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authorCatalin Marinas <catalin.marinas@arm.com>2017-07-06 11:46:39 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2017-08-21 11:12:39 +0100
commit0966253d7ccddc42a5211b3488bb4f202c04de1b (patch)
treeb20b966306224972d5e464e41c7d9cd2445fe0db /arch/arm64/include
parentarm64: Convert pte handling from inline asm to using (cmp)xchg (diff)
downloadlinux-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>
Diffstat (limited to 'arch/arm64/include')
-rw-r--r--arch/arm64/include/asm/kvm_mmu.h21
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)