Hi Quentin,
On 2024-02-12 11:37, Quentin Schulz wrote:
Hi Jonas,
On 2/12/24 01:59, Jonas Karlman wrote:
With the stack and text base used by U-Boot SPL and proper on RK3399 there is a high likelihood of overlapping when U-Boot proper + FDT nears 1 MiB in size.
Currently the following memory layout is used:
- 0x00000000 (@0 MiB): U-Boot SPL text base
- 0x00040000 (@256 KiB): TF-A
- 0x00200000 (@2 MiB): U-Boot proper text base
- 0x00300000 (@3 MiB): U-Boot proper init stack
- 0x00400000 (@4 MiB): U-Boot SPL init stack
- 0x00400000 (@4 MiB): U-Boot SPL bss
- 0x02000000 (@64 MiB): U-Boot SPL reloc stack
- 0x08400000 (@132 MiB): optional OPTEE
SPL load TF-A, U-Boot proper and optional OPTEE after SPL stack has relocated, meaning that there is room for close to 2 MiB (@2-4 MiB). However, the initial stack used by U-Boot proper is limiting the size of U-Boot proper + FDT to below 1 MiB (@2-3 MiB).
Instead change to use the following memory layout:
- 0x00000000 (@0 MiB): U-Boot SPL text base
- 0x00040000 (@256 KiB): TF-A
- 0x00200000 (@2 MiB): U-Boot proper text base
- 0x00400000 (@4 MiB): U-Boot SPL init stack
- 0x00800000 (@8 MiB): U-Boot proper init stack (changed)
- 0x02000000 (@32 MiB): U-Boot SPL bss (changed)
- 0x04000000 (@64 MiB): U-Boot SPL reloc stack
- 0x08400000 (@132 MiB): optional OPTEE
This should leave room for loading and running a U-Boot proper close to 6 MiB (@2-8 MiB) in size. When U-Boot proper has relocated is should be possible to use @2-132 MiB and @164 MiB+ for scripts, kernel etc.
With the moved SPL reloc stack it is also possible to use a much larger malloc area in SPL, e.g. using default SPL_STACK_R_MALLOC_SIMPLE_LEN.
Signed-off-by: Jonas Karlman jonas@kwiboo.se
Do we not need to update memory addresses in the environment as well?
The addresses in environment is to my knowledge only used in U-Boot proper after relocation. And at that time we should be free to use @2+ MiB up to somewhere close to gd ram_top/relocaddr. The optional Rockchip OPTEE blobb may occupy @132-164 MiB, but I do not think loading OPTEE blobs works as-is, so that may not be a big issue.
So to my knowledge we do not need to update any of the memory addresses in the environment as well.
scriptaddr=0x00500000
This is at 5MiB if I'm not mistaken?
Basically everything in include/configs/rk3399_common.h in ENV_MEM_LAYOUT_SETTINGS needs to be updated to be located after 164MiB?
Did I misunderstand something? I find it weird the current values seems to be located after U-Boot SPL bss and that e.g.
kernel_addr_r=0x02080000
is at 32.5MiB, and with U-Boot SPL reloc stack currently at 64MiB... a 31.5+MiB kernel Image would mess up the data there? (what do we need it for BTW once in U-boot proper after relocation?).
After SPL has jumped to TF-A and U-boot proper any memory used by SPL can be overwritten/used for something else.
My understanding is as follow: - SPL always need access to bss - SPL need access to init stack until it has relocated to reloc stack - SPL will load FIT images using the reloc stack, at this time only SPL code, bss and reloc stack matters - U-boot proper will use its init stack until it has relocated to end of memory. Until U-Boot proper has relocated it will use init stack - We could use same memory position for init stack for SPL and proper, e.g. SPL_SHARES_INIT_SP_ADDR=y without any issue - After U-Boot proper has relocated we should be free to use @2+ MiB up to where U-Boot proper was relocated.
Side question, what about making those values the default for RK3399 instead of having it in each defconfig? This could grow quickly out of hands to move this to the Kconfig symbol itself, so not sure it's that interesting to the project, but raising this anyway.
Agree, was trying to define these as defaults in soc Kconfig, but that rearranged some values in other defconfigs so I avoided doing that in this series. Also touching each defconfig helped me ping board maintainers of the change.
Hopefully a follow-up series can move these, and other options, into soc Kconfig.
Regards, Jonas
Cheers, Quentin