4.19-stable review patch. If anyone has any objections, please let me know.
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From: Alexander Shishkin alexander.shishkin@linux.intel.com
[ 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@linux.intel.com Cc: Arnaldo Carvalho de Melo acme@redhat.com Cc: Jiri Olsa jolsa@redhat.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra a.p.zijlstra@chello.nl Cc: Peter Zijlstra peterz@infradead.org Cc: Stephane Eranian eranian@google.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Vince Weaver vincent.weaver@maine.edu Link: http://lkml.kernel.org/r/20190821124727.73310-4-alexander.shishkin@linux.int... Signed-off-by: Ingo Molnar mingo@kernel.org Stable-dep-of: ad97196379d0 ("perf/x86/intel/pt: Fix a topa_entry base address calculation") Signed-off-by: Sasha Levin sashal@kernel.org --- 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);