[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.

[ [email protected]: Fixed bug on 6xx where we need to reload r9 with the
  thread_info pointer. ]

Signed-off-by: Kumar Gala <[email protected]>
Signed-off-by: Paul Mackerras <[email protected]>
This commit is contained in:
Kumar Gala 2008-04-28 16:21:22 +10:00 • committed by Paul Mackerras
commit 85218827cc
8 changed files with 66 additions and 5 deletions

View file

@ -138,6 +138,8 @@ typedef struct {
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 @@ struct thread_struct {
#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 @@ struct thread_struct {
#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}, \