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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /tools/testing/selftests/x86
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/testing/selftests/x86')
-rw-r--r--tools/testing/selftests/x86/.gitignore15
-rw-r--r--tools/testing/selftests/x86/Makefile111
-rw-r--r--tools/testing/selftests/x86/amx.c955
-rwxr-xr-xtools/testing/selftests/x86/check_cc.sh16
-rw-r--r--tools/testing/selftests/x86/check_initial_reg_state.c101
-rw-r--r--tools/testing/selftests/x86/corrupt_xstate_header.c102
-rw-r--r--tools/testing/selftests/x86/entry_from_vm86.c348
-rw-r--r--tools/testing/selftests/x86/fsgsbase.c686
-rw-r--r--tools/testing/selftests/x86/fsgsbase_restore.c245
-rw-r--r--tools/testing/selftests/x86/helpers.h25
-rw-r--r--tools/testing/selftests/x86/ioperm.c185
-rw-r--r--tools/testing/selftests/x86/iopl.c281
-rw-r--r--tools/testing/selftests/x86/ldt_gdt.c927
-rw-r--r--tools/testing/selftests/x86/mov_ss_trap.c286
-rw-r--r--tools/testing/selftests/x86/ptrace_syscall.c430
-rw-r--r--tools/testing/selftests/x86/raw_syscall_helper_32.S49
-rw-r--r--tools/testing/selftests/x86/sigaltstack.c128
-rw-r--r--tools/testing/selftests/x86/sigreturn.c875
-rw-r--r--tools/testing/selftests/x86/single_step_syscall.c242
-rw-r--r--tools/testing/selftests/x86/syscall_arg_fault.c236
-rw-r--r--tools/testing/selftests/x86/syscall_nt.c96
-rw-r--r--tools/testing/selftests/x86/syscall_numbering.c482
-rw-r--r--tools/testing/selftests/x86/sysret_rip.c187
-rw-r--r--tools/testing/selftests/x86/sysret_ss_attrs.c104
-rw-r--r--tools/testing/selftests/x86/test_FCMOV.c94
-rw-r--r--tools/testing/selftests/x86/test_FCOMI.c332
-rw-r--r--tools/testing/selftests/x86/test_FISTTP.c138
-rw-r--r--tools/testing/selftests/x86/test_mremap_vdso.c107
-rw-r--r--tools/testing/selftests/x86/test_syscall_vdso.c400
-rw-r--r--tools/testing/selftests/x86/test_vsyscall.c583
-rw-r--r--tools/testing/selftests/x86/thunks.S61
-rw-r--r--tools/testing/selftests/x86/thunks_32.S49
-rw-r--r--tools/testing/selftests/x86/trivial_32bit_program.c18
-rw-r--r--tools/testing/selftests/x86/trivial_64bit_program.c18
-rw-r--r--tools/testing/selftests/x86/trivial_program.c10
-rw-r--r--tools/testing/selftests/x86/unwind_vdso.c183
-rw-r--r--tools/testing/selftests/x86/vdso_restorer.c95
37 files changed, 9200 insertions, 0 deletions
diff --git a/tools/testing/selftests/x86/.gitignore b/tools/testing/selftests/x86/.gitignore
new file mode 100644
index 000000000..1aaef5bf1
--- /dev/null
+++ b/tools/testing/selftests/x86/.gitignore
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0-only
+*_32
+*_64
+single_step_syscall
+sysret_ss_attrs
+syscall_nt
+ptrace_syscall
+test_mremap_vdso
+check_initial_reg_state
+sigreturn
+ldt_gdt
+iopl
+mpx-mini-test
+ioperm
+test_vdso
diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
new file mode 100644
index 000000000..ca9374b56
--- /dev/null
+++ b/tools/testing/selftests/x86/Makefile
@@ -0,0 +1,111 @@
+# SPDX-License-Identifier: GPL-2.0
+all:
+
+include ../lib.mk
+
+.PHONY: all all_32 all_64 warn_32bit_failure clean
+
+UNAME_M := $(shell uname -m)
+CAN_BUILD_I386 := $(shell ./check_cc.sh "$(CC)" trivial_32bit_program.c -m32)
+CAN_BUILD_X86_64 := $(shell ./check_cc.sh "$(CC)" trivial_64bit_program.c)
+CAN_BUILD_WITH_NOPIE := $(shell ./check_cc.sh "$(CC)" trivial_program.c -no-pie)
+
+TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt test_mremap_vdso \
+ check_initial_reg_state sigreturn iopl ioperm \
+ test_vsyscall mov_ss_trap \
+ syscall_arg_fault fsgsbase_restore sigaltstack
+TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \
+ test_FCMOV test_FCOMI test_FISTTP \
+ vdso_restorer
+TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip syscall_numbering \
+ corrupt_xstate_header amx
+# Some selftests require 32bit support enabled also on 64bit systems
+TARGETS_C_32BIT_NEEDED := ldt_gdt ptrace_syscall
+
+TARGETS_C_32BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_32BIT_ONLY) $(TARGETS_C_32BIT_NEEDED)
+TARGETS_C_64BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_64BIT_ONLY)
+ifeq ($(CAN_BUILD_I386)$(CAN_BUILD_X86_64),11)
+TARGETS_C_64BIT_ALL += $(TARGETS_C_32BIT_NEEDED)
+endif
+
+BINARIES_32 := $(TARGETS_C_32BIT_ALL:%=%_32)
+BINARIES_64 := $(TARGETS_C_64BIT_ALL:%=%_64)
+
+BINARIES_32 := $(patsubst %,$(OUTPUT)/%,$(BINARIES_32))
+BINARIES_64 := $(patsubst %,$(OUTPUT)/%,$(BINARIES_64))
+
+CFLAGS := -O2 -g -std=gnu99 -pthread -Wall $(KHDR_INCLUDES)
+
+# call32_from_64 in thunks.S uses absolute addresses.
+ifeq ($(CAN_BUILD_WITH_NOPIE),1)
+CFLAGS += -no-pie
+endif
+
+define gen-target-rule-32
+$(1) $(1)_32: $(OUTPUT)/$(1)_32
+.PHONY: $(1) $(1)_32
+endef
+
+define gen-target-rule-64
+$(1) $(1)_64: $(OUTPUT)/$(1)_64
+.PHONY: $(1) $(1)_64
+endef
+
+ifeq ($(CAN_BUILD_I386),1)
+all: all_32
+TEST_PROGS += $(BINARIES_32)
+EXTRA_CFLAGS += -DCAN_BUILD_32
+$(foreach t,$(TARGETS_C_32BIT_ALL),$(eval $(call gen-target-rule-32,$(t))))
+endif
+
+ifeq ($(CAN_BUILD_X86_64),1)
+all: all_64
+TEST_PROGS += $(BINARIES_64)
+EXTRA_CFLAGS += -DCAN_BUILD_64
+$(foreach t,$(TARGETS_C_64BIT_ALL),$(eval $(call gen-target-rule-64,$(t))))
+endif
+
+all_32: $(BINARIES_32)
+
+all_64: $(BINARIES_64)
+
+EXTRA_CLEAN := $(BINARIES_32) $(BINARIES_64)
+
+$(BINARIES_32): $(OUTPUT)/%_32: %.c helpers.h
+ $(CC) -m32 -o $@ $(CFLAGS) $(EXTRA_CFLAGS) $^ -lrt -ldl -lm
+
+$(BINARIES_64): $(OUTPUT)/%_64: %.c helpers.h
+ $(CC) -m64 -o $@ $(CFLAGS) $(EXTRA_CFLAGS) $^ -lrt -ldl
+
+# x86_64 users should be encouraged to install 32-bit libraries
+ifeq ($(CAN_BUILD_I386)$(CAN_BUILD_X86_64),01)
+all: warn_32bit_failure
+
+warn_32bit_failure:
+ @echo "Warning: you seem to have a broken 32-bit build" 2>&1; \
+ echo "environment. This will reduce test coverage of 64-bit" 2>&1; \
+ echo "kernels. If you are using a Debian-like distribution," 2>&1; \
+ echo "try:"; 2>&1; \
+ echo ""; \
+ echo " apt-get install gcc-multilib libc6-i386 libc6-dev-i386"; \
+ echo ""; \
+ echo "If you are using a Fedora-like distribution, try:"; \
+ echo ""; \
+ echo " yum install glibc-devel.*i686"; \
+ echo ""; \
+ echo "If you are using a SUSE-like distribution, try:"; \
+ echo ""; \
+ echo " zypper install gcc-32bit glibc-devel-static-32bit"; \
+ exit 0;
+endif
+
+# Some tests have additional dependencies.
+$(OUTPUT)/sysret_ss_attrs_64: thunks.S
+$(OUTPUT)/ptrace_syscall_32: raw_syscall_helper_32.S
+$(OUTPUT)/test_syscall_vdso_32: thunks_32.S
+
+# check_initial_reg_state is special: it needs a custom entry, and it
+# needs to be static so that its interpreter doesn't destroy its initial
+# state.
+$(OUTPUT)/check_initial_reg_state_32: CFLAGS += -Wl,-ereal_start -static
+$(OUTPUT)/check_initial_reg_state_64: CFLAGS += -Wl,-ereal_start -static
diff --git a/tools/testing/selftests/x86/amx.c b/tools/testing/selftests/x86/amx.c
new file mode 100644
index 000000000..d884fd69d
--- /dev/null
+++ b/tools/testing/selftests/x86/amx.c
@@ -0,0 +1,955 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+#include <err.h>
+#include <errno.h>
+#include <pthread.h>
+#include <setjmp.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <x86intrin.h>
+
+#include <sys/auxv.h>
+#include <sys/mman.h>
+#include <sys/shm.h>
+#include <sys/ptrace.h>
+#include <sys/syscall.h>
+#include <sys/wait.h>
+#include <sys/uio.h>
+
+#include "../kselftest.h" /* For __cpuid_count() */
+
+#ifndef __x86_64__
+# error This test is 64-bit only
+#endif
+
+#define XSAVE_HDR_OFFSET 512
+#define XSAVE_HDR_SIZE 64
+
+struct xsave_buffer {
+ union {
+ struct {
+ char legacy[XSAVE_HDR_OFFSET];
+ char header[XSAVE_HDR_SIZE];
+ char extended[0];
+ };
+ char bytes[0];
+ };
+};
+
+static inline uint64_t xgetbv(uint32_t index)
+{
+ uint32_t eax, edx;
+
+ asm volatile("xgetbv;"
+ : "=a" (eax), "=d" (edx)
+ : "c" (index));
+ return eax + ((uint64_t)edx << 32);
+}
+
+static inline void xsave(struct xsave_buffer *xbuf, uint64_t rfbm)
+{
+ uint32_t rfbm_lo = rfbm;
+ uint32_t rfbm_hi = rfbm >> 32;
+
+ asm volatile("xsave (%%rdi)"
+ : : "D" (xbuf), "a" (rfbm_lo), "d" (rfbm_hi)
+ : "memory");
+}
+
+static inline void xrstor(struct xsave_buffer *xbuf, uint64_t rfbm)
+{
+ uint32_t rfbm_lo = rfbm;
+ uint32_t rfbm_hi = rfbm >> 32;
+
+ asm volatile("xrstor (%%rdi)"
+ : : "D" (xbuf), "a" (rfbm_lo), "d" (rfbm_hi));
+}
+
+/* err() exits and will not return */
+#define fatal_error(msg, ...) err(1, "[FAIL]\t" msg, ##__VA_ARGS__)
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ fatal_error("sigaction");
+}
+
+static void clearhandler(int sig)
+{
+ struct sigaction sa;
+
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_handler = SIG_DFL;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ fatal_error("sigaction");
+}
+
+#define XFEATURE_XTILECFG 17
+#define XFEATURE_XTILEDATA 18
+#define XFEATURE_MASK_XTILECFG (1 << XFEATURE_XTILECFG)
+#define XFEATURE_MASK_XTILEDATA (1 << XFEATURE_XTILEDATA)
+#define XFEATURE_MASK_XTILE (XFEATURE_MASK_XTILECFG | XFEATURE_MASK_XTILEDATA)
+
+#define CPUID_LEAF1_ECX_XSAVE_MASK (1 << 26)
+#define CPUID_LEAF1_ECX_OSXSAVE_MASK (1 << 27)
+static inline void check_cpuid_xsave(void)
+{
+ uint32_t eax, ebx, ecx, edx;
+
+ /*
+ * CPUID.1:ECX.XSAVE[bit 26] enumerates general
+ * support for the XSAVE feature set, including
+ * XGETBV.
+ */
+ __cpuid_count(1, 0, eax, ebx, ecx, edx);
+ if (!(ecx & CPUID_LEAF1_ECX_XSAVE_MASK))
+ fatal_error("cpuid: no CPU xsave support");
+ if (!(ecx & CPUID_LEAF1_ECX_OSXSAVE_MASK))
+ fatal_error("cpuid: no OS xsave support");
+}
+
+static uint32_t xbuf_size;
+
+static struct {
+ uint32_t xbuf_offset;
+ uint32_t size;
+} xtiledata;
+
+#define CPUID_LEAF_XSTATE 0xd
+#define CPUID_SUBLEAF_XSTATE_USER 0x0
+#define TILE_CPUID 0x1d
+#define TILE_PALETTE_ID 0x1
+
+static void check_cpuid_xtiledata(void)
+{
+ uint32_t eax, ebx, ecx, edx;
+
+ __cpuid_count(CPUID_LEAF_XSTATE, CPUID_SUBLEAF_XSTATE_USER,
+ eax, ebx, ecx, edx);
+
+ /*
+ * EBX enumerates the size (in bytes) required by the XSAVE
+ * instruction for an XSAVE area containing all the user state
+ * components corresponding to bits currently set in XCR0.
+ *
+ * Stash that off so it can be used to allocate buffers later.
+ */
+ xbuf_size = ebx;
+
+ __cpuid_count(CPUID_LEAF_XSTATE, XFEATURE_XTILEDATA,
+ eax, ebx, ecx, edx);
+ /*
+ * eax: XTILEDATA state component size
+ * ebx: XTILEDATA state component offset in user buffer
+ */
+ if (!eax || !ebx)
+ fatal_error("xstate cpuid: invalid tile data size/offset: %d/%d",
+ eax, ebx);
+
+ xtiledata.size = eax;
+ xtiledata.xbuf_offset = ebx;
+}
+
+/* The helpers for managing XSAVE buffer and tile states: */
+
+struct xsave_buffer *alloc_xbuf(void)
+{
+ struct xsave_buffer *xbuf;
+
+ /* XSAVE buffer should be 64B-aligned. */
+ xbuf = aligned_alloc(64, xbuf_size);
+ if (!xbuf)
+ fatal_error("aligned_alloc()");
+ return xbuf;
+}
+
+static inline void clear_xstate_header(struct xsave_buffer *buffer)
+{
+ memset(&buffer->header, 0, sizeof(buffer->header));
+}
+
+static inline uint64_t get_xstatebv(struct xsave_buffer *buffer)
+{
+ /* XSTATE_BV is at the beginning of the header: */
+ return *(uint64_t *)&buffer->header;
+}
+
+static inline void set_xstatebv(struct xsave_buffer *buffer, uint64_t bv)
+{
+ /* XSTATE_BV is at the beginning of the header: */
+ *(uint64_t *)(&buffer->header) = bv;
+}
+
+static void set_rand_tiledata(struct xsave_buffer *xbuf)
+{
+ int *ptr = (int *)&xbuf->bytes[xtiledata.xbuf_offset];
+ int data;
+ int i;
+
+ /*
+ * Ensure that 'data' is never 0. This ensures that
+ * the registers are never in their initial configuration
+ * and thus never tracked as being in the init state.
+ */
+ data = rand() | 1;
+
+ for (i = 0; i < xtiledata.size / sizeof(int); i++, ptr++)
+ *ptr = data;
+}
+
+struct xsave_buffer *stashed_xsave;
+
+static void init_stashed_xsave(void)
+{
+ stashed_xsave = alloc_xbuf();
+ if (!stashed_xsave)
+ fatal_error("failed to allocate stashed_xsave\n");
+ clear_xstate_header(stashed_xsave);
+}
+
+static void free_stashed_xsave(void)
+{
+ free(stashed_xsave);
+}
+
+/* See 'struct _fpx_sw_bytes' at sigcontext.h */
+#define SW_BYTES_OFFSET 464
+/* N.B. The struct's field name varies so read from the offset. */
+#define SW_BYTES_BV_OFFSET (SW_BYTES_OFFSET + 8)
+
+static inline struct _fpx_sw_bytes *get_fpx_sw_bytes(void *buffer)
+{
+ return (struct _fpx_sw_bytes *)(buffer + SW_BYTES_OFFSET);
+}
+
+static inline uint64_t get_fpx_sw_bytes_features(void *buffer)
+{
+ return *(uint64_t *)(buffer + SW_BYTES_BV_OFFSET);
+}
+
+/* Work around printf() being unsafe in signals: */
+#define SIGNAL_BUF_LEN 1000
+char signal_message_buffer[SIGNAL_BUF_LEN];
+void sig_print(char *msg)
+{
+ int left = SIGNAL_BUF_LEN - strlen(signal_message_buffer) - 1;
+
+ strncat(signal_message_buffer, msg, left);
+}
+
+static volatile bool noperm_signaled;
+static int noperm_errs;
+/*
+ * Signal handler for when AMX is used but
+ * permission has not been obtained.
+ */
+static void handle_noperm(int sig, siginfo_t *si, void *ctx_void)
+{
+ ucontext_t *ctx = (ucontext_t *)ctx_void;
+ void *xbuf = ctx->uc_mcontext.fpregs;
+ struct _fpx_sw_bytes *sw_bytes;
+ uint64_t features;
+
+ /* Reset the signal message buffer: */
+ signal_message_buffer[0] = '\0';
+ sig_print("\tAt SIGILL handler,\n");
+
+ if (si->si_code != ILL_ILLOPC) {
+ noperm_errs++;
+ sig_print("[FAIL]\tInvalid signal code.\n");
+ } else {
+ sig_print("[OK]\tValid signal code (ILL_ILLOPC).\n");
+ }
+
+ sw_bytes = get_fpx_sw_bytes(xbuf);
+ /*
+ * Without permission, the signal XSAVE buffer should not
+ * have room for AMX register state (aka. xtiledata).
+ * Check that the size does not overlap with where xtiledata
+ * will reside.
+ *
+ * This also implies that no state components *PAST*
+ * XTILEDATA (features >=19) can be present in the buffer.
+ */
+ if (sw_bytes->xstate_size <= xtiledata.xbuf_offset) {
+ sig_print("[OK]\tValid xstate size\n");
+ } else {
+ noperm_errs++;
+ sig_print("[FAIL]\tInvalid xstate size\n");
+ }
+
+ features = get_fpx_sw_bytes_features(xbuf);
+ /*
+ * Without permission, the XTILEDATA feature
+ * bit should not be set.
+ */
+ if ((features & XFEATURE_MASK_XTILEDATA) == 0) {
+ sig_print("[OK]\tValid xstate mask\n");
+ } else {
+ noperm_errs++;
+ sig_print("[FAIL]\tInvalid xstate mask\n");
+ }
+
+ noperm_signaled = true;
+ ctx->uc_mcontext.gregs[REG_RIP] += 3; /* Skip the faulting XRSTOR */
+}
+
+/* Return true if XRSTOR is successful; otherwise, false. */
+static inline bool xrstor_safe(struct xsave_buffer *xbuf, uint64_t mask)
+{
+ noperm_signaled = false;
+ xrstor(xbuf, mask);
+
+ /* Print any messages produced by the signal code: */
+ printf("%s", signal_message_buffer);
+ /*
+ * Reset the buffer to make sure any future printing
+ * only outputs new messages:
+ */
+ signal_message_buffer[0] = '\0';
+
+ if (noperm_errs)
+ fatal_error("saw %d errors in noperm signal handler\n", noperm_errs);
+
+ return !noperm_signaled;
+}
+
+/*
+ * Use XRSTOR to populate the XTILEDATA registers with
+ * random data.
+ *
+ * Return true if successful; otherwise, false.
+ */
+static inline bool load_rand_tiledata(struct xsave_buffer *xbuf)
+{
+ clear_xstate_header(xbuf);
+ set_xstatebv(xbuf, XFEATURE_MASK_XTILEDATA);
+ set_rand_tiledata(xbuf);
+ return xrstor_safe(xbuf, XFEATURE_MASK_XTILEDATA);
+}
+
+/* Return XTILEDATA to its initial configuration. */
+static inline void init_xtiledata(void)
+{
+ clear_xstate_header(stashed_xsave);
+ xrstor_safe(stashed_xsave, XFEATURE_MASK_XTILEDATA);
+}
+
+enum expected_result { FAIL_EXPECTED, SUCCESS_EXPECTED };
+
+/* arch_prctl() and sigaltstack() test */
+
+#define ARCH_GET_XCOMP_PERM 0x1022
+#define ARCH_REQ_XCOMP_PERM 0x1023
+
+static void req_xtiledata_perm(void)
+{
+ syscall(SYS_arch_prctl, ARCH_REQ_XCOMP_PERM, XFEATURE_XTILEDATA);
+}
+
+static void validate_req_xcomp_perm(enum expected_result exp)
+{
+ unsigned long bitmask, expected_bitmask;
+ long rc;
+
+ rc = syscall(SYS_arch_prctl, ARCH_GET_XCOMP_PERM, &bitmask);
+ if (rc) {
+ fatal_error("prctl(ARCH_GET_XCOMP_PERM) error: %ld", rc);
+ } else if (!(bitmask & XFEATURE_MASK_XTILECFG)) {
+ fatal_error("ARCH_GET_XCOMP_PERM returns XFEATURE_XTILECFG off.");
+ }
+
+ rc = syscall(SYS_arch_prctl, ARCH_REQ_XCOMP_PERM, XFEATURE_XTILEDATA);
+ if (exp == FAIL_EXPECTED) {
+ if (rc) {
+ printf("[OK]\tARCH_REQ_XCOMP_PERM saw expected failure..\n");
+ return;
+ }
+
+ fatal_error("ARCH_REQ_XCOMP_PERM saw unexpected success.\n");
+ } else if (rc) {
+ fatal_error("ARCH_REQ_XCOMP_PERM saw unexpected failure.\n");
+ }
+
+ expected_bitmask = bitmask | XFEATURE_MASK_XTILEDATA;
+
+ rc = syscall(SYS_arch_prctl, ARCH_GET_XCOMP_PERM, &bitmask);
+ if (rc) {
+ fatal_error("prctl(ARCH_GET_XCOMP_PERM) error: %ld", rc);
+ } else if (bitmask != expected_bitmask) {
+ fatal_error("ARCH_REQ_XCOMP_PERM set a wrong bitmask: %lx, expected: %lx.\n",
+ bitmask, expected_bitmask);
+ } else {
+ printf("\tARCH_REQ_XCOMP_PERM is successful.\n");
+ }
+}
+
+static void validate_xcomp_perm(enum expected_result exp)
+{
+ bool load_success = load_rand_tiledata(stashed_xsave);
+
+ if (exp == FAIL_EXPECTED) {
+ if (load_success) {
+ noperm_errs++;
+ printf("[FAIL]\tLoad tiledata succeeded.\n");
+ } else {
+ printf("[OK]\tLoad tiledata failed.\n");
+ }
+ } else if (exp == SUCCESS_EXPECTED) {
+ if (load_success) {
+ printf("[OK]\tLoad tiledata succeeded.\n");
+ } else {
+ noperm_errs++;
+ printf("[FAIL]\tLoad tiledata failed.\n");
+ }
+ }
+}
+
+#ifndef AT_MINSIGSTKSZ
+# define AT_MINSIGSTKSZ 51
+#endif
+
+static void *alloc_altstack(unsigned int size)
+{
+ void *altstack;
+
+ altstack = mmap(NULL, size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
+
+ if (altstack == MAP_FAILED)
+ fatal_error("mmap() for altstack");
+
+ return altstack;
+}
+
+static void setup_altstack(void *addr, unsigned long size, enum expected_result exp)
+{
+ stack_t ss;
+ int rc;
+
+ memset(&ss, 0, sizeof(ss));
+ ss.ss_size = size;
+ ss.ss_sp = addr;
+
+ rc = sigaltstack(&ss, NULL);
+
+ if (exp == FAIL_EXPECTED) {
+ if (rc) {
+ printf("[OK]\tsigaltstack() failed.\n");
+ } else {
+ fatal_error("sigaltstack() succeeded unexpectedly.\n");
+ }
+ } else if (rc) {
+ fatal_error("sigaltstack()");
+ }
+}
+
+static void test_dynamic_sigaltstack(void)
+{
+ unsigned int small_size, enough_size;
+ unsigned long minsigstksz;
+ void *altstack;
+
+ minsigstksz = getauxval(AT_MINSIGSTKSZ);
+ printf("\tAT_MINSIGSTKSZ = %lu\n", minsigstksz);
+ /*
+ * getauxval() itself can return 0 for failure or
+ * success. But, in this case, AT_MINSIGSTKSZ
+ * will always return a >=0 value if implemented.
+ * Just check for 0.
+ */
+ if (minsigstksz == 0) {
+ printf("no support for AT_MINSIGSTKSZ, skipping sigaltstack tests\n");
+ return;
+ }
+
+ enough_size = minsigstksz * 2;
+
+ altstack = alloc_altstack(enough_size);
+ printf("\tAllocate memory for altstack (%u bytes).\n", enough_size);
+
+ /*
+ * Try setup_altstack() with a size which can not fit
+ * XTILEDATA. ARCH_REQ_XCOMP_PERM should fail.
+ */
+ small_size = minsigstksz - xtiledata.size;
+ printf("\tAfter sigaltstack() with small size (%u bytes).\n", small_size);
+ setup_altstack(altstack, small_size, SUCCESS_EXPECTED);
+ validate_req_xcomp_perm(FAIL_EXPECTED);
+
+ /*
+ * Try setup_altstack() with a size derived from
+ * AT_MINSIGSTKSZ. It should be more than large enough
+ * and thus ARCH_REQ_XCOMP_PERM should succeed.
+ */
+ printf("\tAfter sigaltstack() with enough size (%u bytes).\n", enough_size);
+ setup_altstack(altstack, enough_size, SUCCESS_EXPECTED);
+ validate_req_xcomp_perm(SUCCESS_EXPECTED);
+
+ /*
+ * Try to coerce setup_altstack() to again accept a
+ * too-small altstack. This ensures that big-enough
+ * sigaltstacks can not shrink to a too-small value
+ * once XTILEDATA permission is established.
+ */
+ printf("\tThen, sigaltstack() with small size (%u bytes).\n", small_size);
+ setup_altstack(altstack, small_size, FAIL_EXPECTED);
+}
+
+static void test_dynamic_state(void)
+{
+ pid_t parent, child, grandchild;
+
+ parent = fork();
+ if (parent < 0) {
+ /* fork() failed */
+ fatal_error("fork");
+ } else if (parent > 0) {
+ int status;
+ /* fork() succeeded. Now in the parent. */
+
+ wait(&status);
+ if (!WIFEXITED(status) || WEXITSTATUS(status))
+ fatal_error("arch_prctl test parent exit");
+ return;
+ }
+ /* fork() succeeded. Now in the child . */
+
+ printf("[RUN]\tCheck ARCH_REQ_XCOMP_PERM around process fork() and sigaltack() test.\n");
+
+ printf("\tFork a child.\n");
+ child = fork();
+ if (child < 0) {
+ fatal_error("fork");
+ } else if (child > 0) {
+ int status;
+
+ wait(&status);
+ if (!WIFEXITED(status) || WEXITSTATUS(status))
+ fatal_error("arch_prctl test child exit");
+ _exit(0);
+ }
+
+ /*
+ * The permission request should fail without an
+ * XTILEDATA-compatible signal stack
+ */
+ printf("\tTest XCOMP_PERM at child.\n");
+ validate_xcomp_perm(FAIL_EXPECTED);
+
+ /*
+ * Set up an XTILEDATA-compatible signal stack and
+ * also obtain permission to populate XTILEDATA.
+ */
+ printf("\tTest dynamic sigaltstack at child:\n");
+ test_dynamic_sigaltstack();
+
+ /* Ensure that XTILEDATA can be populated. */
+ printf("\tTest XCOMP_PERM again at child.\n");
+ validate_xcomp_perm(SUCCESS_EXPECTED);
+
+ printf("\tFork a grandchild.\n");
+ grandchild = fork();
+ if (grandchild < 0) {
+ /* fork() failed */
+ fatal_error("fork");
+ } else if (!grandchild) {
+ /* fork() succeeded. Now in the (grand)child. */
+ printf("\tTest XCOMP_PERM at grandchild.\n");
+
+ /*
+ * Ensure that the grandchild inherited
+ * permission and a compatible sigaltstack:
+ */
+ validate_xcomp_perm(SUCCESS_EXPECTED);
+ } else {
+ int status;
+ /* fork() succeeded. Now in the parent. */
+
+ wait(&status);
+ if (!WIFEXITED(status) || WEXITSTATUS(status))
+ fatal_error("fork test grandchild");
+ }
+
+ _exit(0);
+}
+
+static inline int __compare_tiledata_state(struct xsave_buffer *xbuf1, struct xsave_buffer *xbuf2)
+{
+ return memcmp(&xbuf1->bytes[xtiledata.xbuf_offset],
+ &xbuf2->bytes[xtiledata.xbuf_offset],
+ xtiledata.size);
+}
+
+/*
+ * Save current register state and compare it to @xbuf1.'
+ *
+ * Returns false if @xbuf1 matches the registers.
+ * Returns true if @xbuf1 differs from the registers.
+ */
+static inline bool __validate_tiledata_regs(struct xsave_buffer *xbuf1)
+{
+ struct xsave_buffer *xbuf2;
+ int ret;
+
+ xbuf2 = alloc_xbuf();
+ if (!xbuf2)
+ fatal_error("failed to allocate XSAVE buffer\n");
+
+ xsave(xbuf2, XFEATURE_MASK_XTILEDATA);
+ ret = __compare_tiledata_state(xbuf1, xbuf2);
+
+ free(xbuf2);
+
+ if (ret == 0)
+ return false;
+ return true;
+}
+
+static inline void validate_tiledata_regs_same(struct xsave_buffer *xbuf)
+{
+ int ret = __validate_tiledata_regs(xbuf);
+
+ if (ret != 0)
+ fatal_error("TILEDATA registers changed");
+}
+
+static inline void validate_tiledata_regs_changed(struct xsave_buffer *xbuf)
+{
+ int ret = __validate_tiledata_regs(xbuf);
+
+ if (ret == 0)
+ fatal_error("TILEDATA registers did not change");
+}
+
+/* tiledata inheritance test */
+
+static void test_fork(void)
+{
+ pid_t child, grandchild;
+
+ child = fork();
+ if (child < 0) {
+ /* fork() failed */
+ fatal_error("fork");
+ } else if (child > 0) {
+ /* fork() succeeded. Now in the parent. */
+ int status;
+
+ wait(&status);
+ if (!WIFEXITED(status) || WEXITSTATUS(status))
+ fatal_error("fork test child");
+ return;
+ }
+ /* fork() succeeded. Now in the child. */
+ printf("[RUN]\tCheck tile data inheritance.\n\tBefore fork(), load tiledata\n");
+
+ load_rand_tiledata(stashed_xsave);
+
+ grandchild = fork();
+ if (grandchild < 0) {
+ /* fork() failed */
+ fatal_error("fork");
+ } else if (grandchild > 0) {
+ /* fork() succeeded. Still in the first child. */
+ int status;
+
+ wait(&status);
+ if (!WIFEXITED(status) || WEXITSTATUS(status))
+ fatal_error("fork test grand child");
+ _exit(0);
+ }
+ /* fork() succeeded. Now in the (grand)child. */
+
+ /*
+ * TILEDATA registers are not preserved across fork().
+ * Ensure that their value has changed:
+ */
+ validate_tiledata_regs_changed(stashed_xsave);
+
+ _exit(0);
+}
+
+/* Context switching test */
+
+static struct _ctxtswtest_cfg {
+ unsigned int iterations;
+ unsigned int num_threads;
+} ctxtswtest_config;
+
+struct futex_info {
+ pthread_t thread;
+ int nr;
+ pthread_mutex_t mutex;
+ struct futex_info *next;
+};
+
+static void *check_tiledata(void *info)
+{
+ struct futex_info *finfo = (struct futex_info *)info;
+ struct xsave_buffer *xbuf;
+ int i;
+
+ xbuf = alloc_xbuf();
+ if (!xbuf)
+ fatal_error("unable to allocate XSAVE buffer");
+
+ /*
+ * Load random data into 'xbuf' and then restore
+ * it to the tile registers themselves.
+ */
+ load_rand_tiledata(xbuf);
+ for (i = 0; i < ctxtswtest_config.iterations; i++) {
+ pthread_mutex_lock(&finfo->mutex);
+
+ /*
+ * Ensure the register values have not
+ * diverged from those recorded in 'xbuf'.
+ */
+ validate_tiledata_regs_same(xbuf);
+
+ /* Load new, random values into xbuf and registers */
+ load_rand_tiledata(xbuf);
+
+ /*
+ * The last thread's last unlock will be for
+ * thread 0's mutex. However, thread 0 will
+ * have already exited the loop and the mutex
+ * will already be unlocked.
+ *
+ * Because this is not an ERRORCHECK mutex,
+ * that inconsistency will be silently ignored.
+ */
+ pthread_mutex_unlock(&finfo->next->mutex);
+ }
+
+ free(xbuf);
+ /*
+ * Return this thread's finfo, which is
+ * a unique value for this thread.
+ */
+ return finfo;
+}
+
+static int create_threads(int num, struct futex_info *finfo)
+{
+ int i;
+
+ for (i = 0; i < num; i++) {
+ int next_nr;
+
+ finfo[i].nr = i;
+ /*
+ * Thread 'i' will wait on this mutex to
+ * be unlocked. Lock it immediately after
+ * initialization:
+ */
+ pthread_mutex_init(&finfo[i].mutex, NULL);
+ pthread_mutex_lock(&finfo[i].mutex);
+
+ next_nr = (i + 1) % num;
+ finfo[i].next = &finfo[next_nr];
+
+ if (pthread_create(&finfo[i].thread, NULL, check_tiledata, &finfo[i]))
+ fatal_error("pthread_create()");
+ }
+ return 0;
+}
+
+static void affinitize_cpu0(void)
+{
+ cpu_set_t cpuset;
+
+ CPU_ZERO(&cpuset);
+ CPU_SET(0, &cpuset);
+
+ if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
+ fatal_error("sched_setaffinity to CPU 0");
+}
+
+static void test_context_switch(void)
+{
+ struct futex_info *finfo;
+ int i;
+
+ /* Affinitize to one CPU to force context switches */
+ affinitize_cpu0();
+
+ req_xtiledata_perm();
+
+ printf("[RUN]\tCheck tiledata context switches, %d iterations, %d threads.\n",
+ ctxtswtest_config.iterations,
+ ctxtswtest_config.num_threads);
+
+
+ finfo = malloc(sizeof(*finfo) * ctxtswtest_config.num_threads);
+ if (!finfo)
+ fatal_error("malloc()");
+
+ create_threads(ctxtswtest_config.num_threads, finfo);
+
+ /*
+ * This thread wakes up thread 0
+ * Thread 0 will wake up 1
+ * Thread 1 will wake up 2
+ * ...
+ * the last thread will wake up 0
+ *
+ * ... this will repeat for the configured
+ * number of iterations.
+ */
+ pthread_mutex_unlock(&finfo[0].mutex);
+
+ /* Wait for all the threads to finish: */
+ for (i = 0; i < ctxtswtest_config.num_threads; i++) {
+ void *thread_retval;
+ int rc;
+
+ rc = pthread_join(finfo[i].thread, &thread_retval);
+
+ if (rc)
+ fatal_error("pthread_join() failed for thread %d err: %d\n",
+ i, rc);
+
+ if (thread_retval != &finfo[i])
+ fatal_error("unexpected thread retval for thread %d: %p\n",
+ i, thread_retval);
+
+ }
+
+ printf("[OK]\tNo incorrect case was found.\n");
+
+ free(finfo);
+}
+
+/* Ptrace test */
+
+/*
+ * Make sure the ptracee has the expanded kernel buffer on the first
+ * use. Then, initialize the state before performing the state
+ * injection from the ptracer.
+ */
+static inline void ptracee_firstuse_tiledata(void)
+{
+ load_rand_tiledata(stashed_xsave);
+ init_xtiledata();
+}
+
+/*
+ * Ptracer injects the randomized tile data state. It also reads
+ * before and after that, which will execute the kernel's state copy
+ * functions. So, the tester is advised to double-check any emitted
+ * kernel messages.
+ */
+static void ptracer_inject_tiledata(pid_t target)
+{
+ struct xsave_buffer *xbuf;
+ struct iovec iov;
+
+ xbuf = alloc_xbuf();
+ if (!xbuf)
+ fatal_error("unable to allocate XSAVE buffer");
+
+ printf("\tRead the init'ed tiledata via ptrace().\n");
+
+ iov.iov_base = xbuf;
+ iov.iov_len = xbuf_size;
+
+ memset(stashed_xsave, 0, xbuf_size);
+
+ if (ptrace(PTRACE_GETREGSET, target, (uint32_t)NT_X86_XSTATE, &iov))
+ fatal_error("PTRACE_GETREGSET");
+
+ if (!__compare_tiledata_state(stashed_xsave, xbuf))
+ printf("[OK]\tThe init'ed tiledata was read from ptracee.\n");
+ else
+ printf("[FAIL]\tThe init'ed tiledata was not read from ptracee.\n");
+
+ printf("\tInject tiledata via ptrace().\n");
+
+ load_rand_tiledata(xbuf);
+
+ memcpy(&stashed_xsave->bytes[xtiledata.xbuf_offset],
+ &xbuf->bytes[xtiledata.xbuf_offset],
+ xtiledata.size);
+
+ if (ptrace(PTRACE_SETREGSET, target, (uint32_t)NT_X86_XSTATE, &iov))
+ fatal_error("PTRACE_SETREGSET");
+
+ if (ptrace(PTRACE_GETREGSET, target, (uint32_t)NT_X86_XSTATE, &iov))
+ fatal_error("PTRACE_GETREGSET");
+
+ if (!__compare_tiledata_state(stashed_xsave, xbuf))
+ printf("[OK]\tTiledata was correctly written to ptracee.\n");
+ else
+ printf("[FAIL]\tTiledata was not correctly written to ptracee.\n");
+}
+
+static void test_ptrace(void)
+{
+ pid_t child;
+ int status;
+
+ child = fork();
+ if (child < 0) {
+ err(1, "fork");
+ } else if (!child) {
+ if (ptrace(PTRACE_TRACEME, 0, NULL, NULL))
+ err(1, "PTRACE_TRACEME");
+
+ ptracee_firstuse_tiledata();
+
+ raise(SIGTRAP);
+ _exit(0);
+ }
+
+ do {
+ wait(&status);
+ } while (WSTOPSIG(status) != SIGTRAP);
+
+ ptracer_inject_tiledata(child);
+
+ ptrace(PTRACE_DETACH, child, NULL, NULL);
+ wait(&status);
+ if (!WIFEXITED(status) || WEXITSTATUS(status))
+ err(1, "ptrace test");
+}
+
+int main(void)
+{
+ /* Check hardware availability at first */
+ check_cpuid_xsave();
+ check_cpuid_xtiledata();
+
+ init_stashed_xsave();
+ sethandler(SIGILL, handle_noperm, 0);
+
+ test_dynamic_state();
+
+ /* Request permission for the following tests */
+ req_xtiledata_perm();
+
+ test_fork();
+
+ ctxtswtest_config.iterations = 10;
+ ctxtswtest_config.num_threads = 5;
+ test_context_switch();
+
+ test_ptrace();
+
+ clearhandler(SIGILL);
+ free_stashed_xsave();
+
+ return 0;
+}
diff --git a/tools/testing/selftests/x86/check_cc.sh b/tools/testing/selftests/x86/check_cc.sh
new file mode 100755
index 000000000..8c669c0d6
--- /dev/null
+++ b/tools/testing/selftests/x86/check_cc.sh
@@ -0,0 +1,16 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+# check_cc.sh - Helper to test userspace compilation support
+# Copyright (c) 2015 Andrew Lutomirski
+
+CC="$1"
+TESTPROG="$2"
+shift 2
+
+if [ -n "$CC" ] && $CC -o /dev/null "$TESTPROG" -O0 "$@" 2>/dev/null; then
+ echo 1
+else
+ echo 0
+fi
+
+exit 0
diff --git a/tools/testing/selftests/x86/check_initial_reg_state.c b/tools/testing/selftests/x86/check_initial_reg_state.c
new file mode 100644
index 000000000..3bc95f3ed
--- /dev/null
+++ b/tools/testing/selftests/x86/check_initial_reg_state.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * check_initial_reg_state.c - check that execve sets the correct state
+ * Copyright (c) 2014-2016 Andrew Lutomirski
+ */
+
+#define _GNU_SOURCE
+
+#include <stdio.h>
+
+unsigned long ax, bx, cx, dx, si, di, bp, sp, flags;
+unsigned long r8, r9, r10, r11, r12, r13, r14, r15;
+
+asm (
+ ".pushsection .text\n\t"
+ ".type real_start, @function\n\t"
+ ".global real_start\n\t"
+ "real_start:\n\t"
+#ifdef __x86_64__
+ "mov %rax, ax\n\t"
+ "mov %rbx, bx\n\t"
+ "mov %rcx, cx\n\t"
+ "mov %rdx, dx\n\t"
+ "mov %rsi, si\n\t"
+ "mov %rdi, di\n\t"
+ "mov %rbp, bp\n\t"
+ "mov %rsp, sp\n\t"
+ "mov %r8, r8\n\t"
+ "mov %r9, r9\n\t"
+ "mov %r10, r10\n\t"
+ "mov %r11, r11\n\t"
+ "mov %r12, r12\n\t"
+ "mov %r13, r13\n\t"
+ "mov %r14, r14\n\t"
+ "mov %r15, r15\n\t"
+ "pushfq\n\t"
+ "popq flags\n\t"
+#else
+ "mov %eax, ax\n\t"
+ "mov %ebx, bx\n\t"
+ "mov %ecx, cx\n\t"
+ "mov %edx, dx\n\t"
+ "mov %esi, si\n\t"
+ "mov %edi, di\n\t"
+ "mov %ebp, bp\n\t"
+ "mov %esp, sp\n\t"
+ "pushfl\n\t"
+ "popl flags\n\t"
+#endif
+ "jmp _start\n\t"
+ ".size real_start, . - real_start\n\t"
+ ".popsection");
+
+int main()
+{
+ int nerrs = 0;
+
+ if (sp == 0) {
+ printf("[FAIL]\tTest was built incorrectly\n");
+ return 1;
+ }
+
+ if (ax || bx || cx || dx || si || di || bp
+#ifdef __x86_64__
+ || r8 || r9 || r10 || r11 || r12 || r13 || r14 || r15
+#endif
+ ) {
+ printf("[FAIL]\tAll GPRs except SP should be 0\n");
+#define SHOW(x) printf("\t" #x " = 0x%lx\n", x);
+ SHOW(ax);
+ SHOW(bx);
+ SHOW(cx);
+ SHOW(dx);
+ SHOW(si);
+ SHOW(di);
+ SHOW(bp);
+ SHOW(sp);
+#ifdef __x86_64__
+ SHOW(r8);
+ SHOW(r9);
+ SHOW(r10);
+ SHOW(r11);
+ SHOW(r12);
+ SHOW(r13);
+ SHOW(r14);
+ SHOW(r15);
+#endif
+ nerrs++;
+ } else {
+ printf("[OK]\tAll GPRs except SP are 0\n");
+ }
+
+ if (flags != 0x202) {
+ printf("[FAIL]\tFLAGS is 0x%lx, but it should be 0x202\n", flags);
+ nerrs++;
+ } else {
+ printf("[OK]\tFLAGS is 0x202\n");
+ }
+
+ return nerrs ? 1 : 0;
+}
diff --git a/tools/testing/selftests/x86/corrupt_xstate_header.c b/tools/testing/selftests/x86/corrupt_xstate_header.c
new file mode 100644
index 000000000..cf9ce8fbb
--- /dev/null
+++ b/tools/testing/selftests/x86/corrupt_xstate_header.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Corrupt the XSTATE header in a signal frame
+ *
+ * Based on analysis and a test case from Thomas Gleixner.
+ */
+
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sched.h>
+#include <signal.h>
+#include <err.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <sys/wait.h>
+
+#include "../kselftest.h" /* For __cpuid_count() */
+
+static inline int xsave_enabled(void)
+{
+ unsigned int eax, ebx, ecx, edx;
+
+ __cpuid_count(0x1, 0x0, eax, ebx, ecx, edx);
+
+ /* Is CR4.OSXSAVE enabled ? */
+ return ecx & (1U << 27);
+}
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static void sigusr1(int sig, siginfo_t *info, void *uc_void)
+{
+ ucontext_t *uc = uc_void;
+ uint8_t *fpstate = (uint8_t *)uc->uc_mcontext.fpregs;
+ uint64_t *xfeatures = (uint64_t *)(fpstate + 512);
+
+ printf("\tWreck XSTATE header\n");
+ /* Wreck the first reserved bytes in the header */
+ *(xfeatures + 2) = 0xfffffff;
+}
+
+static void sigsegv(int sig, siginfo_t *info, void *uc_void)
+{
+ printf("\tGot SIGSEGV\n");
+}
+
+int main(void)
+{
+ cpu_set_t set;
+
+ sethandler(SIGUSR1, sigusr1, 0);
+ sethandler(SIGSEGV, sigsegv, 0);
+
+ if (!xsave_enabled()) {
+ printf("[SKIP] CR4.OSXSAVE disabled.\n");
+ return 0;
+ }
+
+ CPU_ZERO(&set);
+ CPU_SET(0, &set);
+
+ /*
+ * Enforce that the child runs on the same CPU
+ * which in turn forces a schedule.
+ */
+ sched_setaffinity(getpid(), sizeof(set), &set);
+
+ printf("[RUN]\tSend ourselves a signal\n");
+ raise(SIGUSR1);
+
+ printf("[OK]\tBack from the signal. Now schedule.\n");
+ pid_t child = fork();
+ if (child < 0)
+ err(1, "fork");
+ if (child == 0)
+ return 0;
+ if (child)
+ waitpid(child, NULL, 0);
+ printf("[OK]\tBack in the main thread.\n");
+
+ /*
+ * We could try to confirm that extended state is still preserved
+ * when we schedule. For now, the only indication of failure is
+ * a warning in the kernel logs.
+ */
+
+ return 0;
+}
diff --git a/tools/testing/selftests/x86/entry_from_vm86.c b/tools/testing/selftests/x86/entry_from_vm86.c
new file mode 100644
index 000000000..d1e919b0c
--- /dev/null
+++ b/tools/testing/selftests/x86/entry_from_vm86.c
@@ -0,0 +1,348 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * entry_from_vm86.c - tests kernel entries from vm86 mode
+ * Copyright (c) 2014-2015 Andrew Lutomirski
+ *
+ * This exercises a few paths that need to special-case vm86 mode.
+ */
+
+#define _GNU_SOURCE
+
+#include <assert.h>
+#include <stdlib.h>
+#include <sys/syscall.h>
+#include <sys/signal.h>
+#include <sys/ucontext.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <inttypes.h>
+#include <sys/mman.h>
+#include <err.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <sys/vm86.h>
+
+static unsigned long load_addr = 0x10000;
+static int nerrs = 0;
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static void clearhandler(int sig)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_handler = SIG_DFL;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static sig_atomic_t got_signal;
+
+static void sighandler(int sig, siginfo_t *info, void *ctx_void)
+{
+ ucontext_t *ctx = (ucontext_t*)ctx_void;
+
+ if (ctx->uc_mcontext.gregs[REG_EFL] & X86_EFLAGS_VM ||
+ (ctx->uc_mcontext.gregs[REG_CS] & 3) != 3) {
+ printf("[FAIL]\tSignal frame should not reflect vm86 mode\n");
+ nerrs++;
+ }
+
+ const char *signame;
+ if (sig == SIGSEGV)
+ signame = "SIGSEGV";
+ else if (sig == SIGILL)
+ signame = "SIGILL";
+ else
+ signame = "unexpected signal";
+
+ printf("[INFO]\t%s: FLAGS = 0x%lx, CS = 0x%hx\n", signame,
+ (unsigned long)ctx->uc_mcontext.gregs[REG_EFL],
+ (unsigned short)ctx->uc_mcontext.gregs[REG_CS]);
+
+ got_signal = 1;
+}
+
+asm (
+ ".pushsection .rodata\n\t"
+ ".type vmcode_bound, @object\n\t"
+ "vmcode:\n\t"
+ "vmcode_bound:\n\t"
+ ".code16\n\t"
+ "bound %ax, (2048)\n\t"
+ "int3\n\t"
+ "vmcode_sysenter:\n\t"
+ "sysenter\n\t"
+ "vmcode_syscall:\n\t"
+ "syscall\n\t"
+ "vmcode_sti:\n\t"
+ "sti\n\t"
+ "vmcode_int3:\n\t"
+ "int3\n\t"
+ "vmcode_int80:\n\t"
+ "int $0x80\n\t"
+ "vmcode_popf_hlt:\n\t"
+ "push %ax\n\t"
+ "popf\n\t"
+ "hlt\n\t"
+ "vmcode_umip:\n\t"
+ /* addressing via displacements */
+ "smsw (2052)\n\t"
+ "sidt (2054)\n\t"
+ "sgdt (2060)\n\t"
+ /* addressing via registers */
+ "mov $2066, %bx\n\t"
+ "smsw (%bx)\n\t"
+ "mov $2068, %bx\n\t"
+ "sidt (%bx)\n\t"
+ "mov $2074, %bx\n\t"
+ "sgdt (%bx)\n\t"
+ /* register operands, only for smsw */
+ "smsw %ax\n\t"
+ "mov %ax, (2080)\n\t"
+ "int3\n\t"
+ "vmcode_umip_str:\n\t"
+ "str %eax\n\t"
+ "vmcode_umip_sldt:\n\t"
+ "sldt %eax\n\t"
+ "int3\n\t"
+ ".size vmcode, . - vmcode\n\t"
+ "end_vmcode:\n\t"
+ ".code32\n\t"
+ ".popsection"
+ );
+
+extern unsigned char vmcode[], end_vmcode[];
+extern unsigned char vmcode_bound[], vmcode_sysenter[], vmcode_syscall[],
+ vmcode_sti[], vmcode_int3[], vmcode_int80[], vmcode_popf_hlt[],
+ vmcode_umip[], vmcode_umip_str[], vmcode_umip_sldt[];
+
+/* Returns false if the test was skipped. */
+static bool do_test(struct vm86plus_struct *v86, unsigned long eip,
+ unsigned int rettype, unsigned int retarg,
+ const char *text)
+{
+ long ret;
+
+ printf("[RUN]\t%s from vm86 mode\n", text);
+ v86->regs.eip = eip;
+ ret = vm86(VM86_ENTER, v86);
+
+ if (ret == -1 && (errno == ENOSYS || errno == EPERM)) {
+ printf("[SKIP]\tvm86 %s\n",
+ errno == ENOSYS ? "not supported" : "not allowed");
+ return false;
+ }
+
+ if (VM86_TYPE(ret) == VM86_INTx) {
+ char trapname[32];
+ int trapno = VM86_ARG(ret);
+ if (trapno == 13)
+ strcpy(trapname, "GP");
+ else if (trapno == 5)
+ strcpy(trapname, "BR");
+ else if (trapno == 14)
+ strcpy(trapname, "PF");
+ else
+ sprintf(trapname, "%d", trapno);
+
+ printf("[INFO]\tExited vm86 mode due to #%s\n", trapname);
+ } else if (VM86_TYPE(ret) == VM86_UNKNOWN) {
+ printf("[INFO]\tExited vm86 mode due to unhandled GP fault\n");
+ } else if (VM86_TYPE(ret) == VM86_TRAP) {
+ printf("[INFO]\tExited vm86 mode due to a trap (arg=%ld)\n",
+ VM86_ARG(ret));
+ } else if (VM86_TYPE(ret) == VM86_SIGNAL) {
+ printf("[INFO]\tExited vm86 mode due to a signal\n");
+ } else if (VM86_TYPE(ret) == VM86_STI) {
+ printf("[INFO]\tExited vm86 mode due to STI\n");
+ } else {
+ printf("[INFO]\tExited vm86 mode due to type %ld, arg %ld\n",
+ VM86_TYPE(ret), VM86_ARG(ret));
+ }
+
+ if (rettype == -1 ||
+ (VM86_TYPE(ret) == rettype && VM86_ARG(ret) == retarg)) {
+ printf("[OK]\tReturned correctly\n");
+ } else {
+ printf("[FAIL]\tIncorrect return reason (started at eip = 0x%lx, ended at eip = 0x%lx)\n", eip, v86->regs.eip);
+ nerrs++;
+ }
+
+ return true;
+}
+
+void do_umip_tests(struct vm86plus_struct *vm86, unsigned char *test_mem)
+{
+ struct table_desc {
+ unsigned short limit;
+ unsigned long base;
+ } __attribute__((packed));
+
+ /* Initialize variables with arbitrary values */
+ struct table_desc gdt1 = { .base = 0x3c3c3c3c, .limit = 0x9999 };
+ struct table_desc gdt2 = { .base = 0x1a1a1a1a, .limit = 0xaeae };
+ struct table_desc idt1 = { .base = 0x7b7b7b7b, .limit = 0xf1f1 };
+ struct table_desc idt2 = { .base = 0x89898989, .limit = 0x1313 };
+ unsigned short msw1 = 0x1414, msw2 = 0x2525, msw3 = 3737;
+
+ /* UMIP -- exit with INT3 unless kernel emulation did not trap #GP */
+ do_test(vm86, vmcode_umip - vmcode, VM86_TRAP, 3, "UMIP tests");
+
+ /* Results from displacement-only addressing */
+ msw1 = *(unsigned short *)(test_mem + 2052);
+ memcpy(&idt1, test_mem + 2054, sizeof(idt1));
+ memcpy(&gdt1, test_mem + 2060, sizeof(gdt1));
+
+ /* Results from register-indirect addressing */
+ msw2 = *(unsigned short *)(test_mem + 2066);
+ memcpy(&idt2, test_mem + 2068, sizeof(idt2));
+ memcpy(&gdt2, test_mem + 2074, sizeof(gdt2));
+
+ /* Results when using register operands */
+ msw3 = *(unsigned short *)(test_mem + 2080);
+
+ printf("[INFO]\tResult from SMSW:[0x%04x]\n", msw1);
+ printf("[INFO]\tResult from SIDT: limit[0x%04x]base[0x%08lx]\n",
+ idt1.limit, idt1.base);
+ printf("[INFO]\tResult from SGDT: limit[0x%04x]base[0x%08lx]\n",
+ gdt1.limit, gdt1.base);
+
+ if (msw1 != msw2 || msw1 != msw3)
+ printf("[FAIL]\tAll the results of SMSW should be the same.\n");
+ else
+ printf("[PASS]\tAll the results from SMSW are identical.\n");
+
+ if (memcmp(&gdt1, &gdt2, sizeof(gdt1)))
+ printf("[FAIL]\tAll the results of SGDT should be the same.\n");
+ else
+ printf("[PASS]\tAll the results from SGDT are identical.\n");
+
+ if (memcmp(&idt1, &idt2, sizeof(idt1)))
+ printf("[FAIL]\tAll the results of SIDT should be the same.\n");
+ else
+ printf("[PASS]\tAll the results from SIDT are identical.\n");
+
+ sethandler(SIGILL, sighandler, 0);
+ do_test(vm86, vmcode_umip_str - vmcode, VM86_SIGNAL, 0,
+ "STR instruction");
+ clearhandler(SIGILL);
+
+ sethandler(SIGILL, sighandler, 0);
+ do_test(vm86, vmcode_umip_sldt - vmcode, VM86_SIGNAL, 0,
+ "SLDT instruction");
+ clearhandler(SIGILL);
+}
+
+int main(void)
+{
+ struct vm86plus_struct v86;
+ unsigned char *addr = mmap((void *)load_addr, 4096,
+ PROT_READ | PROT_WRITE | PROT_EXEC,
+ MAP_ANONYMOUS | MAP_PRIVATE, -1,0);
+ if (addr != (unsigned char *)load_addr)
+ err(1, "mmap");
+
+ memcpy(addr, vmcode, end_vmcode - vmcode);
+ addr[2048] = 2;
+ addr[2050] = 3;
+
+ memset(&v86, 0, sizeof(v86));
+
+ v86.regs.cs = load_addr / 16;
+ v86.regs.ss = load_addr / 16;
+ v86.regs.ds = load_addr / 16;
+ v86.regs.es = load_addr / 16;
+
+ /* Use the end of the page as our stack. */
+ v86.regs.esp = 4096;
+
+ assert((v86.regs.cs & 3) == 0); /* Looks like RPL = 0 */
+
+ /* #BR -- should deliver SIG??? */
+ do_test(&v86, vmcode_bound - vmcode, VM86_INTx, 5, "#BR");
+
+ /*
+ * SYSENTER -- should cause #GP or #UD depending on CPU.
+ * Expected return type -1 means that we shouldn't validate
+ * the vm86 return value. This will avoid problems on non-SEP
+ * CPUs.
+ */
+ sethandler(SIGILL, sighandler, 0);
+ do_test(&v86, vmcode_sysenter - vmcode, -1, 0, "SYSENTER");
+ clearhandler(SIGILL);
+
+ /*
+ * SYSCALL would be a disaster in VM86 mode. Fortunately,
+ * there is no kernel that both enables SYSCALL and sets
+ * EFER.SCE, so it's #UD on all systems. But vm86 is
+ * buggy (or has a "feature"), so the SIGILL will actually
+ * be delivered.
+ */
+ sethandler(SIGILL, sighandler, 0);
+ do_test(&v86, vmcode_syscall - vmcode, VM86_SIGNAL, 0, "SYSCALL");
+ clearhandler(SIGILL);
+
+ /* STI with VIP set */
+ v86.regs.eflags |= X86_EFLAGS_VIP;
+ v86.regs.eflags &= ~X86_EFLAGS_IF;
+ do_test(&v86, vmcode_sti - vmcode, VM86_STI, 0, "STI with VIP set");
+
+ /* POPF with VIP set but IF clear: should not trap */
+ v86.regs.eflags = X86_EFLAGS_VIP;
+ v86.regs.eax = 0;
+ do_test(&v86, vmcode_popf_hlt - vmcode, VM86_UNKNOWN, 0, "POPF with VIP set and IF clear");
+
+ /* POPF with VIP set and IF set: should trap */
+ v86.regs.eflags = X86_EFLAGS_VIP;
+ v86.regs.eax = X86_EFLAGS_IF;
+ do_test(&v86, vmcode_popf_hlt - vmcode, VM86_STI, 0, "POPF with VIP and IF set");
+
+ /* POPF with VIP clear and IF set: should not trap */
+ v86.regs.eflags = 0;
+ v86.regs.eax = X86_EFLAGS_IF;
+ do_test(&v86, vmcode_popf_hlt - vmcode, VM86_UNKNOWN, 0, "POPF with VIP clear and IF set");
+
+ v86.regs.eflags = 0;
+
+ /* INT3 -- should cause #BP */
+ do_test(&v86, vmcode_int3 - vmcode, VM86_TRAP, 3, "INT3");
+
+ /* INT80 -- should exit with "INTx 0x80" */
+ v86.regs.eax = (unsigned int)-1;
+ do_test(&v86, vmcode_int80 - vmcode, VM86_INTx, 0x80, "int80");
+
+ /* UMIP -- should exit with INTx 0x80 unless UMIP was not disabled */
+ do_umip_tests(&v86, addr);
+
+ /* Execute a null pointer */
+ v86.regs.cs = 0;
+ v86.regs.ss = 0;
+ sethandler(SIGSEGV, sighandler, 0);
+ got_signal = 0;
+ if (do_test(&v86, 0, VM86_SIGNAL, 0, "Execute null pointer") &&
+ !got_signal) {
+ printf("[FAIL]\tDid not receive SIGSEGV\n");
+ nerrs++;
+ }
+ clearhandler(SIGSEGV);
+
+ /* Make sure nothing explodes if we fork. */
+ if (fork() == 0)
+ return 0;
+
+ return (nerrs == 0 ? 0 : 1);
+}
diff --git a/tools/testing/selftests/x86/fsgsbase.c b/tools/testing/selftests/x86/fsgsbase.c
new file mode 100644
index 000000000..8c780cce9
--- /dev/null
+++ b/tools/testing/selftests/x86/fsgsbase.c
@@ -0,0 +1,686 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * fsgsbase.c, an fsgsbase test
+ * Copyright (c) 2014-2016 Andy Lutomirski
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <err.h>
+#include <sys/user.h>
+#include <asm/prctl.h>
+#include <sys/prctl.h>
+#include <signal.h>
+#include <limits.h>
+#include <sys/ucontext.h>
+#include <sched.h>
+#include <linux/futex.h>
+#include <pthread.h>
+#include <asm/ldt.h>
+#include <sys/mman.h>
+#include <stddef.h>
+#include <sys/ptrace.h>
+#include <sys/wait.h>
+#include <setjmp.h>
+
+#ifndef __x86_64__
+# error This test is 64-bit only
+#endif
+
+static volatile sig_atomic_t want_segv;
+static volatile unsigned long segv_addr;
+
+static unsigned short *shared_scratch;
+
+static int nerrs;
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static void clearhandler(int sig)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_handler = SIG_DFL;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static void sigsegv(int sig, siginfo_t *si, void *ctx_void)
+{
+ ucontext_t *ctx = (ucontext_t*)ctx_void;
+
+ if (!want_segv) {
+ clearhandler(SIGSEGV);
+ return; /* Crash cleanly. */
+ }
+
+ want_segv = false;
+ segv_addr = (unsigned long)si->si_addr;
+
+ ctx->uc_mcontext.gregs[REG_RIP] += 4; /* Skip the faulting mov */
+
+}
+
+static jmp_buf jmpbuf;
+
+static void sigill(int sig, siginfo_t *si, void *ctx_void)
+{
+ siglongjmp(jmpbuf, 1);
+}
+
+static bool have_fsgsbase;
+
+static inline unsigned long rdgsbase(void)
+{
+ unsigned long gsbase;
+
+ asm volatile("rdgsbase %0" : "=r" (gsbase) :: "memory");
+
+ return gsbase;
+}
+
+static inline unsigned long rdfsbase(void)
+{
+ unsigned long fsbase;
+
+ asm volatile("rdfsbase %0" : "=r" (fsbase) :: "memory");
+
+ return fsbase;
+}
+
+static inline void wrgsbase(unsigned long gsbase)
+{
+ asm volatile("wrgsbase %0" :: "r" (gsbase) : "memory");
+}
+
+static inline void wrfsbase(unsigned long fsbase)
+{
+ asm volatile("wrfsbase %0" :: "r" (fsbase) : "memory");
+}
+
+enum which_base { FS, GS };
+
+static unsigned long read_base(enum which_base which)
+{
+ unsigned long offset;
+ /*
+ * Unless we have FSGSBASE, there's no direct way to do this from
+ * user mode. We can get at it indirectly using signals, though.
+ */
+
+ want_segv = true;
+
+ offset = 0;
+ if (which == FS) {
+ /* Use a constant-length instruction here. */
+ asm volatile ("mov %%fs:(%%rcx), %%rax" : : "c" (offset) : "rax");
+ } else {
+ asm volatile ("mov %%gs:(%%rcx), %%rax" : : "c" (offset) : "rax");
+ }
+ if (!want_segv)
+ return segv_addr + offset;
+
+ /*
+ * If that didn't segfault, try the other end of the address space.
+ * Unless we get really unlucky and run into the vsyscall page, this
+ * is guaranteed to segfault.
+ */
+
+ offset = (ULONG_MAX >> 1) + 1;
+ if (which == FS) {
+ asm volatile ("mov %%fs:(%%rcx), %%rax"
+ : : "c" (offset) : "rax");
+ } else {
+ asm volatile ("mov %%gs:(%%rcx), %%rax"
+ : : "c" (offset) : "rax");
+ }
+ if (!want_segv)
+ return segv_addr + offset;
+
+ abort();
+}
+
+static void check_gs_value(unsigned long value)
+{
+ unsigned long base;
+ unsigned short sel;
+
+ printf("[RUN]\tARCH_SET_GS to 0x%lx\n", value);
+ if (syscall(SYS_arch_prctl, ARCH_SET_GS, value) != 0)
+ err(1, "ARCH_SET_GS");
+
+ asm volatile ("mov %%gs, %0" : "=rm" (sel));
+ base = read_base(GS);
+ if (base == value) {
+ printf("[OK]\tGSBASE was set as expected (selector 0x%hx)\n",
+ sel);
+ } else {
+ nerrs++;
+ printf("[FAIL]\tGSBASE was not as expected: got 0x%lx (selector 0x%hx)\n",
+ base, sel);
+ }
+
+ if (syscall(SYS_arch_prctl, ARCH_GET_GS, &base) != 0)
+ err(1, "ARCH_GET_GS");
+ if (base == value) {
+ printf("[OK]\tARCH_GET_GS worked as expected (selector 0x%hx)\n",
+ sel);
+ } else {
+ nerrs++;
+ printf("[FAIL]\tARCH_GET_GS was not as expected: got 0x%lx (selector 0x%hx)\n",
+ base, sel);
+ }
+}
+
+static void mov_0_gs(unsigned long initial_base, bool schedule)
+{
+ unsigned long base, arch_base;
+
+ printf("[RUN]\tARCH_SET_GS to 0x%lx then mov 0 to %%gs%s\n", initial_base, schedule ? " and schedule " : "");
+ if (syscall(SYS_arch_prctl, ARCH_SET_GS, initial_base) != 0)
+ err(1, "ARCH_SET_GS");
+
+ if (schedule)
+ usleep(10);
+
+ asm volatile ("mov %0, %%gs" : : "rm" (0));
+ base = read_base(GS);
+ if (syscall(SYS_arch_prctl, ARCH_GET_GS, &arch_base) != 0)
+ err(1, "ARCH_GET_GS");
+ if (base == arch_base) {
+ printf("[OK]\tGSBASE is 0x%lx\n", base);
+ } else {
+ nerrs++;
+ printf("[FAIL]\tGSBASE changed to 0x%lx but kernel reports 0x%lx\n", base, arch_base);
+ }
+}
+
+static volatile unsigned long remote_base;
+static volatile bool remote_hard_zero;
+static volatile unsigned int ftx;
+
+/*
+ * ARCH_SET_FS/GS(0) may or may not program a selector of zero. HARD_ZERO
+ * means to force the selector to zero to improve test coverage.
+ */
+#define HARD_ZERO 0xa1fa5f343cb85fa4
+
+static void do_remote_base()
+{
+ unsigned long to_set = remote_base;
+ bool hard_zero = false;
+ if (to_set == HARD_ZERO) {
+ to_set = 0;
+ hard_zero = true;
+ }
+
+ if (syscall(SYS_arch_prctl, ARCH_SET_GS, to_set) != 0)
+ err(1, "ARCH_SET_GS");
+
+ if (hard_zero)
+ asm volatile ("mov %0, %%gs" : : "rm" ((unsigned short)0));
+
+ unsigned short sel;
+ asm volatile ("mov %%gs, %0" : "=rm" (sel));
+ printf("\tother thread: ARCH_SET_GS(0x%lx)%s -- sel is 0x%hx\n",
+ to_set, hard_zero ? " and clear gs" : "", sel);
+}
+
+static __thread int set_thread_area_entry_number = -1;
+
+static unsigned short load_gs(void)
+{
+ /*
+ * Sets GS != 0 and GSBASE != 0 but arranges for the kernel to think
+ * that GSBASE == 0 (i.e. thread.gsbase == 0).
+ */
+
+ /* Step 1: tell the kernel that we have GSBASE == 0. */
+ if (syscall(SYS_arch_prctl, ARCH_SET_GS, 0) != 0)
+ err(1, "ARCH_SET_GS");
+
+ /* Step 2: change GSBASE without telling the kernel. */
+ struct user_desc desc = {
+ .entry_number = 0,
+ .base_addr = 0xBAADF00D,
+ .limit = 0xfffff,
+ .seg_32bit = 1,
+ .contents = 0, /* Data, grow-up */
+ .read_exec_only = 0,
+ .limit_in_pages = 1,
+ .seg_not_present = 0,
+ .useable = 0
+ };
+ if (syscall(SYS_modify_ldt, 1, &desc, sizeof(desc)) == 0) {
+ printf("\tusing LDT slot 0\n");
+ asm volatile ("mov %0, %%gs" : : "rm" ((unsigned short)0x7));
+ return 0x7;
+ } else {
+ /* No modify_ldt for us (configured out, perhaps) */
+
+ struct user_desc *low_desc = mmap(
+ NULL, sizeof(desc),
+ PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_32BIT, -1, 0);
+ memcpy(low_desc, &desc, sizeof(desc));
+
+ low_desc->entry_number = set_thread_area_entry_number;
+
+ /* 32-bit set_thread_area */
+ long ret;
+ asm volatile ("int $0x80"
+ : "=a" (ret), "+m" (*low_desc)
+ : "a" (243), "b" (low_desc)
+ : "r8", "r9", "r10", "r11");
+ memcpy(&desc, low_desc, sizeof(desc));
+ munmap(low_desc, sizeof(desc));
+
+ if (ret != 0) {
+ printf("[NOTE]\tcould not create a segment -- test won't do anything\n");
+ return 0;
+ }
+ printf("\tusing GDT slot %d\n", desc.entry_number);
+ set_thread_area_entry_number = desc.entry_number;
+
+ unsigned short gs = (unsigned short)((desc.entry_number << 3) | 0x3);
+ asm volatile ("mov %0, %%gs" : : "rm" (gs));
+ return gs;
+ }
+}
+
+void test_wrbase(unsigned short index, unsigned long base)
+{
+ unsigned short newindex;
+ unsigned long newbase;
+
+ printf("[RUN]\tGS = 0x%hx, GSBASE = 0x%lx\n", index, base);
+
+ asm volatile ("mov %0, %%gs" : : "rm" (index));
+ wrgsbase(base);
+
+ remote_base = 0;
+ ftx = 1;
+ syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0);
+ while (ftx != 0)
+ syscall(SYS_futex, &ftx, FUTEX_WAIT, 1, NULL, NULL, 0);
+
+ asm volatile ("mov %%gs, %0" : "=rm" (newindex));
+ newbase = rdgsbase();
+
+ if (newindex == index && newbase == base) {
+ printf("[OK]\tIndex and base were preserved\n");
+ } else {
+ printf("[FAIL]\tAfter switch, GS = 0x%hx and GSBASE = 0x%lx\n",
+ newindex, newbase);
+ nerrs++;
+ }
+}
+
+static void *threadproc(void *ctx)
+{
+ while (1) {
+ while (ftx == 0)
+ syscall(SYS_futex, &ftx, FUTEX_WAIT, 0, NULL, NULL, 0);
+ if (ftx == 3)
+ return NULL;
+
+ if (ftx == 1) {
+ do_remote_base();
+ } else if (ftx == 2) {
+ /*
+ * On AMD chips, this causes GSBASE != 0, GS == 0, and
+ * thread.gsbase == 0.
+ */
+
+ load_gs();
+ asm volatile ("mov %0, %%gs" : : "rm" ((unsigned short)0));
+ } else {
+ errx(1, "helper thread got bad command");
+ }
+
+ ftx = 0;
+ syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0);
+ }
+}
+
+static void set_gs_and_switch_to(unsigned long local,
+ unsigned short force_sel,
+ unsigned long remote)
+{
+ unsigned long base;
+ unsigned short sel_pre_sched, sel_post_sched;
+
+ bool hard_zero = false;
+ if (local == HARD_ZERO) {
+ hard_zero = true;
+ local = 0;
+ }
+
+ printf("[RUN]\tARCH_SET_GS(0x%lx)%s, then schedule to 0x%lx\n",
+ local, hard_zero ? " and clear gs" : "", remote);
+ if (force_sel)
+ printf("\tBefore schedule, set selector to 0x%hx\n", force_sel);
+ if (syscall(SYS_arch_prctl, ARCH_SET_GS, local) != 0)
+ err(1, "ARCH_SET_GS");
+ if (hard_zero)
+ asm volatile ("mov %0, %%gs" : : "rm" ((unsigned short)0));
+
+ if (read_base(GS) != local) {
+ nerrs++;
+ printf("[FAIL]\tGSBASE wasn't set as expected\n");
+ }
+
+ if (force_sel) {
+ asm volatile ("mov %0, %%gs" : : "rm" (force_sel));
+ sel_pre_sched = force_sel;
+ local = read_base(GS);
+
+ /*
+ * Signal delivery is quite likely to change a selector
+ * of 1, 2, or 3 back to 0 due to IRET being defective.
+ */
+ asm volatile ("mov %0, %%gs" : : "rm" (force_sel));
+ } else {
+ asm volatile ("mov %%gs, %0" : "=rm" (sel_pre_sched));
+ }
+
+ remote_base = remote;
+ ftx = 1;
+ syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0);
+ while (ftx != 0)
+ syscall(SYS_futex, &ftx, FUTEX_WAIT, 1, NULL, NULL, 0);
+
+ asm volatile ("mov %%gs, %0" : "=rm" (sel_post_sched));
+ base = read_base(GS);
+ if (base == local && sel_pre_sched == sel_post_sched) {
+ printf("[OK]\tGS/BASE remained 0x%hx/0x%lx\n",
+ sel_pre_sched, local);
+ } else if (base == local && sel_pre_sched >= 1 && sel_pre_sched <= 3 &&
+ sel_post_sched == 0) {
+ /*
+ * IRET is misdesigned and will squash selectors 1, 2, or 3
+ * to zero. Don't fail the test just because this happened.
+ */
+ printf("[OK]\tGS/BASE changed from 0x%hx/0x%lx to 0x%hx/0x%lx because IRET is defective\n",
+ sel_pre_sched, local, sel_post_sched, base);
+ } else {
+ nerrs++;
+ printf("[FAIL]\tGS/BASE changed from 0x%hx/0x%lx to 0x%hx/0x%lx\n",
+ sel_pre_sched, local, sel_post_sched, base);
+ }
+}
+
+static void test_unexpected_base(void)
+{
+ unsigned long base;
+
+ printf("[RUN]\tARCH_SET_GS(0), clear gs, then manipulate GSBASE in a different thread\n");
+ if (syscall(SYS_arch_prctl, ARCH_SET_GS, 0) != 0)
+ err(1, "ARCH_SET_GS");
+ asm volatile ("mov %0, %%gs" : : "rm" ((unsigned short)0));
+
+ ftx = 2;
+ syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0);
+ while (ftx != 0)
+ syscall(SYS_futex, &ftx, FUTEX_WAIT, 1, NULL, NULL, 0);
+
+ base = read_base(GS);
+ if (base == 0) {
+ printf("[OK]\tGSBASE remained 0\n");
+ } else {
+ nerrs++;
+ printf("[FAIL]\tGSBASE changed to 0x%lx\n", base);
+ }
+}
+
+#define USER_REGS_OFFSET(r) offsetof(struct user_regs_struct, r)
+
+static void test_ptrace_write_gs_read_base(void)
+{
+ int status;
+ pid_t child = fork();
+
+ if (child < 0)
+ err(1, "fork");
+
+ if (child == 0) {
+ printf("[RUN]\tPTRACE_POKE GS, read GSBASE back\n");
+
+ printf("[RUN]\tARCH_SET_GS to 1\n");
+ if (syscall(SYS_arch_prctl, ARCH_SET_GS, 1) != 0)
+ err(1, "ARCH_SET_GS");
+
+ if (ptrace(PTRACE_TRACEME, 0, NULL, NULL) != 0)
+ err(1, "PTRACE_TRACEME");
+
+ raise(SIGTRAP);
+ _exit(0);
+ }
+
+ wait(&status);
+
+ if (WSTOPSIG(status) == SIGTRAP) {
+ unsigned long base;
+ unsigned long gs_offset = USER_REGS_OFFSET(gs);
+ unsigned long base_offset = USER_REGS_OFFSET(gs_base);
+
+ /* Read the initial base. It should be 1. */
+ base = ptrace(PTRACE_PEEKUSER, child, base_offset, NULL);
+ if (base == 1) {
+ printf("[OK]\tGSBASE started at 1\n");
+ } else {
+ nerrs++;
+ printf("[FAIL]\tGSBASE started at 0x%lx\n", base);
+ }
+
+ printf("[RUN]\tSet GS = 0x7, read GSBASE\n");
+
+ /* Poke an LDT selector into GS. */
+ if (ptrace(PTRACE_POKEUSER, child, gs_offset, 0x7) != 0)
+ err(1, "PTRACE_POKEUSER");
+
+ /* And read the base. */
+ base = ptrace(PTRACE_PEEKUSER, child, base_offset, NULL);
+
+ if (base == 0 || base == 1) {
+ printf("[OK]\tGSBASE reads as 0x%lx with invalid GS\n", base);
+ } else {
+ nerrs++;
+ printf("[FAIL]\tGSBASE=0x%lx (should be 0 or 1)\n", base);
+ }
+ }
+
+ ptrace(PTRACE_CONT, child, NULL, NULL);
+
+ wait(&status);
+ if (!WIFEXITED(status))
+ printf("[WARN]\tChild didn't exit cleanly.\n");
+}
+
+static void test_ptrace_write_gsbase(void)
+{
+ int status;
+ pid_t child = fork();
+
+ if (child < 0)
+ err(1, "fork");
+
+ if (child == 0) {
+ printf("[RUN]\tPTRACE_POKE(), write GSBASE from ptracer\n");
+
+ *shared_scratch = load_gs();
+
+ if (ptrace(PTRACE_TRACEME, 0, NULL, NULL) != 0)
+ err(1, "PTRACE_TRACEME");
+
+ raise(SIGTRAP);
+ _exit(0);
+ }
+
+ wait(&status);
+
+ if (WSTOPSIG(status) == SIGTRAP) {
+ unsigned long gs, base;
+ unsigned long gs_offset = USER_REGS_OFFSET(gs);
+ unsigned long base_offset = USER_REGS_OFFSET(gs_base);
+
+ gs = ptrace(PTRACE_PEEKUSER, child, gs_offset, NULL);
+
+ if (gs != *shared_scratch) {
+ nerrs++;
+ printf("[FAIL]\tGS is not prepared with nonzero\n");
+ goto END;
+ }
+
+ if (ptrace(PTRACE_POKEUSER, child, base_offset, 0xFF) != 0)
+ err(1, "PTRACE_POKEUSER");
+
+ gs = ptrace(PTRACE_PEEKUSER, child, gs_offset, NULL);
+ base = ptrace(PTRACE_PEEKUSER, child, base_offset, NULL);
+
+ /*
+ * In a non-FSGSBASE system, the nonzero selector will load
+ * GSBASE (again). But what is tested here is whether the
+ * selector value is changed or not by the GSBASE write in
+ * a ptracer.
+ */
+ if (gs != *shared_scratch) {
+ nerrs++;
+ printf("[FAIL]\tGS changed to %lx\n", gs);
+
+ /*
+ * On older kernels, poking a nonzero value into the
+ * base would zero the selector. On newer kernels,
+ * this behavior has changed -- poking the base
+ * changes only the base and, if FSGSBASE is not
+ * available, this may have no effect once the tracee
+ * is resumed.
+ */
+ if (gs == 0)
+ printf("\tNote: this is expected behavior on older kernels.\n");
+ } else if (have_fsgsbase && (base != 0xFF)) {
+ nerrs++;
+ printf("[FAIL]\tGSBASE changed to %lx\n", base);
+ } else {
+ printf("[OK]\tGS remained 0x%hx", *shared_scratch);
+ if (have_fsgsbase)
+ printf(" and GSBASE changed to 0xFF");
+ printf("\n");
+ }
+ }
+
+END:
+ ptrace(PTRACE_CONT, child, NULL, NULL);
+ wait(&status);
+ if (!WIFEXITED(status))
+ printf("[WARN]\tChild didn't exit cleanly.\n");
+}
+
+int main()
+{
+ pthread_t thread;
+
+ shared_scratch = mmap(NULL, 4096, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_SHARED, -1, 0);
+
+ /* Do these tests before we have an LDT. */
+ test_ptrace_write_gs_read_base();
+
+ /* Probe FSGSBASE */
+ sethandler(SIGILL, sigill, 0);
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ rdfsbase();
+ have_fsgsbase = true;
+ printf("\tFSGSBASE instructions are enabled\n");
+ } else {
+ printf("\tFSGSBASE instructions are disabled\n");
+ }
+ clearhandler(SIGILL);
+
+ sethandler(SIGSEGV, sigsegv, 0);
+
+ check_gs_value(0);
+ check_gs_value(1);
+ check_gs_value(0x200000000);
+ check_gs_value(0);
+ check_gs_value(0x200000000);
+ check_gs_value(1);
+
+ for (int sched = 0; sched < 2; sched++) {
+ mov_0_gs(0, !!sched);
+ mov_0_gs(1, !!sched);
+ mov_0_gs(0x200000000, !!sched);
+ }
+
+ /* Set up for multithreading. */
+
+ cpu_set_t cpuset;
+ CPU_ZERO(&cpuset);
+ CPU_SET(0, &cpuset);
+ if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
+ err(1, "sched_setaffinity to CPU 0"); /* should never fail */
+
+ if (pthread_create(&thread, 0, threadproc, 0) != 0)
+ err(1, "pthread_create");
+
+ static unsigned long bases_with_hard_zero[] = {
+ 0, HARD_ZERO, 1, 0x200000000,
+ };
+
+ for (int local = 0; local < 4; local++) {
+ for (int remote = 0; remote < 4; remote++) {
+ for (unsigned short s = 0; s < 5; s++) {
+ unsigned short sel = s;
+ if (s == 4)
+ asm ("mov %%ss, %0" : "=rm" (sel));
+ set_gs_and_switch_to(
+ bases_with_hard_zero[local],
+ sel,
+ bases_with_hard_zero[remote]);
+ }
+ }
+ }
+
+ test_unexpected_base();
+
+ if (have_fsgsbase) {
+ unsigned short ss;
+
+ asm volatile ("mov %%ss, %0" : "=rm" (ss));
+
+ test_wrbase(0, 0);
+ test_wrbase(0, 1);
+ test_wrbase(0, 0x200000000);
+ test_wrbase(0, 0xffffffffffffffff);
+ test_wrbase(ss, 0);
+ test_wrbase(ss, 1);
+ test_wrbase(ss, 0x200000000);
+ test_wrbase(ss, 0xffffffffffffffff);
+ }
+
+ ftx = 3; /* Kill the thread. */
+ syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0);
+
+ if (pthread_join(thread, NULL) != 0)
+ err(1, "pthread_join");
+
+ test_ptrace_write_gsbase();
+
+ return nerrs == 0 ? 0 : 1;
+}
diff --git a/tools/testing/selftests/x86/fsgsbase_restore.c b/tools/testing/selftests/x86/fsgsbase_restore.c
new file mode 100644
index 000000000..6fffadc51
--- /dev/null
+++ b/tools/testing/selftests/x86/fsgsbase_restore.c
@@ -0,0 +1,245 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * fsgsbase_restore.c, test ptrace vs fsgsbase
+ * Copyright (c) 2020 Andy Lutomirski
+ *
+ * This test case simulates a tracer redirecting tracee execution to
+ * a function and then restoring tracee state using PTRACE_GETREGS and
+ * PTRACE_SETREGS. This is similar to what gdb does when doing
+ * 'p func()'. The catch is that this test has the called function
+ * modify a segment register. This makes sure that ptrace correctly
+ * restores segment state when using PTRACE_SETREGS.
+ *
+ * This is not part of fsgsbase.c, because that test is 64-bit only.
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <err.h>
+#include <sys/user.h>
+#include <asm/prctl.h>
+#include <sys/prctl.h>
+#include <asm/ldt.h>
+#include <sys/mman.h>
+#include <stddef.h>
+#include <sys/ptrace.h>
+#include <sys/wait.h>
+#include <stdint.h>
+
+#define EXPECTED_VALUE 0x1337f00d
+
+#ifdef __x86_64__
+# define SEG "%gs"
+#else
+# define SEG "%fs"
+#endif
+
+static unsigned int dereference_seg_base(void)
+{
+ int ret;
+ asm volatile ("mov %" SEG ":(0), %0" : "=rm" (ret));
+ return ret;
+}
+
+static void init_seg(void)
+{
+ unsigned int *target = mmap(
+ NULL, sizeof(unsigned int),
+ PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_32BIT, -1, 0);
+ if (target == MAP_FAILED)
+ err(1, "mmap");
+
+ *target = EXPECTED_VALUE;
+
+ printf("\tsegment base address = 0x%lx\n", (unsigned long)target);
+
+ struct user_desc desc = {
+ .entry_number = 0,
+ .base_addr = (unsigned int)(uintptr_t)target,
+ .limit = sizeof(unsigned int) - 1,
+ .seg_32bit = 1,
+ .contents = 0, /* Data, grow-up */
+ .read_exec_only = 0,
+ .limit_in_pages = 0,
+ .seg_not_present = 0,
+ .useable = 0
+ };
+ if (syscall(SYS_modify_ldt, 1, &desc, sizeof(desc)) == 0) {
+ printf("\tusing LDT slot 0\n");
+ asm volatile ("mov %0, %" SEG :: "rm" ((unsigned short)0x7));
+ } else {
+ /* No modify_ldt for us (configured out, perhaps) */
+
+ struct user_desc *low_desc = mmap(
+ NULL, sizeof(desc),
+ PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_32BIT, -1, 0);
+ memcpy(low_desc, &desc, sizeof(desc));
+
+ low_desc->entry_number = -1;
+
+ /* 32-bit set_thread_area */
+ long ret;
+ asm volatile ("int $0x80"
+ : "=a" (ret), "+m" (*low_desc)
+ : "a" (243), "b" (low_desc)
+#ifdef __x86_64__
+ : "r8", "r9", "r10", "r11"
+#endif
+ );
+ memcpy(&desc, low_desc, sizeof(desc));
+ munmap(low_desc, sizeof(desc));
+
+ if (ret != 0) {
+ printf("[NOTE]\tcould not create a segment -- can't test anything\n");
+ exit(0);
+ }
+ printf("\tusing GDT slot %d\n", desc.entry_number);
+
+ unsigned short sel = (unsigned short)((desc.entry_number << 3) | 0x3);
+ asm volatile ("mov %0, %" SEG :: "rm" (sel));
+ }
+}
+
+static void tracee_zap_segment(void)
+{
+ /*
+ * The tracer will redirect execution here. This is meant to
+ * work like gdb's 'p func()' feature. The tricky bit is that
+ * we modify a segment register in order to make sure that ptrace
+ * can correctly restore segment registers.
+ */
+ printf("\tTracee: in tracee_zap_segment()\n");
+
+ /*
+ * Write a nonzero selector with base zero to the segment register.
+ * Using a null selector would defeat the test on AMD pre-Zen2
+ * CPUs, as such CPUs don't clear the base when loading a null
+ * selector.
+ */
+ unsigned short sel;
+ asm volatile ("mov %%ss, %0\n\t"
+ "mov %0, %" SEG
+ : "=rm" (sel));
+
+ pid_t pid = getpid(), tid = syscall(SYS_gettid);
+
+ printf("\tTracee is going back to sleep\n");
+ syscall(SYS_tgkill, pid, tid, SIGSTOP);
+
+ /* Should not get here. */
+ while (true) {
+ printf("[FAIL]\tTracee hit unreachable code\n");
+ pause();
+ }
+}
+
+int main()
+{
+ printf("\tSetting up a segment\n");
+ init_seg();
+
+ unsigned int val = dereference_seg_base();
+ if (val != EXPECTED_VALUE) {
+ printf("[FAIL]\tseg[0] == %x; should be %x\n", val, EXPECTED_VALUE);
+ return 1;
+ }
+ printf("[OK]\tThe segment points to the right place.\n");
+
+ pid_t chld = fork();
+ if (chld < 0)
+ err(1, "fork");
+
+ if (chld == 0) {
+ prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0, 0);
+
+ if (ptrace(PTRACE_TRACEME, 0, 0, 0) != 0)
+ err(1, "PTRACE_TRACEME");
+
+ pid_t pid = getpid(), tid = syscall(SYS_gettid);
+
+ printf("\tTracee will take a nap until signaled\n");
+ syscall(SYS_tgkill, pid, tid, SIGSTOP);
+
+ printf("\tTracee was resumed. Will re-check segment.\n");
+
+ val = dereference_seg_base();
+ if (val != EXPECTED_VALUE) {
+ printf("[FAIL]\tseg[0] == %x; should be %x\n", val, EXPECTED_VALUE);
+ exit(1);
+ }
+
+ printf("[OK]\tThe segment points to the right place.\n");
+ exit(0);
+ }
+
+ int status;
+
+ /* Wait for SIGSTOP. */
+ if (waitpid(chld, &status, 0) != chld || !WIFSTOPPED(status))
+ err(1, "waitpid");
+
+ struct user_regs_struct regs;
+
+ if (ptrace(PTRACE_GETREGS, chld, NULL, &regs) != 0)
+ err(1, "PTRACE_GETREGS");
+
+#ifdef __x86_64__
+ printf("\tChild GS=0x%lx, GSBASE=0x%lx\n", (unsigned long)regs.gs, (unsigned long)regs.gs_base);
+#else
+ printf("\tChild FS=0x%lx\n", (unsigned long)regs.xfs);
+#endif
+
+ struct user_regs_struct regs2 = regs;
+#ifdef __x86_64__
+ regs2.rip = (unsigned long)tracee_zap_segment;
+ regs2.rsp -= 128; /* Don't clobber the redzone. */
+#else
+ regs2.eip = (unsigned long)tracee_zap_segment;
+#endif
+
+ printf("\tTracer: redirecting tracee to tracee_zap_segment()\n");
+ if (ptrace(PTRACE_SETREGS, chld, NULL, &regs2) != 0)
+ err(1, "PTRACE_GETREGS");
+ if (ptrace(PTRACE_CONT, chld, NULL, NULL) != 0)
+ err(1, "PTRACE_GETREGS");
+
+ /* Wait for SIGSTOP. */
+ if (waitpid(chld, &status, 0) != chld || !WIFSTOPPED(status))
+ err(1, "waitpid");
+
+ printf("\tTracer: restoring tracee state\n");
+ if (ptrace(PTRACE_SETREGS, chld, NULL, &regs) != 0)
+ err(1, "PTRACE_GETREGS");
+ if (ptrace(PTRACE_DETACH, chld, NULL, NULL) != 0)
+ err(1, "PTRACE_GETREGS");
+
+ /* Wait for SIGSTOP. */
+ if (waitpid(chld, &status, 0) != chld)
+ err(1, "waitpid");
+
+ if (WIFSIGNALED(status)) {
+ printf("[FAIL]\tTracee crashed\n");
+ return 1;
+ }
+
+ if (!WIFEXITED(status)) {
+ printf("[FAIL]\tTracee stopped for an unexpected reason: %d\n", status);
+ return 1;
+ }
+
+ int exitcode = WEXITSTATUS(status);
+ if (exitcode != 0) {
+ printf("[FAIL]\tTracee reported failure\n");
+ return 1;
+ }
+
+ printf("[OK]\tAll is well.\n");
+ return 0;
+}
diff --git a/tools/testing/selftests/x86/helpers.h b/tools/testing/selftests/x86/helpers.h
new file mode 100644
index 000000000..4ef42c455
--- /dev/null
+++ b/tools/testing/selftests/x86/helpers.h
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#ifndef __SELFTESTS_X86_HELPERS_H
+#define __SELFTESTS_X86_HELPERS_H
+
+#include <asm/processor-flags.h>
+
+static inline unsigned long get_eflags(void)
+{
+#ifdef __x86_64__
+ return __builtin_ia32_readeflags_u64();
+#else
+ return __builtin_ia32_readeflags_u32();
+#endif
+}
+
+static inline void set_eflags(unsigned long eflags)
+{
+#ifdef __x86_64__
+ __builtin_ia32_writeeflags_u64(eflags);
+#else
+ __builtin_ia32_writeeflags_u32(eflags);
+#endif
+}
+
+#endif /* __SELFTESTS_X86_HELPERS_H */
diff --git a/tools/testing/selftests/x86/ioperm.c b/tools/testing/selftests/x86/ioperm.c
new file mode 100644
index 000000000..57ec5e99e
--- /dev/null
+++ b/tools/testing/selftests/x86/ioperm.c
@@ -0,0 +1,185 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ioperm.c - Test case for ioperm(2)
+ * Copyright (c) 2015 Andrew Lutomirski
+ */
+
+#define _GNU_SOURCE
+#include <err.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <signal.h>
+#include <setjmp.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdbool.h>
+#include <sched.h>
+#include <sys/io.h>
+
+static int nerrs = 0;
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+
+}
+
+static void clearhandler(int sig)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_handler = SIG_DFL;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static jmp_buf jmpbuf;
+
+static void sigsegv(int sig, siginfo_t *si, void *ctx_void)
+{
+ siglongjmp(jmpbuf, 1);
+}
+
+static bool try_outb(unsigned short port)
+{
+ sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
+ if (sigsetjmp(jmpbuf, 1) != 0) {
+ return false;
+ } else {
+ asm volatile ("outb %%al, %w[port]"
+ : : [port] "Nd" (port), "a" (0));
+ return true;
+ }
+ clearhandler(SIGSEGV);
+}
+
+static void expect_ok(unsigned short port)
+{
+ if (!try_outb(port)) {
+ printf("[FAIL]\toutb to 0x%02hx failed\n", port);
+ exit(1);
+ }
+
+ printf("[OK]\toutb to 0x%02hx worked\n", port);
+}
+
+static void expect_gp(unsigned short port)
+{
+ if (try_outb(port)) {
+ printf("[FAIL]\toutb to 0x%02hx worked\n", port);
+ exit(1);
+ }
+
+ printf("[OK]\toutb to 0x%02hx failed\n", port);
+}
+
+int main(void)
+{
+ cpu_set_t cpuset;
+ CPU_ZERO(&cpuset);
+ CPU_SET(0, &cpuset);
+ if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
+ err(1, "sched_setaffinity to CPU 0");
+
+ expect_gp(0x80);
+ expect_gp(0xed);
+
+ /*
+ * Probe for ioperm support. Note that clearing ioperm bits
+ * works even as nonroot.
+ */
+ printf("[RUN]\tenable 0x80\n");
+ if (ioperm(0x80, 1, 1) != 0) {
+ printf("[OK]\tioperm(0x80, 1, 1) failed (%d) -- try running as root\n",
+ errno);
+ return 0;
+ }
+ expect_ok(0x80);
+ expect_gp(0xed);
+
+ printf("[RUN]\tdisable 0x80\n");
+ if (ioperm(0x80, 1, 0) != 0) {
+ printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
+ return 1;
+ }
+ expect_gp(0x80);
+ expect_gp(0xed);
+
+ /* Make sure that fork() preserves ioperm. */
+ if (ioperm(0x80, 1, 1) != 0) {
+ printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
+ return 1;
+ }
+
+ pid_t child = fork();
+ if (child == -1)
+ err(1, "fork");
+
+ if (child == 0) {
+ printf("[RUN]\tchild: check that we inherited permissions\n");
+ expect_ok(0x80);
+ expect_gp(0xed);
+ printf("[RUN]\tchild: Extend permissions to 0x81\n");
+ if (ioperm(0x81, 1, 1) != 0) {
+ printf("[FAIL]\tioperm(0x81, 1, 1) failed (%d)", errno);
+ return 1;
+ }
+ printf("[RUN]\tchild: Drop permissions to 0x80\n");
+ if (ioperm(0x80, 1, 0) != 0) {
+ printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
+ return 1;
+ }
+ expect_gp(0x80);
+ return 0;
+ } else {
+ int status;
+ if (waitpid(child, &status, 0) != child ||
+ !WIFEXITED(status)) {
+ printf("[FAIL]\tChild died\n");
+ nerrs++;
+ } else if (WEXITSTATUS(status) != 0) {
+ printf("[FAIL]\tChild failed\n");
+ nerrs++;
+ } else {
+ printf("[OK]\tChild succeeded\n");
+ }
+ }
+
+ /* Verify that the child dropping 0x80 did not affect the parent */
+ printf("\tVerify that unsharing the bitmap worked\n");
+ expect_ok(0x80);
+
+ /* Test the capability checks. */
+ printf("\tDrop privileges\n");
+ if (setresuid(1, 1, 1) != 0) {
+ printf("[WARN]\tDropping privileges failed\n");
+ return 0;
+ }
+
+ printf("[RUN]\tdisable 0x80\n");
+ if (ioperm(0x80, 1, 0) != 0) {
+ printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
+ return 1;
+ }
+ printf("[OK]\tit worked\n");
+
+ printf("[RUN]\tenable 0x80 again\n");
+ if (ioperm(0x80, 1, 1) == 0) {
+ printf("[FAIL]\tit succeeded but should have failed.\n");
+ return 1;
+ }
+ printf("[OK]\tit failed\n");
+ return 0;
+}
diff --git a/tools/testing/selftests/x86/iopl.c b/tools/testing/selftests/x86/iopl.c
new file mode 100644
index 000000000..7e3e09c1a
--- /dev/null
+++ b/tools/testing/selftests/x86/iopl.c
@@ -0,0 +1,281 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * iopl.c - Test case for a Linux on Xen 64-bit bug
+ * Copyright (c) 2015 Andrew Lutomirski
+ */
+
+#define _GNU_SOURCE
+#include <err.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <signal.h>
+#include <setjmp.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdbool.h>
+#include <sched.h>
+#include <sys/io.h>
+
+static int nerrs = 0;
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+
+}
+
+static void clearhandler(int sig)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_handler = SIG_DFL;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static jmp_buf jmpbuf;
+
+static void sigsegv(int sig, siginfo_t *si, void *ctx_void)
+{
+ siglongjmp(jmpbuf, 1);
+}
+
+static bool try_outb(unsigned short port)
+{
+ sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
+ if (sigsetjmp(jmpbuf, 1) != 0) {
+ return false;
+ } else {
+ asm volatile ("outb %%al, %w[port]"
+ : : [port] "Nd" (port), "a" (0));
+ return true;
+ }
+ clearhandler(SIGSEGV);
+}
+
+static void expect_ok_outb(unsigned short port)
+{
+ if (!try_outb(port)) {
+ printf("[FAIL]\toutb to 0x%02hx failed\n", port);
+ exit(1);
+ }
+
+ printf("[OK]\toutb to 0x%02hx worked\n", port);
+}
+
+static void expect_gp_outb(unsigned short port)
+{
+ if (try_outb(port)) {
+ printf("[FAIL]\toutb to 0x%02hx worked\n", port);
+ nerrs++;
+ }
+
+ printf("[OK]\toutb to 0x%02hx failed\n", port);
+}
+
+#define RET_FAULTED 0
+#define RET_FAIL 1
+#define RET_EMUL 2
+
+static int try_cli(void)
+{
+ unsigned long flags;
+
+ sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
+ if (sigsetjmp(jmpbuf, 1) != 0) {
+ return RET_FAULTED;
+ } else {
+ asm volatile("cli; pushf; pop %[flags]"
+ : [flags] "=rm" (flags));
+
+ /* X86_FLAGS_IF */
+ if (!(flags & (1 << 9)))
+ return RET_FAIL;
+ else
+ return RET_EMUL;
+ }
+ clearhandler(SIGSEGV);
+}
+
+static int try_sti(bool irqs_off)
+{
+ unsigned long flags;
+
+ sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
+ if (sigsetjmp(jmpbuf, 1) != 0) {
+ return RET_FAULTED;
+ } else {
+ asm volatile("sti; pushf; pop %[flags]"
+ : [flags] "=rm" (flags));
+
+ /* X86_FLAGS_IF */
+ if (irqs_off && (flags & (1 << 9)))
+ return RET_FAIL;
+ else
+ return RET_EMUL;
+ }
+ clearhandler(SIGSEGV);
+}
+
+static void expect_gp_sti(bool irqs_off)
+{
+ int ret = try_sti(irqs_off);
+
+ switch (ret) {
+ case RET_FAULTED:
+ printf("[OK]\tSTI faulted\n");
+ break;
+ case RET_EMUL:
+ printf("[OK]\tSTI NOPped\n");
+ break;
+ default:
+ printf("[FAIL]\tSTI worked\n");
+ nerrs++;
+ }
+}
+
+/*
+ * Returns whether it managed to disable interrupts.
+ */
+static bool test_cli(void)
+{
+ int ret = try_cli();
+
+ switch (ret) {
+ case RET_FAULTED:
+ printf("[OK]\tCLI faulted\n");
+ break;
+ case RET_EMUL:
+ printf("[OK]\tCLI NOPped\n");
+ break;
+ default:
+ printf("[FAIL]\tCLI worked\n");
+ nerrs++;
+ return true;
+ }
+
+ return false;
+}
+
+int main(void)
+{
+ cpu_set_t cpuset;
+
+ CPU_ZERO(&cpuset);
+ CPU_SET(0, &cpuset);
+ if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
+ err(1, "sched_setaffinity to CPU 0");
+
+ /* Probe for iopl support. Note that iopl(0) works even as nonroot. */
+ switch(iopl(3)) {
+ case 0:
+ break;
+ case -ENOSYS:
+ printf("[OK]\tiopl() nor supported\n");
+ return 0;
+ default:
+ printf("[OK]\tiopl(3) failed (%d) -- try running as root\n",
+ errno);
+ return 0;
+ }
+
+ /* Make sure that CLI/STI are blocked even with IOPL level 3 */
+ expect_gp_sti(test_cli());
+ expect_ok_outb(0x80);
+
+ /* Establish an I/O bitmap to test the restore */
+ if (ioperm(0x80, 1, 1) != 0)
+ err(1, "ioperm(0x80, 1, 1) failed\n");
+
+ /* Restore our original state prior to starting the fork test. */
+ if (iopl(0) != 0)
+ err(1, "iopl(0)");
+
+ /*
+ * Verify that IOPL emulation is disabled and the I/O bitmap still
+ * works.
+ */
+ expect_ok_outb(0x80);
+ expect_gp_outb(0xed);
+ /* Drop the I/O bitmap */
+ if (ioperm(0x80, 1, 0) != 0)
+ err(1, "ioperm(0x80, 1, 0) failed\n");
+
+ pid_t child = fork();
+ if (child == -1)
+ err(1, "fork");
+
+ if (child == 0) {
+ printf("\tchild: set IOPL to 3\n");
+ if (iopl(3) != 0)
+ err(1, "iopl");
+
+ printf("[RUN]\tchild: write to 0x80\n");
+ asm volatile ("outb %%al, $0x80" : : "a" (0));
+
+ return 0;
+ } else {
+ int status;
+ if (waitpid(child, &status, 0) != child ||
+ !WIFEXITED(status)) {
+ printf("[FAIL]\tChild died\n");
+ nerrs++;
+ } else if (WEXITSTATUS(status) != 0) {
+ printf("[FAIL]\tChild failed\n");
+ nerrs++;
+ } else {
+ printf("[OK]\tChild succeeded\n");
+ }
+ }
+
+ printf("[RUN]\tparent: write to 0x80 (should fail)\n");
+
+ expect_gp_outb(0x80);
+ expect_gp_sti(test_cli());
+
+ /* Test the capability checks. */
+ printf("\tiopl(3)\n");
+ if (iopl(3) != 0)
+ err(1, "iopl(3)");
+
+ printf("\tDrop privileges\n");
+ if (setresuid(1, 1, 1) != 0) {
+ printf("[WARN]\tDropping privileges failed\n");
+ goto done;
+ }
+
+ printf("[RUN]\tiopl(3) unprivileged but with IOPL==3\n");
+ if (iopl(3) != 0) {
+ printf("[FAIL]\tiopl(3) should work if iopl is already 3 even if unprivileged\n");
+ nerrs++;
+ }
+
+ printf("[RUN]\tiopl(0) unprivileged\n");
+ if (iopl(0) != 0) {
+ printf("[FAIL]\tiopl(0) should work if iopl is already 3 even if unprivileged\n");
+ nerrs++;
+ }
+
+ printf("[RUN]\tiopl(3) unprivileged\n");
+ if (iopl(3) == 0) {
+ printf("[FAIL]\tiopl(3) should fail if when unprivileged if iopl==0\n");
+ nerrs++;
+ } else {
+ printf("[OK]\tFailed as expected\n");
+ }
+
+done:
+ return nerrs ? 1 : 0;
+}
diff --git a/tools/testing/selftests/x86/ldt_gdt.c b/tools/testing/selftests/x86/ldt_gdt.c
new file mode 100644
index 000000000..3a29346e1
--- /dev/null
+++ b/tools/testing/selftests/x86/ldt_gdt.c
@@ -0,0 +1,927 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ldt_gdt.c - Test cases for LDT and GDT access
+ * Copyright (c) 2015 Andrew Lutomirski
+ */
+
+#define _GNU_SOURCE
+#include <err.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <signal.h>
+#include <setjmp.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <asm/ldt.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdbool.h>
+#include <pthread.h>
+#include <sched.h>
+#include <linux/futex.h>
+#include <sys/mman.h>
+#include <asm/prctl.h>
+#include <sys/prctl.h>
+
+#define AR_ACCESSED (1<<8)
+
+#define AR_TYPE_RODATA (0 * (1<<9))
+#define AR_TYPE_RWDATA (1 * (1<<9))
+#define AR_TYPE_RODATA_EXPDOWN (2 * (1<<9))
+#define AR_TYPE_RWDATA_EXPDOWN (3 * (1<<9))
+#define AR_TYPE_XOCODE (4 * (1<<9))
+#define AR_TYPE_XRCODE (5 * (1<<9))
+#define AR_TYPE_XOCODE_CONF (6 * (1<<9))
+#define AR_TYPE_XRCODE_CONF (7 * (1<<9))
+
+#define AR_DPL3 (3 * (1<<13))
+
+#define AR_S (1 << 12)
+#define AR_P (1 << 15)
+#define AR_AVL (1 << 20)
+#define AR_L (1 << 21)
+#define AR_DB (1 << 22)
+#define AR_G (1 << 23)
+
+#ifdef __x86_64__
+# define INT80_CLOBBERS "r8", "r9", "r10", "r11"
+#else
+# define INT80_CLOBBERS
+#endif
+
+static int nerrs;
+
+/* Points to an array of 1024 ints, each holding its own index. */
+static const unsigned int *counter_page;
+static struct user_desc *low_user_desc;
+static struct user_desc *low_user_desc_clear; /* Use to delete GDT entry */
+static int gdt_entry_num;
+
+static void check_invalid_segment(uint16_t index, int ldt)
+{
+ uint32_t has_limit = 0, has_ar = 0, limit, ar;
+ uint32_t selector = (index << 3) | (ldt << 2) | 3;
+
+ asm ("lsl %[selector], %[limit]\n\t"
+ "jnz 1f\n\t"
+ "movl $1, %[has_limit]\n\t"
+ "1:"
+ : [limit] "=r" (limit), [has_limit] "+rm" (has_limit)
+ : [selector] "r" (selector));
+ asm ("larl %[selector], %[ar]\n\t"
+ "jnz 1f\n\t"
+ "movl $1, %[has_ar]\n\t"
+ "1:"
+ : [ar] "=r" (ar), [has_ar] "+rm" (has_ar)
+ : [selector] "r" (selector));
+
+ if (has_limit || has_ar) {
+ printf("[FAIL]\t%s entry %hu is valid but should be invalid\n",
+ (ldt ? "LDT" : "GDT"), index);
+ nerrs++;
+ } else {
+ printf("[OK]\t%s entry %hu is invalid\n",
+ (ldt ? "LDT" : "GDT"), index);
+ }
+}
+
+static void check_valid_segment(uint16_t index, int ldt,
+ uint32_t expected_ar, uint32_t expected_limit,
+ bool verbose)
+{
+ uint32_t has_limit = 0, has_ar = 0, limit, ar;
+ uint32_t selector = (index << 3) | (ldt << 2) | 3;
+
+ asm ("lsl %[selector], %[limit]\n\t"
+ "jnz 1f\n\t"
+ "movl $1, %[has_limit]\n\t"
+ "1:"
+ : [limit] "=r" (limit), [has_limit] "+rm" (has_limit)
+ : [selector] "r" (selector));
+ asm ("larl %[selector], %[ar]\n\t"
+ "jnz 1f\n\t"
+ "movl $1, %[has_ar]\n\t"
+ "1:"
+ : [ar] "=r" (ar), [has_ar] "+rm" (has_ar)
+ : [selector] "r" (selector));
+
+ if (!has_limit || !has_ar) {
+ printf("[FAIL]\t%s entry %hu is invalid but should be valid\n",
+ (ldt ? "LDT" : "GDT"), index);
+ nerrs++;
+ return;
+ }
+
+ /* The SDM says "bits 19:16 are undefined". Thanks. */
+ ar &= ~0xF0000;
+
+ /*
+ * NB: Different Linux versions do different things with the
+ * accessed bit in set_thread_area().
+ */
+ if (ar != expected_ar && ar != (expected_ar | AR_ACCESSED)) {
+ printf("[FAIL]\t%s entry %hu has AR 0x%08X but expected 0x%08X\n",
+ (ldt ? "LDT" : "GDT"), index, ar, expected_ar);
+ nerrs++;
+ } else if (limit != expected_limit) {
+ printf("[FAIL]\t%s entry %hu has limit 0x%08X but expected 0x%08X\n",
+ (ldt ? "LDT" : "GDT"), index, limit, expected_limit);
+ nerrs++;
+ } else if (verbose) {
+ printf("[OK]\t%s entry %hu has AR 0x%08X and limit 0x%08X\n",
+ (ldt ? "LDT" : "GDT"), index, ar, limit);
+ }
+}
+
+static bool install_valid_mode(const struct user_desc *d, uint32_t ar,
+ bool oldmode, bool ldt)
+{
+ struct user_desc desc = *d;
+ int ret;
+
+ if (!ldt) {
+#ifndef __i386__
+ /* No point testing set_thread_area in a 64-bit build */
+ return false;
+#endif
+ if (!gdt_entry_num)
+ return false;
+ desc.entry_number = gdt_entry_num;
+
+ ret = syscall(SYS_set_thread_area, &desc);
+ } else {
+ ret = syscall(SYS_modify_ldt, oldmode ? 1 : 0x11,
+ &desc, sizeof(desc));
+
+ if (ret < -1)
+ errno = -ret;
+
+ if (ret != 0 && errno == ENOSYS) {
+ printf("[OK]\tmodify_ldt returned -ENOSYS\n");
+ return false;
+ }
+ }
+
+ if (ret == 0) {
+ uint32_t limit = desc.limit;
+ if (desc.limit_in_pages)
+ limit = (limit << 12) + 4095;
+ check_valid_segment(desc.entry_number, ldt, ar, limit, true);
+ return true;
+ } else {
+ if (desc.seg_32bit) {
+ printf("[FAIL]\tUnexpected %s failure %d\n",
+ ldt ? "modify_ldt" : "set_thread_area",
+ errno);
+ nerrs++;
+ return false;
+ } else {
+ printf("[OK]\t%s rejected 16 bit segment\n",
+ ldt ? "modify_ldt" : "set_thread_area");
+ return false;
+ }
+ }
+}
+
+static bool install_valid(const struct user_desc *desc, uint32_t ar)
+{
+ bool ret = install_valid_mode(desc, ar, false, true);
+
+ if (desc->contents <= 1 && desc->seg_32bit &&
+ !desc->seg_not_present) {
+ /* Should work in the GDT, too. */
+ install_valid_mode(desc, ar, false, false);
+ }
+
+ return ret;
+}
+
+static void install_invalid(const struct user_desc *desc, bool oldmode)
+{
+ int ret = syscall(SYS_modify_ldt, oldmode ? 1 : 0x11,
+ desc, sizeof(*desc));
+ if (ret < -1)
+ errno = -ret;
+ if (ret == 0) {
+ check_invalid_segment(desc->entry_number, 1);
+ } else if (errno == ENOSYS) {
+ printf("[OK]\tmodify_ldt returned -ENOSYS\n");
+ } else {
+ if (desc->seg_32bit) {
+ printf("[FAIL]\tUnexpected modify_ldt failure %d\n",
+ errno);
+ nerrs++;
+ } else {
+ printf("[OK]\tmodify_ldt rejected 16 bit segment\n");
+ }
+ }
+}
+
+static int safe_modify_ldt(int func, struct user_desc *ptr,
+ unsigned long bytecount)
+{
+ int ret = syscall(SYS_modify_ldt, 0x11, ptr, bytecount);
+ if (ret < -1)
+ errno = -ret;
+ return ret;
+}
+
+static void fail_install(struct user_desc *desc)
+{
+ if (safe_modify_ldt(0x11, desc, sizeof(*desc)) == 0) {
+ printf("[FAIL]\tmodify_ldt accepted a bad descriptor\n");
+ nerrs++;
+ } else if (errno == ENOSYS) {
+ printf("[OK]\tmodify_ldt returned -ENOSYS\n");
+ } else {
+ printf("[OK]\tmodify_ldt failure %d\n", errno);
+ }
+}
+
+static void do_simple_tests(void)
+{
+ struct user_desc desc = {
+ .entry_number = 0,
+ .base_addr = 0,
+ .limit = 10,
+ .seg_32bit = 1,
+ .contents = 2, /* Code, not conforming */
+ .read_exec_only = 0,
+ .limit_in_pages = 0,
+ .seg_not_present = 0,
+ .useable = 0
+ };
+ install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE | AR_S | AR_P | AR_DB);
+
+ desc.limit_in_pages = 1;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE |
+ AR_S | AR_P | AR_DB | AR_G);
+
+ check_invalid_segment(1, 1);
+
+ desc.entry_number = 2;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE |
+ AR_S | AR_P | AR_DB | AR_G);
+
+ check_invalid_segment(1, 1);
+
+ desc.base_addr = 0xf0000000;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE |
+ AR_S | AR_P | AR_DB | AR_G);
+
+ desc.useable = 1;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE |
+ AR_S | AR_P | AR_DB | AR_G | AR_AVL);
+
+ desc.seg_not_present = 1;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE |
+ AR_S | AR_DB | AR_G | AR_AVL);
+
+ desc.seg_32bit = 0;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE |
+ AR_S | AR_G | AR_AVL);
+
+ desc.seg_32bit = 1;
+ desc.contents = 0;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA |
+ AR_S | AR_DB | AR_G | AR_AVL);
+
+ desc.read_exec_only = 1;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA |
+ AR_S | AR_DB | AR_G | AR_AVL);
+
+ desc.contents = 1;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA_EXPDOWN |
+ AR_S | AR_DB | AR_G | AR_AVL);
+
+ desc.read_exec_only = 0;
+ desc.limit_in_pages = 0;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA_EXPDOWN |
+ AR_S | AR_DB | AR_AVL);
+
+ desc.contents = 3;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE_CONF |
+ AR_S | AR_DB | AR_AVL);
+
+ desc.read_exec_only = 1;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_XOCODE_CONF |
+ AR_S | AR_DB | AR_AVL);
+
+ desc.read_exec_only = 0;
+ desc.contents = 2;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE |
+ AR_S | AR_DB | AR_AVL);
+
+ desc.read_exec_only = 1;
+
+#ifdef __x86_64__
+ desc.lm = 1;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_XOCODE |
+ AR_S | AR_DB | AR_AVL);
+ desc.lm = 0;
+#endif
+
+ bool entry1_okay = install_valid(&desc, AR_DPL3 | AR_TYPE_XOCODE |
+ AR_S | AR_DB | AR_AVL);
+
+ if (entry1_okay) {
+ printf("[RUN]\tTest fork\n");
+ pid_t child = fork();
+ if (child == 0) {
+ nerrs = 0;
+ check_valid_segment(desc.entry_number, 1,
+ AR_DPL3 | AR_TYPE_XOCODE |
+ AR_S | AR_DB | AR_AVL, desc.limit,
+ true);
+ check_invalid_segment(1, 1);
+ exit(nerrs ? 1 : 0);
+ } else {
+ int status;
+ if (waitpid(child, &status, 0) != child ||
+ !WIFEXITED(status)) {
+ printf("[FAIL]\tChild died\n");
+ nerrs++;
+ } else if (WEXITSTATUS(status) != 0) {
+ printf("[FAIL]\tChild failed\n");
+ nerrs++;
+ } else {
+ printf("[OK]\tChild succeeded\n");
+ }
+ }
+
+ printf("[RUN]\tTest size\n");
+ int i;
+ for (i = 0; i < 8192; i++) {
+ desc.entry_number = i;
+ desc.limit = i;
+ if (safe_modify_ldt(0x11, &desc, sizeof(desc)) != 0) {
+ printf("[FAIL]\tFailed to install entry %d\n", i);
+ nerrs++;
+ break;
+ }
+ }
+ for (int j = 0; j < i; j++) {
+ check_valid_segment(j, 1, AR_DPL3 | AR_TYPE_XOCODE |
+ AR_S | AR_DB | AR_AVL, j, false);
+ }
+ printf("[DONE]\tSize test\n");
+ } else {
+ printf("[SKIP]\tSkipping fork and size tests because we have no LDT\n");
+ }
+
+ /* Test entry_number too high. */
+ desc.entry_number = 8192;
+ fail_install(&desc);
+
+ /* Test deletion and actions mistakeable for deletion. */
+ memset(&desc, 0, sizeof(desc));
+ install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S | AR_P);
+
+ desc.seg_not_present = 1;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S);
+
+ desc.seg_not_present = 0;
+ desc.read_exec_only = 1;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA | AR_S | AR_P);
+
+ desc.read_exec_only = 0;
+ desc.seg_not_present = 1;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S);
+
+ desc.read_exec_only = 1;
+ desc.limit = 1;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA | AR_S);
+
+ desc.limit = 0;
+ desc.base_addr = 1;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA | AR_S);
+
+ desc.base_addr = 0;
+ install_invalid(&desc, false);
+
+ desc.seg_not_present = 0;
+ desc.seg_32bit = 1;
+ desc.read_exec_only = 0;
+ desc.limit = 0xfffff;
+
+ install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S | AR_P | AR_DB);
+
+ desc.limit_in_pages = 1;
+
+ install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S | AR_P | AR_DB | AR_G);
+ desc.read_exec_only = 1;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA | AR_S | AR_P | AR_DB | AR_G);
+ desc.contents = 1;
+ desc.read_exec_only = 0;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA_EXPDOWN | AR_S | AR_P | AR_DB | AR_G);
+ desc.read_exec_only = 1;
+ install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA_EXPDOWN | AR_S | AR_P | AR_DB | AR_G);
+
+ desc.limit = 0;
+ install_invalid(&desc, true);
+}
+
+/*
+ * 0: thread is idle
+ * 1: thread armed
+ * 2: thread should clear LDT entry 0
+ * 3: thread should exit
+ */
+static volatile unsigned int ftx;
+
+static void *threadproc(void *ctx)
+{
+ cpu_set_t cpuset;
+ CPU_ZERO(&cpuset);
+ CPU_SET(1, &cpuset);
+ if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
+ err(1, "sched_setaffinity to CPU 1"); /* should never fail */
+
+ while (1) {
+ syscall(SYS_futex, &ftx, FUTEX_WAIT, 0, NULL, NULL, 0);
+ while (ftx != 2) {
+ if (ftx >= 3)
+ return NULL;
+ }
+
+ /* clear LDT entry 0 */
+ const struct user_desc desc = {};
+ if (syscall(SYS_modify_ldt, 1, &desc, sizeof(desc)) != 0)
+ err(1, "modify_ldt");
+
+ /* If ftx == 2, set it to zero. If ftx == 100, quit. */
+ unsigned int x = -2;
+ asm volatile ("lock xaddl %[x], %[ftx]" :
+ [x] "+r" (x), [ftx] "+m" (ftx));
+ if (x != 2)
+ return NULL;
+ }
+}
+
+#ifdef __i386__
+
+#ifndef SA_RESTORE
+#define SA_RESTORER 0x04000000
+#endif
+
+/*
+ * The UAPI header calls this 'struct sigaction', which conflicts with
+ * glibc. Sigh.
+ */
+struct fake_ksigaction {
+ void *handler; /* the real type is nasty */
+ unsigned long sa_flags;
+ void (*sa_restorer)(void);
+ unsigned char sigset[8];
+};
+
+static void fix_sa_restorer(int sig)
+{
+ struct fake_ksigaction ksa;
+
+ if (syscall(SYS_rt_sigaction, sig, NULL, &ksa, 8) == 0) {
+ /*
+ * glibc has a nasty bug: it sometimes writes garbage to
+ * sa_restorer. This interacts quite badly with anything
+ * that fiddles with SS because it can trigger legacy
+ * stack switching. Patch it up. See:
+ *
+ * https://sourceware.org/bugzilla/show_bug.cgi?id=21269
+ */
+ if (!(ksa.sa_flags & SA_RESTORER) && ksa.sa_restorer) {
+ ksa.sa_restorer = NULL;
+ if (syscall(SYS_rt_sigaction, sig, &ksa, NULL,
+ sizeof(ksa.sigset)) != 0)
+ err(1, "rt_sigaction");
+ }
+ }
+}
+#else
+static void fix_sa_restorer(int sig)
+{
+ /* 64-bit glibc works fine. */
+}
+#endif
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+
+ fix_sa_restorer(sig);
+}
+
+static jmp_buf jmpbuf;
+
+static void sigsegv(int sig, siginfo_t *info, void *ctx_void)
+{
+ siglongjmp(jmpbuf, 1);
+}
+
+static void do_multicpu_tests(void)
+{
+ cpu_set_t cpuset;
+ pthread_t thread;
+ int failures = 0, iters = 5, i;
+ unsigned short orig_ss;
+
+ CPU_ZERO(&cpuset);
+ CPU_SET(1, &cpuset);
+ if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) {
+ printf("[SKIP]\tCannot set affinity to CPU 1\n");
+ return;
+ }
+
+ CPU_ZERO(&cpuset);
+ CPU_SET(0, &cpuset);
+ if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) {
+ printf("[SKIP]\tCannot set affinity to CPU 0\n");
+ return;
+ }
+
+ sethandler(SIGSEGV, sigsegv, 0);
+#ifdef __i386__
+ /* True 32-bit kernels send SIGILL instead of SIGSEGV on IRET faults. */
+ sethandler(SIGILL, sigsegv, 0);
+#endif
+
+ printf("[RUN]\tCross-CPU LDT invalidation\n");
+
+ if (pthread_create(&thread, 0, threadproc, 0) != 0)
+ err(1, "pthread_create");
+
+ asm volatile ("mov %%ss, %0" : "=rm" (orig_ss));
+
+ for (i = 0; i < 5; i++) {
+ if (sigsetjmp(jmpbuf, 1) != 0)
+ continue;
+
+ /* Make sure the thread is ready after the last test. */
+ while (ftx != 0)
+ ;
+
+ struct user_desc desc = {
+ .entry_number = 0,
+ .base_addr = 0,
+ .limit = 0xfffff,
+ .seg_32bit = 1,
+ .contents = 0, /* Data */
+ .read_exec_only = 0,
+ .limit_in_pages = 1,
+ .seg_not_present = 0,
+ .useable = 0
+ };
+
+ if (safe_modify_ldt(0x11, &desc, sizeof(desc)) != 0) {
+ if (errno != ENOSYS)
+ err(1, "modify_ldt");
+ printf("[SKIP]\tmodify_ldt unavailable\n");
+ break;
+ }
+
+ /* Arm the thread. */
+ ftx = 1;
+ syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0);
+
+ asm volatile ("mov %0, %%ss" : : "r" (0x7));
+
+ /* Go! */
+ ftx = 2;
+
+ while (ftx != 0)
+ ;
+
+ /*
+ * On success, modify_ldt will segfault us synchronously,
+ * and we'll escape via siglongjmp.
+ */
+
+ failures++;
+ asm volatile ("mov %0, %%ss" : : "rm" (orig_ss));
+ }
+
+ ftx = 100; /* Kill the thread. */
+ syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0);
+
+ if (pthread_join(thread, NULL) != 0)
+ err(1, "pthread_join");
+
+ if (failures) {
+ printf("[FAIL]\t%d of %d iterations failed\n", failures, iters);
+ nerrs++;
+ } else {
+ printf("[OK]\tAll %d iterations succeeded\n", iters);
+ }
+}
+
+static int finish_exec_test(void)
+{
+ /*
+ * Older kernel versions did inherit the LDT on exec() which is
+ * wrong because exec() starts from a clean state.
+ */
+ check_invalid_segment(0, 1);
+
+ return nerrs ? 1 : 0;
+}
+
+static void do_exec_test(void)
+{
+ printf("[RUN]\tTest exec\n");
+
+ struct user_desc desc = {
+ .entry_number = 0,
+ .base_addr = 0,
+ .limit = 42,
+ .seg_32bit = 1,
+ .contents = 2, /* Code, not conforming */
+ .read_exec_only = 0,
+ .limit_in_pages = 0,
+ .seg_not_present = 0,
+ .useable = 0
+ };
+ install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE | AR_S | AR_P | AR_DB);
+
+ pid_t child = fork();
+ if (child == 0) {
+ execl("/proc/self/exe", "ldt_gdt_test_exec", NULL);
+ printf("[FAIL]\tCould not exec self\n");
+ exit(1); /* exec failed */
+ } else {
+ int status;
+ if (waitpid(child, &status, 0) != child ||
+ !WIFEXITED(status)) {
+ printf("[FAIL]\tChild died\n");
+ nerrs++;
+ } else if (WEXITSTATUS(status) != 0) {
+ printf("[FAIL]\tChild failed\n");
+ nerrs++;
+ } else {
+ printf("[OK]\tChild succeeded\n");
+ }
+ }
+}
+
+static void setup_counter_page(void)
+{
+ unsigned int *page = mmap(NULL, 4096, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE | MAP_32BIT, -1, 0);
+ if (page == MAP_FAILED)
+ err(1, "mmap");
+
+ for (int i = 0; i < 1024; i++)
+ page[i] = i;
+ counter_page = page;
+}
+
+static int invoke_set_thread_area(void)
+{
+ int ret;
+ asm volatile ("int $0x80"
+ : "=a" (ret), "+m" (low_user_desc) :
+ "a" (243), "b" (low_user_desc)
+ : INT80_CLOBBERS);
+ return ret;
+}
+
+static void setup_low_user_desc(void)
+{
+ low_user_desc = mmap(NULL, 2 * sizeof(struct user_desc),
+ PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE | MAP_32BIT, -1, 0);
+ if (low_user_desc == MAP_FAILED)
+ err(1, "mmap");
+
+ low_user_desc->entry_number = -1;
+ low_user_desc->base_addr = (unsigned long)&counter_page[1];
+ low_user_desc->limit = 0xfffff;
+ low_user_desc->seg_32bit = 1;
+ low_user_desc->contents = 0; /* Data, grow-up*/
+ low_user_desc->read_exec_only = 0;
+ low_user_desc->limit_in_pages = 1;
+ low_user_desc->seg_not_present = 0;
+ low_user_desc->useable = 0;
+
+ if (invoke_set_thread_area() == 0) {
+ gdt_entry_num = low_user_desc->entry_number;
+ printf("[NOTE]\tset_thread_area is available; will use GDT index %d\n", gdt_entry_num);
+ } else {
+ printf("[NOTE]\tset_thread_area is unavailable\n");
+ }
+
+ low_user_desc_clear = low_user_desc + 1;
+ low_user_desc_clear->entry_number = gdt_entry_num;
+ low_user_desc_clear->read_exec_only = 1;
+ low_user_desc_clear->seg_not_present = 1;
+}
+
+static void test_gdt_invalidation(void)
+{
+ if (!gdt_entry_num)
+ return; /* 64-bit only system -- we can't use set_thread_area */
+
+ unsigned short prev_sel;
+ unsigned short sel;
+ unsigned int eax;
+ const char *result;
+#ifdef __x86_64__
+ unsigned long saved_base;
+ unsigned long new_base;
+#endif
+
+ /* Test DS */
+ invoke_set_thread_area();
+ eax = 243;
+ sel = (gdt_entry_num << 3) | 3;
+ asm volatile ("movw %%ds, %[prev_sel]\n\t"
+ "movw %[sel], %%ds\n\t"
+#ifdef __i386__
+ "pushl %%ebx\n\t"
+#endif
+ "movl %[arg1], %%ebx\n\t"
+ "int $0x80\n\t" /* Should invalidate ds */
+#ifdef __i386__
+ "popl %%ebx\n\t"
+#endif
+ "movw %%ds, %[sel]\n\t"
+ "movw %[prev_sel], %%ds"
+ : [prev_sel] "=&r" (prev_sel), [sel] "+r" (sel),
+ "+a" (eax)
+ : "m" (low_user_desc_clear),
+ [arg1] "r" ((unsigned int)(unsigned long)low_user_desc_clear)
+ : INT80_CLOBBERS);
+
+ if (sel != 0) {
+ result = "FAIL";
+ nerrs++;
+ } else {
+ result = "OK";
+ }
+ printf("[%s]\tInvalidate DS with set_thread_area: new DS = 0x%hx\n",
+ result, sel);
+
+ /* Test ES */
+ invoke_set_thread_area();
+ eax = 243;
+ sel = (gdt_entry_num << 3) | 3;
+ asm volatile ("movw %%es, %[prev_sel]\n\t"
+ "movw %[sel], %%es\n\t"
+#ifdef __i386__
+ "pushl %%ebx\n\t"
+#endif
+ "movl %[arg1], %%ebx\n\t"
+ "int $0x80\n\t" /* Should invalidate es */
+#ifdef __i386__
+ "popl %%ebx\n\t"
+#endif
+ "movw %%es, %[sel]\n\t"
+ "movw %[prev_sel], %%es"
+ : [prev_sel] "=&r" (prev_sel), [sel] "+r" (sel),
+ "+a" (eax)
+ : "m" (low_user_desc_clear),
+ [arg1] "r" ((unsigned int)(unsigned long)low_user_desc_clear)
+ : INT80_CLOBBERS);
+
+ if (sel != 0) {
+ result = "FAIL";
+ nerrs++;
+ } else {
+ result = "OK";
+ }
+ printf("[%s]\tInvalidate ES with set_thread_area: new ES = 0x%hx\n",
+ result, sel);
+
+ /* Test FS */
+ invoke_set_thread_area();
+ eax = 243;
+ sel = (gdt_entry_num << 3) | 3;
+#ifdef __x86_64__
+ syscall(SYS_arch_prctl, ARCH_GET_FS, &saved_base);
+#endif
+ asm volatile ("movw %%fs, %[prev_sel]\n\t"
+ "movw %[sel], %%fs\n\t"
+#ifdef __i386__
+ "pushl %%ebx\n\t"
+#endif
+ "movl %[arg1], %%ebx\n\t"
+ "int $0x80\n\t" /* Should invalidate fs */
+#ifdef __i386__
+ "popl %%ebx\n\t"
+#endif
+ "movw %%fs, %[sel]\n\t"
+ : [prev_sel] "=&r" (prev_sel), [sel] "+r" (sel),
+ "+a" (eax)
+ : "m" (low_user_desc_clear),
+ [arg1] "r" ((unsigned int)(unsigned long)low_user_desc_clear)
+ : INT80_CLOBBERS);
+
+#ifdef __x86_64__
+ syscall(SYS_arch_prctl, ARCH_GET_FS, &new_base);
+#endif
+
+ /* Restore FS/BASE for glibc */
+ asm volatile ("movw %[prev_sel], %%fs" : : [prev_sel] "rm" (prev_sel));
+#ifdef __x86_64__
+ if (saved_base)
+ syscall(SYS_arch_prctl, ARCH_SET_FS, saved_base);
+#endif
+
+ if (sel != 0) {
+ result = "FAIL";
+ nerrs++;
+ } else {
+ result = "OK";
+ }
+ printf("[%s]\tInvalidate FS with set_thread_area: new FS = 0x%hx\n",
+ result, sel);
+
+#ifdef __x86_64__
+ if (sel == 0 && new_base != 0) {
+ nerrs++;
+ printf("[FAIL]\tNew FSBASE was 0x%lx\n", new_base);
+ } else {
+ printf("[OK]\tNew FSBASE was zero\n");
+ }
+#endif
+
+ /* Test GS */
+ invoke_set_thread_area();
+ eax = 243;
+ sel = (gdt_entry_num << 3) | 3;
+#ifdef __x86_64__
+ syscall(SYS_arch_prctl, ARCH_GET_GS, &saved_base);
+#endif
+ asm volatile ("movw %%gs, %[prev_sel]\n\t"
+ "movw %[sel], %%gs\n\t"
+#ifdef __i386__
+ "pushl %%ebx\n\t"
+#endif
+ "movl %[arg1], %%ebx\n\t"
+ "int $0x80\n\t" /* Should invalidate gs */
+#ifdef __i386__
+ "popl %%ebx\n\t"
+#endif
+ "movw %%gs, %[sel]\n\t"
+ : [prev_sel] "=&r" (prev_sel), [sel] "+r" (sel),
+ "+a" (eax)
+ : "m" (low_user_desc_clear),
+ [arg1] "r" ((unsigned int)(unsigned long)low_user_desc_clear)
+ : INT80_CLOBBERS);
+
+#ifdef __x86_64__
+ syscall(SYS_arch_prctl, ARCH_GET_GS, &new_base);
+#endif
+
+ /* Restore GS/BASE for glibc */
+ asm volatile ("movw %[prev_sel], %%gs" : : [prev_sel] "rm" (prev_sel));
+#ifdef __x86_64__
+ if (saved_base)
+ syscall(SYS_arch_prctl, ARCH_SET_GS, saved_base);
+#endif
+
+ if (sel != 0) {
+ result = "FAIL";
+ nerrs++;
+ } else {
+ result = "OK";
+ }
+ printf("[%s]\tInvalidate GS with set_thread_area: new GS = 0x%hx\n",
+ result, sel);
+
+#ifdef __x86_64__
+ if (sel == 0 && new_base != 0) {
+ nerrs++;
+ printf("[FAIL]\tNew GSBASE was 0x%lx\n", new_base);
+ } else {
+ printf("[OK]\tNew GSBASE was zero\n");
+ }
+#endif
+}
+
+int main(int argc, char **argv)
+{
+ if (argc == 1 && !strcmp(argv[0], "ldt_gdt_test_exec"))
+ return finish_exec_test();
+
+ setup_counter_page();
+ setup_low_user_desc();
+
+ do_simple_tests();
+
+ do_multicpu_tests();
+
+ do_exec_test();
+
+ test_gdt_invalidation();
+
+ return nerrs ? 1 : 0;
+}
diff --git a/tools/testing/selftests/x86/mov_ss_trap.c b/tools/testing/selftests/x86/mov_ss_trap.c
new file mode 100644
index 000000000..cc3de6ff9
--- /dev/null
+++ b/tools/testing/selftests/x86/mov_ss_trap.c
@@ -0,0 +1,286 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * mov_ss_trap.c: Exercise the bizarre side effects of a watchpoint on MOV SS
+ *
+ * This does MOV SS from a watchpointed address followed by various
+ * types of kernel entries. A MOV SS that hits a watchpoint will queue
+ * up a #DB trap but will not actually deliver that trap. The trap
+ * will be delivered after the next instruction instead. The CPU's logic
+ * seems to be:
+ *
+ * - Any fault: drop the pending #DB trap.
+ * - INT $N, INT3, INTO, SYSCALL, SYSENTER: enter the kernel and then
+ * deliver #DB.
+ * - ICEBP: enter the kernel but do not deliver the watchpoint trap
+ * - breakpoint: only one #DB is delivered (phew!)
+ *
+ * There are plenty of ways for a kernel to handle this incorrectly. This
+ * test tries to exercise all the cases.
+ *
+ * This should mostly cover CVE-2018-1087 and CVE-2018-8897.
+ */
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <sys/ptrace.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/user.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <err.h>
+#include <string.h>
+#include <setjmp.h>
+#include <sys/prctl.h>
+
+#define X86_EFLAGS_RF (1UL << 16)
+
+#if __x86_64__
+# define REG_IP REG_RIP
+#else
+# define REG_IP REG_EIP
+#endif
+
+unsigned short ss;
+extern unsigned char breakpoint_insn[];
+sigjmp_buf jmpbuf;
+
+static void enable_watchpoint(void)
+{
+ pid_t parent = getpid();
+ int status;
+
+ pid_t child = fork();
+ if (child < 0)
+ err(1, "fork");
+
+ if (child) {
+ if (waitpid(child, &status, 0) != child)
+ err(1, "waitpid for child");
+ } else {
+ unsigned long dr0, dr1, dr7;
+
+ dr0 = (unsigned long)&ss;
+ dr1 = (unsigned long)breakpoint_insn;
+ dr7 = ((1UL << 1) | /* G0 */
+ (3UL << 16) | /* RW0 = read or write */
+ (1UL << 18) | /* LEN0 = 2 bytes */
+ (1UL << 3)); /* G1, RW1 = insn */
+
+ if (ptrace(PTRACE_ATTACH, parent, NULL, NULL) != 0)
+ err(1, "PTRACE_ATTACH");
+
+ if (waitpid(parent, &status, 0) != parent)
+ err(1, "waitpid for child");
+
+ if (ptrace(PTRACE_POKEUSER, parent, (void *)offsetof(struct user, u_debugreg[0]), dr0) != 0)
+ err(1, "PTRACE_POKEUSER DR0");
+
+ if (ptrace(PTRACE_POKEUSER, parent, (void *)offsetof(struct user, u_debugreg[1]), dr1) != 0)
+ err(1, "PTRACE_POKEUSER DR1");
+
+ if (ptrace(PTRACE_POKEUSER, parent, (void *)offsetof(struct user, u_debugreg[7]), dr7) != 0)
+ err(1, "PTRACE_POKEUSER DR7");
+
+ printf("\tDR0 = %lx, DR1 = %lx, DR7 = %lx\n", dr0, dr1, dr7);
+
+ if (ptrace(PTRACE_DETACH, parent, NULL, NULL) != 0)
+ err(1, "PTRACE_DETACH");
+
+ exit(0);
+ }
+}
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static char const * const signames[] = {
+ [SIGSEGV] = "SIGSEGV",
+ [SIGBUS] = "SIBGUS",
+ [SIGTRAP] = "SIGTRAP",
+ [SIGILL] = "SIGILL",
+};
+
+static void sigtrap(int sig, siginfo_t *si, void *ctx_void)
+{
+ ucontext_t *ctx = ctx_void;
+
+ printf("\tGot SIGTRAP with RIP=%lx, EFLAGS.RF=%d\n",
+ (unsigned long)ctx->uc_mcontext.gregs[REG_IP],
+ !!(ctx->uc_mcontext.gregs[REG_EFL] & X86_EFLAGS_RF));
+}
+
+static void handle_and_return(int sig, siginfo_t *si, void *ctx_void)
+{
+ ucontext_t *ctx = ctx_void;
+
+ printf("\tGot %s with RIP=%lx\n", signames[sig],
+ (unsigned long)ctx->uc_mcontext.gregs[REG_IP]);
+}
+
+static void handle_and_longjmp(int sig, siginfo_t *si, void *ctx_void)
+{
+ ucontext_t *ctx = ctx_void;
+
+ printf("\tGot %s with RIP=%lx\n", signames[sig],
+ (unsigned long)ctx->uc_mcontext.gregs[REG_IP]);
+
+ siglongjmp(jmpbuf, 1);
+}
+
+int main()
+{
+ unsigned long nr;
+
+ asm volatile ("mov %%ss, %[ss]" : [ss] "=m" (ss));
+ printf("\tSS = 0x%hx, &SS = 0x%p\n", ss, &ss);
+
+ if (prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY, 0, 0, 0) == 0)
+ printf("\tPR_SET_PTRACER_ANY succeeded\n");
+
+ printf("\tSet up a watchpoint\n");
+ sethandler(SIGTRAP, sigtrap, 0);
+ enable_watchpoint();
+
+ printf("[RUN]\tRead from watched memory (should get SIGTRAP)\n");
+ asm volatile ("mov %[ss], %[tmp]" : [tmp] "=r" (nr) : [ss] "m" (ss));
+
+ printf("[RUN]\tMOV SS; INT3\n");
+ asm volatile ("mov %[ss], %%ss; int3" :: [ss] "m" (ss));
+
+ printf("[RUN]\tMOV SS; INT 3\n");
+ asm volatile ("mov %[ss], %%ss; .byte 0xcd, 0x3" :: [ss] "m" (ss));
+
+ printf("[RUN]\tMOV SS; CS CS INT3\n");
+ asm volatile ("mov %[ss], %%ss; .byte 0x2e, 0x2e; int3" :: [ss] "m" (ss));
+
+ printf("[RUN]\tMOV SS; CSx14 INT3\n");
+ asm volatile ("mov %[ss], %%ss; .fill 14,1,0x2e; int3" :: [ss] "m" (ss));
+
+ printf("[RUN]\tMOV SS; INT 4\n");
+ sethandler(SIGSEGV, handle_and_return, SA_RESETHAND);
+ asm volatile ("mov %[ss], %%ss; int $4" :: [ss] "m" (ss));
+
+#ifdef __i386__
+ printf("[RUN]\tMOV SS; INTO\n");
+ sethandler(SIGSEGV, handle_and_return, SA_RESETHAND);
+ nr = -1;
+ asm volatile ("add $1, %[tmp]; mov %[ss], %%ss; into"
+ : [tmp] "+r" (nr) : [ss] "m" (ss));
+#endif
+
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ printf("[RUN]\tMOV SS; ICEBP\n");
+
+ /* Some emulators (e.g. QEMU TCG) don't emulate ICEBP. */
+ sethandler(SIGILL, handle_and_longjmp, SA_RESETHAND);
+
+ asm volatile ("mov %[ss], %%ss; .byte 0xf1" :: [ss] "m" (ss));
+ }
+
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ printf("[RUN]\tMOV SS; CLI\n");
+ sethandler(SIGSEGV, handle_and_longjmp, SA_RESETHAND);
+ asm volatile ("mov %[ss], %%ss; cli" :: [ss] "m" (ss));
+ }
+
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ printf("[RUN]\tMOV SS; #PF\n");
+ sethandler(SIGSEGV, handle_and_longjmp, SA_RESETHAND);
+ asm volatile ("mov %[ss], %%ss; mov (-1), %[tmp]"
+ : [tmp] "=r" (nr) : [ss] "m" (ss));
+ }
+
+ /*
+ * INT $1: if #DB has DPL=3 and there isn't special handling,
+ * then the kernel will die.
+ */
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ printf("[RUN]\tMOV SS; INT 1\n");
+ sethandler(SIGSEGV, handle_and_longjmp, SA_RESETHAND);
+ asm volatile ("mov %[ss], %%ss; int $1" :: [ss] "m" (ss));
+ }
+
+#ifdef __x86_64__
+ /*
+ * In principle, we should test 32-bit SYSCALL as well, but
+ * the calling convention is so unpredictable that it's
+ * not obviously worth the effort.
+ */
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ printf("[RUN]\tMOV SS; SYSCALL\n");
+ sethandler(SIGILL, handle_and_longjmp, SA_RESETHAND);
+ nr = SYS_getpid;
+ /*
+ * Toggle the high bit of RSP to make it noncanonical to
+ * strengthen this test on non-SMAP systems.
+ */
+ asm volatile ("btc $63, %%rsp\n\t"
+ "mov %[ss], %%ss; syscall\n\t"
+ "btc $63, %%rsp"
+ : "+a" (nr) : [ss] "m" (ss)
+ : "rcx"
+#ifdef __x86_64__
+ , "r11"
+#endif
+ );
+ }
+#endif
+
+ printf("[RUN]\tMOV SS; breakpointed NOP\n");
+ asm volatile ("mov %[ss], %%ss; breakpoint_insn: nop" :: [ss] "m" (ss));
+
+ /*
+ * Invoking SYSENTER directly breaks all the rules. Just handle
+ * the SIGSEGV.
+ */
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ printf("[RUN]\tMOV SS; SYSENTER\n");
+ stack_t stack = {
+ .ss_sp = malloc(sizeof(char) * SIGSTKSZ),
+ .ss_size = SIGSTKSZ,
+ };
+ if (sigaltstack(&stack, NULL) != 0)
+ err(1, "sigaltstack");
+ sethandler(SIGSEGV, handle_and_longjmp, SA_RESETHAND | SA_ONSTACK);
+ nr = SYS_getpid;
+ free(stack.ss_sp);
+ /* Clear EBP first to make sure we segfault cleanly. */
+ asm volatile ("xorl %%ebp, %%ebp; mov %[ss], %%ss; SYSENTER" : "+a" (nr)
+ : [ss] "m" (ss) : "flags", "rcx"
+#ifdef __x86_64__
+ , "r11"
+#endif
+ );
+
+ /* We're unreachable here. SYSENTER forgets RIP. */
+ }
+
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ printf("[RUN]\tMOV SS; INT $0x80\n");
+ sethandler(SIGSEGV, handle_and_longjmp, SA_RESETHAND);
+ nr = 20; /* compat getpid */
+ asm volatile ("mov %[ss], %%ss; int $0x80"
+ : "+a" (nr) : [ss] "m" (ss)
+ : "flags"
+#ifdef __x86_64__
+ , "r8", "r9", "r10", "r11"
+#endif
+ );
+ }
+
+ printf("[OK]\tI aten't dead\n");
+ return 0;
+}
diff --git a/tools/testing/selftests/x86/ptrace_syscall.c b/tools/testing/selftests/x86/ptrace_syscall.c
new file mode 100644
index 000000000..12aaa0631
--- /dev/null
+++ b/tools/testing/selftests/x86/ptrace_syscall.c
@@ -0,0 +1,430 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+
+#include <sys/ptrace.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/syscall.h>
+#include <sys/user.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <err.h>
+#include <string.h>
+#include <asm/ptrace-abi.h>
+#include <sys/auxv.h>
+
+/* Bitness-agnostic defines for user_regs_struct fields. */
+#ifdef __x86_64__
+# define user_syscall_nr orig_rax
+# define user_arg0 rdi
+# define user_arg1 rsi
+# define user_arg2 rdx
+# define user_arg3 r10
+# define user_arg4 r8
+# define user_arg5 r9
+# define user_ip rip
+# define user_ax rax
+#else
+# define user_syscall_nr orig_eax
+# define user_arg0 ebx
+# define user_arg1 ecx
+# define user_arg2 edx
+# define user_arg3 esi
+# define user_arg4 edi
+# define user_arg5 ebp
+# define user_ip eip
+# define user_ax eax
+#endif
+
+static int nerrs = 0;
+
+struct syscall_args32 {
+ uint32_t nr, arg0, arg1, arg2, arg3, arg4, arg5;
+};
+
+#ifdef __i386__
+extern void sys32_helper(struct syscall_args32 *, void *);
+extern void int80_and_ret(void);
+#endif
+
+/*
+ * Helper to invoke int80 with controlled regs and capture the final regs.
+ */
+static void do_full_int80(struct syscall_args32 *args)
+{
+#ifdef __x86_64__
+ register unsigned long bp asm("bp") = args->arg5;
+ asm volatile ("int $0x80"
+ : "+a" (args->nr),
+ "+b" (args->arg0), "+c" (args->arg1), "+d" (args->arg2),
+ "+S" (args->arg3), "+D" (args->arg4), "+r" (bp)
+ : : "r8", "r9", "r10", "r11");
+ args->arg5 = bp;
+#else
+ sys32_helper(args, int80_and_ret);
+#endif
+}
+
+#ifdef __i386__
+static void (*vsyscall32)(void);
+
+/*
+ * Nasty helper to invoke AT_SYSINFO (i.e. __kernel_vsyscall) with
+ * controlled regs and capture the final regs. This is so nasty that it
+ * crashes my copy of gdb :)
+ */
+static void do_full_vsyscall32(struct syscall_args32 *args)
+{
+ sys32_helper(args, vsyscall32);
+}
+#endif
+
+static siginfo_t wait_trap(pid_t chld)
+{
+ siginfo_t si;
+ if (waitid(P_PID, chld, &si, WEXITED|WSTOPPED) != 0)
+ err(1, "waitid");
+ if (si.si_pid != chld)
+ errx(1, "got unexpected pid in event\n");
+ if (si.si_code != CLD_TRAPPED)
+ errx(1, "got unexpected event type %d\n", si.si_code);
+ return si;
+}
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static void setsigign(int sig, int flags)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = (void *)SIG_IGN;
+ sa.sa_flags = flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static void clearhandler(int sig)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_handler = SIG_DFL;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+#ifdef __x86_64__
+# define REG_BP REG_RBP
+#else
+# define REG_BP REG_EBP
+#endif
+
+static void empty_handler(int sig, siginfo_t *si, void *ctx_void)
+{
+}
+
+static void test_sys32_regs(void (*do_syscall)(struct syscall_args32 *))
+{
+ struct syscall_args32 args = {
+ .nr = 224, /* gettid */
+ .arg0 = 10, .arg1 = 11, .arg2 = 12,
+ .arg3 = 13, .arg4 = 14, .arg5 = 15,
+ };
+
+ do_syscall(&args);
+
+ if (args.nr != getpid() ||
+ args.arg0 != 10 || args.arg1 != 11 || args.arg2 != 12 ||
+ args.arg3 != 13 || args.arg4 != 14 || args.arg5 != 15) {
+ printf("[FAIL]\tgetpid() failed to preserve regs\n");
+ nerrs++;
+ } else {
+ printf("[OK]\tgetpid() preserves regs\n");
+ }
+
+ sethandler(SIGUSR1, empty_handler, 0);
+
+ args.nr = 37; /* kill */
+ args.arg0 = getpid();
+ args.arg1 = SIGUSR1;
+ do_syscall(&args);
+ if (args.nr != 0 ||
+ args.arg0 != getpid() || args.arg1 != SIGUSR1 || args.arg2 != 12 ||
+ args.arg3 != 13 || args.arg4 != 14 || args.arg5 != 15) {
+ printf("[FAIL]\tkill(getpid(), SIGUSR1) failed to preserve regs\n");
+ nerrs++;
+ } else {
+ printf("[OK]\tkill(getpid(), SIGUSR1) preserves regs\n");
+ }
+ clearhandler(SIGUSR1);
+}
+
+static void test_ptrace_syscall_restart(void)
+{
+ printf("[RUN]\tptrace-induced syscall restart\n");
+ pid_t chld = fork();
+ if (chld < 0)
+ err(1, "fork");
+
+ if (chld == 0) {
+ if (ptrace(PTRACE_TRACEME, 0, 0, 0) != 0)
+ err(1, "PTRACE_TRACEME");
+
+ pid_t pid = getpid(), tid = syscall(SYS_gettid);
+
+ printf("\tChild will make one syscall\n");
+ syscall(SYS_tgkill, pid, tid, SIGSTOP);
+
+ syscall(SYS_gettid, 10, 11, 12, 13, 14, 15);
+ _exit(0);
+ }
+
+ int status;
+
+ /* Wait for SIGSTOP. */
+ if (waitpid(chld, &status, 0) != chld || !WIFSTOPPED(status))
+ err(1, "waitpid");
+
+ struct user_regs_struct regs;
+
+ printf("[RUN]\tSYSEMU\n");
+ if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
+ err(1, "PTRACE_SYSEMU");
+ wait_trap(chld);
+
+ if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)
+ err(1, "PTRACE_GETREGS");
+
+ if (regs.user_syscall_nr != SYS_gettid ||
+ regs.user_arg0 != 10 || regs.user_arg1 != 11 ||
+ regs.user_arg2 != 12 || regs.user_arg3 != 13 ||
+ regs.user_arg4 != 14 || regs.user_arg5 != 15) {
+ printf("[FAIL]\tInitial args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
+ nerrs++;
+ } else {
+ printf("[OK]\tInitial nr and args are correct\n");
+ }
+
+ printf("[RUN]\tRestart the syscall (ip = 0x%lx)\n",
+ (unsigned long)regs.user_ip);
+
+ /*
+ * This does exactly what it appears to do if syscall is int80 or
+ * SYSCALL64. For SYSCALL32 or SYSENTER, though, this is highly
+ * magical. It needs to work so that ptrace and syscall restart
+ * work as expected.
+ */
+ regs.user_ax = regs.user_syscall_nr;
+ regs.user_ip -= 2;
+ if (ptrace(PTRACE_SETREGS, chld, 0, &regs) != 0)
+ err(1, "PTRACE_SETREGS");
+
+ if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
+ err(1, "PTRACE_SYSEMU");
+ wait_trap(chld);
+
+ if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)
+ err(1, "PTRACE_GETREGS");
+
+ if (regs.user_syscall_nr != SYS_gettid ||
+ regs.user_arg0 != 10 || regs.user_arg1 != 11 ||
+ regs.user_arg2 != 12 || regs.user_arg3 != 13 ||
+ regs.user_arg4 != 14 || regs.user_arg5 != 15) {
+ printf("[FAIL]\tRestart nr or args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
+ nerrs++;
+ } else {
+ printf("[OK]\tRestarted nr and args are correct\n");
+ }
+
+ printf("[RUN]\tChange nr and args and restart the syscall (ip = 0x%lx)\n",
+ (unsigned long)regs.user_ip);
+
+ regs.user_ax = SYS_getpid;
+ regs.user_arg0 = 20;
+ regs.user_arg1 = 21;
+ regs.user_arg2 = 22;
+ regs.user_arg3 = 23;
+ regs.user_arg4 = 24;
+ regs.user_arg5 = 25;
+ regs.user_ip -= 2;
+
+ if (ptrace(PTRACE_SETREGS, chld, 0, &regs) != 0)
+ err(1, "PTRACE_SETREGS");
+
+ if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
+ err(1, "PTRACE_SYSEMU");
+ wait_trap(chld);
+
+ if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)
+ err(1, "PTRACE_GETREGS");
+
+ if (regs.user_syscall_nr != SYS_getpid ||
+ regs.user_arg0 != 20 || regs.user_arg1 != 21 || regs.user_arg2 != 22 ||
+ regs.user_arg3 != 23 || regs.user_arg4 != 24 || regs.user_arg5 != 25) {
+ printf("[FAIL]\tRestart nr or args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
+ nerrs++;
+ } else {
+ printf("[OK]\tReplacement nr and args are correct\n");
+ }
+
+ if (ptrace(PTRACE_CONT, chld, 0, 0) != 0)
+ err(1, "PTRACE_CONT");
+ if (waitpid(chld, &status, 0) != chld)
+ err(1, "waitpid");
+ if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+ printf("[FAIL]\tChild failed\n");
+ nerrs++;
+ } else {
+ printf("[OK]\tChild exited cleanly\n");
+ }
+}
+
+static void test_restart_under_ptrace(void)
+{
+ printf("[RUN]\tkernel syscall restart under ptrace\n");
+ pid_t chld = fork();
+ if (chld < 0)
+ err(1, "fork");
+
+ if (chld == 0) {
+ if (ptrace(PTRACE_TRACEME, 0, 0, 0) != 0)
+ err(1, "PTRACE_TRACEME");
+
+ pid_t pid = getpid(), tid = syscall(SYS_gettid);
+
+ printf("\tChild will take a nap until signaled\n");
+ setsigign(SIGUSR1, SA_RESTART);
+ syscall(SYS_tgkill, pid, tid, SIGSTOP);
+
+ syscall(SYS_pause, 0, 0, 0, 0, 0, 0);
+ _exit(0);
+ }
+
+ int status;
+
+ /* Wait for SIGSTOP. */
+ if (waitpid(chld, &status, 0) != chld || !WIFSTOPPED(status))
+ err(1, "waitpid");
+
+ struct user_regs_struct regs;
+
+ printf("[RUN]\tSYSCALL\n");
+ if (ptrace(PTRACE_SYSCALL, chld, 0, 0) != 0)
+ err(1, "PTRACE_SYSCALL");
+ wait_trap(chld);
+
+ /* We should be stopped at pause(2) entry. */
+
+ if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)
+ err(1, "PTRACE_GETREGS");
+
+ if (regs.user_syscall_nr != SYS_pause ||
+ regs.user_arg0 != 0 || regs.user_arg1 != 0 ||
+ regs.user_arg2 != 0 || regs.user_arg3 != 0 ||
+ regs.user_arg4 != 0 || regs.user_arg5 != 0) {
+ printf("[FAIL]\tInitial args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
+ nerrs++;
+ } else {
+ printf("[OK]\tInitial nr and args are correct\n");
+ }
+
+ /* Interrupt it. */
+ kill(chld, SIGUSR1);
+
+ /* Advance. We should be stopped at exit. */
+ printf("[RUN]\tSYSCALL\n");
+ if (ptrace(PTRACE_SYSCALL, chld, 0, 0) != 0)
+ err(1, "PTRACE_SYSCALL");
+ wait_trap(chld);
+
+ if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)
+ err(1, "PTRACE_GETREGS");
+
+ if (regs.user_syscall_nr != SYS_pause ||
+ regs.user_arg0 != 0 || regs.user_arg1 != 0 ||
+ regs.user_arg2 != 0 || regs.user_arg3 != 0 ||
+ regs.user_arg4 != 0 || regs.user_arg5 != 0) {
+ printf("[FAIL]\tArgs after SIGUSR1 are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
+ nerrs++;
+ } else {
+ printf("[OK]\tArgs after SIGUSR1 are correct (ax = %ld)\n",
+ (long)regs.user_ax);
+ }
+
+ /* Poke the regs back in. This must not break anything. */
+ if (ptrace(PTRACE_SETREGS, chld, 0, &regs) != 0)
+ err(1, "PTRACE_SETREGS");
+
+ /* Catch the (ignored) SIGUSR1. */
+ if (ptrace(PTRACE_CONT, chld, 0, 0) != 0)
+ err(1, "PTRACE_CONT");
+ if (waitpid(chld, &status, 0) != chld)
+ err(1, "waitpid");
+ if (!WIFSTOPPED(status)) {
+ printf("[FAIL]\tChild was stopped for SIGUSR1 (status = 0x%x)\n", status);
+ nerrs++;
+ } else {
+ printf("[OK]\tChild got SIGUSR1\n");
+ }
+
+ /* The next event should be pause(2) again. */
+ printf("[RUN]\tStep again\n");
+ if (ptrace(PTRACE_SYSCALL, chld, 0, 0) != 0)
+ err(1, "PTRACE_SYSCALL");
+ wait_trap(chld);
+
+ /* We should be stopped at pause(2) entry. */
+
+ if (ptrace(PTRACE_GETREGS, chld, 0, &regs) != 0)
+ err(1, "PTRACE_GETREGS");
+
+ if (regs.user_syscall_nr != SYS_pause ||
+ regs.user_arg0 != 0 || regs.user_arg1 != 0 ||
+ regs.user_arg2 != 0 || regs.user_arg3 != 0 ||
+ regs.user_arg4 != 0 || regs.user_arg5 != 0) {
+ printf("[FAIL]\tpause did not restart (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
+ nerrs++;
+ } else {
+ printf("[OK]\tpause(2) restarted correctly\n");
+ }
+
+ /* Kill it. */
+ kill(chld, SIGKILL);
+ if (waitpid(chld, &status, 0) != chld)
+ err(1, "waitpid");
+}
+
+int main()
+{
+ printf("[RUN]\tCheck int80 return regs\n");
+ test_sys32_regs(do_full_int80);
+
+#if defined(__i386__) && (!defined(__GLIBC__) || __GLIBC__ > 2 || __GLIBC_MINOR__ >= 16)
+ vsyscall32 = (void *)getauxval(AT_SYSINFO);
+ if (vsyscall32) {
+ printf("[RUN]\tCheck AT_SYSINFO return regs\n");
+ test_sys32_regs(do_full_vsyscall32);
+ } else {
+ printf("[SKIP]\tAT_SYSINFO is not available\n");
+ }
+#endif
+
+ test_ptrace_syscall_restart();
+
+ test_restart_under_ptrace();
+
+ return 0;
+}
diff --git a/tools/testing/selftests/x86/raw_syscall_helper_32.S b/tools/testing/selftests/x86/raw_syscall_helper_32.S
new file mode 100644
index 000000000..a10d36afd
--- /dev/null
+++ b/tools/testing/selftests/x86/raw_syscall_helper_32.S
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+.global sys32_helper
+sys32_helper:
+ /* Args: syscall_args_32*, function pointer */
+ pushl %ebp
+ pushl %ebx
+ pushl %esi
+ pushl %edi
+ movl 5*4(%esp), %eax /* pointer to args struct */
+
+ movl 1*4(%eax), %ebx
+ movl 2*4(%eax), %ecx
+ movl 3*4(%eax), %edx
+ movl 4*4(%eax), %esi
+ movl 5*4(%eax), %edi
+ movl 6*4(%eax), %ebp
+ movl 0*4(%eax), %eax
+
+ call *(6*4)(%esp) /* Do the syscall */
+
+ /* Now we need to recover without losing any reg values */
+ pushl %eax
+ movl 6*4(%esp), %eax
+ popl 0*4(%eax)
+ movl %ebx, 1*4(%eax)
+ movl %ecx, 2*4(%eax)
+ movl %edx, 3*4(%eax)
+ movl %esi, 4*4(%eax)
+ movl %edi, 5*4(%eax)
+ movl %ebp, 6*4(%eax)
+
+ popl %edi
+ popl %esi
+ popl %ebx
+ popl %ebp
+ ret
+
+ .type sys32_helper, @function
+ .size sys32_helper, .-sys32_helper
+
+.global int80_and_ret
+int80_and_ret:
+ int $0x80
+ ret
+
+ .type int80_and_ret, @function
+ .size int80_and_ret, .-int80_and_ret
+
+.section .note.GNU-stack,"",%progbits
diff --git a/tools/testing/selftests/x86/sigaltstack.c b/tools/testing/selftests/x86/sigaltstack.c
new file mode 100644
index 000000000..f689af75e
--- /dev/null
+++ b/tools/testing/selftests/x86/sigaltstack.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define _GNU_SOURCE
+#include <signal.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <string.h>
+#include <err.h>
+#include <errno.h>
+#include <limits.h>
+#include <sys/mman.h>
+#include <sys/auxv.h>
+#include <sys/prctl.h>
+#include <sys/resource.h>
+#include <setjmp.h>
+
+/* sigaltstack()-enforced minimum stack */
+#define ENFORCED_MINSIGSTKSZ 2048
+
+#ifndef AT_MINSIGSTKSZ
+# define AT_MINSIGSTKSZ 51
+#endif
+
+static int nerrs;
+
+static bool sigalrm_expected;
+
+static unsigned long at_minstack_size;
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static void clearhandler(int sig)
+{
+ struct sigaction sa;
+
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_handler = SIG_DFL;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static int setup_altstack(void *start, unsigned long size)
+{
+ stack_t ss;
+
+ memset(&ss, 0, sizeof(ss));
+ ss.ss_size = size;
+ ss.ss_sp = start;
+
+ return sigaltstack(&ss, NULL);
+}
+
+static jmp_buf jmpbuf;
+
+static void sigsegv(int sig, siginfo_t *info, void *ctx_void)
+{
+ if (sigalrm_expected) {
+ printf("[FAIL]\tWrong signal delivered: SIGSEGV (expected SIGALRM).");
+ nerrs++;
+ } else {
+ printf("[OK]\tSIGSEGV signal delivered.\n");
+ }
+
+ siglongjmp(jmpbuf, 1);
+}
+
+static void sigalrm(int sig, siginfo_t *info, void *ctx_void)
+{
+ if (!sigalrm_expected) {
+ printf("[FAIL]\tWrong signal delivered: SIGALRM (expected SIGSEGV).");
+ nerrs++;
+ } else {
+ printf("[OK]\tSIGALRM signal delivered.\n");
+ }
+}
+
+static void test_sigaltstack(void *altstack, unsigned long size)
+{
+ if (setup_altstack(altstack, size))
+ err(1, "sigaltstack()");
+
+ sigalrm_expected = (size > at_minstack_size) ? true : false;
+
+ sethandler(SIGSEGV, sigsegv, 0);
+ sethandler(SIGALRM, sigalrm, SA_ONSTACK);
+
+ if (!sigsetjmp(jmpbuf, 1)) {
+ printf("[RUN]\tTest an alternate signal stack of %ssufficient size.\n",
+ sigalrm_expected ? "" : "in");
+ printf("\tRaise SIGALRM. %s is expected to be delivered.\n",
+ sigalrm_expected ? "It" : "SIGSEGV");
+ raise(SIGALRM);
+ }
+
+ clearhandler(SIGALRM);
+ clearhandler(SIGSEGV);
+}
+
+int main(void)
+{
+ void *altstack;
+
+ at_minstack_size = getauxval(AT_MINSIGSTKSZ);
+
+ altstack = mmap(NULL, at_minstack_size + SIGSTKSZ, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
+ if (altstack == MAP_FAILED)
+ err(1, "mmap()");
+
+ if ((ENFORCED_MINSIGSTKSZ + 1) < at_minstack_size)
+ test_sigaltstack(altstack, ENFORCED_MINSIGSTKSZ + 1);
+
+ test_sigaltstack(altstack, at_minstack_size + SIGSTKSZ);
+
+ return nerrs == 0 ? 0 : 1;
+}
diff --git a/tools/testing/selftests/x86/sigreturn.c b/tools/testing/selftests/x86/sigreturn.c
new file mode 100644
index 000000000..5d7961a5f
--- /dev/null
+++ b/tools/testing/selftests/x86/sigreturn.c
@@ -0,0 +1,875 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sigreturn.c - tests for x86 sigreturn(2) and exit-to-userspace
+ * Copyright (c) 2014-2015 Andrew Lutomirski
+ *
+ * This is a series of tests that exercises the sigreturn(2) syscall and
+ * the IRET / SYSRET paths in the kernel.
+ *
+ * For now, this focuses on the effects of unusual CS and SS values,
+ * and it has a bunch of tests to make sure that ESP/RSP is restored
+ * properly.
+ *
+ * The basic idea behind these tests is to raise(SIGUSR1) to create a
+ * sigcontext frame, plug in the values to be tested, and then return,
+ * which implicitly invokes sigreturn(2) and programs the user context
+ * as desired.
+ *
+ * For tests for which we expect sigreturn and the subsequent return to
+ * user mode to succeed, we return to a short trampoline that generates
+ * SIGTRAP so that the meat of the tests can be ordinary C code in a
+ * SIGTRAP handler.
+ *
+ * The inner workings of each test is documented below.
+ *
+ * Do not run on outdated, unpatched kernels at risk of nasty crashes.
+ */
+
+#define _GNU_SOURCE
+
+#include <sys/time.h>
+#include <time.h>
+#include <stdlib.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <inttypes.h>
+#include <sys/mman.h>
+#include <sys/signal.h>
+#include <sys/ucontext.h>
+#include <asm/ldt.h>
+#include <err.h>
+#include <setjmp.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include <sys/ptrace.h>
+#include <sys/user.h>
+
+/* Pull in AR_xyz defines. */
+typedef unsigned int u32;
+typedef unsigned short u16;
+#include "../../../../arch/x86/include/asm/desc_defs.h"
+
+/*
+ * Copied from asm/ucontext.h, as asm/ucontext.h conflicts badly with the glibc
+ * headers.
+ */
+#ifdef __x86_64__
+/*
+ * UC_SIGCONTEXT_SS will be set when delivering 64-bit or x32 signals on
+ * kernels that save SS in the sigcontext. All kernels that set
+ * UC_SIGCONTEXT_SS will correctly restore at least the low 32 bits of esp
+ * regardless of SS (i.e. they implement espfix).
+ *
+ * Kernels that set UC_SIGCONTEXT_SS will also set UC_STRICT_RESTORE_SS
+ * when delivering a signal that came from 64-bit code.
+ *
+ * Sigreturn restores SS as follows:
+ *
+ * if (saved SS is valid || UC_STRICT_RESTORE_SS is set ||
+ * saved CS is not 64-bit)
+ * new SS = saved SS (will fail IRET and signal if invalid)
+ * else
+ * new SS = a flat 32-bit data segment
+ */
+#define UC_SIGCONTEXT_SS 0x2
+#define UC_STRICT_RESTORE_SS 0x4
+#endif
+
+/*
+ * In principle, this test can run on Linux emulation layers (e.g.
+ * Illumos "LX branded zones"). Solaris-based kernels reserve LDT
+ * entries 0-5 for their own internal purposes, so start our LDT
+ * allocations above that reservation. (The tests don't pass on LX
+ * branded zones, but at least this lets them run.)
+ */
+#define LDT_OFFSET 6
+
+/* An aligned stack accessible through some of our segments. */
+static unsigned char stack16[65536] __attribute__((aligned(4096)));
+
+/*
+ * An aligned int3 instruction used as a trampoline. Some of the tests
+ * want to fish out their ss values, so this trampoline copies ss to eax
+ * before the int3.
+ */
+asm (".pushsection .text\n\t"
+ ".type int3, @function\n\t"
+ ".align 4096\n\t"
+ "int3:\n\t"
+ "mov %ss,%ecx\n\t"
+ "int3\n\t"
+ ".size int3, . - int3\n\t"
+ ".align 4096, 0xcc\n\t"
+ ".popsection");
+extern char int3[4096];
+
+/*
+ * At startup, we prepapre:
+ *
+ * - ldt_nonexistent_sel: An LDT entry that doesn't exist (all-zero
+ * descriptor or out of bounds).
+ * - code16_sel: A 16-bit LDT code segment pointing to int3.
+ * - data16_sel: A 16-bit LDT data segment pointing to stack16.
+ * - npcode32_sel: A 32-bit not-present LDT code segment pointing to int3.
+ * - npdata32_sel: A 32-bit not-present LDT data segment pointing to stack16.
+ * - gdt_data16_idx: A 16-bit GDT data segment pointing to stack16.
+ * - gdt_npdata32_idx: A 32-bit not-present GDT data segment pointing to
+ * stack16.
+ *
+ * For no particularly good reason, xyz_sel is a selector value with the
+ * RPL and LDT bits filled in, whereas xyz_idx is just an index into the
+ * descriptor table. These variables will be zero if their respective
+ * segments could not be allocated.
+ */
+static unsigned short ldt_nonexistent_sel;
+static unsigned short code16_sel, data16_sel, npcode32_sel, npdata32_sel;
+
+static unsigned short gdt_data16_idx, gdt_npdata32_idx;
+
+static unsigned short GDT3(int idx)
+{
+ return (idx << 3) | 3;
+}
+
+static unsigned short LDT3(int idx)
+{
+ return (idx << 3) | 7;
+}
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static void clearhandler(int sig)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_handler = SIG_DFL;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static void add_ldt(const struct user_desc *desc, unsigned short *var,
+ const char *name)
+{
+ if (syscall(SYS_modify_ldt, 1, desc, sizeof(*desc)) == 0) {
+ *var = LDT3(desc->entry_number);
+ } else {
+ printf("[NOTE]\tFailed to create %s segment\n", name);
+ *var = 0;
+ }
+}
+
+static void setup_ldt(void)
+{
+ if ((unsigned long)stack16 > (1ULL << 32) - sizeof(stack16))
+ errx(1, "stack16 is too high\n");
+ if ((unsigned long)int3 > (1ULL << 32) - sizeof(int3))
+ errx(1, "int3 is too high\n");
+
+ ldt_nonexistent_sel = LDT3(LDT_OFFSET + 2);
+
+ const struct user_desc code16_desc = {
+ .entry_number = LDT_OFFSET + 0,
+ .base_addr = (unsigned long)int3,
+ .limit = 4095,
+ .seg_32bit = 0,
+ .contents = 2, /* Code, not conforming */
+ .read_exec_only = 0,
+ .limit_in_pages = 0,
+ .seg_not_present = 0,
+ .useable = 0
+ };
+ add_ldt(&code16_desc, &code16_sel, "code16");
+
+ const struct user_desc data16_desc = {
+ .entry_number = LDT_OFFSET + 1,
+ .base_addr = (unsigned long)stack16,
+ .limit = 0xffff,
+ .seg_32bit = 0,
+ .contents = 0, /* Data, grow-up */
+ .read_exec_only = 0,
+ .limit_in_pages = 0,
+ .seg_not_present = 0,
+ .useable = 0
+ };
+ add_ldt(&data16_desc, &data16_sel, "data16");
+
+ const struct user_desc npcode32_desc = {
+ .entry_number = LDT_OFFSET + 3,
+ .base_addr = (unsigned long)int3,
+ .limit = 4095,
+ .seg_32bit = 1,
+ .contents = 2, /* Code, not conforming */
+ .read_exec_only = 0,
+ .limit_in_pages = 0,
+ .seg_not_present = 1,
+ .useable = 0
+ };
+ add_ldt(&npcode32_desc, &npcode32_sel, "npcode32");
+
+ const struct user_desc npdata32_desc = {
+ .entry_number = LDT_OFFSET + 4,
+ .base_addr = (unsigned long)stack16,
+ .limit = 0xffff,
+ .seg_32bit = 1,
+ .contents = 0, /* Data, grow-up */
+ .read_exec_only = 0,
+ .limit_in_pages = 0,
+ .seg_not_present = 1,
+ .useable = 0
+ };
+ add_ldt(&npdata32_desc, &npdata32_sel, "npdata32");
+
+ struct user_desc gdt_data16_desc = {
+ .entry_number = -1,
+ .base_addr = (unsigned long)stack16,
+ .limit = 0xffff,
+ .seg_32bit = 0,
+ .contents = 0, /* Data, grow-up */
+ .read_exec_only = 0,
+ .limit_in_pages = 0,
+ .seg_not_present = 0,
+ .useable = 0
+ };
+
+ if (syscall(SYS_set_thread_area, &gdt_data16_desc) == 0) {
+ /*
+ * This probably indicates vulnerability to CVE-2014-8133.
+ * Merely getting here isn't definitive, though, and we'll
+ * diagnose the problem for real later on.
+ */
+ printf("[WARN]\tset_thread_area allocated data16 at index %d\n",
+ gdt_data16_desc.entry_number);
+ gdt_data16_idx = gdt_data16_desc.entry_number;
+ } else {
+ printf("[OK]\tset_thread_area refused 16-bit data\n");
+ }
+
+ struct user_desc gdt_npdata32_desc = {
+ .entry_number = -1,
+ .base_addr = (unsigned long)stack16,
+ .limit = 0xffff,
+ .seg_32bit = 1,
+ .contents = 0, /* Data, grow-up */
+ .read_exec_only = 0,
+ .limit_in_pages = 0,
+ .seg_not_present = 1,
+ .useable = 0
+ };
+
+ if (syscall(SYS_set_thread_area, &gdt_npdata32_desc) == 0) {
+ /*
+ * As a hardening measure, newer kernels don't allow this.
+ */
+ printf("[WARN]\tset_thread_area allocated npdata32 at index %d\n",
+ gdt_npdata32_desc.entry_number);
+ gdt_npdata32_idx = gdt_npdata32_desc.entry_number;
+ } else {
+ printf("[OK]\tset_thread_area refused 16-bit data\n");
+ }
+}
+
+/* State used by our signal handlers. */
+static gregset_t initial_regs, requested_regs, resulting_regs;
+
+/* Instructions for the SIGUSR1 handler. */
+static volatile unsigned short sig_cs, sig_ss;
+static volatile sig_atomic_t sig_trapped, sig_err, sig_trapno;
+#ifdef __x86_64__
+static volatile sig_atomic_t sig_corrupt_final_ss;
+#endif
+
+/* Abstractions for some 32-bit vs 64-bit differences. */
+#ifdef __x86_64__
+# define REG_IP REG_RIP
+# define REG_SP REG_RSP
+# define REG_CX REG_RCX
+
+struct selectors {
+ unsigned short cs, gs, fs, ss;
+};
+
+static unsigned short *ssptr(ucontext_t *ctx)
+{
+ struct selectors *sels = (void *)&ctx->uc_mcontext.gregs[REG_CSGSFS];
+ return &sels->ss;
+}
+
+static unsigned short *csptr(ucontext_t *ctx)
+{
+ struct selectors *sels = (void *)&ctx->uc_mcontext.gregs[REG_CSGSFS];
+ return &sels->cs;
+}
+#else
+# define REG_IP REG_EIP
+# define REG_SP REG_ESP
+# define REG_CX REG_ECX
+
+static greg_t *ssptr(ucontext_t *ctx)
+{
+ return &ctx->uc_mcontext.gregs[REG_SS];
+}
+
+static greg_t *csptr(ucontext_t *ctx)
+{
+ return &ctx->uc_mcontext.gregs[REG_CS];
+}
+#endif
+
+/*
+ * Checks a given selector for its code bitness or returns -1 if it's not
+ * a usable code segment selector.
+ */
+int cs_bitness(unsigned short cs)
+{
+ uint32_t valid = 0, ar;
+ asm ("lar %[cs], %[ar]\n\t"
+ "jnz 1f\n\t"
+ "mov $1, %[valid]\n\t"
+ "1:"
+ : [ar] "=r" (ar), [valid] "+rm" (valid)
+ : [cs] "r" (cs));
+
+ if (!valid)
+ return -1;
+
+ bool db = (ar & (1 << 22));
+ bool l = (ar & (1 << 21));
+
+ if (!(ar & (1<<11)))
+ return -1; /* Not code. */
+
+ if (l && !db)
+ return 64;
+ else if (!l && db)
+ return 32;
+ else if (!l && !db)
+ return 16;
+ else
+ return -1; /* Unknown bitness. */
+}
+
+/*
+ * Checks a given selector for its code bitness or returns -1 if it's not
+ * a usable code segment selector.
+ */
+bool is_valid_ss(unsigned short cs)
+{
+ uint32_t valid = 0, ar;
+ asm ("lar %[cs], %[ar]\n\t"
+ "jnz 1f\n\t"
+ "mov $1, %[valid]\n\t"
+ "1:"
+ : [ar] "=r" (ar), [valid] "+rm" (valid)
+ : [cs] "r" (cs));
+
+ if (!valid)
+ return false;
+
+ if ((ar & AR_TYPE_MASK) != AR_TYPE_RWDATA &&
+ (ar & AR_TYPE_MASK) != AR_TYPE_RWDATA_EXPDOWN)
+ return false;
+
+ return (ar & AR_P);
+}
+
+/* Number of errors in the current test case. */
+static volatile sig_atomic_t nerrs;
+
+static void validate_signal_ss(int sig, ucontext_t *ctx)
+{
+#ifdef __x86_64__
+ bool was_64bit = (cs_bitness(*csptr(ctx)) == 64);
+
+ if (!(ctx->uc_flags & UC_SIGCONTEXT_SS)) {
+ printf("[FAIL]\tUC_SIGCONTEXT_SS was not set\n");
+ nerrs++;
+
+ /*
+ * This happens on Linux 4.1. The rest will fail, too, so
+ * return now to reduce the noise.
+ */
+ return;
+ }
+
+ /* UC_STRICT_RESTORE_SS is set iff we came from 64-bit mode. */
+ if (!!(ctx->uc_flags & UC_STRICT_RESTORE_SS) != was_64bit) {
+ printf("[FAIL]\tUC_STRICT_RESTORE_SS was wrong in signal %d\n",
+ sig);
+ nerrs++;
+ }
+
+ if (is_valid_ss(*ssptr(ctx))) {
+ /*
+ * DOSEMU was written before 64-bit sigcontext had SS, and
+ * it tries to figure out the signal source SS by looking at
+ * the physical register. Make sure that keeps working.
+ */
+ unsigned short hw_ss;
+ asm ("mov %%ss, %0" : "=rm" (hw_ss));
+ if (hw_ss != *ssptr(ctx)) {
+ printf("[FAIL]\tHW SS didn't match saved SS\n");
+ nerrs++;
+ }
+ }
+#endif
+}
+
+/*
+ * SIGUSR1 handler. Sets CS and SS as requested and points IP to the
+ * int3 trampoline. Sets SP to a large known value so that we can see
+ * whether the value round-trips back to user mode correctly.
+ */
+static void sigusr1(int sig, siginfo_t *info, void *ctx_void)
+{
+ ucontext_t *ctx = (ucontext_t*)ctx_void;
+
+ validate_signal_ss(sig, ctx);
+
+ memcpy(&initial_regs, &ctx->uc_mcontext.gregs, sizeof(gregset_t));
+
+ *csptr(ctx) = sig_cs;
+ *ssptr(ctx) = sig_ss;
+
+ ctx->uc_mcontext.gregs[REG_IP] =
+ sig_cs == code16_sel ? 0 : (unsigned long)&int3;
+ ctx->uc_mcontext.gregs[REG_SP] = (unsigned long)0x8badf00d5aadc0deULL;
+ ctx->uc_mcontext.gregs[REG_CX] = 0;
+
+#ifdef __i386__
+ /*
+ * Make sure the kernel doesn't inadvertently use DS or ES-relative
+ * accesses in a region where user DS or ES is loaded.
+ *
+ * Skip this for 64-bit builds because long mode doesn't care about
+ * DS and ES and skipping it increases test coverage a little bit,
+ * since 64-bit kernels can still run the 32-bit build.
+ */
+ ctx->uc_mcontext.gregs[REG_DS] = 0;
+ ctx->uc_mcontext.gregs[REG_ES] = 0;
+#endif
+
+ memcpy(&requested_regs, &ctx->uc_mcontext.gregs, sizeof(gregset_t));
+ requested_regs[REG_CX] = *ssptr(ctx); /* The asm code does this. */
+
+ return;
+}
+
+/*
+ * Called after a successful sigreturn (via int3) or from a failed
+ * sigreturn (directly by kernel). Restores our state so that the
+ * original raise(SIGUSR1) returns.
+ */
+static void sigtrap(int sig, siginfo_t *info, void *ctx_void)
+{
+ ucontext_t *ctx = (ucontext_t*)ctx_void;
+
+ validate_signal_ss(sig, ctx);
+
+ sig_err = ctx->uc_mcontext.gregs[REG_ERR];
+ sig_trapno = ctx->uc_mcontext.gregs[REG_TRAPNO];
+
+ unsigned short ss;
+ asm ("mov %%ss,%0" : "=r" (ss));
+
+ greg_t asm_ss = ctx->uc_mcontext.gregs[REG_CX];
+ if (asm_ss != sig_ss && sig == SIGTRAP) {
+ /* Sanity check failure. */
+ printf("[FAIL]\tSIGTRAP: ss = %hx, frame ss = %hx, ax = %llx\n",
+ ss, *ssptr(ctx), (unsigned long long)asm_ss);
+ nerrs++;
+ }
+
+ memcpy(&resulting_regs, &ctx->uc_mcontext.gregs, sizeof(gregset_t));
+ memcpy(&ctx->uc_mcontext.gregs, &initial_regs, sizeof(gregset_t));
+
+#ifdef __x86_64__
+ if (sig_corrupt_final_ss) {
+ if (ctx->uc_flags & UC_STRICT_RESTORE_SS) {
+ printf("[FAIL]\tUC_STRICT_RESTORE_SS was set inappropriately\n");
+ nerrs++;
+ } else {
+ /*
+ * DOSEMU transitions from 32-bit to 64-bit mode by
+ * adjusting sigcontext, and it requires that this work
+ * even if the saved SS is bogus.
+ */
+ printf("\tCorrupting SS on return to 64-bit mode\n");
+ *ssptr(ctx) = 0;
+ }
+ }
+#endif
+
+ sig_trapped = sig;
+}
+
+#ifdef __x86_64__
+/* Tests recovery if !UC_STRICT_RESTORE_SS */
+static void sigusr2(int sig, siginfo_t *info, void *ctx_void)
+{
+ ucontext_t *ctx = (ucontext_t*)ctx_void;
+
+ if (!(ctx->uc_flags & UC_STRICT_RESTORE_SS)) {
+ printf("[FAIL]\traise(2) didn't set UC_STRICT_RESTORE_SS\n");
+ nerrs++;
+ return; /* We can't do the rest. */
+ }
+
+ ctx->uc_flags &= ~UC_STRICT_RESTORE_SS;
+ *ssptr(ctx) = 0;
+
+ /* Return. The kernel should recover without sending another signal. */
+}
+
+static int test_nonstrict_ss(void)
+{
+ clearhandler(SIGUSR1);
+ clearhandler(SIGTRAP);
+ clearhandler(SIGSEGV);
+ clearhandler(SIGILL);
+ sethandler(SIGUSR2, sigusr2, 0);
+
+ nerrs = 0;
+
+ printf("[RUN]\tClear UC_STRICT_RESTORE_SS and corrupt SS\n");
+ raise(SIGUSR2);
+ if (!nerrs)
+ printf("[OK]\tIt worked\n");
+
+ return nerrs;
+}
+#endif
+
+/* Finds a usable code segment of the requested bitness. */
+int find_cs(int bitness)
+{
+ unsigned short my_cs;
+
+ asm ("mov %%cs,%0" : "=r" (my_cs));
+
+ if (cs_bitness(my_cs) == bitness)
+ return my_cs;
+ if (cs_bitness(my_cs + (2 << 3)) == bitness)
+ return my_cs + (2 << 3);
+ if (my_cs > (2<<3) && cs_bitness(my_cs - (2 << 3)) == bitness)
+ return my_cs - (2 << 3);
+ if (cs_bitness(code16_sel) == bitness)
+ return code16_sel;
+
+ printf("[WARN]\tCould not find %d-bit CS\n", bitness);
+ return -1;
+}
+
+static int test_valid_sigreturn(int cs_bits, bool use_16bit_ss, int force_ss)
+{
+ int cs = find_cs(cs_bits);
+ if (cs == -1) {
+ printf("[SKIP]\tCode segment unavailable for %d-bit CS, %d-bit SS\n",
+ cs_bits, use_16bit_ss ? 16 : 32);
+ return 0;
+ }
+
+ if (force_ss != -1) {
+ sig_ss = force_ss;
+ } else {
+ if (use_16bit_ss) {
+ if (!data16_sel) {
+ printf("[SKIP]\tData segment unavailable for %d-bit CS, 16-bit SS\n",
+ cs_bits);
+ return 0;
+ }
+ sig_ss = data16_sel;
+ } else {
+ asm volatile ("mov %%ss,%0" : "=r" (sig_ss));
+ }
+ }
+
+ sig_cs = cs;
+
+ printf("[RUN]\tValid sigreturn: %d-bit CS (%hx), %d-bit SS (%hx%s)\n",
+ cs_bits, sig_cs, use_16bit_ss ? 16 : 32, sig_ss,
+ (sig_ss & 4) ? "" : ", GDT");
+
+ raise(SIGUSR1);
+
+ nerrs = 0;
+
+ /*
+ * Check that each register had an acceptable value when the
+ * int3 trampoline was invoked.
+ */
+ for (int i = 0; i < NGREG; i++) {
+ greg_t req = requested_regs[i], res = resulting_regs[i];
+
+ if (i == REG_TRAPNO || i == REG_IP)
+ continue; /* don't care */
+
+ if (i == REG_SP) {
+ /*
+ * If we were using a 16-bit stack segment, then
+ * the kernel is a bit stuck: IRET only restores
+ * the low 16 bits of ESP/RSP if SS is 16-bit.
+ * The kernel uses a hack to restore bits 31:16,
+ * but that hack doesn't help with bits 63:32.
+ * On Intel CPUs, bits 63:32 end up zeroed, and, on
+ * AMD CPUs, they leak the high bits of the kernel
+ * espfix64 stack pointer. There's very little that
+ * the kernel can do about it.
+ *
+ * Similarly, if we are returning to a 32-bit context,
+ * the CPU will often lose the high 32 bits of RSP.
+ */
+
+ if (res == req)
+ continue;
+
+ if (cs_bits != 64 && ((res ^ req) & 0xFFFFFFFF) == 0) {
+ printf("[NOTE]\tSP: %llx -> %llx\n",
+ (unsigned long long)req,
+ (unsigned long long)res);
+ continue;
+ }
+
+ printf("[FAIL]\tSP mismatch: requested 0x%llx; got 0x%llx\n",
+ (unsigned long long)requested_regs[i],
+ (unsigned long long)resulting_regs[i]);
+ nerrs++;
+ continue;
+ }
+
+ bool ignore_reg = false;
+#if __i386__
+ if (i == REG_UESP)
+ ignore_reg = true;
+#else
+ if (i == REG_CSGSFS) {
+ struct selectors *req_sels =
+ (void *)&requested_regs[REG_CSGSFS];
+ struct selectors *res_sels =
+ (void *)&resulting_regs[REG_CSGSFS];
+ if (req_sels->cs != res_sels->cs) {
+ printf("[FAIL]\tCS mismatch: requested 0x%hx; got 0x%hx\n",
+ req_sels->cs, res_sels->cs);
+ nerrs++;
+ }
+
+ if (req_sels->ss != res_sels->ss) {
+ printf("[FAIL]\tSS mismatch: requested 0x%hx; got 0x%hx\n",
+ req_sels->ss, res_sels->ss);
+ nerrs++;
+ }
+
+ continue;
+ }
+#endif
+
+ /* Sanity check on the kernel */
+ if (i == REG_CX && req != res) {
+ printf("[FAIL]\tCX (saved SP) mismatch: requested 0x%llx; got 0x%llx\n",
+ (unsigned long long)req,
+ (unsigned long long)res);
+ nerrs++;
+ continue;
+ }
+
+ if (req != res && !ignore_reg) {
+ printf("[FAIL]\tReg %d mismatch: requested 0x%llx; got 0x%llx\n",
+ i, (unsigned long long)req,
+ (unsigned long long)res);
+ nerrs++;
+ }
+ }
+
+ if (nerrs == 0)
+ printf("[OK]\tall registers okay\n");
+
+ return nerrs;
+}
+
+static int test_bad_iret(int cs_bits, unsigned short ss, int force_cs)
+{
+ int cs = force_cs == -1 ? find_cs(cs_bits) : force_cs;
+ if (cs == -1)
+ return 0;
+
+ sig_cs = cs;
+ sig_ss = ss;
+
+ printf("[RUN]\t%d-bit CS (%hx), bogus SS (%hx)\n",
+ cs_bits, sig_cs, sig_ss);
+
+ sig_trapped = 0;
+ raise(SIGUSR1);
+ if (sig_trapped) {
+ char errdesc[32] = "";
+ if (sig_err) {
+ const char *src = (sig_err & 1) ? " EXT" : "";
+ const char *table;
+ if ((sig_err & 0x6) == 0x0)
+ table = "GDT";
+ else if ((sig_err & 0x6) == 0x4)
+ table = "LDT";
+ else if ((sig_err & 0x6) == 0x2)
+ table = "IDT";
+ else
+ table = "???";
+
+ sprintf(errdesc, "%s%s index %d, ",
+ table, src, sig_err >> 3);
+ }
+
+ char trapname[32];
+ if (sig_trapno == 13)
+ strcpy(trapname, "GP");
+ else if (sig_trapno == 11)
+ strcpy(trapname, "NP");
+ else if (sig_trapno == 12)
+ strcpy(trapname, "SS");
+ else if (sig_trapno == 32)
+ strcpy(trapname, "IRET"); /* X86_TRAP_IRET */
+ else
+ sprintf(trapname, "%d", sig_trapno);
+
+ printf("[OK]\tGot #%s(0x%lx) (i.e. %s%s)\n",
+ trapname, (unsigned long)sig_err,
+ errdesc, strsignal(sig_trapped));
+ return 0;
+ } else {
+ /*
+ * This also implicitly tests UC_STRICT_RESTORE_SS:
+ * We check that these signals set UC_STRICT_RESTORE_SS and,
+ * if UC_STRICT_RESTORE_SS doesn't cause strict behavior,
+ * then we won't get SIGSEGV.
+ */
+ printf("[FAIL]\tDid not get SIGSEGV\n");
+ return 1;
+ }
+}
+
+int main()
+{
+ int total_nerrs = 0;
+ unsigned short my_cs, my_ss;
+
+ asm volatile ("mov %%cs,%0" : "=r" (my_cs));
+ asm volatile ("mov %%ss,%0" : "=r" (my_ss));
+ setup_ldt();
+
+ stack_t stack = {
+ /* Our sigaltstack scratch space. */
+ .ss_sp = malloc(sizeof(char) * SIGSTKSZ),
+ .ss_size = SIGSTKSZ,
+ };
+ if (sigaltstack(&stack, NULL) != 0)
+ err(1, "sigaltstack");
+
+ sethandler(SIGUSR1, sigusr1, 0);
+ sethandler(SIGTRAP, sigtrap, SA_ONSTACK);
+
+ /* Easy cases: return to a 32-bit SS in each possible CS bitness. */
+ total_nerrs += test_valid_sigreturn(64, false, -1);
+ total_nerrs += test_valid_sigreturn(32, false, -1);
+ total_nerrs += test_valid_sigreturn(16, false, -1);
+
+ /*
+ * Test easy espfix cases: return to a 16-bit LDT SS in each possible
+ * CS bitness. NB: with a long mode CS, the SS bitness is irrelevant.
+ *
+ * This catches the original missing-espfix-on-64-bit-kernels issue
+ * as well as CVE-2014-8134.
+ */
+ total_nerrs += test_valid_sigreturn(64, true, -1);
+ total_nerrs += test_valid_sigreturn(32, true, -1);
+ total_nerrs += test_valid_sigreturn(16, true, -1);
+
+ if (gdt_data16_idx) {
+ /*
+ * For performance reasons, Linux skips espfix if SS points
+ * to the GDT. If we were able to allocate a 16-bit SS in
+ * the GDT, see if it leaks parts of the kernel stack pointer.
+ *
+ * This tests for CVE-2014-8133.
+ */
+ total_nerrs += test_valid_sigreturn(64, true,
+ GDT3(gdt_data16_idx));
+ total_nerrs += test_valid_sigreturn(32, true,
+ GDT3(gdt_data16_idx));
+ total_nerrs += test_valid_sigreturn(16, true,
+ GDT3(gdt_data16_idx));
+ }
+
+#ifdef __x86_64__
+ /* Nasty ABI case: check SS corruption handling. */
+ sig_corrupt_final_ss = 1;
+ total_nerrs += test_valid_sigreturn(32, false, -1);
+ total_nerrs += test_valid_sigreturn(32, true, -1);
+ sig_corrupt_final_ss = 0;
+#endif
+
+ /*
+ * We're done testing valid sigreturn cases. Now we test states
+ * for which sigreturn itself will succeed but the subsequent
+ * entry to user mode will fail.
+ *
+ * Depending on the failure mode and the kernel bitness, these
+ * entry failures can generate SIGSEGV, SIGBUS, or SIGILL.
+ */
+ clearhandler(SIGTRAP);
+ sethandler(SIGSEGV, sigtrap, SA_ONSTACK);
+ sethandler(SIGBUS, sigtrap, SA_ONSTACK);
+ sethandler(SIGILL, sigtrap, SA_ONSTACK); /* 32-bit kernels do this */
+
+ /* Easy failures: invalid SS, resulting in #GP(0) */
+ test_bad_iret(64, ldt_nonexistent_sel, -1);
+ test_bad_iret(32, ldt_nonexistent_sel, -1);
+ test_bad_iret(16, ldt_nonexistent_sel, -1);
+
+ /* These fail because SS isn't a data segment, resulting in #GP(SS) */
+ test_bad_iret(64, my_cs, -1);
+ test_bad_iret(32, my_cs, -1);
+ test_bad_iret(16, my_cs, -1);
+
+ /* Try to return to a not-present code segment, triggering #NP(SS). */
+ test_bad_iret(32, my_ss, npcode32_sel);
+
+ /*
+ * Try to return to a not-present but otherwise valid data segment.
+ * This will cause IRET to fail with #SS on the espfix stack. This
+ * exercises CVE-2014-9322.
+ *
+ * Note that, if espfix is enabled, 64-bit Linux will lose track
+ * of the actual cause of failure and report #GP(0) instead.
+ * This would be very difficult for Linux to avoid, because
+ * espfix64 causes IRET failures to be promoted to #DF, so the
+ * original exception frame is never pushed onto the stack.
+ */
+ test_bad_iret(32, npdata32_sel, -1);
+
+ /*
+ * Try to return to a not-present but otherwise valid data
+ * segment without invoking espfix. Newer kernels don't allow
+ * this to happen in the first place. On older kernels, though,
+ * this can trigger CVE-2014-9322.
+ */
+ if (gdt_npdata32_idx)
+ test_bad_iret(32, GDT3(gdt_npdata32_idx), -1);
+
+#ifdef __x86_64__
+ total_nerrs += test_nonstrict_ss();
+#endif
+
+ free(stack.ss_sp);
+ return total_nerrs ? 1 : 0;
+}
diff --git a/tools/testing/selftests/x86/single_step_syscall.c b/tools/testing/selftests/x86/single_step_syscall.c
new file mode 100644
index 000000000..9a30f443e
--- /dev/null
+++ b/tools/testing/selftests/x86/single_step_syscall.c
@@ -0,0 +1,242 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * single_step_syscall.c - single-steps various x86 syscalls
+ * Copyright (c) 2014-2015 Andrew Lutomirski
+ *
+ * This is a very simple series of tests that makes system calls with
+ * the TF flag set. This exercises some nasty kernel code in the
+ * SYSENTER case: SYSENTER does not clear TF, so SYSENTER with TF set
+ * immediately issues #DB from CPL 0. This requires special handling in
+ * the kernel.
+ */
+
+#define _GNU_SOURCE
+
+#include <sys/time.h>
+#include <time.h>
+#include <stdlib.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <inttypes.h>
+#include <sys/mman.h>
+#include <sys/signal.h>
+#include <sys/ucontext.h>
+#include <asm/ldt.h>
+#include <err.h>
+#include <setjmp.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include <sys/ptrace.h>
+#include <sys/user.h>
+
+#include "helpers.h"
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static void clearhandler(int sig)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_handler = SIG_DFL;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static volatile sig_atomic_t sig_traps, sig_eflags;
+sigjmp_buf jmpbuf;
+
+#ifdef __x86_64__
+# define REG_IP REG_RIP
+# define WIDTH "q"
+# define INT80_CLOBBERS "r8", "r9", "r10", "r11"
+#else
+# define REG_IP REG_EIP
+# define WIDTH "l"
+# define INT80_CLOBBERS
+#endif
+
+static void sigtrap(int sig, siginfo_t *info, void *ctx_void)
+{
+ ucontext_t *ctx = (ucontext_t*)ctx_void;
+
+ if (get_eflags() & X86_EFLAGS_TF) {
+ set_eflags(get_eflags() & ~X86_EFLAGS_TF);
+ printf("[WARN]\tSIGTRAP handler had TF set\n");
+ _exit(1);
+ }
+
+ sig_traps++;
+
+ if (sig_traps == 10000 || sig_traps == 10001) {
+ printf("[WARN]\tHit %d SIGTRAPs with si_addr 0x%lx, ip 0x%lx\n",
+ (int)sig_traps,
+ (unsigned long)info->si_addr,
+ (unsigned long)ctx->uc_mcontext.gregs[REG_IP]);
+ }
+}
+
+static char const * const signames[] = {
+ [SIGSEGV] = "SIGSEGV",
+ [SIGBUS] = "SIBGUS",
+ [SIGTRAP] = "SIGTRAP",
+ [SIGILL] = "SIGILL",
+};
+
+static void print_and_longjmp(int sig, siginfo_t *si, void *ctx_void)
+{
+ ucontext_t *ctx = ctx_void;
+
+ printf("\tGot %s with RIP=%lx, TF=%ld\n", signames[sig],
+ (unsigned long)ctx->uc_mcontext.gregs[REG_IP],
+ (unsigned long)ctx->uc_mcontext.gregs[REG_EFL] & X86_EFLAGS_TF);
+
+ sig_eflags = (unsigned long)ctx->uc_mcontext.gregs[REG_EFL];
+ siglongjmp(jmpbuf, 1);
+}
+
+static void check_result(void)
+{
+ unsigned long new_eflags = get_eflags();
+ set_eflags(new_eflags & ~X86_EFLAGS_TF);
+
+ if (!sig_traps) {
+ printf("[FAIL]\tNo SIGTRAP\n");
+ exit(1);
+ }
+
+ if (!(new_eflags & X86_EFLAGS_TF)) {
+ printf("[FAIL]\tTF was cleared\n");
+ exit(1);
+ }
+
+ printf("[OK]\tSurvived with TF set and %d traps\n", (int)sig_traps);
+ sig_traps = 0;
+}
+
+static void fast_syscall_no_tf(void)
+{
+ sig_traps = 0;
+ printf("[RUN]\tFast syscall with TF cleared\n");
+ fflush(stdout); /* Force a syscall */
+ if (get_eflags() & X86_EFLAGS_TF) {
+ printf("[FAIL]\tTF is now set\n");
+ exit(1);
+ }
+ if (sig_traps) {
+ printf("[FAIL]\tGot SIGTRAP\n");
+ exit(1);
+ }
+ printf("[OK]\tNothing unexpected happened\n");
+}
+
+int main()
+{
+#ifdef CAN_BUILD_32
+ int tmp;
+#endif
+
+ sethandler(SIGTRAP, sigtrap, 0);
+
+ printf("[RUN]\tSet TF and check nop\n");
+ set_eflags(get_eflags() | X86_EFLAGS_TF);
+ asm volatile ("nop");
+ check_result();
+
+#ifdef __x86_64__
+ printf("[RUN]\tSet TF and check syscall-less opportunistic sysret\n");
+ set_eflags(get_eflags() | X86_EFLAGS_TF);
+ extern unsigned char post_nop[];
+ asm volatile ("pushf" WIDTH "\n\t"
+ "pop" WIDTH " %%r11\n\t"
+ "nop\n\t"
+ "post_nop:"
+ : : "c" (post_nop) : "r11");
+ check_result();
+#endif
+#ifdef CAN_BUILD_32
+ printf("[RUN]\tSet TF and check int80\n");
+ set_eflags(get_eflags() | X86_EFLAGS_TF);
+ asm volatile ("int $0x80" : "=a" (tmp) : "a" (SYS_getpid)
+ : INT80_CLOBBERS);
+ check_result();
+#endif
+
+ /*
+ * This test is particularly interesting if fast syscalls use
+ * SYSENTER: it triggers a nasty design flaw in SYSENTER.
+ * Specifically, SYSENTER does not clear TF, so either SYSENTER
+ * or the next instruction traps at CPL0. (Of course, Intel
+ * mostly forgot to document exactly what happens here.) So we
+ * get a CPL0 fault with usergs (on 64-bit kernels) and possibly
+ * no stack. The only sane way the kernel can possibly handle
+ * it is to clear TF on return from the #DB handler, but this
+ * happens way too early to set TF in the saved pt_regs, so the
+ * kernel has to do something clever to avoid losing track of
+ * the TF bit.
+ *
+ * Needless to say, we've had bugs in this area.
+ */
+ syscall(SYS_getpid); /* Force symbol binding without TF set. */
+ printf("[RUN]\tSet TF and check a fast syscall\n");
+ set_eflags(get_eflags() | X86_EFLAGS_TF);
+ syscall(SYS_getpid);
+ check_result();
+
+ /* Now make sure that another fast syscall doesn't set TF again. */
+ fast_syscall_no_tf();
+
+ /*
+ * And do a forced SYSENTER to make sure that this works even if
+ * fast syscalls don't use SYSENTER.
+ *
+ * Invoking SYSENTER directly breaks all the rules. Just handle
+ * the SIGSEGV.
+ */
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ unsigned long nr = SYS_getpid;
+ printf("[RUN]\tSet TF and check SYSENTER\n");
+ stack_t stack = {
+ .ss_sp = malloc(sizeof(char) * SIGSTKSZ),
+ .ss_size = SIGSTKSZ,
+ };
+ if (sigaltstack(&stack, NULL) != 0)
+ err(1, "sigaltstack");
+ sethandler(SIGSEGV, print_and_longjmp,
+ SA_RESETHAND | SA_ONSTACK);
+ sethandler(SIGILL, print_and_longjmp, SA_RESETHAND);
+ set_eflags(get_eflags() | X86_EFLAGS_TF);
+ free(stack.ss_sp);
+ /* Clear EBP first to make sure we segfault cleanly. */
+ asm volatile ("xorl %%ebp, %%ebp; SYSENTER" : "+a" (nr) :: "flags", "rcx"
+#ifdef __x86_64__
+ , "r11"
+#endif
+ );
+
+ /* We're unreachable here. SYSENTER forgets RIP. */
+ }
+ clearhandler(SIGSEGV);
+ clearhandler(SIGILL);
+ if (!(sig_eflags & X86_EFLAGS_TF)) {
+ printf("[FAIL]\tTF was cleared\n");
+ exit(1);
+ }
+
+ /* Now make sure that another fast syscall doesn't set TF again. */
+ fast_syscall_no_tf();
+
+ return 0;
+}
diff --git a/tools/testing/selftests/x86/syscall_arg_fault.c b/tools/testing/selftests/x86/syscall_arg_fault.c
new file mode 100644
index 000000000..461fa41a4
--- /dev/null
+++ b/tools/testing/selftests/x86/syscall_arg_fault.c
@@ -0,0 +1,236 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * syscall_arg_fault.c - tests faults 32-bit fast syscall stack args
+ * Copyright (c) 2015 Andrew Lutomirski
+ */
+
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/signal.h>
+#include <sys/ucontext.h>
+#include <err.h>
+#include <setjmp.h>
+#include <errno.h>
+
+#include "helpers.h"
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static volatile sig_atomic_t sig_traps;
+static sigjmp_buf jmpbuf;
+
+static volatile sig_atomic_t n_errs;
+
+#ifdef __x86_64__
+#define REG_AX REG_RAX
+#define REG_IP REG_RIP
+#else
+#define REG_AX REG_EAX
+#define REG_IP REG_EIP
+#endif
+
+static void sigsegv_or_sigbus(int sig, siginfo_t *info, void *ctx_void)
+{
+ ucontext_t *ctx = (ucontext_t*)ctx_void;
+ long ax = (long)ctx->uc_mcontext.gregs[REG_AX];
+
+ if (ax != -EFAULT && ax != -ENOSYS) {
+ printf("[FAIL]\tAX had the wrong value: 0x%lx\n",
+ (unsigned long)ax);
+ printf("\tIP = 0x%lx\n", (unsigned long)ctx->uc_mcontext.gregs[REG_IP]);
+ n_errs++;
+ } else {
+ printf("[OK]\tSeems okay\n");
+ }
+
+ siglongjmp(jmpbuf, 1);
+}
+
+static volatile sig_atomic_t sigtrap_consecutive_syscalls;
+
+static void sigtrap(int sig, siginfo_t *info, void *ctx_void)
+{
+ /*
+ * KVM has some bugs that can cause us to stop making progress.
+ * detect them and complain, but don't infinite loop or fail the
+ * test.
+ */
+
+ ucontext_t *ctx = (ucontext_t*)ctx_void;
+ unsigned short *ip = (unsigned short *)ctx->uc_mcontext.gregs[REG_IP];
+
+ if (*ip == 0x340f || *ip == 0x050f) {
+ /* The trap was on SYSCALL or SYSENTER */
+ sigtrap_consecutive_syscalls++;
+ if (sigtrap_consecutive_syscalls > 3) {
+ printf("[WARN]\tGot stuck single-stepping -- you probably have a KVM bug\n");
+ siglongjmp(jmpbuf, 1);
+ }
+ } else {
+ sigtrap_consecutive_syscalls = 0;
+ }
+}
+
+static void sigill(int sig, siginfo_t *info, void *ctx_void)
+{
+ ucontext_t *ctx = (ucontext_t*)ctx_void;
+ unsigned short *ip = (unsigned short *)ctx->uc_mcontext.gregs[REG_IP];
+
+ if (*ip == 0x0b0f) {
+ /* one of the ud2 instructions faulted */
+ printf("[OK]\tSYSCALL returned normally\n");
+ } else {
+ printf("[SKIP]\tIllegal instruction\n");
+ }
+ siglongjmp(jmpbuf, 1);
+}
+
+int main()
+{
+ stack_t stack = {
+ /* Our sigaltstack scratch space. */
+ .ss_sp = malloc(sizeof(char) * SIGSTKSZ),
+ .ss_size = SIGSTKSZ,
+ };
+ if (sigaltstack(&stack, NULL) != 0)
+ err(1, "sigaltstack");
+
+ sethandler(SIGSEGV, sigsegv_or_sigbus, SA_ONSTACK);
+ /*
+ * The actual exception can vary. On Atom CPUs, we get #SS
+ * instead of #PF when the vDSO fails to access the stack when
+ * ESP is too close to 2^32, and #SS causes SIGBUS.
+ */
+ sethandler(SIGBUS, sigsegv_or_sigbus, SA_ONSTACK);
+ sethandler(SIGILL, sigill, SA_ONSTACK);
+
+ /*
+ * Exercise another nasty special case. The 32-bit SYSCALL
+ * and SYSENTER instructions (even in compat mode) each
+ * clobber one register. A Linux system call has a syscall
+ * number and six arguments, and the user stack pointer
+ * needs to live in some register on return. That means
+ * that we need eight registers, but SYSCALL and SYSENTER
+ * only preserve seven registers. As a result, one argument
+ * ends up on the stack. The stack is user memory, which
+ * means that the kernel can fail to read it.
+ *
+ * The 32-bit fast system calls don't have a defined ABI:
+ * we're supposed to invoke them through the vDSO. So we'll
+ * fudge it: we set all regs to invalid pointer values and
+ * invoke the entry instruction. The return will fail no
+ * matter what, and we completely lose our program state,
+ * but we can fix it up with a signal handler.
+ */
+
+ printf("[RUN]\tSYSENTER with invalid state\n");
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ asm volatile (
+ "movl $-1, %%eax\n\t"
+ "movl $-1, %%ebx\n\t"
+ "movl $-1, %%ecx\n\t"
+ "movl $-1, %%edx\n\t"
+ "movl $-1, %%esi\n\t"
+ "movl $-1, %%edi\n\t"
+ "movl $-1, %%ebp\n\t"
+ "movl $-1, %%esp\n\t"
+ "sysenter"
+ : : : "memory", "flags");
+ }
+
+ printf("[RUN]\tSYSCALL with invalid state\n");
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ asm volatile (
+ "movl $-1, %%eax\n\t"
+ "movl $-1, %%ebx\n\t"
+ "movl $-1, %%ecx\n\t"
+ "movl $-1, %%edx\n\t"
+ "movl $-1, %%esi\n\t"
+ "movl $-1, %%edi\n\t"
+ "movl $-1, %%ebp\n\t"
+ "movl $-1, %%esp\n\t"
+ "syscall\n\t"
+ "ud2" /* make sure we recover cleanly */
+ : : : "memory", "flags");
+ }
+
+ printf("[RUN]\tSYSENTER with TF and invalid state\n");
+ sethandler(SIGTRAP, sigtrap, SA_ONSTACK);
+
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ sigtrap_consecutive_syscalls = 0;
+ set_eflags(get_eflags() | X86_EFLAGS_TF);
+ asm volatile (
+ "movl $-1, %%eax\n\t"
+ "movl $-1, %%ebx\n\t"
+ "movl $-1, %%ecx\n\t"
+ "movl $-1, %%edx\n\t"
+ "movl $-1, %%esi\n\t"
+ "movl $-1, %%edi\n\t"
+ "movl $-1, %%ebp\n\t"
+ "movl $-1, %%esp\n\t"
+ "sysenter"
+ : : : "memory", "flags");
+ }
+ set_eflags(get_eflags() & ~X86_EFLAGS_TF);
+
+ printf("[RUN]\tSYSCALL with TF and invalid state\n");
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ sigtrap_consecutive_syscalls = 0;
+ set_eflags(get_eflags() | X86_EFLAGS_TF);
+ asm volatile (
+ "movl $-1, %%eax\n\t"
+ "movl $-1, %%ebx\n\t"
+ "movl $-1, %%ecx\n\t"
+ "movl $-1, %%edx\n\t"
+ "movl $-1, %%esi\n\t"
+ "movl $-1, %%edi\n\t"
+ "movl $-1, %%ebp\n\t"
+ "movl $-1, %%esp\n\t"
+ "syscall\n\t"
+ "ud2" /* make sure we recover cleanly */
+ : : : "memory", "flags");
+ }
+ set_eflags(get_eflags() & ~X86_EFLAGS_TF);
+
+#ifdef __x86_64__
+ printf("[RUN]\tSYSENTER with TF, invalid state, and GSBASE < 0\n");
+
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ sigtrap_consecutive_syscalls = 0;
+
+ asm volatile ("wrgsbase %%rax\n\t"
+ :: "a" (0xffffffffffff0000UL));
+
+ set_eflags(get_eflags() | X86_EFLAGS_TF);
+ asm volatile (
+ "movl $-1, %%eax\n\t"
+ "movl $-1, %%ebx\n\t"
+ "movl $-1, %%ecx\n\t"
+ "movl $-1, %%edx\n\t"
+ "movl $-1, %%esi\n\t"
+ "movl $-1, %%edi\n\t"
+ "movl $-1, %%ebp\n\t"
+ "movl $-1, %%esp\n\t"
+ "sysenter"
+ : : : "memory", "flags");
+ }
+ set_eflags(get_eflags() & ~X86_EFLAGS_TF);
+#endif
+
+ free(stack.ss_sp);
+ return 0;
+}
diff --git a/tools/testing/selftests/x86/syscall_nt.c b/tools/testing/selftests/x86/syscall_nt.c
new file mode 100644
index 000000000..a108b80dd
--- /dev/null
+++ b/tools/testing/selftests/x86/syscall_nt.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * syscall_nt.c - checks syscalls with NT set
+ * Copyright (c) 2014-2015 Andrew Lutomirski
+ *
+ * Some obscure user-space code requires the ability to make system calls
+ * with FLAGS.NT set. Make sure it works.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <signal.h>
+#include <err.h>
+#include <sys/syscall.h>
+
+#include "helpers.h"
+
+static unsigned int nerrs;
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static void sigtrap(int sig, siginfo_t *si, void *ctx_void)
+{
+}
+
+static void do_it(unsigned long extraflags)
+{
+ unsigned long flags;
+
+ set_eflags(get_eflags() | extraflags);
+ syscall(SYS_getpid);
+ flags = get_eflags();
+ set_eflags(X86_EFLAGS_IF | X86_EFLAGS_FIXED);
+ if ((flags & extraflags) == extraflags) {
+ printf("[OK]\tThe syscall worked and flags are still set\n");
+ } else {
+ printf("[FAIL]\tThe syscall worked but flags were cleared (flags = 0x%lx but expected 0x%lx set)\n",
+ flags, extraflags);
+ nerrs++;
+ }
+}
+
+int main(void)
+{
+ printf("[RUN]\tSet NT and issue a syscall\n");
+ do_it(X86_EFLAGS_NT);
+
+ printf("[RUN]\tSet AC and issue a syscall\n");
+ do_it(X86_EFLAGS_AC);
+
+ printf("[RUN]\tSet NT|AC and issue a syscall\n");
+ do_it(X86_EFLAGS_NT | X86_EFLAGS_AC);
+
+ /*
+ * Now try it again with TF set -- TF forces returns via IRET in all
+ * cases except non-ptregs-using 64-bit full fast path syscalls.
+ */
+
+ sethandler(SIGTRAP, sigtrap, 0);
+
+ printf("[RUN]\tSet TF and issue a syscall\n");
+ do_it(X86_EFLAGS_TF);
+
+ printf("[RUN]\tSet NT|TF and issue a syscall\n");
+ do_it(X86_EFLAGS_NT | X86_EFLAGS_TF);
+
+ printf("[RUN]\tSet AC|TF and issue a syscall\n");
+ do_it(X86_EFLAGS_AC | X86_EFLAGS_TF);
+
+ printf("[RUN]\tSet NT|AC|TF and issue a syscall\n");
+ do_it(X86_EFLAGS_NT | X86_EFLAGS_AC | X86_EFLAGS_TF);
+
+ /*
+ * Now try DF. This is evil and it's plausible that we will crash
+ * glibc, but glibc would have to do something rather surprising
+ * for this to happen.
+ */
+ printf("[RUN]\tSet DF and issue a syscall\n");
+ do_it(X86_EFLAGS_DF);
+
+ printf("[RUN]\tSet TF|DF and issue a syscall\n");
+ do_it(X86_EFLAGS_TF | X86_EFLAGS_DF);
+
+ return nerrs == 0 ? 0 : 1;
+}
diff --git a/tools/testing/selftests/x86/syscall_numbering.c b/tools/testing/selftests/x86/syscall_numbering.c
new file mode 100644
index 000000000..991591718
--- /dev/null
+++ b/tools/testing/selftests/x86/syscall_numbering.c
@@ -0,0 +1,482 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * syscall_numbering.c - test calling the x86-64 kernel with various
+ * valid and invalid system call numbers.
+ *
+ * Copyright (c) 2018 Andrew Lutomirski
+ */
+
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <signal.h>
+#include <sysexits.h>
+
+#include <sys/ptrace.h>
+#include <sys/user.h>
+#include <sys/wait.h>
+#include <sys/mman.h>
+
+#include <linux/ptrace.h>
+
+/* Common system call numbers */
+#define SYS_READ 0
+#define SYS_WRITE 1
+#define SYS_GETPID 39
+/* x64-only system call numbers */
+#define X64_IOCTL 16
+#define X64_READV 19
+#define X64_WRITEV 20
+/* x32-only system call numbers (without X32_BIT) */
+#define X32_IOCTL 514
+#define X32_READV 515
+#define X32_WRITEV 516
+
+#define X32_BIT 0x40000000
+
+static int nullfd = -1; /* File descriptor for /dev/null */
+static bool with_x32; /* x32 supported on this kernel? */
+
+enum ptrace_pass {
+ PTP_NOTHING,
+ PTP_GETREGS,
+ PTP_WRITEBACK,
+ PTP_FUZZRET,
+ PTP_FUZZHIGH,
+ PTP_INTNUM,
+ PTP_DONE
+};
+
+static const char * const ptrace_pass_name[] =
+{
+ [PTP_NOTHING] = "just stop, no data read",
+ [PTP_GETREGS] = "only getregs",
+ [PTP_WRITEBACK] = "getregs, unmodified setregs",
+ [PTP_FUZZRET] = "modifying the default return",
+ [PTP_FUZZHIGH] = "clobbering the top 32 bits",
+ [PTP_INTNUM] = "sign-extending the syscall number",
+};
+
+/*
+ * Shared memory block between tracer and test
+ */
+struct shared {
+ unsigned int nerr; /* Total error count */
+ unsigned int indent; /* Message indentation level */
+ enum ptrace_pass ptrace_pass;
+ bool probing_syscall; /* In probe_syscall() */
+};
+static volatile struct shared *sh;
+
+static inline unsigned int offset(void)
+{
+ unsigned int level = sh ? sh->indent : 0;
+
+ return 8 + level * 4;
+}
+
+#define msg(lvl, fmt, ...) printf("%-*s" fmt, offset(), "[" #lvl "]", \
+ ## __VA_ARGS__)
+
+#define run(fmt, ...) msg(RUN, fmt, ## __VA_ARGS__)
+#define info(fmt, ...) msg(INFO, fmt, ## __VA_ARGS__)
+#define ok(fmt, ...) msg(OK, fmt, ## __VA_ARGS__)
+
+#define fail(fmt, ...) \
+ do { \
+ msg(FAIL, fmt, ## __VA_ARGS__); \
+ sh->nerr++; \
+ } while (0)
+
+#define crit(fmt, ...) \
+ do { \
+ sh->indent = 0; \
+ msg(FAIL, fmt, ## __VA_ARGS__); \
+ msg(SKIP, "Unable to run test\n"); \
+ exit(EX_OSERR); \
+ } while (0)
+
+/* Sentinel for ptrace-modified return value */
+#define MODIFIED_BY_PTRACE -9999
+
+/*
+ * Directly invokes the given syscall with nullfd as the first argument
+ * and the rest zero. Avoids involving glibc wrappers in case they ever
+ * end up intercepting some system calls for some reason, or modify
+ * the system call number itself.
+ */
+static long long probe_syscall(int msb, int lsb)
+{
+ register long long arg1 asm("rdi") = nullfd;
+ register long long arg2 asm("rsi") = 0;
+ register long long arg3 asm("rdx") = 0;
+ register long long arg4 asm("r10") = 0;
+ register long long arg5 asm("r8") = 0;
+ register long long arg6 asm("r9") = 0;
+ long long nr = ((long long)msb << 32) | (unsigned int)lsb;
+ long long ret;
+
+ /*
+ * We pass in an extra copy of the extended system call number
+ * in %rbx, so we can examine it from the ptrace handler without
+ * worrying about it being possibly modified. This is to test
+ * the validity of struct user regs.orig_rax a.k.a.
+ * struct pt_regs.orig_ax.
+ */
+ sh->probing_syscall = true;
+ asm volatile("syscall"
+ : "=a" (ret)
+ : "a" (nr), "b" (nr),
+ "r" (arg1), "r" (arg2), "r" (arg3),
+ "r" (arg4), "r" (arg5), "r" (arg6)
+ : "rcx", "r11", "memory", "cc");
+ sh->probing_syscall = false;
+
+ return ret;
+}
+
+static const char *syscall_str(int msb, int start, int end)
+{
+ static char buf[64];
+ const char * const type = (start & X32_BIT) ? "x32" : "x64";
+ int lsb = start;
+
+ /*
+ * Improve readability by stripping the x32 bit, but round
+ * toward zero so we don't display -1 as -1073741825.
+ */
+ if (lsb < 0)
+ lsb |= X32_BIT;
+ else
+ lsb &= ~X32_BIT;
+
+ if (start == end)
+ snprintf(buf, sizeof buf, "%s syscall %d:%d",
+ type, msb, lsb);
+ else
+ snprintf(buf, sizeof buf, "%s syscalls %d:%d..%d",
+ type, msb, lsb, lsb + (end-start));
+
+ return buf;
+}
+
+static unsigned int _check_for(int msb, int start, int end, long long expect,
+ const char *expect_str)
+{
+ unsigned int err = 0;
+
+ sh->indent++;
+ if (start != end)
+ sh->indent++;
+
+ for (int nr = start; nr <= end; nr++) {
+ long long ret = probe_syscall(msb, nr);
+
+ if (ret != expect) {
+ fail("%s returned %lld, but it should have returned %s\n",
+ syscall_str(msb, nr, nr),
+ ret, expect_str);
+ err++;
+ }
+ }
+
+ if (start != end)
+ sh->indent--;
+
+ if (err) {
+ if (start != end)
+ fail("%s had %u failure%s\n",
+ syscall_str(msb, start, end),
+ err, err == 1 ? "s" : "");
+ } else {
+ ok("%s returned %s as expected\n",
+ syscall_str(msb, start, end), expect_str);
+ }
+
+ sh->indent--;
+
+ return err;
+}
+
+#define check_for(msb,start,end,expect) \
+ _check_for(msb,start,end,expect,#expect)
+
+static bool check_zero(int msb, int nr)
+{
+ return check_for(msb, nr, nr, 0);
+}
+
+static bool check_enosys(int msb, int nr)
+{
+ return check_for(msb, nr, nr, -ENOSYS);
+}
+
+/*
+ * Anyone diagnosing a failure will want to know whether the kernel
+ * supports x32. Tell them. This can also be used to conditionalize
+ * tests based on existence or nonexistence of x32.
+ */
+static bool test_x32(void)
+{
+ long long ret;
+ pid_t mypid = getpid();
+
+ run("Checking for x32 by calling x32 getpid()\n");
+ ret = probe_syscall(0, SYS_GETPID | X32_BIT);
+
+ sh->indent++;
+ if (ret == mypid) {
+ info("x32 is supported\n");
+ with_x32 = true;
+ } else if (ret == -ENOSYS) {
+ info("x32 is not supported\n");
+ with_x32 = false;
+ } else {
+ fail("x32 getpid() returned %lld, but it should have returned either %lld or -ENOSYS\n", ret, (long long)mypid);
+ with_x32 = false;
+ }
+ sh->indent--;
+ return with_x32;
+}
+
+static void test_syscalls_common(int msb)
+{
+ enum ptrace_pass pass = sh->ptrace_pass;
+
+ run("Checking some common syscalls as 64 bit\n");
+ check_zero(msb, SYS_READ);
+ check_zero(msb, SYS_WRITE);
+
+ run("Checking some 64-bit only syscalls as 64 bit\n");
+ check_zero(msb, X64_READV);
+ check_zero(msb, X64_WRITEV);
+
+ run("Checking out of range system calls\n");
+ check_for(msb, -64, -2, -ENOSYS);
+ if (pass >= PTP_FUZZRET)
+ check_for(msb, -1, -1, MODIFIED_BY_PTRACE);
+ else
+ check_for(msb, -1, -1, -ENOSYS);
+ check_for(msb, X32_BIT-64, X32_BIT-1, -ENOSYS);
+ check_for(msb, -64-X32_BIT, -1-X32_BIT, -ENOSYS);
+ check_for(msb, INT_MAX-64, INT_MAX-1, -ENOSYS);
+}
+
+static void test_syscalls_with_x32(int msb)
+{
+ /*
+ * Syscalls 512-547 are "x32" syscalls. They are
+ * intended to be called with the x32 (0x40000000) bit
+ * set. Calling them without the x32 bit set is
+ * nonsense and should not work.
+ */
+ run("Checking x32 syscalls as 64 bit\n");
+ check_for(msb, 512, 547, -ENOSYS);
+
+ run("Checking some common syscalls as x32\n");
+ check_zero(msb, SYS_READ | X32_BIT);
+ check_zero(msb, SYS_WRITE | X32_BIT);
+
+ run("Checking some x32 syscalls as x32\n");
+ check_zero(msb, X32_READV | X32_BIT);
+ check_zero(msb, X32_WRITEV | X32_BIT);
+
+ run("Checking some 64-bit syscalls as x32\n");
+ check_enosys(msb, X64_IOCTL | X32_BIT);
+ check_enosys(msb, X64_READV | X32_BIT);
+ check_enosys(msb, X64_WRITEV | X32_BIT);
+}
+
+static void test_syscalls_without_x32(int msb)
+{
+ run("Checking for absence of x32 system calls\n");
+ check_for(msb, 0 | X32_BIT, 999 | X32_BIT, -ENOSYS);
+}
+
+static void test_syscall_numbering(void)
+{
+ static const int msbs[] = {
+ 0, 1, -1, X32_BIT-1, X32_BIT, X32_BIT-1, -X32_BIT, INT_MAX,
+ INT_MIN, INT_MIN+1
+ };
+
+ sh->indent++;
+
+ /*
+ * The MSB is supposed to be ignored, so we loop over a few
+ * to test that out.
+ */
+ for (size_t i = 0; i < sizeof(msbs)/sizeof(msbs[0]); i++) {
+ int msb = msbs[i];
+ run("Checking system calls with msb = %d (0x%x)\n",
+ msb, msb);
+
+ sh->indent++;
+
+ test_syscalls_common(msb);
+ if (with_x32)
+ test_syscalls_with_x32(msb);
+ else
+ test_syscalls_without_x32(msb);
+
+ sh->indent--;
+ }
+
+ sh->indent--;
+}
+
+static void syscall_numbering_tracee(void)
+{
+ enum ptrace_pass pass;
+
+ if (ptrace(PTRACE_TRACEME, 0, 0, 0)) {
+ crit("Failed to request tracing\n");
+ return;
+ }
+ raise(SIGSTOP);
+
+ for (sh->ptrace_pass = pass = PTP_NOTHING; pass < PTP_DONE;
+ sh->ptrace_pass = ++pass) {
+ run("Running tests under ptrace: %s\n", ptrace_pass_name[pass]);
+ test_syscall_numbering();
+ }
+}
+
+static void mess_with_syscall(pid_t testpid, enum ptrace_pass pass)
+{
+ struct user_regs_struct regs;
+
+ sh->probing_syscall = false; /* Do this on entry only */
+
+ /* For these, don't even getregs */
+ if (pass == PTP_NOTHING || pass == PTP_DONE)
+ return;
+
+ ptrace(PTRACE_GETREGS, testpid, NULL, &regs);
+
+ if (regs.orig_rax != regs.rbx) {
+ fail("orig_rax %#llx doesn't match syscall number %#llx\n",
+ (unsigned long long)regs.orig_rax,
+ (unsigned long long)regs.rbx);
+ }
+
+ switch (pass) {
+ case PTP_GETREGS:
+ /* Just read, no writeback */
+ return;
+ case PTP_WRITEBACK:
+ /* Write back the same register state verbatim */
+ break;
+ case PTP_FUZZRET:
+ regs.rax = MODIFIED_BY_PTRACE;
+ break;
+ case PTP_FUZZHIGH:
+ regs.rax = MODIFIED_BY_PTRACE;
+ regs.orig_rax = regs.orig_rax | 0xffffffff00000000ULL;
+ break;
+ case PTP_INTNUM:
+ regs.rax = MODIFIED_BY_PTRACE;
+ regs.orig_rax = (int)regs.orig_rax;
+ break;
+ default:
+ crit("invalid ptrace_pass\n");
+ break;
+ }
+
+ ptrace(PTRACE_SETREGS, testpid, NULL, &regs);
+}
+
+static void syscall_numbering_tracer(pid_t testpid)
+{
+ int wstatus;
+
+ do {
+ pid_t wpid = waitpid(testpid, &wstatus, 0);
+ if (wpid < 0 && errno != EINTR)
+ break;
+ if (wpid != testpid)
+ continue;
+ if (!WIFSTOPPED(wstatus))
+ break; /* Thread exited? */
+
+ if (sh->probing_syscall && WSTOPSIG(wstatus) == SIGTRAP)
+ mess_with_syscall(testpid, sh->ptrace_pass);
+ } while (sh->ptrace_pass != PTP_DONE &&
+ !ptrace(PTRACE_SYSCALL, testpid, NULL, NULL));
+
+ ptrace(PTRACE_DETACH, testpid, NULL, NULL);
+
+ /* Wait for the child process to terminate */
+ while (waitpid(testpid, &wstatus, 0) != testpid || !WIFEXITED(wstatus))
+ /* wait some more */;
+}
+
+static void test_traced_syscall_numbering(void)
+{
+ pid_t testpid;
+
+ /* Launch the test thread; this thread continues as the tracer thread */
+ testpid = fork();
+
+ if (testpid < 0) {
+ crit("Unable to launch tracer process\n");
+ } else if (testpid == 0) {
+ syscall_numbering_tracee();
+ _exit(0);
+ } else {
+ syscall_numbering_tracer(testpid);
+ }
+}
+
+int main(void)
+{
+ unsigned int nerr;
+
+ /*
+ * It is quite likely to get a segfault on a failure, so make
+ * sure the message gets out by setting stdout to nonbuffered.
+ */
+ setvbuf(stdout, NULL, _IONBF, 0);
+
+ /*
+ * Harmless file descriptor to work on...
+ */
+ nullfd = open("/dev/null", O_RDWR);
+ if (nullfd < 0) {
+ crit("Unable to open /dev/null: %s\n", strerror(errno));
+ }
+
+ /*
+ * Set up a block of shared memory...
+ */
+ sh = mmap(NULL, sysconf(_SC_PAGE_SIZE), PROT_READ|PROT_WRITE,
+ MAP_ANONYMOUS|MAP_SHARED, 0, 0);
+ if (sh == MAP_FAILED) {
+ crit("Unable to allocated shared memory block: %s\n",
+ strerror(errno));
+ }
+
+ with_x32 = test_x32();
+
+ run("Running tests without ptrace...\n");
+ test_syscall_numbering();
+
+ test_traced_syscall_numbering();
+
+ nerr = sh->nerr;
+ if (!nerr) {
+ ok("All system calls succeeded or failed as expected\n");
+ return 0;
+ } else {
+ fail("A total of %u system call%s had incorrect behavior\n",
+ nerr, nerr != 1 ? "s" : "");
+ return 1;
+ }
+}
diff --git a/tools/testing/selftests/x86/sysret_rip.c b/tools/testing/selftests/x86/sysret_rip.c
new file mode 100644
index 000000000..84d74be1d
--- /dev/null
+++ b/tools/testing/selftests/x86/sysret_rip.c
@@ -0,0 +1,187 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sigreturn.c - tests that x86 avoids Intel SYSRET pitfalls
+ * Copyright (c) 2014-2016 Andrew Lutomirski
+ */
+
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <inttypes.h>
+#include <sys/signal.h>
+#include <sys/ucontext.h>
+#include <sys/syscall.h>
+#include <err.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include <setjmp.h>
+#include <sys/user.h>
+#include <sys/mman.h>
+#include <assert.h>
+
+
+asm (
+ ".pushsection \".text\", \"ax\"\n\t"
+ ".balign 4096\n\t"
+ "test_page: .globl test_page\n\t"
+ ".fill 4094,1,0xcc\n\t"
+ "test_syscall_insn:\n\t"
+ "syscall\n\t"
+ ".ifne . - test_page - 4096\n\t"
+ ".error \"test page is not one page long\"\n\t"
+ ".endif\n\t"
+ ".popsection"
+ );
+
+extern const char test_page[];
+static void const *current_test_page_addr = test_page;
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static void clearhandler(int sig)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_handler = SIG_DFL;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+/* State used by our signal handlers. */
+static gregset_t initial_regs;
+
+static volatile unsigned long rip;
+
+static void sigsegv_for_sigreturn_test(int sig, siginfo_t *info, void *ctx_void)
+{
+ ucontext_t *ctx = (ucontext_t*)ctx_void;
+
+ if (rip != ctx->uc_mcontext.gregs[REG_RIP]) {
+ printf("[FAIL]\tRequested RIP=0x%lx but got RIP=0x%lx\n",
+ rip, (unsigned long)ctx->uc_mcontext.gregs[REG_RIP]);
+ fflush(stdout);
+ _exit(1);
+ }
+
+ memcpy(&ctx->uc_mcontext.gregs, &initial_regs, sizeof(gregset_t));
+
+ printf("[OK]\tGot SIGSEGV at RIP=0x%lx\n", rip);
+}
+
+static void sigusr1(int sig, siginfo_t *info, void *ctx_void)
+{
+ ucontext_t *ctx = (ucontext_t*)ctx_void;
+
+ memcpy(&initial_regs, &ctx->uc_mcontext.gregs, sizeof(gregset_t));
+
+ /* Set IP and CX to match so that SYSRET can happen. */
+ ctx->uc_mcontext.gregs[REG_RIP] = rip;
+ ctx->uc_mcontext.gregs[REG_RCX] = rip;
+
+ /* R11 and EFLAGS should already match. */
+ assert(ctx->uc_mcontext.gregs[REG_EFL] ==
+ ctx->uc_mcontext.gregs[REG_R11]);
+
+ sethandler(SIGSEGV, sigsegv_for_sigreturn_test, SA_RESETHAND);
+
+ return;
+}
+
+static void test_sigreturn_to(unsigned long ip)
+{
+ rip = ip;
+ printf("[RUN]\tsigreturn to 0x%lx\n", ip);
+ raise(SIGUSR1);
+}
+
+static jmp_buf jmpbuf;
+
+static void sigsegv_for_fallthrough(int sig, siginfo_t *info, void *ctx_void)
+{
+ ucontext_t *ctx = (ucontext_t*)ctx_void;
+
+ if (rip != ctx->uc_mcontext.gregs[REG_RIP]) {
+ printf("[FAIL]\tExpected SIGSEGV at 0x%lx but got RIP=0x%lx\n",
+ rip, (unsigned long)ctx->uc_mcontext.gregs[REG_RIP]);
+ fflush(stdout);
+ _exit(1);
+ }
+
+ siglongjmp(jmpbuf, 1);
+}
+
+static void test_syscall_fallthrough_to(unsigned long ip)
+{
+ void *new_address = (void *)(ip - 4096);
+ void *ret;
+
+ printf("[RUN]\tTrying a SYSCALL that falls through to 0x%lx\n", ip);
+
+ ret = mremap((void *)current_test_page_addr, 4096, 4096,
+ MREMAP_MAYMOVE | MREMAP_FIXED, new_address);
+ if (ret == MAP_FAILED) {
+ if (ip <= (1UL << 47) - PAGE_SIZE) {
+ err(1, "mremap to %p", new_address);
+ } else {
+ printf("[OK]\tmremap to %p failed\n", new_address);
+ return;
+ }
+ }
+
+ if (ret != new_address)
+ errx(1, "mremap malfunctioned: asked for %p but got %p\n",
+ new_address, ret);
+
+ current_test_page_addr = new_address;
+ rip = ip;
+
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ asm volatile ("call *%[syscall_insn]" :: "a" (SYS_getpid),
+ [syscall_insn] "rm" (ip - 2));
+ errx(1, "[FAIL]\tSyscall trampoline returned");
+ }
+
+ printf("[OK]\tWe survived\n");
+}
+
+int main()
+{
+ /*
+ * When the kernel returns from a slow-path syscall, it will
+ * detect whether SYSRET is appropriate. If it incorrectly
+ * thinks that SYSRET is appropriate when RIP is noncanonical,
+ * it'll crash on Intel CPUs.
+ */
+ sethandler(SIGUSR1, sigusr1, 0);
+ for (int i = 47; i < 64; i++)
+ test_sigreturn_to(1UL<<i);
+
+ clearhandler(SIGUSR1);
+
+ sethandler(SIGSEGV, sigsegv_for_fallthrough, 0);
+
+ /* One extra test to check that we didn't screw up the mremap logic. */
+ test_syscall_fallthrough_to((1UL << 47) - 2*PAGE_SIZE);
+
+ /* These are the interesting cases. */
+ for (int i = 47; i < 64; i++) {
+ test_syscall_fallthrough_to((1UL<<i) - PAGE_SIZE);
+ test_syscall_fallthrough_to(1UL<<i);
+ }
+
+ return 0;
+}
diff --git a/tools/testing/selftests/x86/sysret_ss_attrs.c b/tools/testing/selftests/x86/sysret_ss_attrs.c
new file mode 100644
index 000000000..5f3d4fca4
--- /dev/null
+++ b/tools/testing/selftests/x86/sysret_ss_attrs.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sysret_ss_attrs.c - test that syscalls return valid hidden SS attributes
+ * Copyright (c) 2015 Andrew Lutomirski
+ *
+ * On AMD CPUs, SYSRET can return with a valid SS descriptor with with
+ * the hidden attributes set to an unusable state. Make sure the kernel
+ * doesn't let this happen.
+ */
+
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <err.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include <pthread.h>
+
+static void *threadproc(void *ctx)
+{
+ /*
+ * Do our best to cause sleeps on this CPU to exit the kernel and
+ * re-enter with SS = 0.
+ */
+ while (true)
+ ;
+
+ return NULL;
+}
+
+#ifdef __x86_64__
+extern unsigned long call32_from_64(void *stack, void (*function)(void));
+
+asm (".pushsection .text\n\t"
+ ".code32\n\t"
+ "test_ss:\n\t"
+ "pushl $0\n\t"
+ "popl %eax\n\t"
+ "ret\n\t"
+ ".code64");
+extern void test_ss(void);
+#endif
+
+int main()
+{
+ /*
+ * Start a busy-looping thread on the same CPU we're on.
+ * For simplicity, just stick everything to CPU 0. This will
+ * fail in some containers, but that's probably okay.
+ */
+ cpu_set_t cpuset;
+ CPU_ZERO(&cpuset);
+ CPU_SET(0, &cpuset);
+ if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
+ printf("[WARN]\tsched_setaffinity failed\n");
+
+ pthread_t thread;
+ if (pthread_create(&thread, 0, threadproc, 0) != 0)
+ err(1, "pthread_create");
+
+#ifdef __x86_64__
+ unsigned char *stack32 = mmap(NULL, 4096, PROT_READ | PROT_WRITE,
+ MAP_32BIT | MAP_ANONYMOUS | MAP_PRIVATE,
+ -1, 0);
+ if (stack32 == MAP_FAILED)
+ err(1, "mmap");
+#endif
+
+ printf("[RUN]\tSyscalls followed by SS validation\n");
+
+ for (int i = 0; i < 1000; i++) {
+ /*
+ * Go to sleep and return using sysret (if we're 64-bit
+ * or we're 32-bit on AMD on a 64-bit kernel). On AMD CPUs,
+ * SYSRET doesn't fix up the cached SS descriptor, so the
+ * kernel needs some kind of workaround to make sure that we
+ * end the system call with a valid stack segment. This
+ * can be a confusing failure because the SS *selector*
+ * is the same regardless.
+ */
+ usleep(2);
+
+#ifdef __x86_64__
+ /*
+ * On 32-bit, just doing a syscall through glibc is enough
+ * to cause a crash if our cached SS descriptor is invalid.
+ * On 64-bit, it's not, so try extra hard.
+ */
+ call32_from_64(stack32 + 4088, test_ss);
+#endif
+ }
+
+ printf("[OK]\tWe survived\n");
+
+#ifdef __x86_64__
+ munmap(stack32, 4096);
+#endif
+
+ return 0;
+}
diff --git a/tools/testing/selftests/x86/test_FCMOV.c b/tools/testing/selftests/x86/test_FCMOV.c
new file mode 100644
index 000000000..6b5036fbb
--- /dev/null
+++ b/tools/testing/selftests/x86/test_FCMOV.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0
+#undef _GNU_SOURCE
+#define _GNU_SOURCE 1
+#undef __USE_GNU
+#define __USE_GNU 1
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/select.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+
+#define TEST(insn) \
+long double __attribute__((noinline)) insn(long flags) \
+{ \
+ long double out; \
+ asm ("\n" \
+ " push %1""\n" \
+ " popf""\n" \
+ " fldpi""\n" \
+ " fld1""\n" \
+ " " #insn " %%st(1), %%st" "\n" \
+ " ffree %%st(1)" "\n" \
+ : "=t" (out) \
+ : "r" (flags) \
+ ); \
+ return out; \
+}
+
+TEST(fcmovb)
+TEST(fcmove)
+TEST(fcmovbe)
+TEST(fcmovu)
+TEST(fcmovnb)
+TEST(fcmovne)
+TEST(fcmovnbe)
+TEST(fcmovnu)
+
+enum {
+ CF = 1 << 0,
+ PF = 1 << 2,
+ ZF = 1 << 6,
+};
+
+void sighandler(int sig)
+{
+ printf("[FAIL]\tGot signal %d, exiting\n", sig);
+ exit(1);
+}
+
+int main(int argc, char **argv, char **envp)
+{
+ int err = 0;
+
+ /* SIGILL triggers on 32-bit kernels w/o fcomi emulation
+ * when run with "no387 nofxsr". Other signals are caught
+ * just in case.
+ */
+ signal(SIGILL, sighandler);
+ signal(SIGFPE, sighandler);
+ signal(SIGSEGV, sighandler);
+
+ printf("[RUN]\tTesting fcmovCC instructions\n");
+ /* If fcmovCC() returns 1.0, the move wasn't done */
+ err |= !(fcmovb(0) == 1.0); err |= !(fcmovnb(0) != 1.0);
+ err |= !(fcmove(0) == 1.0); err |= !(fcmovne(0) != 1.0);
+ err |= !(fcmovbe(0) == 1.0); err |= !(fcmovnbe(0) != 1.0);
+ err |= !(fcmovu(0) == 1.0); err |= !(fcmovnu(0) != 1.0);
+
+ err |= !(fcmovb(CF) != 1.0); err |= !(fcmovnb(CF) == 1.0);
+ err |= !(fcmove(CF) == 1.0); err |= !(fcmovne(CF) != 1.0);
+ err |= !(fcmovbe(CF) != 1.0); err |= !(fcmovnbe(CF) == 1.0);
+ err |= !(fcmovu(CF) == 1.0); err |= !(fcmovnu(CF) != 1.0);
+
+ err |= !(fcmovb(ZF) == 1.0); err |= !(fcmovnb(ZF) != 1.0);
+ err |= !(fcmove(ZF) != 1.0); err |= !(fcmovne(ZF) == 1.0);
+ err |= !(fcmovbe(ZF) != 1.0); err |= !(fcmovnbe(ZF) == 1.0);
+ err |= !(fcmovu(ZF) == 1.0); err |= !(fcmovnu(ZF) != 1.0);
+
+ err |= !(fcmovb(PF) == 1.0); err |= !(fcmovnb(PF) != 1.0);
+ err |= !(fcmove(PF) == 1.0); err |= !(fcmovne(PF) != 1.0);
+ err |= !(fcmovbe(PF) == 1.0); err |= !(fcmovnbe(PF) != 1.0);
+ err |= !(fcmovu(PF) != 1.0); err |= !(fcmovnu(PF) == 1.0);
+
+ if (!err)
+ printf("[OK]\tfcmovCC\n");
+ else
+ printf("[FAIL]\tfcmovCC errors: %d\n", err);
+
+ return err;
+}
diff --git a/tools/testing/selftests/x86/test_FCOMI.c b/tools/testing/selftests/x86/test_FCOMI.c
new file mode 100644
index 000000000..aec6692c6
--- /dev/null
+++ b/tools/testing/selftests/x86/test_FCOMI.c
@@ -0,0 +1,332 @@
+// SPDX-License-Identifier: GPL-2.0
+#undef _GNU_SOURCE
+#define _GNU_SOURCE 1
+#undef __USE_GNU
+#define __USE_GNU 1
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/select.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+#include <fenv.h>
+
+enum {
+ CF = 1 << 0,
+ PF = 1 << 2,
+ ZF = 1 << 6,
+ ARITH = CF | PF | ZF,
+};
+
+long res_fcomi_pi_1;
+long res_fcomi_1_pi;
+long res_fcomi_1_1;
+long res_fcomi_nan_1;
+/* sNaN is s|111 1111 1|1xx xxxx xxxx xxxx xxxx xxxx */
+/* qNaN is s|111 1111 1|0xx xxxx xxxx xxxx xxxx xxxx (some x must be nonzero) */
+int snan = 0x7fc11111;
+int qnan = 0x7f811111;
+unsigned short snan1[5];
+/* sNaN80 is s|111 1111 1111 1111 |10xx xx...xx (some x must be nonzero) */
+unsigned short snan80[5] = { 0x1111, 0x1111, 0x1111, 0x8111, 0x7fff };
+
+int test(long flags)
+{
+ feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+
+ asm ("\n"
+
+ " push %0""\n"
+ " popf""\n"
+ " fld1""\n"
+ " fldpi""\n"
+ " fcomi %%st(1), %%st" "\n"
+ " ffree %%st(0)" "\n"
+ " ffree %%st(1)" "\n"
+ " pushf""\n"
+ " pop res_fcomi_1_pi""\n"
+
+ " push %0""\n"
+ " popf""\n"
+ " fldpi""\n"
+ " fld1""\n"
+ " fcomi %%st(1), %%st" "\n"
+ " ffree %%st(0)" "\n"
+ " ffree %%st(1)" "\n"
+ " pushf""\n"
+ " pop res_fcomi_pi_1""\n"
+
+ " push %0""\n"
+ " popf""\n"
+ " fld1""\n"
+ " fld1""\n"
+ " fcomi %%st(1), %%st" "\n"
+ " ffree %%st(0)" "\n"
+ " ffree %%st(1)" "\n"
+ " pushf""\n"
+ " pop res_fcomi_1_1""\n"
+ :
+ : "r" (flags)
+ );
+ if ((res_fcomi_1_pi & ARITH) != (0)) {
+ printf("[BAD]\tfcomi_1_pi with flags:%lx\n", flags);
+ return 1;
+ }
+ if ((res_fcomi_pi_1 & ARITH) != (CF)) {
+ printf("[BAD]\tfcomi_pi_1 with flags:%lx->%lx\n", flags, res_fcomi_pi_1 & ARITH);
+ return 1;
+ }
+ if ((res_fcomi_1_1 & ARITH) != (ZF)) {
+ printf("[BAD]\tfcomi_1_1 with flags:%lx\n", flags);
+ return 1;
+ }
+ if (fetestexcept(FE_INVALID) != 0) {
+ printf("[BAD]\tFE_INVALID is set in %s\n", __func__);
+ return 1;
+ }
+ return 0;
+}
+
+int test_qnan(long flags)
+{
+ feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+
+ asm ("\n"
+ " push %0""\n"
+ " popf""\n"
+ " flds qnan""\n"
+ " fld1""\n"
+ " fnclex""\n" // fld of a qnan raised FE_INVALID, clear it
+ " fcomi %%st(1), %%st" "\n"
+ " ffree %%st(0)" "\n"
+ " ffree %%st(1)" "\n"
+ " pushf""\n"
+ " pop res_fcomi_nan_1""\n"
+ :
+ : "r" (flags)
+ );
+ if ((res_fcomi_nan_1 & ARITH) != (ZF|CF|PF)) {
+ printf("[BAD]\tfcomi_qnan_1 with flags:%lx\n", flags);
+ return 1;
+ }
+ if (fetestexcept(FE_INVALID) != FE_INVALID) {
+ printf("[BAD]\tFE_INVALID is not set in %s\n", __func__);
+ return 1;
+ }
+ return 0;
+}
+
+int testu_qnan(long flags)
+{
+ feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+
+ asm ("\n"
+ " push %0""\n"
+ " popf""\n"
+ " flds qnan""\n"
+ " fld1""\n"
+ " fnclex""\n" // fld of a qnan raised FE_INVALID, clear it
+ " fucomi %%st(1), %%st" "\n"
+ " ffree %%st(0)" "\n"
+ " ffree %%st(1)" "\n"
+ " pushf""\n"
+ " pop res_fcomi_nan_1""\n"
+ :
+ : "r" (flags)
+ );
+ if ((res_fcomi_nan_1 & ARITH) != (ZF|CF|PF)) {
+ printf("[BAD]\tfcomi_qnan_1 with flags:%lx\n", flags);
+ return 1;
+ }
+ if (fetestexcept(FE_INVALID) != 0) {
+ printf("[BAD]\tFE_INVALID is set in %s\n", __func__);
+ return 1;
+ }
+ return 0;
+}
+
+int testu_snan(long flags)
+{
+ feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+
+ asm ("\n"
+ " push %0""\n"
+ " popf""\n"
+// " flds snan""\n" // WRONG, this will convert 32-bit fp snan to a *qnan* in 80-bit fp register!
+// " fstpt snan1""\n" // if uncommented, it prints "snan1:7fff c111 1100 0000 0000" - c111, not 8111!
+// " fnclex""\n" // flds of a snan raised FE_INVALID, clear it
+ " fldt snan80""\n" // fldt never raise FE_INVALID
+ " fld1""\n"
+ " fucomi %%st(1), %%st" "\n"
+ " ffree %%st(0)" "\n"
+ " ffree %%st(1)" "\n"
+ " pushf""\n"
+ " pop res_fcomi_nan_1""\n"
+ :
+ : "r" (flags)
+ );
+ if ((res_fcomi_nan_1 & ARITH) != (ZF|CF|PF)) {
+ printf("[BAD]\tfcomi_qnan_1 with flags:%lx\n", flags);
+ return 1;
+ }
+// printf("snan:%x snan1:%04x %04x %04x %04x %04x\n", snan, snan1[4], snan1[3], snan1[2], snan1[1], snan1[0]);
+ if (fetestexcept(FE_INVALID) != FE_INVALID) {
+ printf("[BAD]\tFE_INVALID is not set in %s\n", __func__);
+ return 1;
+ }
+ return 0;
+}
+
+int testp(long flags)
+{
+ feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+
+ asm ("\n"
+
+ " push %0""\n"
+ " popf""\n"
+ " fld1""\n"
+ " fldpi""\n"
+ " fcomip %%st(1), %%st" "\n"
+ " ffree %%st(0)" "\n"
+ " pushf""\n"
+ " pop res_fcomi_1_pi""\n"
+
+ " push %0""\n"
+ " popf""\n"
+ " fldpi""\n"
+ " fld1""\n"
+ " fcomip %%st(1), %%st" "\n"
+ " ffree %%st(0)" "\n"
+ " pushf""\n"
+ " pop res_fcomi_pi_1""\n"
+
+ " push %0""\n"
+ " popf""\n"
+ " fld1""\n"
+ " fld1""\n"
+ " fcomip %%st(1), %%st" "\n"
+ " ffree %%st(0)" "\n"
+ " pushf""\n"
+ " pop res_fcomi_1_1""\n"
+ :
+ : "r" (flags)
+ );
+ if ((res_fcomi_1_pi & ARITH) != (0)) {
+ printf("[BAD]\tfcomi_1_pi with flags:%lx\n", flags);
+ return 1;
+ }
+ if ((res_fcomi_pi_1 & ARITH) != (CF)) {
+ printf("[BAD]\tfcomi_pi_1 with flags:%lx->%lx\n", flags, res_fcomi_pi_1 & ARITH);
+ return 1;
+ }
+ if ((res_fcomi_1_1 & ARITH) != (ZF)) {
+ printf("[BAD]\tfcomi_1_1 with flags:%lx\n", flags);
+ return 1;
+ }
+ if (fetestexcept(FE_INVALID) != 0) {
+ printf("[BAD]\tFE_INVALID is set in %s\n", __func__);
+ return 1;
+ }
+ return 0;
+}
+
+int testp_qnan(long flags)
+{
+ feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+
+ asm ("\n"
+ " push %0""\n"
+ " popf""\n"
+ " flds qnan""\n"
+ " fld1""\n"
+ " fnclex""\n" // fld of a qnan raised FE_INVALID, clear it
+ " fcomip %%st(1), %%st" "\n"
+ " ffree %%st(0)" "\n"
+ " pushf""\n"
+ " pop res_fcomi_nan_1""\n"
+ :
+ : "r" (flags)
+ );
+ if ((res_fcomi_nan_1 & ARITH) != (ZF|CF|PF)) {
+ printf("[BAD]\tfcomi_qnan_1 with flags:%lx\n", flags);
+ return 1;
+ }
+ if (fetestexcept(FE_INVALID) != FE_INVALID) {
+ printf("[BAD]\tFE_INVALID is not set in %s\n", __func__);
+ return 1;
+ }
+ return 0;
+}
+
+int testup_qnan(long flags)
+{
+ feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+
+ asm ("\n"
+ " push %0""\n"
+ " popf""\n"
+ " flds qnan""\n"
+ " fld1""\n"
+ " fnclex""\n" // fld of a qnan raised FE_INVALID, clear it
+ " fucomip %%st(1), %%st" "\n"
+ " ffree %%st(0)" "\n"
+ " pushf""\n"
+ " pop res_fcomi_nan_1""\n"
+ :
+ : "r" (flags)
+ );
+ if ((res_fcomi_nan_1 & ARITH) != (ZF|CF|PF)) {
+ printf("[BAD]\tfcomi_qnan_1 with flags:%lx\n", flags);
+ return 1;
+ }
+ if (fetestexcept(FE_INVALID) != 0) {
+ printf("[BAD]\tFE_INVALID is set in %s\n", __func__);
+ return 1;
+ }
+ return 0;
+}
+
+void sighandler(int sig)
+{
+ printf("[FAIL]\tGot signal %d, exiting\n", sig);
+ exit(1);
+}
+
+int main(int argc, char **argv, char **envp)
+{
+ int err = 0;
+
+ /* SIGILL triggers on 32-bit kernels w/o fcomi emulation
+ * when run with "no387 nofxsr". Other signals are caught
+ * just in case.
+ */
+ signal(SIGILL, sighandler);
+ signal(SIGFPE, sighandler);
+ signal(SIGSEGV, sighandler);
+
+ printf("[RUN]\tTesting f[u]comi[p] instructions\n");
+ err |= test(0);
+ err |= test_qnan(0);
+ err |= testu_qnan(0);
+ err |= testu_snan(0);
+ err |= test(CF|ZF|PF);
+ err |= test_qnan(CF|ZF|PF);
+ err |= testu_qnan(CF|ZF|PF);
+ err |= testu_snan(CF|ZF|PF);
+ err |= testp(0);
+ err |= testp_qnan(0);
+ err |= testup_qnan(0);
+ err |= testp(CF|ZF|PF);
+ err |= testp_qnan(CF|ZF|PF);
+ err |= testup_qnan(CF|ZF|PF);
+ if (!err)
+ printf("[OK]\tf[u]comi[p]\n");
+ else
+ printf("[FAIL]\tf[u]comi[p] errors: %d\n", err);
+
+ return err;
+}
diff --git a/tools/testing/selftests/x86/test_FISTTP.c b/tools/testing/selftests/x86/test_FISTTP.c
new file mode 100644
index 000000000..09789c0ce
--- /dev/null
+++ b/tools/testing/selftests/x86/test_FISTTP.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0
+#undef _GNU_SOURCE
+#define _GNU_SOURCE 1
+#undef __USE_GNU
+#define __USE_GNU 1
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/select.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+#include <fenv.h>
+
+unsigned long long res64 = -1;
+unsigned int res32 = -1;
+unsigned short res16 = -1;
+
+int test(void)
+{
+ int ex;
+
+ feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+ asm volatile ("\n"
+ " fld1""\n"
+ " fisttp res16""\n"
+ " fld1""\n"
+ " fisttpl res32""\n"
+ " fld1""\n"
+ " fisttpll res64""\n"
+ : : : "memory"
+ );
+ if (res16 != 1 || res32 != 1 || res64 != 1) {
+ printf("[BAD]\tfisttp 1\n");
+ return 1;
+ }
+ ex = fetestexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+ if (ex != 0) {
+ printf("[BAD]\tfisttp 1: wrong exception state\n");
+ return 1;
+ }
+
+ feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+ asm volatile ("\n"
+ " fldpi""\n"
+ " fisttp res16""\n"
+ " fldpi""\n"
+ " fisttpl res32""\n"
+ " fldpi""\n"
+ " fisttpll res64""\n"
+ : : : "memory"
+ );
+ if (res16 != 3 || res32 != 3 || res64 != 3) {
+ printf("[BAD]\tfisttp pi\n");
+ return 1;
+ }
+ ex = fetestexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+ if (ex != FE_INEXACT) {
+ printf("[BAD]\tfisttp pi: wrong exception state\n");
+ return 1;
+ }
+
+ feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+ asm volatile ("\n"
+ " fldpi""\n"
+ " fchs""\n"
+ " fisttp res16""\n"
+ " fldpi""\n"
+ " fchs""\n"
+ " fisttpl res32""\n"
+ " fldpi""\n"
+ " fchs""\n"
+ " fisttpll res64""\n"
+ : : : "memory"
+ );
+ if (res16 != 0xfffd || res32 != 0xfffffffd || res64 != 0xfffffffffffffffdULL) {
+ printf("[BAD]\tfisttp -pi\n");
+ return 1;
+ }
+ ex = fetestexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+ if (ex != FE_INEXACT) {
+ printf("[BAD]\tfisttp -pi: wrong exception state\n");
+ return 1;
+ }
+
+ feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+ asm volatile ("\n"
+ " fldln2""\n"
+ " fisttp res16""\n"
+ " fldln2""\n"
+ " fisttpl res32""\n"
+ " fldln2""\n"
+ " fisttpll res64""\n"
+ : : : "memory"
+ );
+ /* Test truncation to zero (round-to-nearest would give 1 here) */
+ if (res16 != 0 || res32 != 0 || res64 != 0) {
+ printf("[BAD]\tfisttp ln2\n");
+ return 1;
+ }
+ ex = fetestexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
+ if (ex != FE_INEXACT) {
+ printf("[BAD]\tfisttp ln2: wrong exception state\n");
+ return 1;
+ }
+
+ return 0;
+}
+
+void sighandler(int sig)
+{
+ printf("[FAIL]\tGot signal %d, exiting\n", sig);
+ exit(1);
+}
+
+int main(int argc, char **argv, char **envp)
+{
+ int err = 0;
+
+ /* SIGILL triggers on 32-bit kernels w/o fisttp emulation
+ * when run with "no387 nofxsr". Other signals are caught
+ * just in case.
+ */
+ signal(SIGILL, sighandler);
+ signal(SIGFPE, sighandler);
+ signal(SIGSEGV, sighandler);
+
+ printf("[RUN]\tTesting fisttp instructions\n");
+ err |= test();
+ if (!err)
+ printf("[OK]\tfisttp\n");
+ else
+ printf("[FAIL]\tfisttp errors: %d\n", err);
+
+ return err;
+}
diff --git a/tools/testing/selftests/x86/test_mremap_vdso.c b/tools/testing/selftests/x86/test_mremap_vdso.c
new file mode 100644
index 000000000..f0d876d48
--- /dev/null
+++ b/tools/testing/selftests/x86/test_mremap_vdso.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 32-bit test to check vDSO mremap.
+ *
+ * Copyright (c) 2016 Dmitry Safonov
+ * Suggested-by: Andrew Lutomirski
+ */
+/*
+ * Can be built statically:
+ * gcc -Os -Wall -static -m32 test_mremap_vdso.c
+ */
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+
+#include <sys/mman.h>
+#include <sys/auxv.h>
+#include <sys/syscall.h>
+#include <sys/wait.h>
+
+#define PAGE_SIZE 4096
+
+static int try_to_remap(void *vdso_addr, unsigned long size)
+{
+ void *dest_addr, *new_addr;
+
+ /* Searching for memory location where to remap */
+ dest_addr = mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+ if (dest_addr == MAP_FAILED) {
+ printf("[WARN]\tmmap failed (%d): %m\n", errno);
+ return 0;
+ }
+
+ printf("[NOTE]\tMoving vDSO: [%p, %#lx] -> [%p, %#lx]\n",
+ vdso_addr, (unsigned long)vdso_addr + size,
+ dest_addr, (unsigned long)dest_addr + size);
+ fflush(stdout);
+
+ new_addr = mremap(vdso_addr, size, size,
+ MREMAP_FIXED|MREMAP_MAYMOVE, dest_addr);
+ if ((unsigned long)new_addr == (unsigned long)-1) {
+ munmap(dest_addr, size);
+ if (errno == EINVAL) {
+ printf("[NOTE]\tvDSO partial move failed, will try with bigger size\n");
+ return -1; /* Retry with larger */
+ }
+ printf("[FAIL]\tmremap failed (%d): %m\n", errno);
+ return 1;
+ }
+
+ return 0;
+
+}
+
+int main(int argc, char **argv, char **envp)
+{
+ pid_t child;
+
+ child = fork();
+ if (child == -1) {
+ printf("[WARN]\tfailed to fork (%d): %m\n", errno);
+ return 1;
+ }
+
+ if (child == 0) {
+ unsigned long vdso_size = PAGE_SIZE;
+ unsigned long auxval;
+ int ret = -1;
+
+ auxval = getauxval(AT_SYSINFO_EHDR);
+ printf("\tAT_SYSINFO_EHDR is %#lx\n", auxval);
+ if (!auxval || auxval == -ENOENT) {
+ printf("[WARN]\tgetauxval failed\n");
+ return 0;
+ }
+
+ /* Simpler than parsing ELF header */
+ while (ret < 0) {
+ ret = try_to_remap((void *)auxval, vdso_size);
+ vdso_size += PAGE_SIZE;
+ }
+
+#ifdef __i386__
+ /* Glibc is likely to explode now - exit with raw syscall */
+ asm volatile ("int $0x80" : : "a" (__NR_exit), "b" (!!ret));
+#else /* __x86_64__ */
+ syscall(SYS_exit, ret);
+#endif
+ } else {
+ int status;
+
+ if (waitpid(child, &status, 0) != child ||
+ !WIFEXITED(status)) {
+ printf("[FAIL]\tmremap() of the vDSO does not work on this kernel!\n");
+ return 1;
+ } else if (WEXITSTATUS(status) != 0) {
+ printf("[FAIL]\tChild failed with %d\n",
+ WEXITSTATUS(status));
+ return 1;
+ }
+ printf("[OK]\n");
+ }
+
+ return 0;
+}
diff --git a/tools/testing/selftests/x86/test_syscall_vdso.c b/tools/testing/selftests/x86/test_syscall_vdso.c
new file mode 100644
index 000000000..8965c311b
--- /dev/null
+++ b/tools/testing/selftests/x86/test_syscall_vdso.c
@@ -0,0 +1,400 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 32-bit syscall ABI conformance test.
+ *
+ * Copyright (c) 2015 Denys Vlasenko
+ */
+/*
+ * Can be built statically:
+ * gcc -Os -Wall -static -m32 test_syscall_vdso.c thunks_32.S
+ */
+#undef _GNU_SOURCE
+#define _GNU_SOURCE 1
+#undef __USE_GNU
+#define __USE_GNU 1
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/select.h>
+#include <sys/time.h>
+#include <elf.h>
+#include <sys/ptrace.h>
+#include <sys/wait.h>
+
+#if !defined(__i386__)
+int main(int argc, char **argv, char **envp)
+{
+ printf("[SKIP]\tNot a 32-bit x86 userspace\n");
+ return 0;
+}
+#else
+
+long syscall_addr;
+long get_syscall(char **envp)
+{
+ Elf32_auxv_t *auxv;
+ while (*envp++ != NULL)
+ continue;
+ for (auxv = (void *)envp; auxv->a_type != AT_NULL; auxv++)
+ if (auxv->a_type == AT_SYSINFO)
+ return auxv->a_un.a_val;
+ printf("[WARN]\tAT_SYSINFO not supplied\n");
+ return 0;
+}
+
+asm (
+ " .pushsection .text\n"
+ " .global int80\n"
+ "int80:\n"
+ " int $0x80\n"
+ " ret\n"
+ " .popsection\n"
+);
+extern char int80;
+
+struct regs64 {
+ uint64_t rax, rbx, rcx, rdx;
+ uint64_t rsi, rdi, rbp, rsp;
+ uint64_t r8, r9, r10, r11;
+ uint64_t r12, r13, r14, r15;
+};
+struct regs64 regs64;
+int kernel_is_64bit;
+
+asm (
+ " .pushsection .text\n"
+ " .code64\n"
+ "get_regs64:\n"
+ " push %rax\n"
+ " mov $regs64, %eax\n"
+ " pop 0*8(%rax)\n"
+ " movq %rbx, 1*8(%rax)\n"
+ " movq %rcx, 2*8(%rax)\n"
+ " movq %rdx, 3*8(%rax)\n"
+ " movq %rsi, 4*8(%rax)\n"
+ " movq %rdi, 5*8(%rax)\n"
+ " movq %rbp, 6*8(%rax)\n"
+ " movq %rsp, 7*8(%rax)\n"
+ " movq %r8, 8*8(%rax)\n"
+ " movq %r9, 9*8(%rax)\n"
+ " movq %r10, 10*8(%rax)\n"
+ " movq %r11, 11*8(%rax)\n"
+ " movq %r12, 12*8(%rax)\n"
+ " movq %r13, 13*8(%rax)\n"
+ " movq %r14, 14*8(%rax)\n"
+ " movq %r15, 15*8(%rax)\n"
+ " ret\n"
+ "poison_regs64:\n"
+ " movq $0x7f7f7f7f, %r8\n"
+ " shl $32, %r8\n"
+ " orq $0x7f7f7f7f, %r8\n"
+ " movq %r8, %r9\n"
+ " incq %r9\n"
+ " movq %r9, %r10\n"
+ " incq %r10\n"
+ " movq %r10, %r11\n"
+ " incq %r11\n"
+ " movq %r11, %r12\n"
+ " incq %r12\n"
+ " movq %r12, %r13\n"
+ " incq %r13\n"
+ " movq %r13, %r14\n"
+ " incq %r14\n"
+ " movq %r14, %r15\n"
+ " incq %r15\n"
+ " ret\n"
+ " .code32\n"
+ " .popsection\n"
+);
+extern void get_regs64(void);
+extern void poison_regs64(void);
+extern unsigned long call64_from_32(void (*function)(void));
+void print_regs64(void)
+{
+ if (!kernel_is_64bit)
+ return;
+ printf("ax:%016llx bx:%016llx cx:%016llx dx:%016llx\n", regs64.rax, regs64.rbx, regs64.rcx, regs64.rdx);
+ printf("si:%016llx di:%016llx bp:%016llx sp:%016llx\n", regs64.rsi, regs64.rdi, regs64.rbp, regs64.rsp);
+ printf(" 8:%016llx 9:%016llx 10:%016llx 11:%016llx\n", regs64.r8 , regs64.r9 , regs64.r10, regs64.r11);
+ printf("12:%016llx 13:%016llx 14:%016llx 15:%016llx\n", regs64.r12, regs64.r13, regs64.r14, regs64.r15);
+}
+
+int check_regs64(void)
+{
+ int err = 0;
+ int num = 8;
+ uint64_t *r64 = &regs64.r8;
+ uint64_t expected = 0x7f7f7f7f7f7f7f7fULL;
+
+ if (!kernel_is_64bit)
+ return 0;
+
+ do {
+ if (*r64 == expected++)
+ continue; /* register did not change */
+ if (syscall_addr != (long)&int80) {
+ /*
+ * Non-INT80 syscall entrypoints are allowed to clobber R8+ regs:
+ * either clear them to 0, or for R11, load EFLAGS.
+ */
+ if (*r64 == 0)
+ continue;
+ if (num == 11) {
+ printf("[NOTE]\tR11 has changed:%016llx - assuming clobbered by SYSRET insn\n", *r64);
+ continue;
+ }
+ } else {
+ /*
+ * INT80 syscall entrypoint can be used by
+ * 64-bit programs too, unlike SYSCALL/SYSENTER.
+ * Therefore it must preserve R12+
+ * (they are callee-saved registers in 64-bit C ABI).
+ *
+ * Starting in Linux 4.17 (and any kernel that
+ * backports the change), R8..11 are preserved.
+ * Historically (and probably unintentionally), they
+ * were clobbered or zeroed.
+ */
+ }
+ printf("[FAIL]\tR%d has changed:%016llx\n", num, *r64);
+ err++;
+ } while (r64++, ++num < 16);
+
+ if (!err)
+ printf("[OK]\tR8..R15 did not leak kernel data\n");
+ return err;
+}
+
+int nfds;
+fd_set rfds;
+fd_set wfds;
+fd_set efds;
+struct timespec timeout;
+sigset_t sigmask;
+struct {
+ sigset_t *sp;
+ int sz;
+} sigmask_desc;
+
+void prep_args()
+{
+ nfds = 42;
+ FD_ZERO(&rfds);
+ FD_ZERO(&wfds);
+ FD_ZERO(&efds);
+ FD_SET(0, &rfds);
+ FD_SET(1, &wfds);
+ FD_SET(2, &efds);
+ timeout.tv_sec = 0;
+ timeout.tv_nsec = 123;
+ sigemptyset(&sigmask);
+ sigaddset(&sigmask, SIGINT);
+ sigaddset(&sigmask, SIGUSR2);
+ sigaddset(&sigmask, SIGRTMAX);
+ sigmask_desc.sp = &sigmask;
+ sigmask_desc.sz = 8; /* bytes */
+}
+
+static void print_flags(const char *name, unsigned long r)
+{
+ static const char *bitarray[] = {
+ "\n" ,"c\n" ,/* Carry Flag */
+ "0 " ,"1 " ,/* Bit 1 - always on */
+ "" ,"p " ,/* Parity Flag */
+ "0 " ,"3? " ,
+ "" ,"a " ,/* Auxiliary carry Flag */
+ "0 " ,"5? " ,
+ "" ,"z " ,/* Zero Flag */
+ "" ,"s " ,/* Sign Flag */
+ "" ,"t " ,/* Trap Flag */
+ "" ,"i " ,/* Interrupt Flag */
+ "" ,"d " ,/* Direction Flag */
+ "" ,"o " ,/* Overflow Flag */
+ "0 " ,"1 " ,/* I/O Privilege Level (2 bits) */
+ "0" ,"1" ,/* I/O Privilege Level (2 bits) */
+ "" ,"n " ,/* Nested Task */
+ "0 " ,"15? ",
+ "" ,"r " ,/* Resume Flag */
+ "" ,"v " ,/* Virtual Mode */
+ "" ,"ac " ,/* Alignment Check/Access Control */
+ "" ,"vif ",/* Virtual Interrupt Flag */
+ "" ,"vip ",/* Virtual Interrupt Pending */
+ "" ,"id " ,/* CPUID detection */
+ NULL
+ };
+ const char **bitstr;
+ int bit;
+
+ printf("%s=%016lx ", name, r);
+ bitstr = bitarray + 42;
+ bit = 21;
+ if ((r >> 22) != 0)
+ printf("(extra bits are set) ");
+ do {
+ if (bitstr[(r >> bit) & 1][0])
+ fputs(bitstr[(r >> bit) & 1], stdout);
+ bitstr -= 2;
+ bit--;
+ } while (bit >= 0);
+}
+
+int run_syscall(void)
+{
+ long flags, bad_arg;
+
+ prep_args();
+
+ if (kernel_is_64bit)
+ call64_from_32(poison_regs64);
+ /*print_regs64();*/
+
+ asm("\n"
+ /* Try 6-arg syscall: pselect. It should return quickly */
+ " push %%ebp\n"
+ " mov $308, %%eax\n" /* PSELECT */
+ " mov nfds, %%ebx\n" /* ebx arg1 */
+ " mov $rfds, %%ecx\n" /* ecx arg2 */
+ " mov $wfds, %%edx\n" /* edx arg3 */
+ " mov $efds, %%esi\n" /* esi arg4 */
+ " mov $timeout, %%edi\n" /* edi arg5 */
+ " mov $sigmask_desc, %%ebp\n" /* %ebp arg6 */
+ " push $0x200ed7\n" /* set almost all flags */
+ " popf\n" /* except TF, IOPL, NT, RF, VM, AC, VIF, VIP */
+ " call *syscall_addr\n"
+ /* Check that registers are not clobbered */
+ " pushf\n"
+ " pop %%eax\n"
+ " cld\n"
+ " cmp nfds, %%ebx\n" /* ebx arg1 */
+ " mov $1, %%ebx\n"
+ " jne 1f\n"
+ " cmp $rfds, %%ecx\n" /* ecx arg2 */
+ " mov $2, %%ebx\n"
+ " jne 1f\n"
+ " cmp $wfds, %%edx\n" /* edx arg3 */
+ " mov $3, %%ebx\n"
+ " jne 1f\n"
+ " cmp $efds, %%esi\n" /* esi arg4 */
+ " mov $4, %%ebx\n"
+ " jne 1f\n"
+ " cmp $timeout, %%edi\n" /* edi arg5 */
+ " mov $5, %%ebx\n"
+ " jne 1f\n"
+ " cmpl $sigmask_desc, %%ebp\n" /* %ebp arg6 */
+ " mov $6, %%ebx\n"
+ " jne 1f\n"
+ " mov $0, %%ebx\n"
+ "1:\n"
+ " pop %%ebp\n"
+ : "=a" (flags), "=b" (bad_arg)
+ :
+ : "cx", "dx", "si", "di"
+ );
+
+ if (kernel_is_64bit) {
+ memset(&regs64, 0x77, sizeof(regs64));
+ call64_from_32(get_regs64);
+ /*print_regs64();*/
+ }
+
+ /*
+ * On paravirt kernels, flags are not preserved across syscalls.
+ * Thus, we do not consider it a bug if some are changed.
+ * We just show ones which do.
+ */
+ if ((0x200ed7 ^ flags) != 0) {
+ print_flags("[WARN]\tFlags before", 0x200ed7);
+ print_flags("[WARN]\tFlags after", flags);
+ print_flags("[WARN]\tFlags change", (0x200ed7 ^ flags));
+ }
+
+ if (bad_arg) {
+ printf("[FAIL]\targ#%ld clobbered\n", bad_arg);
+ return 1;
+ }
+ printf("[OK]\tArguments are preserved across syscall\n");
+
+ return check_regs64();
+}
+
+int run_syscall_twice()
+{
+ int exitcode = 0;
+ long sv;
+
+ if (syscall_addr) {
+ printf("[RUN]\tExecuting 6-argument 32-bit syscall via VDSO\n");
+ exitcode = run_syscall();
+ }
+ sv = syscall_addr;
+ syscall_addr = (long)&int80;
+ printf("[RUN]\tExecuting 6-argument 32-bit syscall via INT 80\n");
+ exitcode += run_syscall();
+ syscall_addr = sv;
+ return exitcode;
+}
+
+void ptrace_me()
+{
+ pid_t pid;
+
+ fflush(NULL);
+ pid = fork();
+ if (pid < 0)
+ exit(1);
+ if (pid == 0) {
+ /* child */
+ if (ptrace(PTRACE_TRACEME, 0L, 0L, 0L) != 0)
+ exit(0);
+ raise(SIGSTOP);
+ return;
+ }
+ /* parent */
+ printf("[RUN]\tRunning tests under ptrace\n");
+ while (1) {
+ int status;
+ pid = waitpid(-1, &status, __WALL);
+ if (WIFEXITED(status))
+ exit(WEXITSTATUS(status));
+ if (WIFSIGNALED(status))
+ exit(WTERMSIG(status));
+ if (pid <= 0 || !WIFSTOPPED(status)) /* paranoia */
+ exit(255);
+ /*
+ * Note: we do not inject sig = WSTOPSIG(status).
+ * We probably should, but careful: do not inject SIGTRAP
+ * generated by syscall entry/exit stops.
+ * That kills the child.
+ */
+ ptrace(PTRACE_SYSCALL, pid, 0L, 0L /*sig*/);
+ }
+}
+
+int main(int argc, char **argv, char **envp)
+{
+ int exitcode = 0;
+ int cs;
+
+ asm("\n"
+ " movl %%cs, %%eax\n"
+ : "=a" (cs)
+ );
+ kernel_is_64bit = (cs == 0x23);
+ if (!kernel_is_64bit)
+ printf("[NOTE]\tNot a 64-bit kernel, won't test R8..R15 leaks\n");
+
+ /* This only works for non-static builds:
+ * syscall_addr = dlsym(dlopen("linux-gate.so.1", RTLD_NOW), "__kernel_vsyscall");
+ */
+ syscall_addr = get_syscall(envp);
+
+ exitcode += run_syscall_twice();
+ ptrace_me();
+ exitcode += run_syscall_twice();
+
+ return exitcode;
+}
+#endif
diff --git a/tools/testing/selftests/x86/test_vsyscall.c b/tools/testing/selftests/x86/test_vsyscall.c
new file mode 100644
index 000000000..5b45e6986
--- /dev/null
+++ b/tools/testing/selftests/x86/test_vsyscall.c
@@ -0,0 +1,583 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <sys/time.h>
+#include <time.h>
+#include <stdlib.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <dlfcn.h>
+#include <string.h>
+#include <inttypes.h>
+#include <signal.h>
+#include <sys/ucontext.h>
+#include <errno.h>
+#include <err.h>
+#include <sched.h>
+#include <stdbool.h>
+#include <setjmp.h>
+#include <sys/uio.h>
+
+#include "helpers.h"
+
+#ifdef __x86_64__
+# define VSYS(x) (x)
+#else
+# define VSYS(x) 0
+#endif
+
+#ifndef SYS_getcpu
+# ifdef __x86_64__
+# define SYS_getcpu 309
+# else
+# define SYS_getcpu 318
+# endif
+#endif
+
+/* max length of lines in /proc/self/maps - anything longer is skipped here */
+#define MAPS_LINE_LEN 128
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+/* vsyscalls and vDSO */
+bool vsyscall_map_r = false, vsyscall_map_x = false;
+
+typedef long (*gtod_t)(struct timeval *tv, struct timezone *tz);
+const gtod_t vgtod = (gtod_t)VSYS(0xffffffffff600000);
+gtod_t vdso_gtod;
+
+typedef int (*vgettime_t)(clockid_t, struct timespec *);
+vgettime_t vdso_gettime;
+
+typedef long (*time_func_t)(time_t *t);
+const time_func_t vtime = (time_func_t)VSYS(0xffffffffff600400);
+time_func_t vdso_time;
+
+typedef long (*getcpu_t)(unsigned *, unsigned *, void *);
+const getcpu_t vgetcpu = (getcpu_t)VSYS(0xffffffffff600800);
+getcpu_t vdso_getcpu;
+
+static void init_vdso(void)
+{
+ void *vdso = dlopen("linux-vdso.so.1", RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
+ if (!vdso)
+ vdso = dlopen("linux-gate.so.1", RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
+ if (!vdso) {
+ printf("[WARN]\tfailed to find vDSO\n");
+ return;
+ }
+
+ vdso_gtod = (gtod_t)dlsym(vdso, "__vdso_gettimeofday");
+ if (!vdso_gtod)
+ printf("[WARN]\tfailed to find gettimeofday in vDSO\n");
+
+ vdso_gettime = (vgettime_t)dlsym(vdso, "__vdso_clock_gettime");
+ if (!vdso_gettime)
+ printf("[WARN]\tfailed to find clock_gettime in vDSO\n");
+
+ vdso_time = (time_func_t)dlsym(vdso, "__vdso_time");
+ if (!vdso_time)
+ printf("[WARN]\tfailed to find time in vDSO\n");
+
+ vdso_getcpu = (getcpu_t)dlsym(vdso, "__vdso_getcpu");
+ if (!vdso_getcpu) {
+ /* getcpu() was never wired up in the 32-bit vDSO. */
+ printf("[%s]\tfailed to find getcpu in vDSO\n",
+ sizeof(long) == 8 ? "WARN" : "NOTE");
+ }
+}
+
+static int init_vsys(void)
+{
+#ifdef __x86_64__
+ int nerrs = 0;
+ FILE *maps;
+ char line[MAPS_LINE_LEN];
+ bool found = false;
+
+ maps = fopen("/proc/self/maps", "r");
+ if (!maps) {
+ printf("[WARN]\tCould not open /proc/self/maps -- assuming vsyscall is r-x\n");
+ vsyscall_map_r = true;
+ return 0;
+ }
+
+ while (fgets(line, MAPS_LINE_LEN, maps)) {
+ char r, x;
+ void *start, *end;
+ char name[MAPS_LINE_LEN];
+
+ /* sscanf() is safe here as strlen(name) >= strlen(line) */
+ if (sscanf(line, "%p-%p %c-%cp %*x %*x:%*x %*u %s",
+ &start, &end, &r, &x, name) != 5)
+ continue;
+
+ if (strcmp(name, "[vsyscall]"))
+ continue;
+
+ printf("\tvsyscall map: %s", line);
+
+ if (start != (void *)0xffffffffff600000 ||
+ end != (void *)0xffffffffff601000) {
+ printf("[FAIL]\taddress range is nonsense\n");
+ nerrs++;
+ }
+
+ printf("\tvsyscall permissions are %c-%c\n", r, x);
+ vsyscall_map_r = (r == 'r');
+ vsyscall_map_x = (x == 'x');
+
+ found = true;
+ break;
+ }
+
+ fclose(maps);
+
+ if (!found) {
+ printf("\tno vsyscall map in /proc/self/maps\n");
+ vsyscall_map_r = false;
+ vsyscall_map_x = false;
+ }
+
+ return nerrs;
+#else
+ return 0;
+#endif
+}
+
+/* syscalls */
+static inline long sys_gtod(struct timeval *tv, struct timezone *tz)
+{
+ return syscall(SYS_gettimeofday, tv, tz);
+}
+
+static inline int sys_clock_gettime(clockid_t id, struct timespec *ts)
+{
+ return syscall(SYS_clock_gettime, id, ts);
+}
+
+static inline long sys_time(time_t *t)
+{
+ return syscall(SYS_time, t);
+}
+
+static inline long sys_getcpu(unsigned * cpu, unsigned * node,
+ void* cache)
+{
+ return syscall(SYS_getcpu, cpu, node, cache);
+}
+
+static jmp_buf jmpbuf;
+static volatile unsigned long segv_err;
+
+static void sigsegv(int sig, siginfo_t *info, void *ctx_void)
+{
+ ucontext_t *ctx = (ucontext_t *)ctx_void;
+
+ segv_err = ctx->uc_mcontext.gregs[REG_ERR];
+ siglongjmp(jmpbuf, 1);
+}
+
+static double tv_diff(const struct timeval *a, const struct timeval *b)
+{
+ return (double)(a->tv_sec - b->tv_sec) +
+ (double)((int)a->tv_usec - (int)b->tv_usec) * 1e-6;
+}
+
+static int check_gtod(const struct timeval *tv_sys1,
+ const struct timeval *tv_sys2,
+ const struct timezone *tz_sys,
+ const char *which,
+ const struct timeval *tv_other,
+ const struct timezone *tz_other)
+{
+ int nerrs = 0;
+ double d1, d2;
+
+ if (tz_other && (tz_sys->tz_minuteswest != tz_other->tz_minuteswest || tz_sys->tz_dsttime != tz_other->tz_dsttime)) {
+ printf("[FAIL] %s tz mismatch\n", which);
+ nerrs++;
+ }
+
+ d1 = tv_diff(tv_other, tv_sys1);
+ d2 = tv_diff(tv_sys2, tv_other);
+ printf("\t%s time offsets: %lf %lf\n", which, d1, d2);
+
+ if (d1 < 0 || d2 < 0) {
+ printf("[FAIL]\t%s time was inconsistent with the syscall\n", which);
+ nerrs++;
+ } else {
+ printf("[OK]\t%s gettimeofday()'s timeval was okay\n", which);
+ }
+
+ return nerrs;
+}
+
+static int test_gtod(void)
+{
+ struct timeval tv_sys1, tv_sys2, tv_vdso, tv_vsys;
+ struct timezone tz_sys, tz_vdso, tz_vsys;
+ long ret_vdso = -1;
+ long ret_vsys = -1;
+ int nerrs = 0;
+
+ printf("[RUN]\ttest gettimeofday()\n");
+
+ if (sys_gtod(&tv_sys1, &tz_sys) != 0)
+ err(1, "syscall gettimeofday");
+ if (vdso_gtod)
+ ret_vdso = vdso_gtod(&tv_vdso, &tz_vdso);
+ if (vsyscall_map_x)
+ ret_vsys = vgtod(&tv_vsys, &tz_vsys);
+ if (sys_gtod(&tv_sys2, &tz_sys) != 0)
+ err(1, "syscall gettimeofday");
+
+ if (vdso_gtod) {
+ if (ret_vdso == 0) {
+ nerrs += check_gtod(&tv_sys1, &tv_sys2, &tz_sys, "vDSO", &tv_vdso, &tz_vdso);
+ } else {
+ printf("[FAIL]\tvDSO gettimeofday() failed: %ld\n", ret_vdso);
+ nerrs++;
+ }
+ }
+
+ if (vsyscall_map_x) {
+ if (ret_vsys == 0) {
+ nerrs += check_gtod(&tv_sys1, &tv_sys2, &tz_sys, "vsyscall", &tv_vsys, &tz_vsys);
+ } else {
+ printf("[FAIL]\tvsys gettimeofday() failed: %ld\n", ret_vsys);
+ nerrs++;
+ }
+ }
+
+ return nerrs;
+}
+
+static int test_time(void) {
+ int nerrs = 0;
+
+ printf("[RUN]\ttest time()\n");
+ long t_sys1, t_sys2, t_vdso = 0, t_vsys = 0;
+ long t2_sys1 = -1, t2_sys2 = -1, t2_vdso = -1, t2_vsys = -1;
+ t_sys1 = sys_time(&t2_sys1);
+ if (vdso_time)
+ t_vdso = vdso_time(&t2_vdso);
+ if (vsyscall_map_x)
+ t_vsys = vtime(&t2_vsys);
+ t_sys2 = sys_time(&t2_sys2);
+ if (t_sys1 < 0 || t_sys1 != t2_sys1 || t_sys2 < 0 || t_sys2 != t2_sys2) {
+ printf("[FAIL]\tsyscall failed (ret1:%ld output1:%ld ret2:%ld output2:%ld)\n", t_sys1, t2_sys1, t_sys2, t2_sys2);
+ nerrs++;
+ return nerrs;
+ }
+
+ if (vdso_time) {
+ if (t_vdso < 0 || t_vdso != t2_vdso) {
+ printf("[FAIL]\tvDSO failed (ret:%ld output:%ld)\n", t_vdso, t2_vdso);
+ nerrs++;
+ } else if (t_vdso < t_sys1 || t_vdso > t_sys2) {
+ printf("[FAIL]\tvDSO returned the wrong time (%ld %ld %ld)\n", t_sys1, t_vdso, t_sys2);
+ nerrs++;
+ } else {
+ printf("[OK]\tvDSO time() is okay\n");
+ }
+ }
+
+ if (vsyscall_map_x) {
+ if (t_vsys < 0 || t_vsys != t2_vsys) {
+ printf("[FAIL]\tvsyscall failed (ret:%ld output:%ld)\n", t_vsys, t2_vsys);
+ nerrs++;
+ } else if (t_vsys < t_sys1 || t_vsys > t_sys2) {
+ printf("[FAIL]\tvsyscall returned the wrong time (%ld %ld %ld)\n", t_sys1, t_vsys, t_sys2);
+ nerrs++;
+ } else {
+ printf("[OK]\tvsyscall time() is okay\n");
+ }
+ }
+
+ return nerrs;
+}
+
+static int test_getcpu(int cpu)
+{
+ int nerrs = 0;
+ long ret_sys, ret_vdso = -1, ret_vsys = -1;
+
+ printf("[RUN]\tgetcpu() on CPU %d\n", cpu);
+
+ cpu_set_t cpuset;
+ CPU_ZERO(&cpuset);
+ CPU_SET(cpu, &cpuset);
+ if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) {
+ printf("[SKIP]\tfailed to force CPU %d\n", cpu);
+ return nerrs;
+ }
+
+ unsigned cpu_sys, cpu_vdso, cpu_vsys, node_sys, node_vdso, node_vsys;
+ unsigned node = 0;
+ bool have_node = false;
+ ret_sys = sys_getcpu(&cpu_sys, &node_sys, 0);
+ if (vdso_getcpu)
+ ret_vdso = vdso_getcpu(&cpu_vdso, &node_vdso, 0);
+ if (vsyscall_map_x)
+ ret_vsys = vgetcpu(&cpu_vsys, &node_vsys, 0);
+
+ if (ret_sys == 0) {
+ if (cpu_sys != cpu) {
+ printf("[FAIL]\tsyscall reported CPU %hu but should be %d\n", cpu_sys, cpu);
+ nerrs++;
+ }
+
+ have_node = true;
+ node = node_sys;
+ }
+
+ if (vdso_getcpu) {
+ if (ret_vdso) {
+ printf("[FAIL]\tvDSO getcpu() failed\n");
+ nerrs++;
+ } else {
+ if (!have_node) {
+ have_node = true;
+ node = node_vdso;
+ }
+
+ if (cpu_vdso != cpu) {
+ printf("[FAIL]\tvDSO reported CPU %hu but should be %d\n", cpu_vdso, cpu);
+ nerrs++;
+ } else {
+ printf("[OK]\tvDSO reported correct CPU\n");
+ }
+
+ if (node_vdso != node) {
+ printf("[FAIL]\tvDSO reported node %hu but should be %hu\n", node_vdso, node);
+ nerrs++;
+ } else {
+ printf("[OK]\tvDSO reported correct node\n");
+ }
+ }
+ }
+
+ if (vsyscall_map_x) {
+ if (ret_vsys) {
+ printf("[FAIL]\tvsyscall getcpu() failed\n");
+ nerrs++;
+ } else {
+ if (!have_node) {
+ have_node = true;
+ node = node_vsys;
+ }
+
+ if (cpu_vsys != cpu) {
+ printf("[FAIL]\tvsyscall reported CPU %hu but should be %d\n", cpu_vsys, cpu);
+ nerrs++;
+ } else {
+ printf("[OK]\tvsyscall reported correct CPU\n");
+ }
+
+ if (node_vsys != node) {
+ printf("[FAIL]\tvsyscall reported node %hu but should be %hu\n", node_vsys, node);
+ nerrs++;
+ } else {
+ printf("[OK]\tvsyscall reported correct node\n");
+ }
+ }
+ }
+
+ return nerrs;
+}
+
+static int test_vsys_r(void)
+{
+#ifdef __x86_64__
+ printf("[RUN]\tChecking read access to the vsyscall page\n");
+ bool can_read;
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ *(volatile int *)0xffffffffff600000;
+ can_read = true;
+ } else {
+ can_read = false;
+ }
+
+ if (can_read && !vsyscall_map_r) {
+ printf("[FAIL]\tWe have read access, but we shouldn't\n");
+ return 1;
+ } else if (!can_read && vsyscall_map_r) {
+ printf("[FAIL]\tWe don't have read access, but we should\n");
+ return 1;
+ } else if (can_read) {
+ printf("[OK]\tWe have read access\n");
+ } else {
+ printf("[OK]\tWe do not have read access: #PF(0x%lx)\n",
+ segv_err);
+ }
+#endif
+
+ return 0;
+}
+
+static int test_vsys_x(void)
+{
+#ifdef __x86_64__
+ if (vsyscall_map_x) {
+ /* We already tested this adequately. */
+ return 0;
+ }
+
+ printf("[RUN]\tMake sure that vsyscalls really page fault\n");
+
+ bool can_exec;
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ vgtod(NULL, NULL);
+ can_exec = true;
+ } else {
+ can_exec = false;
+ }
+
+ if (can_exec) {
+ printf("[FAIL]\tExecuting the vsyscall did not page fault\n");
+ return 1;
+ } else if (segv_err & (1 << 4)) { /* INSTR */
+ printf("[OK]\tExecuting the vsyscall page failed: #PF(0x%lx)\n",
+ segv_err);
+ } else {
+ printf("[FAIL]\tExecution failed with the wrong error: #PF(0x%lx)\n",
+ segv_err);
+ return 1;
+ }
+#endif
+
+ return 0;
+}
+
+/*
+ * Debuggers expect ptrace() to be able to peek at the vsyscall page.
+ * Use process_vm_readv() as a proxy for ptrace() to test this. We
+ * want it to work in the vsyscall=emulate case and to fail in the
+ * vsyscall=xonly case.
+ *
+ * It's worth noting that this ABI is a bit nutty. write(2) can't
+ * read from the vsyscall page on any kernel version or mode. The
+ * fact that ptrace() ever worked was a nice courtesy of old kernels,
+ * but the code to support it is fairly gross.
+ */
+static int test_process_vm_readv(void)
+{
+#ifdef __x86_64__
+ char buf[4096];
+ struct iovec local, remote;
+ int ret;
+
+ printf("[RUN]\tprocess_vm_readv() from vsyscall page\n");
+
+ local.iov_base = buf;
+ local.iov_len = 4096;
+ remote.iov_base = (void *)0xffffffffff600000;
+ remote.iov_len = 4096;
+ ret = process_vm_readv(getpid(), &local, 1, &remote, 1, 0);
+ if (ret != 4096) {
+ /*
+ * We expect process_vm_readv() to work if and only if the
+ * vsyscall page is readable.
+ */
+ printf("[%s]\tprocess_vm_readv() failed (ret = %d, errno = %d)\n", vsyscall_map_r ? "FAIL" : "OK", ret, errno);
+ return vsyscall_map_r ? 1 : 0;
+ }
+
+ if (vsyscall_map_r) {
+ if (!memcmp(buf, remote.iov_base, sizeof(buf))) {
+ printf("[OK]\tIt worked and read correct data\n");
+ } else {
+ printf("[FAIL]\tIt worked but returned incorrect data\n");
+ return 1;
+ }
+ } else {
+ printf("[FAIL]\tprocess_rm_readv() succeeded, but it should have failed in this configuration\n");
+ return 1;
+ }
+#endif
+
+ return 0;
+}
+
+#ifdef __x86_64__
+static volatile sig_atomic_t num_vsyscall_traps;
+
+static void sigtrap(int sig, siginfo_t *info, void *ctx_void)
+{
+ ucontext_t *ctx = (ucontext_t *)ctx_void;
+ unsigned long ip = ctx->uc_mcontext.gregs[REG_RIP];
+
+ if (((ip ^ 0xffffffffff600000UL) & ~0xfffUL) == 0)
+ num_vsyscall_traps++;
+}
+
+static int test_emulation(void)
+{
+ time_t tmp;
+ bool is_native;
+
+ if (!vsyscall_map_x)
+ return 0;
+
+ printf("[RUN]\tchecking that vsyscalls are emulated\n");
+ sethandler(SIGTRAP, sigtrap, 0);
+ set_eflags(get_eflags() | X86_EFLAGS_TF);
+ vtime(&tmp);
+ set_eflags(get_eflags() & ~X86_EFLAGS_TF);
+
+ /*
+ * If vsyscalls are emulated, we expect a single trap in the
+ * vsyscall page -- the call instruction will trap with RIP
+ * pointing to the entry point before emulation takes over.
+ * In native mode, we expect two traps, since whatever code
+ * the vsyscall page contains will be more than just a ret
+ * instruction.
+ */
+ is_native = (num_vsyscall_traps > 1);
+
+ printf("[%s]\tvsyscalls are %s (%d instructions in vsyscall page)\n",
+ (is_native ? "FAIL" : "OK"),
+ (is_native ? "native" : "emulated"),
+ (int)num_vsyscall_traps);
+
+ return is_native;
+}
+#endif
+
+int main(int argc, char **argv)
+{
+ int nerrs = 0;
+
+ init_vdso();
+ nerrs += init_vsys();
+
+ nerrs += test_gtod();
+ nerrs += test_time();
+ nerrs += test_getcpu(0);
+ nerrs += test_getcpu(1);
+
+ sethandler(SIGSEGV, sigsegv, 0);
+ nerrs += test_vsys_r();
+ nerrs += test_vsys_x();
+
+ nerrs += test_process_vm_readv();
+
+#ifdef __x86_64__
+ nerrs += test_emulation();
+#endif
+
+ return nerrs ? 1 : 0;
+}
diff --git a/tools/testing/selftests/x86/thunks.S b/tools/testing/selftests/x86/thunks.S
new file mode 100644
index 000000000..a2d47d834
--- /dev/null
+++ b/tools/testing/selftests/x86/thunks.S
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * thunks.S - assembly helpers for mixed-bitness code
+ * Copyright (c) 2015 Andrew Lutomirski
+ *
+ * These are little helpers that make it easier to switch bitness on
+ * the fly.
+ */
+
+ .text
+
+ .global call32_from_64
+ .type call32_from_64, @function
+call32_from_64:
+ // rdi: stack to use
+ // esi: function to call
+
+ // Save registers
+ pushq %rbx
+ pushq %rbp
+ pushq %r12
+ pushq %r13
+ pushq %r14
+ pushq %r15
+ pushfq
+
+ // Switch stacks
+ mov %rsp,(%rdi)
+ mov %rdi,%rsp
+
+ // Switch to compatibility mode
+ pushq $0x23 /* USER32_CS */
+ pushq $1f
+ lretq
+
+1:
+ .code32
+ // Call the function
+ call *%esi
+ // Switch back to long mode
+ jmp $0x33,$1f
+ .code64
+
+1:
+ // Restore the stack
+ mov (%rsp),%rsp
+
+ // Restore registers
+ popfq
+ popq %r15
+ popq %r14
+ popq %r13
+ popq %r12
+ popq %rbp
+ popq %rbx
+
+ ret
+
+.size call32_from_64, .-call32_from_64
+
+.section .note.GNU-stack,"",%progbits
diff --git a/tools/testing/selftests/x86/thunks_32.S b/tools/testing/selftests/x86/thunks_32.S
new file mode 100644
index 000000000..f3f56e681
--- /dev/null
+++ b/tools/testing/selftests/x86/thunks_32.S
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * thunks_32.S - assembly helpers for mixed-bitness code
+ * Copyright (c) 2015 Denys Vlasenko
+ *
+ * These are little helpers that make it easier to switch bitness on
+ * the fly.
+ */
+
+ .text
+ .code32
+
+ .global call64_from_32
+ .type call32_from_64, @function
+
+ // 4(%esp): function to call
+call64_from_32:
+ // Fetch function address
+ mov 4(%esp), %eax
+
+ // Save registers which are callee-clobbered by 64-bit ABI
+ push %ecx
+ push %edx
+ push %esi
+ push %edi
+
+ // Switch to long mode
+ jmp $0x33,$1f
+1: .code64
+
+ // Call the function
+ call *%rax
+
+ // Switch to compatibility mode
+ push $0x23 /* USER32_CS */
+ .code32; push $1f; .code64 /* hack: can't have X86_64_32S relocation in 32-bit ELF */
+ lretq
+1: .code32
+
+ pop %edi
+ pop %esi
+ pop %edx
+ pop %ecx
+
+ ret
+
+.size call64_from_32, .-call64_from_32
+
+.section .note.GNU-stack,"",%progbits
diff --git a/tools/testing/selftests/x86/trivial_32bit_program.c b/tools/testing/selftests/x86/trivial_32bit_program.c
new file mode 100644
index 000000000..aa1f58c2f
--- /dev/null
+++ b/tools/testing/selftests/x86/trivial_32bit_program.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Trivial program to check that we have a valid 32-bit build environment.
+ * Copyright (c) 2015 Andy Lutomirski
+ */
+
+#ifndef __i386__
+# error wrong architecture
+#endif
+
+#include <stdio.h>
+
+int main()
+{
+ printf("\n");
+
+ return 0;
+}
diff --git a/tools/testing/selftests/x86/trivial_64bit_program.c b/tools/testing/selftests/x86/trivial_64bit_program.c
new file mode 100644
index 000000000..39f4b84fb
--- /dev/null
+++ b/tools/testing/selftests/x86/trivial_64bit_program.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Trivial program to check that we have a valid 64-bit build environment.
+ * Copyright (c) 2015 Andy Lutomirski
+ */
+
+#ifndef __x86_64__
+# error wrong architecture
+#endif
+
+#include <stdio.h>
+
+int main()
+{
+ printf("\n");
+
+ return 0;
+}
diff --git a/tools/testing/selftests/x86/trivial_program.c b/tools/testing/selftests/x86/trivial_program.c
new file mode 100644
index 000000000..46a447163
--- /dev/null
+++ b/tools/testing/selftests/x86/trivial_program.c
@@ -0,0 +1,10 @@
+/* Trivial program to check that compilation with certain flags is working. */
+
+#include <stdio.h>
+
+int
+main(void)
+{
+ puts("");
+ return 0;
+}
diff --git a/tools/testing/selftests/x86/unwind_vdso.c b/tools/testing/selftests/x86/unwind_vdso.c
new file mode 100644
index 000000000..4c311e1af
--- /dev/null
+++ b/tools/testing/selftests/x86/unwind_vdso.c
@@ -0,0 +1,183 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * unwind_vdso.c - tests unwind info for AT_SYSINFO in the vDSO
+ * Copyright (c) 2014-2015 Andrew Lutomirski
+ *
+ * This tests __kernel_vsyscall's unwind info.
+ */
+
+#define _GNU_SOURCE
+
+#include <features.h>
+#include <stdio.h>
+
+#include "helpers.h"
+
+#if defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ < 16
+
+int main()
+{
+ /* We need getauxval(). */
+ printf("[SKIP]\tGLIBC before 2.16 cannot compile this test\n");
+ return 0;
+}
+
+#else
+
+#include <sys/time.h>
+#include <stdlib.h>
+#include <syscall.h>
+#include <unistd.h>
+#include <string.h>
+#include <inttypes.h>
+#include <sys/mman.h>
+#include <signal.h>
+#include <sys/ucontext.h>
+#include <err.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include <sys/ptrace.h>
+#include <sys/user.h>
+#include <link.h>
+#include <sys/auxv.h>
+#include <dlfcn.h>
+#include <unwind.h>
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+ int flags)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = handler;
+ sa.sa_flags = SA_SIGINFO | flags;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
+static volatile sig_atomic_t nerrs;
+static unsigned long sysinfo;
+static bool got_sysinfo = false;
+static unsigned long return_address;
+
+struct unwind_state {
+ unsigned long ip; /* trap source */
+ int depth; /* -1 until we hit the trap source */
+};
+
+_Unwind_Reason_Code trace_fn(struct _Unwind_Context * ctx, void *opaque)
+{
+ struct unwind_state *state = opaque;
+ unsigned long ip = _Unwind_GetIP(ctx);
+
+ if (state->depth == -1) {
+ if (ip == state->ip)
+ state->depth = 0;
+ else
+ return _URC_NO_REASON; /* Not there yet */
+ }
+ printf("\t 0x%lx\n", ip);
+
+ if (ip == return_address) {
+ /* Here we are. */
+ unsigned long eax = _Unwind_GetGR(ctx, 0);
+ unsigned long ecx = _Unwind_GetGR(ctx, 1);
+ unsigned long edx = _Unwind_GetGR(ctx, 2);
+ unsigned long ebx = _Unwind_GetGR(ctx, 3);
+ unsigned long ebp = _Unwind_GetGR(ctx, 5);
+ unsigned long esi = _Unwind_GetGR(ctx, 6);
+ unsigned long edi = _Unwind_GetGR(ctx, 7);
+ bool ok = (eax == SYS_getpid || eax == getpid()) &&
+ ebx == 1 && ecx == 2 && edx == 3 &&
+ esi == 4 && edi == 5 && ebp == 6;
+
+ if (!ok)
+ nerrs++;
+ printf("[%s]\t NR = %ld, args = %ld, %ld, %ld, %ld, %ld, %ld\n",
+ (ok ? "OK" : "FAIL"),
+ eax, ebx, ecx, edx, esi, edi, ebp);
+
+ return _URC_NORMAL_STOP;
+ } else {
+ state->depth++;
+ return _URC_NO_REASON;
+ }
+}
+
+static void sigtrap(int sig, siginfo_t *info, void *ctx_void)
+{
+ ucontext_t *ctx = (ucontext_t *)ctx_void;
+ struct unwind_state state;
+ unsigned long ip = ctx->uc_mcontext.gregs[REG_EIP];
+
+ if (!got_sysinfo && ip == sysinfo) {
+ got_sysinfo = true;
+
+ /* Find the return address. */
+ return_address = *(unsigned long *)(unsigned long)ctx->uc_mcontext.gregs[REG_ESP];
+
+ printf("\tIn vsyscall at 0x%lx, returning to 0x%lx\n",
+ ip, return_address);
+ }
+
+ if (!got_sysinfo)
+ return; /* Not there yet */
+
+ if (ip == return_address) {
+ ctx->uc_mcontext.gregs[REG_EFL] &= ~X86_EFLAGS_TF;
+ printf("\tVsyscall is done\n");
+ return;
+ }
+
+ printf("\tSIGTRAP at 0x%lx\n", ip);
+
+ state.ip = ip;
+ state.depth = -1;
+ _Unwind_Backtrace(trace_fn, &state);
+}
+
+int main()
+{
+ sysinfo = getauxval(AT_SYSINFO);
+ printf("\tAT_SYSINFO is 0x%lx\n", sysinfo);
+
+ Dl_info info;
+ if (!dladdr((void *)sysinfo, &info)) {
+ printf("[WARN]\tdladdr failed on AT_SYSINFO\n");
+ } else {
+ printf("[OK]\tAT_SYSINFO maps to %s, loaded at 0x%p\n",
+ info.dli_fname, info.dli_fbase);
+ }
+
+ sethandler(SIGTRAP, sigtrap, 0);
+
+ syscall(SYS_getpid); /* Force symbol binding without TF set. */
+ printf("[RUN]\tSet TF and check a fast syscall\n");
+ set_eflags(get_eflags() | X86_EFLAGS_TF);
+ syscall(SYS_getpid, 1, 2, 3, 4, 5, 6);
+ if (!got_sysinfo) {
+ set_eflags(get_eflags() & ~X86_EFLAGS_TF);
+
+ /*
+ * The most likely cause of this is that you're on Debian or
+ * a Debian-based distro, you're missing libc6-i686, and you're
+ * affected by libc/19006 (https://sourceware.org/PR19006).
+ */
+ printf("[WARN]\tsyscall(2) didn't enter AT_SYSINFO\n");
+ }
+
+ if (get_eflags() & X86_EFLAGS_TF) {
+ printf("[FAIL]\tTF is still set\n");
+ nerrs++;
+ }
+
+ if (nerrs) {
+ printf("[FAIL]\tThere were errors\n");
+ return 1;
+ } else {
+ printf("[OK]\tAll is well\n");
+ return 0;
+ }
+}
+
+#endif /* New enough libc */
diff --git a/tools/testing/selftests/x86/vdso_restorer.c b/tools/testing/selftests/x86/vdso_restorer.c
new file mode 100644
index 000000000..fe99f2434
--- /dev/null
+++ b/tools/testing/selftests/x86/vdso_restorer.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * vdso_restorer.c - tests vDSO-based signal restore
+ * Copyright (c) 2015 Andrew Lutomirski
+ *
+ * This makes sure that sa_restorer == NULL keeps working on 32-bit
+ * configurations. Modern glibc doesn't use it under any circumstances,
+ * so it's easy to overlook breakage.
+ *
+ * 64-bit userspace has never supported sa_restorer == NULL, so this is
+ * 32-bit only.
+ */
+
+#define _GNU_SOURCE
+
+#include <err.h>
+#include <stdio.h>
+#include <dlfcn.h>
+#include <string.h>
+#include <signal.h>
+#include <unistd.h>
+#include <syscall.h>
+#include <sys/syscall.h>
+
+/* Open-code this -- the headers are too messy to easily use them. */
+struct real_sigaction {
+ void *handler;
+ unsigned long flags;
+ void *restorer;
+ unsigned int mask[2];
+};
+
+static volatile sig_atomic_t handler_called;
+
+static void handler_with_siginfo(int sig, siginfo_t *info, void *ctx_void)
+{
+ handler_called = 1;
+}
+
+static void handler_without_siginfo(int sig)
+{
+ handler_called = 1;
+}
+
+int main()
+{
+ int nerrs = 0;
+ struct real_sigaction sa;
+
+ void *vdso = dlopen("linux-vdso.so.1",
+ RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
+ if (!vdso)
+ vdso = dlopen("linux-gate.so.1",
+ RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
+ if (!vdso) {
+ printf("[SKIP]\tFailed to find vDSO. Tests are not expected to work.\n");
+ return 0;
+ }
+
+ memset(&sa, 0, sizeof(sa));
+ sa.handler = handler_with_siginfo;
+ sa.flags = SA_SIGINFO;
+ sa.restorer = NULL; /* request kernel-provided restorer */
+
+ printf("[RUN]\tRaise a signal, SA_SIGINFO, sa.restorer == NULL\n");
+
+ if (syscall(SYS_rt_sigaction, SIGUSR1, &sa, NULL, 8) != 0)
+ err(1, "raw rt_sigaction syscall");
+
+ raise(SIGUSR1);
+
+ if (handler_called) {
+ printf("[OK]\tSA_SIGINFO handler returned successfully\n");
+ } else {
+ printf("[FAIL]\tSA_SIGINFO handler was not called\n");
+ nerrs++;
+ }
+
+ printf("[RUN]\tRaise a signal, !SA_SIGINFO, sa.restorer == NULL\n");
+
+ sa.flags = 0;
+ sa.handler = handler_without_siginfo;
+ if (syscall(SYS_sigaction, SIGUSR1, &sa, 0) != 0)
+ err(1, "raw sigaction syscall");
+ handler_called = 0;
+
+ raise(SIGUSR1);
+
+ if (handler_called) {
+ printf("[OK]\t!SA_SIGINFO handler returned successfully\n");
+ } else {
+ printf("[FAIL]\t!SA_SIGINFO handler was not called\n");
+ nerrs++;
+ }
+}