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Commit c416ddf5 authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
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x86: Unspaghettize do_trap() 



Cleanup the label maze in this function. Having a
seperate function to first handle the traps that don't
generate a signal makes it easier to convert into
more readable conditional paths.

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1348577479-2564-1-git-send-email-fweisbec@gmail.com


[ Fixed 32-bit build failure. ]
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 1b2b23d8

arch/x86/kernel/traps.c

+29 −31
Original line number Diff line number Diff line
@@ -107,30 +107,45 @@ static inline void preempt_conditional_cli(struct pt_regs *regs) 
	dec_preempt_count();

}



static void __kprobes

do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,

	long error_code, siginfo_t *info)

static int __kprobes

do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str,

		  struct pt_regs *regs,	long error_code)

{

	struct task_struct *tsk = current;



#ifdef CONFIG_X86_32

	if (regs->flags & X86_VM_MASK) {

		/*

		 * traps 0, 1, 3, 4, and 5 should be forwarded to vm86.

		 * Traps 0, 1, 3, 4, and 5 should be forwarded to vm86.

		 * On nmi (interrupt 2), do_trap should not be called.

		 */

		if (trapnr < X86_TRAP_UD)

			goto vm86_trap;

		goto trap_signal;

		if (trapnr < X86_TRAP_UD) {

			if (!handle_vm86_trap((struct kernel_vm86_regs *) regs,

						error_code, trapnr))

				return 0;

		}

		return -1;

	}

#endif

	if (!user_mode(regs)) {

		if (!fixup_exception(regs)) {

			tsk->thread.error_code = error_code;

			tsk->thread.trap_nr = trapnr;

			die(str, regs, error_code);

		}

		return 0;

	}



	if (!user_mode(regs))

		goto kernel_trap;

	return -1;

}



#ifdef CONFIG_X86_32

trap_signal:

#endif

static void __kprobes

do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,

	long error_code, siginfo_t *info)

{

	struct task_struct *tsk = current;





	if (!do_trap_no_signal(tsk, trapnr, str, regs, error_code))

		return;

	/*

	 * We want error_code and trap_nr set for userspace faults and

	 * kernelspace faults which result in die(), but not
@@ -158,23 +173,6 @@ trap_signal: 
		force_sig_info(signr, info, tsk);

	else

		force_sig(signr, tsk);

	return;



kernel_trap:

	if (!fixup_exception(regs)) {

		tsk->thread.error_code = error_code;

		tsk->thread.trap_nr = trapnr;

		die(str, regs, error_code);

	}

	return;



#ifdef CONFIG_X86_32

vm86_trap:

	if (handle_vm86_trap((struct kernel_vm86_regs *) regs,

						error_code, trapnr))

		goto trap_signal;

	return;

#endif

}



#define DO_ERROR(trapnr, signr, str, name)				\