Re: [PATCH 3.19 3/3] x86, mpx: Change the MPX enable/disable API to arch_prctl

From: Andy Lutomirski
Date: Tue Jan 06 2015 - 13:06:42 EST


On Tue, Jan 6, 2015 at 9:48 AM, Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> wrote:
> On 01/05/2015 09:59 PM, Andy Lutomirski wrote:
>> But I decided to check whether libmpx links against glibc, and I can't
>> find sources for it at all. Do they exist? Is there any code with
>> source available that invokes this prctl?
>>
>> If not, I personally have very little sympathy for the argument that a
>> binary buried in the depths of the Intel SDE would need to change if
>> we switched to using arch_prctl. And I think that it should issue the
>> syscall itself without using glibc, in which case the syscall wrapper
>> issue is moot.
>
> Andy, as I mentioned previously, there is code in a GCC branch that uses
> the existing prctl(). It's also been posted for review to one of the
> GCC mailing lists. I've been told that it will be in gcc 5.0.
>

Can you point me to it? I found the code generation stuff in the gcc
branch, but I couldn't find the runtime.

> The Intel SDE does not use the prctl() in any way that I know of.

I found a couple references suggesting that libmpx lived in the SDE.
For example:

https://software.intel.com/en-us/articles/using-intel-mpx-with-the-intel-software-development-emulator

--Andy

--
Andy Lutomirski
AMA Capital Management, LLC
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