Re: [PATCH] Add a text_poke syscall

From: H. Peter Anvin
Date: Wed Nov 20 2013 - 16:00:41 EST


On 11/20/2013 09:25 AM, Andi Kleen wrote:
> "H. Peter Anvin" <hpa@xxxxxxxxx> writes:
>>
>> We're talking user space here, which has different requirement (COW,
>> memory protection, ...) which means it is not really the same code. You
>> can't take a page fault while patching the kernel.
>
> The syscall pins the page, then it calls the kernel code.
> There are no page faults during patching.
>

But you don't need to pin anything if you just do it in userspace.
Again, it is particularly poignant for large batched operations.

-hpa

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