The perf_sample_regs_user function now returns result of the user
register retrieval, which simplifies surrounding code a bit.
The perf_output_sample_ustack now combines initial dump size
output for both (stack dump un/available) cases.
Cc: Frederic Weisbecker <fweis...@gmail.com>
Cc: Ingo Molnar <mi...@elte.hu>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Signed-off-by: Jiri Olsa <jo...@redhat.com>
---
kernel/events/core.c | 64 ++++++++++++++++++++++++-------------------------
1 files changed, 31 insertions(+), 33 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 71329d6..e392dcb 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3783,11 +3783,15 @@ perf_output_sample_regs(struct perf_output_handle
*handle,
__weak void
arch_sample_regs_user_fixup(struct perf_regs_user *regs_user, int kernel) { }
-static void perf_sample_regs_user(struct perf_regs_user *regs_user,
+static int perf_sample_regs_user(struct perf_regs_user *regs_user,
struct pt_regs *regs)
{
int kernel = !user_mode(regs);
+ /* Already defined. */
+ if (regs_user->abi)
+ return 1;
+
if (kernel) {
if (current->mm)
regs = task_pt_regs(current);
@@ -3800,6 +3804,8 @@ static void perf_sample_regs_user(struct perf_regs_user
*regs_user,
regs_user->abi = perf_reg_abi(current);
arch_sample_regs_user_fixup(regs_user, kernel);
}
+
+ return regs ? 1 : 0;
}
/*
@@ -3825,10 +3831,6 @@ perf_sample_ustack_size(u16 stack_size, u16 header_size,
{
u64 task_size;
- /* No regs, no stack pointer, no dump. */
- if (!regs)
- return 0;
-
/*
* Check if we fit in with the requested stack size into the:
* - TASK_SIZE
@@ -3862,29 +3864,26 @@ static void
perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
struct pt_regs *regs)
{
- /* Case of a kernel thread, nothing to dump */
- if (!regs) {
- u64 size = 0;
- perf_output_put(handle, size);
- } else {
+ /*
+ * We dump:
+ * static size
+ * - the size requested by user or the best one we can fit
+ * in to the sample max size
+ * - zero (and final data) if there's nothing to dump
+ * data
+ * - user stack dump data
+ * dynamic size
+ * - the actual dumped size
+ */
+
+ /* Static size. */
+ perf_output_put(handle, dump_size);
+
+ if (dump_size) {
unsigned long sp;
unsigned int rem;
u64 dyn_size;
- /*
- * We dump:
- * static size
- * - the size requested by user or the best one we can fit
- * in to the sample max size
- * data
- * - user stack dump data
- * dynamic size
- * - the actual dumped size
- */
-
- /* Static size. */
- perf_output_put(handle, dump_size);
-
/* Data. */
sp = perf_user_stack_pointer(regs);
rem = __output_copy_user(handle, (void *) sp, dump_size);
@@ -4235,9 +4234,7 @@ void perf_prepare_sample(struct perf_event_header *header,
/* regs dump ABI info */
int size = sizeof(u64);
- perf_sample_regs_user(&data->regs_user, regs);
-
- if (data->regs_user.regs) {
+ if (perf_sample_regs_user(&data->regs_user, regs)) {
u64 mask = event->attr.sample_regs_user;
size += hweight64(mask) * sizeof(u64);
}
@@ -4253,14 +4250,15 @@ void perf_prepare_sample(struct perf_event_header
*header,
* up the rest of the sample size.
*/
struct perf_regs_user *uregs = &data->regs_user;
- u16 stack_size = event->attr.sample_stack_user;
+ u64 sample_stack_user = event->attr.sample_stack_user;
+ u16 stack_size = 0;
u16 size = sizeof(u64);
- if (!uregs->abi)
- perf_sample_regs_user(uregs, regs);
-
- stack_size = perf_sample_ustack_size(stack_size, header->size,
- uregs->regs);
+ if (perf_sample_regs_user(uregs, regs)) {
+ stack_size = perf_sample_ustack_size(sample_stack_user,
+ header->size,
+ uregs->regs);
+ }
/*
* If there is something to dump, add space for the dump
--
1.7.7.6
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