| Message ID | 20220628151307.35561-2-joey.gouly@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vDSO linkerscript follow up | expand |
On 28/06/2022 16:13, Joey Gouly wrote: > These show up when building with clang+lld. > > Signed-off-by: Joey Gouly <joey.gouly@arm.com> > Cc: Will Deacon <will@kernel.org> > Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> > --- > arch/arm64/kernel/vdso32/vdso.lds.S | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/arm64/kernel/vdso32/vdso.lds.S b/arch/arm64/kernel/vdso32/vdso.lds.S > index 120cf422036f..e2f8ced571d6 100644 > --- a/arch/arm64/kernel/vdso32/vdso.lds.S > +++ b/arch/arm64/kernel/vdso32/vdso.lds.S > @@ -60,6 +60,7 @@ SECTIONS > } > > ELF_DETAILS > + .ARM.exidx : { *(.ARM.exidx*) } > .ARM.attributes 0 : { *(.ARM.attributes) } > > /DISCARD/ : {
Hi Joey, On Tue, Jun 28, 2022 at 04:13:06PM +0100, Joey Gouly wrote: > These show up when building with clang+lld. > > Signed-off-by: Joey Gouly <joey.gouly@arm.com> > Cc: Will Deacon <will@kernel.org> > Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> > --- > arch/arm64/kernel/vdso32/vdso.lds.S | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/arm64/kernel/vdso32/vdso.lds.S b/arch/arm64/kernel/vdso32/vdso.lds.S > index 120cf422036f..e2f8ced571d6 100644 > --- a/arch/arm64/kernel/vdso32/vdso.lds.S > +++ b/arch/arm64/kernel/vdso32/vdso.lds.S > @@ -60,6 +60,7 @@ SECTIONS > } > > ELF_DETAILS > + .ARM.exidx : { *(.ARM.exidx*) } > .ARM.attributes 0 : { *(.ARM.attributes) } > > /DISCARD/ : { > -- > 2.17.1 > This patch is now in -next as commit 5c4fb60816ea ("arm64: vdso32: add ARM.exidx* sections"), which causes the following errors with ld.lld 11: ld.lld: error: could not allocate headers ld.lld: error: unable to place section .text at file offset [0x2A0, 0xBB1]; check your linker script for overflows ld.lld: error: unable to place section .comment at file offset [0xBB2, 0xC8A]; check your linker script for overflows ld.lld: error: unable to place section .symtab at file offset [0xC8C, 0xE0B]; check your linker script for overflows ld.lld: error: unable to place section .strtab at file offset [0xE0C, 0xF1C]; check your linker script for overflows ld.lld: error: unable to place section .shstrtab at file offset [0xF1D, 0xFAA]; check your linker script for overflows ld.lld: error: section .ARM.exidx file range overlaps with .hash >>> .ARM.exidx range is [0x90, 0xCF] >>> .hash range is [0xB4, 0xE3] ld.lld: error: section .hash file range overlaps with .ARM.attributes >>> .hash range is [0xB4, 0xE3] >>> .ARM.attributes range is [0xD0, 0x10B] ld.lld: error: section .ARM.attributes file range overlaps with .dynsym >>> .ARM.attributes range is [0xD0, 0x10B] >>> .dynsym range is [0xE4, 0x133] ld.lld: error: section .ARM.exidx virtual address range overlaps with .hash >>> .ARM.exidx range is [0x90, 0xCF] >>> .hash range is [0xB4, 0xE3] ld.lld: error: section .ARM.exidx load address range overlaps with .hash >>> .ARM.exidx range is [0x90, 0xCF] >>> .hash range is [0xB4, 0xE3] I bisected LLVM to see what fixed this in ld.lld 12 and I landed on commit ec29538af2e0 ("[ELF] Assign file offsets of non-SHF_ALLOC after SHF_ALLOC and set sh_addr=0 to non-SHF_ALLOC") [1]. We could bump the minimum version of LLVM to 12 over this but the following diff appears to resolve it for me, although I am not sure as to why. diff --git a/arch/arm64/kernel/vdso32/vdso.lds.S b/arch/arm64/kernel/vdso32/vdso.lds.S index 6e67a6524d58..c25bed8e6df1 100644 --- a/arch/arm64/kernel/vdso32/vdso.lds.S +++ b/arch/arm64/kernel/vdso32/vdso.lds.S @@ -56,8 +56,8 @@ SECTIONS .rel.dyn : { *(.rel*) } - ELF_DETAILS .ARM.exidx : { *(.ARM.exidx*) } + ELF_DETAILS .ARM.attributes 0 : { *(.ARM.attributes) } /DISCARD/ : { I just noticed that the .ARM.exidx section (ARM_UNWIND_SECTIONS) is placed before the sections the error mentions (ARM_DETAILS) in arch/arm/kernel/vmlinux.lds.S, where we do not see any errors with LLVM 11. Looking at the section headers, it seems like it should be okay? With LLVM 15 (current git) at 4274929c7ee6f442: arch/arm64/kernel/vdso32/vdso.so: file format elf32-littlearm Sections: Idx Name Size VMA Type 0 00000000 00000000 1 .hash 00000030 000000b4 2 .dynsym 00000050 000000e4 3 .dynstr 0000006f 00000134 4 .gnu.version 0000000a 000001a4 5 .gnu.version_d 00000038 000001b0 6 .note 00000054 000001e8 7 .dynamic 00000058 0000023c 8 .text 0000092a 00000294 TEXT 9 .shstrtab 0000006d 00000000 10 .ARM.exidx 00000040 00000bc0 11 .ARM.attributes 0000003c 00000000 With LLVM 11 at 4274929c7ee6f442 + above diff: arch/arm64/kernel/vdso32/vdso.so: file format elf32-littlearm Sections: Idx Name Size VMA Type 0 00000000 00000000 1 .hash 00000030 000000b4 2 .dynsym 00000050 000000e4 3 .dynstr 0000006f 00000134 4 .gnu.version 0000000a 000001a4 5 .gnu.version_d 00000038 000001b0 6 .note 00000054 000001e8 7 .dynamic 00000058 0000023c 8 .rodata 00000000 000002a0 TEXT 9 .text 00000912 000002a0 TEXT 10 .ARM.exidx 00000040 00000bb4 11 .shstrtab 00000075 00000000 12 .ARM.attributes 0000003c 00000000 With LLVM 15 at 4274929c7ee6f442 + above diff: arch/arm64/kernel/vdso32/vdso.so: file format elf32-littlearm Sections: Idx Name Size VMA Type 0 00000000 00000000 1 .hash 00000030 000000b4 2 .dynsym 00000050 000000e4 3 .dynstr 0000006f 00000134 4 .gnu.version 0000000a 000001a4 5 .gnu.version_d 00000038 000001b0 6 .note 00000054 000001e8 7 .dynamic 00000058 0000023c 8 .rodata 00000000 000002a0 TEXT 9 .text 00000912 000002a0 TEXT 10 .ARM.exidx 00000040 00000bb4 11 .shstrtab 00000075 00000000 12 .ARM.attributes 0000003c 00000000 [1]: https://github.com/llvm/llvm-project/commit/ec29538af2e0886a65f479d6a533956a1c478132 Cheers, Nathan
Hi Nathan, On Wed, Jun 29, 2022 at 01:10:10PM -0700, Nathan Chancellor wrote: > Hi Joey, > > On Tue, Jun 28, 2022 at 04:13:06PM +0100, Joey Gouly wrote: > > These show up when building with clang+lld. > > > > Signed-off-by: Joey Gouly <joey.gouly@arm.com> > > Cc: Will Deacon <will@kernel.org> > > Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> > > --- > > arch/arm64/kernel/vdso32/vdso.lds.S | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/arch/arm64/kernel/vdso32/vdso.lds.S b/arch/arm64/kernel/vdso32/vdso.lds.S > > index 120cf422036f..e2f8ced571d6 100644 > > --- a/arch/arm64/kernel/vdso32/vdso.lds.S > > +++ b/arch/arm64/kernel/vdso32/vdso.lds.S > > @@ -60,6 +60,7 @@ SECTIONS > > } > > > > ELF_DETAILS > > + .ARM.exidx : { *(.ARM.exidx*) } > > .ARM.attributes 0 : { *(.ARM.attributes) } > > > > /DISCARD/ : { > > -- > > 2.17.1 > > > > This patch is now in -next as commit 5c4fb60816ea ("arm64: vdso32: add > ARM.exidx* sections"), which causes the following errors with ld.lld 11: Sorry for the breakage. > > ld.lld: error: could not allocate headers > ld.lld: error: unable to place section .text at file offset [0x2A0, 0xBB1]; check your linker script for overflows > ld.lld: error: unable to place section .comment at file offset [0xBB2, 0xC8A]; check your linker script for overflows > ld.lld: error: unable to place section .symtab at file offset [0xC8C, 0xE0B]; check your linker script for overflows > ld.lld: error: unable to place section .strtab at file offset [0xE0C, 0xF1C]; check your linker script for overflows > ld.lld: error: unable to place section .shstrtab at file offset [0xF1D, 0xFAA]; check your linker script for overflows > ld.lld: error: section .ARM.exidx file range overlaps with .hash > >>> .ARM.exidx range is [0x90, 0xCF] > >>> .hash range is [0xB4, 0xE3] > > ld.lld: error: section .hash file range overlaps with .ARM.attributes > >>> .hash range is [0xB4, 0xE3] > >>> .ARM.attributes range is [0xD0, 0x10B] > > ld.lld: error: section .ARM.attributes file range overlaps with .dynsym > >>> .ARM.attributes range is [0xD0, 0x10B] > >>> .dynsym range is [0xE4, 0x133] > > ld.lld: error: section .ARM.exidx virtual address range overlaps with .hash > >>> .ARM.exidx range is [0x90, 0xCF] > >>> .hash range is [0xB4, 0xE3] > > ld.lld: error: section .ARM.exidx load address range overlaps with .hash > >>> .ARM.exidx range is [0x90, 0xCF] > >>> .hash range is [0xB4, 0xE3] > > I bisected LLVM to see what fixed this in ld.lld 12 and I landed on > commit ec29538af2e0 ("[ELF] Assign file offsets of non-SHF_ALLOC after > SHF_ALLOC and set sh_addr=0 to non-SHF_ALLOC") [1]. > > We could bump the minimum version of LLVM to 12 over this but the > following diff appears to resolve it for me, although I am not sure as > to why. > > diff --git a/arch/arm64/kernel/vdso32/vdso.lds.S b/arch/arm64/kernel/vdso32/vdso.lds.S > index 6e67a6524d58..c25bed8e6df1 100644 > --- a/arch/arm64/kernel/vdso32/vdso.lds.S > +++ b/arch/arm64/kernel/vdso32/vdso.lds.S > @@ -56,8 +56,8 @@ SECTIONS > > .rel.dyn : { *(.rel*) } > > - ELF_DETAILS > .ARM.exidx : { *(.ARM.exidx*) } > + ELF_DETAILS > .ARM.attributes 0 : { *(.ARM.attributes) } > > /DISCARD/ : { > > I just noticed that the .ARM.exidx section (ARM_UNWIND_SECTIONS) > is placed before the sections the error mentions (ARM_DETAILS) in > arch/arm/kernel/vmlinux.lds.S, where we do not see any errors with LLVM > 11. Looking at the section headers, it seems like it should be okay? I think it's good like this too, will you send it out as a patch? Thanks, Joey
diff --git a/arch/arm64/kernel/vdso32/vdso.lds.S b/arch/arm64/kernel/vdso32/vdso.lds.S index 120cf422036f..e2f8ced571d6 100644 --- a/arch/arm64/kernel/vdso32/vdso.lds.S +++ b/arch/arm64/kernel/vdso32/vdso.lds.S @@ -60,6 +60,7 @@ SECTIONS } ELF_DETAILS + .ARM.exidx : { *(.ARM.exidx*) } .ARM.attributes 0 : { *(.ARM.attributes) } /DISCARD/ : {
These show up when building with clang+lld. Signed-off-by: Joey Gouly <joey.gouly@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> --- arch/arm64/kernel/vdso32/vdso.lds.S | 1 + 1 file changed, 1 insertion(+)