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s390/kasan: support preemptible kernel build 

When the kernel is built with:
CONFIG_PREEMPT=y
CONFIG_PREEMPT_COUNT=y
"stfle" function used by kasan initialization code makes additional
call to preempt_count_add/preempt_count_sub. To avoid removing kasan
instrumentation from sched code where those functions leave split stfle
function and provide __stfle variant without preemption handling to be
used by Kasan.

Reported-by: Benjamin Block <bblock@linux.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Vasily Gorbik 2018-10-19 12:13:58 +02:00 committed by Martin Schwidefsky
parent 63c19be095
commit cf3dbe5dac
2 changed files with 9 additions and 4 deletions
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9
arch/s390/include/asm/facility.h
View File

@ -64,11 +64,10 @@ static inline int test_facility(unsigned long nr)
* @stfle_fac_list: array where facility list can be stored
* @size: size of passed in array in double words
*/
static inline void stfle(u64 *stfle_fac_list, int size)
static inline void __stfle(u64 *stfle_fac_list, int size)
{
unsigned long nr;
preempt_disable();
asm volatile(
" stfl 0(0)\n"
: "=m" (S390_lowcore.stfl_fac_list));
@ -85,6 +84,12 @@ static inline void stfle(u64 *stfle_fac_list, int size)
nr = (reg0 + 1) * 8; /* # bytes stored by stfle */
}
memset((char *) stfle_fac_list + nr, 0, size * 8 - nr);
}
static inline void stfle(u64 *stfle_fac_list, int size)
{
preempt_disable();
__stfle(stfle_fac_list, size);
preempt_enable();
}

4
arch/s390/mm/kasan_init.c
View File

@ -222,8 +222,8 @@ static void __init kasan_enable_dat(void)
static void __init kasan_early_detect_facilities(void)
{
stfle(S390_lowcore.stfle_fac_list,
ARRAY_SIZE(S390_lowcore.stfle_fac_list));
__stfle(S390_lowcore.stfle_fac_list,
ARRAY_SIZE(S390_lowcore.stfle_fac_list));
if (test_facility(8)) {
has_edat = true;
__ctl_set_bit(0, 23);