ARM: 5746/1: Handle possible translation errors in ARMv6/v7 coherent_user_range

This is needed because applications using the sys_cacheflush system call
can pass a memory range which isn't mapped yet even though the
corresponding vma is valid. The patch also adds unwinding annotations
for correct backtraces from the coherent_user_range() functions.

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

1 files changed, 18 insertions, 2 deletions

diff --git a/arch/arm/mm/cache-v6.S b/arch/arm/mm/cache-v6.S
index 8f5c13f4c936..295e25dd6381 100644
--- a/arch/arm/mm/cache-v6.S
+++ b/arch/arm/mm/cache-v6.S
@@ -12,6 +12,7 @@
 #include <linux/linkage.h>
 #include <linux/init.h>
 #include <asm/assembler.h>
+#include <asm/unwind.h>
 
 #include "proc-macros.S"
 
@@ -121,11 +122,13 @@ ENTRY(v6_coherent_kern_range)
  *      - the Icache does not read data from the write buffer
  */
 ENTRY(v6_coherent_user_range)
-
+ UNWIND(.fnstart                )
 #ifdef HARVARD_CACHE
         bic     r0, r0, #CACHE_LINE_SIZE - 1
-1:      mcr     p15, 0, r0, c7, c10, 1          @ clean D line
+1:
+ USER(  mcr     p15, 0, r0, c7, c10, 1  )       @ clean D line
         add     r0, r0, #CACHE_LINE_SIZE
+2:
         cmp     r0, r1
         blo     1b
 #endif
@@ -143,6 +146,19 @@ ENTRY(v6_coherent_user_range)
         mov     pc, lr
 
 /*
+ * Fault handling for the cache operation above. If the virtual address in r0
+ * isn't mapped, just try the next page.
+ */
+9001:
+        mov     r0, r0, lsr #12
+        mov     r0, r0, lsl #12
+        add     r0, r0, #4096
+        b       2b
+ UNWIND(.fnend          )
+ENDPROC(v6_coherent_user_range)
+ENDPROC(v6_coherent_kern_range)
+
+/*
  *      v6_flush_kern_dcache_page(kaddr)
  *
  *      Ensure that the data held in the page kaddr is written back