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authorMichael Holzheu <holzheu@linux.vnet.ibm.com>2012-05-24 14:38:26 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2012-05-30 09:04:51 +0200
commit061da3dfb291570e780169918933ba51c2b7d554 (patch)
tree6f41ed465199eb7c5a8b31ff6b834c0b5aa2565e /arch
parent73bf463efaba6a1efe69349c6d7275d03468adf4 (diff)
downloadlinux-061da3dfb291570e780169918933ba51c2b7d554.tar.gz
s390/kernel: Fix smp_call_ipl_cpu() for offline CPUs
If the IPL CPU is offline, currently the pcpu_delegate() function used by smp_call_ipl_cpu() does not work because pcpu_delegate() modifies the lowcore of the target CPU. In case of an offline IPL CPU currently the prefix register is zero but pcpu->lowcore still points to the old prefix page. Therefore the lowcore changes done by pcpu_delegate() have no effect. With this fix pcpu_delegate() now uses memcpy_absolute() and therefore also prepares the absolute zero lowcore if the target CPU has prefix register zero. Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/s390/kernel/smp.c19
1 files changed, 10 insertions, 9 deletions
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 9948bd09ee5..5c7bf24849b 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -297,26 +297,27 @@ static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
void *data, unsigned long stack)
{
- struct _lowcore *lc = pcpu->lowcore;
- unsigned short this_cpu;
+ struct _lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
+ struct {
+ unsigned long stack;
+ void *func;
+ void *data;
+ unsigned long source;
+ } restart = { stack, func, data, stap() };
__load_psw_mask(psw_kernel_bits);
- this_cpu = stap();
- if (pcpu->address == this_cpu)
+ if (pcpu->address == restart.source)
func(data); /* should not return */
/* Stop target cpu (if func returns this stops the current cpu). */
pcpu_sigp_retry(pcpu, sigp_stop, 0);
/* Restart func on the target cpu and stop the current cpu. */
- lc->restart_stack = stack;
- lc->restart_fn = (unsigned long) func;
- lc->restart_data = (unsigned long) data;
- lc->restart_source = (unsigned long) this_cpu;
+ memcpy_absolute(&lc->restart_stack, &restart, sizeof(restart));
asm volatile(
"0: sigp 0,%0,6 # sigp restart to target cpu\n"
" brc 2,0b # busy, try again\n"
"1: sigp 0,%1,5 # sigp stop to current cpu\n"
" brc 2,1b # busy, try again\n"
- : : "d" (pcpu->address), "d" (this_cpu) : "0", "1", "cc");
+ : : "d" (pcpu->address), "d" (restart.source) : "0", "1", "cc");
for (;;) ;
}