From: Nathan Chancellor <nathan@kernel.org>
To: Paul Cercueil <paul@crapouillou.net>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Nick Desaulniers <ndesaulniers@google.com>,
list@opendingux.net, linux-mips@vger.kernel.org,
linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [PATCH 2/3] MIPS: boot/compressed: Build without LTO
Date: Tue, 14 Dec 2021 11:07:21 -0700 [thread overview]
Message-ID: <YbjdWe+i6wQduHEq@archlinux-ax161> (raw)
In-Reply-To: <20211213224914.1501303-3-paul@crapouillou.net>
On Mon, Dec 13, 2021 at 10:49:13PM +0000, Paul Cercueil wrote:
> We need a valid ELF object for dummy.o, so that objcopy can insert the
> vmlinuz payload.
>
> Therefore, we must build the decompresser program without LTO, otherwise
> dummy.o will be LLVM bytecode instead of a ELF object file.
>
> Building the decompresser with LTO wouldn't make much sense anyway,
> unlike building the vmlinuz itself with LTO.
>
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Seems reasonable.
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
> ---
> arch/mips/boot/compressed/Makefile | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
> index 4c9ecfbb0ef4..2d01c50fb0b1 100644
> --- a/arch/mips/boot/compressed/Makefile
> +++ b/arch/mips/boot/compressed/Makefile
> @@ -27,6 +27,9 @@ ifdef CONFIG_CPU_LOONGSON64
> KBUILD_CFLAGS := $(filter-out -march=loongson3a, $(KBUILD_CFLAGS)) -march=mips64r2
> endif
>
> +# Disable LTO
> +KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_LTO), $(KBUILD_CFLAGS))
> +
> KBUILD_CFLAGS := $(KBUILD_CFLAGS) -mno-abicalls -D__KERNEL__ -D__DISABLE_EXPORTS \
> -DBOOT_HEAP_SIZE=$(BOOT_HEAP_SIZE) -D"VMLINUX_LOAD_ADDRESS_ULL=$(VMLINUX_LOAD_ADDRESS)ull"
>
> --
> 2.33.0
>
>
next prev parent reply other threads:[~2021-12-14 18:07 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-13 22:49 [PATCH 0/3] MIPS: Add support for LTO Paul Cercueil
2021-12-13 22:49 ` [PATCH 1/3] MIPS: boot/compressed: Disable abicalls Paul Cercueil
2021-12-14 18:06 ` Nathan Chancellor
2021-12-14 19:09 ` Paul Cercueil
2021-12-14 19:38 ` Nick Desaulniers
2021-12-13 22:49 ` [PATCH 2/3] MIPS: boot/compressed: Build without LTO Paul Cercueil
2021-12-14 18:07 ` Nathan Chancellor [this message]
2021-12-14 19:43 ` Nick Desaulniers
2021-12-13 22:49 ` [PATCH 3/3] MIPS: Add support for LTO Paul Cercueil
2021-12-14 18:09 ` Nathan Chancellor
2021-12-14 19:45 ` Nick Desaulniers
2021-12-14 18:11 ` [PATCH 0/3] " Nathan Chancellor
2021-12-14 19:34 ` Nick Desaulniers
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