On Mon, Oct 12, 2020 at 05:31:51PM -0700, Sami Tolvanen wrote: > 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@xxxxxxxxxx> > Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> > Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> > --- > 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 In looking at this again -- is this ifdef needed? Couldn't this be done unconditionally? (Which would make it an independent change...) -Kees > +/* > + * 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> > -- > 2.28.0.1011.ga647a8990f-goog > -- Kees Cook