| Message ID | 1360442010-7520-7-git-send-email-daniel.schwierzeck@gmail.com |
|---|---|
| State | Superseded |
| Delegated to: | Daniel Schwierzeck |
| Headers | show |
2013.02.09. 21:33 keltezéssel, daniel.schwierzeck@gmail.com írta: > From: Gabor Juhos <juhosg@openwrt.org> > > This section contain the table needed for dynamic > relocation. Also provide symbols for the relocation > code to access the table. > > Discard all sections which are not needed in the final > ELF binary and U-Boot image. Section .dynsym cannot be > discarded or GNU ld crashes otherwise. This section > will be stripped by GNU objcpy in a later patch. > > Signed-off-by: Gabor Juhos <juhosg@openwrt.org> > Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com> > --- > arch/mips/cpu/u-boot.lds | 24 +++++++++++++++++++++++- > 1 file changed, 23 insertions(+), 1 deletion(-) > > diff --git a/arch/mips/cpu/u-boot.lds b/arch/mips/cpu/u-boot.lds > index 4cd983a..cea9533 100644 > --- a/arch/mips/cpu/u-boot.lds > +++ b/arch/mips/cpu/u-boot.lds > @@ -70,7 +70,17 @@ SECTIONS > . = ALIGN(4); > __image_copy_end = .; > > - .bss : { > + .rel.dyn : { > + __rel_dyn_start = .; > + *(.rel.dyn) > + __rel_dyn_end = .; > + } > + > + .dynsym : { > + *(.dynsym) > + } This is not enough to avoid the binutils issue I have mentioned in the original patch. The issue is present after applying this series. The following example comes from the qemu_mips target compiled with the ELDK 5.3 toolchain: > $ mips-linux-objdump --disassemble u-boot | grep bfc005[67] > bfc00560: 00000000 nop > bfc00564: bfc31f74 cache 0x3,8052(s8) <--- __rel_dyn_end The offset of __rel_dyn_end: 0x0bfc31f74 - 0xbfc00000 = 0x31f74 = 204660 > bfc00568: bfc30804 cache 0x3,2052(s8) > bfc0056c: bfc30804 cache 0x3,2052(s8) > bfc00570: bfc2fa70 cache 0x2,-1424(s8) > bfc00574: 000001df 0x1df > bfc00578 <in_ram>: > bfc00578: 8d0bfffc lw t3,-4(t0) > bfc0057c: 8d0cfff8 lw t4,-8(t0) > $ ls -l u-boot.bin > -rw-r--r-- 1 juhosg root 204284 Feb 11 11:29 u-boot.bin 204660 - 204284 = 376 bytes are missing from the final u-boot.bin. -Gabor
2013/2/11 Gabor Juhos <juhosg@openwrt.org>: > 2013.02.09. 21:33 keltezéssel, daniel.schwierzeck@gmail.com írta: >> From: Gabor Juhos <juhosg@openwrt.org> >> >> This section contain the table needed for dynamic >> relocation. Also provide symbols for the relocation >> code to access the table. >> >> Discard all sections which are not needed in the final >> ELF binary and U-Boot image. Section .dynsym cannot be >> discarded or GNU ld crashes otherwise. This section >> will be stripped by GNU objcpy in a later patch. >> >> Signed-off-by: Gabor Juhos <juhosg@openwrt.org> >> Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com> >> --- >> arch/mips/cpu/u-boot.lds | 24 +++++++++++++++++++++++- >> 1 file changed, 23 insertions(+), 1 deletion(-) >> >> diff --git a/arch/mips/cpu/u-boot.lds b/arch/mips/cpu/u-boot.lds >> index 4cd983a..cea9533 100644 >> --- a/arch/mips/cpu/u-boot.lds >> +++ b/arch/mips/cpu/u-boot.lds >> @@ -70,7 +70,17 @@ SECTIONS >> . = ALIGN(4); >> __image_copy_end = .; >> >> - .bss : { >> + .rel.dyn : { >> + __rel_dyn_start = .; >> + *(.rel.dyn) >> + __rel_dyn_end = .; >> + } >> + >> + .dynsym : { >> + *(.dynsym) >> + } > > This is not enough to avoid the binutils issue I have mentioned in the original > patch. The issue is present after applying this series. > > The following example comes from the qemu_mips target compiled with the ELDK 5.3 > toolchain: > >> $ mips-linux-objdump --disassemble u-boot | grep bfc005[67] >> bfc00560: 00000000 nop >> bfc00564: bfc31f74 cache 0x3,8052(s8) <--- __rel_dyn_end > > The offset of __rel_dyn_end: > 0x0bfc31f74 - 0xbfc00000 = 0x31f74 = 204660 > >> bfc00568: bfc30804 cache 0x3,2052(s8) >> bfc0056c: bfc30804 cache 0x3,2052(s8) >> bfc00570: bfc2fa70 cache 0x2,-1424(s8) >> bfc00574: 000001df 0x1df >> bfc00578 <in_ram>: >> bfc00578: 8d0bfffc lw t3,-4(t0) >> bfc0057c: 8d0cfff8 lw t4,-8(t0) > >> $ ls -l u-boot.bin >> -rw-r--r-- 1 juhosg root 204284 Feb 11 11:29 u-boot.bin > > 204660 - 204284 = 376 bytes are missing from the final u-boot.bin. > > -Gabor > that's weird. Actually I checked after each patch if the *_end symbols match the U-Boot binary size. Now I checked again with different toolchains (gcc-4.[5,6,7], binutils-2.[21.53,22] and I have again that binutils issue. But all toolchains have one in common (tested with qemu_mips): __rel_dyn_end - __rel_dyn_start = 0x1770 size from readelf = 0x15f8 Another problem is that your .deadcode workaround does not work anymore for me. It does not matter how I arrange or drop the unneeded sections, the size of .rel.dyn remains at 0x1770. I'll try to find another solution.
diff --git a/arch/mips/cpu/u-boot.lds b/arch/mips/cpu/u-boot.lds index 4cd983a..cea9533 100644 --- a/arch/mips/cpu/u-boot.lds +++ b/arch/mips/cpu/u-boot.lds @@ -70,7 +70,17 @@ SECTIONS . = ALIGN(4); __image_copy_end = .; - .bss : { + .rel.dyn : { + __rel_dyn_start = .; + *(.rel.dyn) + __rel_dyn_end = .; + } + + .dynsym : { + *(.dynsym) + } + + .bss __rel_dyn_start (OVERLAY) : { __bss_start = .; *(.sbss.*) *(.bss.*) @@ -78,4 +88,16 @@ SECTIONS . = ALIGN(4); __bss_end = .; } + + /DISCARD/ : { + *(.dynbss) + *(.dynstr) + *(.dynamic) + *(.interp) + *(.hash) + *(.gnu.*) + *(.plt) + *(.got.plt) + *(.rel.plt) + } }