Re: [PATCH] x86/entry: Improve system call entry comments
From: Andy Lutomirski
Date: Tue Mar 08 2016 - 13:45:52 EST
On Tue, Mar 8, 2016 at 10:40 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> On 03/08/16 02:30, Ingo Molnar wrote:
>>>>> + *
>>>>> + * This is considered a slow path. It is not used by modern libc
>>>>> + * implementations on modern hardware except during process startup.
>>>>> + *
>>> Sadly I believe Android still uses int $0x80 in the upstream version.
>> I don't see how that fact conflicts with my statement: on 64-bit kernels INT $0x80
>> will (of course) work, but will land on another entry point: entry_INT80_compat(),
>> not entry_INT80_32().
>> On 32-bit kernels the INT $0x80 entry point is entry_INT80_32().
> It doesn't. I was referring to the above quote. Trying to fix that.
I'm hoping that some day Bionic goes away and gets replaced by musl.
Of course, musl doesn't always use fast syscalls because it needs a
vdso facility that doesn't currently exist. I'll deal with that
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