Hello Reinhard,
Reinhard Meyer wrote:
Dear Albert ARIBAUD,
I try to understand how the relocation process could handle pointers (to functions or other data) in const or data sections. Your code cannot know what is data and what is a pointer that needs adjustment?
Best Regards, Reinhard
Hi Reinhart,
Short answer - the relocation process does not handle pointers inside data structures.
And yes, this means the content arrays of pointers such as init_sequence is not relocated. Been there, done that, can give you one of the
The init_sequence should not called anymore after relocation, as it is the init_sequence ... or?
tee-shirts I got :)
ATM I have not found a way to fix this, except making the code which uses the pointers aware that the are location-sensitive and fix them when using them.
That means that things like this cannot work (with relocation), unless adding the relocation offset before using the pointer:
Yep, you have to fix these pointers after relocation ...
const struct { const u8 shift; const u8 idcode; struct spi_flash *(*probe) (struct spi_slave *spi, u8 *idcode); } flashes[] = { #ifdef CONFIG_SPI_FLASH_SPANSION { 0, 0x01, spi_flash_probe_spansion, }, #endif
[...]
#ifdef CONFIG_SPI_FRAM_RAMTRON { 6, 0xc2, spi_fram_probe_ramtron, }, # ifdef CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC { 0, 0xff, spi_fram_probe_ramtron, }, # endif # undef IDBUF_LEN # define IDBUF_LEN 9 /* we need to read 6+3 bytes */ #endif };
And I think there are more places of this type in u-boot...
Yes, maybe. But relocation as I did for arm, also works on m68k, sparc, mips, avr32 and they must do also this fixups, so for common functions (except the new env handling, which I think got never tested on this architectures?) should work ...
As I just searching in code: there is a env_relocate() function (which get called from arch/arm/lib/board.c board_init_r()), but it did not the necessary work for subcommandtable fixup... I think this should be the right place to do this ... or?
bye, Heiko