[Qemu-devel] [PATCH 4/5] ARM BE32 watchpoint fix.

[Julian Brown]

In BE32 mode, sub-word size watchpoints can fail to trigger because the
address of the access is adjusted in the opcode helpers before being
compared with the watchpoint registers.  This patch reversed the address
adjustment before performing the comparison.

Signed-off-by: Julian Brown <address@hidden>
---
 exec.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/exec.c b/exec.c
index 4c84389..eadab54 100644
--- a/exec.c
+++ b/exec.c
@@ -2047,6 +2047,19 @@ static void check_watchpoint(int offset, int len, 
MemTxAttrs attrs, int flags)
         return;
     }
     vaddr = (cpu->mem_io_vaddr & TARGET_PAGE_MASK) + offset;
+#if defined(TARGET_ARM) && !defined(CONFIG_USER_ONLY)
+    /* In BE32 system mode, target memory is stored byteswapped (FIXME:
+       relative to a little-endian host system), and by the time we reach here
+       (via an opcode helper) the addresses of subword accesses have been
+       adjusted to account for that, which means that watchpoints will not
+       match.  Undo the adjustment here.  */
+    if (arm_sctlr_b(env)) {
+        if (len == 1)
+            vaddr ^= 3;
+        else if (len == 2)
+            vaddr ^= 2;
+    }
+#endif
     QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) {
         if (cpu_watchpoint_address_matches(wp, vaddr, len)
             && (wp->flags & flags)) {
-- 
1.9.1