Factor out perf_prepare_dump_data() so that the same logic is used for
dumping stack data as other types, such as TLS.
Slightly refactor perf_sample_ustack_size() to perf_sample_dump_size().
Move reg checks up into perf_ustack_task_size() since the task size
must now be calculated before preparing dump data.
Signed-off-by: Beau Belgrave <be...@linux.microsoft.com>
---
kernel/events/core.c | 79 ++++++++++++++++++++++++++------------------
1 file changed, 47 insertions(+), 32 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 724e6d7e128f..07de5cc2aa25 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6912,7 +6912,13 @@ static void perf_sample_regs_intr(struct perf_regs
*regs_intr,
*/
static u64 perf_ustack_task_size(struct pt_regs *regs)
{
- unsigned long addr = perf_user_stack_pointer(regs);
+ unsigned long addr;
+
+ /* No regs, no stack pointer, no dump. */
+ if (!regs)
+ return 0;
+
+ addr = perf_user_stack_pointer(regs);
if (!addr || addr >= TASK_SIZE)
return 0;
@@ -6921,42 +6927,35 @@ static u64 perf_ustack_task_size(struct pt_regs *regs)
}
static u16
-perf_sample_ustack_size(u16 stack_size, u16 header_size,
- struct pt_regs *regs)
+perf_sample_dump_size(u16 dump_size, u16 header_size, u64 task_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:
+ * Check if we fit in with the requested dump size into the:
* - TASK_SIZE
* If we don't, we limit the size to the TASK_SIZE.
*
* - remaining sample size
- * If we don't, we customize the stack size to
+ * If we don't, we customize the dump size to
* fit in to the remaining sample size.
*/
- task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
- stack_size = min(stack_size, (u16) task_size);
+ task_size = min((u64) USHRT_MAX, task_size);
+ dump_size = min(dump_size, (u16) task_size);
/* Current header size plus static size and dynamic size. */
header_size += 2 * sizeof(u64);
- /* Do we fit in with the current stack dump size? */
- if ((u16) (header_size + stack_size) < header_size) {
+ /* Do we fit in with the current dump size? */
+ if ((u16) (header_size + dump_size) < header_size) {
/*
* If we overflow the maximum size for the sample,
- * we customize the stack dump size to fit in.
+ * we customize the dump size to fit in.
*/
- stack_size = USHRT_MAX - header_size - sizeof(u64);
- stack_size = round_up(stack_size, sizeof(u64));
+ dump_size = USHRT_MAX - header_size - sizeof(u64);
+ dump_size = round_up(dump_size, sizeof(u64));
}
- return stack_size;
+ return dump_size;
}
static void
@@ -7648,6 +7647,32 @@ static __always_inline u64 __cond_set(u64 flags, u64 s,
u64 d)
return d * !!(flags & s);
}
+static inline u16
+perf_prepare_dump_data(struct perf_sample_data *data,
+ struct perf_event *event,
+ struct pt_regs *regs,
+ u16 dump_size,
+ u64 task_size)
+{
+ u16 header_size = perf_sample_data_size(data, event);
+ u16 size = sizeof(u64);
+
+ dump_size = perf_sample_dump_size(dump_size, header_size,
+ task_size);
+
+ /*
+ * If there is something to dump, add space for the dump
+ * itself and for the field that tells the dynamic size,
+ * which is how many have been actually dumped.
+ */
+ if (dump_size)
+ size += sizeof(u64) + dump_size;
+
+ data->dyn_size += size;
+
+ return dump_size;
+}
+
void perf_prepare_sample(struct perf_sample_data *data,
struct perf_event *event,
struct pt_regs *regs)
@@ -7725,22 +7750,12 @@ void perf_prepare_sample(struct perf_sample_data *data,
* up the rest of the sample size.
*/
u16 stack_size = event->attr.sample_stack_user;
- u16 header_size = perf_sample_data_size(data, event);
- u16 size = sizeof(u64);
-
- stack_size = perf_sample_ustack_size(stack_size, header_size,
- data->regs_user.regs);
+ u64 task_size = perf_ustack_task_size(regs);
- /*
- * If there is something to dump, add space for the dump
- * itself and for the field that tells the dynamic size,
- * which is how many have been actually dumped.
- */
- if (stack_size)
- size += sizeof(u64) + stack_size;
+ stack_size = perf_prepare_dump_data(data, event, regs,
+ stack_size, task_size);
data->stack_user_size = stack_size;
- data->dyn_size += size;
data->sample_flags |= PERF_SAMPLE_STACK_USER;
}
--
2.34.1
