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f0e1a0643a
linux-yocto/include/asm-generic/vmlinux.lds.h
Tejun Heo f0e1a0643a sched_ext: Implement BPF extensible scheduler class 
Implement a new scheduler class sched_ext (SCX), which allows scheduling
policies to be implemented as BPF programs to achieve the following:

1. Ease of experimentation and exploration: Enabling rapid iteration of new
   scheduling policies.

2. Customization: Building application-specific schedulers which implement
   policies that are not applicable to general-purpose schedulers.

3. Rapid scheduler deployments: Non-disruptive swap outs of scheduling
   policies in production environments.

sched_ext leverages BPF’s struct_ops feature to define a structure which
exports function callbacks and flags to BPF programs that wish to implement
scheduling policies. The struct_ops structure exported by sched_ext is
struct sched_ext_ops, and is conceptually similar to struct sched_class. The
role of sched_ext is to map the complex sched_class callbacks to the more
simple and ergonomic struct sched_ext_ops callbacks.

For more detailed discussion on the motivations and overview, please refer
to the cover letter.

Later patches will also add several example schedulers and documentation.

This patch implements the minimum core framework to enable implementation of
BPF schedulers. Subsequent patches will gradually add functionalities
including safety guarantee mechanisms, nohz and cgroup support.

include/linux/sched/ext.h defines struct sched_ext_ops. With the comment on
top, each operation should be self-explanatory. The followings are worth
noting:

- Both "sched_ext" and its shorthand "scx" are used. If the identifier
  already has "sched" in it, "ext" is used; otherwise, "scx".

- In sched_ext_ops, only .name is mandatory. Every operation is optional and
  if omitted a simple but functional default behavior is provided.

- A new policy constant SCHED_EXT is added and a task can select sched_ext
  by invoking sched_setscheduler(2) with the new policy constant. However,
  if the BPF scheduler is not loaded, SCHED_EXT is the same as SCHED_NORMAL
  and the task is scheduled by CFS. When the BPF scheduler is loaded, all
  tasks which have the SCHED_EXT policy are switched to sched_ext.

- To bridge the workflow imbalance between the scheduler core and
  sched_ext_ops callbacks, sched_ext uses simple FIFOs called dispatch
  queues (dsq's). By default, there is one global dsq (SCX_DSQ_GLOBAL), and
  one local per-CPU dsq (SCX_DSQ_LOCAL). SCX_DSQ_GLOBAL is provided for
  convenience and need not be used by a scheduler that doesn't require it.
  SCX_DSQ_LOCAL is the per-CPU FIFO that sched_ext pulls from when putting
  the next task on the CPU. The BPF scheduler can manage an arbitrary number
  of dsq's using scx_bpf_create_dsq() and scx_bpf_destroy_dsq().

- sched_ext guarantees system integrity no matter what the BPF scheduler
  does. To enable this, each task's ownership is tracked through
  p->scx.ops_state and all tasks are put on scx_tasks list. The disable path
  can always recover and revert all tasks back to CFS. See p->scx.ops_state
  and scx_tasks.

- A task is not tied to its rq while enqueued. This decouples CPU selection
  from queueing and allows sharing a scheduling queue across an arbitrary
  subset of CPUs. This adds some complexities as a task may need to be
  bounced between rq's right before it starts executing. See
  dispatch_to_local_dsq() and move_task_to_local_dsq().

- One complication that arises from the above weak association between task
  and rq is that synchronizing with dequeue() gets complicated as dequeue()
  may happen anytime while the task is enqueued and the dispatch path might
  need to release the rq lock to transfer the task. Solving this requires a
  bit of complexity. See the logic around p->scx.sticky_cpu and
  p->scx.ops_qseq.

- Both enable and disable paths are a bit complicated. The enable path
  switches all tasks without blocking to avoid issues which can arise from
  partially switched states (e.g. the switching task itself being starved).
  The disable path can't trust the BPF scheduler at all, so it also has to
  guarantee forward progress without blocking. See scx_ops_enable() and
  scx_ops_disable_workfn().

- When sched_ext is disabled, static_branches are used to shut down the
  entry points from hot paths.

v7: - scx_ops_bypass() was incorrectly and unnecessarily trying to grab
      scx_ops_enable_mutex which can lead to deadlocks in the disable path.
      Fixed.

    - Fixed TASK_DEAD handling bug in scx_ops_enable() path which could lead
      to use-after-free.

    - Consolidated per-cpu variable usages and other cleanups.

v6: - SCX_NR_ONLINE_OPS replaced with SCX_OPI_*_BEGIN/END so that multiple
      groups can be expressed. Later CPU hotplug operations are put into
      their own group.

    - SCX_OPS_DISABLING state is replaced with the new bypass mechanism
      which allows temporarily putting the system into simple FIFO
      scheduling mode bypassing the BPF scheduler. In addition to the shut
      down path, this will also be used to isolate the BPF scheduler across
      PM events. Enabling and disabling the bypass mode requires iterating
      all runnable tasks. rq->scx.runnable_list addition is moved from the
      later watchdog patch.

    - ops.prep_enable() is replaced with ops.init_task() and
      ops.enable/disable() are now called whenever the task enters and
      leaves sched_ext instead of when the task becomes schedulable on
      sched_ext and stops being so. A new operation - ops.exit_task() - is
      called when the task stops being schedulable on sched_ext.

    - scx_bpf_dispatch() can now be called from ops.select_cpu() too. This
      removes the need for communicating local dispatch decision made by
      ops.select_cpu() to ops.enqueue() via per-task storage.
      SCX_KF_SELECT_CPU is added to support the change.

    - SCX_TASK_ENQ_LOCAL which told the BPF scheudler that
      scx_select_cpu_dfl() wants the task to be dispatched to the local DSQ
      was removed. Instead, scx_bpf_select_cpu_dfl() now dispatches directly
      if it finds a suitable idle CPU. If such behavior is not desired,
      users can use scx_bpf_select_cpu_dfl() which returns the verdict in a
      bool out param.

    - scx_select_cpu_dfl() was mishandling WAKE_SYNC and could end up
      queueing many tasks on a local DSQ which makes tasks to execute in
      order while other CPUs stay idle which made some hackbench numbers
      really bad. Fixed.

    - The current state of sched_ext can now be monitored through files
      under /sys/sched_ext instead of /sys/kernel/debug/sched/ext. This is
      to enable monitoring on kernels which don't enable debugfs.

    - sched_ext wasn't telling BPF that ops.dispatch()'s @prev argument may
      be NULL and a BPF scheduler which derefs the pointer without checking
      could crash the kernel. Tell BPF. This is currently a bit ugly. A
      better way to annotate this is expected in the future.

    - scx_exit_info updated to carry pointers to message buffers instead of
      embedding them directly. This decouples buffer sizes from API so that
      they can be changed without breaking compatibility.

    - exit_code added to scx_exit_info. This is used to indicate different
      exit conditions on non-error exits and will be used to handle e.g. CPU
      hotplugs.

    - The patch "sched_ext: Allow BPF schedulers to switch all eligible
      tasks into sched_ext" is folded in and the interface is changed so
      that partial switching is indicated with a new ops flag
      %SCX_OPS_SWITCH_PARTIAL. This makes scx_bpf_switch_all() unnecessasry
      and in turn SCX_KF_INIT. ops.init() is now called with
      SCX_KF_SLEEPABLE.

    - Code reorganized so that only the parts necessary to integrate with
      the rest of the kernel are in the header files.

    - Changes to reflect the BPF and other kernel changes including the
      addition of bpf_sched_ext_ops.cfi_stubs.

v5: - To accommodate 32bit configs, p->scx.ops_state is now atomic_long_t
      instead of atomic64_t and scx_dsp_buf_ent.qseq which uses
      load_acquire/store_release is now unsigned long instead of u64.

    - Fix the bug where bpf_scx_btf_struct_access() was allowing write
      access to arbitrary fields.

    - Distinguish kfuncs which can be called from any sched_ext ops and from
      anywhere. e.g. scx_bpf_pick_idle_cpu() can now be called only from
      sched_ext ops.

    - Rename "type" to "kind" in scx_exit_info to make it easier to use on
      languages in which "type" is a reserved keyword.

    - Since cff9b2332a ("kernel/sched: Modify initial boot task idle
      setup"), PF_IDLE is not set on idle tasks which haven't been online
      yet which made scx_task_iter_next_filtered() include those idle tasks
      in iterations leading to oopses. Update scx_task_iter_next_filtered()
      to directly test p->sched_class against idle_sched_class instead of
      using is_idle_task() which tests PF_IDLE.

    - Other updates to match upstream changes such as adding const to
      set_cpumask() param and renaming check_preempt_curr() to
      wakeup_preempt().

v4: - SCHED_CHANGE_BLOCK replaced with the previous
      sched_deq_and_put_task()/sched_enq_and_set_tsak() pair. This is
      because upstream is adaopting a different generic cleanup mechanism.
      Once that lands, the code will be adapted accordingly.

    - task_on_scx() used to test whether a task should be switched into SCX,
      which is confusing. Renamed to task_should_scx(). task_on_scx() now
      tests whether a task is currently on SCX.

    - scx_has_idle_cpus is barely used anymore and replaced with direct
      check on the idle cpumask.

    - SCX_PICK_IDLE_CORE added and scx_pick_idle_cpu() improved to prefer
      fully idle cores.

    - ops.enable() now sees up-to-date p->scx.weight value.

    - ttwu_queue path is disabled for tasks on SCX to avoid confusing BPF
      schedulers expecting ->select_cpu() call.

    - Use cpu_smt_mask() instead of topology_sibling_cpumask() like the rest
      of the scheduler.

v3: - ops.set_weight() added to allow BPF schedulers to track weight changes
      without polling p->scx.weight.

    - move_task_to_local_dsq() was losing SCX-specific enq_flags when
      enqueueing the task on the target dsq because it goes through
      activate_task() which loses the upper 32bit of the flags. Carry the
      flags through rq->scx.extra_enq_flags.

    - scx_bpf_dispatch(), scx_bpf_pick_idle_cpu(), scx_bpf_task_running()
      and scx_bpf_task_cpu() now use the new KF_RCU instead of
      KF_TRUSTED_ARGS to make it easier for BPF schedulers to call them.

    - The kfunc helper access control mechanism implemented through
      sched_ext_entity.kf_mask is improved. Now SCX_CALL_OP*() is always
      used when invoking scx_ops operations.

v2: - balance_scx_on_up() is dropped. Instead, on UP, balance_scx() is
      called from put_prev_taks_scx() and pick_next_task_scx() as necessary.
      To determine whether balance_scx() should be called from
      put_prev_task_scx(), SCX_TASK_DEQD_FOR_SLEEP flag is added. See the
      comment in put_prev_task_scx() for details.

    - sched_deq_and_put_task() / sched_enq_and_set_task() sequences replaced
      with SCHED_CHANGE_BLOCK().

    - Unused all_dsqs list removed. This was a left-over from previous
      iterations.

    - p->scx.kf_mask is added to track and enforce which kfunc helpers are
      allowed. Also, init/exit sequences are updated to make some kfuncs
      always safe to call regardless of the current BPF scheduler state.
      Combined, this should make all the kfuncs safe.

    - BPF now supports sleepable struct_ops operations. Hacky workaround
      removed and operations and kfunc helpers are tagged appropriately.

    - BPF now supports bitmask / cpumask helpers. scx_bpf_get_idle_cpumask()
      and friends are added so that BPF schedulers can use the idle masks
      with the generic helpers. This replaces the hacky kfunc helpers added
      by a separate patch in V1.

    - CONFIG_SCHED_CLASS_EXT can no longer be enabled if SCHED_CORE is
      enabled. This restriction will be removed by a later patch which adds
      core-sched support.

    - Add MAINTAINERS entries and other misc changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Co-authored-by: David Vernet <dvernet@meta.com>
Acked-by: Josh Don <joshdon@google.com>
Acked-by: Hao Luo <haoluo@google.com>
Acked-by: Barret Rhoden <brho@google.com>
Cc: Andrea Righi <andrea.righi@canonical.com>
2024-06-18 10:09:17 -10:00

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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 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 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) \
*(__ext_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)
*/
#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*) \
*(.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) \
CODETAG_SECTIONS() \
LIKELY_PROFILE() \
BRANCH_PROFILE() \
TRACE_PRINTKS() \
BPF_RAW_TP() \
TRACEPOINT_STR() \
KUNIT_TABLE()
/*
* 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_stack = .; \
init_thread_union = .; \
init_stack = .; \
KEEP(*(.data..init_task)) \
KEEP(*(.data..init_thread_info)) \
. = __start_init_stack + THREAD_SIZE; \
__end_init_stack = .;
#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
/*
* Some symbol definitions will not exist yet during the first pass of the
* link, but are guaranteed to exist in the final link. Provide preliminary
* definitions that will be superseded in the final link to avoid having to
* rely on weak external linkage, which requires a GOT when used in position
* independent code.
*/
#define PRELIMINARY_SYMBOL_DEFINITIONS \
PROVIDE(kallsyms_addresses = .); \
PROVIDE(kallsyms_offsets = .); \
PROVIDE(kallsyms_names = .); \
PROVIDE(kallsyms_num_syms = .); \
PROVIDE(kallsyms_relative_base = .); \
PROVIDE(kallsyms_token_table = .); \
PROVIDE(kallsyms_token_index = .); \
PROVIDE(kallsyms_markers = .); \
PROVIDE(kallsyms_seqs_of_names = .);
/*
* Read only Data
*/
#define RO_DATA(align) \
. = ALIGN((align)); \
PRELIMINARY_SYMBOL_DEFINITIONS \
.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) \
} \
\
/* 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 \
*(.ref.text) \
*(.text.asan.* .text.tsan.*) \
MEM_KEEP(init.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_INIT_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.*) \
#define EXIT_TEXT \
*(.exit.text) \
*(.text.exit) \
#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 \
.orc_header : AT(ADDR(.orc_header) - LOAD_OFFSET) { \
BOUNDED_SECTION_BY(.orc_header, _orc_header) \
} \
. = 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)
/* Alignment must be consistent with (kunit_suite *) in include/kunit/test.h */
#define KUNIT_INIT_TABLE() \
. = ALIGN(8); \
BOUNDED_SECTION_POST_LABEL(.kunit_init_test_suites, \
__kunit_init_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://llvm.org/pr46478
*/
#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.*) \
*(.export_symbol) \
*(.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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