Re: [PATCH] tools/perf: Fix the mask in regs_dump__printf

On Fri, Jun 17, 2016 at 02:43:31PM +0530, Madhavan Srinivasan wrote:

SNIP

 
                if (data->user_regs.abi) {
-                       u64 mask = evsel->attr.sample_regs_user;
+                       u.val64 = evsel->attr.sample_regs_user;
 
-                       sz = hweight_long(mask) * sizeof(u64);
+                       if (sizeof(u64) > sizeof(unsigned long)) {
+                               u64 mask = u.val64;
+                               u.val32[1] = mask >> 32;
+                               u.val32[0] = mask & ULONG_MAX;
+                       }
+
+                       sz = hweight_long(u.val64) * sizeof(u64);
                        OVERFLOW_CHECK(array, sz, max_size);
-                       data->user_regs.mask = mask;
+                       data->user_regs.mask = u.val64;
                        data->user_regs.regs = (u64 *)array;

Issue I see is when printing the mask value in a 32bit perf
on a 64bit kernel (big endian).

442044948492 0xdc0 [0x188]: PERF_RECORD_SAMPLE(IP, 0x1): 7299/7299:
0xc000000000059200 period: 12599 addr: 0
... intr regs: mask 0xffffffff000007ff ABI 32-bit
                            ^^^ shld have been 0x7ffffffffff

I agree it is better to fix this when reading, but
we need to swap again when printing?

hum, sample data should be swap at this point already..
see perf_session__process_event

jirka