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SubjectRe: [cleanup] do_general_protection doesn't disable irq
Andrea Arcangeli wrote:
> A trap gate shouldn't affect the irq status at all.
>
> This should be a valid cleanup that removes a slightly confusing noop:
>
> Index: linux-2.5/arch/i386/kernel/traps.c
> ===================================================================
> RCS file: /home/andrea/crypto/cvs/linux-2.5/arch/i386/kernel/traps.c,v
> retrieving revision 1.77
> diff -u -p -r1.77 traps.c
> --- linux-2.5/arch/i386/kernel/traps.c 13 Jul 2004 18:02:33 -0000 1.77
> +++ linux-2.5/arch/i386/kernel/traps.c 30 Jul 2004 02:44:23 -0000
> @@ -431,9 +431,6 @@ DO_ERROR_INFO(17, SIGBUS, "alignment che
>
> asmlinkage void do_general_protection(struct pt_regs * regs, long error_code)
> {
> - if (regs->eflags & X86_EFLAGS_IF)
> - local_irq_enable();
> -
> if (regs->eflags & VM_MASK)
> goto gp_in_vm86;
>
>
> Thanks to Karsten for noticing a trap gate doesn't actually enable irq
> by default either (offtopic issue with the above patch, but while
> reading the 2.6 code I found the above bit which just confused me more
> since it's a noop, either that or you meant to use set_intr_gate, not
> set_trap_gate on the do_general_protection handler, but it seems not
> needed to use a trap gate since a trap gate shouldn't enable irqs by
> default). Please correct me if wrong.

This is there for vm86 mode. See http://tinyurl.com/3m5nr

--
Brian Gerst
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