Re: [PATCH] x86: introduce push/pop macros which generate CFI_REL_OFFSET and CFI_RESTORE

[H. Peter Anvin]

On 01/12/2015 12:14 PM, Andy Lutomirski wrote:
> On Mon, Jan 12, 2015 at 12:11 PM, Borislav Petkov <bp@xxxxxxxxx> wrote:
>> On Mon, Jan 12, 2015 at 11:46:53AM -0800, Andy Lutomirski wrote:
>>> Dumb example:
>>>
>>>     pushq_cfi $__KERNEL_DS /* ss */
>>>
>>> This doesn't save anything that the unwinder would care about.
>>
>> And? The unwinder or whatever looks at that info simply ignores stuff it
>> is not interested in, no?
> 
> But CFI_REL_OFFSET $__KERNEL_DS, 0 probably isn't even well-formed and
> won't build.
> 

I think this is relatively easy to deal with at the expense of a large
.ifeq statement in the macro.

	-hpa


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