powerpc: Set stack limit properly in crit_transfer_to_handler

Commit 9778b696a0188ad3b3524b383953ee73b31b7b68 incorrectly
changes the code setting the stack limit on entry to the
kernel to mark the thread_info at the bottom of the stack
out of bounds anymore. This fixes it.

Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 10 insertions, 2 deletions

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 5207d5a405e2..ead5016b02d0 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -89,10 +89,14 @@ crit_transfer_to_handler:
         mfspr   r0,SPRN_SRR1
         stw     r0,_SRR1(r11)
 
+        /* set the stack limit to the current stack
+         * and set the limit to protect the thread_info
+         * struct
+         */
         mfspr   r8,SPRN_SPRG_THREAD
         lwz     r0,KSP_LIMIT(r8)
         stw     r0,SAVED_KSP_LIMIT(r11)
-        CURRENT_THREAD_INFO(r0, r1)
+        rlwimi  r0,r1,0,0,(31-THREAD_SHIFT)
         stw     r0,KSP_LIMIT(r8)
         /* fall through */
 #endif
@@ -109,10 +113,14 @@ crit_transfer_to_handler:
         mfspr   r0,SPRN_SRR1
         stw     r0,crit_srr1@l(0)
 
+        /* set the stack limit to the current stack
+         * and set the limit to protect the thread_info
+         * struct
+         */
         mfspr   r8,SPRN_SPRG_THREAD
         lwz     r0,KSP_LIMIT(r8)
         stw     r0,saved_ksp_limit@l(0)
-        CURRENT_THREAD_INFO(r0, r1)
+        rlwimi  r0,r1,0,0,(31-THREAD_SHIFT)
         stw     r0,KSP_LIMIT(r8)
         /* fall through */
 #endif