nextscn(elf->elf, s)) {
+		WARN("section entry mismatch");
+		return -1;
+	}
+
+	return 0;
+}
+
+static void elf_add_symbol(struct elf *elf, struct symbol *sym)
+{
+	struct list_head *entry;
+	struct rb_node *pnode;
+	struct symbol *iter;
+
+	INIT_LIST_HEAD(&sym->pv_target);
+	sym->alias = sym;
+
+	sym->type = GELF_ST_TYPE(sym->sym.st_info);
+	sym->bind = GELF_ST_BIND(sym->sym.st_info);
+
+	if (sym->type == STT_FILE)
+		elf->num_files++;
+
+	sym->offset = sym->sym.st_value;
+	sym->len = sym->sym.st_size;
+
+	__sym_for_each(iter, &sym->sec->symbol_tree, sym->offset, sym->offset) {
+		if (iter->offset == sym->offset && iter->type == sym->type)
+			iter->alias = sym;
+	}
+
+	__sym_insert(sym, &sym->sec->symbol_tree);
+	pnode = rb_prev(&sym->node);
+	if (pnode)
+		entry = &rb_entry(pnode, struct symbol, node)->list;
+	else
+		entry = &sym->sec->symbol_list;
+	list_add(&sym->list, entry);
+	elf_hash_add(symbol, &sym->hash, sym->idx);
+	elf_hash_add(symbol_name, &sym->name_hash, str_hash(sym->name));
+
+	/*
+	 * Don't store empty STT_NOTYPE symbols in the rbtree.  They
+	 * can exist within a function, confusing the sorting.
+	 */
+	if (!sym->len)
+		__sym_remove(sym, &sym->sec->symbol_tree);
+}
+
+static int read_symbols(struct elf *elf)
+{
+	struct section *symtab, *symtab_shndx, *sec;
+	struct symbol *sym, *pfunc;
+	int symbols_nr, i;
+	char *coldstr;
+	Elf_Data *shndx_data = NULL;
+	Elf32_Word shndx;
+
+	symtab = find_section_by_name(elf, ".symtab");
+	if (symtab) {
+		symtab_shndx = find_section_by_name(elf, ".symtab_shndx");
+		if (symtab_shndx)
+			shndx_data = symtab_shndx->data;
+
+		symbols_nr = sec_num_entries(symtab);
+	} else {
+		/*
+		 * A missing symbol table is actually possible if it's an empty
+		 * .o file. This can happen for thunk_64.o. Make sure to at
+		 * least allocate the symbol hash tables so we can do symbol
+		 * lookups without crashing.
+		 */
+		symbols_nr = 0;
+	}
+
+	if (!elf_alloc_hash(symbol, symbols_nr) ||
+	    !elf_alloc_hash(symbol_name, symbols_nr))
+		return -1;
+
+	elf->symbol_data = calloc(symbols_nr, sizeof(*sym));
+	if (!elf->symbol_data) {
+		perror("calloc");
+		return -1;
+	}
+	for (i = 0; i < symbols_nr; i++) {
+		sym = &elf->symbol_data[i];
+
+		sym->idx = i;
+
+		if (!gelf_getsymshndx(symtab->data, shndx_data, i, &sym->sym,
+				      &shndx)) {
+			WARN_ELF("gelf_getsymshndx");
+			goto err;
+		}
+
+		sym->name = elf_strptr(elf->elf, symtab->sh.sh_link,
+				       sym->sym.st_name);
+		if (!sym->name) {
+			WARN_ELF("elf_strptr");
+			goto err;
+		}
+
+		if ((sym->sym.st_shndx > SHN_UNDEF &&
+		     sym->sym.st_shndx < SHN_LORESERVE) ||
+		    (shndx_data && sym->sym.st_shndx == SHN_XINDEX)) {
+			if (sym->sym.st_shndx != SHN_XINDEX)
+				shndx = sym->sym.st_shndx;
+
+			sym->sec = find_section_by_index(elf, shndx);
+			if (!sym->sec) {
+				WARN("couldn't find section for symbol %s",
+				     sym->name);
+				goto err;
+			}
+			if (GELF_ST_TYPE(sym->sym.st_info) == STT_SECTION) {
+				sym->name = sym->sec->name;
+				sym->sec->sym = sym;
+			}
+		} else
+			sym->sec = find_section_by_index(elf, 0);
+
+		elf_add_symbol(elf, sym);
+	}
+
+	if (opts.stats) {
+		printf("nr_symbols: %lu\n", (unsigned long)symbols_nr);
+		printf("symbol_bits: %d\n", elf->symbol_bits);
+	}
+
+	/* Create parent/child links for any cold subfunctions */
+	list_for_each_entry(sec, &elf->sections, list) {
+		sec_for_each_sym(sec, sym) {
+			char pname[MAX_NAME_LEN + 1];
+			size_t pnamelen;
+			if (sym->type != STT_FUNC)
+				continue;
+
+			if (sym->pfunc == NULL)
+				sym->pfunc = sym;
+
+			if (sym->cfunc == NULL)
+				sym->cfunc = sym;
+
+			coldstr = strstr(sym->name, ".cold");
+			if (!coldstr)
+				continue;
+
+			pnamelen = coldstr - sym->name;
+			if (pnamelen > MAX_NAME_LEN) {
+				WARN("%s(): parent function name exceeds maximum length of %d characters",
+				     sym->name, MAX_NAME_LEN);
+				return -1;
+			}
+
+			strncpy(pname, sym->name, pnamelen);
+			pname[pnamelen] = '\0';
+			pfunc = find_symbol_by_name(elf, pname);
+
+			if (!pfunc) {
+				WARN("%s(): can't find parent function",
+				     sym->name);
+				return -1;
+			}
+
+			sym->pfunc = pfunc;
+			pfunc->cfunc = sym;
+
+			/*
+			 * Unfortunately, -fnoreorder-functions puts the child
+			 * inside the parent.  Remove the overlap so we can
+			 * have sane assumptions.
+			 *
+			 * Note that pfunc->len now no longer matches
+			 * pfunc->sym.st_size.
+			 */
+			if (sym->sec == pfunc->sec &&
+			    sym->offset >= pfunc->offset &&
+			    sym->offset + sym->len == pfunc->offset + pfunc->len) {
+				pfunc->len -= sym->len;
+			}
+		}
+	}
+
+	return 0;
+
+err:
+	free(sym);
+	return -1;
+}
+
+/*
+ * @sym's idx has changed.  Update the relocs which reference it.
+ */
+static int elf_update_sym_relocs(struct elf *elf, struct symbol *sym)
+{
+	struct reloc *reloc;
+
+	for (reloc = sym->relocs; reloc; reloc = reloc->sym_next_reloc)
+		set_reloc_sym(elf, reloc, reloc->sym->idx);
+
+	return 0;
+}
+
+/*
+ * The libelf API is terrible; gelf_update_sym*() takes a data block relative
+ * index value, *NOT* the symbol index. As such, iterate the data blocks and
+ * adjust index until it fits.
+ *
+ * If no data block is found, allow adding a new data block provided the index
+ * is only one past the end.
+ */
+static int elf_update_symbol(struct elf *elf, struct section *symtab,
+			     struct section *symtab_shndx, struct symbol *sym)
+{
+	Elf32_Word shndx = sym->sec ? sym->sec->idx : SHN_UNDEF;
+	Elf_Data *symtab_data = NULL, *shndx_data = NULL;
+	Elf64_Xword entsize = symtab->sh.sh_entsize;
+	int max_idx, idx = sym->idx;
+	Elf_Scn *s, *t = NULL;
+	bool is_special_shndx = sym->sym.st_shndx >= SHN_LORESERVE &&
+				sym->sym.st_shndx != SHN_XINDEX;
+
+	if (is_special_shndx)
+		shndx = sym->sym.st_shndx;
+
+	s = elf_getscn(elf->elf, symtab->idx);
+	if (!s) {
+		WARN_ELF("elf_getscn");
+		return -1;
+	}
+
+	if (symtab_shndx) {
+		t = elf_getscn(elf->elf, symtab_shndx->idx);
+		if (!t) {
+			WARN_ELF("elf_getscn");
+			return -1;
+		}
+	}
+
+	for (;;) {
+		/* get next data descriptor for the relevant sections */
+		symtab_data = elf_getdata(s, symtab_data);
+		if (t)
+			shndx_data = elf_getdata(t, shndx_data);
+
+		/* end-of-list */
+		if (!symtab_data) {
+			/*
+			 * Over-allocate to avoid O(n^2) symbol creation
+			 * behaviour.  The down side is that libelf doesn't
+			 * like this; see elf_truncate_section() for the fixup.
+			 */
+			int num = max(1U, sym->idx/3);
+			void *buf;
+
+			if (idx) {
+				/* we don't do holes in symbol tables */
+				WARN("index out of range");
+				return -1;
+			}
+
+			/* if @idx == 0, it's the next contiguous entry, create it */
+			symtab_data = elf_newdata(s);
+			if (t)
+				shndx_data = elf_newdata(t);
+
+			buf = calloc(num, entsize);
+			if (!buf) {
+				WARN("malloc");
+				return -1;
+			}
+
+			symtab_data->d_buf = buf;
+			symtab_data->d_size = num * entsize;
+			symtab_data->d_align = 1;
+			symtab_data->d_type = ELF_T_SYM;
+
+			mark_sec_changed(elf, symtab, true);
+			symtab->truncate = true;
+
+			if (t) {
+				buf = calloc(num, sizeof(Elf32_Word));
+				if (!buf) {
+					WARN("malloc");
+					return -1;
+				}
+
+				shndx_data->d_buf = buf;
+				shndx_data->d_size = num * sizeof(Elf32_Word);
+				shndx_data->d_align = sizeof(Elf32_Word);
+				shndx_data->d_type = ELF_T_WORD;
+
+				mark_sec_changed(elf, symtab_shndx, true);
+				symtab_shndx->truncate = true;
+			}
+
+			break;
+		}
+
+		/* empty blocks should not happen */
+		if (!symtab_data->d_size) {
+			WARN("zero size data");
+			return -1;
+		}
+
+		/* is this the right block? */
+		max_idx = symtab_data->d_size / entsize;
+		if (idx < max_idx)
+			break;
+
+		/* adjust index and try again */
+		idx -= max_idx;
+	}
+
+	/* something went side-ways */
+	if (idx < 0) {
+		WARN("negative index");
+		return -1;
+	}
+
+	/* setup extended section index magic and write the symbol */
+	if ((shndx >= SHN_UNDEF && shndx < SHN_LORESERVE) || is_special_shndx) {
+		sym->sym.st_shndx = shndx;
+		if (!shndx_data)
+			shndx = 0;
+	} else {
+		sym->sym.st_shndx = SHN_XINDEX;
+		if (!shndx_data) {
+			WARN("no .symtab_shndx");
+			return -1;
+		}
+	}
+
+	if (!gelf_update_symshndx(symtab_data, shndx_data, idx, &sym->sym, shndx)) {
+		WARN_ELF("gelf_update_symshndx");
+		return -1;
+	}
+
+	return 0;
+}
+
+static struct symbol *
+__elf_create_symbol(struct elf *elf, struct symbol *sym)
+{
+	struct section *symtab, *symtab_shndx;
+	Elf32_Word first_non_local, new_idx;
+	struct symbol *old;
+
+	symtab = find_section_by_name(elf, ".symtab");
+	if (symtab) {
+		symtab_shndx = find_section_by_name(elf, ".symtab_shndx");
+	} else {
+		WARN("no .symtab");
+		return NULL;
+	}
+
+	new_idx = sec_num_entries(symtab);
+
+	if (GELF_ST_BIND(sym->sym.st_info) != STB_LOCAL)
+		goto non_local;
+
+	/*
+	 * Move the first global symbol, as per sh_info, into a new, higher
+	 * symbol index. This fees up a spot for a new local symbol.
+	 */
+	first_non_local = symtab->sh.sh_info;
+	old = find_symbol_by_index(elf, first_non_local);
+	if (old) {
+
+		elf_hash_del(symbol, &old->hash, old->idx);
+		elf_hash_add(symbol, &old->hash, new_idx);
+		old->idx = new_idx;
+
+		if (elf_update_symbol(elf, symtab, symtab_shndx, old)) {
+			WARN("elf_update_symbol move");
+			return NULL;
+		}
+
+		if (elf_update_sym_relocs(elf, old))
+			return NULL;
+
+		new_idx = first_non_local;
+	}
+
+	/*
+	 * Either way, we will add a LOCAL symbol.
+	 */
+	symtab->sh.sh_info += 1;
+
+non_local:
+	sym->idx = new_idx;
+	if (elf_update_symbol(elf, symtab, symtab_shndx, sym)) {
+		WARN("elf_update_symbol");
+		return NULL;
+	}
+
+	symtab->sh.sh_size += symtab->sh.sh_entsize;
+	mark_sec_changed(elf, symtab, true);
+
+	if (symtab_shndx) {
+		symtab_shndx->sh.sh_size += sizeof(Elf32_Word);
+		mark_sec_changed(elf, symtab_shndx, true);
+	}
+
+	return sym;
+}
+
+static struct symbol *
+elf_create_section_symbol(struct elf *elf, struct section *sec)
+{
+	struct symbol *sym = calloc(1, sizeof(*sym));
+
+	if (!sym) {
+		perror("malloc");
+		return NULL;
+	}
+
+	sym->name = sec->name;
+	sym->sec = sec;
+
+	// st_name 0
+	sym->sym.st_info = GELF_ST_INFO(STB_LOCAL, STT_SECTION);
+	// st_other 0
+	// st_value 0
+	// st_size 0
+
+	sym = __elf_create_symbol(elf, sym);
+	if (sym)
+		elf_add_symbol(elf, sym);
+
+	return sym;
+}
+
+static int elf_add_string(struct elf *elf, struct section *strtab, char *str);
+
+struct symbol *
+elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, long size)
+{
+	struct symbol *sym = calloc(1, sizeof(*sym));
+	size_t namelen = strlen(orig->name) + sizeof("__pfx_");
+	char *name = malloc(namelen);
+
+	if (!sym || !name) {
+		perror("malloc");
+		return NULL;
+	}
+
+	snprintf(name, namelen, "__pfx_%s", orig->name);
+
+	sym->name = name;
+	sym->sec = orig->sec;
+
+	sym->sym.st_name = elf_add_string(elf, NULL, name);
+	sym->sym.st_info = orig->sym.st_info;
+	sym->sym.st_value = orig->sym.st_value - size;
+	sym->sym.st_size = size;
+
+	sym = __elf_create_symbol(elf, sym);
+	if (sym)
+		elf_add_symbol(elf, sym);
+
+	return sym;
+}
+
+static struct reloc *elf_init_reloc(struct elf *elf, struct section *rsec,
+				    unsigned int reloc_idx,
+				    unsigned long offset, struct symbol *sym,
+				    s64 addend, unsigned int type)
+{
+	struct reloc *reloc, empty = { 0 };
+
+	if (reloc_idx >= sec_num_entries(rsec)) {
+		WARN("%s: bad reloc_idx %u for %s with %d relocs",
+		     __func__, reloc_idx, rsec->name, sec_num_entries(rsec));
+		return NULL;
+	}
+
+	reloc = &rsec->relocs[reloc_idx];
+
+	if (memcmp(reloc, &empty, sizeof(empty))) {
+		WARN("%s: %s: reloc %d already initialized!",
+		     __func__, rsec->name, reloc_idx);
+		return NULL;
+	}
+
+	reloc->sec = rsec;
+	reloc->sym = sym;
+
+	set_reloc_offset(elf, reloc, offset);
+	set_reloc_sym(elf, reloc, sym->idx);
+	set_reloc_type(elf, reloc, type);
+	set_reloc_addend(elf, reloc, addend);
+
+	elf_hash_add(reloc, &reloc->hash, reloc_hash(reloc));
+	reloc->sym_next_reloc = sym->relocs;
+	sym->relocs = reloc;
+
+	return reloc;
+}
+
+struct reloc *elf_init_reloc_text_sym(struct elf *elf, struct section *sec,
+				      unsigned long offset,
+				      unsigned int reloc_idx,
+				      struct section *insn_sec,
+				      unsigned long insn_off)
+{
+	struct symbol *sym = insn_sec->sym;
+	int addend = insn_off;
+
+	if (!(insn_sec->sh.sh_flags & SHF_EXECINSTR)) {
+		WARN("bad call to %s() for data symbol %s",
+		     __func__, sym->name);
+		return NULL;
+	}
+
+	if (!sym) {
+		/*
+		 * Due to how weak functions work, we must use section based
+		 * relocations. Symbol based relocations would result in the
+		 * weak and non-weak function annotations being overlaid on the
+		 * non-weak function after linking.
+		 */
+		sym = elf_create_section_symbol(elf, insn_sec);
+		if (!sym)
+			return NULL;
+
+		insn_sec->sym = sym;
+	}
+
+	return elf_init_reloc(elf, sec->rsec, reloc_idx, offset, sym, addend,
+			      elf_text_rela_type(elf));
+}
+
+struct reloc *elf_init_reloc_data_sym(struct elf *elf, struct section *sec,
+				      unsigned long offset,
+				      unsigned int reloc_idx,
+				      struct symbol *sym,
+				      s64 addend)
+{
+	if (sym->sec && (sec->sh.sh_flags & SHF_EXECINSTR)) {
+		WARN("bad call to %s() for text symbol %s",
+		     __func__, sym->name);
+		return NULL;
+	}
+
+	return elf_init_reloc(elf, sec->rsec, reloc_idx, offset, sym, addend,
+			      elf_data_rela_type(elf));
+}
+
+static int read_relocs(struct elf *elf)
+{
+	unsigned long nr_reloc, max_reloc = 0;
+	struct section *rsec;
+	struct reloc *reloc;
+	unsigned int symndx;
+	struct symbol *sym;
+	int i;
+
+	if (!elf_alloc_hash(reloc, elf->num_relocs))
+		return -1;
+
+	list_for_each_entry(rsec, &elf->sections, list) {
+		if (!is_reloc_sec(rsec))
+			continue;
+
+		rsec->base = find_section_by_index(elf, rsec->sh.sh_info);
+		if (!rsec->base) {
+			WARN("can't find base section for reloc section %s",
+			     rsec->name);
+			return -1;
+		}
+
+		rsec->base->rsec = rsec;
+
+		nr_reloc = 0;
+		rsec->relocs = calloc(sec_num_entries(rsec), sizeof(*reloc));
+		if (!rsec->relocs) {
+			perror("calloc");
+			return -1;
+		}
+		for (i = 0; i < sec_num_entries(rsec); i++) {
+			reloc = &rsec->relocs[i];
+
+			reloc->sec = rsec;
+			symndx = reloc_sym(reloc);
+			reloc->sym = sym = find_symbol_by_index(elf, symndx);
+			if (!reloc->sym) {
+				WARN("can't find reloc entry symbol %d for %s",
+				     symndx, rsec->name);
+				return -1;
+			}
+
+			elf_hash_add(reloc, &reloc->hash, reloc_hash(reloc));
+			reloc->sym_next_reloc = sym->relocs;
+			sym->relocs = reloc;
+
+			nr_reloc++;
+		}
+		max_reloc = max(max_reloc, nr_reloc);
+	}
+
+	if (opts.stats) {
+		printf("max_reloc: %lu\n", max_reloc);
+		printf("num_relocs: %lu\n", elf->num_relocs);
+		printf("reloc_bits: %d\n", elf->reloc_bits);
+	}
+
+	return 0;
+}
+
+struct elf *elf_open_read(const char *name, int flags)
+{
+	struct elf *elf;
+	Elf_Cmd cmd;
+
+	elf_version(EV_CURRENT);
+
+	elf = malloc(sizeof(*elf));
+	if (!elf) {
+		perror("malloc");
+		return NULL;
+	}
+	memset(elf, 0, sizeof(*elf));
+
+	INIT_LIST_HEAD(&elf->sections);
+
+	elf->fd = open(name, flags);
+	if (elf->fd == -1) {
+		fprintf(stderr, "objtool: Can't open '%s': %s\n",
+			name, strerror(errno));
+		goto err;
+	}
+
+	if ((flags & O_ACCMODE) == O_RDONLY)
+		cmd = ELF_C_READ_MMAP;
+	else if ((flags & O_ACCMODE) == O_RDWR)
+		cmd = ELF_C_RDWR;
+	else /* O_WRONLY */
+		cmd = ELF_C_WRITE;
+
+	elf->elf = elf_begin(elf->fd, cmd, NULL);
+	if (!elf->elf) {
+		WARN_ELF("elf_begin");
+		goto err;
+	}
+
+	if (!gelf_getehdr(elf->elf, &elf->ehdr)) {
+		WARN_ELF("gelf_getehdr");
+		goto err;
+	}
+
+	if (read_sections(elf))
+		goto err;
+
+	if (read_symbols(elf))
+		goto err;
+
+	if (read_relocs(elf))
+		goto err;
+
+	return elf;
+
+err:
+	elf_close(elf);
+	return NULL;
+}
+
+static int elf_add_string(struct elf *elf, struct section *strtab, char *str)
+{
+	Elf_Data *data;
+	Elf_Scn *s;
+	int len;
+
+	if (!strtab)
+		strtab = find_section_by_name(elf, ".strtab");
+	if (!strtab) {
+		WARN("can't find .strtab section");
+		return -1;
+	}
+
+	s = elf_getscn(elf->elf, strtab->idx);
+	if (!s) {
+		WARN_ELF("elf_getscn");
+		return -1;
+	}
+
+	data = elf_newdata(s);
+	if (!data) {
+		WARN_ELF("elf_newdata");
+		return -1;
+	}
+
+	data->d_buf = str;
+	data->d_size = strlen(str) + 1;
+	data->d_align = 1;
+
+	len = strtab->sh.sh_size;
+	strtab->sh.sh_size += data->d_size;
+
+	mark_sec_changed(elf, strtab, true);
+
+	return len;
+}
+
+struct section *elf_create_section(struct elf *elf, const char *name,
+				   size_t entsize, unsigned int nr)
+{
+	struct section *sec, *shstrtab;
+	size_t size = entsize * nr;
+	Elf_Scn *s;
+
+	sec = malloc(sizeof(*sec));
+	if (!sec) {
+		perror("malloc");
+		return NULL;
+	}
+	memset(sec, 0, sizeof(*sec));
+
+	INIT_LIST_HEAD(&sec->symbol_list);
+
+	s = elf_newscn(elf->elf);
+	if (!s) {
+		WARN_ELF("elf_newscn");
+		return NULL;
+	}
+
+	sec->name = strdup(name);
+	if (!sec->name) {
+		perror("strdup");
+		return NULL;
+	}
+
+	sec->idx = elf_ndxscn(s);
+
+	sec->data = elf_newdata(s);
+	if (!sec->data) {
+		WARN_ELF("elf_newdata");
+		return NULL;
+	}
+
+	sec->data->d_size = size;
+	sec->data->d_align = 1;
+
+	if (size) {
+		sec->data->d_buf = malloc(size);
+		if (!sec->data->d_buf) {
+			perror("malloc");
+			return NULL;
+		}
+		memset(sec->data->d_buf, 0, size);
+	}
+
+	if (!gelf_getshdr(s, &sec->sh)) {
+		WARN_ELF("gelf_getshdr");
+		return NULL;
+	}
+
+	sec->sh.sh_size = size;
+	sec->sh.sh_entsize = entsize;
+	sec->sh.sh_type = SHT_PROGBITS;
+	sec->sh.sh_addralign = 1;
+	sec->sh.sh_flags = SHF_ALLOC;
+
+	/* Add section name to .shstrtab (or .strtab for Clang) */
+	shstrtab = find_section_by_name(elf, ".shstrtab");
+	if (!shstrtab)
+		shstrtab = find_section_by_name(elf, ".strtab");
+	if (!shstrtab) {
+		WARN("can't find .shstrtab or .strtab section");
+		return NULL;
+	}
+	sec->sh.sh_name = elf_add_string(elf, shstrtab, sec->name);
+	if (sec->sh.sh_name == -1)
+		return NULL;
+
+	list_add_tail(&sec->list, &elf->sections);
+	elf_hash_add(section, &sec->hash, sec->idx);
+	elf_hash_add(section_name, &sec->name_hash, str_hash(sec->name));
+
+	mark_sec_changed(elf, sec, true);
+
+	return sec;
+}
+
+static struct section *elf_create_rela_section(struct elf *elf,
+					       struct section *sec,
+					       unsigned int reloc_nr)
+{
+	struct section *rsec;
+	char *rsec_name;
+
+	rsec_name = malloc(strlen(sec->name) + strlen(".rela") + 1);
+	if (!rsec_name) {
+		perror("malloc");
+		return NULL;
+	}
+	strcpy(rsec_name, ".rela");
+	strcat(rsec_name, sec->name);
+
+	rsec = elf_create_section(elf, rsec_name, elf_rela_size(elf), reloc_nr);
+	free(rsec_name);
+	if (!rsec)
+		return NULL;
+
+	rsec->data->d_type = ELF_T_RELA;
+	rsec->sh.sh_type = SHT_RELA;
+	rsec->sh.sh_addralign = elf_addr_size(elf);
+	rsec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx;
+	rsec->sh.sh_info = sec->idx;
+	rsec->sh.sh_flags = SHF_INFO_LINK;
+
+	rsec->relocs = calloc(sec_num_entries(rsec), sizeof(struct reloc));
+	if (!rsec->relocs) {
+		perror("calloc");
+		return NULL;
+	}
+
+	sec->rsec = rsec;
+	rsec->base = sec;
+
+	return rsec;
+}
+
+struct section *elf_create_section_pair(struct elf *elf, const char *name,
+					size_t entsize, unsigned int nr,
+					unsigned int reloc_nr)
+{
+	struct section *sec;
+
+	sec = elf_create_section(elf, name, entsize, nr);
+	if (!sec)
+		return NULL;
+
+	if (!elf_create_rela_section(elf, sec, reloc_nr))
+		return NULL;
+
+	return sec;
+}
+
+int elf_write_insn(struct elf *elf, struct section *sec,
+		   unsigned long offset, unsigned int len,
+		   const char *insn)
+{
+	Elf_Data *data = sec->data;
+
+	if (data->d_type != ELF_T_BYTE || data->d_off) {
+		WARN("write to unexpected data for section: %s", sec->name);
+		return -1;
+	}
+
+	memcpy(data->d_buf + offset, insn, len);
+
+	mark_sec_changed(elf, sec, true);
+
+	return 0;
+}
+
+/*
+ * When Elf_Scn::sh_size is smaller than the combined Elf_Data::d_size
+ * do you:
+ *
+ *   A) adhere to the section header and truncate the data, or
+ *   B) ignore the section header and write out all the data you've got?
+ *
+ * Yes, libelf sucks and we need to manually truncate if we over-allocate data.
+ */
+static int elf_truncate_section(struct elf *elf, struct section *sec)
+{
+	u64 size = sec->sh.sh_size;
+	bool truncated = false;
+	Elf_Data *data = NULL;
+	Elf_Scn *s;
+
+	s = elf_getscn(elf->elf, sec->idx);
+	if (!s) {
+		WARN_ELF("elf_getscn");
+		return -1;
+	}
+
+	for (;;) {
+		/* get next data descriptor for the relevant section */
+		data = elf_getdata(s, data);
+
+		if (!data) {
+			if (size) {
+				WARN("end of section data but non-zero size left\n");
+				return -1;
+			}
+			return 0;
+		}
+
+		if (truncated) {
+			/* when we remove symbols */
+			WARN("truncated; but more data\n");
+			return -1;
+		}
+
+		if (!data->d_size) {
+			WARN("zero size data");
+			return -1;
+		}
+
+		if (data->d_size > size) {
+			truncated = true;
+			data->d_size = size;
+		}
+
+		size -= data->d_size;
+	}
+}
+
+int elf_write(struct elf *elf)
+{
+	struct section *sec;
+	Elf_Scn *s;
+
+	if (opts.dryrun)
+		return 0;
+
+	/* Update changed relocation sections and section headers: */
+	list_for_each_entry(sec, &elf->sections, list) {
+		if (sec->truncate)
+			elf_truncate_section(elf, sec);
+
+		if (sec_changed(sec)) {
+			s = elf_getscn(elf->elf, sec->idx);
+			if (!s) {
+				WARN_ELF("elf_getscn");
+				return -1;
+			}
+
+			/* Note this also flags the section dirty */
+			if (!gelf_update_shdr(s, &sec->sh)) {
+				WARN_ELF("gelf_update_shdr");
+				return -1;
+			}
+
+			mark_sec_changed(elf, sec, false);
+		}
+	}
+
+	/* Make sure the new section header entries get updated properly. */
+	elf_flagelf(elf->elf, ELF_C_SET, ELF_F_DIRTY);
+
+	/* Write all changes to the file. */
+	if (elf_update(elf->elf, ELF_C_WRITE) < 0) {
+		WARN_ELF("elf_update");
+		return -1;
+	}
+
+	elf->changed = false;
+
+	return 0;
+}
+
+void elf_close(struct elf *elf)
+{
+	if (elf->elf)
+		elf_end(elf->elf);
+
+	if (elf->fd > 0)
+		close(elf->fd);
+
+	/*
+	 * NOTE: All remaining allocations are leaked on purpose.  Objtool is
+	 * about to exit anyway.
+	 */
+}
diff --git a/tools/objtool/include/objtool/arch.h b/tools/objtool/include/objtool/arch.h
new file mode 100644
index 0000000000..0b303eba66
--- /dev/null
+++ b/tools/objtool/include/objtool/arch.h
@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#ifndef _ARCH_H
+#define _ARCH_H
+
+#include <stdbool.h>
+#include <linux/list.h>
+#include <objtool/objtool.h>
+#include <objtool/cfi.h>
+
+enum insn_type {
+	INSN_JUMP_CONDITIONAL,
+	INSN_JUMP_UNCONDITIONAL,
+	INSN_JUMP_DYNAMIC,
+	INSN_JUMP_DYNAMIC_CONDITIONAL,
+	INSN_CALL,
+	INSN_CALL_DYNAMIC,
+	INSN_RETURN,
+	INSN_CONTEXT_SWITCH,
+	INSN_BUG,
+	INSN_NOP,
+	INSN_STAC,
+	INSN_CLAC,
+	INSN_STD,
+	INSN_CLD,
+	INSN_TRAP,
+	INSN_ENDBR,
+	INSN_OTHER,
+};
+
+enum op_dest_type {
+	OP_DEST_REG,
+	OP_DEST_REG_INDIRECT,
+	OP_DEST_MEM,
+	OP_DEST_PUSH,
+	OP_DEST_PUSHF,
+};
+
+struct op_dest {
+	enum op_dest_type type;
+	unsigned char reg;
+	int offset;
+};
+
+enum op_src_type {
+	OP_SRC_REG,
+	OP_SRC_REG_INDIRECT,
+	OP_SRC_CONST,
+	OP_SRC_POP,
+	OP_SRC_POPF,
+	OP_SRC_ADD,
+	OP_SRC_AND,
+};
+
+struct op_src {
+	enum op_src_type type;
+	unsigned char reg;
+	int offset;
+};
+
+struct stack_op {
+	struct stack_op *next;
+	struct op_dest dest;
+	struct op_src src;
+};
+
+struct instruction;
+
+int arch_ftrace_match(char *name);
+
+void arch_initial_func_cfi_state(struct cfi_init_state *state);
+
+int arch_decode_instruction(struct objtool_file *file, const struct section *sec,
+			    unsigned long offset, unsigned int maxlen,
+			    struct instruction *insn);
+
+bool arch_callee_saved_reg(unsigned char reg);
+
+unsigned long arch_jump_destination(struct instruction *insn);
+
+unsigned long arch_dest_reloc_offset(int addend);
+
+const char *arch_nop_insn(int len);
+const char *arch_ret_insn(int len);
+
+int arch_decode_hint_reg(u8 sp_reg, int *base);
+
+bool arch_is_retpoline(struct symbol *sym);
+bool arch_is_rethunk(struct symbol *sym);
+bool arch_is_embedded_insn(struct symbol *sym);
+
+int arch_rewrite_retpolines(struct objtool_file *file);
+
+bool arch_pc_relative_reloc(struct reloc *reloc);
+
+#endif /* _ARCH_H */
diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h
new file mode 100644
index 0000000000..fcca6662c8
--- /dev/null
+++ b/tools/objtool/include/objtool/builtin.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+#ifndef _BUILTIN_H
+#define _BUILTIN_H
+
+#include <subcmd/parse-options.h>
+
+struct opts {
+	/* actions: */
+	bool dump_orc;
+	bool hack_jump_label;
+	bool hack_noinstr;
+	bool hack_skylake;
+	bool ibt;
+	bool mcount;
+	bool noinstr;
+	bool orc;
+	bool retpoline;
+	bool rethunk;
+	bool unret;
+	bool sls;
+	bool stackval;
+	bool static_call;
+	bool uaccess;
+	int prefix;
+	bool cfi;
+
+	/* options: */
+	bool backtrace;
+	bool backup;
+	bool dryrun;
+	bool link;
+	bool mnop;
+	bool module;
+	bool no_unreachable;
+	bool sec_address;
+	bool stats;
+	bool verbose;
+};
+
+extern struct opts opts;
+
+extern int cmd_parse_options(int argc, const char **argv, const char * const usage[]);
+
+extern int objtool_run(int argc, const char **argv);
+
+#endif /* _BUILTIN_H */
diff --git a/tools/objtool/include/objtool/cfi.h b/tools/objtool/include/objtool/cfi.h
new file mode 100644
index 0000000000..c8a6bec4f6
--- /dev/null
+++ b/tools/objtool/include/objtool/cfi.h
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2015-2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#ifndef _OBJTOOL_CFI_H
+#define _OBJTOOL_CFI_H
+
+#include <arch/cfi_regs.h>
+#include <linux/list.h>
+
+#define CFI_UNDEFINED		-1
+#define CFI_CFA			-2
+#define CFI_SP_INDIRECT		-3
+#define CFI_BP_INDIRECT		-4
+
+struct cfi_reg {
+	int base;
+	int offset;
+};
+
+struct cfi_init_state {
+	struct cfi_reg regs[CFI_NUM_REGS];
+	struct cfi_reg cfa;
+};
+
+struct cfi_state {
+	struct hlist_node hash; /* must be first, cficmp() */
+	struct cfi_reg regs[CFI_NUM_REGS];
+	struct cfi_reg vals[CFI_NUM_REGS];
+	struct cfi_reg cfa;
+	int stack_size;
+	int drap_reg, drap_offset;
+	unsigned char type;
+	bool bp_scratch;
+	bool drap;
+	bool signal;
+	bool end;
+	bool force_undefined;
+};
+
+#endif /* _OBJTOOL_CFI_H */
diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h
new file mode 100644
index 0000000000..daa46f1f09
--- /dev/null
+++ b/tools/objtool/include/objtool/check.h
@@ -0,0 +1,124 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#ifndef _CHECK_H
+#define _CHECK_H
+
+#include <stdbool.h>
+#include <objtool/cfi.h>
+#include <objtool/arch.h>
+
+struct insn_state {
+	struct cfi_state cfi;
+	unsigned int uaccess_stack;
+	bool uaccess;
+	bool df;
+	bool noinstr;
+	s8 instr;
+};
+
+struct alt_group {
+	/*
+	 * Pointer from a replacement group to the original group.  NULL if it
+	 * *is* the original group.
+	 */
+	struct alt_group *orig_group;
+
+	/* First and last instructions in the group */
+	struct instruction *first_insn, *last_insn, *nop;
+
+	/*
+	 * Byte-offset-addressed len-sized array of pointers to CFI structs.
+	 * This is shared with the other alt_groups in the same alternative.
+	 */
+	struct cfi_state **cfi;
+};
+
+#define INSN_CHUNK_BITS		8
+#define INSN_CHUNK_SIZE		(1 << INSN_CHUNK_BITS)
+#define INSN_CHUNK_MAX		(INSN_CHUNK_SIZE - 1)
+
+struct instruction {
+	struct hlist_node hash;
+	struct list_head call_node;
+	struct section *sec;
+	unsigned long offset;
+	unsigned long immediate;
+
+	u8 len;
+	u8 prev_len;
+	u8 type;
+	s8 instr;
+
+	u32 idx			: INSN_CHUNK_BITS,
+	    dead_end		: 1,
+	    ignore		: 1,
+	    ignore_alts		: 1,
+	    hint		: 1,
+	    save		: 1,
+	    restore		: 1,
+	    retpoline_safe	: 1,
+	    noendbr		: 1,
+	    unret		: 1,
+	    visited		: 4,
+	    no_reloc		: 1;
+		/* 10 bit hole */
+
+	struct alt_group *alt_group;
+	struct instruction *jump_dest;
+	struct instruction *first_jump_src;
+	union {
+		struct symbol *_call_dest;
+		struct reloc *_jump_table;
+	};
+	struct alternative *alts;
+	struct symbol *sym;
+	struct stack_op *stack_ops;
+	struct cfi_state *cfi;
+};
+
+static inline struct symbol *insn_func(struct instruction *insn)
+{
+	struct symbol *sym = insn->sym;
+
+	if (sym && sym->type != STT_FUNC)
+		sym = NULL;
+
+	return sym;
+}
+
+#define VISITED_BRANCH		0x01
+#define VISITED_BRANCH_UACCESS	0x02
+#define VISITED_BRANCH_MASK	0x03
+#define VISITED_UNRET		0x04
+
+static inline bool is_static_jump(struct instruction *insn)
+{
+	return insn->type == INSN_JUMP_CONDITIONAL ||
+	       insn->type == INSN_JUMP_UNCONDITIONAL;
+}
+
+static inline bool is_dynamic_jump(struct instruction *insn)
+{
+	return insn->type == INSN_JUMP_DYNAMIC ||
+	       insn->type == INSN_JUMP_DYNAMIC_CONDITIONAL;
+}
+
+static inline bool is_jump(struct instruction *insn)
+{
+	return is_static_jump(insn) || is_dynamic_jump(insn);
+}
+
+struct instruction *find_insn(struct objtool_file *file,
+			      struct section *sec, unsigned long offset);
+
+struct instruction *next_insn_same_sec(struct objtool_file *file, struct instruction *insn);
+
+#define sec_for_each_insn(file, _sec, insn)				\
+	for (insn = find_insn(file, _sec, 0);				\
+	     insn && insn->sec == _sec;					\
+	     insn = next_insn_same_sec(file, insn))
+
+#endif /* _CHECK_H */
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
new file mode 100644
index 0000000000..9f71e988ec
--- /dev/null
+++ b/tools/objtool/include/objtool/elf.h
@@ -0,0 +1,350 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#ifndef _OBJTOOL_ELF_H
+#define _OBJTOOL_ELF_H
+
+#include <stdio.h>
+#include <gelf.h>
+#include <linux/list.h>
+#include <linux/hashtable.h>
+#include <linux/rbtree.h>
+#include <linux/jhash.h>
+#include <arch/elf.h>
+
+#ifdef LIBELF_USE_DEPRECATED
+# define elf_getshdrnum    elf_getshnum
+# define elf_getshdrstrndx elf_getshstrndx
+#endif
+
+/*
+ * Fallback for systems without this "read, mmaping if possible" cmd.
+ */
+#ifndef ELF_C_READ_MMAP
+#define ELF_C_READ_MMAP ELF_C_READ
+#endif
+
+struct elf_hash_node {
+	struct elf_hash_node *next;
+};
+
+struct section {
+	struct list_head list;
+	struct elf_hash_node hash;
+	struct elf_hash_node name_hash;
+	GElf_Shdr sh;
+	struct rb_root_cached symbol_tree;
+	struct list_head symbol_list;
+	struct section *base, *rsec;
+	struct symbol *sym;
+	Elf_Data *data;
+	char *name;
+	int idx;
+	bool _changed, text, rodata, noinstr, init, truncate;
+	struct reloc *relocs;
+};
+
+struct symbol {
+	struct list_head list;
+	struct rb_node node;
+	struct elf_hash_node hash;
+	struct elf_hash_node name_hash;
+	GElf_Sym sym;
+	struct section *sec;
+	char *name;
+	unsigned int idx, len;
+	unsigned long offset;
+	unsigned long __subtree_last;
+	struct symbol *pfunc, *cfunc, *alias;
+	unsigned char bind, type;
+	u8 uaccess_safe      : 1;
+	u8 static_call_tramp : 1;
+	u8 retpoline_thunk   : 1;
+	u8 return_thunk      : 1;
+	u8 fentry            : 1;
+	u8 profiling_func    : 1;
+	u8 warned	     : 1;
+	u8 embedded_insn     : 1;
+	struct list_head pv_target;
+	struct reloc *relocs;
+};
+
+struct reloc {
+	struct elf_hash_node hash;
+	struct section *sec;
+	struct symbol *sym;
+	struct reloc *sym_next_reloc;
+};
+
+struct elf {
+	Elf *elf;
+	GElf_Ehdr ehdr;
+	int fd;
+	bool changed;
+	char *name;
+	unsigned int num_files;
+	struct list_head sections;
+	unsigned long num_relocs;
+
+	int symbol_bits;
+	int symbol_name_bits;
+	int section_bits;
+	int section_name_bits;
+	int reloc_bits;
+
+	struct elf_hash_node **symbol_hash;
+	struct elf_hash_node **symbol_name_hash;
+	struct elf_hash_node **section_hash;
+	struct elf_hash_node **section_name_hash;
+	struct elf_hash_node **reloc_hash;
+
+	struct section *section_data;
+	struct symbol *symbol_data;
+};
+
+struct elf *elf_open_read(const char *name, int flags);
+
+struct section *elf_create_section(struct elf *elf, const char *name,
+				   size_t entsize, unsigned int nr);
+struct section *elf_create_section_pair(struct elf *elf, const char *name,
+					size_t entsize, unsigned int nr,
+					unsigned int reloc_nr);
+
+struct symbol *elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, long size);
+
+struct reloc *elf_init_reloc_text_sym(struct elf *elf, struct section *sec,
+				      unsigned long offset,
+				      unsigned int reloc_idx,
+				      struct section *insn_sec,
+				      unsigned long insn_off);
+
+struct reloc *elf_init_reloc_data_sym(struct elf *elf, struct section *sec,
+				      unsigned long offset,
+				      unsigned int reloc_idx,
+				      struct symbol *sym,
+				      s64 addend);
+
+int elf_write_insn(struct elf *elf, struct section *sec,
+		   unsigned long offset, unsigned int len,
+		   const char *insn);
+int elf_write(struct elf *elf);
+void elf_close(struct elf *elf);
+
+struct section *find_section_by_name(const struct elf *elf, const char *name);
+struct symbol *find_func_by_offset(struct section *sec, unsigned long offset);
+struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
+struct symbol *find_symbol_by_name(const struct elf *elf, const char *name);
+struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset);
+int find_symbol_hole_containing(const struct section *sec, unsigned long offset);
+struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset);
+struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
+				     unsigned long offset, unsigned int len);
+struct symbol *find_func_containing(struct section *sec, unsigned long offset);
+
+/*
+ * Try to see if it's a whole archive (vmlinux.o or module).
+ *
+ * Note this will miss the case where a module only has one source file.
+ */
+static inline bool has_multiple_files(struct elf *elf)
+{
+	return elf->num_files > 1;
+}
+
+static inline size_t elf_addr_size(struct elf *elf)
+{
+	return elf->ehdr.e_ident[EI_CLASS] == ELFCLASS32 ? 4 : 8;
+}
+
+static inline size_t elf_rela_size(struct elf *elf)
+{
+	return elf_addr_size(elf) == 4 ? sizeof(Elf32_Rela) : sizeof(Elf64_Rela);
+}
+
+static inline unsigned int elf_data_rela_type(struct elf *elf)
+{
+	return elf_addr_size(elf) == 4 ? R_DATA32 : R_DATA64;
+}
+
+static inline unsigned int elf_text_rela_type(struct elf *elf)
+{
+	return elf_addr_size(elf) == 4 ? R_TEXT32 : R_TEXT64;
+}
+
+static inline bool is_reloc_sec(struct section *sec)
+{
+	return sec->sh.sh_type == SHT_RELA || sec->sh.sh_type == SHT_REL;
+}
+
+static inline bool sec_changed(struct section *sec)
+{
+	return sec->_changed;
+}
+
+static inline void mark_sec_changed(struct elf *elf, struct section *sec,
+				    bool changed)
+{
+	sec->_changed = changed;
+	elf->changed |= changed;
+}
+
+static inline unsigned int sec_num_entries(struct section *sec)
+{
+	return sec->sh.sh_size / sec->sh.sh_entsize;
+}
+
+static inline unsigned int reloc_idx(struct reloc *reloc)
+{
+	return reloc - reloc->sec->relocs;
+}
+
+static inline void *reloc_rel(struct reloc *reloc)
+{
+	struct section *rsec = reloc->sec;
+
+	return rsec->data->d_buf + (reloc_idx(reloc) * rsec->sh.sh_entsize);
+}
+
+static inline bool is_32bit_reloc(struct reloc *reloc)
+{
+	/*
+	 * Elf32_Rel:   8 bytes
+	 * Elf32_Rela: 12 bytes
+	 * Elf64_Rel:  16 bytes
+	 * Elf64_Rela: 24 bytes
+	 */
+	return reloc->sec->sh.sh_entsize < 16;
+}
+
+#define __get_reloc_field(reloc, field)					\
+({									\
+	is_32bit_reloc(reloc) ?						\
+		((Elf32_Rela *)reloc_rel(reloc))->field :		\
+		((Elf64_Rela *)reloc_rel(reloc))->field;		\
+})
+
+#define __set_reloc_field(reloc, field, val)				\
+({									\
+	if (is_32bit_reloc(reloc))					\
+		((Elf32_Rela *)reloc_rel(reloc))->field = val;		\
+	else								\
+		((Elf64_Rela *)reloc_rel(reloc))->field = val;		\
+})
+
+static inline u64 reloc_offset(struct reloc *reloc)
+{
+	return __get_reloc_field(reloc, r_offset);
+}
+
+static inline void set_reloc_offset(struct elf *elf, struct reloc *reloc, u64 offset)
+{
+	__set_reloc_field(reloc, r_offset, offset);
+	mark_sec_changed(elf, reloc->sec, true);
+}
+
+static inline s64 reloc_addend(struct reloc *reloc)
+{
+	return __get_reloc_field(reloc, r_addend);
+}
+
+static inline void set_reloc_addend(struct elf *elf, struct reloc *reloc, s64 addend)
+{
+	__set_reloc_field(reloc, r_addend, addend);
+	mark_sec_changed(elf, reloc->sec, true);
+}
+
+
+static inline unsigned int reloc_sym(struct reloc *reloc)
+{
+	u64 info = __get_reloc_field(reloc, r_info);
+
+	return is_32bit_reloc(reloc) ?
+		ELF32_R_SYM(info) :
+		ELF64_R_SYM(info);
+}
+
+static inline unsigned int reloc_type(struct reloc *reloc)
+{
+	u64 info = __get_reloc_field(reloc, r_info);
+
+	return is_32bit_reloc(reloc) ?
+		ELF32_R_TYPE(info) :
+		ELF64_R_TYPE(info);
+}
+
+static inline void set_reloc_sym(struct elf *elf, struct reloc *reloc, unsigned int sym)
+{
+	u64 info = is_32bit_reloc(reloc) ?
+		ELF32_R_INFO(sym, reloc_type(reloc)) :
+		ELF64_R_INFO(sym, reloc_type(reloc));
+
+	__set_reloc_field(reloc, r_info, info);
+
+	mark_sec_changed(elf, reloc->sec, true);
+}
+static inline void set_reloc_type(struct elf *elf, struct reloc *reloc, unsigned int type)
+{
+	u64 info = is_32bit_reloc(reloc) ?
+		ELF32_R_INFO(reloc_sym(reloc), type) :
+		ELF64_R_INFO(reloc_sym(reloc), type);
+
+	__set_reloc_field(reloc, r_info, info);
+
+	mark_sec_changed(elf, reloc->sec, true);
+}
+
+#define for_each_sec(file, sec)						\
+	list_for_each_entry(sec, &file->elf->sections, list)
+
+#define sec_for_each_sym(sec, sym)					\
+	list_for_each_entry(sym, &sec->symbol_list, list)
+
+#define for_each_sym(file, sym)						\
+	for (struct section *__sec, *__fake = (struct section *)1;	\
+	     __fake; __fake = NULL)					\
+		for_each_sec(file, __sec)				\
+			sec_for_each_sym(__sec, sym)
+
+#define for_each_reloc(rsec, reloc)					\
+	for (int __i = 0, __fake = 1; __fake; __fake = 0)		\
+		for (reloc = rsec->relocs;				\
+		     __i < sec_num_entries(rsec);			\
+		     __i++, reloc++)
+
+#define for_each_reloc_from(rsec, reloc)				\
+	for (int __i = reloc_idx(reloc);				\
+	     __i < sec_num_entries(rsec);				\
+	     __i++, reloc++)
+
+#define OFFSET_STRIDE_BITS	4
+#define OFFSET_STRIDE		(1UL << OFFSET_STRIDE_BITS)
+#define OFFSET_STRIDE_MASK	(~(OFFSET_STRIDE - 1))
+
+#define for_offset_range(_offset, _start, _end)			\
+	for (_offset = ((_start) & OFFSET_STRIDE_MASK);		\
+	     _offset >= ((_start) & OFFSET_STRIDE_MASK) &&	\
+	     _offset <= ((_end) & OFFSET_STRIDE_MASK);		\
+	     _offset += OFFSET_STRIDE)
+
+static inline u32 sec_offset_hash(struct section *sec, unsigned long offset)
+{
+	u32 ol, oh, idx = sec->idx;
+
+	offset &= OFFSET_STRIDE_MASK;
+
+	ol = offset;
+	oh = (offset >> 16) >> 16;
+
+	__jhash_mix(ol, oh, idx);
+
+	return ol;
+}
+
+static inline u32 reloc_hash(struct reloc *reloc)
+{
+	return sec_offset_hash(reloc->sec, reloc_offset(reloc));
+}
+
+#endif /* _OBJTOOL_ELF_H */
diff --git a/tools/objtool/include/objtool/endianness.h b/tools/objtool/include/objtool/endianness.h
new file mode 100644
index 0000000000..4d2aa9b0fe
--- /dev/null
+++ b/tools/objtool/include/objtool/endianness.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _OBJTOOL_ENDIANNESS_H
+#define _OBJTOOL_ENDIANNESS_H
+
+#include <linux/kernel.h>
+#include <endian.h>
+#include <objtool/elf.h>
+
+/*
+ * Does a byte swap if target file endianness doesn't match the host, i.e. cross
+ * compilation for little endian on big endian and vice versa.
+ * To be used for multi-byte values conversion, which are read from / about
+ * to be written to a target native endianness ELF file.
+ */
+static inline bool need_bswap(struct elf *elf)
+{
+	return (__BYTE_ORDER == __LITTLE_ENDIAN) ^
+	       (elf->ehdr.e_ident[EI_DATA] == ELFDATA2LSB);
+}
+
+#define bswap_if_needed(elf, val)					\
+({									\
+	__typeof__(val) __ret;						\
+	bool __need_bswap = need_bswap(elf);				\
+	switch (sizeof(val)) {						\
+	case 8:								\
+		__ret = __need_bswap ? bswap_64(val) : (val); break;	\
+	case 4:								\
+		__ret = __need_bswap ? bswap_32(val) : (val); break;	\
+	case 2:								\
+		__ret = __need_bswap ? bswap_16(val) : (val); break;	\
+	default:							\
+		BUILD_BUG(); break;					\
+	}								\
+	__ret;								\
+})
+
+#endif /* _OBJTOOL_ENDIANNESS_H */
diff --git a/tools/objtool/include/objtool/objtool.h b/tools/objtool/include/objtool/objtool.h
new file mode 100644
index 0000000000..94a33ee7b3
--- /dev/null
+++ b/tools/objtool/include/objtool/objtool.h
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2020 Matt Helsley <mhelsley@vmware.com>
+ */
+
+#ifndef _OBJTOOL_H
+#define _OBJTOOL_H
+
+#include <stdbool.h>
+#include <linux/list.h>
+#include <linux/hashtable.h>
+
+#include <objtool/elf.h>
+
+#define __weak __attribute__((weak))
+
+struct pv_state {
+	bool clean;
+	struct list_head targets;
+};
+
+struct objtool_file {
+	struct elf *elf;
+	DECLARE_HASHTABLE(insn_hash, 20);
+	struct list_head retpoline_call_list;
+	struct list_head return_thunk_list;
+	struct list_head static_call_list;
+	struct list_head mcount_loc_list;
+	struct list_head endbr_list;
+	struct list_head call_list;
+	bool ignore_unreachables, hints, rodata;
+
+	unsigned int nr_endbr;
+	unsigned int nr_endbr_int;
+
+	unsigned long jl_short, jl_long;
+	unsigned long jl_nop_short, jl_nop_long;
+
+	struct pv_state *pv_ops;
+};
+
+struct objtool_file *objtool_open_read(const char *_objname);
+
+void objtool_pv_add(struct objtool_file *file, int idx, struct symbol *func);
+
+int check(struct objtool_file *file);
+int orc_dump(const char *objname);
+int orc_create(struct objtool_file *file);
+
+#endif /* _OBJTOOL_H */
diff --git a/tools/objtool/include/objtool/special.h b/tools/objtool/include/objtool/special.h
new file mode 100644
index 0000000000..86d4af9c5a
--- /dev/null
+++ b/tools/objtool/include/objtool/special.h
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#ifndef _SPECIAL_H
+#define _SPECIAL_H
+
+#include <stdbool.h>
+#include <objtool/check.h>
+#include <objtool/elf.h>
+
+#define C_JUMP_TABLE_SECTION ".rodata..c_jump_table"
+
+struct special_alt {
+	struct list_head list;
+
+	bool group;
+	bool skip_orig;
+	bool skip_alt;
+	bool jump_or_nop;
+	u8 key_addend;
+
+	struct section *orig_sec;
+	unsigned long orig_off;
+
+	struct section *new_sec;
+	unsigned long new_off;
+
+	unsigned int orig_len, new_len; /* group only */
+};
+
+int special_get_alts(struct elf *elf, struct list_head *alts);
+
+void arch_handle_alternative(unsigned short feature, struct special_alt *alt);
+
+bool arch_support_alt_relocation(struct special_alt *special_alt,
+				 struct instruction *insn,
+				 struct reloc *reloc);
+struct reloc *arch_find_switch_table(struct objtool_file *file,
+				    struct instruction *insn);
+#endif /* _SPECIAL_H */
diff --git a/tools/objtool/include/objtool/warn.h b/tools/objtool/include/objtool/warn.h
new file mode 100644
index 0000000000..ac04d3fe4d
--- /dev/null
+++ b/tools/objtool/include/objtool/warn.h
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#ifndef _WARN_H
+#define _WARN_H
+
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <objtool/builtin.h>
+#include <objtool/elf.h>
+
+extern const char *objname;
+
+static inline char *offstr(struct section *sec, unsigned long offset)
+{
+	bool is_text = (sec->sh.sh_flags & SHF_EXECINSTR);
+	struct symbol *sym = NULL;
+	char *str;
+	int len;
+
+	if (is_text)
+		sym = find_func_containing(sec, offset);
+	if (!sym)
+		sym = find_symbol_containing(sec, offset);
+
+	if (sym) {
+		str = malloc(strlen(sym->name) + strlen(sec->name) + 40);
+		len = sprintf(str, "%s+0x%lx", sym->name, offset - sym->offset);
+		if (opts.sec_address)
+			sprintf(str+len, " (%s+0x%lx)", sec->name, offset);
+	} else {
+		str = malloc(strlen(sec->name) + 20);
+		sprintf(str, "%s+0x%lx", sec->name, offset);
+	}
+
+	return str;
+}
+
+#define WARN(format, ...)				\
+	fprintf(stderr,					\
+		"%s: warning: objtool: " format "\n",	\
+		objname, ##__VA_ARGS__)
+
+#define WARN_FUNC(format, sec, offset, ...)		\
+({							\
+	char *_str = offstr(sec, offset);		\
+	WARN("%s: " format, _str, ##__VA_ARGS__);	\
+	free(_str);					\
+})
+
+#define WARN_INSN(insn, format, ...)					\
+({									\
+	struct instruction *_insn = (insn);				\
+	if (!_insn->sym || !_insn->sym->warned)				\
+		WARN_FUNC(format, _insn->sec, _insn->offset,		\
+			  ##__VA_ARGS__);				\
+	if (_insn->sym)							\
+		_insn->sym->warned = 1;					\
+})
+
+#define BT_INSN(insn, format, ...)				\
+({								\
+	if (opts.verbose || opts.backtrace) {			\
+		struct instruction *_insn = (insn);		\
+		char *_str = offstr(_insn->sec, _insn->offset); \
+		WARN("  %s: " format, _str, ##__VA_ARGS__);	\
+		free(_str);					\
+	}							\
+})
+
+#define WARN_ELF(format, ...)				\
+	WARN(format ": %s", ##__VA_ARGS__, elf_errmsg(-1))
+
+#endif /* _WARN_H */
diff --git a/tools/objtool/noreturns.h b/tools/objtool/noreturns.h
new file mode 100644
index 0000000000..80a3e6acf3
--- /dev/null
+++ b/tools/objtool/noreturns.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * This is a (sorted!) list of all known __noreturn functions in the kernel.
+ * It's needed for objtool to properly reverse-engineer the control flow graph.
+ *
+ * Yes, this is unfortunate.  A better solution is in the works.
+ */
+NORETURN(__kunit_abort)
+NORETURN(__module_put_and_kthread_exit)
+NORETURN(__reiserfs_panic)
+NORETURN(__stack_chk_fail)
+NORETURN(__ubsan_handle_builtin_unreachable)
+NORETURN(arch_call_rest_init)
+NORETURN(arch_cpu_idle_dead)
+NORETURN(cpu_bringup_and_idle)
+NORETURN(cpu_startup_entry)
+NORETURN(do_exit)
+NORETURN(do_group_exit)
+NORETURN(do_task_dead)
+NORETURN(ex_handler_msr_mce)
+NORETURN(fortify_panic)
+NORETURN(hlt_play_dead)
+NORETURN(hv_ghcb_terminate)
+NORETURN(kthread_complete_and_exit)
+NORETURN(kthread_exit)
+NORETURN(kunit_try_catch_throw)
+NORETURN(machine_real_restart)
+NORETURN(make_task_dead)
+NORETURN(mpt_halt_firmware)
+NORETURN(nmi_panic_self_stop)
+NORETURN(panic)
+NORETURN(panic_smp_self_stop)
+NORETURN(rest_init)
+NORETURN(rewind_stack_and_make_dead)
+NORETURN(sev_es_terminate)
+NORETURN(snp_abort)
+NORETURN(start_kernel)
+NORETURN(stop_this_cpu)
+NORETURN(usercopy_abort)
+NORETURN(x86_64_start_kernel)
+NORETURN(x86_64_start_reservations)
+NORETURN(xen_cpu_bringup_again)
+NORETURN(xen_start_kernel)
diff --git a/tools/objtool/objtool.c b/tools/objtool/objtool.c
new file mode 100644
index 0000000000..f40febdd6e
--- /dev/null
+++ b/tools/objtool/objtool.c
@@ -0,0 +1,150 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#include <stdio.h>
+#include <stdbool.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <subcmd/exec-cmd.h>
+#include <subcmd/pager.h>
+#include <linux/kernel.h>
+
+#include <objtool/builtin.h>
+#include <objtool/objtool.h>
+#include <objtool/warn.h>
+
+bool help;
+
+const char *objname;
+static struct objtool_file file;
+
+static bool objtool_create_backup(const char *_objname)
+{
+	int len = strlen(_objname);
+	char *buf, *base, *name = malloc(len+6);
+	int s, d, l, t;
+
+	if (!name) {
+		perror("failed backup name malloc");
+		return false;
+	}
+
+	strcpy(name, _objname);
+	strcpy(name + len, ".orig");
+
+	d = open(name, O_CREAT|O_WRONLY|O_TRUNC, 0644);
+	if (d < 0) {
+		perror("failed to create backup file");
+		return false;
+	}
+
+	s = open(_objname, O_RDONLY);
+	if (s < 0) {
+		perror("failed to open orig file");
+		return false;
+	}
+
+	buf = malloc(4096);
+	if (!buf) {
+		perror("failed backup data malloc");
+		return false;
+	}
+
+	while ((l = read(s, buf, 4096)) > 0) {
+		base = buf;
+		do {
+			t = write(d, base, l);
+			if (t < 0) {
+				perror("failed backup write");
+				return false;
+			}
+			base += t;
+			l -= t;
+		} while (l);
+	}
+
+	if (l < 0) {
+		perror("failed backup read");
+		return false;
+	}
+
+	free(name);
+	free(buf);
+	close(d);
+	close(s);
+
+	return true;
+}
+
+struct objtool_file *objtool_open_read(const char *_objname)
+{
+	if (objname) {
+		if (strcmp(objname, _objname)) {
+			WARN("won't handle more than one file at a time");
+			return NULL;
+		}
+		return &file;
+	}
+	objname = _objname;
+
+	file.elf = elf_open_read(objname, O_RDWR);
+	if (!file.elf)
+		return NULL;
+
+	if (opts.backup && !objtool_create_backup(objname)) {
+		WARN("can't create backup file");
+		return NULL;
+	}
+
+	hash_init(file.insn_hash);
+	INIT_LIST_HEAD(&file.retpoline_call_list);
+	INIT_LIST_HEAD(&file.return_thunk_list);
+	INIT_LIST_HEAD(&file.static_call_list);
+	INIT_LIST_HEAD(&file.mcount_loc_list);
+	INIT_LIST_HEAD(&file.endbr_list);
+	INIT_LIST_HEAD(&file.call_list);
+	file.ignore_unreachables = opts.no_unreachable;
+	file.hints = false;
+
+	return &file;
+}
+
+void objtool_pv_add(struct objtool_file *f, int idx, struct symbol *func)
+{
+	if (!opts.noinstr)
+		return;
+
+	if (!f->pv_ops) {
+		WARN("paravirt confusion");
+		return;
+	}
+
+	/*
+	 * These functions will be patched into native code,
+	 * see paravirt_patch().
+	 */
+	if (!strcmp(func->name, "_paravirt_nop") ||
+	    !strcmp(func->name, "_paravirt_ident_64"))
+		return;
+
+	/* already added this function */
+	if (!list_empty(&func->pv_target))
+		return;
+
+	list_add(&func->pv_target, &f->pv_ops[idx].targets);
+	f->pv_ops[idx].clean = false;
+}
+
+int main(int argc, const char **argv)
+{
+	static const char *UNUSED = "OBJTOOL_NOT_IMPLEMENTED";
+
+	/* libsubcmd init */
+	exec_cmd_init("objtool", UNUSED, UNUSED, UNUSED);
+	pager_init(UNUSED);
+
+	return objtool_run(argc, argv);
+}
diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c
new file mode 100644
index 0000000000..0e183bb1c7
--- /dev/null
+++ b/tools/objtool/orc_dump.c
@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#include <unistd.h>
+#include <asm/orc_types.h>
+#include <objtool/objtool.h>
+#include <objtool/warn.h>
+#include <objtool/endianness.h>
+
+static const char *reg_name(unsigned int reg)
+{
+	switch (reg) {
+	case ORC_REG_PREV_SP:
+		return "prevsp";
+	case ORC_REG_DX:
+		return "dx";
+	case ORC_REG_DI:
+		return "di";
+	case ORC_REG_BP:
+		return "bp";
+	case ORC_REG_SP:
+		return "sp";
+	case ORC_REG_R10:
+		return "r10";
+	case ORC_REG_R13:
+		return "r13";
+	case ORC_REG_BP_INDIRECT:
+		return "bp(ind)";
+	case ORC_REG_SP_INDIRECT:
+		return "sp(ind)";
+	default:
+		return "?";
+	}
+}
+
+static const char *orc_type_name(unsigned int type)
+{
+	switch (type) {
+	case ORC_TYPE_UNDEFINED:
+		return "(und)";
+	case ORC_TYPE_END_OF_STACK:
+		return "end";
+	case ORC_TYPE_CALL:
+		return "call";
+	case ORC_TYPE_REGS:
+		return "regs";
+	case ORC_TYPE_REGS_PARTIAL:
+		return "regs (partial)";
+	default:
+		return "?";
+	}
+}
+
+static void print_reg(unsigned int reg, int offset)
+{
+	if (reg == ORC_REG_BP_INDIRECT)
+		printf("(bp%+d)", offset);
+	else if (reg == ORC_REG_SP_INDIRECT)
+		printf("(sp)%+d", offset);
+	else if (reg == ORC_REG_UNDEFINED)
+		printf("(und)");
+	else
+		printf("%s%+d", reg_name(reg), offset);
+}
+
+int orc_dump(const char *_objname)
+{
+	int fd, nr_entries, i, *orc_ip = NULL, orc_size = 0;
+	struct orc_entry *orc = NULL;
+	char *name;
+	size_t nr_sections;
+	Elf64_Addr orc_ip_addr = 0;
+	size_t shstrtab_idx, strtab_idx = 0;
+	Elf *elf;
+	Elf_Scn *scn;
+	GElf_Shdr sh;
+	GElf_Rela rela;
+	GElf_Sym sym;
+	Elf_Data *data, *symtab = NULL, *rela_orc_ip = NULL;
+	struct elf dummy_elf = {};
+
+
+	objname = _objname;
+
+	elf_version(EV_CURRENT);
+
+	fd = open(objname, O_RDONLY);
+	if (fd == -1) {
+		perror("open");
+		return -1;
+	}
+
+	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+	if (!elf) {
+		WARN_ELF("elf_begin");
+		return -1;
+	}
+
+	if (!elf64_getehdr(elf)) {
+		WARN_ELF("elf64_getehdr");
+		return -1;
+	}
+	memcpy(&dummy_elf.ehdr, elf64_getehdr(elf), sizeof(dummy_elf.ehdr));
+
+	if (elf_getshdrnum(elf, &nr_sections)) {
+		WARN_ELF("elf_getshdrnum");
+		return -1;
+	}
+
+	if (elf_getshdrstrndx(elf, &shstrtab_idx)) {
+		WARN_ELF("elf_getshdrstrndx");
+		return -1;
+	}
+
+	for (i = 0; i < nr_sections; i++) {
+		scn = elf_getscn(elf, i);
+		if (!scn) {
+			WARN_ELF("elf_getscn");
+			return -1;
+		}
+
+		if (!gelf_getshdr(scn, &sh)) {
+			WARN_ELF("gelf_getshdr");
+			return -1;
+		}
+
+		name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
+		if (!name) {
+			WARN_ELF("elf_strptr");
+			return -1;
+		}
+
+		data = elf_getdata(scn, NULL);
+		if (!data) {
+			WARN_ELF("elf_getdata");
+			return -1;
+		}
+
+		if (!strcmp(name, ".symtab")) {
+			symtab = data;
+		} else if (!strcmp(name, ".strtab")) {
+			strtab_idx = i;
+		} else if (!strcmp(name, ".orc_unwind")) {
+			orc = data->d_buf;
+			orc_size = sh.sh_size;
+		} else if (!strcmp(name, ".orc_unwind_ip")) {
+			orc_ip = data->d_buf;
+			orc_ip_addr = sh.sh_addr;
+		} else if (!strcmp(name, ".rela.orc_unwind_ip")) {
+			rela_orc_ip = data;
+		}
+	}
+
+	if (!symtab || !strtab_idx || !orc || !orc_ip)
+		return 0;
+
+	if (orc_size % sizeof(*orc) != 0) {
+		WARN("bad .orc_unwind section size");
+		return -1;
+	}
+
+	nr_entries = orc_size / sizeof(*orc);
+	for (i = 0; i < nr_entries; i++) {
+		if (rela_orc_ip) {
+			if (!gelf_getrela(rela_orc_ip, i, &rela)) {
+				WARN_ELF("gelf_getrela");
+				return -1;
+			}
+
+			if (!gelf_getsym(symtab, GELF_R_SYM(rela.r_info), &sym)) {
+				WARN_ELF("gelf_getsym");
+				return -1;
+			}
+
+			if (GELF_ST_TYPE(sym.st_info) == STT_SECTION) {
+				scn = elf_getscn(elf, sym.st_shndx);
+				if (!scn) {
+					WARN_ELF("elf_getscn");
+					return -1;
+				}
+
+				if (!gelf_getshdr(scn, &sh)) {
+					WARN_ELF("gelf_getshdr");
+					return -1;
+				}
+
+				name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
+				if (!name) {
+					WARN_ELF("elf_strptr");
+					return -1;
+				}
+			} else {
+				name = elf_strptr(elf, strtab_idx, sym.st_name);
+				if (!name) {
+					WARN_ELF("elf_strptr");
+					return -1;
+				}
+			}
+
+			printf("%s+%llx:", name, (unsigned long long)rela.r_addend);
+
+		} else {
+			printf("%llx:", (unsigned long long)(orc_ip_addr + (i * sizeof(int)) + orc_ip[i]));
+		}
+
+		printf("type:%s", orc_type_name(orc[i].type));
+
+		printf(" sp:");
+
+		print_reg(orc[i].sp_reg, bswap_if_needed(&dummy_elf, orc[i].sp_offset));
+
+		printf(" bp:");
+
+		print_reg(orc[i].bp_reg, bswap_if_needed(&dummy_elf, orc[i].bp_offset));
+
+		printf(" signal:%d\n", orc[i].signal);
+	}
+
+	elf_end(elf);
+	close(fd);
+
+	return 0;
+}
diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
new file mode 100644
index 0000000000..bae3439088
--- /dev/null
+++ b/tools/objtool/orc_gen.c
@@ -0,0 +1,258 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include <linux/objtool_types.h>
+#include <asm/orc_types.h>
+
+#include <objtool/check.h>
+#include <objtool/warn.h>
+#include <objtool/endianness.h>
+
+static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi,
+			  struct instruction *insn)
+{
+	struct cfi_reg *bp = &cfi->regs[CFI_BP];
+
+	memset(orc, 0, sizeof(*orc));
+
+	if (!cfi) {
+		/*
+		 * This is usually either unreachable nops/traps (which don't
+		 * trigger unreachable instruction warnings), or
+		 * STACK_FRAME_NON_STANDARD functions.
+		 */
+		orc->type = ORC_TYPE_UNDEFINED;
+		return 0;
+	}
+
+	switch (cfi->type) {
+	case UNWIND_HINT_TYPE_UNDEFINED:
+		orc->type = ORC_TYPE_UNDEFINED;
+		return 0;
+	case UNWIND_HINT_TYPE_END_OF_STACK:
+		orc->type = ORC_TYPE_END_OF_STACK;
+		return 0;
+	case UNWIND_HINT_TYPE_CALL:
+		orc->type = ORC_TYPE_CALL;
+		break;
+	case UNWIND_HINT_TYPE_REGS:
+		orc->type = ORC_TYPE_REGS;
+		break;
+	case UNWIND_HINT_TYPE_REGS_PARTIAL:
+		orc->type = ORC_TYPE_REGS_PARTIAL;
+		break;
+	default:
+		WARN_INSN(insn, "unknown unwind hint type %d", cfi->type);
+		return -1;
+	}
+
+	orc->signal = cfi->signal;
+
+	switch (cfi->cfa.base) {
+	case CFI_SP:
+		orc->sp_reg = ORC_REG_SP;
+		break;
+	case CFI_SP_INDIRECT:
+		orc->sp_reg = ORC_REG_SP_INDIRECT;
+		break;
+	case CFI_BP:
+		orc->sp_reg = ORC_REG_BP;
+		break;
+	case CFI_BP_INDIRECT:
+		orc->sp_reg = ORC_REG_BP_INDIRECT;
+		break;
+	case CFI_R10:
+		orc->sp_reg = ORC_REG_R10;
+		break;
+	case CFI_R13:
+		orc->sp_reg = ORC_REG_R13;
+		break;
+	case CFI_DI:
+		orc->sp_reg = ORC_REG_DI;
+		break;
+	case CFI_DX:
+		orc->sp_reg = ORC_REG_DX;
+		break;
+	default:
+		WARN_INSN(insn, "unknown CFA base reg %d", cfi->cfa.base);
+		return -1;
+	}
+
+	switch (bp->base) {
+	case CFI_UNDEFINED:
+		orc->bp_reg = ORC_REG_UNDEFINED;
+		break;
+	case CFI_CFA:
+		orc->bp_reg = ORC_REG_PREV_SP;
+		break;
+	case CFI_BP:
+		orc->bp_reg = ORC_REG_BP;
+		break;
+	default:
+		WARN_INSN(insn, "unknown BP base reg %d", bp->base);
+		return -1;
+	}
+
+	orc->sp_offset = cfi->cfa.offset;
+	orc->bp_offset = bp->offset;
+
+	return 0;
+}
+
+static int write_orc_entry(struct elf *elf, struct section *orc_sec,
+			   struct section *ip_sec, unsigned int idx,
+			   struct section *insn_sec, unsigned long insn_off,
+			   struct orc_entry *o)
+{
+	struct orc_entry *orc;
+
+	/* populate ORC data */
+	orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
+	memcpy(orc, o, sizeof(*orc));
+	orc->sp_offset = bswap_if_needed(elf, orc->sp_offset);
+	orc->bp_offset = bswap_if_needed(elf, orc->bp_offset);
+
+	/* populate reloc for ip */
+	if (!elf_init_reloc_text_sym(elf, ip_sec, idx * sizeof(int), idx,
+				     insn_sec, insn_off))
+		return -1;
+
+	return 0;
+}
+
+struct orc_list_entry {
+	struct list_head list;
+	struct orc_entry orc;
+	struct section *insn_sec;
+	unsigned long insn_off;
+};
+
+static int orc_list_add(struct list_head *orc_list, struct orc_entry *orc,
+			struct section *sec, unsigned long offset)
+{
+	struct orc_list_entry *entry = malloc(sizeof(*entry));
+
+	if (!entry) {
+		WARN("malloc failed");
+		return -1;
+	}
+
+	entry->orc	= *orc;
+	entry->insn_sec = sec;
+	entry->insn_off = offset;
+
+	list_add_tail(&entry->list, orc_list);
+	return 0;
+}
+
+static unsigned long alt_group_len(struct alt_group *alt_group)
+{
+	return alt_group->last_insn->offset +
+	       alt_group->last_insn->len -
+	       alt_group->first_insn->offset;
+}
+
+int orc_create(struct objtool_file *file)
+{
+	struct section *sec, *orc_sec;
+	unsigned int nr = 0, idx = 0;
+	struct orc_list_entry *entry;
+	struct list_head orc_list;
+
+	struct orc_entry null = { .type = ORC_TYPE_UNDEFINED };
+
+	/* Build a deduplicated list of ORC entries: */
+	INIT_LIST_HEAD(&orc_list);
+	for_each_sec(file, sec) {
+		struct orc_entry orc, prev_orc = {0};
+		struct instruction *insn;
+		bool empty = true;
+
+		if (!sec->text)
+			continue;
+
+		sec_for_each_insn(file, sec, insn) {
+			struct alt_group *alt_group = insn->alt_group;
+			int i;
+
+			if (!alt_group) {
+				if (init_orc_entry(&orc, insn->cfi, insn))
+					return -1;
+				if (!memcmp(&prev_orc, &orc, sizeof(orc)))
+					continue;
+				if (orc_list_add(&orc_list, &orc, sec,
+						 insn->offset))
+					return -1;
+				nr++;
+				prev_orc = orc;
+				empty = false;
+				continue;
+			}
+
+			/*
+			 * Alternatives can have different stack layout
+			 * possibilities (but they shouldn't conflict).
+			 * Instead of traversing the instructions, use the
+			 * alt_group's flattened byte-offset-addressed CFI
+			 * array.
+			 */
+			for (i = 0; i < alt_group_len(alt_group); i++) {
+				struct cfi_state *cfi = alt_group->cfi[i];
+				if (!cfi)
+					continue;
+				/* errors are reported on the original insn */
+				if (init_orc_entry(&orc, cfi, insn))
+					return -1;
+				if (!memcmp(&prev_orc, &orc, sizeof(orc)))
+					continue;
+				if (orc_list_add(&orc_list, &orc, insn->sec,
+						 insn->offset + i))
+					return -1;
+				nr++;
+				prev_orc = orc;
+				empty = false;
+			}
+
+			/* Skip to the end of the alt_group */
+			insn = alt_group->last_insn;
+		}
+
+		/* Add a section terminator */
+		if (!empty) {
+			orc_list_add(&orc_list, &null, sec, sec->sh.sh_size);
+			nr++;
+		}
+	}
+	if (!nr)
+		return 0;
+
+	/* Create .orc_unwind, .orc_unwind_ip and .rela.orc_unwind_ip sections: */
+	sec = find_section_by_name(file->elf, ".orc_unwind");
+	if (sec) {
+		WARN("file already has .orc_unwind section, skipping");
+		return -1;
+	}
+	orc_sec = elf_create_section(file->elf, ".orc_unwind",
+				     sizeof(struct orc_entry), nr);
+	if (!orc_sec)
+		return -1;
+
+	sec = elf_create_section_pair(file->elf, ".orc_unwind_ip", sizeof(int), nr, nr);
+	if (!sec)
+		return -1;
+
+	/* Write ORC entries to sections: */
+	list_for_each_entry(entry, &orc_list, list) {
+		if (write_orc_entry(file->elf, orc_sec, sec, idx++,
+				    entry->insn_sec, entry->insn_off,
+				    &entry->orc))
+			return -1;
+	}
+
+	return 0;
+}
diff --git a/tools/objtool/special.c b/tools/objtool/special.c
new file mode 100644
index 0000000000..91b1950f5b
--- /dev/null
+++ b/tools/objtool/special.c
@@ -0,0 +1,182 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+/*
+ * This file reads all the special sections which have alternate instructions
+ * which can be patched in or redirected to at runtime.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include <arch/special.h>
+#include <objtool/builtin.h>
+#include <objtool/special.h>
+#include <objtool/warn.h>
+#include <objtool/endianness.h>
+
+struct special_entry {
+	const char *sec;
+	bool group, jump_or_nop;
+	unsigned char size, orig, new;
+	unsigned char orig_len, new_len; /* group only */
+	unsigned char feature; /* ALTERNATIVE macro CPU feature */
+	unsigned char key; /* jump_label key */
+};
+
+static const struct special_entry entries[] = {
+	{
+		.sec = ".altinstructions",
+		.group = true,
+		.size = ALT_ENTRY_SIZE,
+		.orig = ALT_ORIG_OFFSET,
+		.orig_len = ALT_ORIG_LEN_OFFSET,
+		.new = ALT_NEW_OFFSET,
+		.new_len = ALT_NEW_LEN_OFFSET,
+		.feature = ALT_FEATURE_OFFSET,
+	},
+	{
+		.sec = "__jump_table",
+		.jump_or_nop = true,
+		.size = JUMP_ENTRY_SIZE,
+		.orig = JUMP_ORIG_OFFSET,
+		.new = JUMP_NEW_OFFSET,
+		.key = JUMP_KEY_OFFSET,
+	},
+	{
+		.sec = "__ex_table",
+		.size = EX_ENTRY_SIZE,
+		.orig = EX_ORIG_OFFSET,
+		.new = EX_NEW_OFFSET,
+	},
+	{},
+};
+
+void __weak arch_handle_alternative(unsigned short feature, struct special_alt *alt)
+{
+}
+
+static void reloc_to_sec_off(struct reloc *reloc, struct section **sec,
+			     unsigned long *off)
+{
+	*sec = reloc->sym->sec;
+	*off = reloc->sym->offset + reloc_addend(reloc);
+}
+
+static int get_alt_entry(struct elf *elf, const struct special_entry *entry,
+			 struct section *sec, int idx,
+			 struct special_alt *alt)
+{
+	struct reloc *orig_reloc, *new_reloc;
+	unsigned long offset;
+
+	offset = idx * entry->size;
+
+	alt->group = entry->group;
+	alt->jump_or_nop = entry->jump_or_nop;
+
+	if (alt->group) {
+		alt->orig_len = *(unsigned char *)(sec->data->d_buf + offset +
+						   entry->orig_len);
+		alt->new_len = *(unsigned char *)(sec->data->d_buf + offset +
+						  entry->new_len);
+	}
+
+	if (entry->feature) {
+		unsigned short feature;
+
+		feature = bswap_if_needed(elf,
+					  *(unsigned short *)(sec->data->d_buf +
+							      offset +
+							      entry->feature));
+		arch_handle_alternative(feature, alt);
+	}
+
+	orig_reloc = find_reloc_by_dest(elf, sec, offset + entry->orig);
+	if (!orig_reloc) {
+		WARN_FUNC("can't find orig reloc", sec, offset + entry->orig);
+		return -1;
+	}
+
+	reloc_to_sec_off(orig_reloc, &alt->orig_sec, &alt->orig_off);
+
+	if (!entry->group || alt->new_len) {
+		new_reloc = find_reloc_by_dest(elf, sec, offset + entry->new);
+		if (!new_reloc) {
+			WARN_FUNC("can't find new reloc",
+				  sec, offset + entry->new);
+			return -1;
+		}
+
+		reloc_to_sec_off(new_reloc, &alt->new_sec, &alt->new_off);
+
+		/* _ASM_EXTABLE_EX hack */
+		if (alt->new_off >= 0x7ffffff0)
+			alt->new_off -= 0x7ffffff0;
+	}
+
+	if (entry->key) {
+		struct reloc *key_reloc;
+
+		key_reloc = find_reloc_by_dest(elf, sec, offset + entry->key);
+		if (!key_reloc) {
+			WARN_FUNC("can't find key reloc",
+				  sec, offset + entry->key);
+			return -1;
+		}
+		alt->key_addend = reloc_addend(key_reloc);
+	}
+
+	return 0;
+}
+
+/*
+ * Read all the special sections and create a list of special_alt structs which
+ * describe all the alternate instructions which can be patched in or
+ * redirected to at runtime.
+ */
+int special_get_alts(struct elf *elf, struct list_head *alts)
+{
+	const struct special_entry *entry;
+	struct section *sec;
+	unsigned int nr_entries;
+	struct special_alt *alt;
+	int idx, ret;
+
+	INIT_LIST_HEAD(alts);
+
+	for (entry = entries; entry->sec; entry++) {
+		sec = find_section_by_name(elf, entry->sec);
+		if (!sec)
+			continue;
+
+		if (sec->sh.sh_size % entry->size != 0) {
+			WARN("%s size not a multiple of %d",
+			     sec->name, entry->size);
+			return -1;
+		}
+
+		nr_entries = sec->sh.sh_size / entry->size;
+
+		for (idx = 0; idx < nr_entries; idx++) {
+			alt = malloc(sizeof(*alt));
+			if (!alt) {
+				WARN("malloc failed");
+				return -1;
+			}
+			memset(alt, 0, sizeof(*alt));
+
+			ret = get_alt_entry(elf, entry, sec, idx, alt);
+			if (ret > 0)
+				continue;
+			if (ret < 0)
+				return ret;
+
+			list_add_tail(&alt->list, alts);
+		}
+	}
+
+	return 0;
+}
diff --git a/tools/objtool/sync-check.sh b/tools/objtool/sync-check.sh
new file mode 100755
index 0000000000..81d120d054
--- /dev/null
+++ b/tools/objtool/sync-check.sh
@@ -0,0 +1,75 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+if [ -z "$SRCARCH" ]; then
+	echo 'sync-check.sh: error: missing $SRCARCH environment variable' >&2
+	exit 1
+fi
+
+FILES="include/linux/objtool_types.h"
+
+if [ "$SRCARCH" = "x86" ]; then
+FILES="$FILES
+arch/x86/include/asm/nops.h
+arch/x86/include/asm/inat_types.h
+arch/x86/include/asm/orc_types.h
+arch/x86/include/asm/emulate_prefix.h
+arch/x86/lib/x86-opcode-map.txt
+arch/x86/tools/gen-insn-attr-x86.awk
+include/linux/static_call_types.h
+"
+
+SYNC_CHECK_FILES='
+arch/x86/include/asm/inat.h
+arch/x86/include/asm/insn.h
+arch/x86/lib/inat.c
+arch/x86/lib/insn.c
+'
+fi
+
+check_2 () {
+  file1=$1
+  file2=$2
+
+  shift
+  shift
+
+  cmd="diff $* $file1 $file2 > /dev/null"
+
+  test -f $file2 && {
+    eval $cmd || {
+      echo "Warning: Kernel ABI header at '$file1' differs from latest version at '$file2'" >&2
+      echo diff -u $file1 $file2
+    }
+  }
+}
+
+check () {
+  file=$1
+
+  shift
+
+  check_2 tools/$file $file $*
+}
+
+if [ ! -d ../../kernel ] || [ ! -d ../../tools ] || [ ! -d ../objtool ]; then
+	exit 0
+fi
+
+cd ../..
+
+while read -r file_entry; do
+    if [ -z "$file_entry" ]; then
+	continue
+    fi
+
+    check $file_entry
+done <<EOF
+$FILES
+EOF
+
+if [ "$SRCARCH" = "x86" ]; then
+	for i in $SYNC_CHECK_FILES; do
+		check $i '-I "^.*\/\*.*__ignore_sync_check__.*\*\/.*$"'
+	done
+fi
diff --git a/tools/objtool/weak.c b/tools/objtool/weak.c
new file mode 100644
index 0000000000..d83f607733
--- /dev/null
+++ b/tools/objtool/weak.c
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2020 Matt Helsley <mhelsley@vmware.com>
+ * Weak definitions necessary to compile objtool without
+ * some subcommands (e.g. check, orc).
+ */
+
+#include <stdbool.h>
+#include <errno.h>
+#include <objtool/objtool.h>
+
+#define UNSUPPORTED(name)						\
+({									\
+	fprintf(stderr, "error: objtool: " name " not implemented\n");	\
+	return ENOSYS;							\
+})
+
+int __weak orc_dump(const char *_objname)
+{
+	UNSUPPORTED("ORC");
+}
+
+int __weak orc_create(struct objtool_file *file)
+{
+	UNSUPPORTED("ORC");
+}