Adding the Coldfire maintainers on Cc.
On Fri, Jul 26, 2024 at 4:46 PM Peter LaDow <pla...@gmail.com> wrote:
>
> After some digging it appears that this is a toolchain issue. It seems the
> linker fixups are sometimes not computed correctly. For example, in
> board_init_f_init_reserve, the object file disassembled has:
>
> 00000000 <board_init_f_init_reserve>:
> 0: 2f02 movel %d2,%sp@-
> 2: 242f 0008 movel %sp@(8),%d2
> 6: 4878 00c0 pea c0 <board_init_f_init_reserve+0xc0>
> a: 42a7 clrl %sp@-
> c: 2f02 movel %d2,%sp@-
> e: 61ff 0000 0000 bsrl 10 <board_init_f_init_reserve+0x10>
> 14: 2f02 movel %d2,%sp@-
> 16: 61ff 0000 0000 bsrl 18 <board_init_f_init_reserve+0x18>
> 1c: 0682 0000 00c0 addil #192,%d2
> 22: 4fef 0010 lea %sp@(16),%sp
> 26: 2047 moveal %d7,%a0
> 28: 2142 00a0 movel %d2,%a0@(160)
> 2c: 241f movel %sp@+,%d2
> 2e: 4e75 rts
>
> But when I disassemble the final linked u-boot output:
>
> 0000f646 <board_init_f_init_reserve>:
> f646: 2f02 movel %d2,%sp@-
> f648: 242f 0008 movel %sp@(8),%d2
> f64c: 4878 00c0 pea c0 <_vectors+0xc0>
> f650: 42a7 clrl %sp@-
> f652: 2f02 movel %d2,%sp@-
> f654: 61ff 0001 44da bsrl 23b30 <_etext+0x138>
> f65a: 2f02 movel %d2,%sp@-
> f65c: 61ff ffff ffd2 bsrl f630 <arch_setup_gd>
> f662: 0682 0000 00c0 addil #192,%d2
> f668: 4fef 0010 lea %sp@(16),%sp
> f66c: 2047 moveal %d7,%a0
> f66e: 2142 00a0 movel %d2,%a0@(160)
> f672: 241f movel %sp@+,%d2
> f674: 4e75 rts
>
> Note the pea c0 instruction. The object file has
> board_init_f_init_reserve+0xc0 as the argument, but the final linker has
> 0xc0, meaning board_init_f_init_reserve is being set to 0 after linking.
>
> Also, note the first bsrl instruction, which is not setup correctly
> either. This is a call to memset. This points to _etext+0x138, which is
> not a code region Note that 0x239f8 + 0x138 = 0x23b30. But in the final
> uboot, memset is at 0x1f030.
>
> In the call to memset(), objdump shows the relocation:
>
> RELOCATION RECORDS FOR [.text.board_init_f_init_reserve]:
> OFFSET TYPE VALUE
> 00000010 R_68K_PLT32 memset
> 00000018 R_68K_PLT32 arch_setup_gd
>
> So it seems only when linking outside the same compilation unit that the
> relocations aren't set correctly.
>
> I'm not sure where to look for a solution. Or how to search for an
> answer. I've done some digging on Google, but nothing points to a clear
> answer. Anyone seen something similar?
>
> To love for the sake of being loved is human, but to love for the sake of
> loving is angelic. -- Alphonse de Lamartine.
>
>
> On Thu, Jul 25, 2024 at 14:35 Peter LaDow <pla...@gmail.com> wrote:
> >
> > I'm trying to add support for a custom Colfire based board. I have
> > things building, but the final linked vectors in start.S do not point
> > to _start. In start.S I have:
> >
> > _vectors:
> > .long 0x00000000 /* Flash offset is 0 until we setup CS0 */
> > .long _START
> >
> > .long _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
> > .long _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
> > .long _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
> >
> > Dumping the symbols in the final u-boot yields:
> >
> > $ m68k-linux-gnu-nm -n u-boot
> > 00000000 A __fixup_entries
> > 00000000 A __got2_entries
> > 00000000 t _vectors
> > 00000400 T _start
> > 0000047e T relocate_code
> > 000004ae t fixloop
> >
> > But then dumping the raw binary:
> >
> > u-boot: file format elf32-m68k
> >
> > Contents of section .text:
> > 00000 00000000 00000000 00000516 00000516 ................
> > 00010 00000516 00000516 00000516 00000516 ................
> > 00020 00000516 00000516 00000516 00000516 ................
> > 00030 00000516 00000516 00000516 00000516 ................
> >
> > Note at offset 4 it is 0x00000000, not 0x00000400 as I'd expect.
> >
> > The final linker script has:
> >
> > OUTPUT_ARCH(m68k)
> > ENTRY(_start)
> > SECTIONS
> > {
> > .text :
> > {
> > arch/m68k/cpu/mcf548x/start.o (.text*)
> > . = DEFINED(env_offset) ? env_offset : .; env/embedded.o(.text*);
> > *(.text*)
> > }
> >
> >
> > It is difficult to search the archives, and so far I haven't found
> > anything. Any help would be appreciated.
> >
> > --
> > To love for the sake of being loved is human, but to love for the sake
> > of loving is angelic. -- Alphonse de Lamartine.
