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From: Alexander Monakov <amonakov@ispras.ru>
To: Florian Weimer <fweimer@redhat.com>
Cc: Matheus Afonso Martins Moreira via Gcc <gcc@gcc.gnu.org>,
	 Matheus Afonso Martins Moreira <matheus.a.m.moreira@gmail.com>
Subject: Re: [RFC] Linux system call builtins
Date: Mon, 8 Apr 2024 16:01:47 +0300 (MSK)	[thread overview]
Message-ID: <754cbc8d-a1f0-d266-1052-21feda868004@ispras.ru> (raw)
In-Reply-To: <87h6gcvzsc.fsf@oldenburg.str.redhat.com>


On Mon, 8 Apr 2024, Florian Weimer wrote:

> * Alexander Monakov:
> 
> >> There is quite a bit of variance in how the kernel is entered.  On
> >> x86-64, one once popular mechanism is longer present in widely-used
> >> kernels.
> >
> > I assume you're implicitly referencing the vsyscall mechanism, but on
> > amd64 it's not useful to *enter the kernel*, right? It was useful for
> > obtaining the result of certain syscalls without actually entering
> > the kernel, like with vdso.
> 
> The implementation performed a standard system call if a pure userspace
> implementation wasn't possible.  It wasn't intended as a general-purpose
> way to enter the kernel (although it could be used as such, hence the
> desire to remove it in some cases).

I guess you meant it was "popular" only for the specific syscalls it 
provided acceleration for. I'm not sure how that is relevant to the
current discussion.

Alexander

  reply	other threads:[~2024-04-08 13:01 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-08  9:19 Matheus Afonso Martins Moreira
2024-04-08  9:58 ` Jonathan Wakely
2024-04-08 11:59   ` Matheus Afonso Martins Moreira
2024-04-08 14:00     ` Jonathan Wakely
2024-04-08 11:24 ` Florian Weimer
2024-04-08 11:44   ` Alexander Monakov
2024-04-08 11:50     ` Florian Weimer
2024-04-08 13:01       ` Alexander Monakov [this message]
2024-04-08 13:37   ` Matheus Afonso Martins Moreira
2024-04-08 18:18 ` Paul Iannetta
2024-04-08 18:26   ` Andrew Pinski
2024-04-08 20:01     ` Paul Iannetta
2024-04-08 20:20       ` Paul Koning
2024-04-10  1:48     ` Matheus Afonso Martins Moreira
2024-04-10 13:15       ` Paul Koning
2024-04-10 14:10         ` Matheus Afonso Martins Moreira
2024-04-10  1:26   ` Matheus Afonso Martins Moreira
2024-04-08 20:24 ` Paul Floyd
2024-04-10  2:19   ` Matheus Afonso Martins Moreira
2024-04-09 11:45 ` Szabolcs Nagy
2024-04-10  2:59   ` Matheus Afonso Martins Moreira
2024-04-10 11:04     ` Szabolcs Nagy
2024-04-10 14:00       ` Matheus Afonso Martins Moreira

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