-----Original Message----- From: u-boot-users-bounces@lists.sourceforge.net [mailto:u-boot-users-bounces@lists.sourceforge.net] On Behalf Of Jean-Christophe PLAGNIOL-VILLARD Sent: den 26 juli 2008 16:03 To: Grant Likely Cc: u-boot-users@lists.sourceforge.net; Wolfgang Denk; vb; Jerry Van Baren; Haavard Skinnemoen Subject: Re: [U-Boot-Users] Changing u-boot relocation scheme
On 01:57 Sat 26 Jul , Grant Likely wrote:
On Fri, Jul 25, 2008 at 1:28 PM, kenneth johansson kenneth@southpole.se wrote:
I was afraid that what was needed was more or less a complete linker but it looks like if one generate the dynamic reloc table a much simpler linker(relocation function) is needed. Still probably a lot more complex than the GOT and fixup code that is just a loop over a table. We may need a case also ;-)
The GOT relocation works. It works really well. As long as gcc and ld put the correct GOT bits into the GOT table. It seems not all versions of gcc do it in the same way with the same flags.
Why not set the code depending on the GCC version?
For fun I had a look into eabi.asm code at http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/config/rs6000/eabi.asm?rev=1.1... and I noticed one difference: The __eabi_uconvert() function skips NULL ptrs.
Perhaps this is the missing piece needed in start.S for PPC?
__eabi_convert pasted below for convenience.
Jocke
FUNC_START(__eabi_convert) cmplw 1,3,4 /* any pointers to convert? */ subf 5,3,4 /* calculate number of words to convert */ bclr 4,4 /* return if no pointers */
srawi 5,5,2 addi 3,3,-4 /* start-4 for use with lwzu */ mtctr 5
.Lcvt: lwzu 6,4(3) /* pointer to convert */ cmpwi 0,6,0 beq- .Lcvt2 /* if pointer is null, don't convert */
add 6,6,12 /* convert pointer */ stw 6,0(3) .Lcvt2: bdnz+ .Lcvt blr