Select CONFIG_HAVE_LD_DEAD_CODE_DATA_ELIMINATION for MIPS, allowing the
user to enable dead code elimination. In order for this to work, ensure
that we keep the data bus exception table & the machine list by
annotating them with KEEP.
This shrinks both 32r2el_defconfig & 64r6el_defconfig builds by ~6%, as
shown by numbers from scripts/bloat-o-meter:
| 32r2el_defconfig | 64r6el_defconfig
--------|------------------|------------------
No DCE | 8919864 | 8286307
DCE | 8338988 (-6.51%) | 7741808 (-6.57%)
Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
---
v1: https://patchwork.linux-mips.org/patch/14441/
Changes in v2:
- Drop CONFIG_THIN_ARCHIVES, which is no longer configurable.
- Keep Kconfig alphabetically sorted.
arch/mips/Kconfig | 1 +
arch/mips/kernel/vmlinux.lds.S | 4 ++--
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index e83a8cce41e9..e49b5a0c8585 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -63,6 +63,7 @@ config MIPS
select HAVE_IRQ_TIME_ACCOUNTING
select HAVE_KPROBES
select HAVE_KRETPROBES
+ select HAVE_LD_DEAD_CODE_DATA_ELIMINATION
select HAVE_MEMBLOCK_NODE_MAP
select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NMI
diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S
index 971a504001c2..cb7e9ed7a453 100644
--- a/arch/mips/kernel/vmlinux.lds.S
+++ b/arch/mips/kernel/vmlinux.lds.S
@@ -72,7 +72,7 @@ SECTIONS
/* Exception table for data bus errors */
__dbe_table : {
__start___dbe_table = .;
- *(__dbe_table)
+ KEEP(*(__dbe_table))
__stop___dbe_table = .;
}
@@ -123,7 +123,7 @@ SECTIONS
. = ALIGN(4);
.mips.machines.init : AT(ADDR(.mips.machines.init) - LOAD_OFFSET) {
__mips_machines_start = .;
- *(.mips.machines.init)
+ KEEP(*(.mips.machines.init))
__mips_machines_end = .;
}
--
2.19.1
