Messages in this thread | | | Date | Thu, 10 May 2018 17:19:22 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH RFC 07/19] perf tools: Workaround missing maps for x86_64 KPTI entry trampolines |
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Em Thu, May 10, 2018 at 05:15:42PM -0300, Arnaldo Carvalho de Melo escreveu: > Em Thu, May 10, 2018 at 07:08:37PM +0000, Hunter, Adrian escreveu: > > > -----Original Message----- > > > From: Arnaldo Carvalho de Melo [mailto:acme@kernel.org] > > > Sent: Wednesday, May 9, 2018 8:07 PM > > > To: Hunter, Adrian <adrian.hunter@intel.com> > > > Cc: Thomas Gleixner <tglx@linutronix.de>; Ingo Molnar > > > <mingo@redhat.com>; Peter Zijlstra <peterz@infradead.org>; Andy > > > Lutomirski <luto@kernel.org>; H. Peter Anvin <hpa@zytor.com>; Andi Kleen > > > <ak@linux.intel.com>; Alexander Shishkin > > > <alexander.shishkin@linux.intel.com>; Dave Hansen > > > <dave.hansen@linux.intel.com>; Joerg Roedel <joro@8bytes.org>; Jiri Olsa > > > <jolsa@redhat.com>; linux-kernel@vger.kernel.org; x86@kernel.org > > > Subject: Re: [PATCH RFC 07/19] perf tools: Workaround missing maps for > > > x86_64 KPTI entry trampolines > > > > > > Em Wed, May 09, 2018 at 02:43:36PM +0300, Adrian Hunter escreveu: > > > > On x86_64 the KPTI entry trampolines are not in the kernel map created > > > > by perf tools. That results in the addresses having no symbols and > > > > prevents annotation. It also causes Intel PT to have decoding errors > > > > at the trampoline addresses. Workaround that by creating maps for the > > > trampolines. > > > > At present the kernel does not export information revealing where the > > > > trampolines are. Until that happens, the addresses are hardcoded. > > > > > > > > Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> > > > > --- > > > > tools/perf/util/machine.c | 104 > > > ++++++++++++++++++++++++++++++++++++++++++++++ > > > > tools/perf/util/machine.h | 3 ++ > > > > tools/perf/util/symbol.c | 12 +++--- > > > > 3 files changed, 114 insertions(+), 5 deletions(-) > > > > > > > > diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c > > > > index 22047ff3cf2a..1bf15aa0b099 100644 > > > > --- a/tools/perf/util/machine.c > > > > +++ b/tools/perf/util/machine.c > > > > @@ -851,6 +851,110 @@ static int > > > machine__get_running_kernel_start(struct machine *machine, > > > > return 0; > > > > } > > > > > > > > +struct special_kernal_map { > > > > > > s/kernal/kernel/ > > > > > > And "special"? > > > > I have added comment: > > > > /* Kernel-space maps that are not the main kernel map nor a module map */ > > Perhaps: > > /* Kernel-space maps for symbols that are outside the main kernel map and module maps */ > > struct extra_kernel_map; > > What do you think? > > > And fixed kernal, and changed machine__is() > > Thanks > > > Revised patch set is here: > > > > http://git.infradead.org/users/ahunter/linux-perf.git/shortlog/refs/heads/perf-tools-kpti > > > > which is the perf-tools-kpti branch of: > > > > git://git.infradead.org/users/ahunter/linux-perf.git > > > > Let me know if you want me to post the workaround patches separately, > > otherwise I will wait a bit before sending the patches again. > > I'll see if I went thru all of the patches already...
So I looked at the patches posted and one comment is about the terse commit logs for some of the kcore_copy patches, for instance:
-------------------- In preparation to add more program headers, get rid of kernel_map and modules_map. --------------------
Can't this be made a bit more verbose? Lemme re-read the patch...
- Arnaldo
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