Hello Darius, Darius Augulis wrote: > the code for clearing bss section for most ARM cores looks like this > or very similar: > > clear_bss: > #ifndef CONFIG_PRELOADER > ldr r0, _bss_start_ofs > ldr r1, _bss_end_ofs > ldr r3, _TEXT_BASE /* Text base */ > mov r4, r7 /* reloc addr */ > add r0, r0, r4 > add r1, r1, r4 > mov r2, #0x00000000 /* clear */ > > clbss_l:str r2, [r0] /* clear loop... */ > add r0, r0, #4 > cmp r0, r1 > bne clbss_l > #endif /* #ifndef CONFIG_PRELOADER */ > > > IMO, if relocation is skipped, r4 should be loaded with value of > _TEXT_BASE, not reloc address?
Hmm.. I think the question is, is CONFIG_SKIP_RELOCATE_UBOOT not obsolete? > It seems like r3 is prepared for this but, it's somehow missing? It's > not used at all. Here you are right. I think r3 is an artifact from the GOT relocation. This should be reworked (added Albert Aribaud to cc, because he did the elf relocation work) > Maybe it could be reason why I'm facing strange problem, when after > relocating uboot with nand_spl no one command is not working. > I debugged that command table is empty. I think this ASM code clears > not bss area but something else. If you have defined CONFIG_SKIP_RELOCATE_UBOOT, yes. Please remove this define. > Also relocation code looks a bit strange: > > .globl relocate_code > relocate_code: > mov r4, r0 /* save addr_sp */ > mov r5, r1 /* save addr of gd */ > mov r6, r2 /* save addr of destination */ > mov r7, r2 /* save addr of destination */ > > /* Set up the stack */ > stack_setup: > mov sp, r4 > > adr r0, _start > ldr r2, _TEXT_BASE > ldr r3, _bss_start_ofs > add r2, r0, r3 /* r2 <- source end address */ > cmp r0, r6 > beq clear_bss > > r0 is compared to r6, which contains reloc address. All instructions > between loading r0 and comparison are confusing, because they do not > impact comparison result. > Also they do not matter in clear_bss so I think would be great to > change code like this: > > mov sp, r4 > > adr r0, _start > cmp r0, r6 > beq clear_bss > ldr r2, _TEXT_BASE > ldr r3, _bss_start_ofs > add r2, r0, r3 /* r2 <- source end address */ > > Any comments are welcome! Yep, please send a patch for this issue. bye, Heiko -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
