From e5d961bff417ac8504d16ef9142d5e2da950724c Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 5 Sep 2023 15:49:37 +0200 Subject: [PATCH] s390/smp,mcck: fix early IPI handling [ Upstream commit 4a1725281fc5b0009944b1c0e1d2c1dc311a09ec ] Both the external call as well as the emergency signal submask bits in control register 0 are set before any interrupt handler is registered. Change the order and first register the interrupt handler and only then enable the interrupts by setting the corresponding bits in control register 0. This prevents that the second part of the machine check handler for early machine check handling is not executed: the machine check handler sends an IPI to the CPU it runs on. If the corresponding interrupts are enabled, but no interrupt handler is present, the interrupt is ignored. Reviewed-by: Sven Schnelle Acked-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Sasha Levin --- arch/s390/kernel/early.c | 12 +++--------- arch/s390/kernel/smp.c | 4 ++-- 2 files changed, 5 insertions(+), 11 deletions(-) diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c index 9693c8630e73..b3cb256ec669 100644 --- a/arch/s390/kernel/early.c +++ b/arch/s390/kernel/early.c @@ -237,15 +237,9 @@ static inline void save_vector_registers(void) #endif } -static inline void setup_control_registers(void) +static inline void setup_low_address_protection(void) { - unsigned long reg; - - __ctl_store(reg, 0, 0); - reg |= CR0_LOW_ADDRESS_PROTECTION; - reg |= CR0_EMERGENCY_SIGNAL_SUBMASK; - reg |= CR0_EXTERNAL_CALL_SUBMASK; - __ctl_load(reg, 0, 0); + __ctl_set_bit(0, 28); } static inline void setup_access_registers(void) @@ -304,7 +298,7 @@ void __init startup_init(void) save_vector_registers(); setup_topology(); sclp_early_detect(); - setup_control_registers(); + setup_low_address_protection(); setup_access_registers(); lockdep_on(); } diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 0031325ce4bc..436dbf4d743d 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -1007,12 +1007,12 @@ void __init smp_fill_possible_mask(void) void __init smp_prepare_cpus(unsigned int max_cpus) { - /* request the 0x1201 emergency signal external interrupt */ if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt)) panic("Couldn't request external interrupt 0x1201"); - /* request the 0x1202 external call external interrupt */ + ctl_set_bit(0, 14); if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt)) panic("Couldn't request external interrupt 0x1202"); + ctl_set_bit(0, 13); } void __init smp_prepare_boot_cpu(void)