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From: Richard Weinberger <richard@nod.at>
To: Benjamin Berg <benjamin@sipsolutions.net>
Cc: Richard Weinberger <richard.weinberger@gmail.com>,
	 linux-um <linux-um@lists.infradead.org>
Subject: Re: [PATCH v3 09/11] um: Rely on PTRACE_SETREGSET to set FS/GS base registers
Date: Fri, 5 Jan 2024 14:29:55 +0100 (CET)	[thread overview]
Message-ID: <965367427.201125.1704461395241.JavaMail.zimbra@nod.at> (raw)
In-Reply-To: <9ec2eafe0ea44e3bce1e5fa96c4a9488c3d43a8c.camel@sipsolutions.net>

----- Ursprüngliche Mail -----
> Von: "Benjamin Berg" <benjamin@sipsolutions.net>
> On Fri, 2024-01-05 at 00:05 +0100, Richard Weinberger wrote:
>> On Fri, Nov 10, 2023 at 12:03 PM <benjamin@sipsolutions.net> wrote:
>> > 
>> > From: Benjamin Berg <benjamin@sipsolutions.net>
>> > 
>> > These registers are saved/restored together with the other general
>> > registers using ptrace. In arch_set_tls we then just need to set
>> > the
>> > register and it will be synced back normally.
>> > 
>> > Most of this logic was introduced in commit f355559cf7845 ("[PATCH]
>> > uml:
>> > x86_64 thread fixes"). However, at least today we can rely on
>> > ptrace to
>> 
>> Do you know since when exactly? I don't want to break UML in subtle ways
>> on old kernels.
> 
> To be honest, I don't remember, and I doubt I really understood what I
> was doing.
> 
> Anyway, I now found this commit now, which is contained in v2.6.25:

Okay, 2.6.26 is way older than anything supported. So I'll apply our patch. :-)

Thanks,
//richard


  reply	other threads:[~2024-01-05 13:30 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-10 11:03 [PATCH v3 00/11] General cleanups and fixes from SECCOMP patchset benjamin
2023-11-10 11:03 ` [PATCH v3 01/11] um: Drop support for hosts without SYSEMU_SINGLESTEP support benjamin
2023-11-10 11:03 ` [PATCH v3 02/11] um: Drop NULL check from start_userspace benjamin
2023-11-10 11:03 ` [PATCH v3 03/11] um: Make errors to stop ptraced child fatal during startup benjamin
2023-11-10 11:03 ` [PATCH v3 04/11] um: Don't use vfprintf() for os_info() benjamin
2024-01-04 22:37   ` Richard Weinberger
2024-01-05  8:12     ` Benjamin Berg
2024-01-05  8:56       ` Johannes Berg
2024-01-05  9:16         ` Richard Weinberger
2023-11-10 11:03 ` [PATCH v3 05/11] um: Do not use printk in SIGWINCH helper thread benjamin
2023-11-10 11:03 ` [PATCH v3 06/11] um: Reap winch thread if it fails benjamin
2023-11-10 11:03 ` [PATCH v3 07/11] um: Do not use printk in userspace trampoline benjamin
2023-11-10 11:03 ` [PATCH v3 08/11] um: Always inline stub functions benjamin
2023-11-10 11:03 ` [PATCH v3 09/11] um: Rely on PTRACE_SETREGSET to set FS/GS base registers benjamin
2024-01-04 23:05   ` Richard Weinberger
2024-01-04 23:34     ` Richard Weinberger
2024-01-05  9:54     ` Benjamin Berg
2024-01-05 13:29       ` Richard Weinberger [this message]
2023-11-10 11:03 ` [PATCH v3 10/11] um: Remove unused register save/restore functions benjamin
2023-11-10 11:03 ` [PATCH v3 11/11] um: Mark 32bit syscall helpers as clobbering memory benjamin

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