On Tue, May 18, 2021 at 5:00 PM Mark Rutland [off-list ref] wrote:

On Mon, May 17, 2021 at 08:51:13AM +0100, Fuad Tabba wrote:

quoted

The uaccess toggle isn't part of the cache maintenance operation.
Move it directly to where it's needed.

No functional change intended.

Signed-off-by: Fuad Tabba <redacted>
---
 arch/arm64/mm/cache.S | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
index 6babaaf34f17..d74b20cd6449 100644
--- a/arch/arm64/mm/cache.S
+++ b/arch/arm64/mm/cache.S

@@ -26,9 +26,6 @@
  *   - needs_uaccess - (macro parameter) might access user space memory
  */
 .macro       __flush_cache_range, needs_uaccess
-     .if     \needs_uaccess
-     uaccess_ttbr0_enable x2, x3, x4
-     .endif
 alternative_if ARM64_HAS_CACHE_IDC
      dsb     ishst
      b       7f

@@ -55,9 +52,6 @@ alternative_else_nop_endif
      invalidate_icache_by_line x0, x1, x2, x3, \needs_uaccess, 9f
 8:   mov     x0, #0
 1:
-     .if     \needs_uaccess
-     uaccess_ttbr0_disable x1, x2
-     .endif
      ret

      .if     \needs_uaccess

@@ -92,7 +86,9 @@ SYM_FUNC_END(__flush_icache_range)
  *   - end     - virtual end address of region
  */
 SYM_FUNC_START(__flush_cache_user_range)
+     uaccess_ttbr0_enable x2, x3, x4
      __flush_cache_range needs_uaccess=1
+     uaccess_ttbr0_disable x1, x2
 SYM_FUNC_END(__flush_cache_user_range)

The RET is still in the __flush_cache_range macro, so I don't think
we'll ever execute the uaccess_ttbr0_disable step here.

Yes. Like you suggested earlier, it's moving out of the macro.

Thanks,
/fuad

Mark.

quoted

 /*
--
2.31.1.751.gd2f1c929bd-goog

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