On 06/06/18 16:19, Arnaldo Carvalho de Melo wrote: > 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 <[email protected]> >>> Acked-by: Andi Kleen <[email protected]> >>> --- >>> 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) <[email protected]> > > Thanks, giving it some more hours and will apply and try to test it.
Any update on this?
