This requires further changes to linker script to KEEP some tables
and wildcard compiler generated sections into the right place. This
includes pp32 modifications from Christophe Leroy.
When compiling powernv_defconfig with this option:
text data bss dec filename
11827621 4810490 1341080 17979191 vmlinux
11752437 4598858 1338776 17690071 vmlinux.dcde
Resulting kernel is almost 400kB smaller (and still boots).
[ppc32 numbers here]
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/kernel/vmlinux.lds.S | 22 +++++++++++-----------
2 files changed, 12 insertions(+), 11 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c32a181a7cbb..ee6dbe2efc8b 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -205,6 +205,7 @@ config PPC
select HAVE_KPROBES
select HAVE_KPROBES_ON_FTRACE
select HAVE_KRETPROBES
+ select HAVE_LD_DEAD_CODE_DATA_ELIMINATION
select HAVE_LIVEPATCH if HAVE_DYNAMIC_FTRACE_WITH_REGS
select HAVE_MEMBLOCK
select HAVE_MEMBLOCK_NODE_MAP
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index c8af90ff49f0..89381dc959ce 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -89,7 +89,7 @@ SECTIONS
*/
.text BLOCK(0) : AT(ADDR(.text) - LOAD_OFFSET) {
#ifdef CONFIG_LD_HEAD_STUB_CATCH
- *(.linker_stub_catch);
+ KEEP(*(.linker_stub_catch));
. = . ;
#endif
@@ -98,7 +98,7 @@ SECTIONS
ALIGN_FUNCTION();
#endif
/* careful! __ftr_alt_* sections need to be close to .text */
- *(.text.hot .text .text.fixup .text.unlikely .fixup __ftr_alt_* .ref.text);
+ *(.text.hot .text .text.[0-9a-zA-Z_]* .text.fixup .text.unlikely .fixup __ftr_alt_* .ref.text);
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
@@ -170,10 +170,10 @@ SECTIONS
.init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
INIT_DATA
__vtop_table_begin = .;
- *(.vtop_fixup);
+ KEEP(*(.vtop_fixup));
__vtop_table_end = .;
__ptov_table_begin = .;
- *(.ptov_fixup);
+ KEEP(*(.ptov_fixup));
__ptov_table_end = .;
}
@@ -194,26 +194,26 @@ SECTIONS
. = ALIGN(8);
__ftr_fixup : AT(ADDR(__ftr_fixup) - LOAD_OFFSET) {
__start___ftr_fixup = .;
- *(__ftr_fixup)
+ KEEP(*(__ftr_fixup))
__stop___ftr_fixup = .;
}
. = ALIGN(8);
__mmu_ftr_fixup : AT(ADDR(__mmu_ftr_fixup) - LOAD_OFFSET) {
__start___mmu_ftr_fixup = .;
- *(__mmu_ftr_fixup)
+ KEEP(*(__mmu_ftr_fixup))
__stop___mmu_ftr_fixup = .;
}
. = ALIGN(8);
__lwsync_fixup : AT(ADDR(__lwsync_fixup) - LOAD_OFFSET) {
__start___lwsync_fixup = .;
- *(__lwsync_fixup)
+ KEEP(*(__lwsync_fixup))
__stop___lwsync_fixup = .;
}
#ifdef CONFIG_PPC64
. = ALIGN(8);
__fw_ftr_fixup : AT(ADDR(__fw_ftr_fixup) - LOAD_OFFSET) {
__start___fw_ftr_fixup = .;
- *(__fw_ftr_fixup)
+ KEEP(*(__fw_ftr_fixup))
__stop___fw_ftr_fixup = .;
}
#endif
@@ -226,7 +226,7 @@ SECTIONS
. = ALIGN(8);
.machine.desc : AT(ADDR(.machine.desc) - LOAD_OFFSET) {
__machine_desc_start = . ;
- *(.machine.desc)
+ KEEP(*(.machine.desc))
__machine_desc_end = . ;
}
#ifdef CONFIG_RELOCATABLE
@@ -274,7 +274,7 @@ SECTIONS
.data : AT(ADDR(.data) - LOAD_OFFSET) {
DATA_DATA
*(.data.rel*)
- *(.sdata)
+ *(SDATA_MAIN)
*(.sdata2)
*(.got.plt) *(.got)
*(.plt)
@@ -289,7 +289,7 @@ SECTIONS
.opd : AT(ADDR(.opd) - LOAD_OFFSET) {
__start_opd = .;
- *(.opd)
+ KEEP(*(.opd))
__end_opd = .;
}
--
2.17.0
