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| author | Michael Holzheu <holzheu@linux.vnet.ibm.com> | 2012-05-24 14:38:26 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2012-05-30 09:04:51 +0200 |
| commit | 061da3dfb291570e780169918933ba51c2b7d554 (patch) | |
| tree | 6f41ed465199eb7c5a8b31ff6b834c0b5aa2565e /arch/s390 | |
| parent | 73bf463efaba6a1efe69349c6d7275d03468adf4 (diff) | |
| download | linux-061da3dfb291570e780169918933ba51c2b7d554.tar.bz2 | |
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/s390')
| -rw-r--r-- | arch/s390/kernel/smp.c | 19 |
1 files changed, 10 insertions, 9 deletions
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 9948bd09ee57..5c7bf24849b2 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 (;;) ; } |