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 <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Cc: Stephen Boyd <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
diff --git a/scripts/module.lds.S b/scripts/module.lds.S
index 69b9b71..18d5b84 100644
--- a/scripts/module.lds.S
+++ b/scripts/module.lds.S
@@ -23,6 +23,30 @@
.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 */
