Re: [PATCH 1/2] x86: entry_64.S: always allocate complete "struct pt_regs"

From: Andy Lutomirski
Date: Thu Feb 12 2015 - 17:30:24 EST


On Thu, Feb 12, 2015 at 1:53 PM, Denys Vlasenko
<vda.linux@xxxxxxxxxxxxxx> wrote:
> On Thu, Feb 12, 2015 at 6:17 PM, Borislav Petkov <bp@xxxxxxxxx> wrote:
>> On Wed, Feb 11, 2015 at 10:55:52PM +0100, Denys Vlasenko wrote:
>>> Macros which manipulate "struct pt_regs" on stack are reworked:
>>> ALLOC_PT_GPREGS_ON_STACK allocates the structure.
>>> SAVE_C_REGS saves to it those registers which are clobbered by C code.
>>> SAVE_EXTRA_REGS saves to it all other registers.
>>> Corresponding RESTORE_* and REMOVE_PT_GPREGS_FROM_STACK macros reverse it.
>>>
>>
>> You'd need to redo that patch against latest upstream because of changes
>> it is missing:
>>
>> Andy's branch x86/entry should have them too:
>> http://git.kernel.org/cgit/linux/kernel/git/luto/linux.git
>>
>> arch/x86/kernel/entry_64.S: Assembler messages:
>> arch/x86/kernel/entry_64.S:760: Error: no such instruction: `restore_args 1,8,1'
>> make[2]: *** [arch/x86/kernel/entry_64.o] Error 1
>> make[1]: *** [arch/x86/kernel] Error 2
>> make[1]: *** Waiting for unfinished jobs....
>> make: *** [arch/x86] Error 2
>> make: *** Waiting for unfinished jobs....
>
> Thanks!
> The renaming of macros caught the bug at compile time, as intended.
>
> I'll send an updated patch set v3 in a minute. It will have
> additional patch in front, since that location in code
> also wrongly uses R11 instead of ARGOFFSET.

If you aren't already, can you base it here:

https://git.kernel.org/cgit/linux/kernel/git/luto/linux.git/log/?h=x86/entry

--Andy

--
Andy Lutomirski
AMA Capital Management, LLC
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