linux_old1/tools
Sukadev Bhattiprolu 8c5073db0e powerpc/perf: Define big-endian version of perf_mem_data_src
perf_mem_data_src is a union that is initialized in the kernel via the ->val
field and accessed by userspace via the mem_xxx bitfields. For this to work
correctly on big endian platforms, we need a big-endian definition for the
bitfields.

Currently on a big endian system, if a user requests PERF_SAMPLE_DATA_SRC (perf
report -d), they will get the default value from perf_sample_data_init(), which
is PERF_MEM_NA. The value for PERF_MEM_NA is constructed using shifts:

  /* TLB access */
  #define PERF_MEM_TLB_NA		0x01 /* not available */
  ...
  #define PERF_MEM_TLB_SHIFT	26

  #define PERF_MEM_S(a, s) \
	(((__u64)PERF_MEM_##a##_##s) << PERF_MEM_##a##_SHIFT)

  #define PERF_MEM_NA (PERF_MEM_S(OP, NA)   |\
		    PERF_MEM_S(LVL, NA)   |\
		    PERF_MEM_S(SNOOP, NA) |\
		    PERF_MEM_S(LOCK, NA)  |\
		    PERF_MEM_S(TLB, NA))

Which works out as:

  ((0x01 << 0) | (0x01 << 5) | (0x01 << 19) | (0x01 << 24) | (0x01 << 26))

Which means the PERF_MEM_NA value comes out of the kernel as 0x5080021
in CPU endian.

But then in the perf tool, the code uses the bitfields to inspect the value, and
currently the bitfields are defined using little endian ordering.

So eg. in perf_mem__tlb_scnprintf() we see:
  data_src->val = 0x5080021
             op = 0x0
            lvl = 0x0
          snoop = 0x0
           lock = 0x0
           dtlb = 0x0
           rsvd = 0x5080021

Because of the way the perf tool code is written this is still displayed to the
user as "N/A", so there is no bug visible at the UI level.

Currently there are no big endian architectures which export a meaningful
value (ie. other than PERF_MEM_NA), so the extent of the bug on big endian
platforms is that the PERF_MEM_NA value is exported incorrectly as described
above. Subsequent patches will add support on big endian powerpc for populating
the data source value.

This patch does a minimal fix of adding big endian definition of the bitfields
to match the values that are already exported by the kernel on big endian. And
it makes no change on little endian.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-04-19 20:00:21 +10:00
..
accounting tools: move accounting tool from Documentation 2016-09-23 13:07:15 -06:00
arch Merge branch 'x86-cpufeature-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-02-20 14:37:08 -08:00
build perf build: Add special fixdep cleaning rule 2017-02-17 16:04:38 -03:00
cgroup
firewire
gpio gpio-hammer: fix make consumer_label suitable to work on gpio-nails 2017-01-26 16:29:09 +01:00
hv Char/Misc driver patches for 4.10-rc1 2016-12-13 12:11:01 -08:00
iio iio: Add channel for Gravity 2017-01-05 13:02:25 +00:00
include powerpc/perf: Define big-endian version of perf_mem_data_src 2017-04-19 20:00:21 +10:00
kvm/kvm_stat
laptop tools: move laptops dslm tool from Documentation 2016-09-23 13:07:21 -06:00
leds tools/leds: Add led_hw_brightness_mon program 2017-02-14 22:20:23 +01:00
lguest scripts/spelling.txt: add "overide" pattern and fix typo instances 2017-03-09 17:01:09 -08:00
lib scripts/spelling.txt: add "overide" pattern and fix typo instances 2017-03-09 17:01:09 -08:00
net
nfsd
objtool objtool: Fix another GCC jump table detection issue 2017-03-07 08:42:55 +01:00
pcmcia tools: move pcmcia crc32hash tool from Documentation 2016-09-23 13:07:27 -06:00
perf Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-17 13:59:52 -07:00
power Power management turbostat utility updates for v4.11-rc1 2017-03-02 17:41:27 -08:00
scripts tools: Suppress request for warning options not existent in clang 2017-02-14 10:34:35 -03:00
spi spi: spidev_test: Fix input file check when transferring file 2016-11-04 09:56:09 -06:00
testing selftests/powerpc: Add cache_shape sniff test 2017-03-20 19:02:49 +11:00
thermal/tmon
time
usb USB: changes for v4.11 2017-01-26 15:36:28 +01:00
virtio tools/virtio/ringtest: tweaks for s390 2017-01-19 23:46:32 +02:00
vm tools/vm: add missing Makefile rules 2017-02-22 16:41:26 -08:00
Makefile tools/leds: Add uledmon program for monitoring userspace LEDs 2016-11-22 12:07:02 +01:00