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[S390] fix kprobes single stepping

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Fix kprobes after git commit 1e54622e04
broke it. The kprobe_handler is now called with interrupts in the state
at the time of the breakpoint. The single step of the replaced instruction
is done with interrupts off which makes it necessary to enable and disable
the interupts in the kprobes code.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2010-10-29 16:50:45 +02:00 committed by Martin Schwidefsky
parent f2166bb117
commit 9ec2708053
3 changed files with 10 additions and 1 deletions
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1
arch/s390/kernel/entry.S
View File

@ -557,6 +557,7 @@ pgm_svcper:
# per was called from kernel, must be kprobes
#
kernel_per:
REENABLE_IRQS
mvi SP_SVCNR(%r15),0xff # set trap indication to pgm check
mvi SP_SVCNR+1(%r15),0xff
la %r2,SP_PTREGS(%r15) # address of register-save area

1
arch/s390/kernel/entry64.S
View File

@ -568,6 +568,7 @@ pgm_svcper:
# per was called from kernel, must be kprobes
#
kernel_per:
REENABLE_IRQS
xc SP_SVCNR(2,%r15),SP_SVCNR(%r15) # clear svc number
la %r2,SP_PTREGS(%r15) # address of register-save area
brasl %r14,do_single_step

9
arch/s390/kernel/kprobes.c
View File

@ -316,6 +316,8 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
return 1;
ss_probe:
if (regs->psw.mask & (PSW_MASK_PER | PSW_MASK_IO))
local_irq_disable();
prepare_singlestep(p, regs);
kcb->kprobe_status = KPROBE_HIT_SS;
return 1;
@ -463,6 +465,8 @@ static int __kprobes post_kprobe_handler(struct pt_regs *regs)
goto out;
}
reset_current_kprobe();
if (regs->psw.mask & (PSW_MASK_PER | PSW_MASK_IO))
local_irq_enable();
out:
preempt_enable_no_resched();
@ -502,8 +506,11 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
regs->psw.mask |= kcb->kprobe_saved_imask;
if (kcb->kprobe_status == KPROBE_REENTER)
restore_previous_kprobe(kcb);
else
else {
reset_current_kprobe();
if (regs->psw.mask & (PSW_MASK_PER | PSW_MASK_IO))
local_irq_enable();
}
preempt_enable_no_resched();
break;
case KPROBE_HIT_ACTIVE: