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-rw-r--r--arch/riscv/mm/fault.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
index fd7662afddea..3e2708c626a8 100644
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -16,6 +16,7 @@
#include <asm/pgalloc.h>
#include <asm/ptrace.h>
+#include <asm/tlbflush.h>
/*
* This routine handles page faults. It determines the address and the
@@ -265,6 +266,18 @@ vmalloc_fault:
pte_k = pte_offset_kernel(pmd_k, addr);
if (!pte_present(*pte_k))
goto no_context;
+
+ /*
+ * The kernel assumes that TLBs don't cache invalid
+ * entries, but in RISC-V, SFENCE.VMA specifies an
+ * ordering constraint, not a cache flush; it is
+ * necessary even after writing invalid entries.
+ * Relying on flush_tlb_fix_spurious_fault would
+ * suffice, but the extra traps reduce
+ * performance. So, eagerly SFENCE.VMA.
+ */
+ local_flush_tlb_page(addr);
+
return;
}
}