From mboxrd@z Thu Jan 1 00:00:00 1970 From: mark.rutland@arm.com (Mark Rutland) Date: Thu, 9 Apr 2015 12:54:17 +0100 Subject: [PATCH v3 3/5] arm64: Documentation: clarify Image placement in physical RAM In-Reply-To: <1426698308-726-4-git-send-email-ard.biesheuvel@linaro.org> References: <1426698308-726-1-git-send-email-ard.biesheuvel@linaro.org> <1426698308-726-4-git-send-email-ard.biesheuvel@linaro.org> Message-ID: <20150409115417.GD18488@leverpostej> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Ard, I take it that this (and patch 4) are superseded by the single-page idmap approach, and when this is next posted you'll fold the series? Thanks, Mark. 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 > >