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s390: disable preemption when switching to nodat stack with CALL_ON_STACK 

[ Upstream commit 7f28dad395 ]

Make sure preemption is disabled when temporary switching to nodat
stack with CALL_ON_STACK helper, because nodat stack is per cpu.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Vasily Gorbik 2019-11-22 12:19:16 +01:00 committed by Greg Kroah-Hartman
parent 99472d43f4
commit e0ca1ec34d
2 changed files with 11 additions and 3 deletions
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2
arch/s390/kernel/machine_kexec.c
View File

@ -164,7 +164,9 @@ static bool kdump_csum_valid(struct kimage *image)
#ifdef CONFIG_CRASH_DUMP
int rc;
preempt_disable();
rc = CALL_ON_STACK(do_start_kdump, S390_lowcore.nodat_stack, 1, image);
preempt_enable();
return rc == 0;
#else
return false;

12
arch/s390/mm/maccess.c
View File

@ -119,9 +119,15 @@ static unsigned long __no_sanitize_address _memcpy_real(unsigned long dest,
*/
int memcpy_real(void *dest, void *src, size_t count)
{
if (S390_lowcore.nodat_stack != 0)
return CALL_ON_STACK(_memcpy_real, S390_lowcore.nodat_stack,
3, dest, src, count);
int rc;
if (S390_lowcore.nodat_stack != 0) {
preempt_disable();
rc = CALL_ON_STACK(_memcpy_real, S390_lowcore.nodat_stack, 3,
dest, src, count);
preempt_enable();
return rc;
}
/*
* This is a really early memcpy_real call, the stacks are
* not set up yet. Just call _memcpy_real on the early boot