kbuild: lto: merge module sections

commit dd2776222abb9893e5b5c237a2c8c880d8854cee upstream.

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>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-6-samitolvanen@google.com
Cc: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sami Tolvanen 2020-12-11 10:46:22 -08:00 committed by Greg Kroah-Hartman
parent 45102b538a
commit 8b53e5f737

View File

@ -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 */