[POWERPC] Make Book-E debug handling SMP safe

global_dbcr0 needs to be a per cpu set of save areas instead of a single
global on all processors.

Also, we switch to using DBCR0_IDM to determine if the user space app is
being debugged as its a more consistent way.  In the future we should
support features like hardware breakpoint and watchpoints which will
have DBCR0_IDM set but not necessarily DBCR0_IC (single step).

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

1 files changed, 21 insertions, 9 deletions

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 69a91bd46115..84c868633068 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -110,9 +110,9 @@ transfer_to_handler:
         stw     r11,PT_REGS(r12)
 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
         /* Check to see if the dbcr0 register is set up to debug.  Use the
-           single-step bit to do this. */
+           internal debug mode bit to do this. */
         lwz     r12,THREAD_DBCR0(r12)
-        andis.  r12,r12,DBCR0_IC@h
+        andis.  r12,r12,DBCR0_IDM@h
         beq+    3f
         /* From user and task is ptraced - load up global dbcr0 */
         li      r12,-1                  /* clear all pending debug events */
@@ -120,6 +120,12 @@ transfer_to_handler:
         lis     r11,global_dbcr0@ha
         tophys(r11,r11)
         addi    r11,r11,global_dbcr0@l
+#ifdef CONFIG_SMP
+        rlwinm  r9,r1,0,0,(31-THREAD_SHIFT)
+        lwz     r9,TI_CPU(r9)
+        slwi    r9,r9,3
+        add     r11,r11,r9
+#endif
         lwz     r12,0(r11)
         mtspr   SPRN_DBCR0,r12
         lwz     r12,4(r11)
@@ -238,10 +244,10 @@ ret_from_syscall:
         stw     r11,_CCR(r1)
 syscall_exit_cont:
 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
-        /* If the process has its own DBCR0 value, load it up.  The single
-           step bit tells us that dbcr0 should be loaded. */
+        /* 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_IC@h
+        andis.  r10,r0,DBCR0_IDM@h
         bnel-   load_dbcr0
 #endif
 #ifdef CONFIG_44x
@@ -666,10 +672,10 @@ user_exc_return:		/* r10 contains MSR_KERNEL here */
 
 restore_user:
 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
-        /* Check whether this process has its own DBCR0 value.  The single
-           step bit tells us that dbcr0 should be loaded. */
+        /* 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_IC@h
+        andis.  r10,r0,DBCR0_IDM@h
         bnel-   load_dbcr0
 #endif
 
@@ -879,6 +885,12 @@ load_dbcr0:
         mfspr   r10,SPRN_DBCR0
         lis     r11,global_dbcr0@ha
         addi    r11,r11,global_dbcr0@l
+#ifdef CONFIG_SMP
+        rlwinm  r9,r1,0,0,(31-THREAD_SHIFT)
+        lwz     r9,TI_CPU(r9)
+        slwi    r9,r9,3
+        add     r11,r11,r9
+#endif
         stw     r10,0(r11)
         mtspr   SPRN_DBCR0,r0
         lwz     r10,4(r11)
@@ -891,7 +903,7 @@ load_dbcr0:
         .section .bss
         .align  4
 global_dbcr0:
-        .space  8
+        .space  8*NR_CPUS
         .previous
 #endif /* !(CONFIG_4xx || CONFIG_BOOKE) */