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Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Browse Source 
Pull misc fixes from Ingo Molnar:
 "A CPU hotplug debuggability fix and three objtool false positive
  warnings fixes for new GCC6 code generation patterns"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  cpu/hotplug: Use distinct name for cpu_hotplug.dep_map
  objtool: Skip all "unreachable instruction" warnings for gcov kernels
  objtool: Improve rare switch jump table pattern detection
  objtool: Support '-mtune=atom' stack frame setup instruction
This commit is contained in:
Linus Torvalds 2016-10-18 08:35:07 -07:00
commit 351267d941
3 changed files with 45 additions and 34 deletions
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2
kernel/cpu.c
View File

@ -228,7 +228,7 @@ static struct {
.wq = __WAIT_QUEUE_HEAD_INITIALIZER(cpu_hotplug.wq),
.lock = __MUTEX_INITIALIZER(cpu_hotplug.lock),
#ifdef CONFIG_DEBUG_LOCK_ALLOC
.dep_map = {.name = "cpu_hotplug.lock" },
.dep_map = STATIC_LOCKDEP_MAP_INIT("cpu_hotplug.dep_map", &cpu_hotplug.dep_map),
#endif
};

9
tools/objtool/arch/x86/decode.c
View File

@ -98,6 +98,15 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
*type = INSN_FP_SETUP;
break;
case 0x8d:
if (insn.rex_prefix.bytes &&
insn.rex_prefix.bytes[0] == 0x48 &&
insn.modrm.nbytes && insn.modrm.bytes[0] == 0x2c &&
insn.sib.nbytes && insn.sib.bytes[0] == 0x24)
/* lea %(rsp), %rbp */
*type = INSN_FP_SETUP;
break;
case 0x90:
*type = INSN_NOP;
break;

68
tools/objtool/builtin-check.c
View File

@ -97,6 +97,19 @@ static struct instruction *next_insn_same_sec(struct objtool_file *file,
return next;
}
static bool gcov_enabled(struct objtool_file *file)
{
struct section *sec;
struct symbol *sym;
list_for_each_entry(sec, &file->elf->sections, list)
list_for_each_entry(sym, &sec->symbol_list, list)
if (!strncmp(sym->name, "__gcov_.", 8))
return true;
return false;
}
#define for_each_insn(file, insn) \
list_for_each_entry(insn, &file->insn_list, list)
@ -713,6 +726,7 @@ static struct rela *find_switch_table(struct objtool_file *file,
struct instruction *insn)
{
struct rela *text_rela, *rodata_rela;
struct instruction *orig_insn = insn;
text_rela = find_rela_by_dest_range(insn->sec, insn->offset, insn->len);
if (text_rela && text_rela->sym == file->rodata->sym) {
@ -733,10 +747,16 @@ static struct rela *find_switch_table(struct objtool_file *file,
/* case 3 */
func_for_each_insn_continue_reverse(file, func, insn) {
if (insn->type == INSN_JUMP_UNCONDITIONAL ||
insn->type == INSN_JUMP_DYNAMIC)
if (insn->type == INSN_JUMP_DYNAMIC)
break;
/* allow small jumps within the range */
if (insn->type == INSN_JUMP_UNCONDITIONAL &&
insn->jump_dest &&
(insn->jump_dest->offset <= insn->offset ||
insn->jump_dest->offset >= orig_insn->offset))
break;
text_rela = find_rela_by_dest_range(insn->sec, insn->offset,
insn->len);
if (text_rela && text_rela->sym == file->rodata->sym)
@ -1034,34 +1054,6 @@ static int validate_branch(struct objtool_file *file,
return 0;
}
static bool is_gcov_insn(struct instruction *insn)
{
struct rela *rela;
struct section *sec;
struct symbol *sym;
unsigned long offset;
rela = find_rela_by_dest_range(insn->sec, insn->offset, insn->len);
if (!rela)
return false;
if (rela->sym->type != STT_SECTION)
return false;
sec = rela->sym->sec;
offset = rela->addend + insn->offset + insn->len - rela->offset;
list_for_each_entry(sym, &sec->symbol_list, list) {
if (sym->type != STT_OBJECT)
continue;
if (offset >= sym->offset && offset < sym->offset + sym->len)
return (!memcmp(sym->name, "__gcov0.", 8));
}
return false;
}
static bool is_kasan_insn(struct instruction *insn)
{
return (insn->type == INSN_CALL &&
@ -1083,9 +1075,6 @@ static bool ignore_unreachable_insn(struct symbol *func,
if (insn->type == INSN_NOP)
return true;
if (is_gcov_insn(insn))
return true;
/*
* Check if this (or a subsequent) instruction is related to
* CONFIG_UBSAN or CONFIG_KASAN.
@ -1146,6 +1135,19 @@ static int validate_functions(struct objtool_file *file)
ignore_unreachable_insn(func, insn))
continue;
/*
* gcov produces a lot of unreachable
* instructions. If we get an unreachable
* warning and the file has gcov enabled, just
* ignore it, and all other such warnings for
* the file.
*/
if (!file->ignore_unreachables &&
gcov_enabled(file)) {
file->ignore_unreachables = true;
continue;
}
WARN_FUNC("function has unreachable instruction", insn->sec, insn->offset);
warnings++;
}