Re: [PATCH 0/1] x86/boot: lld fix
On Wed, May 20, 2020 at 07:12:17PM -0700, Fangrui Song wrote:
> On 2020-05-20, Arvind Sankar wrote:
> >On Wed, May 20, 2020 at 06:56:53PM -0400, Arvind Sankar wrote:
> >> arch/x86/boot/setup.elf currently has an orphan section .text.startup,
> >> and lld git as of ebf14d9b6d8b is breaking on 64-bit due to what seems
> >> to be a change in behavior on orphan section placement (details in patch
> >> commit message).
> >>
> >> I'm not sure if this was an intentional change in lld, but it seems like
> >> a good idea to explicitly include .text.startup anyway.
> >>
> >> Arvind Sankar (1):
> >> x86/boot: Add .text.startup to setup.ld
> >>
> >> arch/x86/boot/setup.ld | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> --
> >> 2.26.2
> >>
>
> I found your PATCH 1/1 on https://lkml.org/lkml/2020/5/20/1491
>
> - .text : { *(.text) }
> + .text : { *(.text.startup) *(.text) }
>
> The LLD behavior change was introduced in
> https://reviews.llvm.org/D75225 (will be included in 11.0.0)
> It was intended to match GNU ld.
>
> But yes, orphan section placement is still different in the two linkers.
>
> Placing .text.startup before .text seems good.
> In GNU ld's internal linker script (ld --verbose),
> .text.startup is placed before .text
>
> Reviewed-by: Fangrui Song
Thanks. I'll reword the commit message to include a reference to that
change. It's also not just 64-bit, on 32-bit it currently fails before
it gets around to linking setup.elf due to the text relocs issues,
that's why this one doesn't show up, but they are in fact at least
consistent.
Re: [PATCH 0/1] x86/boot: lld fix
On 2020-05-20, Arvind Sankar wrote:
On Wed, May 20, 2020 at 06:56:53PM -0400, Arvind Sankar wrote:
arch/x86/boot/setup.elf currently has an orphan section .text.startup,
and lld git as of ebf14d9b6d8b is breaking on 64-bit due to what seems
to be a change in behavior on orphan section placement (details in patch
commit message).
I'm not sure if this was an intentional change in lld, but it seems like
a good idea to explicitly include .text.startup anyway.
Arvind Sankar (1):
x86/boot: Add .text.startup to setup.ld
arch/x86/boot/setup.ld | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--
2.26.2
I found your PATCH 1/1 on https://lkml.org/lkml/2020/5/20/1491
- .text : { *(.text) }
+ .text : { *(.text.startup) *(.text) }
The LLD behavior change was introduced in
https://reviews.llvm.org/D75225 (will be included in 11.0.0)
It was intended to match GNU ld.
But yes, orphan section placement is still different in the two linkers.
Placing .text.startup before .text seems good.
In GNU ld's internal linker script (ld --verbose),
.text.startup is placed before .text
Reviewed-by: Fangrui Song
Re: [PATCH 0/1] x86/boot: lld fix
On Wed, May 20, 2020 at 06:56:53PM -0400, Arvind Sankar wrote: > arch/x86/boot/setup.elf currently has an orphan section .text.startup, > and lld git as of ebf14d9b6d8b is breaking on 64-bit due to what seems > to be a change in behavior on orphan section placement (details in patch > commit message). > > I'm not sure if this was an intentional change in lld, but it seems like > a good idea to explicitly include .text.startup anyway. > > Arvind Sankar (1): > x86/boot: Add .text.startup to setup.ld > > arch/x86/boot/setup.ld | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > -- > 2.26.2 > Actually I'm not sure this is a recent change. I updated to the git tip because on my system (gentoo with gcc-10), lld-10.0.0 segfaults when trying to link the compressed kernel, and updating to lld git fixed that. So I previously probably didn't get to the stage where it links setup.elf.
[PATCH 0/1] x86/boot: lld fix
arch/x86/boot/setup.elf currently has an orphan section .text.startup, and lld git as of ebf14d9b6d8b is breaking on 64-bit due to what seems to be a change in behavior on orphan section placement (details in patch commit message). I'm not sure if this was an intentional change in lld, but it seems like a good idea to explicitly include .text.startup anyway. Arvind Sankar (1): x86/boot: Add .text.startup to setup.ld arch/x86/boot/setup.ld | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.26.2
