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Merge tag 'objtool-core-2021-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull objtool updates from Thomas Gleixner:

 - Improve retpoline code patching by separating it from alternatives
   which reduces memory footprint and allows to do better optimizations
   in the actual runtime patching.

 - Add proper retpoline support for x86/BPF

 - Address noinstr warnings in x86/kvm, lockdep and paravirtualization
   code

 - Add support to handle pv_opsindirect calls in the noinstr analysis

 - Classify symbols upfront and cache the result to avoid redundant
   str*cmp() invocations.

 - Add a CFI hash to reduce memory consumption which also reduces
   runtime on a allyesconfig by ~50%

 - Adjust XEN code to make objtool handling more robust and as a side
   effect to prevent text fragmentation due to placement of the
   hypercall page.

* tag 'objtool-core-2021-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits)
  bpf,x86: Respect X86_FEATURE_RETPOLINE*
  bpf,x86: Simplify computing label offsets
  x86,bugs: Unconditionally allow spectre_v2=retpoline,amd
  x86/alternative: Add debug prints to apply_retpolines()
  x86/alternative: Try inline spectre_v2=retpoline,amd
  x86/alternative: Handle Jcc __x86_indirect_thunk_\reg
  x86/alternative: Implement .retpoline_sites support
  x86/retpoline: Create a retpoline thunk array
  x86/retpoline: Move the retpoline thunk declarations to nospec-branch.h
  x86/asm: Fixup odd GEN-for-each-reg.h usage
  x86/asm: Fix register order
  x86/retpoline: Remove unused replacement symbols
  objtool,x86: Replace alternatives with .retpoline_sites
  objtool: Shrink struct instruction
  objtool: Explicitly avoid self modifying code in .altinstr_replacement
  objtool: Classify symbols
  objtool: Support pv_opsindirect calls for noinstr
  x86/xen: Rework the xen_{cpu,irq,mmu}_opsarrays
  x86/xen: Mark xen_force_evtchn_callback() noinstr
  x86/xen: Make irq_disable() noinstr
  ...
This commit is contained in:
Linus Torvalds
2021-11-01 13:24:43 -07:00
parent 595b28fb0c 87c87ecd00
commit 43aa0a195f
40 changed files with 1162 additions and 816 deletions
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84
tools/objtool/elf.c
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@@ -741,90 +741,6 @@ static int elf_add_string(struct elf *elf, struct section *strtab, char *str)
return len;
}
struct symbol *elf_create_undef_symbol(struct elf *elf, const char *name)
{
struct section *symtab, *symtab_shndx;
struct symbol *sym;
Elf_Data *data;
Elf_Scn *s;
sym = malloc(sizeof(*sym));
if (!sym) {
perror("malloc");
return NULL;
}
memset(sym, 0, sizeof(*sym));
sym->name = strdup(name);
sym->sym.st_name = elf_add_string(elf, NULL, sym->name);
if (sym->sym.st_name == -1)
return NULL;
sym->sym.st_info = GELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
// st_other 0
// st_shndx 0
// st_value 0
// st_size 0
symtab = find_section_by_name(elf, ".symtab");
if (!symtab) {
WARN("can't find .symtab");
return NULL;
}
s = elf_getscn(elf->elf, symtab->idx);
if (!s) {
WARN_ELF("elf_getscn");
return NULL;
}
data = elf_newdata(s);
if (!data) {
WARN_ELF("elf_newdata");
return NULL;
}
data->d_buf = &sym->sym;
data->d_size = sizeof(sym->sym);
data->d_align = 1;
data->d_type = ELF_T_SYM;
sym->idx = symtab->sh.sh_size / sizeof(sym->sym);
symtab->sh.sh_size += data->d_size;
symtab->changed = true;
symtab_shndx = find_section_by_name(elf, ".symtab_shndx");
if (symtab_shndx) {
s = elf_getscn(elf->elf, symtab_shndx->idx);
if (!s) {
WARN_ELF("elf_getscn");
return NULL;
}
data = elf_newdata(s);
if (!data) {
WARN_ELF("elf_newdata");
return NULL;
}
data->d_buf = &sym->sym.st_size; /* conveniently 0 */
data->d_size = sizeof(Elf32_Word);
data->d_align = 4;
data->d_type = ELF_T_WORD;
symtab_shndx->sh.sh_size += 4;
symtab_shndx->changed = true;
}
sym->sec = find_section_by_index(elf, 0);
elf_add_symbol(elf, sym);
return sym;
}
struct section *elf_create_section(struct elf *elf, const char *name,
unsigned int sh_flags, size_t entsize, int nr)
{