From: nico@fluxnic.net (Nicolas Pitre)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 2/2] ARM: memory: define TASK_UNMAPPED_BASE in terms of TASK_SIZE
Date: Thu, 31 Jan 2013 10:58:32 -0500 (EST) [thread overview]
Message-ID: <alpine.LFD.2.02.1301311058070.6300@xanadu.home> (raw)
In-Reply-To: <1359644949-18550-2-git-send-email-will.deacon@arm.com>
On Thu, 31 Jan 2013, Will Deacon wrote:
> TASK_UNMAPPED_BASE is defined directly in terms of PAGE_OFFSET, which is
> confusing given that the modules area sits between here and TASK_SIZE
> and is not available for user allocations.
>
> This patch defines TASK_UNMAPPED_BASE in terms of TASK_SIZE instead and
> fixes a bug introduced by 394ef6403abc ("mm: use vm_unmapped_area() on
> arm architecture") whereby TASK_UNMAPPED_BASE is no longer page-aligned
> for bottom-up mmap, causing get_unmapped_area to choke on misaligned
> addresses.
>
> Reported-by: Christoffer Dall <cdall@cs.columbia.edu>
> Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
> ---
> arch/arm/include/asm/memory.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
> index 924320f..64c770d 100644
> --- a/arch/arm/include/asm/memory.h
> +++ b/arch/arm/include/asm/memory.h
> @@ -37,7 +37,7 @@
> */
> #define PAGE_OFFSET UL(CONFIG_PAGE_OFFSET)
> #define TASK_SIZE (UL(CONFIG_PAGE_OFFSET) - UL(SZ_16M))
> -#define TASK_UNMAPPED_BASE (UL(CONFIG_PAGE_OFFSET) / 3)
> +#define TASK_UNMAPPED_BASE ALIGN(TASK_SIZE / 3, SZ_16M)
>
> /*
> * The maximum size of a 26-bit user space task.
> --
> 1.8.0
>
prev parent reply other threads:[~2013-01-31 15:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-31 15:09 [PATCH v2 1/2] ARM: memory: use SZ_ constants for defining the virtual memory layout Will Deacon
2013-01-31 15:09 ` [PATCH v2 2/2] ARM: memory: define TASK_UNMAPPED_BASE in terms of TASK_SIZE Will Deacon
2013-01-31 15:58 ` Nicolas Pitre [this message]
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