/* * Helper macros to support writing architecture specific * linker scripts. * * A minimal linker scripts has following content: * [This is a sample, architectures may have special requirements] * * OUTPUT_FORMAT(...) * OUTPUT_ARCH(...) * ENTRY(...) * SECTIONS * { * . = START; * __init_begin = .; * HEAD_TEXT_SECTION * INIT_TEXT_SECTION(PAGE_SIZE) * INIT_DATA_SECTION(...) * PERCPU_SECTION(CACHELINE_SIZE) * __init_end = .; * * _stext = .; * TEXT_SECTION = 0 * _etext = .; * * _sdata = .; * RO_DATA(PAGE_SIZE) * RW_DATA(...) * _edata = .; * * EXCEPTION_TABLE(...) * * BSS_SECTION(0, 0, 0) * _end = .; * * STABS_DEBUG * DWARF_DEBUG * ELF_DETAILS * * DISCARDS // must be the last * } * * [__init_begin, __init_end] is the init section that may be freed after init * // __init_begin and __init_end should be page aligned, so that we can * // free the whole .init memory * [_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 <asm-generic/codetag.lds.h> #ifndef LOAD_OFFSET #define LOAD_OFFSET … #endif /* * Only some architectures want to have the .notes segment visible in * a separate PT_NOTE ELF Program Header. When this happens, it needs * to be visible in both the kernel text's PT_LOAD and the PT_NOTE * Program Headers. In this case, though, the PT_LOAD needs to be made * the default again so that all the following sections don't also end * up in the PT_NOTE Program Header. */ #ifdef EMITS_PT_NOTE #define NOTES_HEADERS … #define NOTES_HEADERS_RESTORE … #else #define NOTES_HEADERS #define NOTES_HEADERS_RESTORE #endif /* * Some architectures have non-executable read-only exception tables. * They can be added to the RO_DATA segment by specifying their desired * alignment. */ #ifdef RO_EXCEPTION_TABLE_ALIGN #define RO_EXCEPTION_TABLE … #else #define RO_EXCEPTION_TABLE #endif /* Align . function alignment. */ #define ALIGN_FUNCTION() … /* * LD_DEAD_CODE_DATA_ELIMINATION option enables -fdata-sections, which * generates .data.identifier sections, which need to be pulled in with * .data. We don't want to pull in .data..other sections, which Linux * has defined. Same for text and bss. * * With LTO_CLANG, the linker also splits sections by default, so we need * these macros to combine the sections during the final link. * * RODATA_MAIN is not used because existing code already defines .rodata.x * sections to be brought in with rodata. */ #if defined(CONFIG_LD_DEAD_CODE_DATA_ELIMINATION) || defined(CONFIG_LTO_CLANG) #define TEXT_MAIN … #define DATA_MAIN … #define SDATA_MAIN … #define RODATA_MAIN … #define BSS_MAIN … #define SBSS_MAIN … #else #define TEXT_MAIN … #define DATA_MAIN … #define SDATA_MAIN … #define RODATA_MAIN … #define BSS_MAIN … #define SBSS_MAIN … #endif /* * GCC 4.5 and later have a 32 bytes section alignment for structures. * Except GCC 4.9, that feels the need to align on 64 bytes. */ #define STRUCT_ALIGNMENT … #define STRUCT_ALIGN() … /* * The order of the sched class addresses are important, as they are * used to determine the order of the priority of each sched class in * relation to each other. */ #define SCHED_DATA … /* The actual configuration determine if the init/exit sections * are handled as text/data or they can be discarded (which * often happens at runtime) */ #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_NO_PATCHABLE #define KEEP_PATCHABLE … #define PATCHABLE_DISCARDS #else #define KEEP_PATCHABLE #define PATCHABLE_DISCARDS … #endif #ifndef CONFIG_ARCH_SUPPORTS_CFI_CLANG /* * Simply points to ftrace_stub, but with the proper protocol. * Defined by the linker script in linux/vmlinux.lds.h */ #define FTRACE_STUB_HACK … #else #define FTRACE_STUB_HACK #endif #ifdef CONFIG_FTRACE_MCOUNT_RECORD /* * The ftrace call sites are logged to a section whose name depends on the * compiler option used. A given kernel image will only use one, AKA * FTRACE_CALLSITE_SECTION. We capture all of them here to avoid header * dependencies for FTRACE_CALLSITE_SECTION's definition. * * ftrace_ops_list_func will be defined as arch_ftrace_ops_list_func * as some archs will have a different prototype for that function * but ftrace_ops_list_func() will have a single prototype. */ #define MCOUNT_REC() … #else # ifdef CONFIG_FUNCTION_TRACER #define MCOUNT_REC … # else #define MCOUNT_REC … # endif #endif #define BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_) … #define BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_) … #define BOUNDED_SECTION_BY(_sec_, _label_) … #define BOUNDED_SECTION(_sec) … #define HEADERED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_, _HDR_) … #define HEADERED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_, _HDR_) … #define HEADERED_SECTION_BY(_sec_, _label_) … #define HEADERED_SECTION(_sec) … #ifdef CONFIG_TRACE_BRANCH_PROFILING #define LIKELY_PROFILE … #else #define LIKELY_PROFILE() … #endif #ifdef CONFIG_PROFILE_ALL_BRANCHES #define BRANCH_PROFILE … #else #define BRANCH_PROFILE() … #endif #ifdef CONFIG_KPROBES #define KPROBE_BLACKLIST() … #else #define KPROBE_BLACKLIST … #endif #ifdef CONFIG_FUNCTION_ERROR_INJECTION #define ERROR_INJECT_WHITELIST() … #else #define ERROR_INJECT_WHITELIST … #endif #ifdef CONFIG_EVENT_TRACING #define FTRACE_EVENTS() … #else #define FTRACE_EVENTS … #endif #ifdef CONFIG_TRACING #define TRACE_PRINTKS() … #define TRACEPOINT_STR() … #else #define TRACE_PRINTKS … #define TRACEPOINT_STR … #endif #ifdef CONFIG_FTRACE_SYSCALLS #define TRACE_SYSCALLS() … #else #define TRACE_SYSCALLS … #endif #ifdef CONFIG_BPF_EVENTS #define BPF_RAW_TP() … #else #define BPF_RAW_TP … #endif #ifdef CONFIG_SERIAL_EARLYCON #define EARLYCON_TABLE() … #else #define EARLYCON_TABLE … #endif #ifdef CONFIG_SECURITY #define LSM_TABLE() … #define EARLY_LSM_TABLE() … #else #define LSM_TABLE … #define EARLY_LSM_TABLE … #endif #define ___OF_TABLE(cfg, name) … #define __OF_TABLE(cfg, name) … #define OF_TABLE(cfg, name) … #define _OF_TABLE_0(name) … #define _OF_TABLE_1(name) … #define TIMER_OF_TABLES() … #define IRQCHIP_OF_MATCH_TABLE() … #define CLK_OF_TABLES() … #define RESERVEDMEM_OF_TABLES() … #define CPU_METHOD_OF_TABLES() … #define CPUIDLE_METHOD_OF_TABLES() … #ifdef CONFIG_ACPI #define ACPI_PROBE_TABLE(name) … #else #define ACPI_PROBE_TABLE … #endif #ifdef CONFIG_THERMAL #define THERMAL_TABLE(name) … #else #define THERMAL_TABLE … #endif #define KERNEL_DTB() … /* * .data section */ #define DATA_DATA … /* * Data section helpers */ #define NOSAVE_DATA … #define PAGE_ALIGNED_DATA(page_align) … #define READ_MOSTLY_DATA(align) … #define CACHELINE_ALIGNED_DATA(align) … #define INIT_TASK_DATA(align) … #define JUMP_TABLE_DATA … #ifdef CONFIG_HAVE_STATIC_CALL_INLINE #define STATIC_CALL_DATA … #else #define STATIC_CALL_DATA #endif /* * Allow architectures to handle ro_after_init data on their * own by defining an empty RO_AFTER_INIT_DATA. */ #ifndef RO_AFTER_INIT_DATA #define RO_AFTER_INIT_DATA … #endif /* * .kcfi_traps contains a list KCFI trap locations. */ #ifndef KCFI_TRAPS #ifdef CONFIG_ARCH_USES_CFI_TRAPS #define KCFI_TRAPS … #else #define KCFI_TRAPS #endif #endif /* * Read only Data */ #define RO_DATA(align) … /* * Non-instrumentable text section */ #define NOINSTR_TEXT … /* * .text section. Map to function alignment to avoid address changes * during second ld run in second ld pass when generating System.map * * TEXT_MAIN here will match .text.fixup and .text.unlikely if dead * code elimination is enabled, so these sections should be converted * to use ".." first. */ #define TEXT_TEXT … /* sched.text is aling to function alignment to secure we have same * address even at second ld pass when generating System.map */ #define SCHED_TEXT … /* spinlock.text is aling to function alignment to secure we have same * address even at second ld pass when generating System.map */ #define LOCK_TEXT … #define KPROBES_TEXT … #define ENTRY_TEXT … #define IRQENTRY_TEXT … #define SOFTIRQENTRY_TEXT … #define STATIC_CALL_TEXT … /* Section used for early init (in .S files) */ #define HEAD_TEXT … #define HEAD_TEXT_SECTION … /* * Exception table */ #define EXCEPTION_TABLE(align) … /* * .BTF */ #ifdef CONFIG_DEBUG_INFO_BTF #define BTF … #else #define BTF #endif /* * Init task */ #define INIT_TASK_DATA_SECTION(align) … #ifdef CONFIG_CONSTRUCTORS #define KERNEL_CTORS() … #else #define KERNEL_CTORS … #endif /* init and exit section handling */ #define INIT_DATA … #define INIT_TEXT … #define EXIT_DATA … \ #define EXIT_TEXT … \ #define EXIT_CALL … /* * bss (Block Started by Symbol) - uninitialized data * zeroed during startup */ #define SBSS(sbss_align) … /* * Allow archectures to redefine BSS_FIRST_SECTIONS to add extra * sections to the front of bss. */ #ifndef BSS_FIRST_SECTIONS #define BSS_FIRST_SECTIONS #endif #define BSS(bss_align) … /* * 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 … /* Stabs debugging sections. */ #define STABS_DEBUG … /* Required sections not related to debugging. */ #define ELF_DETAILS … #ifdef CONFIG_GENERIC_BUG #define BUG_TABLE … #else #define BUG_TABLE #endif #ifdef CONFIG_UNWINDER_ORC #define ORC_UNWIND_TABLE … #else #define ORC_UNWIND_TABLE #endif /* Built-in firmware blobs */ #ifdef CONFIG_FW_LOADER #define FW_LOADER_BUILT_IN_DATA … #else #define FW_LOADER_BUILT_IN_DATA #endif #ifdef CONFIG_PM_TRACE #define TRACEDATA … #else #define TRACEDATA #endif #ifdef CONFIG_PRINTK_INDEX #define PRINTK_INDEX … #else #define PRINTK_INDEX #endif /* * Discard .note.GNU-stack, which is emitted as PROGBITS by the compiler. * Otherwise, the type of .notes section would become PROGBITS instead of NOTES. * * Also, discard .note.gnu.property, otherwise it forces the notes section to * be 8-byte aligned which causes alignment mismatches with the kernel's custom * 4-byte aligned notes. */ #define NOTES … #define INIT_SETUP(initsetup_align) … #define INIT_CALLS_LEVEL(level) … \ #define INIT_CALLS … #define CON_INITCALL … #define NAMED_SECTION(name) … #define RUNTIME_CONST(t,x) … #define RUNTIME_CONST_VARIABLES … /* Alignment must be consistent with (kunit_suite *) in include/kunit/test.h */ #define KUNIT_TABLE() … /* Alignment must be consistent with (kunit_suite *) in include/kunit/test.h */ #define KUNIT_INIT_TABLE() … #ifdef CONFIG_BLK_DEV_INITRD #define INIT_RAM_FS … #else #define INIT_RAM_FS #endif /* * Memory encryption operates on a page basis. Since we need to clear * the memory encryption mask for this section, it needs to be aligned * on a page boundary and be a page-size multiple in length. * * Note: We use a separate section so that only this section gets * decrypted to avoid exposing more than we wish. */ #ifdef CONFIG_AMD_MEM_ENCRYPT #define PERCPU_DECRYPTED_SECTION … #else #define PERCPU_DECRYPTED_SECTION #endif /* * Default discarded sections. * * Some archs want to discard exit text/data at runtime rather than * link time due to cross-section references such as alt instructions, * bug table, eh_frame, etc. DISCARDS must be the last of output * section definitions so that such archs put those in earlier section * definitions. */ #ifdef RUNTIME_DISCARD_EXIT #define EXIT_DISCARDS #else #define EXIT_DISCARDS … #endif /* * Clang's -fprofile-arcs, -fsanitize=kernel-address, and * -fsanitize=thread produce unwanted sections (.eh_frame * and .init_array.*), but CONFIG_CONSTRUCTORS wants to * keep any .init_array.* sections. * https://llvm.org/pr46478 */ #ifdef CONFIG_UNWIND_TABLES #define DISCARD_EH_FRAME #else #define DISCARD_EH_FRAME … #endif #if defined(CONFIG_GCOV_KERNEL) || defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KCSAN) # ifdef CONFIG_CONSTRUCTORS #define SANITIZER_DISCARDS … # else #define SANITIZER_DISCARDS … # endif #else #define SANITIZER_DISCARDS #endif #define COMMON_DISCARDS … \ #define DISCARDS … /** * PERCPU_INPUT - the percpu input sections * @cacheline: cacheline size * * The core percpu section names and core symbols which do not rely * directly upon load addresses. * * @cacheline is used to align subsections to avoid false cacheline * sharing between subsections for different purposes. */ #define PERCPU_INPUT(cacheline) … /** * PERCPU_VADDR - define output section for percpu area * @cacheline: cacheline size * @vaddr: explicit base address (optional) * @phdr: destination PHDR (optional) * * Macro which expands to output section for percpu area. * * @cacheline is used to align subsections to avoid false cacheline * sharing between subsections for different purposes. * * If @vaddr is not blank, it specifies explicit base address and all * percpu symbols will be offset from the given address. If blank, * @vaddr always equals @laddr + LOAD_OFFSET. * * @phdr defines the output PHDR to use if not blank. Be warned that * output PHDR is sticky. If @phdr is specified, the next output * section in the linker script will go there too. @phdr should have * a leading colon. * * Note that this macros defines __per_cpu_load as an absolute symbol. * If there is no need to put the percpu section at a predetermined * address, use PERCPU_SECTION. */ #define PERCPU_VADDR(cacheline, vaddr, phdr) … /** * PERCPU_SECTION - define output section for percpu area, simple version * @cacheline: cacheline size * * Align to PAGE_SIZE and outputs output section for percpu area. This * macro doesn't manipulate @vaddr or @phdr and __per_cpu_load and * __per_cpu_start will be identical. * * This macro is equivalent to ALIGN(PAGE_SIZE); PERCPU_VADDR(@cacheline,,) * except that __per_cpu_load is defined as a relative symbol against * .data..percpu which is required for relocatable x86_32 configuration. */ #define PERCPU_SECTION(cacheline) … /* * 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 requirement of PAGE_ALIGNED_DATA. * * use 0 as page_align if page_aligned data is not used */ #define RW_DATA(cacheline, pagealigned, inittask) … \ #define INIT_TEXT_SECTION(inittext_align) … #define INIT_DATA_SECTION(initsetup_align) … #define BSS_SECTION(sbss_align, bss_align, stop_align) …