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From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: linux-kernel@vger.kernel.org, 0x7f454c46@gmail.com,
	Adam Borowski <kilobyte@angband.pl>,
	linux-mm@kvack.org, Andrei Vagin <avagin@gmail.com>,
	Borislav Petkov <bp@suse.de>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCHv2] x86/mm: set x32 syscall bit in SET_PERSONALITY()
Date: Tue, 21 Mar 2017 20:17:23 +0300	[thread overview]
Message-ID: <20170321171723.GB21564@uranus.lan> (raw)
In-Reply-To: <20170321163712.20334-1-dsafonov@virtuozzo.com>

On Tue, Mar 21, 2017 at 07:37:12PM +0300, Dmitry Safonov wrote:
...
> diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
> index d6b784a5520d..d3d4d9abcaf8 100644
> --- a/arch/x86/kernel/process_64.c
> +++ b/arch/x86/kernel/process_64.c
> @@ -519,8 +519,14 @@ void set_personality_ia32(bool x32)
>  		if (current->mm)
>  			current->mm->context.ia32_compat = TIF_X32;
>  		current->personality &= ~READ_IMPLIES_EXEC;
> -		/* in_compat_syscall() uses the presence of the x32
> -		   syscall bit flag to determine compat status */
> +		/*
> +		 * in_compat_syscall() uses the presence of the x32
> +		 * syscall bit flag to determine compat status.
> +		 * On the bitness of syscall relies x86 mmap() code,
> +		 * so set x32 syscall bit right here to make
> +		 * in_compat_syscall() work during exec().
> +		 */
> +		task_pt_regs(current)->orig_ax |= __X32_SYSCALL_BIT;
>  		current->thread.status &= ~TS_COMPAT;

Hi! I must admit I didn't follow close the overall series (so can't
comment much here :) but I have a slightly unrelated question -- is
there a way to figure out if task is running in x32 mode say with
some ptrace or procfs sign?

WARNING: multiple messages have this Message-ID (diff)
From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: linux-kernel@vger.kernel.org, 0x7f454c46@gmail.com,
	Adam Borowski <kilobyte@angband.pl>,
	linux-mm@kvack.org, Andrei Vagin <avagin@gmail.com>,
	Borislav Petkov <bp@suse.de>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCHv2] x86/mm: set x32 syscall bit in SET_PERSONALITY()
Date: Tue, 21 Mar 2017 20:17:23 +0300	[thread overview]
Message-ID: <20170321171723.GB21564@uranus.lan> (raw)
In-Reply-To: <20170321163712.20334-1-dsafonov@virtuozzo.com>

On Tue, Mar 21, 2017 at 07:37:12PM +0300, Dmitry Safonov wrote:
...
> diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
> index d6b784a5520d..d3d4d9abcaf8 100644
> --- a/arch/x86/kernel/process_64.c
> +++ b/arch/x86/kernel/process_64.c
> @@ -519,8 +519,14 @@ void set_personality_ia32(bool x32)
>  		if (current->mm)
>  			current->mm->context.ia32_compat = TIF_X32;
>  		current->personality &= ~READ_IMPLIES_EXEC;
> -		/* in_compat_syscall() uses the presence of the x32
> -		   syscall bit flag to determine compat status */
> +		/*
> +		 * in_compat_syscall() uses the presence of the x32
> +		 * syscall bit flag to determine compat status.
> +		 * On the bitness of syscall relies x86 mmap() code,
> +		 * so set x32 syscall bit right here to make
> +		 * in_compat_syscall() work during exec().
> +		 */
> +		task_pt_regs(current)->orig_ax |= __X32_SYSCALL_BIT;
>  		current->thread.status &= ~TS_COMPAT;

Hi! I must admit I didn't follow close the overall series (so can't
comment much here :) but I have a slightly unrelated question -- is
there a way to figure out if task is running in x32 mode say with
some ptrace or procfs sign?

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  reply	other threads:[~2017-03-21 17:17 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-21 16:37 [PATCHv2] x86/mm: set x32 syscall bit in SET_PERSONALITY() Dmitry Safonov
2017-03-21 16:37 ` Dmitry Safonov
2017-03-21 17:17 ` Cyrill Gorcunov [this message]
2017-03-21 17:17   ` Cyrill Gorcunov
2017-03-21 17:45   ` Andy Lutomirski
2017-03-21 17:45     ` Andy Lutomirski
2017-03-21 18:05     ` [Q] Figuring out task mode Cyrill Gorcunov
2017-03-21 18:05       ` Cyrill Gorcunov
2017-03-21 23:54       ` Andy Lutomirski
2017-03-21 23:54         ` Andy Lutomirski
2017-03-21 18:09     ` [PATCHv2] x86/mm: set x32 syscall bit in SET_PERSONALITY() Dmitry Safonov
2017-03-21 18:09       ` Dmitry Safonov
2017-03-21 18:40       ` Cyrill Gorcunov
2017-03-21 18:40         ` Cyrill Gorcunov
2017-03-21 18:51         ` hpa
2017-03-21 18:51           ` hpa
2017-03-21 19:07           ` Cyrill Gorcunov
2017-03-21 19:07             ` Cyrill Gorcunov
2017-03-21 19:20             ` hpa
2017-03-21 19:20               ` hpa
2017-03-21 19:19         ` Dmitry Safonov
2017-03-21 19:19           ` Dmitry Safonov
2017-03-21 19:24           ` Cyrill Gorcunov
2017-03-21 19:24             ` Cyrill Gorcunov
2017-03-21 19:34             ` Dmitry Safonov
2017-03-21 19:34               ` Dmitry Safonov
2017-03-21 19:31       ` Andy Lutomirski
2017-03-21 19:31         ` Andy Lutomirski
2017-03-21 19:34         ` Cyrill Gorcunov
2017-03-21 19:34           ` Cyrill Gorcunov
2017-03-21 19:42         ` Dmitry Safonov
2017-03-21 19:42           ` Dmitry Safonov
2017-03-21 20:04           ` Dmitry Safonov
2017-03-21 20:04             ` Dmitry Safonov
2017-03-21 18:49     ` hpa
2017-03-21 18:49       ` hpa
2017-03-21 17:27 ` hpa
2017-03-21 17:27   ` hpa
2017-03-21 17:27   ` Dmitry Safonov
2017-03-21 17:27     ` Dmitry Safonov

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