Commit-ID:  d3b70220292c40d3b499797fd2f33f608fc35edb
Gitweb:     http://git.kernel.org/tip/d3b70220292c40d3b499797fd2f33f608fc35edb
Author:     Adrian Hunter <[email protected]>
AuthorDate: Wed, 29 Jan 2014 16:14:44 +0200
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Fri, 31 Jan 2014 17:21:54 -0300

perf buildid-cache: Check relocation when checking for existing kcore

perf buildid-cache does not make another copy of kcore if the buildid
and modules match an existing copy.

That does not take into account the possibility that the kernel has been
relocated.

Extend the check to check if the reference relocation symbol matches
too, otherwise do make a copy.

Signed-off-by: Adrian Hunter <[email protected]>
Tested-by: Jiri Olsa <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: 
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
 tools/perf/builtin-buildid-cache.c | 33 +++++++++++++++++++++++++++++----
 1 file changed, 29 insertions(+), 4 deletions(-)

diff --git a/tools/perf/builtin-buildid-cache.c 
b/tools/perf/builtin-buildid-cache.c
index cfede86..b22dbb1 100644
--- a/tools/perf/builtin-buildid-cache.c
+++ b/tools/perf/builtin-buildid-cache.c
@@ -63,11 +63,35 @@ static int build_id_cache__kcore_dir(char *dir, size_t sz)
        return 0;
 }
 
+static bool same_kallsyms_reloc(const char *from_dir, char *to_dir)
+{
+       char from[PATH_MAX];
+       char to[PATH_MAX];
+       const char *name;
+       u64 addr1 = 0, addr2 = 0;
+       int i;
+
+       scnprintf(from, sizeof(from), "%s/kallsyms", from_dir);
+       scnprintf(to, sizeof(to), "%s/kallsyms", to_dir);
+
+       for (i = 0; (name = ref_reloc_sym_names[i]) != NULL; i++) {
+               addr1 = kallsyms__get_function_start(from, name);
+               if (addr1)
+                       break;
+       }
+
+       if (name)
+               addr2 = kallsyms__get_function_start(to, name);
+
+       return addr1 == addr2;
+}
+
 static int build_id_cache__kcore_existing(const char *from_dir, char *to_dir,
                                          size_t to_dir_sz)
 {
        char from[PATH_MAX];
        char to[PATH_MAX];
+       char to_subdir[PATH_MAX];
        struct dirent *dent;
        int ret = -1;
        DIR *d;
@@ -86,10 +110,11 @@ static int build_id_cache__kcore_existing(const char 
*from_dir, char *to_dir,
                        continue;
                scnprintf(to, sizeof(to), "%s/%s/modules", to_dir,
                          dent->d_name);
-               if (!compare_proc_modules(from, to)) {
-                       scnprintf(to, sizeof(to), "%s/%s", to_dir,
-                                 dent->d_name);
-                       strlcpy(to_dir, to, to_dir_sz);
+               scnprintf(to_subdir, sizeof(to_subdir), "%s/%s",
+                         to_dir, dent->d_name);
+               if (!compare_proc_modules(from, to) &&
+                   same_kallsyms_reloc(from_dir, to_subdir)) {
+                       strlcpy(to_dir, to_subdir, to_dir_sz);
                        ret = 0;
                        break;
                }
--
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