From 4c1d9bb0b5d3c0b3468ac8e68a05972eb957630f Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Wed, 9 May 2018 23:00:01 +1000 Subject: powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected 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, the resulting kernel is almost 400kB smaller (and still boots): text data bss dec filename 11827621 4810490 1341080 17979191 vmlinux 11752437 4598858 1338776 17690071 vmlinux.dcde Mathieu's numbers for custom Mac Mini G4 config has almost 200kB saving. It also had some increase in vmlinux size for as-yet unknown reasons. text data bss dec filename 7461457 2475122 1428064 11364643 vmlinux 7386425 2364370 1425432 11176227 vmlinux.dcde Tested-by: Christophe Leroy [8xx] Tested-by: Mathieu Malaterre [32-bit powermac] Signed-off-by: Nicholas Piggin Signed-off-by: Masahiro Yamada --- 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..52a93cdd04bc 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_MAIN .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 = .; } -- cgit v1.2.3-59-g8ed1b