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SubjectRe: [PATCH V4 3/3] x86: Add entry trampolines to kcore
Em Wed, Jun 06, 2018 at 03:16:31PM +0200, Peter Zijlstra escreveu:
> On Wed, Jun 06, 2018 at 03:54:11PM +0300, Adrian Hunter wrote:
> > Without program headers for PTI entry trampoline pages, the trampoline
> > virtual addresses do not map to anything.
> >
>
> >
> > In addition, entry trampolines all map to the same page. Represent that by
> > giving the corresponding program headers in kcore the same offset.
> >
> > This has the benefit that, when perf tools uses /proc/kcore as a source for
> > kernel object code, samples from different CPU trampolines are aggregated
> > together. Note, such aggregation is normal for profiling i.e. people want
> > to profile the object code, not every different virtual address the object
> > code might be mapped to (across different processes for example).
> >
> > Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> > Acked-by: Andi Kleen <ak@linux.intel.com>
> > ---
> > arch/x86/mm/cpu_entry_area.c | 10 ++++++++++
> > fs/proc/kcore.c | 7 +++++--
> > include/linux/kcore.h | 13 +++++++++++++
> > 3 files changed, 28 insertions(+), 2 deletions(-)
>
> This also adds the KCORE_REMAP functionality, but isn't mentioned at all
> in the Changelog.
>
> Still, looks OK I suppose,

I can add a note about that,

> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Thanks, giving it some more hours and will apply and try to test it.

- Arnaldo

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