5.15-stable review patch. If anyone has any objections, please let me know.
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From: Heiko Carstens hca@linux.ibm.com
[ 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 svens@linux.ibm.com Acked-by: Alexander Gordeev agordeev@linux.ibm.com Signed-off-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Vasily Gorbik gor@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 9857cb0467268..9898582f44da8 100644 --- a/arch/s390/kernel/early.c +++ b/arch/s390/kernel/early.c @@ -250,15 +250,9 @@ 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) @@ -311,7 +305,7 @@ 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 35af70ed58fc7..48f67a69d119b 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -1003,12 +1003,12 @@ 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)