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| author | Alexander Gordeev <agordeev@linux.ibm.com> | 2022-12-17 11:01:16 +0100 |
|---|---|---|
| committer | Heiko Carstens <hca@linux.ibm.com> | 2023-02-28 13:19:05 +0100 |
| commit | e7ec1d2eac9cad57ff615ef6cc3e324ab7238b82 (patch) | |
| tree | 1e17b6a1b74d4bb6aef6b4f5b3821115f4f98d57 /arch/s390/kernel/entry.S | |
| parent | 5e02c74905cb00184b6c5ae70b1c1bfae5b3bd17 (diff) | |
s390/mcck: cleanup user process termination path
If a machine check interrupt hits while user process is
running __s390_handle_mcck() helper function is called
directly from the interrupt handler and terminates the
current process by calling make_task_dead() routine.
The make_task_dead() is not allowed to be called from
interrupt context which forces the machine check handler
switch to the kernel stack and enable local interrupts
first.
The __s390_handle_mcck() could also be called to service
pending work, but this time from the external interrupts
handler. It is the machine check handler that establishes
the work and schedules the external interrupt, therefore
the machine check interrupt itself should be disabled
while reading out the corresponding variable:
local_mcck_disable();
mcck = *this_cpu_ptr(&cpu_mcck);
memset(this_cpu_ptr(&cpu_mcck), 0, sizeof(mcck));
local_mcck_enable();
However, local_mcck_disable() does not have effect when
__s390_handle_mcck() is called directly form the machine
check handler, since the machine check interrupt is still
disabled. Therefore, it is not the opening bracket to the
following local_mcck_enable() function.
Simplify the user process termination flow by scheduling
the external interrupt and killing the affected process
from the interrupt context.
Assume a kernel-generated signal is always delivered and
ignore a value returned by do_send_sig_info() funciton.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'arch/s390/kernel/entry.S')
| -rw-r--r-- | arch/s390/kernel/entry.S | 10 |
1 files changed, 0 insertions, 10 deletions
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index c8d8c9960936..76a06f3d3671 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -562,16 +562,6 @@ ENTRY(mcck_int_handler) xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) lgr %r2,%r11 # pass pointer to pt_regs brasl %r14,s390_do_machine_check - cghi %r2,0 - je .Lmcck_return - lg %r1,__LC_KERNEL_STACK # switch to kernel stack - mvc STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11) - xc __SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1) - la %r11,STACK_FRAME_OVERHEAD(%r1) - lgr %r2,%r11 - lgr %r15,%r1 - brasl %r14,s390_handle_mcck -.Lmcck_return: lctlg %c1,%c1,__PT_CR1(%r11) lmg %r0,%r10,__PT_R0(%r11) mvc __LC_RETURN_MCCK_PSW(16),__PT_PSW(%r11) # move return PSW |