On Fri, Feb 18, 2022 at 12:50:16AM -0800, Fangrui Song wrote:

On 2022-02-18, Ard Biesheuvel wrote:

quoted

On Fri, 18 Feb 2022 at 09:12, Fangrui Song [off-list ref] wrote:

quoted

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outdated for ELF.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 <redacted>
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>

quoted

quoted

---
 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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