commit bb19af816025 ("powerpc/perf: Prevent kernel address leak to
userspace via BHRB buffer") added a check in bhrb_read() to filter
the kernel address from BHRB buffer. This patch modified it to avoid
that check for PowerISA v3.1 based processors, since PowerISA v3.1
allows only MSR[PR]=1 address to be written to BHRB buffer.
Signed-off-by: Athira Rajeev <atraj...@linux.vnet.ibm.com>
---
arch/powerpc/perf/core-book3s.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 0ffb757d..bd125fe 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -469,8 +469,11 @@ static void power_pmu_bhrb_read(struct perf_event *event,
struct cpu_hw_events *
* addresses at this point. Check the privileges before
* exporting it to userspace (avoid exposure of regions
* where we could have speculative execution)
+ * Incase of ISA v3.1, BHRB will capture only user-space
+ * addresses, hence include a check before filtering
code
*/
- if (is_kernel_addr(addr) &&
perf_allow_kernel(&event->attr) != 0)
+ if (!(ppmu->flags & PPMU_ARCH_310S) &&
+ is_kernel_addr(addr) &&
perf_allow_kernel(&event->attr) != 0)
continue;
/* Branches are read most recent first (ie. mfbhrb 0 is
--
1.8.3.1
