diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-generic/vmlinux.lds.h | 231 |
1 files changed, 224 insertions, 7 deletions
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 3edb1149974..fba42236e94 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -1,4 +1,58 @@ -#include <linux/section-names.h> +/* + * Helper macros to support writing architecture specific + * linker scripts. + * + * A minimal linker scripts has following content: + * [This is a sample, architectures may have special requiriements] + * + * OUTPUT_FORMAT(...) + * OUTPUT_ARCH(...) + * ENTRY(...) + * SECTIONS + * { + * . = START; + * __init_begin = .; + * HEAD_SECTION + * INIT_TEXT_SECTION(PAGE_SIZE) + * INIT_DATA_SECTION(...) + * PERCPU(PAGE_SIZE) + * __init_end = .; + * + * _stext = .; + * TEXT_SECTION = 0 + * _etext = .; + * + * _sdata = .; + * RO_DATA_SECTION(PAGE_SIZE) + * RW_DATA_SECTION(...) + * _edata = .; + * + * EXCEPTION_TABLE(...) + * NOTES + * + * __bss_start = .; + * BSS_SECTION(0, 0) + * __bss_stop = .; + * _end = .; + * + * /DISCARD/ : { + * EXIT_TEXT + * EXIT_DATA + * *(.exitcall.exit) + * } + * STABS_DEBUG + * DWARF_DEBUG + * } + * + * [__init_begin, __init_end] is the init section that may be freed after init + * [_stext, _etext] is the text section + * [_sdata, _edata] is the data section + * + * Some of the included output section have their own set of constants. + * Examples are: [__initramfs_start, __initramfs_end] for initramfs and + * [__nosave_begin, __nosave_end] for the nosave data + */ + #include <linux/section-names.h> #ifndef LOAD_OFFSET #define LOAD_OFFSET 0 @@ -116,7 +170,36 @@ FTRACE_EVENTS() \ TRACE_SYSCALLS() -#define RO_DATA(align) \ +/* + * Data section helpers + */ +#define NOSAVE_DATA \ + . = ALIGN(PAGE_SIZE); \ + VMLINUX_SYMBOL(__nosave_begin) = .; \ + *(.data.nosave) \ + . = ALIGN(PAGE_SIZE); \ + VMLINUX_SYMBOL(__nosave_end) = .; + +#define PAGE_ALIGNED_DATA(page_align) \ + . = ALIGN(page_align); \ + *(.data.page_aligned) + +#define READ_MOSTLY_DATA(align) \ + . = ALIGN(align); \ + *(.data.read_mostly) + +#define CACHELINE_ALIGNED_DATA(align) \ + . = ALIGN(align); \ + *(.data.cacheline_aligned) + +#define INIT_TASK(align) \ + . = ALIGN(align); \ + *(.data.init_task) + +/* + * Read only Data + */ +#define RO_DATA_SECTION(align) \ . = ALIGN((align)); \ .rodata : AT(ADDR(.rodata) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start_rodata) = .; \ @@ -270,9 +353,10 @@ } \ . = ALIGN((align)); -/* RODATA provided for backward compatibility. +/* RODATA & RO_DATA provided for backward compatibility. * All archs are supposed to use RO_DATA() */ -#define RODATA RO_DATA(4096) +#define RODATA RO_DATA_SECTION(4096) +#define RO_DATA(align) RO_DATA_SECTION(align) #define SECURITY_INIT \ .security_initcall.init : AT(ADDR(.security_initcall.init) - LOAD_OFFSET) { \ @@ -332,6 +416,31 @@ /* Section used for early init (in .S files) */ #define HEAD_TEXT *(HEAD_TEXT_SECTION) +#define HEAD_SECTION \ + .head.text : AT(ADDR(.head.text) - LOAD_OFFSET) { \ + HEAD_TEXT \ + } + +/* + * Exception table + */ +#define EXCEPTION_TABLE(align) \ + . = ALIGN(align); \ + __ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) { \ + VMLINUX_SYMBOL(__start___ex_table) = .; \ + *(__ex_table) \ + VMLINUX_SYMBOL(__stop___ex_table) = .; \ + } + +/* + * Init task + */ +#define INIT_TASK_DATA(align) \ + . = ALIGN(align); \ + .data.init_task : { \ + INIT_TASK \ + } + /* init and exit section handling */ #define INIT_DATA \ *(.init.data) \ @@ -364,9 +473,32 @@ CPU_DISCARD(exit.text) \ MEM_DISCARD(exit.text) - /* DWARF debug sections. - Symbols in the DWARF debugging sections are relative to - the beginning of the section so we begin them at 0. */ +/* + * bss (Block Started by Symbol) - uninitialized data + * zeroed during startup + */ +#define SBSS \ + .sbss : AT(ADDR(.sbss) - LOAD_OFFSET) { \ + *(.sbss) \ + *(.scommon) \ + } + +#define BSS(bss_align) \ + . = ALIGN(bss_align); \ + .bss : AT(ADDR(.bss) - LOAD_OFFSET) { \ + VMLINUX_SYMBOL(__bss_start) = .; \ + *(.bss.page_aligned) \ + *(.dynbss) \ + *(.bss) \ + *(COMMON) \ + VMLINUX_SYMBOL(__bss_stop) = .; \ + } + +/* + * DWARF debug sections. + * Symbols in the DWARF debugging sections are relative to + * the beginning of the section so we begin them at 0. + */ #define DWARF_DEBUG \ /* DWARF 1 */ \ .debug 0 : { *(.debug) } \ @@ -433,6 +565,12 @@ VMLINUX_SYMBOL(__stop_notes) = .; \ } +#define INIT_SETUP(initsetup_align) \ + . = ALIGN(initsetup_align); \ + VMLINUX_SYMBOL(__setup_start) = .; \ + *(.init.setup) \ + VMLINUX_SYMBOL(__setup_end) = .; + #define INITCALLS \ *(.initcallearly.init) \ VMLINUX_SYMBOL(__early_initcall_end) = .; \ @@ -454,6 +592,31 @@ *(.initcall7.init) \ *(.initcall7s.init) +#define INIT_CALLS \ + VMLINUX_SYMBOL(__initcall_start) = .; \ + INITCALLS \ + VMLINUX_SYMBOL(__initcall_end) = .; + +#define CON_INITCALL \ + VMLINUX_SYMBOL(__con_initcall_start) = .; \ + *(.con_initcall.init) \ + VMLINUX_SYMBOL(__con_initcall_end) = .; + +#define SECURITY_INITCALL \ + VMLINUX_SYMBOL(__security_initcall_start) = .; \ + *(.security_initcall.init) \ + VMLINUX_SYMBOL(__security_initcall_end) = .; + +#ifdef CONFIG_BLK_DEV_INITRD +#define INIT_RAM_FS \ + . = ALIGN(PAGE_SIZE); \ + VMLINUX_SYMBOL(__initramfs_start) = .; \ + *(.init.ramfs) \ + VMLINUX_SYMBOL(__initramfs_end) = .; +#else +#define INITRAMFS +#endif + /** * PERCPU_VADDR - define output section for percpu area * @vaddr: explicit base address (optional) @@ -510,3 +673,57 @@ *(.data.percpu.shared_aligned) \ VMLINUX_SYMBOL(__per_cpu_end) = .; \ } + + +/* + * Definition of the high level *_SECTION macros + * They will fit only a subset of the architectures + */ + + +/* + * Writeable data. + * All sections are combined in a single .data section. + * The sections following CONSTRUCTORS are arranged so their + * typical alignment matches. + * A cacheline is typical/always less than a PAGE_SIZE so + * the sections that has this restriction (or similar) + * is located before the ones requiring PAGE_SIZE alignment. + * NOSAVE_DATA starts and ends with a PAGE_SIZE alignment which + * matches the requirment of PAGE_ALIGNED_DATA. + * +/* use 0 as page_align if page_aligned data is not used */ +#define RW_DATA_SECTION(cacheline, nosave, pagealigned, inittask) \ + . = ALIGN(PAGE_SIZE); \ + .data : AT(ADDR(.data) - LOAD_OFFSET) { \ + INIT_TASK(inittask) \ + CACHELINE_ALIGNED_DATA(cacheline) \ + READ_MOSTLY_DATA(cacheline) \ + DATA_DATA \ + CONSTRUCTORS \ + NOSAVE_DATA(nosave) \ + PAGE_ALIGNED_DATA(pagealigned) \ + } + +#define INIT_TEXT_SECTION(inittext_align) \ + . = ALIGN(inittext_align); \ + .init.text : AT(ADDR(.init.text) - LOAD_OFFSET) { \ + VMLINUX_SYMBOL(_sinittext) = .; \ + INIT_TEXT \ + VMLINUX_SYMBOL(_einittext) = .; \ + } + +#define INIT_DATA_SECTION(initsetup_align) \ + .init.data : AT(ADDR(.init.data) - LOAD_OFFSET) { \ + INIT_DATA \ + INIT_SETUP(initsetup_align) \ + INIT_CALLS \ + CON_INITCALL \ + SECURITY_INITCALL \ + INIT_RAM_FS \ + } + +#define BSS_SECTION(sbss_align, bss_align) \ + SBSS \ + BSS(bss_align) \ + . = ALIGN(4); \ |