Messages in this thread | | | From | Tim Abbott <> | Subject | [PATCH 0/4] Add support for compiling with -ffunction-sections -fdata-sections | Date | Tue, 24 Mar 2009 01:28:41 -0400 |
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Hi Linus,
I'd like to see this patch series merged for 2.6.30. It applies on top of your current master (aka v2.6.29). Patch 1/4 would benefit from special treatment during the merge window, since it makes many small changes in lots of files, and thus is likely to conflict with other changes; the other patches are fairly small.
The purpose of this patch series is to make it possible to build the kernel with "gcc -ffunction-sections -fdata-sections". There are two major applications for this functionality: decreasing vmlinux image size with --gc-sections, and Ksplice.
The original motivation for this functionality was to allow using the linker's unused section garbage collection support (ld --gc-sections) in order to get a smaller vmlinux image for embedded systems. People have been developing patches for supporting building the kernel with -ffunction-sections -fdata-sections for this purpose for a few years now (e.g. [1]). The most recent previous set of patches for --gc-sections was by Denys Vlasenko, and saved 10% on vmlinux size with CONFIG_MODULES=n and 1% with CONFIG_MODULES=y [2,3,4]. The primary source of complexity in the various patch series for doing section garbage collection has been in the patches adding support for compiling the kernel with -ffunction-sections -fdata-sections, so merging this patch series should be a big step towards those significant savings in kernel image size.
[1] <http://lkml.org/lkml/2006/6/4/169> [2] <http://lkml.org/lkml/2007/9/5/90> [3] <http://lkml.org/lkml/2007/9/7/110> [4] <http://lkml.org/lkml/2008/7/1/499>
Support for building the kernel with -ffunction-sections -fdata-sections is the only significant prerequisite change currently required by Ksplice. Ksplice is a system for updating the Linux kernel without rebooting [5].
[5] <http://lkml.org/lkml/2009/2/24/362> is the latest version of the Ksplice patch series
Patches 1/4, 2/4, and 3/4 are independent of each other, but all three are prerequisites for patch 4/4.
--
Anders Kaseorg (1): modpost: Check the section flags, not name, to catch missing "ax"/"aw"
Denys Vlasenko (1): modpost: support objects with more than 64k sections
Tim Abbott (1): Make section names compatible with -ffunction-sections -fdata-sections
Waseem Daher (1): x86: Add an option to compile with -ffunction-sections -fdata-sections
Documentation/mutex-design.txt | 4 +- Makefile | 4 + arch/alpha/kernel/head.S | 2 +- arch/alpha/kernel/init_task.c | 2 +- arch/alpha/kernel/vmlinux.lds.S | 14 ++-- arch/arm/kernel/head-nommu.S | 2 +- arch/arm/kernel/head.S | 2 +- arch/arm/kernel/init_task.c | 2 +- arch/arm/kernel/vmlinux.lds.S | 14 ++-- arch/arm/mm/proc-v6.S | 2 +- arch/arm/mm/proc-v7.S | 2 +- arch/arm/mm/tlb-v6.S | 2 +- arch/arm/mm/tlb-v7.S | 2 +- arch/avr32/kernel/init_task.c | 2 +- arch/avr32/kernel/vmlinux.lds.S | 6 +- arch/avr32/mm/init.c | 2 +- arch/blackfin/kernel/vmlinux.lds.S | 2 +- arch/cris/kernel/process.c | 2 +- arch/cris/kernel/vmlinux.lds.S | 2 +- arch/frv/kernel/break.S | 4 +- arch/frv/kernel/entry.S | 2 +- arch/frv/kernel/head-mmu-fr451.S | 2 +- arch/frv/kernel/head-uc-fr401.S | 2 +- arch/frv/kernel/head-uc-fr451.S | 2 +- arch/frv/kernel/head-uc-fr555.S | 2 +- arch/frv/kernel/head.S | 4 +- arch/frv/kernel/init_task.c | 2 +- arch/frv/kernel/vmlinux.lds.S | 18 ++-- arch/frv/mm/tlb-miss.S | 2 +- arch/h8300/boot/compressed/head.S | 2 +- arch/h8300/boot/compressed/vmlinux.lds | 2 +- arch/h8300/kernel/init_task.c | 2 +- arch/h8300/kernel/vmlinux.lds.S | 2 +- arch/ia64/include/asm/asmmacro.h | 12 +- arch/ia64/include/asm/cache.h | 2 +- arch/ia64/include/asm/percpu.h | 2 +- arch/ia64/kernel/Makefile | 2 +- arch/ia64/kernel/gate-data.S | 2 +- arch/ia64/kernel/gate.S | 8 +- arch/ia64/kernel/gate.lds.S | 10 +- arch/ia64/kernel/head.S | 2 +- arch/ia64/kernel/init_task.c | 4 +- arch/ia64/kernel/ivt.S | 2 +- arch/ia64/kernel/minstate.h | 4 +- arch/ia64/kernel/paravirtentry.S | 2 +- arch/ia64/kernel/vmlinux.lds.S | 48 ++++---- arch/ia64/kvm/vmm_ivt.S | 2 +- arch/ia64/xen/xensetup.S | 2 +- arch/m32r/kernel/head.S | 2 +- arch/m32r/kernel/init_task.c | 2 +- arch/m32r/kernel/vmlinux.lds.S | 8 +- arch/m68k/kernel/head.S | 2 +- arch/m68k/kernel/process.c | 2 +- arch/m68k/kernel/sun3-head.S | 2 +- arch/m68k/kernel/vmlinux-std.lds | 6 +- arch/m68k/kernel/vmlinux-sun3.lds | 4 +- arch/m68knommu/kernel/init_task.c | 2 +- arch/m68knommu/kernel/vmlinux.lds.S | 6 +- arch/m68knommu/platform/68360/head-ram.S | 2 +- arch/m68knommu/platform/68360/head-rom.S | 2 +- arch/mips/kernel/init_task.c | 2 +- arch/mips/kernel/vmlinux.lds.S | 8 +- arch/mips/lasat/image/head.S | 2 +- arch/mips/lasat/image/romscript.normal | 2 +- arch/mn10300/kernel/head.S | 2 +- arch/mn10300/kernel/init_task.c | 2 +- arch/mn10300/kernel/vmlinux.lds.S | 16 ++-- arch/parisc/include/asm/cache.h | 2 +- arch/parisc/include/asm/system.h | 2 +- arch/parisc/kernel/head.S | 2 +- arch/parisc/kernel/init_task.c | 8 +- arch/parisc/kernel/vmlinux.lds.S | 26 +++--- arch/powerpc/include/asm/cache.h | 2 +- arch/powerpc/include/asm/page_64.h | 2 +- arch/powerpc/include/asm/ppc_asm.h | 4 +- arch/powerpc/kernel/head_32.S | 2 +- arch/powerpc/kernel/head_40x.S | 2 +- arch/powerpc/kernel/head_44x.S | 2 +- arch/powerpc/kernel/head_8xx.S | 2 +- arch/powerpc/kernel/head_fsl_booke.S | 2 +- arch/powerpc/kernel/init_task.c | 2 +- arch/powerpc/kernel/machine_kexec_64.c | 2 +- arch/powerpc/kernel/vdso.c | 2 +- arch/powerpc/kernel/vdso32/vdso32_wrapper.S | 2 +- arch/powerpc/kernel/vdso64/vdso64_wrapper.S | 2 +- arch/powerpc/kernel/vmlinux.lds.S | 28 +++--- arch/s390/include/asm/cache.h | 2 +- arch/s390/kernel/head.S | 2 +- arch/s390/kernel/init_task.c | 2 +- arch/s390/kernel/vdso.c | 2 +- arch/s390/kernel/vdso32/vdso32_wrapper.S | 2 +- arch/s390/kernel/vdso64/vdso64_wrapper.S | 2 +- arch/s390/kernel/vmlinux.lds.S | 20 ++-- arch/sh/include/asm/cache.h | 2 +- arch/sh/kernel/cpu/sh5/entry.S | 4 +- arch/sh/kernel/head_32.S | 2 +- arch/sh/kernel/head_64.S | 2 +- arch/sh/kernel/init_task.c | 2 +- arch/sh/kernel/irq.c | 4 +- arch/sh/kernel/vmlinux_32.lds.S | 14 ++-- arch/sh/kernel/vmlinux_64.lds.S | 14 ++-- arch/sparc/boot/btfixupprep.c | 4 +- arch/sparc/include/asm/cache.h | 2 +- arch/sparc/kernel/head_32.S | 4 +- arch/sparc/kernel/head_64.S | 2 +- arch/sparc/kernel/init_task.c | 2 +- arch/sparc/kernel/vmlinux.lds.S | 14 ++-- arch/um/include/asm/common.lds.S | 4 +- arch/um/kernel/dyn.lds.S | 4 +- arch/um/kernel/init_task.c | 4 +- arch/um/kernel/uml.lds.S | 4 +- arch/x86/Kconfig | 1 + arch/x86/boot/compressed/head_32.S | 2 +- arch/x86/boot/compressed/head_64.S | 2 +- arch/x86/boot/compressed/relocs.c | 2 +- arch/x86/boot/compressed/vmlinux.scr | 2 +- arch/x86/boot/compressed/vmlinux_32.lds | 14 ++- arch/x86/boot/compressed/vmlinux_64.lds | 10 +- arch/x86/include/asm/cache.h | 4 +- arch/x86/kernel/acpi/wakeup_32.S | 2 +- arch/x86/kernel/head_32.S | 6 +- arch/x86/kernel/head_64.S | 4 +- arch/x86/kernel/init_task.c | 4 +- arch/x86/kernel/traps.c | 2 +- arch/x86/kernel/vmlinux_32.lds.S | 37 ++++--- arch/x86/kernel/vmlinux_64.lds.S | 27 +++--- arch/xtensa/kernel/head.S | 2 +- arch/xtensa/kernel/init_task.c | 2 +- arch/xtensa/kernel/vmlinux.lds.S | 6 +- include/asm-frv/init.h | 8 +- include/asm-generic/vmlinux.lds.h | 19 ++-- include/linux/cache.h | 2 +- include/linux/init.h | 8 +- include/linux/linkage.h | 4 +- include/linux/percpu.h | 10 +- include/linux/spinlock.h | 2 +- kernel/module.c | 2 +- lib/Kconfig.debug | 18 +++ scripts/mod/file2alias.c | 6 +- scripts/mod/modpost.c | 155 ++++++++++++++++----------- scripts/mod/modpost.h | 43 ++++++++ scripts/recordmcount.pl | 6 +- 142 files changed, 515 insertions(+), 409 deletions(-)
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