From: Anton Blanchard <anton@samba.org>
Fix __get_SP()
__get_SP used to be a function call which meant we allocated a stack
frame before calling it. This meant the SP it returned was one frame
below the current function. Lets call that bogusSP (and the real one
SP).
The new dump_stack was being tail call optimised so it remained one
frame above bogusSP. dump_stack would then store below SP (as the ABI
allows us to) and would stomp over the back link that bogusSP pointed
to (__get_SP had set the back link up so it worked sometimes, just not
all the time).
Fix this by just making __get_SP an inline that returns the current SP.
---
arch/ppc64/kernel/irq.c | 2 +-
arch/ppc64/kernel/misc.S | 4 ----
arch/ppc64/kernel/process.c | 8 ++++----
arch/ppc64/kernel/stab.c | 2 +-
include/asm-ppc64/processor.h | 3 ++-
5 files changed, 8 insertions(+), 11 deletions(-)
diff -puN arch/ppc64/kernel/irq.c~ppc64-get_SP arch/ppc64/kernel/irq.c
--- 25/arch/ppc64/kernel/irq.c~ppc64-get_SP 2004-02-21 20:58:31.000000000 -0800
+++ 25-akpm/arch/ppc64/kernel/irq.c 2004-02-21 20:58:31.000000000 -0800
@@ -579,7 +579,7 @@ int do_IRQ(struct pt_regs *regs)
{
long sp;
- sp = (unsigned long)_get_SP() & (THREAD_SIZE-1);
+ sp = __get_SP() & (THREAD_SIZE-1);
if (unlikely(sp < (sizeof(struct thread_info) + 8192))) {
printk("do_IRQ: stack overflow: %ld\n",
diff -puN arch/ppc64/kernel/misc.S~ppc64-get_SP arch/ppc64/kernel/misc.S
--- 25/arch/ppc64/kernel/misc.S~ppc64-get_SP 2004-02-21 20:58:31.000000000 -0800
+++ 25-akpm/arch/ppc64/kernel/misc.S 2004-02-21 20:58:31.000000000 -0800
@@ -383,10 +383,6 @@ _GLOBAL(abs)
neg r3,r3
10: blr
-_GLOBAL(_get_SP)
- mr r3,r1 /* Close enough */
- blr
-
_GLOBAL(_get_PVR)
mfspr r3,PVR
blr
diff -puN arch/ppc64/kernel/process.c~ppc64-get_SP arch/ppc64/kernel/process.c
--- 25/arch/ppc64/kernel/process.c~ppc64-get_SP 2004-02-21 20:58:31.000000000 -0800
+++ 25-akpm/arch/ppc64/kernel/process.c 2004-02-21 20:58:31.000000000 -0800
@@ -162,7 +162,7 @@ struct task_struct *__switch_to(struct t
* for that first.
*/
if ((cur_cpu_spec->cpu_features & CPU_FTR_SLB) &&
- GET_ESID((unsigned long)_get_SP()) != GET_ESID(PAGE_OFFSET)) {
+ GET_ESID(__get_SP()) != GET_ESID(PAGE_OFFSET)) {
union {
unsigned long word0;
slb_dword0 data;
@@ -171,7 +171,7 @@ struct task_struct *__switch_to(struct t
esid_data.word0 = 0;
/* class bit is in valid field for slbie instruction */
esid_data.data.v = 1;
- esid_data.data.esid = GET_ESID((unsigned long)_get_SP());
+ esid_data.data.esid = GET_ESID(__get_SP());
asm volatile("isync; slbie %0; isync" : : "r" (esid_data));
}
local_irq_restore(flags);
@@ -528,7 +528,7 @@ void show_stack(struct task_struct *p, u
if (p) {
sp = p->thread.ksp;
} else {
- sp = (unsigned long)_get_SP();
+ sp = __get_SP();
p = current;
}
}
@@ -549,7 +549,7 @@ void show_stack(struct task_struct *p, u
void dump_stack(void)
{
- show_stack(current, (unsigned long *)_get_SP());
+ show_stack(current, (unsigned long *)__get_SP());
}
EXPORT_SYMBOL(dump_stack);
diff -puN arch/ppc64/kernel/stab.c~ppc64-get_SP arch/ppc64/kernel/stab.c
--- 25/arch/ppc64/kernel/stab.c~ppc64-get_SP 2004-02-21 20:58:31.000000000 -0800
+++ 25-akpm/arch/ppc64/kernel/stab.c 2004-02-21 20:58:31.000000000 -0800
@@ -324,7 +324,7 @@ static void make_slbe(unsigned long esid
castout_entry = 1;
asm volatile("slbmfee %0,%1" : "=r" (esid_data) : "r" (entry));
} while (esid_data.data.v &&
- esid_data.data.esid == GET_ESID((unsigned long)_get_SP()));
+ esid_data.data.esid == GET_ESID(__get_SP()));
get_paca()->xStab_data.next_round_robin = castout_entry;
diff -puN include/asm-ppc64/processor.h~ppc64-get_SP include/asm-ppc64/processor.h
--- 25/include/asm-ppc64/processor.h~ppc64-get_SP 2004-02-21 20:58:31.000000000 -0800
+++ 25-akpm/include/asm-ppc64/processor.h 2004-02-21 20:58:31.000000000 -0800
@@ -475,7 +475,8 @@ static inline void set_tb(unsigned int u
mttbl(lower);
}
-extern unsigned long *_get_SP(void);
+#define __get_SP() ({unsigned long sp; \
+ asm volatile("mr %0,1": "=r" (sp)); sp;})
extern int have_of;
_