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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2010-11-10 10:05:57 +0100
committerMartin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com>2010-11-10 10:05:54 +0100
commitadb45839817392102e659c19e5c19aa39530021f (patch)
tree00a28ba170a4f82e083942863997a55e5389b30a /arch/s390/kernel
parentbecf91f18750cf1c60828aa2ee63a36b05c2e4d0 (diff)
downloadlinux-linaro-android-adb45839817392102e659c19e5c19aa39530021f.tar.gz
[S390] kprobes: disable interrupts throughout
Execute the kprobe exception and fault handler with interrupts disabled. To disable the interrupts only while a single step is in progress is not good enough, a kprobe from interrupt context while another kprobe is handled can confuse the internal house keeping. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel')
-rw-r--r--arch/s390/kernel/kprobes.c41
1 files changed, 27 insertions, 14 deletions
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index d60fc439851..70cf73bdba2 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -30,6 +30,7 @@
#include <asm/sections.h>
#include <linux/module.h>
#include <linux/slab.h>
+#include <linux/hardirq.h>
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
@@ -212,7 +213,7 @@ static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
/* Set the PER control regs, turns on single step for this address */
__ctl_load(kprobe_per_regs, 9, 11);
regs->psw.mask |= PSW_MASK_PER;
- regs->psw.mask &= ~(PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK);
+ regs->psw.mask &= ~(PSW_MASK_IO | PSW_MASK_EXT);
}
static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
@@ -239,7 +240,7 @@ static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
__get_cpu_var(current_kprobe) = p;
/* Save the interrupt and per flags */
kcb->kprobe_saved_imask = regs->psw.mask &
- (PSW_MASK_PER | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK);
+ (PSW_MASK_PER | PSW_MASK_IO | PSW_MASK_EXT);
/* Save the control regs that govern PER */
__ctl_store(kcb->kprobe_saved_ctl, 9, 11);
}
@@ -316,8 +317,6 @@ 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;
@@ -465,8 +464,6 @@ 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();
@@ -482,7 +479,7 @@ out:
return 1;
}
-int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+static int __kprobes kprobe_trap_handler(struct pt_regs *regs, int trapnr)
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
@@ -508,8 +505,6 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
restore_previous_kprobe(kcb);
else {
reset_current_kprobe();
- if (regs->psw.mask & (PSW_MASK_PER | PSW_MASK_IO))
- local_irq_enable();
}
preempt_enable_no_resched();
break;
@@ -553,6 +548,18 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
return 0;
}
+int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+{
+ int ret;
+
+ if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT))
+ local_irq_disable();
+ ret = kprobe_trap_handler(regs, trapnr);
+ if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT))
+ local_irq_restore(regs->psw.mask & ~PSW_MASK_PER);
+ return ret;
+}
+
/*
* Wrapper routine to for handling exceptions.
*/
@@ -560,8 +567,12 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data)
{
struct die_args *args = (struct die_args *)data;
+ struct pt_regs *regs = args->regs;
int ret = NOTIFY_DONE;
+ if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT))
+ local_irq_disable();
+
switch (val) {
case DIE_BPT:
if (kprobe_handler(args->regs))
@@ -572,16 +583,17 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
ret = NOTIFY_STOP;
break;
case DIE_TRAP:
- /* kprobe_running() needs smp_processor_id() */
- preempt_disable();
- if (kprobe_running() &&
- kprobe_fault_handler(args->regs, args->trapnr))
+ if (!preemptible() && kprobe_running() &&
+ kprobe_trap_handler(args->regs, args->trapnr))
ret = NOTIFY_STOP;
- preempt_enable();
break;
default:
break;
}
+
+ if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT))
+ local_irq_restore(regs->psw.mask & ~PSW_MASK_PER);
+
return ret;
}
@@ -595,6 +607,7 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
/* setup return addr to the jprobe handler routine */
regs->psw.addr = (unsigned long)(jp->entry) | PSW_ADDR_AMODE;
+ regs->psw.mask &= ~(PSW_MASK_IO | PSW_MASK_EXT);
/* r14 is the function return address */
kcb->jprobe_saved_r14 = (unsigned long)regs->gprs[14];