From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Thu, 9 Apr 2015 14:14:37 +0200 Subject: [PATCH v3 3/5] arm64: Documentation: clarify Image placement in physical RAM In-Reply-To: <20150409115417.GD18488@leverpostej> References: <1426698308-726-1-git-send-email-ard.biesheuvel@linaro.org> <1426698308-726-4-git-send-email-ard.biesheuvel@linaro.org> <20150409115417.GD18488@leverpostej> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 9 April 2015 at 13:54, Mark Rutland wrote: > Hi Ard, > > I take it that this (and patch 4) are superseded by the single-page > idmap approach, and when this is next posted you'll fold the series? > indeed. -- Ard. > On Wed, Mar 18, 2015 at 05:05:06PM +0000, Ard Biesheuvel wrote: >> The early init code maps the kernel image using statically >> allocated page tables. This means that we can only allow >> Image to be placed such that we can map its entire static >> footprint using a single table entry at all but the lowest >> level. So update the documentation to reflect that the Image >> should not cross a 512 MB boundary, which ensures the above >> on both 4k and 64k pages kernels. >> >> Reviewed-by: Mark Rutland >> Signed-off-by: Ard Biesheuvel >> --- >> Documentation/arm64/booting.txt | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/Documentation/arm64/booting.txt b/Documentation/arm64/booting.txt >> index ab5a90adece3..5949bdbe7aac 100644 >> --- a/Documentation/arm64/booting.txt >> +++ b/Documentation/arm64/booting.txt >> @@ -115,8 +115,9 @@ The Image must be placed text_offset bytes from a 2MB aligned base >> address near the start of usable system RAM and called there. Memory >> below that base address is currently unusable by Linux, and therefore it >> is strongly recommended that this location is the start of system RAM. >> -At least image_size bytes from the start of the image must be free for >> -use by the kernel. >> +The physical memory region consisting of image_size bytes counting from >> +the start of the image must be free for use by the kernel, and must not >> +cross a 512 MB physical alignment boundary. >> >> Any memory described to the kernel (even that below the 2MB aligned base >> address) which is not marked as reserved from the kernel e.g. with a >> -- >> 1.8.3.2 >> >>