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Subject[PATCH 18/23] perf annotate-data: Track instructions with a this-cpu variable
Date
Like global variables, this per-cpu variables should be tracked
correctly. Factor our get_global_var_type() to handle both global
and per-cpu (for this cpu) variables in the same manner.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
tools/perf/util/annotate-data.c | 31 ++++++++++++++++++++++++++++++-
1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c
index d57622ddd5d3..48fea0c716ef 100644
--- a/tools/perf/util/annotate-data.c
+++ b/tools/perf/util/annotate-data.c
@@ -553,12 +553,41 @@ static void update_insn_state_x86(struct type_state *state,
fbreg = -1;
}

- /* Case 1. register to register transfers */
+ /* Case 1. register to register or segment:offset to register transfers */
if (!src->mem_ref && !dst->mem_ref) {
if (!has_reg_type(state, dst->reg1))
return;

tsr = &state->regs[dst->reg1];
+ if (map__dso(dloc->ms->map)->kernel &&
+ src->segment == INSN_SEG_X86_GS && src->imm) {
+ u64 ip = dloc->ms->sym->start + dl->al.offset;
+ u64 var_addr;
+ int offset;
+
+ /*
+ * In kernel, %gs points to a per-cpu region for the
+ * current CPU. Access with a constant offset should
+ * be treated as a global variable access.
+ */
+ var_addr = src->offset;
+
+ if (!get_global_var_type(cu_die, dloc, ip, var_addr,
+ &offset, &type_die) ||
+ !die_get_member_type(&type_die, offset, &type_die)) {
+ tsr->ok = false;
+ return;
+ }
+
+ tsr->type = type_die;
+ tsr->ok = true;
+
+ pr_debug_dtp("mov [%x] this-cpu addr=%#"PRIx64" -> reg%d",
+ insn_offset, var_addr, dst->reg1);
+ pr_debug_type_name(&tsr->type);
+ return;
+ }
+
if (!has_reg_type(state, src->reg1) ||
!state->regs[src->reg1].ok) {
tsr->ok = false;
--
2.44.0.291.gc1ea87d7ee-goog

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