kernel/linux.git - Linux kernel stable tree (mirror)

Age	Commit message (Collapse)	Author	Files	Lines
2022-04-09	perf unwind: Don't show unwind error messages when augmenting frame pointer ↵	James Clark	1	-1/+1
	stack Commit Fixes: b9f6fbb3b2c29736 ("perf arm64: Inject missing frames when using 'perf record --call-graph=fp'") intended to add a 'best effort' DWARF unwind that improved the frame pointer stack in most scenarios. It's expected that the unwind will fail sometimes, but this shouldn't be reported as an error. It only works when the return address can be determined from the contents of the link register alone. Fix the error shown when the unwinder requires extra registers by adding a new flag that suppresses error messages. This flag is not set in the normal --call-graph=dwarf unwind mode so that behavior is not changed. Fixes: b9f6fbb3b2c29736 ("perf arm64: Inject missing frames when using 'perf record --call-graph=fp'") Reported-by: John Garry <john.garry@huawei.com> Signed-off-by: James Clark <james.clark@arm.com> Tested-by: John Garry <john.garry@huawei.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexandre Truong <alexandre.truong@arm.com> Cc: German Gomez <german.gomez@arm.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Link: https://lore.kernel.org/r/20220406145651.1392529-1-james.clark@arm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-01-14	perf arm: Fix off-by-one directory path	Ian Rogers	1	-1/+1
	Relative path include works in the regular build due to -I paths but may fail in other situations. Fixes: 83869019c74cc2d0 ("perf arch: Support register names from all archs") Reviewed-by: German Gomez <german.gomez@arm.com> Signed-off-by: Ian Rogers <irogers@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexandre Truong <alexandre.truong@arm.com> Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Clark <james.clark@arm.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> Link: https://lore.kernel.org/r/20220114064822.1806019-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2021-12-22	perf arm64: Inject missing frames when using 'perf record --call-graph=fp'	Alexandre Truong	1	-0/+63
	When unwinding using frame pointers on ARM64, the return address of the current function may not have been pushed into the stack when a function was interrupted, which makes perf show an incorrect call graph to the user. Consider the following example program: void leaf() { /* long computation / } void parent() { // (1) leaf(); // (2) } ... could be compiled into (using gcc -fno-inline -fno-omit-frame-pointer): leaf: / long computation */ nop ret parent: // (1) stp x29, x30, [sp, -16]! mov x29, sp bl parent nop ldp x29, x30, [sp], 16 // (2) ret If the program is interrupted at (1), (2), or any point in "leaf:", the call graph will skip the callers of the current function. We can unwind using the dwarf info and check if the return addr is the same as the LR register, and inject the missing frame into the call graph. Before this patch, the above example shows the following call-graph when recording using "--call-graph fp" mode in ARM64: # Children Self Command Shared Object Symbol # ........ ........ ........ ................ ...................... # 99.86% 99.86% program3 program3 [.] leaf \| ---_start __libc_start_main main leaf As can be seen, the "parent" function is missing. This is specially problematic in "leaf" because for leaf functions the compiler may always omit pushing the return addr into the stack. After this patch, it shows the correct graph: # Children Self Command Shared Object Symbol # ........ ........ ........ ................ ...................... # 99.86% 99.86% program3 program3 [.] leaf \| ---_start __libc_start_main main parent leaf Reviewed-by: James Clark <james.clark@arm.com> Signed-off-by: Alexandre Truong <alexandre.truong@arm.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: John Garry <john.garry@huawei.com> Cc: Leo Yan <leo.yan@linaro.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Will Deacon <will@kernel.org> Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20211217154521.80603-7-german.gomez@arm.com Signed-off-by: German Gomez <german.gomez@arm.com> [ Rename machine__normalize_is() to machine__normalized_is(), as suggested by James Clark ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>