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authorHeiko Carstens <heiko.carstens@de.ibm.com>2012-06-05 09:59:52 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2012-06-14 09:09:02 +0200
commitfbe765680d1fe9d08187ea4dad5041a7955a2c3a (patch)
treecfa5ba11106bb5535552cf6b29ff6aa81f32c606 /arch/s390/kernel/smp.c
parent72f6e3a8bc956fddf6e004ae9b804977d1458e77 (diff)
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 <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel/smp.c')
-rw-r--r--arch/s390/kernel/smp.c16
1 files changed, 7 insertions, 9 deletions
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 (;;) ;