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| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2016-02-12 12:40:31 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2016-02-17 09:05:04 +0100 |
| commit | 52499d93d6dec3872de3b982219af6d4c182a452 (patch) | |
| tree | 4565561ab51516a02a27bf26438b5de2bd2fc5db | |
| parent | f6c9b160233f9b5afe926b91b55589b706076640 (diff) | |
| download | linux-52499d93d6dec3872de3b982219af6d4c182a452.tar.bz2 | |
s390/maccess: reduce stnsm instructions
When fixing the DAT off bug ("s390: fix DAT off memory access, e.g.
on kdump") both Christian and I missed that we can save an additional
stnsm instruction.
This saves us a couple of cycles which could improve the speed of
memcpy_real.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
| -rw-r--r-- | arch/s390/mm/maccess.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c index 350b0acd7f52..792f9c63fbca 100644 --- a/arch/s390/mm/maccess.c +++ b/arch/s390/mm/maccess.c @@ -93,15 +93,17 @@ static int __memcpy_real(void *dest, void *src, size_t count) */ int memcpy_real(void *dest, void *src, size_t count) { + int irqs_disabled, rc; unsigned long flags; - int rc; if (!count) return 0; - local_irq_save(flags); - __arch_local_irq_stnsm(0xfbUL); + flags = __arch_local_irq_stnsm(0xf8UL); + irqs_disabled = arch_irqs_disabled_flags(flags); + if (!irqs_disabled) + trace_hardirqs_off(); rc = __memcpy_real(dest, src, count); - if (!arch_irqs_disabled_flags(flags)) + if (!irqs_disabled) trace_hardirqs_on(); __arch_local_irq_ssm(flags); return rc; |