In the case of a spurious fault (which can happen due to a race with
another thread that changes the page table), the default Linux mm code
calls flush_tlb_page for that address. This is not required because
the pte will be re-fetched. Hash does not wire this up to a hardware
TLB flush for this reason. This patch avoids the flush for radix.
>From Power ISA v3.0B, p.1090:
Setting a Reference or Change Bit or Upgrading Access Authority
(PTE Subject to Atomic Hardware Updates)
If the only change being made to a valid PTE that is subject to
atomic hardware updates is to set the Refer- ence or Change bit to
1 or to add access authorities, a simpler sequence suffices
because the translation hardware will refetch the PTE if an access
is attempted for which the only problems were reference and/or
change bits needing to be set or insufficient access authority.
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
arch/powerpc/include/asm/book3s/64/tlbflush.h | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/powerpc/include/asm/book3s/64/tlbflush.h
b/arch/powerpc/include/asm/book3s/64/tlbflush.h
index 0cac17253513..9c43431e01c5 100644
--- a/arch/powerpc/include/asm/book3s/64/tlbflush.h
+++ b/arch/powerpc/include/asm/book3s/64/tlbflush.h
@@ -137,6 +137,13 @@ static inline void flush_all_mm(struct mm_struct *mm)
#define flush_tlb_page(vma, addr) local_flush_tlb_page(vma, addr)
#define flush_all_mm(mm) local_flush_all_mm(mm)
#endif /* CONFIG_SMP */
+
+#define flush_tlb_fix_spurious_fault flush_tlb_fix_spurious_fault
+static inline void flush_tlb_fix_spurious_fault(struct vm_area_struct *vma,
+ unsigned long address)
+{
+}
+
/*
* flush the page walk cache for the address
*/
--
2.17.0
