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| author |   Catalin Marinas <catalin.marinas@arm.com> | 2017-07-06 11:46:39 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2017-08-21 11:12:39 +0100 |
| commit | 0966253d7ccddc42a5211b3488bb4f202c04de1b (patch) | |
| tree | b20b966306224972d5e464e41c7d9cd2445fe0db | |
| parent | arm64: Convert pte handling from inline asm to using (cmp)xchg (diff) | |
| download | linux-dev-0966253d7ccddc42a5211b3488bb4f202c04de1b.tar.xz linux-dev-0966253d7ccddc42a5211b3488bb4f202c04de1b.zip | |
kvm: arm64: Convert kvm_set_s2pte_readonly() from inline asm to cmpxchg()
To take advantage of the LSE atomic instructions and also make the code
cleaner, convert the kvm_set_s2pte_readonly() function to use the more
generic cmpxchg().
Cc: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| -rw-r--r-- | arch/arm64/include/asm/kvm_mmu.h | 21 |
1 files changed, 9 insertions, 12 deletions
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index a89cc22abadc..672c8684d5c2 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -175,18 +175,15 @@ static inline pmd_t kvm_s2pmd_mkwrite(pmd_t pmd) static inline void kvm_set_s2pte_readonly(pte_t *pte) { - pteval_t pteval; - unsigned long tmp; - - asm volatile("// kvm_set_s2pte_readonly\n" - " prfm pstl1strm, %2\n" - "1: ldxr %0, %2\n" - " and %0, %0, %3 // clear PTE_S2_RDWR\n" - " orr %0, %0, %4 // set PTE_S2_RDONLY\n" - " stxr %w1, %0, %2\n" - " cbnz %w1, 1b\n" - : "=&r" (pteval), "=&r" (tmp), "+Q" (pte_val(*pte)) - : "L" (~PTE_S2_RDWR), "L" (PTE_S2_RDONLY)); + pteval_t old_pteval, pteval; + + pteval = READ_ONCE(pte_val(*pte)); + do { + old_pteval = pteval; + pteval &= ~PTE_S2_RDWR; + pteval |= PTE_S2_RDONLY; + pteval = cmpxchg_relaxed(&pte_val(*pte), old_pteval, pteval); + } while (pteval != old_pteval); } static inline bool kvm_s2pte_readonly(pte_t *pte) |