linux-kernel - [PATCH 3/7] perf/x86/intel/pt: Fix pt_topa_entry_for

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Date: Mon, 24 Jun 2024 23:10:57 +0300
From: Adrian Hunter <adrian.hunter@...el.com>
To: Peter Zijlstra <peterz@...radead.org>
Cc: Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	x86@...nel.org,
	H Peter Anvin <hpa@...or.com>,
	Mark Rutland <mark.rutland@....com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Marco Cavenati <cavenati.marco@...il.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Jiri Olsa <jolsa@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Ian Rogers <irogers@...gle.com>,
	Kan Liang <kan.liang@...ux.intel.com>,
	linux-kernel@...r.kernel.org,
	linux-perf-users@...r.kernel.org
Subject: [PATCH 3/7] perf/x86/intel/pt: Fix pt_topa_entry_for_page() address calculation

Currently, perf allocates an array of page pointers which is limited in
size by MAX_PAGE_ORDER. That in turn limits the maximum Intel PT buffer
size to 2GiB. Should that limitation be lifted, the Intel PT driver can
support larger sizes, except for one calculation in
pt_topa_entry_for_page(), which is limited to 32-bits.

Fix pt_topa_entry_for_page() address calculation by adding a cast.

Fixes: 39152ee51b77 ("perf/x86/intel/pt: Get rid of reverse lookup table for ToPA")
Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
---
 arch/x86/events/intel/pt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c
index 047a2cd5b3fe..b4aa8daa4773 100644
--- a/arch/x86/events/intel/pt.c
+++ b/arch/x86/events/intel/pt.c
@@ -990,7 +990,7 @@ pt_topa_entry_for_page(struct pt_buffer *buf, unsigned int pg)
 	 * order allocations, there shouldn't be many of these.
 	 */
 	list_for_each_entry(topa, &buf->tables, list) {
-		if (topa->offset + topa->size > pg << PAGE_SHIFT)
+		if (topa->offset + topa->size > (unsigned long)pg << PAGE_SHIFT)
 			goto found;
 	}
 
-- 
2.34.1