[PATCH v9 05/16] kbuild: lto: merge module sections
From: Sami Tolvanen <samitolvanen@google.com>
Date: 2020-12-11 20:31:40
Also in:
linux-arch, linux-kbuild, linux-pci, lkml
Subsystem:
module support, the rest · Maintainers:
Luis Chamberlain, Petr Pavlu, Daniel Gomez, Sami Tolvanen, Linus Torvalds
LLD always splits sections with LTO, which increases module sizes. This change adds linker script rules to merge the split sections in the final module. Suggested-by: Nick Desaulniers <redacted> Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <redacted> --- scripts/module.lds.S | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)
diff --git a/scripts/module.lds.S b/scripts/module.lds.S
index 69b9b71a6a47..18d5b8423635 100644
--- a/scripts/module.lds.S
+++ b/scripts/module.lds.S@@ -23,6 +23,30 @@ SECTIONS { .init_array 0 : ALIGN(8) { *(SORT(.init_array.*)) *(.init_array) } __jump_table 0 : ALIGN(8) { KEEP(*(__jump_table)) } + + __patchable_function_entries : { *(__patchable_function_entries) } + + /* + * With CONFIG_LTO_CLANG, LLD always enables -fdata-sections and + * -ffunction-sections, which increases the size of the final module. + * Merge the split sections in the final binary. + */ + .bss : { + *(.bss .bss.[0-9a-zA-Z_]*) + *(.bss..L*) + } + + .data : { + *(.data .data.[0-9a-zA-Z_]*) + *(.data..L*) + } + + .rodata : { + *(.rodata .rodata.[0-9a-zA-Z_]*) + *(.rodata..L*) + } + + .text : { *(.text .text.[0-9a-zA-Z_]*) } } /* bring in arch-specific sections */
--
2.29.2.576.ga3fc446d84-goog
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