Messages in this thread Patch in this message | | | Date | Wed, 14 Feb 2024 13:29:29 -0800 | Subject | [PATCH] x86/build: Simplify patterns for unwanted section | From | Fangrui Song <> |
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A s390 patch modeling its --orphan-handling= after x86 [1] sparked my motivation to simplify patterns. Commit 5354e84598f2 ("x86/build: Add asserts for unwanted sections") added asserts that certain input sections must be absent or empty. The patterns can be simplified.
For dynamic relocations,
*(.rela.*) is sufficient to match all dynamic relocations synthesized by GNU ld and LLD. .rela_* is unnecessary. --emit-relocs may create .rela_* sections for section names prefixed with _, but they are not matched by linker scripts.
plt instead of .plt.* is sufficient to match synthesized PLT entries.
igot and .igot.plt are for non-preemptible STT_GNU_IFUNC in GNU ld (LLD just uses .got), which the kernel does not use. In addition, if .igot or igot.plt is ever non-empty, there will be .rela.* dynamic relocations leading to an assert failure anyway.
[1]: https://lore.kernel.org/all/20240207-s390-lld-and-orphan-warn-v1-6-8a665b3346ab@kernel.org/
Signed-off-by: Fangrui Song <maskray@google.com> --- arch/x86/boot/compressed/vmlinux.lds.S | 6 +++--- arch/x86/kernel/vmlinux.lds.S | 8 ++++---- 2 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/arch/x86/boot/compressed/vmlinux.lds.S b/arch/x86/boot/compressed/vmlinux.lds.S index 083ec6d7722a..9f288f67972a 100644 --- a/arch/x86/boot/compressed/vmlinux.lds.S +++ b/arch/x86/boot/compressed/vmlinux.lds.S @@ -104,17 +104,17 @@ SECTIONS ASSERT(SIZEOF(.got) == 0, "Unexpected GOT entries detected!") .plt : { - *(.plt) *(.plt.*) + *(.plt) } ASSERT(SIZEOF(.plt) == 0, "Unexpected run-time procedure linkages detected!") .rel.dyn : { - *(.rel.*) *(.rel_*) + *(.rel.*) } ASSERT(SIZEOF(.rel.dyn) == 0, "Unexpected run-time relocations (.rel) detected!") .rela.dyn : { - *(.rela.*) *(.rela_*) + *(.rela.*) } ASSERT(SIZEOF(.rela.dyn) == 0, "Unexpected run-time relocations (.rela) detected!") } diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index a349dbfc6d5a..b3da7b81d2b3 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -463,22 +463,22 @@ SECTIONS * explicitly check instead of blindly discarding. */ .got : { - *(.got) *(.igot.*) + *(.got) } ASSERT(SIZEOF(.got) == 0, "Unexpected GOT entries detected!") .plt : { - *(.plt) *(.plt.*) *(.iplt) + *(.plt) } ASSERT(SIZEOF(.plt) == 0, "Unexpected run-time procedure linkages detected!") .rel.dyn : { - *(.rel.*) *(.rel_*) + *(.rel.*) } ASSERT(SIZEOF(.rel.dyn) == 0, "Unexpected run-time relocations (.rel) detected!") .rela.dyn : { - *(.rela.*) *(.rela_*) + *(.rela.*) } ASSERT(SIZEOF(.rela.dyn) == 0, "Unexpected run-time relocations (.rela) detected!") } -- 2.43.0.687.g38aa6559b0-goog
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