linux-kernel - Re: x86/build: Move max-page-size option to LDFLAGS

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Date:   Thu, 23 Jul 2020 18:00:50 +0200
From:   Sedat Dilek <sedat.dilek@...il.com>
To:     Arvind Sankar <nivedita@...m.mit.edu>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: x86/build: Move max-page-size option to LDFLAGS_vmlinux

[ Please CC me I am not subscribed to this ML ]

[1] says:
"
This option is only required for vmlinux on 64-bit, to enforce 2MiB
alignment, so set it in LDFLAGS_vmlinux instead of KBUILD_LDFLAGS. Also
drop the ld-option check: this option was added in binutils-2.18 and all
the other places that use it already don't have the check.

This reduces the size of the intermediate ELF files
arch/x86/boot/setup.elf and arch/x86/realmode/rm/realmode.elf by about
2MiB each. The binary versions are unchanged.

Move the LDFLAGS settings to all be together and just after CFLAGS
settings are done.

Signed-off-by: Arvind Sankar <nivedita@...m.mit.edu>
"

Hi Arvind,

I have tested this on top of Linux v5.8-rc6 with a snapshot version of
LLVM/Clang/LLD v11.

Without your patch:
$ grep "max-page-size=0x200000"
build-log_5.8.0-rc6-4-amd64-llvm11-ias.txt | wc -l
16935

With your patch:
$ grep "max-page-size=0x200000"
build-log_5.8.0-rc6-6-amd64-llvm11-ias.txt | wc -l
4

I was able to build and boot on a Debian AMD64 system.

Feel free to add:

   Tested-by: Sedat Dilek <sedat.dilek@...il.com>

Regards,
- Sedat -

[1] https://lore.kernel.org/patchwork/patch/1277806/