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