Re: [PATCH] x86: use enum instead of literals for trap values

From: Kees Cook
Date: Fri Mar 09 2012 - 13:54:21 EST


On Fri, Mar 9, 2012 at 10:28 AM, Borislav Petkov <bp@xxxxxxxxx> wrote:
> On Fri, Mar 09, 2012 at 10:21:52AM -0800, Kees Cook wrote:
>> > I have to admit personally to prefer something like X86_XCP_XX where XX
>> > is the two-letter code that the Intel documentation uses for that trap,
>> > i.e. #GP, #BR, #MC and so on.
>>
>> We need a single person to decide on this bike shed color. :) If the
>> list of enum names can be agreed on, I'll be happy to do the
>> search/replace for it.
>
> Well,
>
> here are my 2¢: I agree with hpa because
>
> a) it maps the CPU vendor documentation
> b) it is nicely short

How about:

X86_XCP_DE = 0, /* 0, Divide-by-zero */
X86_XCP_DB, /* 1, Debug */
X86_XCP_NMI, /* 2, Non-maskable Interrupt */
X86_XCP_BP, /* 3, Breakpoint */
X86_XCP_OF, /* 4, Overflow */
X86_XCP_BR, /* 5, Bound Range Exceeded */
X86_XCP_UD, /* 6, Invalid Opcode */
X86_XCP_NM, /* 7, Device Not Available */
X86_XCP_DF, /* 8, Double Fault */
X86_XCP_OLD_MF, /* 9, Coprocessor Segment Overrun */
X86_XCP_TS, /* 10, Invalid TSS */
X86_XCP_NP, /* 11, Segment Not Present */
X86_XCP_SS, /* 12, Stack-Segment Fault */
X86_XCP_GP, /* 13, General Protection Fault */
X86_XCP_PF, /* 14, Page Fault */
X86_XCP_RES, /* 15, Reserved */
X86_XCP_MF, /* 16, x87 Floating-Point Exception */
X86_XCP_AC, /* 17, Alignment Check */
X86_XCP_MC, /* 18, Machine Check */
X86_XCP_XM, /* 19, SIMD Floating-Point Exception */
X86_XCP_IRET = 32, /* 32, IRET Exception */

There is a name collision for "MF", there's no mnemonic for NMI, IRET,
or the reserved "spurious" interrupt.

Can use "VEC" instead "XCP", as Steven suggests. FWIW, the table in
the Intel manual I had handy says "Exceptions/Interrupts".

-Kees

--
Kees Cook
ChromeOS Security
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