Hi Albert,
On 02/04/2015 11:34 AM, Albert ARIBAUD wrote:
Hello Michal,
On Wed, 4 Feb 2015 10:56:02 +0100, Michal Simek michal.simek@xilinx.com wrote:
On 02/04/2015 04:11 AM, Masahiro Yamada wrote:
Hi Michal,
On Tue, 3 Feb 2015 10:11:39 +0100 Michal Simek michal.simek@xilinx.com wrote:
Hi Simon,
On 02/03/2015 03:02 AM, Masahiro Yamada wrote:
Hi.
On Mon, 2 Feb 2015 16:57:15 -0700 Simon Glass sjg@chromium.org wrote:
Hi Michal,
On 2 February 2015 at 08:31, Michal Simek michal.simek@xilinx.com wrote: > Targets with CONFIG_NEEDS_MANUAL_RELOC do not use REL/RELA > relocation (mostly only GOT) where functions aray are not > updated. This patch is fixing function pointers for DM core > and serial-uclass to ensure that relocated functions are called. > > Signed-off-by: Michal Simek michal.simek@xilinx.com > --- > > drivers/core/root.c | 64 ++++++++++++++++++++++++++++++++++++++++++ > drivers/serial/serial-uclass.c | 16 +++++++++++ > 2 files changed, 80 insertions(+)
How long will we have to carry this patch? It seems that if we add any new driver we will have to add more code like this?
This patch is unfortunate. Can we discontinue CONFIG_NEEDS_MANUAL_RELOC some day?
This patch (or similar one) has to be alive when we have platform which requires CONFIG_NEEDS_MANUAL_RELOC for full u-boot. There is an option to move to REL/RELA but the question is if all platforms have it/support it. Unfortunately I think that it will be in the tree for a long time.
If we use SPL, we do not have to relocate code, I think.
SPL doesn't have relocation that's why this code is not used there.
It is not what I meant.
If SPL can directly load the main u-boot image to the DRAM address where it is linked, we do not relocate the code in the main image.
Current behavior is that SPL is reading u-boot.img entry point which can be in any location and jump to it and u-boot self relocate to the end of memory. If SPL adds u-boot directly to the location where it should run after relocation then relocation is not needed. To ensure this capability (based on my poor GOT/REL/RELA) experience it means that SPL loads u-boot to that location and patch REL/RELA section based on this location and internal relocation should be skipped.
IOW, that SPL perform the work of relocate_code() in U-Boot -- at least, on ARM, where REL/RELA is used.
Maybe we don't understand each other. SPL is not relocate self to any other location. It just copies full u-boot to memory and jump to it and then full U-Boot relocate self to the end of memory.
This is definitely doable for REL/RELA case and it can also speedup boot process
Not sure about the speed-up, but never mind.
What I wanted to describe is that imagine case that SPL will does a little bit more steps when full u-boot should be loaded. It loads full u-boot to the end of memory and fix rel/rela section before passing control to it. IMHO (and not expert) removes one u-boot copy which current full u-boot does. (On the other hand if you want speedup boot you can boot OS directly).
(I don't think there is easy way how to solve this with just GOT relocation because of that MANUAL_RELOC code which is patching arrays with function pointers).
Even without importing SPL in the equation, switching from GOT to REL/RELA has enourmous advantages.
I believe you - I haven't finish this on Microblaze as we talked on IRC some time ago. I have to do what arm64 is doing in tools/relocate-rela.c.
Thanks, Michal