On 27.06.17 13:20, Michal Simek wrote:
Hi,
On 27.6.2017 13:01, Alexander Graf wrote:
I don't think that's going to work - at least not without compiler flag changes. By default, gcc will happily generate unaligned accesses. If you disable dcache, these will trap.
What's that compiler flags we should be using to avoid that?
It's a combination of
-mstrict-align
plus crossing fingers with lots of praying plus making sure that every code you call also follows -mstrict-align plus double-checking that you don't break the kernel booting ABI:
http://elixir.free-electrons.com/linux/v4.12-rc7/source/Documentation/arm64/...
In the booti case, disabling dcache seems to be legitimate. In the bootefi case however, it's not.
So you will also need to set CONFIG_EFI_LOADER to depend on !CONFIG_SYS_DCACHE_OFF which means you will want to convert CONFIG_SYS_DCACHE_OFF to Kconfig first :).
The reason for this change is to have really small u-boot which fits to OCM without DDR to be able to do initial programming.
Yup, makes sense. I'm just slightly scared by the idea :).
Alex