From 12dd19c159659ec9050f45dc8a2ff3c3917f4be3 Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Sat, 13 Aug 2022 19:45:21 +0200 Subject: s390/boot: fix absolute zero lowcore corruption on boot Crash dump always starts on CPU0. In case CPU0 is offline the prefix page is not installed and the absolute zero lowcore is used. However, struct lowcore::mcesad is never assigned and stays zero. That leads to __machine_kdump() -> save_vx_regs() call silently stores vector registers to the absolute lowcore at 0x11b0 offset. Fixes: a62bc0739253 ("s390/kdump: add support for vector extension") Reviewed-by: Heiko Carstens Signed-off-by: Alexander Gordeev Signed-off-by: Vasily Gorbik --- arch/s390/kernel/nmi.c | 2 +- arch/s390/kernel/setup.c | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c index 60ac66aab163..31cb9b00a36b 100644 --- a/arch/s390/kernel/nmi.c +++ b/arch/s390/kernel/nmi.c @@ -64,7 +64,7 @@ static inline unsigned long nmi_get_mcesa_size(void) * structure. The structure is required for machine check happening * early in the boot process. */ -static struct mcesa boot_mcesa __initdata __aligned(MCESA_MAX_SIZE); +static struct mcesa boot_mcesa __aligned(MCESA_MAX_SIZE); void __init nmi_alloc_mcesa_early(u64 *mcesad) { diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index ed4fbbbdd1b0..74adb433c257 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -479,6 +479,7 @@ static void __init setup_lowcore_dat_off(void) put_abs_lowcore(restart_data, lc->restart_data); put_abs_lowcore(restart_source, lc->restart_source); put_abs_lowcore(restart_psw, lc->restart_psw); + put_abs_lowcore(mcesad, lc->mcesad); mcck_stack = (unsigned long)memblock_alloc(THREAD_SIZE, THREAD_SIZE); if (!mcck_stack) -- cgit v1.2.3 From 8d96bba75a43ba564bf8732e955d9f519d2bbaec Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Wed, 20 Jul 2022 07:24:03 +0200 Subject: s390/smp: enforce lowcore protection on CPU restart As result of commit 915fea04f932 ("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 Fixes: 915fea04f932 ("s390/smp: enable DAT before CPU restart callback is called") Signed-off-by: Alexander Gordeev Signed-off-by: Vasily Gorbik --- arch/s390/kernel/setup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index 74adb433c257..bbd4bde4f65d 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -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++) -- cgit v1.2.3