diff options
| author | ShihPo Hung | 2019-06-17 12:26:17 +0800 |
|---|---|---|
| committer | Paul Walmsley | 2019-06-17 03:44:44 -0700 |
| commit | bf587caae305ae3b4393077fb22c98478ee55755 (patch) | |
| tree | ab59e43380e7b8e32b79875eb26a5c27e5046957 /arch/riscv/mm/fault.c | |
| parent | c35f1b87fc595807ff15d2834d241f9771497205 (diff) | |
riscv: mm: synchronize MMU after pte change
Because RISC-V compliant implementations can cache invalid entries
in TLB, an SFENCE.VMA is necessary after changes to the page table.
This patch adds an SFENCE.vma for the vmalloc_fault path.
Signed-off-by: ShihPo Hung <shihpo.hung@sifive.com>
[paul.walmsley@sifive.com: reversed tab->whitespace conversion,
wrapped comment lines]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: linux-riscv@lists.infradead.org
Cc: stable@vger.kernel.org
Diffstat (limited to 'arch/riscv/mm/fault.c')
| -rw-r--r-- | arch/riscv/mm/fault.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c index cec8be9e2d6a..5b72e60c5a6b 100644 --- a/arch/riscv/mm/fault.c +++ b/arch/riscv/mm/fault.c @@ -29,6 +29,7 @@ #include <asm/pgalloc.h> #include <asm/ptrace.h> +#include <asm/tlbflush.h> /* * This routine handles page faults. It determines the address and the @@ -278,6 +279,18 @@ 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; } } |