linux/arch/powerpc/kernel/module_64.c
Linus Torvalds 192f0f8e9d powerpc updates for 5.3
Notable changes:
 
  - Removal of the NPU DMA code, used by the out-of-tree Nvidia driver, as well
    as some other functions only used by drivers that haven't (yet?) made it
    upstream.
 
  - A fix for a bug in our handling of hardware watchpoints (eg. perf record -e
    mem: ...) which could lead to register corruption and kernel crashes.
 
  - Enable HAVE_ARCH_HUGE_VMAP, which allows us to use large pages for vmalloc
    when using the Radix MMU.
 
  - A large but incremental rewrite of our exception handling code to use gas
    macros rather than multiple levels of nested CPP macros.
 
 And the usual small fixes, cleanups and improvements.
 
 Thanks to:
   Alastair D'Silva, Alexey Kardashevskiy, Andreas Schwab, Aneesh Kumar K.V, Anju
   T Sudhakar, Anton Blanchard, Arnd Bergmann, Athira Rajeev, Cédric Le Goater,
   Christian Lamparter, Christophe Leroy, Christophe Lombard, Christoph Hellwig,
   Daniel Axtens, Denis Efremov, Enrico Weigelt, Frederic Barrat, Gautham R.
   Shenoy, Geert Uytterhoeven, Geliang Tang, Gen Zhang, Greg Kroah-Hartman, Greg
   Kurz, Gustavo Romero, Krzysztof Kozlowski, Madhavan Srinivasan, Masahiro
   Yamada, Mathieu Malaterre, Michael Neuling, Nathan Lynch, Naveen N. Rao,
   Nicholas Piggin, Nishad Kamdar, Oliver O'Halloran, Qian Cai, Ravi Bangoria,
   Sachin Sant, Sam Bobroff, Satheesh Rajendran, Segher Boessenkool, Shaokun
   Zhang, Shawn Anastasio, Stewart Smith, Suraj Jitindar Singh, Thiago Jung
   Bauermann, YueHaibing.
 -----BEGIN PGP SIGNATURE-----
 
 iQIcBAABAgAGBQJdKVoLAAoJEFHr6jzI4aWA0kIP/A6shIbbE7H5W2hFrqt/PPPK
 3+VrvPKbOFF+W6hcE/RgSZmEnUo0svdNjHUd/eMfFS1vb/uRt2QDdrsHUNNwURQL
 M2mcLXFwYpnjSjb/XMgDbHpAQxjeGfTdYLonUIejN7Rk8KQUeLyKQ3SBn6kfMc46
 DnUUcPcjuRGaETUmVuZZ4e40ZWbJp8PKDrSJOuUrTPXMaK5ciNbZk5mCWXGbYl6G
 BMQAyv4ld/417rNTjBEP/T2foMJtioAt4W6mtlgdkOTdIEZnFU67nNxDBthNSu2c
 95+I+/sML4KOp1R4yhqLSLIDDbc3bg3c99hLGij0d948z3bkSZ8bwnPaUuy70C4v
 U8rvl/+N6C6H3DgSsPE/Gnkd8DnudqWY8nULc+8p3fXljGwww6/Qgt+6yCUn8BdW
 WgixkSjKgjDmzTw8trIUNEqORrTVle7cM2hIyIK2Q5T4kWzNQxrLZ/x/3wgoYjUa
 1KwIzaRo5JKZ9D3pJnJ5U+knE2/90rJIyfcp0W6ygyJsWKi2GNmq1eN3sKOw0IxH
 Tg86RENIA/rEMErNOfP45sLteMuTR7of7peCG3yumIOZqsDVYAzerpvtSgip2cvK
 aG+9HcYlBFOOOF9Dabi8GXsTBLXLfwiyjjLSpA9eXPwW8KObgiNfTZa7ujjTPvis
 4mk9oukFTFUpfhsMmI3T
 =3dBZ
 -----END PGP SIGNATURE-----

Merge tag 'powerpc-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:
 "Notable changes:

   - Removal of the NPU DMA code, used by the out-of-tree Nvidia driver,
     as well as some other functions only used by drivers that haven't
     (yet?) made it upstream.

   - A fix for a bug in our handling of hardware watchpoints (eg. perf
     record -e mem: ...) which could lead to register corruption and
     kernel crashes.

   - Enable HAVE_ARCH_HUGE_VMAP, which allows us to use large pages for
     vmalloc when using the Radix MMU.

   - A large but incremental rewrite of our exception handling code to
     use gas macros rather than multiple levels of nested CPP macros.

  And the usual small fixes, cleanups and improvements.

  Thanks to: Alastair D'Silva, Alexey Kardashevskiy, Andreas Schwab,
  Aneesh Kumar K.V, Anju T Sudhakar, Anton Blanchard, Arnd Bergmann,
  Athira Rajeev, Cédric Le Goater, Christian Lamparter, Christophe
  Leroy, Christophe Lombard, Christoph Hellwig, Daniel Axtens, Denis
  Efremov, Enrico Weigelt, Frederic Barrat, Gautham R. Shenoy, Geert
  Uytterhoeven, Geliang Tang, Gen Zhang, Greg Kroah-Hartman, Greg Kurz,
  Gustavo Romero, Krzysztof Kozlowski, Madhavan Srinivasan, Masahiro
  Yamada, Mathieu Malaterre, Michael Neuling, Nathan Lynch, Naveen N.
  Rao, Nicholas Piggin, Nishad Kamdar, Oliver O'Halloran, Qian Cai, Ravi
  Bangoria, Sachin Sant, Sam Bobroff, Satheesh Rajendran, Segher
  Boessenkool, Shaokun Zhang, Shawn Anastasio, Stewart Smith, Suraj
  Jitindar Singh, Thiago Jung Bauermann, YueHaibing"

* tag 'powerpc-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (163 commits)
  powerpc/powernv/idle: Fix restore of SPRN_LDBAR for POWER9 stop state.
  powerpc/eeh: Handle hugepages in ioremap space
  ocxl: Update for AFU descriptor template version 1.1
  powerpc/boot: pass CONFIG options in a simpler and more robust way
  powerpc/boot: add {get, put}_unaligned_be32 to xz_config.h
  powerpc/irq: Don't WARN continuously in arch_local_irq_restore()
  powerpc/module64: Use symbolic instructions names.
  powerpc/module32: Use symbolic instructions names.
  powerpc: Move PPC_HA() PPC_HI() and PPC_LO() to ppc-opcode.h
  powerpc/module64: Fix comment in R_PPC64_ENTRY handling
  powerpc/boot: Add lzo support for uImage
  powerpc/boot: Add lzma support for uImage
  powerpc/boot: don't force gzipped uImage
  powerpc/8xx: Add microcode patch to move SMC parameter RAM.
  powerpc/8xx: Use IO accessors in microcode programming.
  powerpc/8xx: replace #ifdefs by IS_ENABLED() in microcode.c
  powerpc/8xx: refactor programming of microcode CPM params.
  powerpc/8xx: refactor printing of microcode patch name.
  powerpc/8xx: Refactor microcode write
  powerpc/8xx: refactor writing of CPM microcode arrays
  ...
2019-07-13 16:08:36 -07:00

841 lines
23 KiB
C

// 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 <asm/module.h>
#include <asm/firmware.h>
#include <asm/code-patching.h>
#include <linux/sort.h>
#include <asm/setup.h>
#include <asm/sections.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. */
#ifdef PPC64_ELF_ABI_v2
/* An address is simply the address of the function. */
typedef unsigned long func_desc_t;
static func_desc_t func_desc(unsigned long addr)
{
return addr;
}
static unsigned long func_addr(unsigned long addr)
{
return addr;
}
static unsigned long stub_func_addr(func_desc_t func)
{
return func;
}
/* 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
/* An address is address of the OPD entry, which contains address of fn. */
typedef struct ppc64_opd_entry func_desc_t;
static func_desc_t func_desc(unsigned long addr)
{
return *(struct ppc64_opd_entry *)addr;
}
static unsigned long func_addr(unsigned long addr)
{
return func_desc(addr).funcaddr;
}
static unsigned long stub_func_addr(func_desc_t func)
{
return func.funcaddr;
}
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
#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). We only
* need 6 instructions on ABIv2 but we always allocate 7 so
* so we don't have to modify the trampoline load instruction. */
u32 jump[7];
/* Used by ftrace to identify stubs */
u32 magic;
/* Data for the above code */
func_desc_t funcdata;
};
/*
* 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.
*
* For ELFv1 we need to use this to set up the new r2 value (aka TOC
* pointer). For ELFv2 it's the callee's responsibility to set up the
* new r2, but for both we need to save the old r2.
*
* We could simply patch the new r2 value and function pointer into
* the stub, but it's significantly shorter to put these values at the
* end of the stub code, and patch the stub address (32-bits relative
* to the TOC ptr, r2) into the stub.
*
* addis r11,r2, <high>
* addi r11,r11, <low>
* std r2,R2_STACK_OFFSET(r1)
* ld r12,32(r11)
* ld r2,40(r11)
* mtctr r12
* bctr
*/
static u32 ppc64_stub_insns[] = {
PPC_INST_ADDIS | __PPC_RT(R11) | __PPC_RA(R2),
PPC_INST_ADDI | __PPC_RT(R11) | __PPC_RA(R11),
/* Save current r2 value in magic place on the stack. */
PPC_INST_STD | __PPC_RS(R2) | __PPC_RA(R1) | R2_STACK_OFFSET,
PPC_INST_LD | __PPC_RT(R12) | __PPC_RA(R11) | 32,
#ifdef PPC64_ELF_ABI_v1
/* Set up new r2 from function descriptor */
PPC_INST_LD | __PPC_RT(R2) | __PPC_RA(R11) | 40,
#endif
PPC_INST_MTCTR | __PPC_RS(R12),
PPC_INST_BCTR,
};
#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 (probe_kernel_read(&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 (probe_kernel_read(&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;
}
#endif
/* Count how many different 24-bit relocations (different symbol,
different addend) */
static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num)
{
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 24-bit relocs, others don't need stubs */
if (ELF64_R_TYPE(rela[i].r_info) == R_PPC_REL24 &&
(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;
}
static void relaswap(void *_x, void *_y, int size)
{
uint64_t *x, *y, tmp;
int i;
y = (uint64_t *)_x;
x = (uint64_t *)_y;
for (i = 0; i < sizeof(Elf64_Rela) / sizeof(uint64_t); i++) {
tmp = x[i];
x[i] = y[i];
y[i] = tmp;
}
}
/* 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-funcaddr 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
* alogrithm 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, relaswap);
relocs += count_relocs((void *)sechdrs[i].sh_addr,
sechdrs[i].sh_size
/ sizeof(Elf64_Rela));
}
}
#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);
}
/* 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;
}
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++) {
char *p;
if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0)
me->arch.stubs_section = i;
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);
/* We don't handle .init for the moment: rename to _init */
while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init")))
p[0] = '_';
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);
}
if (!me->arch.stubs_section) {
pr_err("%s: doesn't contain .stubs.\n", me->name);
return -ENOEXEC;
}
/* 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;
/* Override the stubs size */
sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs);
return 0;
}
/*
* 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)
{
return (sechdrs[me->arch.toc_section].sh_addr & ~0xfful) + 0x8000;
}
/* 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)
{
long reladdr;
memcpy(entry->jump, ppc64_stub_insns, sizeof(ppc64_stub_insns));
/* 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);
entry->jump[0] |= PPC_HA(reladdr);
entry->jump[1] |= PPC_LO(reladdr);
entry->funcdata = func_desc(addr);
entry->magic = STUB_MAGIC;
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)
{
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))
return 0;
return (unsigned long)&stubs[i];
}
#ifdef CONFIG_MPROFILE_KERNEL
static bool is_mprofile_mcount_callsite(const char *name, u32 *instruction)
{
if (strcmp("_mcount", name))
return false;
/*
* Check if this is one of the -mprofile-kernel sequences.
*/
if (instruction[-1] == PPC_INST_STD_LR &&
instruction[-2] == PPC_INST_MFLR)
return true;
if (instruction[-1] == PPC_INST_MFLR)
return true;
return false;
}
/*
* In case of _mcount calls, do not save the current callee's TOC (in r2) into
* the original caller's stack frame. If we did we would clobber the saved TOC
* value of the original caller.
*/
static void squash_toc_save_inst(const char *name, unsigned long addr)
{
struct ppc64_stub_entry *stub = (struct ppc64_stub_entry *)addr;
/* Only for calls to _mcount */
if (strcmp("_mcount", name) != 0)
return;
stub->jump[2] = PPC_INST_NOP;
}
#else
static void squash_toc_save_inst(const char *name, unsigned long addr) { }
static bool is_mprofile_mcount_callsite(const char *name, u32 *instruction)
{
return false;
}
#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;
if (is_mprofile_mcount_callsite(name, prev_insn))
return 1;
/*
* 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(*prev_insn))
return 1;
if (*instruction != PPC_INST_NOP) {
pr_err("%s: Expected nop after call, got %08x at %pS\n",
me->name, *instruction, instruction);
return 0;
}
/* ld r2,R2_STACK_OFFSET(r1) */
*instruction = PPC_INST_LD_TOC;
return 1;
}
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);
/* 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;
}
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;
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;
case R_PPC_REL24:
/* 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);
if (!value)
return -ENOENT;
if (!restore_r2(strtab + sym->st_name,
(u32 *)location + 1, me))
return -ENOEXEC;
squash_toc_save_inst(strtab + sym->st_name, value);
} 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 */
*(uint32_t *)location
= (*(uint32_t *)location & ~0x03fffffc)
| (value & 0x03fffffc);
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;
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;
case R_PPC64_ENTRY:
/*
* 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_INST_LD | __PPC_RT(R2) | __PPC_RA(R12)))
break;
if (((uint32_t *)location)[1] !=
(PPC_INST_ADD | __PPC_RT(R2) | __PPC_RA(R2) | __PPC_RB(R12)))
break;
/*
* If found, replace it with:
* addis r2, r12, (.TOC.-func)@ha
* addi r2, r2, (.TOC.-func)@l
*/
((uint32_t *)location)[0] = PPC_INST_ADDIS | __PPC_RT(R2) |
__PPC_RA(R12) | PPC_HA(value);
((uint32_t *)location)[1] = PPC_INST_ADDI | __PPC_RT(R2) |
__PPC_RA(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;
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
#ifdef CONFIG_MPROFILE_KERNEL
#define PACATOC offsetof(struct paca_struct, kernel_toc)
/*
* 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 unsigned long create_ftrace_stub(const Elf64_Shdr *sechdrs,
struct module *me, unsigned long addr)
{
struct ppc64_stub_entry *entry;
unsigned int i, num_stubs;
/*
* ld r12,PACATOC(r13)
* addis r12,r12,<high>
* addi r12,r12,<low>
* mtctr r12
* bctr
*/
static u32 stub_insns[] = {
PPC_INST_LD | __PPC_RT(R12) | __PPC_RA(R13) | PACATOC,
PPC_INST_ADDIS | __PPC_RT(R12) | __PPC_RA(R12),
PPC_INST_ADDI | __PPC_RT(R12) | __PPC_RA(R12),
PPC_INST_MTCTR | __PPC_RS(R12),
PPC_INST_BCTR,
};
long reladdr;
num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*entry);
/* Find the next available stub entry */
entry = (void *)sechdrs[me->arch.stubs_section].sh_addr;
for (i = 0; i < num_stubs && stub_func_addr(entry->funcdata); i++, entry++);
if (i >= num_stubs) {
pr_err("%s: Unable to find a free slot for ftrace stub.\n", me->name);
return 0;
}
memcpy(entry->jump, stub_insns, sizeof(stub_insns));
/* 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);
/* Eventhough we don't use funcdata in the stub, it's needed elsewhere. */
entry->funcdata = func_desc(addr);
entry->magic = STUB_MAGIC;
return (unsigned long)entry;
}
#else
static unsigned long create_ftrace_stub(const Elf64_Shdr *sechdrs,
struct module *me, unsigned long addr)
{
return stub_for_addr(sechdrs, addr, me);
}
#endif
int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs)
{
mod->arch.tramp = create_ftrace_stub(sechdrs, mod,
(unsigned long)ftrace_caller);
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
mod->arch.tramp_regs = create_ftrace_stub(sechdrs, mod,
(unsigned long)ftrace_regs_caller);
if (!mod->arch.tramp_regs)
return -ENOENT;
#endif
if (!mod->arch.tramp)
return -ENOENT;
return 0;
}
#endif