From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f193.google.com ([209.85.192.193]:43817 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753922AbeDTHeq (ORCPT ); Fri, 20 Apr 2018 03:34:46 -0400 From: Nicholas Piggin Subject: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected Date: Fri, 20 Apr 2018 17:34:14 +1000 Message-Id: <20180420073414.23169-5-npiggin@gmail.com> In-Reply-To: <20180420073414.23169-1-npiggin@gmail.com> References: <20180420073414.23169-1-npiggin@gmail.com> Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: linuxppc-dev@lists.ozlabs.org Cc: Nicholas Piggin , linux-arch@vger.kernel.org, linux-kbuild@vger.kernel.org, Christophe Leroy , Nicolas Pitre 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 --- 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