Adding upstream version 6.6.15.upstream/6.6.15

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

1 files changed, 1109 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
new file mode 100644
index 0000000000..7112adc597
--- /dev/null
+++ b/arch/powerpc/kernel/module_64.c
@@ -0,0 +1,1109 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*  Kernel module help for PPC64.
+    Copyright (C) 2001, 2003 Rusty Russell IBM Corporation.
+
+*/
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/elf.h>
+#include <linux/moduleloader.h>
+#include <linux/err.h>
+#include <linux/vmalloc.h>
+#include <linux/ftrace.h>
+#include <linux/bug.h>
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <asm/module.h>
+#include <asm/firmware.h>
+#include <asm/code-patching.h>
+#include <linux/sort.h>
+#include <asm/setup.h>
+#include <asm/sections.h>
+#include <asm/inst.h>
+
+/* FIXME: We don't do .init separately.  To do this, we'd need to have
+   a separate r2 value in the init and core section, and stub between
+   them, too.
+
+   Using a magic allocator which places modules within 32MB solves
+   this, and makes other things simpler.  Anton?
+   --RR.  */
+
+bool module_elf_check_arch(Elf_Ehdr *hdr)
+{
+	unsigned long abi_level = hdr->e_flags & 0x3;
+
+	if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2))
+		return abi_level == 2;
+	else
+		return abi_level < 2;
+}
+
+#ifdef CONFIG_PPC64_ELF_ABI_V2
+
+static func_desc_t func_desc(unsigned long addr)
+{
+	func_desc_t desc = {
+		.addr = addr,
+	};
+
+	return desc;
+}
+
+/* PowerPC64 specific values for the Elf64_Sym st_other field.  */
+#define STO_PPC64_LOCAL_BIT	5
+#define STO_PPC64_LOCAL_MASK	(7 << STO_PPC64_LOCAL_BIT)
+#define PPC64_LOCAL_ENTRY_OFFSET(other)					\
+ (((1 << (((other) & STO_PPC64_LOCAL_MASK) >> STO_PPC64_LOCAL_BIT)) >> 2) << 2)
+
+static unsigned int local_entry_offset(const Elf64_Sym *sym)
+{
+	/* sym->st_other indicates offset to local entry point
+	 * (otherwise it will assume r12 is the address of the start
+	 * of function and try to derive r2 from it). */
+	return PPC64_LOCAL_ENTRY_OFFSET(sym->st_other);
+}
+#else
+
+static func_desc_t func_desc(unsigned long addr)
+{
+	return *(struct func_desc *)addr;
+}
+static unsigned int local_entry_offset(const Elf64_Sym *sym)
+{
+	return 0;
+}
+
+void *dereference_module_function_descriptor(struct module *mod, void *ptr)
+{
+	if (ptr < (void *)mod->arch.start_opd ||
+			ptr >= (void *)mod->arch.end_opd)
+		return ptr;
+
+	return dereference_function_descriptor(ptr);
+}
+#endif
+
+static unsigned long func_addr(unsigned long addr)
+{
+	return func_desc(addr).addr;
+}
+
+static unsigned long stub_func_addr(func_desc_t func)
+{
+	return func.addr;
+}
+
+#define STUB_MAGIC 0x73747562 /* stub */
+
+/* Like PPC32, we need little trampolines to do > 24-bit jumps (into
+   the kernel itself).  But on PPC64, these need to be used for every
+   jump, actually, to reset r2 (TOC+0x8000). */
+struct ppc64_stub_entry {
+	/*
+	 * 28 byte jump instruction sequence (7 instructions) that can
+	 * hold ppc64_stub_insns or stub_insns. Must be 8-byte aligned
+	 * with PCREL kernels that use prefix instructions in the stub.
+	 */
+	u32 jump[7];
+	/* Used by ftrace to identify stubs */
+	u32 magic;
+	/* Data for the above code */
+	func_desc_t funcdata;
+} __aligned(8);
+
+struct ppc64_got_entry {
+	u64 addr;
+};
+
+/*
+ * PPC64 uses 24 bit jumps, but we need to jump into other modules or
+ * the kernel which may be further.  So we jump to a stub.
+ *
+ * Target address and TOC are loaded from function descriptor in the
+ * ppc64_stub_entry.
+ *
+ * r12 is used to generate the target address, which is required for the
+ * ELFv2 global entry point calling convention.
+ *
+ * TOC handling:
+ * - PCREL does not have a TOC.
+ * - ELFv2 non-PCREL just has to save r2, the callee is responsible for
+ *   setting its own TOC pointer at the global entry address.
+ * - ELFv1 must load the new TOC pointer from the function descriptor.
+ */
+static u32 ppc64_stub_insns[] = {
+#ifdef CONFIG_PPC_KERNEL_PCREL
+	/* pld r12,addr */
+	PPC_PREFIX_8LS | __PPC_PRFX_R(1),
+	PPC_INST_PLD | ___PPC_RT(_R12),
+#else
+	PPC_RAW_ADDIS(_R11, _R2, 0),
+	PPC_RAW_ADDI(_R11, _R11, 0),
+	/* Save current r2 value in magic place on the stack. */
+	PPC_RAW_STD(_R2, _R1, R2_STACK_OFFSET),
+	PPC_RAW_LD(_R12, _R11, 32),
+#ifdef CONFIG_PPC64_ELF_ABI_V1
+	/* Set up new r2 from function descriptor */
+	PPC_RAW_LD(_R2, _R11, 40),
+#endif
+#endif
+	PPC_RAW_MTCTR(_R12),
+	PPC_RAW_BCTR(),
+};
+
+/*
+ * Count how many different r_type relocations (different symbol,
+ * different addend).
+ */
+static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num,
+				 unsigned long r_type)
+{
+	unsigned int i, r_info, r_addend, _count_relocs;
+
+	/* FIXME: Only count external ones --RR */
+	_count_relocs = 0;
+	r_info = 0;
+	r_addend = 0;
+	for (i = 0; i < num; i++)
+		/* Only count r_type relocs, others don't need stubs */
+		if (ELF64_R_TYPE(rela[i].r_info) == r_type &&
+		    (r_info != ELF64_R_SYM(rela[i].r_info) ||
+		     r_addend != rela[i].r_addend)) {
+			_count_relocs++;
+			r_info = ELF64_R_SYM(rela[i].r_info);
+			r_addend = rela[i].r_addend;
+		}
+
+	return _count_relocs;
+}
+
+static int relacmp(const void *_x, const void *_y)
+{
+	const Elf64_Rela *x, *y;
+
+	y = (Elf64_Rela *)_x;
+	x = (Elf64_Rela *)_y;
+
+	/* Compare the entire r_info (as opposed to ELF64_R_SYM(r_info) only) to
+	 * make the comparison cheaper/faster. It won't affect the sorting or
+	 * the counting algorithms' performance
+	 */
+	if (x->r_info < y->r_info)
+		return -1;
+	else if (x->r_info > y->r_info)
+		return 1;
+	else if (x->r_addend < y->r_addend)
+		return -1;
+	else if (x->r_addend > y->r_addend)
+		return 1;
+	else
+		return 0;
+}
+
+/* Get size of potential trampolines required. */
+static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
+				    const Elf64_Shdr *sechdrs)
+{
+	/* One extra reloc so it's always 0-addr terminated */
+	unsigned long relocs = 1;
+	unsigned i;
+
+	/* Every relocated section... */
+	for (i = 1; i < hdr->e_shnum; i++) {
+		if (sechdrs[i].sh_type == SHT_RELA) {
+			pr_debug("Found relocations in section %u\n", i);
+			pr_debug("Ptr: %p.  Number: %Lu\n",
+			       (void *)sechdrs[i].sh_addr,
+			       sechdrs[i].sh_size / sizeof(Elf64_Rela));
+
+			/* Sort the relocation information based on a symbol and
+			 * addend key. This is a stable O(n*log n) complexity
+			 * algorithm but it will reduce the complexity of
+			 * count_relocs() to linear complexity O(n)
+			 */
+			sort((void *)sechdrs[i].sh_addr,
+			     sechdrs[i].sh_size / sizeof(Elf64_Rela),
+			     sizeof(Elf64_Rela), relacmp, NULL);
+
+			relocs += count_relocs((void *)sechdrs[i].sh_addr,
+					       sechdrs[i].sh_size
+					       / sizeof(Elf64_Rela),
+					       R_PPC_REL24);
+#ifdef CONFIG_PPC_KERNEL_PCREL
+			relocs += count_relocs((void *)sechdrs[i].sh_addr,
+					       sechdrs[i].sh_size
+					       / sizeof(Elf64_Rela),
+					       R_PPC64_REL24_NOTOC);
+#endif
+		}
+	}
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+	/* make the trampoline to the ftrace_caller */
+	relocs++;
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+	/* an additional one for ftrace_regs_caller */
+	relocs++;
+#endif
+#endif
+
+	pr_debug("Looks like a total of %lu stubs, max\n", relocs);
+	return relocs * sizeof(struct ppc64_stub_entry);
+}
+
+#ifdef CONFIG_PPC_KERNEL_PCREL
+static int count_pcpu_relocs(const Elf64_Shdr *sechdrs,
+			     const Elf64_Rela *rela, unsigned int num,
+			     unsigned int symindex, unsigned int pcpu)
+{
+	unsigned int i, r_info, r_addend, _count_relocs;
+
+	_count_relocs = 0;
+	r_info = 0;
+	r_addend = 0;
+
+	for (i = 0; i < num; i++) {
+		Elf64_Sym *sym;
+
+		/* This is the symbol it is referring to */
+		sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
+			+ ELF64_R_SYM(rela[i].r_info);
+
+		if (sym->st_shndx == pcpu &&
+		    (r_info != ELF64_R_SYM(rela[i].r_info) ||
+		     r_addend != rela[i].r_addend)) {
+			_count_relocs++;
+			r_info = ELF64_R_SYM(rela[i].r_info);
+			r_addend = rela[i].r_addend;
+		}
+	}
+
+	return _count_relocs;
+}
+
+/* Get size of potential GOT required. */
+static unsigned long get_got_size(const Elf64_Ehdr *hdr,
+				  const Elf64_Shdr *sechdrs,
+				  struct module *me)
+{
+	/* One extra reloc so it's always 0-addr terminated */
+	unsigned long relocs = 1;
+	unsigned int i, symindex = 0;
+
+	for (i = 1; i < hdr->e_shnum; i++) {
+		if (sechdrs[i].sh_type == SHT_SYMTAB) {
+			symindex = i;
+			break;
+		}
+	}
+	WARN_ON_ONCE(!symindex);
+
+	/* Every relocated section... */
+	for (i = 1; i < hdr->e_shnum; i++) {
+		if (sechdrs[i].sh_type == SHT_RELA) {
+			pr_debug("Found relocations in section %u\n", i);
+			pr_debug("Ptr: %p.  Number: %llu\n", (void *)sechdrs[i].sh_addr,
+				 sechdrs[i].sh_size / sizeof(Elf64_Rela));
+
+			/*
+			 * Sort the relocation information based on a symbol and
+			 * addend key. This is a stable O(n*log n) complexity
+			 * algorithm but it will reduce the complexity of
+			 * count_relocs() to linear complexity O(n)
+			 */
+			sort((void *)sechdrs[i].sh_addr,
+			     sechdrs[i].sh_size / sizeof(Elf64_Rela),
+			     sizeof(Elf64_Rela), relacmp, NULL);
+
+			relocs += count_relocs((void *)sechdrs[i].sh_addr,
+					       sechdrs[i].sh_size
+					       / sizeof(Elf64_Rela),
+					       R_PPC64_GOT_PCREL34);
+
+			/*
+			 * Percpu data access typically gets linked with
+			 * REL34 relocations, but the percpu section gets
+			 * moved at load time and requires that to be
+			 * converted to GOT linkage.
+			 */
+			if (IS_ENABLED(CONFIG_SMP) && symindex)
+				relocs += count_pcpu_relocs(sechdrs,
+						(void *)sechdrs[i].sh_addr,
+					       sechdrs[i].sh_size
+					       / sizeof(Elf64_Rela),
+					       symindex, me->arch.pcpu_section);
+		}
+	}
+
+	pr_debug("Looks like a total of %lu GOT entries, max\n", relocs);
+	return relocs * sizeof(struct ppc64_got_entry);
+}
+#else /* CONFIG_PPC_KERNEL_PCREL */
+
+/* Still needed for ELFv2, for .TOC. */
+static void dedotify_versions(struct modversion_info *vers,
+			      unsigned long size)
+{
+	struct modversion_info *end;
+
+	for (end = (void *)vers + size; vers < end; vers++)
+		if (vers->name[0] == '.') {
+			memmove(vers->name, vers->name+1, strlen(vers->name));
+		}
+}
+
+/*
+ * Undefined symbols which refer to .funcname, hack to funcname. Make .TOC.
+ * seem to be defined (value set later).
+ */
+static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab)
+{
+	unsigned int i;
+
+	for (i = 1; i < numsyms; i++) {
+		if (syms[i].st_shndx == SHN_UNDEF) {
+			char *name = strtab + syms[i].st_name;
+			if (name[0] == '.') {
+				if (strcmp(name+1, "TOC.") == 0)
+					syms[i].st_shndx = SHN_ABS;
+				syms[i].st_name++;
+			}
+		}
+	}
+}
+
+static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs,
+			       const char *strtab,
+			       unsigned int symindex)
+{
+	unsigned int i, numsyms;
+	Elf64_Sym *syms;
+
+	syms = (Elf64_Sym *)sechdrs[symindex].sh_addr;
+	numsyms = sechdrs[symindex].sh_size / sizeof(Elf64_Sym);
+
+	for (i = 1; i < numsyms; i++) {
+		if (syms[i].st_shndx == SHN_ABS
+		    && strcmp(strtab + syms[i].st_name, "TOC.") == 0)
+			return &syms[i];
+	}
+	return NULL;
+}
+#endif /* CONFIG_PPC_KERNEL_PCREL */
+
+bool module_init_section(const char *name)
+{
+	/* We don't handle .init for the moment: always return false. */
+	return false;
+}
+
+int module_frob_arch_sections(Elf64_Ehdr *hdr,
+			      Elf64_Shdr *sechdrs,
+			      char *secstrings,
+			      struct module *me)
+{
+	unsigned int i;
+
+	/* Find .toc and .stubs sections, symtab and strtab */
+	for (i = 1; i < hdr->e_shnum; i++) {
+		if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0)
+			me->arch.stubs_section = i;
+#ifdef CONFIG_PPC_KERNEL_PCREL
+		else if (strcmp(secstrings + sechdrs[i].sh_name, ".data..percpu") == 0)
+			me->arch.pcpu_section = i;
+		else if (strcmp(secstrings + sechdrs[i].sh_name, ".mygot") == 0) {
+			me->arch.got_section = i;
+			if (sechdrs[i].sh_addralign < 8)
+				sechdrs[i].sh_addralign = 8;
+		}
+#else
+		else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0) {
+			me->arch.toc_section = i;
+			if (sechdrs[i].sh_addralign < 8)
+				sechdrs[i].sh_addralign = 8;
+		}
+		else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0)
+			dedotify_versions((void *)hdr + sechdrs[i].sh_offset,
+					  sechdrs[i].sh_size);
+
+		if (sechdrs[i].sh_type == SHT_SYMTAB)
+			dedotify((void *)hdr + sechdrs[i].sh_offset,
+				 sechdrs[i].sh_size / sizeof(Elf64_Sym),
+				 (void *)hdr
+				 + sechdrs[sechdrs[i].sh_link].sh_offset);
+#endif
+	}
+
+	if (!me->arch.stubs_section) {
+		pr_err("%s: doesn't contain .stubs.\n", me->name);
+		return -ENOEXEC;
+	}
+
+#ifdef CONFIG_PPC_KERNEL_PCREL
+	if (!me->arch.got_section) {
+		pr_err("%s: doesn't contain .mygot.\n", me->name);
+		return -ENOEXEC;
+	}
+
+	/* Override the got size */
+	sechdrs[me->arch.got_section].sh_size = get_got_size(hdr, sechdrs, me);
+#else
+	/* If we don't have a .toc, just use .stubs.  We need to set r2
+	   to some reasonable value in case the module calls out to
+	   other functions via a stub, or if a function pointer escapes
+	   the module by some means.  */
+	if (!me->arch.toc_section)
+		me->arch.toc_section = me->arch.stubs_section;
+#endif
+
+	/* Override the stubs size */
+	sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs);
+
+	return 0;
+}
+
+#if defined(CONFIG_MPROFILE_KERNEL) || defined(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)
+
+static u32 stub_insns[] = {
+#ifdef CONFIG_PPC_KERNEL_PCREL
+	PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernelbase)),
+	PPC_RAW_NOP(), /* align the prefix insn */
+	/* paddi r12,r12,addr */
+	PPC_PREFIX_MLS | __PPC_PRFX_R(0),
+	PPC_INST_PADDI | ___PPC_RT(_R12) | ___PPC_RA(_R12),
+	PPC_RAW_MTCTR(_R12),
+	PPC_RAW_BCTR(),
+#else
+	PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernel_toc)),
+	PPC_RAW_ADDIS(_R12, _R12, 0),
+	PPC_RAW_ADDI(_R12, _R12, 0),
+	PPC_RAW_MTCTR(_R12),
+	PPC_RAW_BCTR(),
+#endif
+};
+
+/*
+ * For mprofile-kernel we use a special stub for ftrace_caller() because we
+ * can't rely on r2 containing this module's TOC when we enter the stub.
+ *
+ * That can happen if the function calling us didn't need to use the toc. In
+ * that case it won't have setup r2, and the r2 value will be either the
+ * kernel's toc, or possibly another modules toc.
+ *
+ * To deal with that this stub uses the kernel toc, which is always accessible
+ * via the paca (in r13). The target (ftrace_caller()) is responsible for
+ * saving and restoring the toc before returning.
+ */
+static inline int create_ftrace_stub(struct ppc64_stub_entry *entry,
+					unsigned long addr,
+					struct module *me)
+{
+	long reladdr;
+
+	if ((unsigned long)entry->jump % 8 != 0) {
+		pr_err("%s: Address of stub entry is not 8-byte aligned\n", me->name);
+		return 0;
+	}
+
+	BUILD_BUG_ON(sizeof(stub_insns) > sizeof(entry->jump));
+	memcpy(entry->jump, stub_insns, sizeof(stub_insns));
+
+	if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) {
+		/* Stub uses address relative to kernel base (from the paca) */
+		reladdr = addr - local_paca->kernelbase;
+		if (reladdr > 0x1FFFFFFFFL || reladdr < -0x200000000L) {
+			pr_err("%s: Address of %ps out of range of 34-bit relative address.\n",
+				me->name, (void *)addr);
+			return 0;
+		}
+
+		entry->jump[2] |= IMM_H18(reladdr);
+		entry->jump[3] |= IMM_L(reladdr);
+	} else {
+		/* Stub uses address relative to kernel toc (from the paca) */
+		reladdr = addr - kernel_toc_addr();
+		if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
+			pr_err("%s: Address of %ps out of range of kernel_toc.\n",
+				me->name, (void *)addr);
+			return 0;
+		}
+
+		entry->jump[1] |= PPC_HA(reladdr);
+		entry->jump[2] |= PPC_LO(reladdr);
+	}
+
+	/* Even though we don't use funcdata in the stub, it's needed elsewhere. */
+	entry->funcdata = func_desc(addr);
+	entry->magic = STUB_MAGIC;
+
+	return 1;
+}
+
+static bool is_mprofile_ftrace_call(const char *name)
+{
+	if (!strcmp("_mcount", name))
+		return true;
+#ifdef CONFIG_DYNAMIC_FTRACE
+	if (!strcmp("ftrace_caller", name))
+		return true;
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+	if (!strcmp("ftrace_regs_caller", name))
+		return true;
+#endif
+#endif
+
+	return false;
+}
+#else
+static inline int create_ftrace_stub(struct ppc64_stub_entry *entry,
+					unsigned long addr,
+					struct module *me)
+{
+	return 0;
+}
+
+static bool is_mprofile_ftrace_call(const char *name)
+{
+	return false;
+}
+#endif
+
+/*
+ * r2 is the TOC pointer: it actually points 0x8000 into the TOC (this gives the
+ * value maximum span in an instruction which uses a signed offset). Round down
+ * to a 256 byte boundary for the odd case where we are setting up r2 without a
+ * .toc section.
+ */
+static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me)
+{
+#ifndef CONFIG_PPC_KERNEL_PCREL
+	return (sechdrs[me->arch.toc_section].sh_addr & ~0xfful) + 0x8000;
+#else
+	return -1;
+#endif
+}
+
+/* Patch stub to reference function and correct r2 value. */
+static inline int create_stub(const Elf64_Shdr *sechdrs,
+			      struct ppc64_stub_entry *entry,
+			      unsigned long addr,
+			      struct module *me,
+			      const char *name)
+{
+	long reladdr;
+	func_desc_t desc;
+	int i;
+
+	if (is_mprofile_ftrace_call(name))
+		return create_ftrace_stub(entry, addr, me);
+
+	if ((unsigned long)entry->jump % 8 != 0) {
+		pr_err("%s: Address of stub entry is not 8-byte aligned\n", me->name);
+		return 0;
+	}
+
+	BUILD_BUG_ON(sizeof(ppc64_stub_insns) > sizeof(entry->jump));
+	for (i = 0; i < ARRAY_SIZE(ppc64_stub_insns); i++) {
+		if (patch_instruction(&entry->jump[i],
+				      ppc_inst(ppc64_stub_insns[i])))
+			return 0;
+	}
+
+	if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) {
+		/* Stub uses address relative to itself! */
+		reladdr = 0 + offsetof(struct ppc64_stub_entry, funcdata);
+		BUILD_BUG_ON(reladdr != 32);
+		if (reladdr > 0x1FFFFFFFFL || reladdr < -0x200000000L) {
+			pr_err("%s: Address of %p out of range of 34-bit relative address.\n",
+				me->name, (void *)reladdr);
+			return 0;
+		}
+		pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr);
+
+		/* May not even need this if we're relative to 0 */
+		if (patch_instruction(&entry->jump[0],
+		    ppc_inst_prefix(entry->jump[0] | IMM_H18(reladdr),
+				    entry->jump[1] | IMM_L(reladdr))))
+			return 0;
+
+	} else {
+		/* Stub uses address relative to r2. */
+		reladdr = (unsigned long)entry - my_r2(sechdrs, me);
+		if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
+			pr_err("%s: Address %p of stub out of range of %p.\n",
+			       me->name, (void *)reladdr, (void *)my_r2);
+			return 0;
+		}
+		pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr);
+
+		if (patch_instruction(&entry->jump[0],
+				      ppc_inst(entry->jump[0] | PPC_HA(reladdr))))
+			return 0;
+
+		if (patch_instruction(&entry->jump[1],
+				      ppc_inst(entry->jump[1] | PPC_LO(reladdr))))
+			return 0;
+	}
+
+	// func_desc_t is 8 bytes if ABIv2, else 16 bytes
+	desc = func_desc(addr);
+	for (i = 0; i < sizeof(func_desc_t) / sizeof(u32); i++) {
+		if (patch_instruction(((u32 *)&entry->funcdata) + i,
+				      ppc_inst(((u32 *)(&desc))[i])))
+			return 0;
+	}
+
+	if (patch_instruction(&entry->magic, ppc_inst(STUB_MAGIC)))
+		return 0;
+
+	return 1;
+}
+
+/* Create stub to jump to function described in this OPD/ptr: we need the
+   stub to set up the TOC ptr (r2) for the function. */
+static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs,
+				   unsigned long addr,
+				   struct module *me,
+				   const char *name)
+{
+	struct ppc64_stub_entry *stubs;
+	unsigned int i, num_stubs;
+
+	num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs);
+
+	/* Find this stub, or if that fails, the next avail. entry */
+	stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr;
+	for (i = 0; stub_func_addr(stubs[i].funcdata); i++) {
+		if (WARN_ON(i >= num_stubs))
+			return 0;
+
+		if (stub_func_addr(stubs[i].funcdata) == func_addr(addr))
+			return (unsigned long)&stubs[i];
+	}
+
+	if (!create_stub(sechdrs, &stubs[i], addr, me, name))
+		return 0;
+
+	return (unsigned long)&stubs[i];
+}
+
+#ifdef CONFIG_PPC_KERNEL_PCREL
+/* Create GOT to load the location described in this ptr */
+static unsigned long got_for_addr(const Elf64_Shdr *sechdrs,
+				  unsigned long addr,
+				  struct module *me,
+				  const char *name)
+{
+	struct ppc64_got_entry *got;
+	unsigned int i, num_got;
+
+	if (!IS_ENABLED(CONFIG_PPC_KERNEL_PCREL))
+		return addr;
+
+	num_got = sechdrs[me->arch.got_section].sh_size / sizeof(*got);
+
+	/* Find this stub, or if that fails, the next avail. entry */
+	got = (void *)sechdrs[me->arch.got_section].sh_addr;
+	for (i = 0; got[i].addr; i++) {
+		if (WARN_ON(i >= num_got))
+			return 0;
+
+		if (got[i].addr == addr)
+			return (unsigned long)&got[i];
+	}
+
+	got[i].addr = addr;
+
+	return (unsigned long)&got[i];
+}
+#endif
+
+/* We expect a noop next: if it is, replace it with instruction to
+   restore r2. */
+static int restore_r2(const char *name, u32 *instruction, struct module *me)
+{
+	u32 *prev_insn = instruction - 1;
+	u32 insn_val = *instruction;
+
+	if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL))
+		return 0;
+
+	if (is_mprofile_ftrace_call(name))
+		return 0;
+
+	/*
+	 * Make sure the branch isn't a sibling call.  Sibling calls aren't
+	 * "link" branches and they don't return, so they don't need the r2
+	 * restore afterwards.
+	 */
+	if (!instr_is_relative_link_branch(ppc_inst(*prev_insn)))
+		return 0;
+
+	/*
+	 * For livepatch, the restore r2 instruction might have already been
+	 * written previously, if the referenced symbol is in a previously
+	 * unloaded module which is now being loaded again.  In that case, skip
+	 * the warning and the instruction write.
+	 */
+	if (insn_val == PPC_INST_LD_TOC)
+		return 0;
+
+	if (insn_val != PPC_RAW_NOP()) {
+		pr_err("%s: Expected nop after call, got %08x at %pS\n",
+			me->name, insn_val, instruction);
+		return -ENOEXEC;
+	}
+
+	/* ld r2,R2_STACK_OFFSET(r1) */
+	return patch_instruction(instruction, ppc_inst(PPC_INST_LD_TOC));
+}
+
+int apply_relocate_add(Elf64_Shdr *sechdrs,
+		       const char *strtab,
+		       unsigned int symindex,
+		       unsigned int relsec,
+		       struct module *me)
+{
+	unsigned int i;
+	Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr;
+	Elf64_Sym *sym;
+	unsigned long *location;
+	unsigned long value;
+
+	pr_debug("Applying ADD relocate section %u to %u\n", relsec,
+	       sechdrs[relsec].sh_info);
+
+#ifndef CONFIG_PPC_KERNEL_PCREL
+	/* First time we're called, we can fix up .TOC. */
+	if (!me->arch.toc_fixed) {
+		sym = find_dot_toc(sechdrs, strtab, symindex);
+		/* It's theoretically possible that a module doesn't want a
+		 * .TOC. so don't fail it just for that. */
+		if (sym)
+			sym->st_value = my_r2(sechdrs, me);
+		me->arch.toc_fixed = true;
+	}
+#endif
+	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
+		/* This is where to make the change */
+		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+			+ rela[i].r_offset;
+		/* This is the symbol it is referring to */
+		sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
+			+ ELF64_R_SYM(rela[i].r_info);
+
+		pr_debug("RELOC at %p: %li-type as %s (0x%lx) + %li\n",
+		       location, (long)ELF64_R_TYPE(rela[i].r_info),
+		       strtab + sym->st_name, (unsigned long)sym->st_value,
+		       (long)rela[i].r_addend);
+
+		/* `Everything is relative'. */
+		value = sym->st_value + rela[i].r_addend;
+
+		switch (ELF64_R_TYPE(rela[i].r_info)) {
+		case R_PPC64_ADDR32:
+			/* Simply set it */
+			*(u32 *)location = value;
+			break;
+
+		case R_PPC64_ADDR64:
+			/* Simply set it */
+			*(unsigned long *)location = value;
+			break;
+
+#ifndef CONFIG_PPC_KERNEL_PCREL
+		case R_PPC64_TOC:
+			*(unsigned long *)location = my_r2(sechdrs, me);
+			break;
+
+		case R_PPC64_TOC16:
+			/* Subtract TOC pointer */
+			value -= my_r2(sechdrs, me);
+			if (value + 0x8000 > 0xffff) {
+				pr_err("%s: bad TOC16 relocation (0x%lx)\n",
+				       me->name, value);
+				return -ENOEXEC;
+			}
+			*((uint16_t *) location)
+				= (*((uint16_t *) location) & ~0xffff)
+				| (value & 0xffff);
+			break;
+
+		case R_PPC64_TOC16_LO:
+			/* Subtract TOC pointer */
+			value -= my_r2(sechdrs, me);
+			*((uint16_t *) location)
+				= (*((uint16_t *) location) & ~0xffff)
+				| (value & 0xffff);
+			break;
+
+		case R_PPC64_TOC16_DS:
+			/* Subtract TOC pointer */
+			value -= my_r2(sechdrs, me);
+			if ((value & 3) != 0 || value + 0x8000 > 0xffff) {
+				pr_err("%s: bad TOC16_DS relocation (0x%lx)\n",
+				       me->name, value);
+				return -ENOEXEC;
+			}
+			*((uint16_t *) location)
+				= (*((uint16_t *) location) & ~0xfffc)
+				| (value & 0xfffc);
+			break;
+
+		case R_PPC64_TOC16_LO_DS:
+			/* Subtract TOC pointer */
+			value -= my_r2(sechdrs, me);
+			if ((value & 3) != 0) {
+				pr_err("%s: bad TOC16_LO_DS relocation (0x%lx)\n",
+				       me->name, value);
+				return -ENOEXEC;
+			}
+			*((uint16_t *) location)
+				= (*((uint16_t *) location) & ~0xfffc)
+				| (value & 0xfffc);
+			break;
+
+		case R_PPC64_TOC16_HA:
+			/* Subtract TOC pointer */
+			value -= my_r2(sechdrs, me);
+			value = ((value + 0x8000) >> 16);
+			*((uint16_t *) location)
+				= (*((uint16_t *) location) & ~0xffff)
+				| (value & 0xffff);
+			break;
+#endif
+
+		case R_PPC_REL24:
+#ifdef CONFIG_PPC_KERNEL_PCREL
+		/* PCREL still generates REL24 for mcount */
+		case R_PPC64_REL24_NOTOC:
+#endif
+			/* FIXME: Handle weak symbols here --RR */
+			if (sym->st_shndx == SHN_UNDEF ||
+			    sym->st_shndx == SHN_LIVEPATCH) {
+				/* External: go via stub */
+				value = stub_for_addr(sechdrs, value, me,
+						strtab + sym->st_name);
+				if (!value)
+					return -ENOENT;
+				if (restore_r2(strtab + sym->st_name,
+					       (u32 *)location + 1, me))
+					return -ENOEXEC;
+			} else
+				value += local_entry_offset(sym);
+
+			/* Convert value to relative */
+			value -= (unsigned long)location;
+			if (value + 0x2000000 > 0x3ffffff || (value & 3) != 0){
+				pr_err("%s: REL24 %li out of range!\n",
+				       me->name, (long int)value);
+				return -ENOEXEC;
+			}
+
+			/* Only replace bits 2 through 26 */
+			value = (*(uint32_t *)location & ~PPC_LI_MASK) | PPC_LI(value);
+
+			if (patch_instruction((u32 *)location, ppc_inst(value)))
+				return -EFAULT;
+
+			break;
+
+		case R_PPC64_REL64:
+			/* 64 bits relative (used by features fixups) */
+			*location = value - (unsigned long)location;
+			break;
+
+		case R_PPC64_REL32:
+			/* 32 bits relative (used by relative exception tables) */
+			/* Convert value to relative */
+			value -= (unsigned long)location;
+			if (value + 0x80000000 > 0xffffffff) {
+				pr_err("%s: REL32 %li out of range!\n",
+				       me->name, (long int)value);
+				return -ENOEXEC;
+			}
+			*(u32 *)location = value;
+			break;
+
+#ifdef CONFIG_PPC_KERNEL_PCREL
+		case R_PPC64_PCREL34: {
+			unsigned long absvalue = value;
+
+			/* Convert value to relative */
+			value -= (unsigned long)location;
+
+			if (value + 0x200000000 > 0x3ffffffff) {
+				if (sym->st_shndx != me->arch.pcpu_section) {
+					pr_err("%s: REL34 %li out of range!\n",
+					       me->name, (long)value);
+					return -ENOEXEC;
+				}
+
+				/*
+				 * per-cpu section is special cased because
+				 * it is moved during loading, so has to be
+				 * converted to use GOT.
+				 */
+				value = got_for_addr(sechdrs, absvalue, me,
+						     strtab + sym->st_name);
+				if (!value)
+					return -ENOENT;
+				value -= (unsigned long)location;
+
+				/* Turn pla into pld */
+				if (patch_instruction((u32 *)location,
+				    ppc_inst_prefix((*(u32 *)location & ~0x02000000),
+						    (*((u32 *)location + 1) & ~0xf8000000) | 0xe4000000)))
+					return -EFAULT;
+			}
+
+			if (patch_instruction((u32 *)location,
+			    ppc_inst_prefix((*(u32 *)location & ~0x3ffff) | IMM_H18(value),
+					    (*((u32 *)location + 1) & ~0xffff) | IMM_L(value))))
+				return -EFAULT;
+
+			break;
+		}
+
+#else
+		case R_PPC64_TOCSAVE:
+			/*
+			 * Marker reloc indicates we don't have to save r2.
+			 * That would only save us one instruction, so ignore
+			 * it.
+			 */
+			break;
+#endif
+
+		case R_PPC64_ENTRY:
+			if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL))
+				break;
+
+			/*
+			 * Optimize ELFv2 large code model entry point if
+			 * the TOC is within 2GB range of current location.
+			 */
+			value = my_r2(sechdrs, me) - (unsigned long)location;
+			if (value + 0x80008000 > 0xffffffff)
+				break;
+			/*
+			 * Check for the large code model prolog sequence:
+		         *	ld r2, ...(r12)
+			 *	add r2, r2, r12
+			 */
+			if ((((uint32_t *)location)[0] & ~0xfffc) != PPC_RAW_LD(_R2, _R12, 0))
+				break;
+			if (((uint32_t *)location)[1] != PPC_RAW_ADD(_R2, _R2, _R12))
+				break;
+			/*
+			 * If found, replace it with:
+			 *	addis r2, r12, (.TOC.-func)@ha
+			 *	addi  r2,  r2, (.TOC.-func)@l
+			 */
+			((uint32_t *)location)[0] = PPC_RAW_ADDIS(_R2, _R12, PPC_HA(value));
+			((uint32_t *)location)[1] = PPC_RAW_ADDI(_R2, _R2, PPC_LO(value));
+			break;
+
+		case R_PPC64_REL16_HA:
+			/* Subtract location pointer */
+			value -= (unsigned long)location;
+			value = ((value + 0x8000) >> 16);
+			*((uint16_t *) location)
+				= (*((uint16_t *) location) & ~0xffff)
+				| (value & 0xffff);
+			break;
+
+		case R_PPC64_REL16_LO:
+			/* Subtract location pointer */
+			value -= (unsigned long)location;
+			*((uint16_t *) location)
+				= (*((uint16_t *) location) & ~0xffff)
+				| (value & 0xffff);
+			break;
+
+#ifdef CONFIG_PPC_KERNEL_PCREL
+		case R_PPC64_GOT_PCREL34:
+			value = got_for_addr(sechdrs, value, me,
+					     strtab + sym->st_name);
+			if (!value)
+				return -ENOENT;
+			value -= (unsigned long)location;
+			((uint32_t *)location)[0] = (((uint32_t *)location)[0] & ~0x3ffff) |
+						    ((value >> 16) & 0x3ffff);
+			((uint32_t *)location)[1] = (((uint32_t *)location)[1] & ~0xffff) |
+						    (value & 0xffff);
+			break;
+#endif
+
+		default:
+			pr_err("%s: Unknown ADD relocation: %lu\n",
+			       me->name,
+			       (unsigned long)ELF64_R_TYPE(rela[i].r_info));
+			return -ENOEXEC;
+		}
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+int module_trampoline_target(struct module *mod, unsigned long addr,
+			     unsigned long *target)
+{
+	struct ppc64_stub_entry *stub;
+	func_desc_t funcdata;
+	u32 magic;
+
+	if (!within_module_core(addr, mod)) {
+		pr_err("%s: stub %lx not in module %s\n", __func__, addr, mod->name);
+		return -EFAULT;
+	}
+
+	stub = (struct ppc64_stub_entry *)addr;
+
+	if (copy_from_kernel_nofault(&magic, &stub->magic,
+			sizeof(magic))) {
+		pr_err("%s: fault reading magic for stub %lx for %s\n", __func__, addr, mod->name);
+		return -EFAULT;
+	}
+
+	if (magic != STUB_MAGIC) {
+		pr_err("%s: bad magic for stub %lx for %s\n", __func__, addr, mod->name);
+		return -EFAULT;
+	}
+
+	if (copy_from_kernel_nofault(&funcdata, &stub->funcdata,
+			sizeof(funcdata))) {
+		pr_err("%s: fault reading funcdata for stub %lx for %s\n", __func__, addr, mod->name);
+                return -EFAULT;
+	}
+
+	*target = stub_func_addr(funcdata);
+
+	return 0;
+}
+
+int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs)
+{
+	mod->arch.tramp = stub_for_addr(sechdrs,
+					(unsigned long)ftrace_caller,
+					mod,
+					"ftrace_caller");
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+	mod->arch.tramp_regs = stub_for_addr(sechdrs,
+					(unsigned long)ftrace_regs_caller,
+					mod,
+					"ftrace_regs_caller");
+	if (!mod->arch.tramp_regs)
+		return -ENOENT;
+#endif
+
+	if (!mod->arch.tramp)
+		return -ENOENT;
+
+	return 0;
+}
+#endif