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, 17 insertions, 2 deletions

diff --git a/arch/arm/mm/cache-v7.S b/arch/arm/mm/cache-v7.S
index bda0ec31a4e2..e1bd9759617f 100644
--- a/arch/arm/mm/cache-v7.S
+++ b/arch/arm/mm/cache-v7.S
@@ -13,6 +13,7 @@
 #include <linux/linkage.h>
 #include <linux/init.h>
 #include <asm/assembler.h>
+#include <asm/unwind.h>
 
 #include "proc-macros.S"
 
@@ -153,13 +154,16 @@ ENTRY(v7_coherent_kern_range)
  *      - the Icache does not read data from the write buffer
  */
 ENTRY(v7_coherent_user_range)
+ UNWIND(.fnstart                )
         dcache_line_size r2, r3
         sub     r3, r2, #1
         bic     r0, r0, r3
-1:      mcr     p15, 0, r0, c7, c11, 1          @ clean D line to the point of unification
+1:
+ USER(  mcr     p15, 0, r0, c7, c11, 1  )       @ clean D line to the point of unification
         dsb
-        mcr     p15, 0, r0, c7, c5, 1           @ invalidate I line
+ USER(  mcr     p15, 0, r0, c7, c5, 1   )       @ invalidate I line
         add     r0, r0, r2
+2:
         cmp     r0, r1
         blo     1b
         mov     r0, #0
@@ -167,6 +171,17 @@ ENTRY(v7_coherent_user_range)
         dsb
         isb
         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(v7_coherent_kern_range)
 ENDPROC(v7_coherent_user_range)