[ARM] 3352/1: DSB required for the completion of a TLB maintenance operation

Patch from Catalin Marinas

Chapter B2.7.3 in the latest ARM ARM (with v6 information) states that
the completion of a TLB maintenance operation is only guaranteed by
the execution of a DSB (Data Syncronization Barrier, formerly Data
Write Barrier or Drain Write Buffer).

Note that a DSB is only needed in the flush_tlb_kernel_* functions
since the completion is guaranteed by a mode change (i.e. switching
back to user mode) for the flush_tlb_user_* functions.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/arm/mm/tlb-v6.S b/arch/arm/mm/tlb-v6.S
index 6f76b89ef46e..fd6adde39091 100644
--- a/arch/arm/mm/tlb-v6.S
+++ b/arch/arm/mm/tlb-v6.S
@@ -80,6 +80,7 @@ ENTRY(v6wbi_flush_kern_tlb_range)
         add     r0, r0, #PAGE_SZ
         cmp     r0, r1
         blo     1b
+        mcr     p15, 0, r2, c7, c10, 4          @ data synchronization barrier
         mov     pc, lr
 
         .section ".text.init", #alloc, #execinstr