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| author | Valentin Schneider <valentin.schneider@arm.com> | 2022-05-05 18:32:07 +0200 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2022-05-16 19:15:18 +0100 |
| commit | c733812dd77350ba0da18cd6e474e5a2e6461b49 (patch) | |
| tree | 5efa5e4924b2d054dfc0a3f927a4deb6388cb02c /arch/arm64/include/asm/pgtable.h | |
| parent | b4d6bb38f9dc7cd8ccb117c247a41ec12578929c (diff) | |
| download | linux-c733812dd77350ba0da18cd6e474e5a2e6461b49.tar.bz2 | |
arm64: mm: Make arch_faults_on_old_pte() check for migratability
arch_faults_on_old_pte() relies on the calling context being
non-preemptible. CONFIG_PREEMPT_RT turns the PTE lock into a sleepable
spinlock, which doesn't disable preemption once acquired, triggering the
warning in arch_faults_on_old_pte().
It does however disable migration, ensuring the task remains on the same
CPU during the entirety of the critical section, making the read of
cpu_has_hw_af() safe and stable.
Make arch_faults_on_old_pte() check cant_migrate() instead of preemptible().
Cc: Valentin Schneider <vschneid@redhat.com>
Suggested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lore.kernel.org/r/20220127192437.1192957-1-valentin.schneider@arm.com
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220505163207.85751-4-bigeasy@linutronix.de
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/pgtable.h')
| -rw-r--r-- | arch/arm64/include/asm/pgtable.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 94e147e5456c..9c0a9bfd6b07 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -1001,7 +1001,8 @@ static inline void update_mmu_cache(struct vm_area_struct *vma, */ static inline bool arch_faults_on_old_pte(void) { - WARN_ON(preemptible()); + /* The register read below requires a stable CPU to make any sense */ + cant_migrate(); return !cpu_has_hw_af(); } |