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author | Kim Phillips <kim.phillips@arm.com> | 2018-08-27 12:53:40 -0500 |
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committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2018-08-30 15:51:54 -0300 |
commit | 4e67b2a5df5d3f341776d12ee575e00ca3ef92de (patch) | |
tree | 7abfd25b957743d5639aec34612cd51808fb91b4 /kernel/events | |
parent | fa694160cca6dbba17c57dc7efec5f93feaf8795 (diff) | |
download | lwn-4e67b2a5df5d3f341776d12ee575e00ca3ef92de.tar.gz lwn-4e67b2a5df5d3f341776d12ee575e00ca3ef92de.zip |
perf annotate: Fix parsing aarch64 branch instructions after objdump update
Starting with binutils 2.28, aarch64 objdump adds comments to the
disassembly output to show the alternative names of a condition code
[1].
It is assumed that commas in objdump comments could occur in other
arches now or in the future, so this fix is arch-independent.
The fix could have been done with arm64 specific jump__parse and
jump__scnprintf functions, but the jump__scnprintf instruction would
have to have its comment character be a literal, since the scnprintf
functions cannot receive a struct arch easily.
This inconvenience also applies to the generic jump__scnprintf, which is
why we add a raw_comment pointer to struct ins_operands, so the __parse
function assigns it to be re-used by its corresponding __scnprintf
function.
Example differences in 'perf annotate --stdio2' output on an aarch64
perf.data file:
BEFORE: → b.cs ffff200008133d1c <unwind_frame+0x18c> // b.hs, dffff7ecc47b
AFTER : ↓ b.cs 18c
BEFORE: → b.cc ffff200008d8d9cc <get_alloc_profile+0x31c> // b.lo, b.ul, dffff727295b
AFTER : ↓ b.cc 31c
The branch target labels 18c and 31c also now appear in the output:
BEFORE: add x26, x29, #0x80
AFTER : 18c: add x26, x29, #0x80
BEFORE: add x21, x21, #0x8
AFTER : 31c: add x21, x21, #0x8
The Fixes: tag below is added so stable branches will get the update; it
doesn't necessarily mean that commit was broken at the time, rather it
didn't withstand the aarch64 objdump update.
Tested no difference in output for sample x86_64, power arch perf.data files.
[1] https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commit;h=bb7eff5206e4795ac79c177a80fe9f4630aaf730
Signed-off-by: Kim Phillips <kim.phillips@arm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Taeung Song <treeze.taeung@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Fixes: b13bbeee5ee6 ("perf annotate: Fix branch instruction with multiple operands")
Link: http://lkml.kernel.org/r/20180827125340.a2f7e291901d17cea05daba4@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'kernel/events')
0 files changed, 0 insertions, 0 deletions