[POWERPC] Move to runtime allocated exception stacks
For the additonal exception levels (critical, debug, machine check) on
40x/book-e we were using "static" allocations of the stack in the
associated head.S.
Move to a runtime allocation to make the code a bit easier to read as
we mimic how we handle IRQ stacks. Its also a bit easier to setup the
stack with a "dummy" thread_info in C code.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S
index 8552e67..f2cf60d 100644
--- a/arch/powerpc/kernel/head_40x.S
+++ b/arch/powerpc/kernel/head_40x.S
@@ -148,14 +148,14 @@
mfcr r10; /* save CR in r10 for now */\
mfspr r11,SPRN_SRR3; /* check whether user or kernel */\
andi. r11,r11,MSR_PR; \
- lis r11,critical_stack_top@h; \
- ori r11,r11,critical_stack_top@l; \
+ lis r11,critirq_ctx@ha; \
+ tophys(r11,r11); \
+ lwz r11,critirq_ctx@l(r11); \
beq 1f; \
/* COMING FROM USER MODE */ \
mfspr r11,SPRN_SPRG3; /* if from user, start at top of */\
lwz r11,THREAD_INFO-THREAD(r11); /* this thread's kernel stack */\
- addi r11,r11,THREAD_SIZE; \
-1: subi r11,r11,INT_FRAME_SIZE; /* Allocate an exception frame */\
+1: addi r11,r11,THREAD_SIZE-INT_FRAME_SIZE; /* Alloc an excpt frm */\
tophys(r11,r11); \
stw r10,_CCR(r11); /* save various registers */\
stw r12,GPR12(r11); \
@@ -996,16 +996,6 @@
swapper_pg_dir:
.space PGD_TABLE_SIZE
-
-/* Stack for handling critical exceptions from kernel mode */
- .section .bss
- .align 12
-exception_stack_bottom:
- .space 4096
-critical_stack_top:
- .globl exception_stack_top
-exception_stack_top:
-
/* Room for two PTE pointers, usually the kernel and current user pointers
* to their respective root page table.
*/