From mboxrd@z Thu Jan  1 00:00:00 1970
From: catalin.marinas@arm.com (Catalin Marinas)
Date: Tue, 1 Mar 2016 15:39:58 +0000
Subject: [PATCH v2 5/9] arm64: mm: move vmemmap region right below the
 linear region
In-Reply-To: <1456757084-1078-6-git-send-email-ard.biesheuvel@linaro.org>
References: <1456757084-1078-1-git-send-email-ard.biesheuvel@linaro.org>
 <1456757084-1078-6-git-send-email-ard.biesheuvel@linaro.org>
Message-ID: <20160301153957.GA22107@localhost.localdomain>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, Feb 29, 2016 at 03:44:40PM +0100, Ard Biesheuvel wrote:
> @@ -404,6 +404,12 @@ void __init mem_init(void)
>  	BUILD_BUG_ON(TASK_SIZE_32			> TASK_SIZE_64);
>  #endif
>  
> +	/*
> +	 * Make sure we chose the upper bound of sizeof(struct page)
> +	 * correctly.
> +	 */
> +	BUILD_BUG_ON(sizeof(struct page) > (1 << STRUCT_PAGE_MAX_SHIFT));

Since with the vmemmap fix you already assume that PAGE_OFFSET is half
of the VA space, we should add another check on PAGE_OFFSET !=
UL(0xffffffffffffffff) << (VA_BITS - 1), just in case someone thinks
they could map a bit of extra RAM without going for a larger VA.

-- 
Catalin