Section ranges are on one of the types of custom sections types used in Linux. This provides a series of helpers for defining them and using them. Most importantly this also enables us to avoid modifying the linker script when we add a new section range. It turns out a lot of custom sections are actually section ranges, and these are typically spelled out in their architecture specific asm/sections.h file -- we enable architectures to override what asm is used for section ranges but start by default trusting the asm-generic version all around. Although typically you will not want to have section ranges ordered we must use SORT() on vmlinux.lds.S for section ranges to enable us to extend a section range without modifying the linker script. To accomplish this we use a special order string for the first element of a section range -- the empty string "" (refer to __SECTION_RANGE_BEGIN()), then "~" for the last element (refer to __SECTION_RANGE_BEGIN()). If you use the "any" order for elements in between and use SORT() you end up keeping any added element in betweeen and a reference to the beginning and end of the section range without requiring custom linker script modifications. Specific order annotations are also supported to help construct synthetic functions, a demo for which will be provided later. v5: o Use ..rng.* instead of .rng.* as suggested by Nicholas Piggin. This is the typical way to avoid clash with compiler generated section. o Replace section macros with section names o Extend commit log to justify SORT() and explain why and how we use specific special strings for the beginning, end elements of a section range and the "any" order for elements in between. o Drop SECTION_RNG_ALL() -- we no longer need this on linker scripts o To make this easier to read, as per Nicholas Piggin, add our own SECTION_RANGE_START(), SECTION_RANGE_END(). After reviewing the changes affected by this it seemed clearer and better then to also use our own specific SECTION_RANGE_SIZE(), and SECTION_RANGE_EMPTY(), and SECTION_RANGE_ALIGNMENT() as well. o We were using LINUX_SECTION_START() and LINUX_SECTION_END() in some places but in some other places VMLINUX_SYMBOL(name), VMLINUX_SYMBOL(name##__end). Since we are adding SECTION_RANGE_START() and SECTION_RANGE_END() just use those consistently. o Move the linker table *(SORT(.data.rng.*)) to be present before the recently added *(.data.[0-9a-zA-Z_]*) to ensure we keep sort order on the section range. o Adds the "Linux section ordering" documentation, as its much more relevant after this patch, in particular when treating the "any" order level. o Fix powerpc .text use: -- it does not use TEXT_TEXT so we must add our *(SORT(.text.rng.*)) to its linker script manually. v4: o tons of documentation love o fix arch/x86/tools/relocs.c typo - which caused compilation issues on old toolchains o port to new shiny sphinx documentation o sprinkle a few more needed VMLINUX_SYMBOL() - fixes compilation on blackfin o name changes as suggested by Boris: - %s/SECTION_TYPE_RANGES/rng/g - %s/SECTION_TYPE/SECTION_CORE/g - %s/section_type_asmtype/section_core_type/g - %s/section_type/section_core/g - %s/section_rng/set_section_rng/g - rebrand DECLARE_SECTION_RNG() as DEFINE_SECTION_RANGE() - this is the asm version of the respective C version, this will have a userspace C demo added later. o move __LINUX_RANGE() and __LINUX_RANGE_ORDER() - fixes builds on sparc o adds section ranges to linker script o rename SECTION_RANGE_ALL() o use default alignment, fixes builds on powerpc and arm for both __LINUX_RANGE() and __LINUX_RANGE_ORDER() o expand documentation to document modules support o add maintainers o use generic-y v3: new in this series, uses copyleft-next Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxxxx> --- Documentation/sections/index.rst | 1 + Documentation/sections/ranges.rst | 74 +++++++++++++ Documentation/sections/section-core.rst | 5 + MAINTAINERS | 10 ++ arch/alpha/include/asm/Kbuild | 1 + arch/arc/include/asm/Kbuild | 1 + arch/arm/include/asm/Kbuild | 1 + arch/arm64/include/asm/Kbuild | 1 + arch/avr32/include/asm/Kbuild | 1 + arch/blackfin/include/asm/Kbuild | 1 + arch/c6x/include/asm/Kbuild | 1 + arch/cris/include/asm/Kbuild | 1 + arch/frv/include/asm/Kbuild | 1 + arch/h8300/include/asm/Kbuild | 1 + arch/hexagon/include/asm/Kbuild | 1 + arch/ia64/include/asm/Kbuild | 1 + arch/m32r/include/asm/Kbuild | 1 + arch/m68k/include/asm/Kbuild | 1 + arch/metag/include/asm/Kbuild | 1 + arch/microblaze/include/asm/Kbuild | 1 + arch/mips/include/asm/Kbuild | 1 + arch/mn10300/include/asm/Kbuild | 1 + arch/nios2/include/asm/Kbuild | 1 + arch/openrisc/include/asm/Kbuild | 1 + arch/parisc/include/asm/Kbuild | 1 + arch/powerpc/include/asm/Kbuild | 1 + arch/powerpc/kernel/vmlinux.lds.S | 1 + arch/s390/include/asm/Kbuild | 1 + arch/score/include/asm/Kbuild | 1 + arch/sh/include/asm/Kbuild | 1 + arch/sparc/include/asm/Kbuild | 1 + arch/tile/include/asm/Kbuild | 1 + arch/um/include/asm/Kbuild | 1 + arch/unicore32/include/asm/Kbuild | 1 + arch/x86/include/asm/Kbuild | 1 + arch/x86/tools/relocs.c | 2 + arch/xtensa/include/asm/Kbuild | 1 + include/asm-generic/ranges.h | 93 ++++++++++++++++ include/asm-generic/section-core.h | 41 +++++++ include/asm-generic/vmlinux.lds.h | 12 ++- include/linux/ranges.h | 183 ++++++++++++++++++++++++++++++++ 41 files changed, 451 insertions(+), 2 deletions(-) create mode 100644 Documentation/sections/ranges.rst create mode 100644 include/asm-generic/ranges.h create mode 100644 include/linux/ranges.h diff --git a/Documentation/sections/index.rst b/Documentation/sections/index.rst index f37511ef05e7..4a1df389fa91 100644 --- a/Documentation/sections/index.rst +++ b/Documentation/sections/index.rst @@ -15,3 +15,4 @@ common a set of Linux helpers for ELF sections are also documented. background section-core + ranges diff --git a/Documentation/sections/ranges.rst b/Documentation/sections/ranges.rst new file mode 100644 index 000000000000..d9d3af4e52cb --- /dev/null +++ b/Documentation/sections/ranges.rst @@ -0,0 +1,74 @@ +==================== +Linux section ranges +==================== + +This documents Linux' use of section ranges, how you can use +them and how they work. + +About section ranges +==================== + +Introduction +------------ +.. kernel-doc:: include/linux/ranges.h + :doc: Introduction + +Section range module support +---------------------------- +.. kernel-doc:: include/linux/ranges.h + :doc: Section range module support + +Section range helpers +===================== +.. kernel-doc:: include/linux/ranges.h + :doc: Section range helpers + +SECTION_RANGE_START +------------------- +.. kernel-doc:: include/linux/ranges.h + :functions: SECTION_RANGE_START + +SECTION_RANGE_END +----------------- +.. kernel-doc:: include/linux/ranges.h + :functions: SECTION_RANGE_END + +SECTION_RANGE_SIZE +------------------ +.. kernel-doc:: include/linux/ranges.h + :functions: SECTION_RANGE_SIZE + +SECTION_RANGE_EMPTY +------------------- +.. kernel-doc:: include/linux/ranges.h + :functions: SECTION_RANGE_EMPTY + +SECTION_RANGE_ADDR_WITHIN +------------------------- +.. kernel-doc:: include/linux/ranges.h + :functions: SECTION_RANGE_ADDR_WITHIN + +SECTION_RANGE_ALIGNMENT +------------------------- +.. kernel-doc:: include/linux/ranges.h + :functions: SECTION_RANGE_ALIGNMENT + +DECLARE_SECTION_RANGE +--------------------- +.. kernel-doc:: include/linux/ranges.h + :functions: DECLARE_SECTION_RANGE + +DEFINE_SECTION_RANGE +-------------------- +.. kernel-doc:: include/linux/ranges.h + :functions: DEFINE_SECTION_RANGE + +__LINUX_RANGE +------------- +.. kernel-doc:: include/asm-generic/ranges.h + :functions: __LINUX_RANGE + +__LINUX_RANGE_ORDER +------------------- +.. kernel-doc:: include/asm-generic/ranges.h + :functions: __LINUX_RANGE_ORDER diff --git a/Documentation/sections/section-core.rst b/Documentation/sections/section-core.rst index ac5815a0d9b3..1f613a6c7b78 100644 --- a/Documentation/sections/section-core.rst +++ b/Documentation/sections/section-core.rst @@ -114,6 +114,11 @@ Linux .ref\* sections .. kernel-doc:: include/asm-generic/section-core.h :doc: .ref.rodata +Linux section ordering +====================== +.. kernel-doc:: include/asm-generic/section-core.h + :doc: Linux section ordering + Generic Linux kernel section helpers ==================================== diff --git a/MAINTAINERS b/MAINTAINERS index 308826f5094b..93bebccad674 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5422,6 +5422,16 @@ S: Supported F: drivers/base/power/domain*.c F: include/linux/pm_domain.h +GENERIC SECTION RANGES +M: "Luis R. Rodriguez" <mcgrof@xxxxxxxxxx> +M: "H. Peter Anvin" <hpa@xxxxxxxxx> +L: linux-arch@xxxxxxxxxxxxxxx +L: linux-kernel@xxxxxxxxxxxxxxx +S: Supported +F: include/asm-generic/ranges.h +F: include/linux/ranges.h +F: Documentation/sections/ranges.rst + GENERIC SECTIONS M: "Luis R. Rodriguez" <mcgrof@xxxxxxxxxx> M: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> diff --git a/arch/alpha/include/asm/Kbuild b/arch/alpha/include/asm/Kbuild index 5422827f1585..e44c896b91c4 100644 --- a/arch/alpha/include/asm/Kbuild +++ b/arch/alpha/include/asm/Kbuild @@ -11,3 +11,4 @@ generic-y += preempt.h generic-y += sections.h generic-y += trace_clock.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild index 7b2cb3dea5fc..a374b7f83888 100644 --- a/arch/arc/include/asm/Kbuild +++ b/arch/arc/include/asm/Kbuild @@ -52,3 +52,4 @@ generic-y += vga.h generic-y += word-at-a-time.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild index 9b69a22a9ae1..0d47f98ccbc0 100644 --- a/arch/arm/include/asm/Kbuild +++ b/arch/arm/include/asm/Kbuild @@ -42,3 +42,4 @@ generic-y += unaligned.h generated-y += mach-types.h generated-y += unistd-nr.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/arm64/include/asm/Kbuild b/arch/arm64/include/asm/Kbuild index 00ace5e826f1..e9939cbd9067 100644 --- a/arch/arm64/include/asm/Kbuild +++ b/arch/arm64/include/asm/Kbuild @@ -46,3 +46,4 @@ generic-y += user.h generic-y += vga.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/avr32/include/asm/Kbuild b/arch/avr32/include/asm/Kbuild index f2c3b656a0e7..edc176348d7c 100644 --- a/arch/avr32/include/asm/Kbuild +++ b/arch/avr32/include/asm/Kbuild @@ -23,3 +23,4 @@ generic-y += vga.h generic-y += word-at-a-time.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/blackfin/include/asm/Kbuild b/arch/blackfin/include/asm/Kbuild index bf20541bcf21..3428415b1996 100644 --- a/arch/blackfin/include/asm/Kbuild +++ b/arch/blackfin/include/asm/Kbuild @@ -48,3 +48,4 @@ generic-y += user.h generic-y += word-at-a-time.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/c6x/include/asm/Kbuild b/arch/c6x/include/asm/Kbuild index 38127ce747be..cede2a950fbf 100644 --- a/arch/c6x/include/asm/Kbuild +++ b/arch/c6x/include/asm/Kbuild @@ -63,3 +63,4 @@ generic-y += vga.h generic-y += word-at-a-time.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/cris/include/asm/Kbuild b/arch/cris/include/asm/Kbuild index 385cd88a9d9e..fb8bb4112773 100644 --- a/arch/cris/include/asm/Kbuild +++ b/arch/cris/include/asm/Kbuild @@ -46,3 +46,4 @@ generic-y += vga.h generic-y += word-at-a-time.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/frv/include/asm/Kbuild b/arch/frv/include/asm/Kbuild index 46d7c599d9b8..5191fec655d7 100644 --- a/arch/frv/include/asm/Kbuild +++ b/arch/frv/include/asm/Kbuild @@ -9,3 +9,4 @@ generic-y += preempt.h generic-y += trace_clock.h generic-y += word-at-a-time.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/h8300/include/asm/Kbuild b/arch/h8300/include/asm/Kbuild index 1ec04ec1c82b..7929a992566c 100644 --- a/arch/h8300/include/asm/Kbuild +++ b/arch/h8300/include/asm/Kbuild @@ -76,3 +76,4 @@ generic-y += vga.h generic-y += word-at-a-time.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/hexagon/include/asm/Kbuild b/arch/hexagon/include/asm/Kbuild index 37d7bfae7619..af17ee334788 100644 --- a/arch/hexagon/include/asm/Kbuild +++ b/arch/hexagon/include/asm/Kbuild @@ -61,3 +61,4 @@ generic-y += vga.h generic-y += word-at-a-time.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/ia64/include/asm/Kbuild b/arch/ia64/include/asm/Kbuild index 672c6d5da18c..d8f226b35a0a 100644 --- a/arch/ia64/include/asm/Kbuild +++ b/arch/ia64/include/asm/Kbuild @@ -10,3 +10,4 @@ generic-y += trace_clock.h generic-y += vtime.h generic-y += word-at-a-time.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/m32r/include/asm/Kbuild b/arch/m32r/include/asm/Kbuild index 6111e1523750..1c6504d29312 100644 --- a/arch/m32r/include/asm/Kbuild +++ b/arch/m32r/include/asm/Kbuild @@ -12,3 +12,4 @@ generic-y += sections.h generic-y += trace_clock.h generic-y += word-at-a-time.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/m68k/include/asm/Kbuild b/arch/m68k/include/asm/Kbuild index 1277b45bf4f9..006e2863ad37 100644 --- a/arch/m68k/include/asm/Kbuild +++ b/arch/m68k/include/asm/Kbuild @@ -35,3 +35,4 @@ generic-y += types.h generic-y += word-at-a-time.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/metag/include/asm/Kbuild b/arch/metag/include/asm/Kbuild index b1011375cd7a..4a8471434a3e 100644 --- a/arch/metag/include/asm/Kbuild +++ b/arch/metag/include/asm/Kbuild @@ -56,3 +56,4 @@ generic-y += vga.h generic-y += word-at-a-time.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/microblaze/include/asm/Kbuild b/arch/microblaze/include/asm/Kbuild index c6c2cf6edc98..63c083a1f8da 100644 --- a/arch/microblaze/include/asm/Kbuild +++ b/arch/microblaze/include/asm/Kbuild @@ -12,3 +12,4 @@ generic-y += syscalls.h generic-y += trace_clock.h generic-y += word-at-a-time.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/mips/include/asm/Kbuild b/arch/mips/include/asm/Kbuild index a67d3177f3ca..288e21b64170 100644 --- a/arch/mips/include/asm/Kbuild +++ b/arch/mips/include/asm/Kbuild @@ -21,3 +21,4 @@ generic-y += user.h generic-y += word-at-a-time.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/mn10300/include/asm/Kbuild b/arch/mn10300/include/asm/Kbuild index f8145bc85835..656af7b69940 100644 --- a/arch/mn10300/include/asm/Kbuild +++ b/arch/mn10300/include/asm/Kbuild @@ -11,3 +11,4 @@ generic-y += sections.h generic-y += trace_clock.h generic-y += word-at-a-time.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/nios2/include/asm/Kbuild b/arch/nios2/include/asm/Kbuild index c9c7cb82b00f..c55880659d67 100644 --- a/arch/nios2/include/asm/Kbuild +++ b/arch/nios2/include/asm/Kbuild @@ -64,3 +64,4 @@ generic-y += vga.h generic-y += word-at-a-time.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/openrisc/include/asm/Kbuild b/arch/openrisc/include/asm/Kbuild index 86175e701869..7d6a704b808c 100644 --- a/arch/openrisc/include/asm/Kbuild +++ b/arch/openrisc/include/asm/Kbuild @@ -72,3 +72,4 @@ generic-y += vga.h generic-y += word-at-a-time.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/parisc/include/asm/Kbuild b/arch/parisc/include/asm/Kbuild index 18a9d4c5ead7..f11d1249738f 100644 --- a/arch/parisc/include/asm/Kbuild +++ b/arch/parisc/include/asm/Kbuild @@ -29,3 +29,4 @@ generic-y += vga.h generic-y += word-at-a-time.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/powerpc/include/asm/Kbuild b/arch/powerpc/include/asm/Kbuild index 4322d9746cdb..60d8349241a7 100644 --- a/arch/powerpc/include/asm/Kbuild +++ b/arch/powerpc/include/asm/Kbuild @@ -9,3 +9,4 @@ generic-y += preempt.h generic-y += rwsem.h generic-y += vtime.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index 7394b770ae1f..fcfc9d102348 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -107,6 +107,7 @@ SECTIONS #endif /* careful! __ftr_alt_* sections need to be close to .text */ *(.text .fixup __ftr_alt_* .ref.text) + *(SORT(.text.rng.*)) SCHED_TEXT CPUIDLE_TEXT LOCK_TEXT diff --git a/arch/s390/include/asm/Kbuild b/arch/s390/include/asm/Kbuild index 63a1c2924b91..c1b85a361e5d 100644 --- a/arch/s390/include/asm/Kbuild +++ b/arch/s390/include/asm/Kbuild @@ -9,3 +9,4 @@ generic-y += preempt.h generic-y += trace_clock.h generic-y += word-at-a-time.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/score/include/asm/Kbuild b/arch/score/include/asm/Kbuild index f089a264cd38..f0cdb2cbca4d 100644 --- a/arch/score/include/asm/Kbuild +++ b/arch/score/include/asm/Kbuild @@ -15,3 +15,4 @@ generic-y += xor.h generic-y += serial.h generic-y += word-at-a-time.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/sh/include/asm/Kbuild b/arch/sh/include/asm/Kbuild index 7b0356dca562..c9bb7932a3d1 100644 --- a/arch/sh/include/asm/Kbuild +++ b/arch/sh/include/asm/Kbuild @@ -40,3 +40,4 @@ generic-y += trace_clock.h generic-y += ucontext.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/sparc/include/asm/Kbuild b/arch/sparc/include/asm/Kbuild index 438f86573dc5..28280887ac79 100644 --- a/arch/sparc/include/asm/Kbuild +++ b/arch/sparc/include/asm/Kbuild @@ -22,3 +22,4 @@ generic-y += trace_clock.h generic-y += types.h generic-y += word-at-a-time.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/tile/include/asm/Kbuild b/arch/tile/include/asm/Kbuild index fb6b831c1fba..33f7069763ae 100644 --- a/arch/tile/include/asm/Kbuild +++ b/arch/tile/include/asm/Kbuild @@ -41,3 +41,4 @@ generic-y += trace_clock.h generic-y += types.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild index 580bd5ff828f..b952dcb3e216 100644 --- a/arch/um/include/asm/Kbuild +++ b/arch/um/include/asm/Kbuild @@ -27,3 +27,4 @@ generic-y += trace_clock.h generic-y += word-at-a-time.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/unicore32/include/asm/Kbuild b/arch/unicore32/include/asm/Kbuild index 8578702d4998..93abbfdab543 100644 --- a/arch/unicore32/include/asm/Kbuild +++ b/arch/unicore32/include/asm/Kbuild @@ -61,3 +61,4 @@ generic-y += user.h generic-y += vga.h generic-y += word-at-a-time.h generic-y += xor.h +generic-y += ranges.h diff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild index af975f21eeee..f672f2fc181d 100644 --- a/arch/x86/include/asm/Kbuild +++ b/arch/x86/include/asm/Kbuild @@ -13,3 +13,4 @@ generic-y += early_ioremap.h generic-y += mcs_spinlock.h generic-y += mm-arch-hooks.h generic-y += section-core.h +generic-y += ranges.h diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c index 73eb7fd4aec4..f96fa2ddf7c9 100644 --- a/arch/x86/tools/relocs.c +++ b/arch/x86/tools/relocs.c @@ -68,6 +68,8 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = { "__end_rodata|" "__initramfs_start|" "(jiffies|jiffies_64)|" + ".rodata..rng.*|" + ".init.text..rng.*|" #if ELF_BITS == 64 "__per_cpu_load|" "init_per_cpu__.*|" diff --git a/arch/xtensa/include/asm/Kbuild b/arch/xtensa/include/asm/Kbuild index 7879c31e66a7..2b7fe48c0225 100644 --- a/arch/xtensa/include/asm/Kbuild +++ b/arch/xtensa/include/asm/Kbuild @@ -33,3 +33,4 @@ generic-y += trace_clock.h generic-y += word-at-a-time.h generic-y += xor.h generic-y += section-core.h +generic-y += ranges.h diff --git a/include/asm-generic/ranges.h b/include/asm-generic/ranges.h new file mode 100644 index 000000000000..75c196864f45 --- /dev/null +++ b/include/asm-generic/ranges.h @@ -0,0 +1,93 @@ +#ifndef _ASM_GENERIC_RANGES_H_ +#define _ASM_GENERIC_RANGES_H_ +/* + * Copyright (C) 2016 Luis R. Rodriguez <mcgrof@xxxxxxxxxx> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of copyleft-next (version 0.3.1 or later) as published + * at http://copyleft-next.org/. + */ +#include <asm/section-core.h> + +#ifndef set_section_rng +# define set_section_rng(section, name, flags) \ + set_section_core(section, rng, name, \ + any, flags) +#endif + +#ifndef set_section_rng_type +# define set_section_rng_type(section, name, flags, type) \ + set_section_core_type(section, rng, name, \ + any, flags, type) +#endif + +#ifndef set_section_rng_level +# define set_section_rng_level(section, name, level, flags) \ + set_section_core(section, rng, name, level, flags) +#endif + +#ifndef push_section_rng +# define push_section_rng(section, name, flags) \ + push_section_core(section, rng, name, \ + any, flags) +#endif + +#ifndef push_section_rng_level +# define push_section_rng_level(section, name, level, flags) \ + push_section_core(section, rng, name, \ + level, flags) +#endif + +#ifndef __ASSEMBLY__ +/** + * __LINUX_RANGE - short hand association into a section range + * + * @section: ELF section name to place section range into + * @name: section range name + * + * This helper can be used by subsystems to define their own subsystem + * specific helpers to easily associate a piece of code being defined to a + * section range. + */ +#define __LINUX_RANGE(section, name) \ + __attribute__((__section__(#section "..rng.name.any"))) + +/** + * __LINUX_RANGE_ORDER - short hand association into a section range of order + * + * @section: ELF section name to place section range into + * @name: section range name + * @level: order level, a number. The order level gets tucked into the + * section as a postfix string. Order levels are sorted using + * binutils SORT(), the number is sorted as a string, as such be + * sure to fill with zeroes any empty digits. For instance if you are + * using 3 levels of digits for order levels, use 001 for the first entry, + * 0002 for the second, 999 for the last entry. You can use however many + * digits you need. + * + * This helper can be used by subsystems to define their own subsystem specific + * helpers to easily associate a piece of code being defined to a section range + * with an associated specific order level. The order level provides the + * ability for explicit user ordering of code. Sorting takes place at link + * time, after compilation. + */ +#define __LINUX_RANGE_ORDER(section, name, level) \ + __attribute__((__section__(#section "..rng.name." #level))) + +#endif /* __ASSEMBLY__ */ + +#ifdef __ASSEMBLER__ + +#ifndef DEFINE_SECTION_RANGE +#define DEFINE_SECTION_RANGE(section, name) \ + push_section_rng_level(section, name,,) ; \ + .globl name ; \ +name: ; \ + .popsection \ + \ + push_section_rng_level(section, name, ~,) ; \ + .popsection +#endif +#endif /* __ASSEMBLER__ */ + +#endif /* _ASM_GENERIC_RANGES_H_ */ diff --git a/include/asm-generic/section-core.h b/include/asm-generic/section-core.h index bb16befc4251..65fb076765f8 100644 --- a/include/asm-generic/section-core.h +++ b/include/asm-generic/section-core.h @@ -183,6 +183,47 @@ * or data structures part of the init sections. */ +/** + * DOC: Linux section ordering + * + * Linux may use binutils linker-script 'SORT()' on sections to sort Linux + * sections alpha numerically. Linux has historically used 'SORT()' in + * ``include/asm-generic/vmlinux.lds.h``, its a well established practice. If + * 'SORT()' is used on a section one can provide ordering using a postfix on + * each section entry added. For instance if a linker script uses:: + * + * SORT(.foo.*) + * + * one can then add entries with explicit ordering using numeric postfixes for + * each entry, we refer to these as 'order levels'. Since 'SORT()' sorts alpha + * numerically a specific series set of digits must be agreed a-priori which + * would give also an idea of the max expected number of entries added to a + * section. For instance, if you expect a maximum of 999 entries you can use + * 3 digits for a section order level. If you wanted an entry to be ordered + * first you could use the postfix '000', if you wanted an entry to follow this + * you could use '001', and so on. We could for instance have:: + * + * .foo.000 + * .foo.001 + * .foo.002 + * + * Often times one may want the option to specify no order is required for + * certain elements added to a section which does use 'SORT()' on the linker + * script. You can use any arbitrary string value to to specify no order is + * used, so long as its used consistantly. For instance, one possibility is to + * use the 'any' postfix. All entries on the section would then have no + * specific ordering:: + * + * .foo.any + * .foo.any + * .foo.any + * + * To help establish a convention we reserve the special name 'any' for this + * purpose. Developers can use and expect the 'any' postfix string on sections + * as a helper to annotate section ordering at link time is not relevant + * for entries on a section. + */ + /* Can be used on foo.S for instance */ #ifndef __set_section_core_type # define __set_section_core_type(___section, ___core, ___name, \ diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 483f60c451f9..71bfd3b3c719 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -56,6 +56,7 @@ #include <linux/export.h> #include <asm/section-core.h> +#include <asm/ranges.h> /* Align . to a 8 byte boundary equals to maximum function alignment. */ #define ALIGN_FUNCTION() . = ALIGN(8) @@ -205,6 +206,7 @@ */ #define DATA_DATA \ *(.data .data.[0-9a-zA-Z_]*) \ + *(SORT(.data..rng.*)) \ *(.ref.data) \ *(.data..shared_aligned) /* percpu related */ \ MEM_KEEP(init.data) \ @@ -273,7 +275,9 @@ . = ALIGN((align)); \ .rodata : AT(ADDR(.rodata) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start_rodata) = .; \ - *(.rodata) *(.rodata.*) \ + *(.rodata) \ + *(SORT(.rodata..rng.*)) \ + *(.rodata.*) \ RO_AFTER_INIT_DATA /* Read only after init */ \ KEEP(*(__vermagic)) /* Kernel version magic */ \ . = ALIGN(8); \ @@ -446,7 +450,9 @@ * conflicting section names, and must pull in .text.[0-9a-zA-Z_]* */ #define TEXT_TEXT \ ALIGN_FUNCTION(); \ - *(.text.hot .text .text.fixup .text.unlikely) \ + *(.text.hot .text) \ + *(SORT(.text..rng.*)) \ + *(.text.fixup .text.unlikely) \ *(.ref.text) \ MEM_KEEP(init.text) \ MEM_KEEP(exit.text) \ @@ -549,6 +555,7 @@ #define INIT_DATA \ KEEP(*(SORT(___kentry+*))) \ *(.init.data) \ + *(SORT(.init.data..rng.*)) \ MEM_DISCARD(init.data) \ KERNEL_CTORS() \ MCOUNT_REC() \ @@ -572,6 +579,7 @@ #define INIT_TEXT \ *(.init.text) \ + *(SORT(.init.text..rng.*)) \ *(.text.startup) \ MEM_DISCARD(init.text) diff --git a/include/linux/ranges.h b/include/linux/ranges.h new file mode 100644 index 000000000000..1e64674f6d7d --- /dev/null +++ b/include/linux/ranges.h @@ -0,0 +1,183 @@ +#ifndef _LINUX_RANGES_H +#define _LINUX_RANGES_H +/* + * Linux section ranges + * + * Copyright (C) 2016 Luis R. Rodriguez <mcgrof@xxxxxxxxxx> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of copyleft-next (version 0.3.1 or later) as published + * at http://copyleft-next.org/. + */ +#include <linux/sections.h> +#include <asm/ranges.h> + +#ifndef __ASSEMBLY__ + +/** + * DOC: Introduction + * + * A section ranges consists of explicitly annotated series executable code + * stitched together for the purpose of selective placement into standard or + * architecture specific ELF sections. What ELF section is used is utility + * specific. Linux has historically implicitly used section ranges, however + * they were all built in an adhoc manner and typically required linker script + * modifications per architecture. The section range API allows adding new + * bundles of stiched executable code into custom ELF sections by only + * modifying C or asm code in an architecture agnostic form. + * + * This documents the set of helpers available to declare, and define section + * ranges and associate each section range to a specific Linux ELF section. + */ + +/** + * DOC: Section range module support + * + * Modules can use section ranges, however the section range definition must be + * built-in to the kernel. That is, the code that implements + * DEFINE_SECTION_RANGE() must be built-in, and modular code cannot add more + * items in to the section range (with __LINUX_RANGE() or + * __LINUX_RANGE_ORDER()), unless kernel/module.c find_module_sections() and + * module-common.lds.S are updated accordingly with a respective module + * notifier to account for updates. This restriction may be enhanced in the + * future. + */ + +/** + * DOC: Section range helpers + * + * These are helpers for section ranges. + */ + +/** + * SECTION_RANGE_START - get address of start of section range + * + * @name: name of the section range + * + * This gives you the start address of the section range. + * This should give you the address of the first entry. + * + */ +#define SECTION_RANGE_START(name) LINUX_SECTION_START(name) + +/** + * SECTION_RANGE_END - get address of end of the section range + * + * @name: name of the section range + * + * This gives you the end address of the linker table. + * This will match the start address if the linker table + * is empty. + */ +#define SECTION_RANGE_END(name) LINUX_SECTION_END(name) + +/** + * SECTION_RANGE_SIZE - get number of entries in the section range + * + * @name: name of the section range + * + * This gives you the number of entries in the section range. + * Example usage: + * + * unsigned int num_ents = LINKTABLE_SIZE(some_fns); + */ +#define SECTION_RANGE_SIZE(name) \ + ((SECTION_RANGE_END(name)) - (SECTION_RANGE_START(name))) + +/** + * SECTION_RANGE_EMPTY - check if section range has no entries + * + * @name: name of the section range + * + * Returns true if the section range is emtpy. + * + * bool is_empty = LINKTABLE_EMPTY(some_fns); + */ +#define SECTION_RANGE_EMPTY(name) (SECTION_RANGE_SIZE(name) == 0) + +/** + * SECTION_RANGE_ADDR_WITHIN - returns true if address is in the section range + * + * @name: name of the section range + * @addr: address to query for + * + * Returns true if the address is in the section range. + */ +#define SECTION_RANGE_ADDR_WITHIN(name, addr) \ + (addr >= (unsigned long) SECTION_RANGE_START(name) && \ + addr < (unsigned long) SECTION_RANGE_END(name)) + +/** + * SECTION_RANGE_ALIGNMENT - get the alignment of the section range + * + * @name: name of linker table + * + * Gives you the alignment for the section range. + */ +#define SECTION_RANGE_ALIGNMENT(name) LINUX_SECTION_ALIGNMENT(name) + +/** + * DECLARE_SECTION_RANGE - Declares a section range + * + * @name: section range name + * + * Declares a section range to help code access the range. Typically if + * a subsystems needs code to have direct access to the section range the + * subsystem's header file would declare the section range. Care should be + * taken to only declare the section range in a header file if access to it + * is truly needed outside of the code defining it. You typically would + * rather instead provide helpers which access the section range with special + * code on behalf of the caller. + */ +#define DECLARE_SECTION_RANGE(name) \ + DECLARE_LINUX_SECTION_RO(char, name) + +/** + * __SECTION_RANGE_BEGIN - Constructs the beginning of a section range + * + * @name: section range name + * @__section: ELF section to place section range into + * + * Constructs the beginning of a section range. You will typically not need + * to use this directly. + */ +#define __SECTION_RANGE_BEGIN(name, __section) \ + const __typeof__(SECTION_RANGE_START(name)[0]) \ + __attribute__((used, \ + weak, \ + __aligned__(SECTION_RANGE_ALIGNMENT(name)),\ + section(#__section "..rng.name."))) + +/** + * __SECTION_RANGE_END - Constructs the end of a section range + * + * @name: section range name + * @__section: ELF section to place section range into + * + * Constructs the end of a section range. You will typically not need + * to use this directly. + */ +#define __SECTION_RANGE_END(name, __section) \ + const __typeof__(SECTION_RANGE_START(name)[0]) \ + __attribute__((used, \ + __aligned__(SECTION_RANGE_ALIGNMENT(name)),\ + section(#__section "..rng.name.~"))) + +/** + * DEFINE_SECTION_RANGE - Defines a section range + * + * @name: section range name + * @section: ELF section name to place section range into + * + * Defines a section range, used for executable code. Section ranges are + * defined in the code that takes ownership and makes use of the section + * range. + */ +#define DEFINE_SECTION_RANGE(name, section) \ + DECLARE_LINUX_SECTION_RO(char, name); \ + __SECTION_RANGE_BEGIN(name, section) SECTION_RANGE_START(name)[0] = {};\ + __SECTION_RANGE_END(name, section) SECTION_RANGE_END(name)[0] = {} + +#endif /* __ASSEMBLY__ */ + +#endif /* _LINUX_RANGES_H */ -- 2.10.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html