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| author | Alexander Gordeev <agordeev@linux.ibm.com> | 2022-03-17 15:03:01 +0100 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2022-03-27 22:18:39 +0200 |
| commit | dc2ab23b992c9d5dab93b9bf01b10b10465e537e (patch) | |
| tree | 654570d5808bf8caebf58541b1d459501a1af726 /arch/s390/kernel/smp.c | |
| parent | s390/test_unwind: verify __kretprobe_trampoline is replaced (diff) | |
| download | linux-dc2ab23b992c9d5dab93b9bf01b10b10465e537e.tar.xz linux-dc2ab23b992c9d5dab93b9bf01b10b10465e537e.zip | |
s390/smp: cleanup target CPU callback starting
Macro mem_assign_absolute() is used to initialize a target
CPU lowcore callback parameters. But despite the macro name
it writes to the absolute lowcore only if the target CPU is
offline. In case the CPU is online the macro does implicitly
write to the normal memory.
That behaviour is correct, but extremely subtle. Sacrifice
few program bits in favour of clarity and distinguish between
online vs offline CPUs and normal vs absolute lowcore pointer.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390/kernel/smp.c')
| -rw-r--r-- | arch/s390/kernel/smp.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 127da1850b06..b7e56fabe387 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -326,10 +326,17 @@ static void pcpu_delegate(struct pcpu *pcpu, /* 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. */ - mem_assign_absolute(lc->restart_stack, stack); - mem_assign_absolute(lc->restart_fn, (unsigned long) func); - mem_assign_absolute(lc->restart_data, (unsigned long) data); - mem_assign_absolute(lc->restart_source, source_cpu); + if (lc) { + lc->restart_stack = stack; + lc->restart_fn = (unsigned long)func; + lc->restart_data = (unsigned long)data; + lc->restart_source = source_cpu; + } else { + mem_assign_absolute(lc->restart_stack, stack); + mem_assign_absolute(lc->restart_fn, (unsigned long)func); + mem_assign_absolute(lc->restart_data, (unsigned long)data); + mem_assign_absolute(lc->restart_source, source_cpu); + } __bpon(); asm volatile( "0: sigp 0,%0,%2 # sigp restart to target cpu\n" |