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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-16 14:58:12 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-16 14:58:12 -0800 |
| commit | 37507717de51a8332a34ee07fd88700be88df5bf (patch) | |
| tree | d6eb5d00a798a4b1ce40c8c4c8ca74b0d22fe1df /arch/x86/power/cpu.c | |
| parent | a68fb48380bb993306dd62a58cbd946b4348222a (diff) | |
| parent | a66734297f78707ce39d756b656bfae861d53f62 (diff) | |
| download | linux-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/power/cpu.c')
| -rw-r--r-- | arch/x86/power/cpu.c | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c index 6ec7910f59bf..3e32ed5648a0 100644 --- a/arch/x86/power/cpu.c +++ b/arch/x86/power/cpu.c @@ -105,11 +105,8 @@ static void __save_processor_state(struct saved_context *ctxt) ctxt->cr0 = read_cr0(); ctxt->cr2 = read_cr2(); ctxt->cr3 = read_cr3(); -#ifdef CONFIG_X86_32 - ctxt->cr4 = read_cr4_safe(); -#else -/* CONFIG_X86_64 */ - ctxt->cr4 = read_cr4(); + ctxt->cr4 = __read_cr4_safe(); +#ifdef CONFIG_X86_64 ctxt->cr8 = read_cr8(); #endif ctxt->misc_enable_saved = !rdmsrl_safe(MSR_IA32_MISC_ENABLE, @@ -175,12 +172,12 @@ static void notrace __restore_processor_state(struct saved_context *ctxt) /* cr4 was introduced in the Pentium CPU */ #ifdef CONFIG_X86_32 if (ctxt->cr4) - write_cr4(ctxt->cr4); + __write_cr4(ctxt->cr4); #else /* CONFIG X86_64 */ wrmsrl(MSR_EFER, ctxt->efer); write_cr8(ctxt->cr8); - write_cr4(ctxt->cr4); + __write_cr4(ctxt->cr4); #endif write_cr3(ctxt->cr3); write_cr2(ctxt->cr2); |