aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorWill Deacon2020-09-30 13:20:40 +0100
committerWill Deacon2020-10-01 09:45:32 +0100
commit6a1bdb173f9967b2329aab0f25bcba963f54e06b (patch)
tree5f504bd8dd7dc5c1b67bedf76ca5726c503979fa
parente676594115f0bcc12d4791f9ee919e20d8d750ee (diff)
arm64: mm: Make flush_tlb_fix_spurious_fault() a no-op
Our use of broadcast TLB maintenance means that spurious page-faults that have been handled already by another CPU do not require additional TLB maintenance. Make flush_tlb_fix_spurious_fault() a no-op and rely on the existing TLB invalidation instead. Add an explicit flush_tlb_page() when making a page dirty, as the TLB is permitted to cache the old read-only entry. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20200728092220.GA21800@willie-the-truck Signed-off-by: Will Deacon <will@kernel.org>
-rw-r--r--arch/arm64/include/asm/pgtable.h8
-rw-r--r--arch/arm64/mm/fault.c4
2 files changed, 11 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index bc68da9f5706..02ad3105c14c 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -51,6 +51,14 @@ extern void __pgd_error(const char *file, int line, unsigned long val);
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
/*
+ * Outside of a few very special situations (e.g. hibernation), we always
+ * use broadcast TLB invalidation instructions, therefore a spurious page
+ * fault on one CPU which has been handled concurrently by another CPU
+ * does not need to perform additional invalidation.
+ */
+#define flush_tlb_fix_spurious_fault(vma, address) do { } while (0)
+
+/*
* ZERO_PAGE is a global shared page that is always zero: used
* for zero-mapped memory areas etc..
*/
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index f07333e86c2f..a696a7921da4 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -218,7 +218,9 @@ int ptep_set_access_flags(struct vm_area_struct *vma,
pteval = cmpxchg_relaxed(&pte_val(*ptep), old_pteval, pteval);
} while (pteval != old_pteval);
- flush_tlb_fix_spurious_fault(vma, address);
+ /* Invalidate a stale read-only entry */
+ if (dirty)
+ flush_tlb_page(vma, address);
return 1;
}