ARM: bitops: ensure set/clear/change bitops take a word-aligned pointer

Add additional instructions to our assembly bitops functions to ensure
that they only operate on word-aligned pointers.  This will be necessary
when we switch these operations to use the word-based exclusive
operations.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/arm/lib/bitops.h b/arch/arm/lib/bitops.h
index d42252918bfb..bd00551fb797 100644
--- a/arch/arm/lib/bitops.h
+++ b/arch/arm/lib/bitops.h
@@ -1,6 +1,8 @@
 
 #if __LINUX_ARM_ARCH__ >= 6 && defined(CONFIG_CPU_32v6K)
         .macro  bitop, instr
+        ands    ip, r1, #3
+        strneb  r1, [ip]                @ assert word-aligned
         mov     r2, #1
         and     r3, r0, #7              @ Get bit offset
         add     r1, r1, r0, lsr #3      @ Get byte offset
@@ -14,6 +16,8 @@
         .endm
 
         .macro  testop, instr, store
+        ands    ip, r1, #3
+        strneb  r1, [ip]                @ assert word-aligned
         and     r3, r0, #7              @ Get bit offset
         mov     r2, #1
         add     r1, r1, r0, lsr #3      @ Get byte offset
@@ -32,6 +36,8 @@
         .endm
 #else
         .macro  bitop, instr
+        ands    ip, r1, #3
+        strneb  r1, [ip]                @ assert word-aligned
         and     r2, r0, #7
         mov     r3, #1
         mov     r3, r3, lsl r2
@@ -52,6 +58,8 @@
  * to avoid dirtying the data cache.
  */
         .macro  testop, instr, store
+        ands    ip, r1, #3
+        strneb  r1, [ip]                @ assert word-aligned
         add     r1, r1, r0, lsr #3
         and     r3, r0, #7
         mov     r0, #1