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authorArnaldo Carvalho de Melo <acme@redhat.com>2018-12-18 11:05:56 -0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2018-12-18 16:15:19 -0300
commitfb7068e73d2c24ba381938004ed0f285341ef1ba (patch)
tree7460155deb9ee232ea42806c87f926faef82fa0a /mm/vmacache.c
parent9614b8d697350d529743702f095b3db3f6d5a889 (diff)
perf trace beauty: Beautify arch_prctl()'s arguments
This actually so far, AFAIK is available only in x86, so the code was put in place with x86 prefixes, in arches where it is not available it will just not be called, so no further mechanisms are needed at this time. Later, when other arches wire this up, we'll just look at the uname (live sessions) or perf_env data in the perf.data header to auto-wire the right beautifier. With this the output is the same as produced by 'strace' when used with the following ~/.perfconfig: # cat ~/.perfconfig [llvm] dump-obj = true [trace] add_events = /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o show_zeros = yes show_duration = no no_inherit = yes show_timestamp = no show_arg_names = no args_alignment = -40 show_prefix = yes # And, on fedora 29, since the string tables are generated from the kernel sources, we don't know about 0x3001, just like strace: --- /tmp/strace 2018-12-17 11:22:08.707586721 -0300 +++ /tmp/trace 2018-12-18 11:11:32.037512729 -0300 @@ -1,49 +1,49 @@ -arch_prctl(0x3001 /* ARCH_??? */, 0x7ffc8a92dc80) = -1 EINVAL (Invalid argument) +arch_prctl(0x3001 /* ARCH_??? */, 0x7ffe4eb93ae0) = -1 EINVAL (Invalid argument) -arch_prctl(ARCH_SET_FS, 0x7faf6700f540) = 0 +arch_prctl(ARCH_SET_FS, 0x7fb507364540) = 0 And that seems to be related to the CET/Shadow Stack feature, that userland in Fedora 29 (glibc 2.28) are querying the kernel about, that 0x3001 seems to be ARCH_CET_STATUS, I'll check the situation and test with a fedora 29 kernel to see if the other codes are used. A diff that ignores the different pointers for different runs needs to be put in place in the upcoming regression tests comparing 'perf trace's output to strace's. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: https://lkml.kernel.org/n/tip-73a9prs8ktkrt97trtdmdjs8@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'mm/vmacache.c')
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