From fbe765680d1fe9d08187ea4dad5041a7955a2c3a Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 5 Jun 2012 09:59:52 +0200 Subject: s390/smp: make absolute lowcore / cpu restart parameter accesses more robust Setting the cpu restart parameters is done in three different fashions: - directly setting the four parameters individually - copying the four parameters with memcpy (using 4 * sizeof(long)) - copying the four parameters using a private structure In addition code in entry*.S relies on a certain order of the restart members of struct _lowcore. Make all of this more robust to future changes by adding a mem_absolute_assign(dest, val) define, which assigns val to dest using absolute addressing mode. Also the load multiple instructions in entry*.S have been split into separate load instruction so the order of the struct _lowcore members doesn't matter anymore. In addition move the prototypes of memcpy_real/absolute from uaccess.h to processor.h. These memcpy* variants are not related to uaccess at all. string.h doesn't seem to match as well, so lets use processor.h. Also replace the eight byte array in struct _lowcore which represents a misaliged u64 with a u64. The compiler will always create code that handles the misaligned u64 correctly. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/smp.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) (limited to 'arch/s390/kernel/smp.c') diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index e01408429ad..dc602a61233 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -273,26 +273,24 @@ static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *), void *data, unsigned long stack) { struct _lowcore *lc = lowcore_ptr[pcpu - pcpu_devices]; - struct { - unsigned long stack; - void *func; - void *data; - unsigned long source; - } restart = { stack, func, data, stap() }; + unsigned long source_cpu = stap(); __load_psw_mask(psw_kernel_bits); - if (pcpu->address == restart.source) + if (pcpu->address == source_cpu) 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. */ - memcpy_absolute(&lc->restart_stack, &restart, sizeof(restart)); + 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); asm volatile( "0: sigp 0,%0,%2 # sigp restart to target cpu\n" " brc 2,0b # busy, try again\n" "1: sigp 0,%1,%3 # sigp stop to current cpu\n" " brc 2,1b # busy, try again\n" - : : "d" (pcpu->address), "d" (restart.source), + : : "d" (pcpu->address), "d" (source_cpu), "K" (SIGP_RESTART), "K" (SIGP_STOP) : "0", "1", "cc"); for (;;) ; -- cgit v1.2.3-70-g09d2