linux-kernel - [PATCH] powerpc, perf: Clear out branch entries to avoid any previous stale values

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Mon,  6 May 2013 13:34:40 +0530
From:	Anshuman Khandual <khandual@...ux.vnet.ibm.com>
To:	linuxppc-dev@...abs.org, linux-kernel@...r.kernel.org
Cc:	michael@...erman.id.au, mikey@...ling.org, benh@...nel.crashing.org
Subject: [PATCH] powerpc, perf: Clear out branch entries to avoid any previous stale values

The 'to' field inside branch entries might contain stale values from previous
PMU interrupt instances which had indirect branches. So clear all the values
before reading a fresh set of BHRB entries after a PMU interrupt.

Signed-off-by: Anshuman Khandual <khandual@...ux.vnet.ibm.com>
---
 arch/powerpc/perf/core-book3s.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index c627843..09db68d 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -1590,6 +1590,8 @@ static void record_and_restart(struct perf_event *event, unsigned long val,
 		if (event->attr.sample_type & PERF_SAMPLE_BRANCH_STACK) {
 			struct cpu_hw_events *cpuhw;
 			cpuhw = &__get_cpu_var(cpu_hw_events);
+			memset(cpuhw->bhrb_entries, 0,
+				sizeof(struct perf_branch_entry) * BHRB_MAX_ENTRIES);
 			power_pmu_bhrb_read(cpuhw);
 			data.br_stack = &cpuhw->bhrb_stack;
 		}
-- 
1.7.11.7

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/