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| author | Jan Kiszka <jan.kiszka@siemens.com> | 2019-06-18 09:32:11 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-07-24 14:43:37 +0200 |
| commit | 21e450d21ccad4cb7c7984c29ff145012b47736d (patch) | |
| tree | 17a6ad3e3620cedd781fa9096abaa4d3b14d0a30 /arch/x86/include/asm/mmu_context.h | |
| parent | Linus 5.3-rc1 (diff) | |
| download | linux-21e450d21ccad4cb7c7984c29ff145012b47736d.tar.xz linux-21e450d21ccad4cb7c7984c29ff145012b47736d.zip | |
x86/mm: Avoid redundant interrupt disable in load_mm_cr4()
load_mm_cr4() is always called with interrupts disabled from:
- switch_mm_irqs_off()
- refresh_pce(), which is a on_each_cpu() callback
Thus, disabling interrupts in cr4_set/clear_bits() is redundant.
Implement cr4_set/clear_bits_irqsoff() helpers, rename load_mm_cr4() to
load_mm_cr4_irqsoff() and use the new helpers. The new helpers do not need
a lockdep assert as __cr4_set() has one already.
The renaming in combination with the checks in __cr4_set() ensure that any
changes in the boundary conditions at the call sites will be detected.
[ tglx: Massaged change log ]
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/0fbbcb64-5f26-4ffb-1bb9-4f5f48426893@siemens.com
Diffstat (limited to 'arch/x86/include/asm/mmu_context.h')
| -rw-r--r-- | arch/x86/include/asm/mmu_context.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index 9024236693d2..16ae821483c8 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -28,16 +28,16 @@ static inline void paravirt_activate_mm(struct mm_struct *prev, DECLARE_STATIC_KEY_FALSE(rdpmc_always_available_key); -static inline void load_mm_cr4(struct mm_struct *mm) +static inline void load_mm_cr4_irqsoff(struct mm_struct *mm) { if (static_branch_unlikely(&rdpmc_always_available_key) || atomic_read(&mm->context.perf_rdpmc_allowed)) - cr4_set_bits(X86_CR4_PCE); + cr4_set_bits_irqsoff(X86_CR4_PCE); else - cr4_clear_bits(X86_CR4_PCE); + cr4_clear_bits_irqsoff(X86_CR4_PCE); } #else -static inline void load_mm_cr4(struct mm_struct *mm) {} +static inline void load_mm_cr4_irqsoff(struct mm_struct *mm) {} #endif #ifdef CONFIG_MODIFY_LDT_SYSCALL |