This is a note to let you know that I've just added the patch titled
perf/x86/intel/pt: Use pointer arithmetics instead in ToPA entry calculation
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-x86-intel-pt-use-pointer-arithmetics-instead-in.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d2bb4df617e24af891b904a6cd9ac8b386bb6e45
Author: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Date: Wed Aug 21 15:47:24 2019 +0300
perf/x86/intel/pt: Use pointer arithmetics instead in ToPA entry calculation
[ 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>
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);
