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x86/traps: Split int3 handler up

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For code simplicity split up the int3 handler into a kernel and user part
which makes the code flow simpler to understand.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505135314.045220765@linutronix.de
This commit is contained in:
Peter Zijlstra 2020-03-05 16:09:52 +01:00 committed by Thomas Gleixner
parent 8edd7e37ae
commit 21e28290b3
1 changed files with 40 additions and 28 deletions
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68
arch/x86/kernel/traps.c
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@ -568,6 +568,35 @@ DEFINE_IDTENTRY_ERRORCODE(exc_general_protection)
cond_local_irq_disable(regs);
}
static bool do_int3(struct pt_regs *regs)
{
int res;
#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
if (kgdb_ll_trap(DIE_INT3, "int3", regs, 0, X86_TRAP_BP,
SIGTRAP) == NOTIFY_STOP)
return true;
#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
#ifdef CONFIG_KPROBES
if (kprobe_int3_handler(regs))
return true;
#endif
res = notify_die(DIE_INT3, "int3", regs, 0, X86_TRAP_BP, SIGTRAP);
return res == NOTIFY_STOP;
}
static void do_int3_user(struct pt_regs *regs)
{
if (do_int3(regs))
return;
cond_local_irq_enable(regs);
do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, 0, 0, NULL);
cond_local_irq_disable(regs);
}
DEFINE_IDTENTRY_RAW(exc_int3)
{
/*
@ -585,37 +614,20 @@ DEFINE_IDTENTRY_RAW(exc_int3)
* because the INT3 could have been hit in any context including
* NMI.
*/
if (user_mode(regs))
if (user_mode(regs)) {
idtentry_enter(regs);
else
nmi_enter();
instrumentation_begin();
#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
if (kgdb_ll_trap(DIE_INT3, "int3", regs, 0, X86_TRAP_BP,
SIGTRAP) == NOTIFY_STOP)
goto exit;
#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
#ifdef CONFIG_KPROBES
if (kprobe_int3_handler(regs))
goto exit;
#endif
if (notify_die(DIE_INT3, "int3", regs, 0, X86_TRAP_BP,
SIGTRAP) == NOTIFY_STOP)
goto exit;
cond_local_irq_enable(regs);
do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, 0, 0, NULL);
cond_local_irq_disable(regs);
exit:
instrumentation_end();
if (user_mode(regs))
instrumentation_begin();
do_int3_user(regs);
instrumentation_end();
idtentry_exit(regs);
else
} else {
nmi_enter();
instrumentation_begin();
if (!do_int3(regs))
die("int3", regs, 0);
instrumentation_end();
nmi_exit();
}
}
#ifdef CONFIG_X86_64