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Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull x86 perf updates from Ingo Molnar:
 "This series tightens up RDPMC permissions: currently even highly
  sandboxed x86 execution environments (such as seccomp) have permission
  to execute RDPMC, which may leak various perf events / PMU state such
  as timing information and other CPU execution details.

  This 'all is allowed' RDPMC mode is still preserved as the
  (non-default) /sys/devices/cpu/rdpmc=2 setting.  The new default is
  that RDPMC access is only allowed if a perf event is mmap-ed (which is
  needed to correctly interpret RDPMC counter values in any case).

  As a side effect of these changes CR4 handling is cleaned up in the
  x86 code and a shadow copy of the CR4 value is added.

  The extra CR4 manipulation adds ~ <50ns to the context switch cost
  between rdpmc-capable and rdpmc-non-capable mms"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86: Add /sys/devices/cpu/rdpmc=2 to allow rdpmc for all tasks
  perf/x86: Only allow rdpmc if a perf_event is mapped
  perf: Pass the event to arch_perf_update_userpage()
  perf: Add pmu callbacks to track event mapping and unmapping
  x86: Add a comment clarifying LDT context switching
  x86: Store a per-cpu shadow copy of CR4
  x86: Clean up cr4 manipulation
This commit is contained in:
Linus Torvalds
2015-02-16 14:58:12 -08:00
parent a68fb48380 a66734297f
commit 37507717de
35 changed files with 253 additions and 120 deletions
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4
arch/x86/xen/enlighten.c
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@@ -1494,10 +1494,10 @@ static void xen_pvh_set_cr_flags(int cpu)
* set them here. For all, OSFXSR OSXMMEXCPT are set in fpu_init.
*/
if (cpu_has_pse)
set_in_cr4(X86_CR4_PSE);
cr4_set_bits_and_update_boot(X86_CR4_PSE);
if (cpu_has_pge)
set_in_cr4(X86_CR4_PGE);
cr4_set_bits_and_update_boot(X86_CR4_PGE);
}
/*