[PATCH 4.14 44/62] perf tools: Fix kernel_start for PTI on x86

Greg Kroah-Hartman
2018-11-26T11:00:31Z

commit 19422a9f2a3be7f3a046285ffae4cbb571aa853a upstream.

On x86_64, PTI entry trampolines are less than the start of kernel text,
but still above 2^63. So leave kernel_start = 1ULL << 63 for x86_64.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/1526548928-20790-7-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/perf/util/machine.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 2af879693fbe..af18c3d55642 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2263,7 +2263,12 @@ int machine__get_kernel_start(struct machine *machine)
machine->kernel_start = 1ULL << 63;
if (map) {
err = map__load(map);
- if (!err)
+ /*
+ * On x86_64, PTI entry trampolines are less than the
+ * start of kernel text, but still above 2^63. So leave
+ * kernel_start = 1ULL << 63 for x86_64.
+ */
+ if (!err && !machine__is(machine, "x86_64"))
machine->kernel_start = map->start;
}
return err;
--
2.17.1