From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Mon, 16 Feb 2015 22:58:12 +0000 (-0800)
Subject: Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git... 
X-Git-Tag: v4.0-rc1~77
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=37507717de51a8332a34ee07fd88700be88df5bf;p=platform%2Fkernel%2Flinux-exynos.git

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

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
---

37507717de51a8332a34ee07fd88700be88df5bf
diff --cc arch/x86/kernel/setup.c
index 27d2009,04e6c62..0a2421c
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@@ -1175,11 -1176,9 +1175,11 @@@ void __init setup_arch(char **cmdline_p
  
  	x86_init.paging.pagetable_init();
  
 +	kasan_init();
 +
  	if (boot_cpu_data.cpuid_level >= 0) {
  		/* A CPU has %cr4 if and only if it has CPUID */
- 		mmu_cr4_features = read_cr4();
+ 		mmu_cr4_features = __read_cr4();
  		if (trampoline_cr4_features)
  			*trampoline_cr4_features = mmu_cr4_features;
  	}