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s390/smp: enforce lowcore protection on CPU restart 

As result of commit 915fea04f9 ("s390/smp: enable DAT before
CPU restart callback is called") the low-address protection bit
gets mistakenly unset in control register 0 save area of the
absolute zero memory. That area is used when manual PSW restart
happened to hit an offline CPU. In this case the low-address
protection for that CPU will be dropped.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Fixes: 915fea04f9 ("s390/smp: enable DAT before CPU restart callback is called")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
This commit is contained in:
Alexander Gordeev 2022-07-20 07:24:03 +02:00
parent fc7fab3f91
commit 6f5c672d17
1 changed files with 1 additions and 1 deletions
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2
arch/s390/kernel/setup.c
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@ -508,8 +508,8 @@ static void __init setup_lowcore_dat_on(void)
S390_lowcore.svc_new_psw.mask |= PSW_MASK_DAT;
S390_lowcore.program_new_psw.mask |= PSW_MASK_DAT;
S390_lowcore.io_new_psw.mask |= PSW_MASK_DAT;
__ctl_store(S390_lowcore.cregs_save_area, 0, 15);
__ctl_set_bit(0, 28);
__ctl_store(S390_lowcore.cregs_save_area, 0, 15);
put_abs_lowcore(restart_flags, RESTART_FLAG_CTLREGS);
put_abs_lowcore(program_new_psw, lc->program_new_psw);
for (cr = 0; cr < ARRAY_SIZE(lc->cregs_save_area); cr++)