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perf annotate-data: Add stack canary type

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When the stack protector is enabled, compiler would generate code to
check stack overflow with a special value called 'stack carary' at
runtime.  On x86_64, GCC hard-codes the stack canary as %gs:40.

While there's a definition of fixed_percpu_data in asm/processor.h,
it seems that the header is not included everywhere and many places
it cannot find the type info.  As it's in the well-known location (at
%gs:40), let's add a pseudo stack canary type to handle it specially.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20240319055115.4063940-22-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim
2024-03-18 22:51:13 -07:00
committed by Arnaldo Carvalho de Melo
parent eb9190afae
commit b3c95109c1
3 changed files with 72 additions and 0 deletions
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46
tools/perf/util/annotate-data.c
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@@ -30,6 +30,7 @@ enum type_state_kind {
TSR_KIND_PERCPU_BASE,
TSR_KIND_CONST,
TSR_KIND_POINTER,
TSR_KIND_CANARY,
};
#define pr_debug_dtp(fmt, ...) \
@@ -62,6 +63,9 @@ static void pr_debug_type_name(Dwarf_Die *die, enum type_state_kind kind)
pr_info(" pointer");
/* it also prints the type info */
break;
case TSR_KIND_CANARY:
pr_info(" stack canary\n");
return;
case TSR_KIND_TYPE:
default:
break;
@@ -676,6 +680,15 @@ static void update_insn_state_x86(struct type_state *state,
*/
var_addr = src->offset;
if (var_addr == 40) {
tsr->kind = TSR_KIND_CANARY;
tsr->ok = true;
pr_debug_dtp("mov [%x] stack canary -> reg%d\n",
insn_offset, dst->reg1);
return;
}
if (!get_global_var_type(cu_die, dloc, ip, var_addr,
&offset, &type_die) ||
!die_get_member_type(&type_die, offset, &type_die)) {
@@ -991,6 +1004,16 @@ static void delete_var_types(struct die_var_type *var_types)
}
}
/* should match to is_stack_canary() in util/annotate.c */
static void setup_stack_canary(struct data_loc_info *dloc)
{
if (arch__is(dloc->arch, "x86")) {
dloc->op->segment = INSN_SEG_X86_GS;
dloc->op->imm = true;
dloc->op->offset = 40;
}
}
/* It's at the target address, check if it has a matching type */
static bool check_matching_type(struct type_state *state,
struct data_loc_info *dloc, int reg,
@@ -1038,6 +1061,11 @@ static bool check_matching_type(struct type_state *state,
if (stack == NULL)
return false;
if (stack->kind == TSR_KIND_CANARY) {
setup_stack_canary(dloc);
return false;
}
*type_die = stack->type;
/* Update the type offset from the start of slot */
dloc->type_offset -= stack->offset;
@@ -1062,6 +1090,11 @@ static bool check_matching_type(struct type_state *state,
if (stack == NULL)
return false;
if (stack->kind == TSR_KIND_CANARY) {
setup_stack_canary(dloc);
return false;
}
*type_die = stack->type;
/* Update the type offset from the start of slot */
dloc->type_offset -= fboff + stack->offset;
@@ -1102,6 +1135,19 @@ static bool check_matching_type(struct type_state *state,
return true;
}
if (state->regs[reg].ok && state->regs[reg].kind == TSR_KIND_CANARY) {
pr_debug_dtp(" stack canary\n");
/*
* This is a saved value of the stack canary which will be handled
* in the outer logic when it returns failure here. Pretend it's
* from the stack canary directly.
*/
setup_stack_canary(dloc);
return false;
}
if (map__dso(dloc->ms->map)->kernel && arch__is(dloc->arch, "x86")) {
u64 addr;
int offset;