From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f68.google.com ([209.85.218.68]:36221 "EHLO mail-oi0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754273AbeDTKBM (ORCPT ); Fri, 20 Apr 2018 06:01:12 -0400 MIME-Version: 1.0 In-Reply-To: <20180420073414.23169-5-npiggin@gmail.com> References: <20180420073414.23169-1-npiggin@gmail.com> <20180420073414.23169-5-npiggin@gmail.com> From: Mathieu Malaterre Date: Fri, 20 Apr 2018 12:00:49 +0200 Message-ID: Subject: Re: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected Content-Type: text/plain; charset="UTF-8" Sender: linux-arch-owner@vger.kernel.org List-ID: To: Nicholas Piggin Cc: linuxppc-dev , linux-arch@vger.kernel.org, Nicolas Pitre , linux-kbuild@vger.kernel.org Message-ID: <20180420100049.ipvDP0jUHfD54EJKYCXJVNBUGmtxLTTj1JFdatil2jA@z> On Fri, Apr 20, 2018 at 9:34 AM, Nicholas Piggin wrote: > 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] ^^^ Do you want somebody else to provide those numbers ? > 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 >