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authorKim Phillips <kim.phillips@arm.com>2018-08-27 12:53:40 -0500
committerArnaldo Carvalho de Melo <acme@redhat.com>2018-08-30 15:51:54 -0300
commit4e67b2a5df5d3f341776d12ee575e00ca3ef92de (patch)
tree7abfd25b957743d5639aec34612cd51808fb91b4 /kernel/events
parentfa694160cca6dbba17c57dc7efec5f93feaf8795 (diff)
downloadlwn-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>
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