Messages in this thread | | | Date | Fri, 9 Mar 2012 10:28:45 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86: use enum instead of literals for trap values |
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* Kees Cook <keescook@chromium.org> wrote:
> The traps are referred to by their numbers and it can be difficult to > understand them while reading the code without context. This patch adds > enumeration of the trap numbers and replaces the numbers with the correct > enum for x86. > > Signed-off-by: Kees Cook <keescook@chromium.org> > > --- > I've updated Aditya Kali's earlier patch: > https://lkml.org/lkml/2011/4/22/328 > --- > arch/x86/include/asm/traps.h | 25 +++++++++ > arch/x86/kernel/irqinit.c | 2 +- > arch/x86/kernel/traps.c | 117 ++++++++++++++++++++++-------------------- > 3 files changed, 88 insertions(+), 56 deletions(-) > > diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h > index 0012d09..768afb2 100644 > --- a/arch/x86/include/asm/traps.h > +++ b/arch/x86/include/asm/traps.h > @@ -89,4 +89,29 @@ asmlinkage void smp_thermal_interrupt(void); > asmlinkage void mce_threshold_interrupt(void); > #endif > > +/* Interrupts/Exceptions */ > +enum { > + INTR_DIV_BY_ZERO = 0, /* 0 */ > + INTR_DEBUG, /* 1 */ > + INTR_NMI, /* 2 */ > + INTR_BREAKPOINT, /* 3 */ > + INTR_OVERFLOW, /* 4 */ > + INTR_BOUNDS_CHECK, /* 5 */ > + INTR_INVALID_OP, /* 6 */ > + INTR_NO_DEV, /* 7 */ > + INTR_DBL_FAULT, /* 8 */ > + INTR_SEG_OVERRUN, /* 9 */ > + INTR_INVALID_TSS, /* 10 */ > + INTR_NO_SEG, /* 11 */ > + INTR_STACK_FAULT, /* 12 */ > + INTR_GPF, /* 13 */ > + INTR_PAGE_FAULT, /* 14 */ > + INTR_SPURIOUS, /* 15 */ > + INTR_COPROCESSOR, /* 16 */ > + INTR_ALIGNMENT, /* 17 */ > + INTR_MCE, /* 18 */ > + INTR_SIMD_COPROCESSOR, /* 19 */ > + INTR_IRET = 32, /* 32 */ > +};
> @@ -453,14 +458,15 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) > /* > * Note that we play around with the 'TS' bit in an attempt to get > * the correct behaviour even in the presence of the asynchronous > - * IRQ13 behaviour > + * INTR_GPF behaviour > */
> @@ -529,8 +535,9 @@ void math_error(struct pt_regs *regs, int error_code, int trapnr) > info.si_code = FPE_FLTRES; > } else { > /* > - * If we're using IRQ 13, or supposedly even some trap 16 > - * implementations, it's possible we get a spurious trap... > + * If we're using INTR_GPF, or supposedly even some trap > + * INTR_COPROCESSOR implementations, it's possible we get a > + * spurious trap...
There's confusion in this patch between legacy IRQ #13 [vector 0x20 + 13 ] and #GPF general protection fault [vector 13] - they are not the same.
Furthermore, the INTR_ naming is not ideal either for (most of) these entries: for example we don't think of a page fault as an asynchronous interrupt entity - we think of it as a more or less synchronous fault/exception.
Thus a X86_*_FAULT_VEC naming pattern might be better:
X86_PAGE_FAULT_VEC X86_DOUBLE_FAULT_VEC
(With X86_*_EXCEPTION_VEC applied where appropriate.)
I don't disagree with the general principle of the cleanup otherwise, the numeric literals are often ambiguous and confusing - as the trap 13 - irq 13 mixup above shows.
Thanks,
Ingo
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