[tip:perf/core] perf tools: Fix kernel_start for PTI on x86

[tip-bot for Adrian Hunter]

Commit-ID:  19422a9f2a3be7f3a046285ffae4cbb571aa853a
Gitweb:     https://git.kernel.org/tip/19422a9f2a3be7f3a046285ffae4cbb571aa853a
Author:     Adrian Hunter <adrian.hunter@xxxxxxxxx>
AuthorDate: Thu, 17 May 2018 12:21:54 +0300
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Sat, 19 May 2018 06:42:51 -0300

perf tools: Fix kernel_start for PTI on x86

Opickn 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@xxxxxxxxx>
Tested-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: x86@xxxxxxxxxx
Link: http://lkml.kernel.org/r/1526548928-20790-7-git-send-email-adrian.hunter@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 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 107bae7676b1..e011a7160380 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2321,7 +2321,12 @@ 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;