4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> [ Upstream commit 539f7c26b41d4ed7d88dd9756de3966ae7ca07b4 ] Currently, pt_buffer_reset_offsets() calculates the current ToPA entry by casting pointers to addresses and performing ungainly subtractions and divisions instead of a simpler pointer arithmetic, which would be perfectly applicable in that case. Fix that. Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Cc: Jiri Olsa <jolsa@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Stephane Eranian <eranian@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Vince Weaver <vincent.weaver@xxxxxxxxx> Link: http://lkml.kernel.org/r/20190821124727.73310-4-alexander.shishkin@xxxxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Stable-dep-of: ad97196379d0 ("perf/x86/intel/pt: Fix a topa_entry base address calculation") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- arch/x86/events/intel/pt.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c index b8a2408383d0c..5dff4548b0875 100644 --- a/arch/x86/events/intel/pt.c +++ b/arch/x86/events/intel/pt.c @@ -1031,8 +1031,7 @@ static void pt_buffer_reset_offsets(struct pt_buffer *buf, unsigned long head) pg = pt_topa_next_entry(buf, pg); buf->cur = (struct topa *)((unsigned long)buf->topa_index[pg] & PAGE_MASK); - buf->cur_idx = ((unsigned long)buf->topa_index[pg] - - (unsigned long)buf->cur) / sizeof(struct topa_entry); + buf->cur_idx = buf->topa_index[pg] - TOPA_ENTRY(buf->cur, 0); buf->output_off = head & (pt_buffer_region_size(buf) - 1); local64_set(&buf->head, head); -- 2.43.0
