powerpc: BookE hardware watchpoint support

This patch implements support for HW based watchpoint via the
DBSR_DAC (Data Address Compare) facility of the BookE processors.

It does so by interfacing with the existing DABR breakpoint code
and adding the necessary bits and pieces for the new bits to
be properly set or cleared

Signed-off-by: Luis Machado <luisgpm@br.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index da52269aec1e..81c8324a4a3c 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -148,7 +148,7 @@ transfer_to_handler:
         /* Check to see if the dbcr0 register is set up to debug.  Use the
            internal debug mode bit to do this. */
         lwz     r12,THREAD_DBCR0(r12)
-        andis.  r12,r12,DBCR0_IDM@h
+        andis.  r12,r12,(DBCR0_IDM  | DBSR_DAC1R | DBSR_DAC1W)@h
         beq+    3f
         /* From user and task is ptraced - load up global dbcr0 */
         li      r12,-1                  /* clear all pending debug events */
@@ -292,7 +292,7 @@ syscall_exit_cont:
         /* If the process has its own DBCR0 value, load it up.  The internal
            debug mode bit tells us that dbcr0 should be loaded. */
         lwz     r0,THREAD+THREAD_DBCR0(r2)
-        andis.  r10,r0,DBCR0_IDM@h
+        andis.  r10,r0,(DBCR0_IDM  | DBSR_DAC1R | DBSR_DAC1W)@h
         bnel-   load_dbcr0
 #endif
 #ifdef CONFIG_44x
@@ -720,7 +720,7 @@ restore_user:
         /* Check whether this process has its own DBCR0 value.  The internal
            debug mode bit tells us that dbcr0 should be loaded. */
         lwz     r0,THREAD+THREAD_DBCR0(r2)
-        andis.  r10,r0,DBCR0_IDM@h
+        andis.  r10,r0,(DBCR0_IDM  | DBSR_DAC1R | DBSR_DAC1W)@h
         bnel-   load_dbcr0
 #endif