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linux-stable/include/asm-generic/vmlinux.lds.h
Josh Poimboeuf f7ba52f302 vmlinux.lds.h: Discard .note.gnu.property section 
When tooling reads ELF notes, it assumes each note entry is aligned to
the value listed in the .note section header's sh_addralign field.

The kernel-created ELF notes in the .note.Linux and .note.Xen sections
are aligned to 4 bytes.  This causes the toolchain to set those
sections' sh_addralign values to 4.

On the other hand, the GCC-created .note.gnu.property section has an
sh_addralign value of 8 for some reason, despite being based on struct
Elf32_Nhdr which only needs 4-byte alignment.

When the mismatched input sections get linked together into the vmlinux
.notes output section, the higher alignment "wins", resulting in an
sh_addralign of 8, which confuses tooling.  For example:

  $ readelf -n .tmp_vmlinux.btf
  ...
  readelf: .tmp_vmlinux.btf: Warning: note with invalid namesz and/or descsz found at offset 0x170
  readelf: .tmp_vmlinux.btf: Warning:  type: 0x4, namesize: 0x006e6558, descsize: 0x00008801, alignment: 8

In this case readelf thinks there's alignment padding where there is
none, so it starts reading an ELF note in the middle.

With newer toolchains (e.g., latest Fedora Rawhide), a similar mismatch
triggers a build failure when combined with CONFIG_X86_KERNEL_IBT:

  btf_encoder__encode: btf__dedup failed!
  Failed to encode BTF
  libbpf: failed to find '.BTF' ELF section in vmlinux
  FAILED: load BTF from vmlinux: No data available
  make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255

This latter error was caused by pahole crashing when it encountered the
corrupt .notes section.  This crash has been fixed in dwarves version
1.25.  As Tianyi Liu describes:

  "Pahole reads .notes to look for LINUX_ELFNOTE_BUILD_LTO. When LTO is
   enabled, pahole needs to call cus__merge_and_process_cu to merge
   compile units, at which point there should only be one unspecified
   type (used to represent some compilation information) in the global
   context.

   However, when the kernel is compiled without LTO, if pahole calls
   cus__merge_and_process_cu due to alignment issues with notes,
   multiple unspecified types may appear after merging the cus, and
   older versions of pahole only support up to one. This is why pahole
   1.24 crashes, while newer versions support multiple. However, the
   latest version of pahole still does not solve the problem of
   incorrect LTO recognition, so compiling the kernel may be slower
   than normal."

Even with the newer pahole, the note section misaligment issue still
exists and pahole is misinterpreting the LTO note.  Fix it by discarding
the .note.gnu.property section.  While GNU properties are important for
user space (and VDSO), they don't seem to have any use for vmlinux.

(In fact, they're already getting (inadvertently) stripped from vmlinux
when CONFIG_DEBUG_INFO_BTF is enabled.  The BTF data is extracted from
vmlinux.o with "objcopy --only-section=.BTF" into .btf.vmlinux.bin.o.
That file doesn't have .note.gnu.property, so when it gets modified and
linked back into the main object, the linker automatically strips it
(see "How GNU properties are merged" in the ld man page).)

Reported-by: Daniel Xu <dxu@dxuuu.xyz>
Link: https://lkml.kernel.org/bpf/57830c30-cd77-40cf-9cd1-3bb608aa602e@app.fastmail.com
Debugged-by: Tianyi Liu <i.pear@outlook.com>
Suggested-by: Joan Bruguera Micó <joanbrugueram@gmail.com>
Link: https://lore.kernel.org/r/20230418214925.ay3jpf2zhw75kgmd@treble
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-05-16 06:30:50 -07:00

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/*
* 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_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
*/
#ifndef LOAD_OFFSET
#define LOAD_OFFSET 0
#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 :text :note
#define NOTES_HEADERS_RESTORE __restore_ph : { *(.__restore_ph) } :text
#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 EXCEPTION_TABLE(RO_EXCEPTION_TABLE_ALIGN)
#else
#define RO_EXCEPTION_TABLE
#endif
/* Align . function alignment. */
#define ALIGN_FUNCTION() . = ALIGN(CONFIG_FUNCTION_ALIGNMENT)
/*
* 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 .text .text.[0-9a-zA-Z_]*
#define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data..L* .data..compoundliteral* .data.$__unnamed_* .data.$L*
#define SDATA_MAIN .sdata .sdata.[0-9a-zA-Z_]*
#define RODATA_MAIN .rodata .rodata.[0-9a-zA-Z_]* .rodata..L*
#define BSS_MAIN .bss .bss.[0-9a-zA-Z_]* .bss..compoundliteral*
#define SBSS_MAIN .sbss .sbss.[0-9a-zA-Z_]*
#else
#define TEXT_MAIN .text
#define DATA_MAIN .data
#define SDATA_MAIN .sdata
#define RODATA_MAIN .rodata
#define BSS_MAIN .bss
#define SBSS_MAIN .sbss
#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 32
#define STRUCT_ALIGN() . = ALIGN(STRUCT_ALIGNMENT)
/*
* 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 \
STRUCT_ALIGN(); \
__sched_class_highest = .; \
*(__stop_sched_class) \
*(__dl_sched_class) \
*(__rt_sched_class) \
*(__fair_sched_class) \
*(__idle_sched_class) \
__sched_class_lowest = .;
/* The actual configuration determine if the init/exit sections
* are handled as text/data or they can be discarded (which
* often happens at runtime)
*/
#ifdef CONFIG_HOTPLUG_CPU
#define CPU_KEEP(sec) *(.cpu##sec)
#define CPU_DISCARD(sec)
#else
#define CPU_KEEP(sec)
#define CPU_DISCARD(sec) *(.cpu##sec)
#endif
#if defined(CONFIG_MEMORY_HOTPLUG)
#define MEM_KEEP(sec) *(.mem##sec)
#define MEM_DISCARD(sec)
#else
#define MEM_KEEP(sec)
#define MEM_DISCARD(sec) *(.mem##sec)
#endif
#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
#define KEEP_PATCHABLE KEEP(*(__patchable_function_entries))
#define PATCHABLE_DISCARDS
#else
#define KEEP_PATCHABLE
#define PATCHABLE_DISCARDS *(__patchable_function_entries)
#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 ftrace_stub_graph = ftrace_stub;
#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() . = ALIGN(8); \
__start_mcount_loc = .; \
KEEP(*(__mcount_loc)) \
KEEP_PATCHABLE \
__stop_mcount_loc = .; \
FTRACE_STUB_HACK \
ftrace_ops_list_func = arch_ftrace_ops_list_func;
#else
# ifdef CONFIG_FUNCTION_TRACER
# define MCOUNT_REC() FTRACE_STUB_HACK \
ftrace_ops_list_func = arch_ftrace_ops_list_func;
# else
# define MCOUNT_REC()
# endif
#endif
#define BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_) \
_BEGIN_##_label_ = .; \
KEEP(*(_sec_)) \
_END_##_label_ = .;
#define BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_) \
_label_##_BEGIN_ = .; \
KEEP(*(_sec_)) \
_label_##_END_ = .;
#define BOUNDED_SECTION_BY(_sec_, _label_) \
BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, __start, __stop)
#define BOUNDED_SECTION(_sec) BOUNDED_SECTION_BY(_sec, _sec)
#define HEADERED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_, _HDR_) \
_HDR_##_label_ = .; \
KEEP(*(.gnu.linkonce.##_sec_)) \
BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_)
#define HEADERED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_, _HDR_) \
_label_##_HDR_ = .; \
KEEP(*(.gnu.linkonce.##_sec_)) \
BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_)
#define HEADERED_SECTION_BY(_sec_, _label_) \
HEADERED_SECTION_PRE_LABEL(_sec_, _label_, __start, __stop)
#define HEADERED_SECTION(_sec) HEADERED_SECTION_BY(_sec, _sec)
#ifdef CONFIG_TRACE_BRANCH_PROFILING
#define LIKELY_PROFILE() \
BOUNDED_SECTION_BY(_ftrace_annotated_branch, _annotated_branch_profile)
#else
#define LIKELY_PROFILE()
#endif
#ifdef CONFIG_PROFILE_ALL_BRANCHES
#define BRANCH_PROFILE() \
BOUNDED_SECTION_BY(_ftrace_branch, _branch_profile)
#else
#define BRANCH_PROFILE()
#endif
#ifdef CONFIG_KPROBES
#define KPROBE_BLACKLIST() \
. = ALIGN(8); \
BOUNDED_SECTION(_kprobe_blacklist)
#else
#define KPROBE_BLACKLIST()
#endif
#ifdef CONFIG_FUNCTION_ERROR_INJECTION
#define ERROR_INJECT_WHITELIST() \
STRUCT_ALIGN(); \
BOUNDED_SECTION(_error_injection_whitelist)
#else
#define ERROR_INJECT_WHITELIST()
#endif
#ifdef CONFIG_EVENT_TRACING
#define FTRACE_EVENTS() \
. = ALIGN(8); \
BOUNDED_SECTION(_ftrace_events) \
BOUNDED_SECTION_BY(_ftrace_eval_map, _ftrace_eval_maps)
#else
#define FTRACE_EVENTS()
#endif
#ifdef CONFIG_TRACING
#define TRACE_PRINTKS() BOUNDED_SECTION_BY(__trace_printk_fmt, ___trace_bprintk_fmt)
#define TRACEPOINT_STR() BOUNDED_SECTION_BY(__tracepoint_str, ___tracepoint_str)
#else
#define TRACE_PRINTKS()
#define TRACEPOINT_STR()
#endif
#ifdef CONFIG_FTRACE_SYSCALLS
#define TRACE_SYSCALLS() \
. = ALIGN(8); \
BOUNDED_SECTION_BY(__syscalls_metadata, _syscalls_metadata)
#else
#define TRACE_SYSCALLS()
#endif
#ifdef CONFIG_BPF_EVENTS
#define BPF_RAW_TP() STRUCT_ALIGN(); \
BOUNDED_SECTION_BY(__bpf_raw_tp_map, __bpf_raw_tp)
#else
#define BPF_RAW_TP()
#endif
#ifdef CONFIG_SERIAL_EARLYCON
#define EARLYCON_TABLE() \
. = ALIGN(8); \
BOUNDED_SECTION_POST_LABEL(__earlycon_table, __earlycon_table, , _end)
#else
#define EARLYCON_TABLE()
#endif
#ifdef CONFIG_SECURITY
#define LSM_TABLE() \
. = ALIGN(8); \
BOUNDED_SECTION_PRE_LABEL(.lsm_info.init, _lsm_info, __start, __end)
#define EARLY_LSM_TABLE() \
. = ALIGN(8); \
BOUNDED_SECTION_PRE_LABEL(.early_lsm_info.init, _early_lsm_info, __start, __end)
#else
#define LSM_TABLE()
#define EARLY_LSM_TABLE()
#endif
#define ___OF_TABLE(cfg, name) _OF_TABLE_##cfg(name)
#define __OF_TABLE(cfg, name) ___OF_TABLE(cfg, name)
#define OF_TABLE(cfg, name) __OF_TABLE(IS_ENABLED(cfg), name)
#define _OF_TABLE_0(name)
#define _OF_TABLE_1(name) \
. = ALIGN(8); \
__##name##_of_table = .; \
KEEP(*(__##name##_of_table)) \
KEEP(*(__##name##_of_table_end))
#define TIMER_OF_TABLES() OF_TABLE(CONFIG_TIMER_OF, timer)
#define IRQCHIP_OF_MATCH_TABLE() OF_TABLE(CONFIG_IRQCHIP, irqchip)
#define CLK_OF_TABLES() OF_TABLE(CONFIG_COMMON_CLK, clk)
#define RESERVEDMEM_OF_TABLES() OF_TABLE(CONFIG_OF_RESERVED_MEM, reservedmem)
#define CPU_METHOD_OF_TABLES() OF_TABLE(CONFIG_SMP, cpu_method)
#define CPUIDLE_METHOD_OF_TABLES() OF_TABLE(CONFIG_CPU_IDLE, cpuidle_method)
#ifdef CONFIG_ACPI
#define ACPI_PROBE_TABLE(name) \
. = ALIGN(8); \
BOUNDED_SECTION_POST_LABEL(__##name##_acpi_probe_table, \
__##name##_acpi_probe_table,, _end)
#else
#define ACPI_PROBE_TABLE(name)
#endif
#ifdef CONFIG_THERMAL
#define THERMAL_TABLE(name) \
. = ALIGN(8); \
BOUNDED_SECTION_POST_LABEL(__##name##_thermal_table, \
__##name##_thermal_table,, _end)
#else
#define THERMAL_TABLE(name)
#endif
#define KERNEL_DTB() \
STRUCT_ALIGN(); \
__dtb_start = .; \
KEEP(*(.dtb.init.rodata)) \
__dtb_end = .;
/*
* .data section
*/
#define DATA_DATA \
*(.xiptext) \
*(DATA_MAIN) \
*(.data..decrypted) \
*(.ref.data) \
*(.data..shared_aligned) /* percpu related */ \
MEM_KEEP(init.data*) \
MEM_KEEP(exit.data*) \
*(.data.unlikely) \
__start_once = .; \
*(.data.once) \
__end_once = .; \
STRUCT_ALIGN(); \
*(__tracepoints) \
/* implement dynamic printk debug */ \
. = ALIGN(8); \
BOUNDED_SECTION_BY(__dyndbg_classes, ___dyndbg_classes) \
BOUNDED_SECTION_BY(__dyndbg, ___dyndbg) \
LIKELY_PROFILE() \
BRANCH_PROFILE() \
TRACE_PRINTKS() \
BPF_RAW_TP() \
TRACEPOINT_STR()
/*
* Data section helpers
*/
#define NOSAVE_DATA \
. = ALIGN(PAGE_SIZE); \
__nosave_begin = .; \
*(.data..nosave) \
. = ALIGN(PAGE_SIZE); \
__nosave_end = .;
#define PAGE_ALIGNED_DATA(page_align) \
. = ALIGN(page_align); \
*(.data..page_aligned) \
. = ALIGN(page_align);
#define READ_MOSTLY_DATA(align) \
. = ALIGN(align); \
*(.data..read_mostly) \
. = ALIGN(align);
#define CACHELINE_ALIGNED_DATA(align) \
. = ALIGN(align); \
*(.data..cacheline_aligned)
#define INIT_TASK_DATA(align) \
. = ALIGN(align); \
__start_init_task = .; \
init_thread_union = .; \
init_stack = .; \
KEEP(*(.data..init_task)) \
KEEP(*(.data..init_thread_info)) \
. = __start_init_task + THREAD_SIZE; \
__end_init_task = .;
#define JUMP_TABLE_DATA \
. = ALIGN(8); \
BOUNDED_SECTION_BY(__jump_table, ___jump_table)
#ifdef CONFIG_HAVE_STATIC_CALL_INLINE
#define STATIC_CALL_DATA \
. = ALIGN(8); \
BOUNDED_SECTION_BY(.static_call_sites, _static_call_sites) \
BOUNDED_SECTION_BY(.static_call_tramp_key, _static_call_tramp_key)
#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 \
. = ALIGN(8); \
__start_ro_after_init = .; \
*(.data..ro_after_init) \
JUMP_TABLE_DATA \
STATIC_CALL_DATA \
__end_ro_after_init = .;
#endif
/*
* .kcfi_traps contains a list KCFI trap locations.
*/
#ifndef KCFI_TRAPS
#ifdef CONFIG_ARCH_USES_CFI_TRAPS
#define KCFI_TRAPS \
__kcfi_traps : AT(ADDR(__kcfi_traps) - LOAD_OFFSET) { \
BOUNDED_SECTION_BY(.kcfi_traps, ___kcfi_traps) \
}
#else
#define KCFI_TRAPS
#endif
#endif
/*
* Read only Data
*/
#define RO_DATA(align) \
. = ALIGN((align)); \
.rodata : AT(ADDR(.rodata) - LOAD_OFFSET) { \
__start_rodata = .; \
*(.rodata) *(.rodata.*) \
SCHED_DATA \
RO_AFTER_INIT_DATA /* Read only after init */ \
. = ALIGN(8); \
BOUNDED_SECTION_BY(__tracepoints_ptrs, ___tracepoints_ptrs) \
*(__tracepoints_strings)/* Tracepoints: strings */ \
} \
\
.rodata1 : AT(ADDR(.rodata1) - LOAD_OFFSET) { \
*(.rodata1) \
} \
\
/* PCI quirks */ \
.pci_fixup : AT(ADDR(.pci_fixup) - LOAD_OFFSET) { \
BOUNDED_SECTION_PRE_LABEL(.pci_fixup_early, _pci_fixups_early, __start, __end) \
BOUNDED_SECTION_PRE_LABEL(.pci_fixup_header, _pci_fixups_header, __start, __end) \
BOUNDED_SECTION_PRE_LABEL(.pci_fixup_final, _pci_fixups_final, __start, __end) \
BOUNDED_SECTION_PRE_LABEL(.pci_fixup_enable, _pci_fixups_enable, __start, __end) \
BOUNDED_SECTION_PRE_LABEL(.pci_fixup_resume, _pci_fixups_resume, __start, __end) \
BOUNDED_SECTION_PRE_LABEL(.pci_fixup_suspend, _pci_fixups_suspend, __start, __end) \
BOUNDED_SECTION_PRE_LABEL(.pci_fixup_resume_early, _pci_fixups_resume_early, __start, __end) \
BOUNDED_SECTION_PRE_LABEL(.pci_fixup_suspend_late, _pci_fixups_suspend_late, __start, __end) \
} \
\
FW_LOADER_BUILT_IN_DATA \
TRACEDATA \
\
PRINTK_INDEX \
\
/* Kernel symbol table: Normal symbols */ \
__ksymtab : AT(ADDR(__ksymtab) - LOAD_OFFSET) { \
__start___ksymtab = .; \
KEEP(*(SORT(___ksymtab+*))) \
__stop___ksymtab = .; \
} \
\
/* Kernel symbol table: GPL-only symbols */ \
__ksymtab_gpl : AT(ADDR(__ksymtab_gpl) - LOAD_OFFSET) { \
__start___ksymtab_gpl = .; \
KEEP(*(SORT(___ksymtab_gpl+*))) \
__stop___ksymtab_gpl = .; \
} \
\
/* Kernel symbol table: Normal symbols */ \
__kcrctab : AT(ADDR(__kcrctab) - LOAD_OFFSET) { \
__start___kcrctab = .; \
KEEP(*(SORT(___kcrctab+*))) \
__stop___kcrctab = .; \
} \
\
/* Kernel symbol table: GPL-only symbols */ \
__kcrctab_gpl : AT(ADDR(__kcrctab_gpl) - LOAD_OFFSET) { \
__start___kcrctab_gpl = .; \
KEEP(*(SORT(___kcrctab_gpl+*))) \
__stop___kcrctab_gpl = .; \
} \
\
/* Kernel symbol table: strings */ \
__ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) { \
*(__ksymtab_strings) \
} \
\
/* __*init sections */ \
__init_rodata : AT(ADDR(__init_rodata) - LOAD_OFFSET) { \
*(.ref.rodata) \
MEM_KEEP(init.rodata) \
MEM_KEEP(exit.rodata) \
} \
\
/* Built-in module parameters. */ \
__param : AT(ADDR(__param) - LOAD_OFFSET) { \
BOUNDED_SECTION_BY(__param, ___param) \
} \
\
/* Built-in module versions. */ \
__modver : AT(ADDR(__modver) - LOAD_OFFSET) { \
BOUNDED_SECTION_BY(__modver, ___modver) \
} \
\
KCFI_TRAPS \
\
RO_EXCEPTION_TABLE \
NOTES \
BTF \
\
. = ALIGN((align)); \
__end_rodata = .;
/*
* Non-instrumentable text section
*/
#define NOINSTR_TEXT \
ALIGN_FUNCTION(); \
__noinstr_text_start = .; \
*(.noinstr.text) \
__cpuidle_text_start = .; \
*(.cpuidle.text) \
__cpuidle_text_end = .; \
__noinstr_text_end = .;
/*
* .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 \
ALIGN_FUNCTION(); \
*(.text.hot .text.hot.*) \
*(TEXT_MAIN .text.fixup) \
*(.text.unlikely .text.unlikely.*) \
*(.text.unknown .text.unknown.*) \
NOINSTR_TEXT \
*(.text..refcount) \
*(.ref.text) \
*(.text.asan.* .text.tsan.*) \
MEM_KEEP(init.text*) \
MEM_KEEP(exit.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 \
ALIGN_FUNCTION(); \
__sched_text_start = .; \
*(.sched.text) \
__sched_text_end = .;
/* 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 \
ALIGN_FUNCTION(); \
__lock_text_start = .; \
*(.spinlock.text) \
__lock_text_end = .;
#define KPROBES_TEXT \
ALIGN_FUNCTION(); \
__kprobes_text_start = .; \
*(.kprobes.text) \
__kprobes_text_end = .;
#define ENTRY_TEXT \
ALIGN_FUNCTION(); \
__entry_text_start = .; \
*(.entry.text) \
__entry_text_end = .;
#define IRQENTRY_TEXT \
ALIGN_FUNCTION(); \
__irqentry_text_start = .; \
*(.irqentry.text) \
__irqentry_text_end = .;
#define SOFTIRQENTRY_TEXT \
ALIGN_FUNCTION(); \
__softirqentry_text_start = .; \
*(.softirqentry.text) \
__softirqentry_text_end = .;
#define STATIC_CALL_TEXT \
ALIGN_FUNCTION(); \
__static_call_text_start = .; \
*(.static_call.text) \
__static_call_text_end = .;
/* Section used for early init (in .S files) */
#define HEAD_TEXT KEEP(*(.head.text))
#define HEAD_TEXT_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) { \
BOUNDED_SECTION_BY(__ex_table, ___ex_table) \
}
/*
* .BTF
*/
#ifdef CONFIG_DEBUG_INFO_BTF
#define BTF \
.BTF : AT(ADDR(.BTF) - LOAD_OFFSET) { \
BOUNDED_SECTION_BY(.BTF, _BTF) \
} \
. = ALIGN(4); \
.BTF_ids : AT(ADDR(.BTF_ids) - LOAD_OFFSET) { \
*(.BTF_ids) \
}
#else
#define BTF
#endif
/*
* Init task
*/
#define INIT_TASK_DATA_SECTION(align) \
. = ALIGN(align); \
.data..init_task : AT(ADDR(.data..init_task) - LOAD_OFFSET) { \
INIT_TASK_DATA(align) \
}
#ifdef CONFIG_CONSTRUCTORS
#define KERNEL_CTORS() . = ALIGN(8); \
__ctors_start = .; \
KEEP(*(SORT(.ctors.*))) \
KEEP(*(.ctors)) \
KEEP(*(SORT(.init_array.*))) \
KEEP(*(.init_array)) \
__ctors_end = .;
#else
#define KERNEL_CTORS()
#endif
/* init and exit section handling */
#define INIT_DATA \
KEEP(*(SORT(___kentry+*))) \
*(.init.data init.data.*) \
MEM_DISCARD(init.data*) \
KERNEL_CTORS() \
MCOUNT_REC() \
*(.init.rodata .init.rodata.*) \
FTRACE_EVENTS() \
TRACE_SYSCALLS() \
KPROBE_BLACKLIST() \
ERROR_INJECT_WHITELIST() \
MEM_DISCARD(init.rodata) \
CLK_OF_TABLES() \
RESERVEDMEM_OF_TABLES() \
TIMER_OF_TABLES() \
CPU_METHOD_OF_TABLES() \
CPUIDLE_METHOD_OF_TABLES() \
KERNEL_DTB() \
IRQCHIP_OF_MATCH_TABLE() \
ACPI_PROBE_TABLE(irqchip) \
ACPI_PROBE_TABLE(timer) \
THERMAL_TABLE(governor) \
EARLYCON_TABLE() \
LSM_TABLE() \
EARLY_LSM_TABLE() \
KUNIT_TABLE()
#define INIT_TEXT \
*(.init.text .init.text.*) \
*(.text.startup) \
MEM_DISCARD(init.text*)
#define EXIT_DATA \
*(.exit.data .exit.data.*) \
*(.fini_array .fini_array.*) \
*(.dtors .dtors.*) \
MEM_DISCARD(exit.data*) \
MEM_DISCARD(exit.rodata*)
#define EXIT_TEXT \
*(.exit.text) \
*(.text.exit) \
MEM_DISCARD(exit.text)
#define EXIT_CALL \
*(.exitcall.exit)
/*
* bss (Block Started by Symbol) - uninitialized data
* zeroed during startup
*/
#define SBSS(sbss_align) \
. = ALIGN(sbss_align); \
.sbss : AT(ADDR(.sbss) - LOAD_OFFSET) { \
*(.dynsbss) \
*(SBSS_MAIN) \
*(.scommon) \
}
/*
* 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) \
. = ALIGN(bss_align); \
.bss : AT(ADDR(.bss) - LOAD_OFFSET) { \
BSS_FIRST_SECTIONS \
. = ALIGN(PAGE_SIZE); \
*(.bss..page_aligned) \
. = ALIGN(PAGE_SIZE); \
*(.dynbss) \
*(BSS_MAIN) \
*(COMMON) \
}
/*
* 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) } \
.line 0 : { *(.line) } \
/* GNU DWARF 1 extensions */ \
.debug_srcinfo 0 : { *(.debug_srcinfo) } \
.debug_sfnames 0 : { *(.debug_sfnames) } \
/* DWARF 1.1 and DWARF 2 */ \
.debug_aranges 0 : { *(.debug_aranges) } \
.debug_pubnames 0 : { *(.debug_pubnames) } \
/* DWARF 2 */ \
.debug_info 0 : { *(.debug_info \
.gnu.linkonce.wi.*) } \
.debug_abbrev 0 : { *(.debug_abbrev) } \
.debug_line 0 : { *(.debug_line) } \
.debug_frame 0 : { *(.debug_frame) } \
.debug_str 0 : { *(.debug_str) } \
.debug_loc 0 : { *(.debug_loc) } \
.debug_macinfo 0 : { *(.debug_macinfo) } \
.debug_pubtypes 0 : { *(.debug_pubtypes) } \
/* DWARF 3 */ \
.debug_ranges 0 : { *(.debug_ranges) } \
/* SGI/MIPS DWARF 2 extensions */ \
.debug_weaknames 0 : { *(.debug_weaknames) } \
.debug_funcnames 0 : { *(.debug_funcnames) } \
.debug_typenames 0 : { *(.debug_typenames) } \
.debug_varnames 0 : { *(.debug_varnames) } \
/* GNU DWARF 2 extensions */ \
.debug_gnu_pubnames 0 : { *(.debug_gnu_pubnames) } \
.debug_gnu_pubtypes 0 : { *(.debug_gnu_pubtypes) } \
/* DWARF 4 */ \
.debug_types 0 : { *(.debug_types) } \
/* DWARF 5 */ \
.debug_addr 0 : { *(.debug_addr) } \
.debug_line_str 0 : { *(.debug_line_str) } \
.debug_loclists 0 : { *(.debug_loclists) } \
.debug_macro 0 : { *(.debug_macro) } \
.debug_names 0 : { *(.debug_names) } \
.debug_rnglists 0 : { *(.debug_rnglists) } \
.debug_str_offsets 0 : { *(.debug_str_offsets) }
/* Stabs debugging sections. */
#define STABS_DEBUG \
.stab 0 : { *(.stab) } \
.stabstr 0 : { *(.stabstr) } \
.stab.excl 0 : { *(.stab.excl) } \
.stab.exclstr 0 : { *(.stab.exclstr) } \
.stab.index 0 : { *(.stab.index) } \
.stab.indexstr 0 : { *(.stab.indexstr) }
/* Required sections not related to debugging. */
#define ELF_DETAILS \
.comment 0 : { *(.comment) } \
.symtab 0 : { *(.symtab) } \
.strtab 0 : { *(.strtab) } \
.shstrtab 0 : { *(.shstrtab) }
#ifdef CONFIG_GENERIC_BUG
#define BUG_TABLE \
. = ALIGN(8); \
__bug_table : AT(ADDR(__bug_table) - LOAD_OFFSET) { \
BOUNDED_SECTION_BY(__bug_table, ___bug_table) \
}
#else
#define BUG_TABLE
#endif
#ifdef CONFIG_UNWINDER_ORC
#define ORC_UNWIND_TABLE \
. = ALIGN(4); \
.orc_unwind_ip : AT(ADDR(.orc_unwind_ip) - LOAD_OFFSET) { \
BOUNDED_SECTION_BY(.orc_unwind_ip, _orc_unwind_ip) \
} \
. = ALIGN(2); \
.orc_unwind : AT(ADDR(.orc_unwind) - LOAD_OFFSET) { \
BOUNDED_SECTION_BY(.orc_unwind, _orc_unwind) \
} \
text_size = _etext - _stext; \
. = ALIGN(4); \
.orc_lookup : AT(ADDR(.orc_lookup) - LOAD_OFFSET) { \
orc_lookup = .; \
. += (((text_size + LOOKUP_BLOCK_SIZE - 1) / \
LOOKUP_BLOCK_SIZE) + 1) * 4; \
orc_lookup_end = .; \
}
#else
#define ORC_UNWIND_TABLE
#endif
/* Built-in firmware blobs */
#ifdef CONFIG_FW_LOADER
#define FW_LOADER_BUILT_IN_DATA \
.builtin_fw : AT(ADDR(.builtin_fw) - LOAD_OFFSET) ALIGN(8) { \
BOUNDED_SECTION_PRE_LABEL(.builtin_fw, _builtin_fw, __start, __end) \
}
#else
#define FW_LOADER_BUILT_IN_DATA
#endif
#ifdef CONFIG_PM_TRACE
#define TRACEDATA \
. = ALIGN(4); \
.tracedata : AT(ADDR(.tracedata) - LOAD_OFFSET) { \
BOUNDED_SECTION_POST_LABEL(.tracedata, __tracedata, _start, _end) \
}
#else
#define TRACEDATA
#endif
#ifdef CONFIG_PRINTK_INDEX
#define PRINTK_INDEX \
.printk_index : AT(ADDR(.printk_index) - LOAD_OFFSET) { \
BOUNDED_SECTION_BY(.printk_index, _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 \
/DISCARD/ : { \
*(.note.GNU-stack) \
*(.note.gnu.property) \
} \
.notes : AT(ADDR(.notes) - LOAD_OFFSET) { \
BOUNDED_SECTION_BY(.note.*, _notes) \
} NOTES_HEADERS \
NOTES_HEADERS_RESTORE
#define INIT_SETUP(initsetup_align) \
. = ALIGN(initsetup_align); \
BOUNDED_SECTION_POST_LABEL(.init.setup, __setup, _start, _end)
#define INIT_CALLS_LEVEL(level) \
__initcall##level##_start = .; \
KEEP(*(.initcall##level##.init)) \
KEEP(*(.initcall##level##s.init)) \
#define INIT_CALLS \
__initcall_start = .; \
KEEP(*(.initcallearly.init)) \
INIT_CALLS_LEVEL(0) \
INIT_CALLS_LEVEL(1) \
INIT_CALLS_LEVEL(2) \
INIT_CALLS_LEVEL(3) \
INIT_CALLS_LEVEL(4) \
INIT_CALLS_LEVEL(5) \
INIT_CALLS_LEVEL(rootfs) \
INIT_CALLS_LEVEL(6) \
INIT_CALLS_LEVEL(7) \
__initcall_end = .;
#define CON_INITCALL \
BOUNDED_SECTION_POST_LABEL(.con_initcall.init, __con_initcall, _start, _end)
/* Alignment must be consistent with (kunit_suite *) in include/kunit/test.h */
#define KUNIT_TABLE() \
. = ALIGN(8); \
BOUNDED_SECTION_POST_LABEL(.kunit_test_suites, __kunit_suites, _start, _end)
#ifdef CONFIG_BLK_DEV_INITRD
#define INIT_RAM_FS \
. = ALIGN(4); \
__initramfs_start = .; \
KEEP(*(.init.ramfs)) \
. = ALIGN(8); \
KEEP(*(.init.ramfs.info))
#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 \
. = ALIGN(PAGE_SIZE); \
*(.data..percpu..decrypted) \
. = ALIGN(PAGE_SIZE);
#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 \
EXIT_TEXT \
EXIT_DATA
#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://bugs.llvm.org/show_bug.cgi?id=46478
*/
#ifdef CONFIG_UNWIND_TABLES
#define DISCARD_EH_FRAME
#else
#define DISCARD_EH_FRAME *(.eh_frame)
#endif
#if defined(CONFIG_GCOV_KERNEL) || defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KCSAN)
# ifdef CONFIG_CONSTRUCTORS
# define SANITIZER_DISCARDS \
DISCARD_EH_FRAME
# else
# define SANITIZER_DISCARDS \
*(.init_array) *(.init_array.*) \
DISCARD_EH_FRAME
# endif
#else
# define SANITIZER_DISCARDS
#endif
#define COMMON_DISCARDS \
SANITIZER_DISCARDS \
PATCHABLE_DISCARDS \
*(.discard) \
*(.discard.*) \
*(.modinfo) \
/* ld.bfd warns about .gnu.version* even when not emitted */ \
*(.gnu.version*) \
#define DISCARDS \
/DISCARD/ : { \
EXIT_DISCARDS \
EXIT_CALL \
COMMON_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) \
__per_cpu_start = .; \
*(.data..percpu..first) \
. = ALIGN(PAGE_SIZE); \
*(.data..percpu..page_aligned) \
. = ALIGN(cacheline); \
*(.data..percpu..read_mostly) \
. = ALIGN(cacheline); \
*(.data..percpu) \
*(.data..percpu..shared_aligned) \
PERCPU_DECRYPTED_SECTION \
__per_cpu_end = .;
/**
* 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) \
__per_cpu_load = .; \
.data..percpu vaddr : AT(__per_cpu_load - LOAD_OFFSET) { \
PERCPU_INPUT(cacheline) \
} phdr \
. = __per_cpu_load + SIZEOF(.data..percpu);
/**
* 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) \
. = ALIGN(PAGE_SIZE); \
.data..percpu : AT(ADDR(.data..percpu) - LOAD_OFFSET) { \
__per_cpu_load = .; \
PERCPU_INPUT(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) \
. = ALIGN(PAGE_SIZE); \
.data : AT(ADDR(.data) - LOAD_OFFSET) { \
INIT_TASK_DATA(inittask) \
NOSAVE_DATA \
PAGE_ALIGNED_DATA(pagealigned) \
CACHELINE_ALIGNED_DATA(cacheline) \
READ_MOSTLY_DATA(cacheline) \
DATA_DATA \
CONSTRUCTORS \
} \
BUG_TABLE \
#define INIT_TEXT_SECTION(inittext_align) \
. = ALIGN(inittext_align); \
.init.text : AT(ADDR(.init.text) - LOAD_OFFSET) { \
_sinittext = .; \
INIT_TEXT \
_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 \
INIT_RAM_FS \
}
#define BSS_SECTION(sbss_align, bss_align, stop_align) \
. = ALIGN(sbss_align); \
__bss_start = .; \
SBSS(sbss_align) \
BSS(bss_align) \
. = ALIGN(stop_align); \
__bss_stop = .;
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