[PATCH] s390: packed stack vs. cpu hotplug.
From: Martin Schwidefsky <[email protected]>
The different stack frame layout for packed stacks broke cpu hotplug.
Recreate the initial stack frame of the idle thread for offline cpus
coming back online. Reenable interrupts after loading the initial
registers. In addition this patch contains two more bug fixes:
a typo for 64 bit (__SMALL_STACK_SIZE vs. __SMALL_STACK) and
show_trace didn't show a trace if for task == NULL.
Signed-off-by: Martin Schwidefsky <[email protected]>
diffstat:
arch/s390/kernel/entry.S | 2 +-
arch/s390/kernel/entry64.S | 2 +-
arch/s390/kernel/smp.c | 8 +++++++-
arch/s390/kernel/traps.c | 4 ++--
include/asm-s390/thread_info.h | 2 +-
5 files changed, 12 insertions(+), 6 deletions(-)
diff -urN linux-2.6/arch/s390/kernel/entry.S linux-2.6-s390/arch/s390/kernel/entry.S
--- linux-2.6/arch/s390/kernel/entry.S Fri Sep 3 15:26:11 2004
+++ linux-2.6-s390/arch/s390/kernel/entry.S Fri Sep 3 15:26:30 2004
@@ -602,8 +602,8 @@
l %r15,__LC_SAVE_AREA+60 # load ksp
lctl %c0,%c15,__LC_CREGS_SAVE_AREA # get new ctl regs
lam %a0,%a15,__LC_AREGS_SAVE_AREA
- stosm 0(%r15),0x04 # now we can turn dat on
lm %r6,%r15,__SF_GPRS(%r15) # load registers from clone
+ stosm __SF_EMPTY(%r15),0x04 # now we can turn dat on
basr %r14,0
l %r14,restart_addr-.(%r14)
br %r14 # branch to start_secondary
diff -urN linux-2.6/arch/s390/kernel/entry64.S linux-2.6-s390/arch/s390/kernel/entry64.S
--- linux-2.6/arch/s390/kernel/entry64.S Fri Sep 3 15:26:11 2004
+++ linux-2.6-s390/arch/s390/kernel/entry64.S Fri Sep 3 15:26:30 2004
@@ -644,8 +644,8 @@
lctlg %c0,%c15,0(%r10) # get new ctl regs
lghi %r10,__LC_AREGS_SAVE_AREA
lam %a0,%a15,0(%r10)
- stosm 0(%r15),0x04 # now we can turn dat on
lmg %r6,%r15,__SF_GPRS(%r15) # load registers from clone
+ stosm __SF_EMPTY(%r15),0x04 # now we can turn dat on
jg start_secondary
#else
/*
diff -urN linux-2.6/arch/s390/kernel/smp.c linux-2.6-s390/arch/s390/kernel/smp.c
--- linux-2.6/arch/s390/kernel/smp.c Fri Sep 3 15:26:11 2004
+++ linux-2.6-s390/arch/s390/kernel/smp.c Fri Sep 3 15:26:30 2004
@@ -637,6 +637,7 @@
{
struct task_struct *idle;
struct _lowcore *cpu_lowcore;
+ struct stack_frame *sf;
sigp_ccode ccode;
int curr_cpu;
@@ -660,9 +661,14 @@
idle = current_set[cpu];
cpu_lowcore = lowcore_ptr[cpu];
- cpu_lowcore->save_area[15] = idle->thread.ksp;
cpu_lowcore->kernel_stack = (unsigned long)
idle->thread_info + (THREAD_SIZE);
+ sf = (struct stack_frame *) (cpu_lowcore->kernel_stack
+ - sizeof(struct pt_regs)
+ - sizeof(struct stack_frame));
+ memset(sf, 0, sizeof(struct stack_frame));
+ sf->gprs[9] = (unsigned long) sf;
+ cpu_lowcore->save_area[15] = (unsigned long) sf;
__ctl_store(cpu_lowcore->cregs_save_area[0], 0, 15);
__asm__ __volatile__("stam 0,15,0(%0)"
: : "a" (&cpu_lowcore->access_regs_save_area)
diff -urN linux-2.6/arch/s390/kernel/traps.c linux-2.6-s390/arch/s390/kernel/traps.c
--- linux-2.6/arch/s390/kernel/traps.c Fri Sep 3 15:26:11 2004
+++ linux-2.6-s390/arch/s390/kernel/traps.c Fri Sep 3 15:26:30 2004
@@ -138,8 +138,8 @@
__show_trace(sp, (unsigned long) task->thread_info,
(unsigned long) task->thread_info + THREAD_SIZE);
else
- __show_trace(sp, S390_lowcore.thread_info - THREAD_SIZE,
- S390_lowcore.thread_info);
+ __show_trace(sp, S390_lowcore.thread_info,
+ S390_lowcore.thread_info + THREAD_SIZE);
printk("\n");
}
diff -urN linux-2.6/include/asm-s390/thread_info.h linux-2.6-s390/include/asm-s390/thread_info.h
--- linux-2.6/include/asm-s390/thread_info.h Fri Sep 3 15:26:16 2004
+++ linux-2.6-s390/include/asm-s390/thread_info.h Fri Sep 3 15:26:30 2004
@@ -23,7 +23,7 @@
#define ASYNC_ORDER 0
#endif
#else /* __s390x__ */
-#ifndef __SMALL_STACK_STACK
+#ifndef __SMALL_STACK
#define THREAD_ORDER 2
#define ASYNC_ORDER 2
#else