@@ -790,7 +790,7 @@ static void delete_var_types(struct die_var_type *var_types)
/* 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,
- Dwarf_Die *type_die)
+ Dwarf_Die *cu_die, Dwarf_Die *type_die)
{
Dwarf_Word size;
u32 insn_offset = dloc->ip - dloc->ms->sym->start;
@@ -864,6 +864,23 @@ static bool check_matching_type(struct type_state *state,
return true;
}
+ if (map__dso(dloc->ms->map)->kernel && arch__is(dloc->arch, "x86")) {
+ u64 addr;
+ int offset;
+
+ if (dloc->op->segment == INSN_SEG_X86_GS && dloc->op->imm) {
+ pr_debug_dtp(" this-cpu var\n");
+
+ addr = dloc->op->offset;
+
+ if (get_global_var_type(cu_die, dloc, dloc->ip, addr,
+ &offset, type_die)) {
+ dloc->type_offset = offset;
+ return true;
+ }
+ }
+ }
+
pr_debug_dtp("\n");
return false;
}
@@ -897,7 +914,7 @@ static bool find_data_type_insn(struct data_loc_info *dloc, int reg,
if (this_ip == dloc->ip) {
found = check_matching_type(&state, dloc, reg,
- type_die);
+ cu_die, type_die);
goto out;
}
@@ -3921,6 +3921,13 @@ struct annotated_data_type *hist_entry__get_data_type(struct hist_entry *he)
op_loc->offset, dl);
}
+ /* This CPU access in kernel - pretend PC-relative addressing */
+ if (map__dso(ms->map)->kernel && arch__is(arch, "x86") &&
+ op_loc->segment == INSN_SEG_X86_GS && op_loc->imm) {
+ dloc.var_addr = op_loc->offset;
+ op_loc->reg1 = DWARF_REG_PC;
+ }
+
mem_type = find_data_type(&dloc);
if (mem_type)
istat->good++;
On x86, the kernel gets the current task using the current macro like below: #define current get_current() static __always_inline struct task_struct *get_current(void) { return this_cpu_read_stable(pcpu_hot.current_task); } So it returns the current_task field of struct pcpu_hot which is the first member. On my build, it's located at 0x32940. $ nm vmlinux | grep pcpu_hot 0000000000032940 D pcpu_hot And the current macro generates the instructions like below: mov %gs:0x32940, %rcx So the %gs segment register points to the beginning of the per-cpu region of this cpu and it points the variable with a constant. Let's update the instruction location info to have a segment register and handle %gs in kernel to look up a global variable. Pretend it as a global variable by changing the register number to DWARF_REG_PC. Signed-off-by: Namhyung Kim <namhyung@kernel.org> --- tools/perf/util/annotate-data.c | 21 +++++++++++++++++++-- tools/perf/util/annotate.c | 7 +++++++ 2 files changed, 26 insertions(+), 2 deletions(-)