Messages in this thread Patch in this message | | | Date | Fri, 18 Sep 2020 13:14:21 -0700 | Subject | [PATCH v3 15/30] kbuild: lto: merge module sections | From | Sami Tolvanen <> |
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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 <ndesaulniers@google.com> Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> --- scripts/module.lds.S | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+)
diff --git a/scripts/module.lds.S b/scripts/module.lds.S index 69b9b71a6a47..037120173a22 100644 --- a/scripts/module.lds.S +++ b/scripts/module.lds.S @@ -25,5 +25,33 @@ SECTIONS { __jump_table 0 : ALIGN(8) { KEEP(*(__jump_table)) } } +#ifdef CONFIG_LTO_CLANG +/* + * 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. + */ +SECTIONS { + __patchable_function_entries : { *(__patchable_function_entries) } + + .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_]*) } +} +#endif + /* bring in arch-specific sections */ #include <asm/module.lds.h> -- 2.28.0.681.g6f77f65b4e-goog
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