From: "Maciej W. Rozycki" <macro@linux-mips.org>
To: Fangrui Song <maskray@google.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>,
linux-mips@vger.kernel.org, clang-built-linux@googlegroups.com,
Nathan Chancellor <natechancellor@gmail.com>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Borislav Petkov <bp@suse.de>, Kees Cook <keescook@chromium.org>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4] MIPS: Truncate link address into 32bit for 32bit kernel
Date: Mon, 13 Apr 2020 21:08:46 +0100 (BST) [thread overview]
Message-ID: <alpine.LFD.2.21.2004132107550.851719@eddie.linux-mips.org> (raw)
In-Reply-To: <20200413153453.zi4jvu3c4ul23e23@google.com>
On Mon, 13 Apr 2020, Fangrui Song wrote:
> >> > diff --git a/arch/mips/kernel/vmlinux.lds.S
> >> > b/arch/mips/kernel/vmlinux.lds.S index a5f00ec73ea6..5226cd8e4bee
> >> > 100644 --- a/arch/mips/kernel/vmlinux.lds.S
> >> > +++ b/arch/mips/kernel/vmlinux.lds.S
> >> > @@ -55,7 +55,7 @@ SECTIONS
> >> > /* . = 0xa800000000300000; */
> >> > . = 0xffffffff80300000;
> >> > #endif
> >> > - . = VMLINUX_LOAD_ADDRESS;
> >> > + . = VMLINUX_LINK_ADDRESS;
> >>
> >> The CONFIG_BOOT_ELF64 cruft right above it looks interesting to me,
> >> never have ever been used. We have had the current arrangement since:
> >
> >It confused me either.
> >It's only used by SGI so probably it's time to rename it as
> >BOOT_SEG_ELF64.
> >
> >Wish someone could clarify what is it.
> >
> >Thanks.
>
> Agreed that -Ttext in
>
> arch/mips/boot/compressed/Makefile
> 100: cmd_zld = $(LD) $(KBUILD_LDFLAGS) -Ttext $(VMLINUZ_LOAD_ADDRESS) -T
> $< $(vmlinuzobjs-y) -o $@
>
> and a few other places are brittle. They need to be replaced with Output
> Section Address:
> (https://sourceware.org/binutils/docs/ld/Output-Section-Address.html
> https://github.com/llvm/llvm-project/blob/master/lld/docs/ELF/linker_script.rst#output-section-address)
>
> -Ttext changes the address of .text . This can lead to the change of the
> address of the text segment (RX), but this is not guaranteed (many
> sections can be placed before .text and they are not affected).
That is unrelated, but you're free to clean it up of course.
Maciej
next prev parent reply other threads:[~2020-05-13 22:23 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-13 6:26 [PATCH v4] MIPS: Truncate link address into 32bit for 32bit kernel Jiaxun Yang
2020-04-13 6:59 ` Maciej W. Rozycki
2020-04-13 7:32 ` Jiaxun Yang
2020-04-13 15:34 ` Fangrui Song
2020-04-13 20:08 ` Maciej W. Rozycki [this message]
2020-04-13 20:06 ` Maciej W. Rozycki
2020-04-13 16:25 ` Kees Cook
2020-04-13 18:52 ` Nathan Chancellor
2020-04-22 14:32 ` [PATCH v5] " Jiaxun Yang
2020-04-22 22:16 ` Nathan Chancellor
2020-04-23 0:10 ` Maciej W. Rozycki
2020-04-23 5:42 ` Jiaxun Yang
2020-04-24 12:22 ` Maciej W. Rozycki
2020-05-04 15:46 ` Thomas Bogendoerfer
2020-05-04 16:09 ` Jiaxun Yang
2020-05-04 16:56 ` Thomas Bogendoerfer
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