Trying to make a working kernel with the gold linker

Trying to make a working kernel with the gold linker

[Theodore Ts'o]

So I was trying to see if I could make the kernel build with the gold
linker (since until it can, I can't install it on my system).

I saw a message from HJ indicating one of the problems was x86_64 gold
used an incompatible max-page-size setting, so I tried changing it in
hopes that would make a bootable kernel.

No dice, it didn't work.  (At least not with a 2.20 binutils-gold.)

Does anybody know what the other issues with the gold linker?  Is the
2.22 binutils-gold more likely to work?

Thanks,

					- Ted


diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 41a7237..ad769ed 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -119,7 +119,11 @@ asinstr := $(call as-instr,fxsaveq (%rax),-DCONFIG_AS_FXSAVEQ=1)
 KBUILD_AFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr)
 KBUILD_CFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr)
 
+ifeq ($(CONFIG_X86_32),y)
 LDFLAGS := -m elf_$(UTS_MACHINE)
+else
+LDFLAGS := -m elf_$(UTS_MACHINE) -z max-page-size=0x200000
+endif
 
 # Speed up the build
 KBUILD_CFLAGS += -pipe

Re: Trying to make a working kernel with the gold linker

[H. Peter Anvin]

On 04/10/2012 07:23 PM, Theodore Ts'o wrote:
> So I was trying to see if I could make the kernel build with the gold
> linker (since until it can, I can't install it on my system).
> 
> I saw a message from HJ indicating one of the problems was x86_64 gold
> used an incompatible max-page-size setting, so I tried changing it in
> hopes that would make a bootable kernel.
> 
> No dice, it didn't work.  (At least not with a 2.20 binutils-gold.)
> 
> Does anybody know what the other issues with the gold linker?  Is the
> 2.22 binutils-gold more likely to work?

It would also be kind of nice if the ELF image generated for the kernel
didn't contain several megabytes of zero that serve no purpose and have
to be decompressed at boot time...

	-hpa

Re: Trying to make a working kernel with the gold linker

[Markus Trippelsdorf]

On 2012.04.10 at 22:23 -0400, Theodore Ts'o wrote:
> 
> So I was trying to see if I could make the kernel build with the gold
> linker (since until it can, I can't install it on my system).
> 
> I saw a message from HJ indicating one of the problems was x86_64 gold
> used an incompatible max-page-size setting, so I tried changing it in
> hopes that would make a bootable kernel.
> 
> No dice, it didn't work.  (At least not with a 2.20 binutils-gold.)
> 
> Does anybody know what the other issues with the gold linker?  Is the
> 2.22 binutils-gold more likely to work?

Yes. I use it regularly. The last problems were fixed two years ago.
Please try a more recent version.

-- 
Markus

Re: Trying to make a working kernel with the gold linker

[Ted Ts'o]

On Wed, Apr 11, 2012 at 06:51:07AM +0200, Markus Trippelsdorf wrote:
> 
> Yes. I use it regularly. The last problems were fixed two years ago.
> Please try a more recent version.

Thanks, I'll give that a try.  Next stupid question; for a variety of
reasons, the Corporate I/T folks require that I stay stuck on Ubuntu
10.04.  Are there any incompatibility problems with using the most
recently released binutils-gold and gcc 4.4.3-4ubuntu5.1?  Basically,
can I just compile a new version of binutils, or do I need to upgrade
my entire compiler toolchain?

Thanks,

						- Ted

Re: Trying to make a working kernel with the gold linker

[Markus Trippelsdorf]

On 2012.04.11 at 14:05 -0400, Ted Ts'o wrote:
> On Wed, Apr 11, 2012 at 06:51:07AM +0200, Markus Trippelsdorf wrote:
> > 
> > Yes. I use it regularly. The last problems were fixed two years ago.
> > Please try a more recent version.
> 
> Thanks, I'll give that a try.  Next stupid question; for a variety of
> reasons, the Corporate I/T folks require that I stay stuck on Ubuntu
> 10.04.  Are there any incompatibility problems with using the most
> recently released binutils-gold and gcc 4.4.3-4ubuntu5.1?  Basically,
> can I just compile a new version of binutils, or do I need to upgrade
> my entire compiler toolchain?

Just compiling and installing a new binutils version should work fine.

(But you should nonetheless consider to also upgrade gcc, because
gcc-4.4 is ancient and not even officially maintained anymore...)

-- 
Markus

Re: Trying to make a working kernel with the gold linker

[Ted Ts'o]

On Wed, Apr 11, 2012 at 08:28:56PM +0200, Markus Trippelsdorf wrote:
> 
> Just compiling and installing a new binutils version should work fine.
> 
> (But you should nonetheless consider to also upgrade gcc, because
> gcc-4.4 is ancient and not even officially maintained anymore...)

Well *someone* has to still make sure the kernel compiles correctly on
the enterprise distro's that a huge number of Linux users use...
(including RHEL 6, Debian Stable, SLES 11, Ubuntu LTS 10.04, etc.)

:-)

But yeah, I hope to get off of Ubuntu LTS real soon now, and onto
something a bit more hip, such as Debian testing.

						- Ted

Re: Trying to make a working kernel with the gold linker

[H.J. Lu]

On Wed, Apr 11, 2012 at 12:13 PM, Ted Ts'o <tytso@mit.edu> wrote:
> On Wed, Apr 11, 2012 at 08:28:56PM +0200, Markus Trippelsdorf wrote:
>>
>> Just compiling and installing a new binutils version should work fine.
>>
>> (But you should nonetheless consider to also upgrade gcc, because
>> gcc-4.4 is ancient and not even officially maintained anymore...)
>
> Well *someone* has to still make sure the kernel compiles correctly on
> the enterprise distro's that a huge number of Linux users use...
> (including RHEL 6, Debian Stable, SLES 11, Ubuntu LTS 10.04, etc.)
>
> :-)
>
> But yeah, I hope to get off of Ubuntu LTS real soon now, and onto
> something a bit more hip, such as Debian testing.
>
>                                                - Ted

To build Linux kernel with gold, you should at least try gold in
binutils 2.22.

-- 
H.J.