- Recommend that the kernel be placed under 128MiB, this is required if
CONFIG_AUTO_ZRELADDR=y and good (or at least not bad) advice even if
CONFIG_AUTO_ZRELADDR=n.
- Recommend that a zImage kernel be placed above 32MiB, this avoids the need
to relocate prior to decompression, which can speed up boot.
- Add basic info on the requirements when loading a raw (non-zImage) kernel
which are stricter than the zImage requirements.
- Recommend that the DTB be placed after the 128MiB boundary, avoiding any
potential conflict with the kernel decompressor, and within the lowmem
region. In practice it could follow the kernel loaded after 32MiB,
assuming the kernel decompesses to less than 32MiB, but the 128MiB
recommendation is simple and unambiguous.
- Add similar recommendation regarding initramfs.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dave Martin <dave.martin@linaro.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Roy Franz <roy.franz@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Document the possibility of the kernel being entered in HYP mode.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Currently, the documented kernel entry requirements are not
explicit about whether the kernel should be entered in ARM or
Thumb, leading to an ambiguitity about how to enter Thumb-2
kernels. As a result, the kernel is reliant on the zImage
decompressor to enter the kernel proper in the correct instruction
set state.
This patch changes the boot entry protocol for head.S and Image to
be the same as for zImage: in all cases, the kernel is now entered
in ARM.
Documentation/arm/Booting is updated to reflect this new policy.
A different rule will be needed for Cortex-M class CPUs as and when
support for those lands in mainline, since these CPUs don't support
the ARM instruction set at all: a note is added to the effect that
the kernel must be entered in Thumb on such systems.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
v6: typo fixes
v5: clarified that dtb should be aligned on a 64 bit boundary in RAM.
v3: added details to Documentation/arm/Booting
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This reverts commit 9830fcd6f6.
The ARM dt support has not been merged yet; this documentation update
was premature.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Ian Campbell