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authorLinus Torvalds <torvalds@linux-foundation.org>2015-02-16 14:58:12 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-16 14:58:12 -0800
commit37507717de51a8332a34ee07fd88700be88df5bf (patch)
treed6eb5d00a798a4b1ce40c8c4c8ca74b0d22fe1df /arch/x86/kernel/setup.c
parenta68fb48380bb993306dd62a58cbd946b4348222a (diff)
parenta66734297f78707ce39d756b656bfae861d53f62 (diff)
downloadlinux-37507717de51a8332a34ee07fd88700be88df5bf.tar.bz2
Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/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
Diffstat (limited to 'arch/x86/kernel/setup.c')
-rw-r--r--arch/x86/kernel/setup.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 27d200929864..0a2421cca01f 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1179,7 +1179,7 @@ void __init setup_arch(char **cmdline_p)
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;
}