* [PATCH] arm64 module: remove (NOLOAD)
@ 2022-02-18 8:12 Fangrui Song
2022-02-18 8:17 ` Ard Biesheuvel
2022-02-25 15:50 ` Will Deacon
0 siblings, 2 replies; 6+ messages in thread
From: Fangrui Song @ 2022-02-18 8:12 UTC (permalink / raw)
To: Catalin Marinas, Will Deacon, Ard Biesheuvel, linux-arm-kernel
Cc: Nathan Chancellor, linux-kernel, llvm, Fangrui Song
On ELF, (NOLOAD) sets the section type to SHT_NOBITS[1]. It is conceptually
inappropriate for .plt and .text.* sections which are always
SHT_PROGBITS.
In GNU ld, if PLT entries are needed, .plt will be SHT_PROGBITS anyway
and (NOLOAD) will be essentially ignored. In ld.lld, since
https://reviews.llvm.org/D118840 ("[ELF] Support (TYPE=<value>) to
customize the output section type"), ld.lld will report a `section type
mismatch` error. Just remove (NOLOAD) to fix the error.
[1] https://lld.llvm.org/ELF/linker_script.html As of today, "The
section should be marked as not loadable" on
https://sourceware.org/binutils/docs/ld/Output-Section-Type.html is
outdated for ELF.
---
arch/arm64/include/asm/module.lds.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/module.lds.h b/arch/arm64/include/asm/module.lds.h
index a11ccadd47d2..094701ec5500 100644
--- a/arch/arm64/include/asm/module.lds.h
+++ b/arch/arm64/include/asm/module.lds.h
@@ -1,8 +1,8 @@
SECTIONS {
#ifdef CONFIG_ARM64_MODULE_PLTS
- .plt 0 (NOLOAD) : { BYTE(0) }
- .init.plt 0 (NOLOAD) : { BYTE(0) }
- .text.ftrace_trampoline 0 (NOLOAD) : { BYTE(0) }
+ .plt 0 : { BYTE(0) }
+ .init.plt 0 : { BYTE(0) }
+ .text.ftrace_trampoline 0 : { BYTE(0) }
#endif
#ifdef CONFIG_KASAN_SW_TAGS
--
2.35.1.265.g69c8d7142f-goog
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^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] arm64 module: remove (NOLOAD) 2022-02-18 8:12 [PATCH] arm64 module: remove (NOLOAD) Fangrui Song @ 2022-02-18 8:17 ` Ard Biesheuvel 2022-02-18 8:50 ` Fangrui Song 2022-02-25 15:50 ` Will Deacon 1 sibling, 1 reply; 6+ messages in thread From: Ard Biesheuvel @ 2022-02-18 8:17 UTC (permalink / raw) To: Fangrui Song Cc: Catalin Marinas, Will Deacon, Linux ARM, Nathan Chancellor, Linux Kernel Mailing List, llvm On Fri, 18 Feb 2022 at 09:12, Fangrui Song <maskray@google.com> wrote: > > On ELF, (NOLOAD) sets the section type to SHT_NOBITS[1]. It is conceptually > inappropriate for .plt and .text.* sections which are always > SHT_PROGBITS. > > In GNU ld, if PLT entries are needed, .plt will be SHT_PROGBITS anyway > and (NOLOAD) will be essentially ignored. In ld.lld, since > https://reviews.llvm.org/D118840 ("[ELF] Support (TYPE=<value>) to > customize the output section type"), ld.lld will report a `section type > mismatch` error. Just remove (NOLOAD) to fix the error. > > [1] https://lld.llvm.org/ELF/linker_script.html As of today, "The > section should be marked as not loadable" on > https://sourceware.org/binutils/docs/ld/Output-Section-Type.html is > outdated for ELF. This patch lacks a SOB line. With one added, Acked-by: Ard Biesheuvel <ardb@kernel.org> > --- > arch/arm64/include/asm/module.lds.h | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/include/asm/module.lds.h b/arch/arm64/include/asm/module.lds.h > index a11ccadd47d2..094701ec5500 100644 > --- a/arch/arm64/include/asm/module.lds.h > +++ b/arch/arm64/include/asm/module.lds.h > @@ -1,8 +1,8 @@ > SECTIONS { > #ifdef CONFIG_ARM64_MODULE_PLTS > - .plt 0 (NOLOAD) : { BYTE(0) } > - .init.plt 0 (NOLOAD) : { BYTE(0) } > - .text.ftrace_trampoline 0 (NOLOAD) : { BYTE(0) } > + .plt 0 : { BYTE(0) } > + .init.plt 0 : { BYTE(0) } > + .text.ftrace_trampoline 0 : { BYTE(0) } > #endif > > #ifdef CONFIG_KASAN_SW_TAGS > -- > 2.35.1.265.g69c8d7142f-goog > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] arm64 module: remove (NOLOAD) 2022-02-18 8:17 ` Ard Biesheuvel @ 2022-02-18 8:50 ` Fangrui Song 2022-02-18 16:34 ` Nathan Chancellor 0 siblings, 1 reply; 6+ messages in thread From: Fangrui Song @ 2022-02-18 8:50 UTC (permalink / raw) To: Ard Biesheuvel Cc: Catalin Marinas, Will Deacon, Linux ARM, Nathan Chancellor, Linux Kernel Mailing List, llvm On 2022-02-18, Ard Biesheuvel wrote: >On Fri, 18 Feb 2022 at 09:12, Fangrui Song <maskray@google.com> wrote: >> >> On ELF, (NOLOAD) sets the section type to SHT_NOBITS[1]. It is conceptually >> inappropriate for .plt and .text.* sections which are always >> SHT_PROGBITS. >> >> In GNU ld, if PLT entries are needed, .plt will be SHT_PROGBITS anyway >> and (NOLOAD) will be essentially ignored. In ld.lld, since >> https://reviews.llvm.org/D118840 ("[ELF] Support (TYPE=<value>) to >> customize the output section type"), ld.lld will report a `section type >> mismatch` error. Just remove (NOLOAD) to fix the error. >> >> [1] https://lld.llvm.org/ELF/linker_script.html As of today, "The >> section should be marked as not loadable" on >> https://sourceware.org/binutils/docs/ld/Output-Section-Type.html is >> outdated for ELF. > >This patch lacks a SOB line. > >With one added, > >Acked-by: Ard Biesheuvel <ardb@kernel.org> Ah, yes. Sorry, I haven't sent a kernel patch for a while... Reported-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Fangrui Song <maskray@google.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> >> --- >> arch/arm64/include/asm/module.lds.h | 6 +++--- >> 1 file changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/arch/arm64/include/asm/module.lds.h b/arch/arm64/include/asm/module.lds.h >> index a11ccadd47d2..094701ec5500 100644 >> --- a/arch/arm64/include/asm/module.lds.h >> +++ b/arch/arm64/include/asm/module.lds.h >> @@ -1,8 +1,8 @@ >> SECTIONS { >> #ifdef CONFIG_ARM64_MODULE_PLTS >> - .plt 0 (NOLOAD) : { BYTE(0) } >> - .init.plt 0 (NOLOAD) : { BYTE(0) } >> - .text.ftrace_trampoline 0 (NOLOAD) : { BYTE(0) } >> + .plt 0 : { BYTE(0) } >> + .init.plt 0 : { BYTE(0) } >> + .text.ftrace_trampoline 0 : { BYTE(0) } >> #endif >> >> #ifdef CONFIG_KASAN_SW_TAGS >> -- >> 2.35.1.265.g69c8d7142f-goog >> _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] arm64 module: remove (NOLOAD) 2022-02-18 8:50 ` Fangrui Song @ 2022-02-18 16:34 ` Nathan Chancellor 2022-02-18 19:08 ` Ard Biesheuvel 0 siblings, 1 reply; 6+ messages in thread From: Nathan Chancellor @ 2022-02-18 16:34 UTC (permalink / raw) To: Fangrui Song Cc: Ard Biesheuvel, Catalin Marinas, Will Deacon, Linux ARM, Linux Kernel Mailing List, llvm On Fri, Feb 18, 2022 at 12:50:16AM -0800, Fangrui Song wrote: > On 2022-02-18, Ard Biesheuvel wrote: > > On Fri, 18 Feb 2022 at 09:12, Fangrui Song <maskray@google.com> wrote: > > > > > > On ELF, (NOLOAD) sets the section type to SHT_NOBITS[1]. It is conceptually > > > inappropriate for .plt and .text.* sections which are always > > > SHT_PROGBITS. > > > > > > In GNU ld, if PLT entries are needed, .plt will be SHT_PROGBITS anyway > > > and (NOLOAD) will be essentially ignored. In ld.lld, since > > > https://reviews.llvm.org/D118840 ("[ELF] Support (TYPE=<value>) to > > > customize the output section type"), ld.lld will report a `section type > > > mismatch` error. Just remove (NOLOAD) to fix the error. > > > > > > [1] https://lld.llvm.org/ELF/linker_script.html As of today, "The > > > section should be marked as not loadable" on > > > https://sourceware.org/binutils/docs/ld/Output-Section-Type.html is > > > outdated for ELF. > > > > This patch lacks a SOB line. > > > > With one added, > > > > Acked-by: Ard Biesheuvel <ardb@kernel.org> > > Ah, yes. Sorry, I haven't sent a kernel patch for a while... > > Reported-by: Nathan Chancellor <nathan@kernel.org> > Signed-off-by: Fangrui Song <maskray@google.com> > Acked-by: Ard Biesheuvel <ardb@kernel.org> I am assuming this patch is the solution we want, as opposed to Ard's suggestion of renaming these sections at https://reviews.llvm.org/D118840 (unless that was a tangential suggestion). I have verified that modules still load. Additionally, this needs to go to stable so that groups who upgrade their toolchain to a revision that include the LLD patch don't get broken as well. Cc: stable@vger.kernel.org Tested-by: Nathan Chancellor <nathan@kernel.org> > > > --- > > > arch/arm64/include/asm/module.lds.h | 6 +++--- > > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > > > diff --git a/arch/arm64/include/asm/module.lds.h b/arch/arm64/include/asm/module.lds.h > > > index a11ccadd47d2..094701ec5500 100644 > > > --- a/arch/arm64/include/asm/module.lds.h > > > +++ b/arch/arm64/include/asm/module.lds.h > > > @@ -1,8 +1,8 @@ > > > SECTIONS { > > > #ifdef CONFIG_ARM64_MODULE_PLTS > > > - .plt 0 (NOLOAD) : { BYTE(0) } > > > - .init.plt 0 (NOLOAD) : { BYTE(0) } > > > - .text.ftrace_trampoline 0 (NOLOAD) : { BYTE(0) } > > > + .plt 0 : { BYTE(0) } > > > + .init.plt 0 : { BYTE(0) } > > > + .text.ftrace_trampoline 0 : { BYTE(0) } > > > #endif > > > > > > #ifdef CONFIG_KASAN_SW_TAGS > > > -- > > > 2.35.1.265.g69c8d7142f-goog > > > > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] arm64 module: remove (NOLOAD) 2022-02-18 16:34 ` Nathan Chancellor @ 2022-02-18 19:08 ` Ard Biesheuvel 0 siblings, 0 replies; 6+ messages in thread From: Ard Biesheuvel @ 2022-02-18 19:08 UTC (permalink / raw) To: Nathan Chancellor Cc: Fangrui Song, Catalin Marinas, Will Deacon, Linux ARM, Linux Kernel Mailing List, llvm On Fri, 18 Feb 2022 at 17:34, Nathan Chancellor <nathan@kernel.org> wrote: > > On Fri, Feb 18, 2022 at 12:50:16AM -0800, Fangrui Song wrote: > > On 2022-02-18, Ard Biesheuvel wrote: > > > On Fri, 18 Feb 2022 at 09:12, Fangrui Song <maskray@google.com> wrote: > > > > > > > > On ELF, (NOLOAD) sets the section type to SHT_NOBITS[1]. It is conceptually > > > > inappropriate for .plt and .text.* sections which are always > > > > SHT_PROGBITS. > > > > > > > > In GNU ld, if PLT entries are needed, .plt will be SHT_PROGBITS anyway > > > > and (NOLOAD) will be essentially ignored. In ld.lld, since > > > > https://reviews.llvm.org/D118840 ("[ELF] Support (TYPE=<value>) to > > > > customize the output section type"), ld.lld will report a `section type > > > > mismatch` error. Just remove (NOLOAD) to fix the error. > > > > > > > > [1] https://lld.llvm.org/ELF/linker_script.html As of today, "The > > > > section should be marked as not loadable" on > > > > https://sourceware.org/binutils/docs/ld/Output-Section-Type.html is > > > > outdated for ELF. > > > > > > This patch lacks a SOB line. > > > > > > With one added, > > > > > > Acked-by: Ard Biesheuvel <ardb@kernel.org> > > > > Ah, yes. Sorry, I haven't sent a kernel patch for a while... > > > > Reported-by: Nathan Chancellor <nathan@kernel.org> > > Signed-off-by: Fangrui Song <maskray@google.com> > > Acked-by: Ard Biesheuvel <ardb@kernel.org> > > I am assuming this patch is the solution we want, as opposed to Ard's > suggestion of renaming these sections at > https://reviews.llvm.org/D118840 (unless that was a tangential > suggestion). > Renaming will not make the problem go away. It will only clear up the confusion regarding the contents of these sections, which are not in fact linker emitted PLT entries, but branching veneers emitted by the kernel's module loader. > I have verified that modules still load. Additionally, this needs to go > to stable so that groups who upgrade their toolchain to a revision that > include the LLD patch don't get broken as well. > > Cc: stable@vger.kernel.org > Tested-by: Nathan Chancellor <nathan@kernel.org> > > > > > > --- > > > > arch/arm64/include/asm/module.lds.h | 6 +++--- > > > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > > > > > diff --git a/arch/arm64/include/asm/module.lds.h b/arch/arm64/include/asm/module.lds.h > > > > index a11ccadd47d2..094701ec5500 100644 > > > > --- a/arch/arm64/include/asm/module.lds.h > > > > +++ b/arch/arm64/include/asm/module.lds.h > > > > @@ -1,8 +1,8 @@ > > > > SECTIONS { > > > > #ifdef CONFIG_ARM64_MODULE_PLTS > > > > - .plt 0 (NOLOAD) : { BYTE(0) } > > > > - .init.plt 0 (NOLOAD) : { BYTE(0) } > > > > - .text.ftrace_trampoline 0 (NOLOAD) : { BYTE(0) } > > > > + .plt 0 : { BYTE(0) } > > > > + .init.plt 0 : { BYTE(0) } > > > > + .text.ftrace_trampoline 0 : { BYTE(0) } > > > > #endif > > > > > > > > #ifdef CONFIG_KASAN_SW_TAGS > > > > -- > > > > 2.35.1.265.g69c8d7142f-goog > > > > > > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] arm64 module: remove (NOLOAD) 2022-02-18 8:12 [PATCH] arm64 module: remove (NOLOAD) Fangrui Song 2022-02-18 8:17 ` Ard Biesheuvel @ 2022-02-25 15:50 ` Will Deacon 1 sibling, 0 replies; 6+ messages in thread From: Will Deacon @ 2022-02-25 15:50 UTC (permalink / raw) To: Fangrui Song, linux-arm-kernel, Ard Biesheuvel, Catalin Marinas Cc: kernel-team, Will Deacon, linux-kernel, Nathan Chancellor, llvm On Fri, 18 Feb 2022 00:12:09 -0800, Fangrui Song wrote: > On ELF, (NOLOAD) sets the section type to SHT_NOBITS[1]. It is conceptually > inappropriate for .plt and .text.* sections which are always > SHT_PROGBITS. > > In GNU ld, if PLT entries are needed, .plt will be SHT_PROGBITS anyway > and (NOLOAD) will be essentially ignored. In ld.lld, since > https://reviews.llvm.org/D118840 ("[ELF] Support (TYPE=<value>) to > customize the output section type"), ld.lld will report a `section type > mismatch` error. Just remove (NOLOAD) to fix the error. > > [...] Applied to arm64 (for-next/linkage), thanks! [1/1] arm64: module: remove (NOLOAD) from linker script https://git.kernel.org/arm64/c/4013e26670c5 Cheers, -- Will https://fixes.arm64.dev https://next.arm64.dev https://will.arm64.dev _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-02-25 15:53 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2022-02-18 8:12 [PATCH] arm64 module: remove (NOLOAD) Fangrui Song 2022-02-18 8:17 ` Ard Biesheuvel 2022-02-18 8:50 ` Fangrui Song 2022-02-18 16:34 ` Nathan Chancellor 2022-02-18 19:08 ` Ard Biesheuvel 2022-02-25 15:50 ` Will Deacon
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