[POWERPC] Add IRQSTACKS support on ppc32
This makes it possible to use separate stacks for hard and soft IRQs
on 32-bit powerpc as well as on 64-bit. The code for 32-bit is just
the 32-bit analog of the 64-bit code.
* Added allocation and initialization of the irq stacks. We limit the
stacks to be in lowmem for ppc32.
* Implemented ppc32 versions of call_do_softirq() and call_handle_irq()
to switch the stack pointers
* Reworked how we do stack overflow detection. We now keep around the
limit of the stack in the thread_struct and compare against the limit
to see if we've overflowed. We can now use this on ppc64 if desired.
[ paulus@samba.org: Fixed bug on 6xx where we need to reload r9 with the
thread_info pointer. ]
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/include/asm-powerpc/processor.h b/include/asm-powerpc/processor.h
index fd98ca9..cf83f2d 100644
--- a/include/asm-powerpc/processor.h
+++ b/include/asm-powerpc/processor.h
@@ -138,6 +138,8 @@
struct thread_struct {
unsigned long ksp; /* Kernel stack pointer */
+ unsigned long ksp_limit; /* if ksp <= ksp_limit stack overflow */
+
#ifdef CONFIG_PPC64
unsigned long ksp_vsid;
#endif
@@ -182,11 +184,14 @@
#define ARCH_MIN_TASKALIGN 16
#define INIT_SP (sizeof(init_stack) + (unsigned long) &init_stack)
+#define INIT_SP_LIMIT \
+ (_ALIGN_UP(sizeof(init_thread_info), 16) + (unsigned long) &init_stack)
#ifdef CONFIG_PPC32
#define INIT_THREAD { \
.ksp = INIT_SP, \
+ .ksp_limit = INIT_SP_LIMIT, \
.fs = KERNEL_DS, \
.pgdir = swapper_pg_dir, \
.fpexc_mode = MSR_FE0 | MSR_FE1, \
@@ -194,6 +199,7 @@
#else
#define INIT_THREAD { \
.ksp = INIT_SP, \
+ .ksp_limit = INIT_SP_LIMIT, \
.regs = (struct pt_regs *)INIT_SP - 1, /* XXX bogus, I think */ \
.fs = KERNEL_DS, \
.fpr = {0}, \