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kernel/arch/powerpc/kernel/module_64.c

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// 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_u32(((u32 *)&entry->funcdata) + i, ((u32 *)&desc)[i]))
return 0;
}
if (patch_u32(&entry->magic, 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
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