[PATCH] perf trace: Add mmap alias for s390

[Jiri Olsa]

The s390 architecture maps sys_mmap (nr 90) into sys_old_mmap.
For this reason perf trace can't find the proper syscall event
to get args format from and displays it wrong as 'continued'.

To fix that fill "alias" field with "old_mmap" for trace's mmap
record to get the correct translation.

Before:
     0.042 ( 0.011 ms): vest/43052 fstat(statbuf: 0x3ffff89fd90                ) = 0
     0.042 ( 0.028 ms): vest/43052  ... [continued]: mmap()) = 0x3fffd6e2000
     0.072 ( 0.025 ms): vest/43052 read(buf: 0x3fffd6e2000, count: 4096        ) = 6

After:
     0.045 ( 0.011 ms): fstat(statbuf: 0x3ffff8a0930                           ) = 0
     0.057 ( 0.018 ms): mmap(arg: 0x3ffff8a0858                                ) = 0x3fffd14a000
     0.076 ( 0.025 ms): read(buf: 0x3fffd14a000, count: 4096                   ) = 6

Link: http://lkml.kernel.org/n/tip-3jrfsbpclxr1ftke2t9rpvy6@xxxxxxxxxxxxxx
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
 tools/perf/builtin-trace.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index d014350adc52..4b2a5d298197 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -681,6 +681,10 @@ static struct syscall_fmt {
 	{ .name	    = "mlockall",   .errmsg = true,
 	  .arg_scnprintf = { [0] = SCA_HEX, /* addr */ }, },
 	{ .name	    = "mmap",	    .hexret = true,
+/* The standard mmap maps to old_mmap on s390x */
+#if defined(__s390x__)
+	.alias = "old_mmap",
+#endif
 	  .arg_scnprintf = { [0] = SCA_HEX,	  /* addr */
 			     [2] = SCA_MMAP_PROT, /* prot */
 			     [3] = SCA_MMAP_FLAGS, /* flags */ }, },
-- 
2.9.4