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create-diff-object: fix ppc64le static local variable correlation

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On ppc64le, the static local variable correlation doesn't take into
account the .toc rela indirection for data references, meaning that it's
basically broken in many cases.

Fix it by making the code .toc-aware.

Fixes #793.

Reported-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
This commit is contained in:
Josh Poimboeuf 2018-04-04 16:24:15 -05:00
parent 55650e16af
commit ff8b2510af
1 changed files with 24 additions and 16 deletions
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40
kpatch-build/create-diff-object.c
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@ -147,6 +147,16 @@ static int is_gcc6_localentry_bundled_sym(struct symbol *sym)
}
#endif
static struct rela *toc_rela(const struct rela *rela)
{
if (rela->type != R_PPC64_TOC16_HA &&
rela->type != R_PPC64_TOC16_LO_DS)
return (struct rela *)rela;
/* Will return NULL for .toc constant entries */
return find_rela_by_offset(rela->sym->sec->rela, rela->addend);
}
/*
* When compiling with -ffunction-sections and -fdata-sections, almost every
* symbol gets its own dedicated section. We call such symbols "bundled"
@ -854,7 +864,7 @@ static char *kpatch_section_function_name(struct section *sec)
static struct symbol *kpatch_find_static_twin(struct section *sec,
struct symbol *sym)
{
struct rela *rela;
struct rela *rela, *rela_toc;
if (!sec->twin)
return NULL;
@ -862,13 +872,17 @@ static struct symbol *kpatch_find_static_twin(struct section *sec,
/* find the patched object's corresponding variable */
list_for_each_entry(rela, &sec->twin->relas, list) {
if (rela->sym->twin)
rela_toc = toc_rela(rela);
if (!rela_toc)
continue; /* skip toc constants */
if (rela_toc->sym->twin)
continue;
if (kpatch_mangled_strcmp(rela->sym->name, sym->name))
if (kpatch_mangled_strcmp(rela_toc->sym->name, sym->name))
continue;
return rela->sym;
return rela_toc->sym;
}
return NULL;
@ -957,12 +971,16 @@ static void kpatch_correlate_static_local_variables(struct kpatch_elf *base,
list_for_each_entry(sec, &base->sections, list) {
if (!is_rela_section(sec) ||
is_debug_section(sec))
is_debug_section(sec) ||
!strcmp(sec->name, ".rela.toc"))
continue;
list_for_each_entry(rela, &sec->relas, list) {
sym = rela->sym;
if (!toc_rela(rela))
continue; /* skip toc constants */
sym = toc_rela(rela)->sym;
if (!kpatch_is_normal_static_local(sym))
continue;
@ -2365,16 +2383,6 @@ static int kpatch_is_core_module_symbol(char *name)
!strcmp(name, "kpatch_shadow_get"));
}
static struct rela *toc_rela(const struct rela *rela)
{
if (rela->type != R_PPC64_TOC16_HA &&
rela->type != R_PPC64_TOC16_LO_DS)
return (struct rela *)rela;
/* Will return NULL for .toc constant entries */
return find_rela_by_offset(rela->sym->sec->rela, rela->addend);
}
/*
* If the patched code refers to a symbol, for example, calls a function
* or stores a pointer to a function somewhere, the address of that symbol