From 9b351be25360c5cedfb98b88d6dfd89327849e52 Mon Sep 17 00:00:00 2001 From: Jim Cromie Date: Sat, 22 Oct 2022 16:56:36 -0600 Subject: vmlinux.lds.h: add BOUNDED_SECTION* macros vmlinux.lds.h has ~45 occurrences of this general pattern: __start_foo = .; KEEP(*(foo)) __stop_foo = .; Reduce this pattern to a (group of 4) macros, and use them to reduce linecount. This was inspired by the codetag patchset. no functional change. CC: Suren Baghdasaryan CC: Kent Overstreet Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20221022225637.1406715-2-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman --- include/asm-generic/vmlinux.lds.h | 219 ++++++++++++++------------------------ 1 file changed, 79 insertions(+), 140 deletions(-) (limited to 'include/asm-generic') diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index c15de165ec8f..9f6352171f88 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -193,100 +193,99 @@ # endif #endif +#define BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _s_, _e_) \ + _s_##_label_ = .; \ + KEEP(*(_sec_)) \ + _e_##_label_ = .; + +#define BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _s_, _e_) \ + _label_##_s_ = .; \ + KEEP(*(_sec_)) \ + _label_##_e_ = .; + +#define BOUNDED_SECTION_BY(_sec_, _label_) \ + BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, __start, __stop) + +#define BOUNDED_SECTION(_sec) BOUNDED_SECTION_BY(_sec, _sec) + #ifdef CONFIG_TRACE_BRANCH_PROFILING -#define LIKELY_PROFILE() __start_annotated_branch_profile = .; \ - KEEP(*(_ftrace_annotated_branch)) \ - __stop_annotated_branch_profile = .; +#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() __start_branch_profile = .; \ - KEEP(*(_ftrace_branch)) \ - __stop_branch_profile = .; +#define BRANCH_PROFILE() \ + BOUNDED_SECTION_BY(_ftrace_branch, _branch_profile) #else #define BRANCH_PROFILE() #endif #ifdef CONFIG_KPROBES -#define KPROBE_BLACKLIST() . = ALIGN(8); \ - __start_kprobe_blacklist = .; \ - KEEP(*(_kprobe_blacklist)) \ - __stop_kprobe_blacklist = .; +#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(); \ - __start_error_injection_whitelist = .; \ - KEEP(*(_error_injection_whitelist)) \ - __stop_error_injection_whitelist = .; +#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); \ - __start_ftrace_events = .; \ - KEEP(*(_ftrace_events)) \ - __stop_ftrace_events = .; \ - __start_ftrace_eval_maps = .; \ - KEEP(*(_ftrace_eval_map)) \ - __stop_ftrace_eval_maps = .; +#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() __start___trace_bprintk_fmt = .; \ - KEEP(*(__trace_printk_fmt)) /* Trace_printk fmt' pointer */ \ - __stop___trace_bprintk_fmt = .; -#define TRACEPOINT_STR() __start___tracepoint_str = .; \ - KEEP(*(__tracepoint_str)) /* Trace_printk fmt' pointer */ \ - __stop___tracepoint_str = .; +#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); \ - __start_syscalls_metadata = .; \ - KEEP(*(__syscalls_metadata)) \ - __stop_syscalls_metadata = .; +#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(); \ - __start__bpf_raw_tp = .; \ - KEEP(*(__bpf_raw_tp_map)) \ - __stop__bpf_raw_tp = .; +#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); \ - __earlycon_table = .; \ - KEEP(*(__earlycon_table)) \ - __earlycon_table_end = .; +#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); \ - __start_lsm_info = .; \ - KEEP(*(.lsm_info.init)) \ - __end_lsm_info = .; -#define EARLY_LSM_TABLE() . = ALIGN(8); \ - __start_early_lsm_info = .; \ - KEEP(*(.early_lsm_info.init)) \ - __end_early_lsm_info = .; +#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() @@ -312,9 +311,8 @@ #ifdef CONFIG_ACPI #define ACPI_PROBE_TABLE(name) \ . = ALIGN(8); \ - __##name##_acpi_probe_table = .; \ - KEEP(*(__##name##_acpi_probe_table)) \ - __##name##_acpi_probe_table_end = .; + BOUNDED_SECTION_POST_LABEL(__##name##_acpi_probe_table, \ + __##name##_acpi_probe_table,, _end) #else #define ACPI_PROBE_TABLE(name) #endif @@ -322,9 +320,8 @@ #ifdef CONFIG_THERMAL #define THERMAL_TABLE(name) \ . = ALIGN(8); \ - __##name##_thermal_table = .; \ - KEEP(*(__##name##_thermal_table)) \ - __##name##_thermal_table_end = .; + BOUNDED_SECTION_POST_LABEL(__##name##_thermal_table, \ + __##name##_thermal_table,, _end) #else #define THERMAL_TABLE(name) #endif @@ -353,12 +350,8 @@ *(__tracepoints) \ /* implement dynamic printk debug */ \ . = ALIGN(8); \ - __start___dyndbg_classes = .; \ - KEEP(*(__dyndbg_classes)) \ - __stop___dyndbg_classes = .; \ - __start___dyndbg = .; \ - KEEP(*(__dyndbg)) \ - __stop___dyndbg = .; \ + BOUNDED_SECTION_BY(__dyndbg_classes, ___dyndbg_classes) \ + BOUNDED_SECTION_BY(__dyndbg, ___dyndbg) \ LIKELY_PROFILE() \ BRANCH_PROFILE() \ TRACE_PRINTKS() \ @@ -401,19 +394,13 @@ #define JUMP_TABLE_DATA \ . = ALIGN(8); \ - __start___jump_table = .; \ - KEEP(*(__jump_table)) \ - __stop___jump_table = .; + BOUNDED_SECTION_BY(__jump_table, ___jump_table) #ifdef CONFIG_HAVE_STATIC_CALL_INLINE #define STATIC_CALL_DATA \ . = ALIGN(8); \ - __start_static_call_sites = .; \ - KEEP(*(.static_call_sites)) \ - __stop_static_call_sites = .; \ - __start_static_call_tramp_key = .; \ - KEEP(*(.static_call_tramp_key)) \ - __stop_static_call_tramp_key = .; + 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 @@ -439,9 +426,7 @@ #ifdef CONFIG_ARCH_USES_CFI_TRAPS #define KCFI_TRAPS \ __kcfi_traps : AT(ADDR(__kcfi_traps) - LOAD_OFFSET) { \ - __start___kcfi_traps = .; \ - KEEP(*(.kcfi_traps)) \ - __stop___kcfi_traps = .; \ + BOUNDED_SECTION_BY(.kcfi_traps, ___kcfi_traps) \ } #else #define KCFI_TRAPS @@ -459,9 +444,7 @@ SCHED_DATA \ RO_AFTER_INIT_DATA /* Read only after init */ \ . = ALIGN(8); \ - __start___tracepoints_ptrs = .; \ - KEEP(*(__tracepoints_ptrs)) /* Tracepoints: pointer array */ \ - __stop___tracepoints_ptrs = .; \ + BOUNDED_SECTION_BY(__tracepoints_ptrs, ___tracepoints_ptrs) \ *(__tracepoints_strings)/* Tracepoints: strings */ \ } \ \ @@ -471,30 +454,14 @@ \ /* PCI quirks */ \ .pci_fixup : AT(ADDR(.pci_fixup) - LOAD_OFFSET) { \ - __start_pci_fixups_early = .; \ - KEEP(*(.pci_fixup_early)) \ - __end_pci_fixups_early = .; \ - __start_pci_fixups_header = .; \ - KEEP(*(.pci_fixup_header)) \ - __end_pci_fixups_header = .; \ - __start_pci_fixups_final = .; \ - KEEP(*(.pci_fixup_final)) \ - __end_pci_fixups_final = .; \ - __start_pci_fixups_enable = .; \ - KEEP(*(.pci_fixup_enable)) \ - __end_pci_fixups_enable = .; \ - __start_pci_fixups_resume = .; \ - KEEP(*(.pci_fixup_resume)) \ - __end_pci_fixups_resume = .; \ - __start_pci_fixups_resume_early = .; \ - KEEP(*(.pci_fixup_resume_early)) \ - __end_pci_fixups_resume_early = .; \ - __start_pci_fixups_suspend = .; \ - KEEP(*(.pci_fixup_suspend)) \ - __end_pci_fixups_suspend = .; \ - __start_pci_fixups_suspend_late = .; \ - KEEP(*(.pci_fixup_suspend_late)) \ - __end_pci_fixups_suspend_late = .; \ + 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 \ @@ -544,16 +511,12 @@ \ /* Built-in module parameters. */ \ __param : AT(ADDR(__param) - LOAD_OFFSET) { \ - __start___param = .; \ - KEEP(*(__param)) \ - __stop___param = .; \ + BOUNDED_SECTION_BY(__param, ___param) \ } \ \ /* Built-in module versions. */ \ __modver : AT(ADDR(__modver) - LOAD_OFFSET) { \ - __start___modver = .; \ - KEEP(*(__modver)) \ - __stop___modver = .; \ + BOUNDED_SECTION_BY(__modver, ___modver) \ } \ \ KCFI_TRAPS \ @@ -663,9 +626,7 @@ #define EXCEPTION_TABLE(align) \ . = ALIGN(align); \ __ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) { \ - __start___ex_table = .; \ - KEEP(*(__ex_table)) \ - __stop___ex_table = .; \ + BOUNDED_SECTION_BY(__ex_table, ___ex_table) \ } /* @@ -674,9 +635,7 @@ #ifdef CONFIG_DEBUG_INFO_BTF #define BTF \ .BTF : AT(ADDR(.BTF) - LOAD_OFFSET) { \ - __start_BTF = .; \ - KEEP(*(.BTF)) \ - __stop_BTF = .; \ + BOUNDED_SECTION_BY(.BTF, _BTF) \ } \ . = ALIGN(4); \ .BTF_ids : AT(ADDR(.BTF_ids) - LOAD_OFFSET) { \ @@ -853,9 +812,7 @@ #define BUG_TABLE \ . = ALIGN(8); \ __bug_table : AT(ADDR(__bug_table) - LOAD_OFFSET) { \ - __start___bug_table = .; \ - KEEP(*(__bug_table)) \ - __stop___bug_table = .; \ + BOUNDED_SECTION_BY(__bug_table, ___bug_table) \ } #else #define BUG_TABLE @@ -865,15 +822,11 @@ #define ORC_UNWIND_TABLE \ . = ALIGN(4); \ .orc_unwind_ip : AT(ADDR(.orc_unwind_ip) - LOAD_OFFSET) { \ - __start_orc_unwind_ip = .; \ - KEEP(*(.orc_unwind_ip)) \ - __stop_orc_unwind_ip = .; \ + BOUNDED_SECTION_BY(.orc_unwind_ip, _orc_unwind_ip) \ } \ . = ALIGN(2); \ .orc_unwind : AT(ADDR(.orc_unwind) - LOAD_OFFSET) { \ - __start_orc_unwind = .; \ - KEEP(*(.orc_unwind)) \ - __stop_orc_unwind = .; \ + BOUNDED_SECTION_BY(.orc_unwind, _orc_unwind) \ } \ text_size = _etext - _stext; \ . = ALIGN(4); \ @@ -891,9 +844,7 @@ #ifdef CONFIG_FW_LOADER #define FW_LOADER_BUILT_IN_DATA \ .builtin_fw : AT(ADDR(.builtin_fw) - LOAD_OFFSET) ALIGN(8) { \ - __start_builtin_fw = .; \ - KEEP(*(.builtin_fw)) \ - __end_builtin_fw = .; \ + BOUNDED_SECTION_PRE_LABEL(.builtin_fw, _builtin_fw, __start, __end) \ } #else #define FW_LOADER_BUILT_IN_DATA @@ -903,9 +854,7 @@ #define TRACEDATA \ . = ALIGN(4); \ .tracedata : AT(ADDR(.tracedata) - LOAD_OFFSET) { \ - __tracedata_start = .; \ - KEEP(*(.tracedata)) \ - __tracedata_end = .; \ + BOUNDED_SECTION_POST_LABEL(.tracedata, __tracedata, _start, _end) \ } #else #define TRACEDATA @@ -914,9 +863,7 @@ #ifdef CONFIG_PRINTK_INDEX #define PRINTK_INDEX \ .printk_index : AT(ADDR(.printk_index) - LOAD_OFFSET) { \ - __start_printk_index = .; \ - *(.printk_index) \ - __stop_printk_index = .; \ + BOUNDED_SECTION_BY(.printk_index, _printk_index) \ } #else #define PRINTK_INDEX @@ -924,17 +871,13 @@ #define NOTES \ .notes : AT(ADDR(.notes) - LOAD_OFFSET) { \ - __start_notes = .; \ - KEEP(*(.note.*)) \ - __stop_notes = .; \ + BOUNDED_SECTION_BY(.note.*, _notes) \ } NOTES_HEADERS \ NOTES_HEADERS_RESTORE #define INIT_SETUP(initsetup_align) \ . = ALIGN(initsetup_align); \ - __setup_start = .; \ - KEEP(*(.init.setup)) \ - __setup_end = .; + BOUNDED_SECTION_POST_LABEL(.init.setup, __setup, _start, _end) #define INIT_CALLS_LEVEL(level) \ __initcall##level##_start = .; \ @@ -956,16 +899,12 @@ __initcall_end = .; #define CON_INITCALL \ - __con_initcall_start = .; \ - KEEP(*(.con_initcall.init)) \ - __con_initcall_end = .; + 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); \ - __kunit_suites_start = .; \ - KEEP(*(.kunit_test_suites)) \ - __kunit_suites_end = .; + BOUNDED_SECTION_POST_LABEL(.kunit_test_suites, __kunit_suites, _start, _end) #ifdef CONFIG_BLK_DEV_INITRD #define INIT_RAM_FS \ -- cgit v1.2.3 From 2f465b921bb8ff97025017e05f6c7a7a1f6a5749 Mon Sep 17 00:00:00 2001 From: Jim Cromie Date: Sat, 22 Oct 2022 16:56:37 -0600 Subject: vmlinux.lds.h: place optional header space in BOUNDED_SECTION Extend recently added BOUNDED_SECTION(_name) macro by adding a KEEP(*(.gnu.linkonce.##_name)) before the KEEP(*(_name)). This does nothing by itself, vmlinux is the same before and after this patch. But if a developer adds a .gnu.linkonce.foo record, that record is placed in the front of the section, where it can be used as a header for the table. The intent is to create an up-link to another organizing struct, from where related tables can be referenced. And since every item in a table has a known offset from its header, that same offset can be used to fetch records from the related tables. By itself, this doesnt gain much, unless maybe the pattern of access is to scan 1 or 2 fields in each fat record, but with 2 16 bit .map* fields added, we could de-duplicate 2 related tables. The use case here is struct _ddebug, which has 3 pointers (function, file, module) with substantial repetition; respectively 53%, 90%, and the module column is fully recoverable after dynamic_debug_init() splits the table into a linked list of "module" chunks. On a DYNAMIC_DEBUG=y kernel with 5k pr_debugs, the memory savings should be ~100 KiB. Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20221022225637.1406715-3-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman --- include/asm-generic/vmlinux.lds.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/asm-generic') diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 9f6352171f88..b3ca56ac163f 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -195,11 +195,13 @@ #define BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _s_, _e_) \ _s_##_label_ = .; \ + KEEP(*(.gnu.linkonce.##_sec_)) \ KEEP(*(_sec_)) \ _e_##_label_ = .; #define BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _s_, _e_) \ _label_##_s_ = .; \ + KEEP(*(.gnu.linkonce.##_sec_)) \ KEEP(*(_sec_)) \ _label_##_e_ = .; -- cgit v1.2.3 From 435d6b6564568b82ec74ee7d4d0bcb1f24ccb5f5 Mon Sep 17 00:00:00 2001 From: Jim Cromie Date: Thu, 17 Nov 2022 10:16:32 -0700 Subject: vmlinux.lds.h: fix BOUNDED_SECTION_(PRE|POST)_LABEL macros Commit 2f465b921bb8 ("vmlinux.lds.h: place optional header space in BOUNDED_SECTION") added BOUNDED_SECTION_(PRE|POST)_LABEL macros, encapsulating the basic boilerplate to KEEP/pack records into a section, and to mark the begin and end of the section with linker-symbols. But it tried to do extra, adding KEEP(*(.gnu.linkonce.##_sec_)) to optionally reserve a header record in front of the data. It wrongly placed the KEEP after the linker-symbol starting the section, so if a header was added, it would wind up in the data. Moving the KEEP to the "correct" place proved brittle, and too clever by half. The obvious safe fix is to remove the KEEP and restore the plain old boilerplate. The header can be added later, with separate macros. Also, the macro var-names: _s_, _e_ are nearly invisible, change them to more obvious names: _BEGIN_, _END_ Fixes: 2f465b921bb8 ("vmlinux.lds.h: place optional header space in BOUNDED_SECTION") Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20221117171633.923628-2-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman --- include/asm-generic/vmlinux.lds.h | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) (limited to 'include/asm-generic') diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index b3ca56ac163f..c17f94785253 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -193,17 +193,15 @@ # endif #endif -#define BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _s_, _e_) \ - _s_##_label_ = .; \ - KEEP(*(.gnu.linkonce.##_sec_)) \ +#define BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_) \ + _BEGIN_##_label_ = .; \ KEEP(*(_sec_)) \ - _e_##_label_ = .; + _END_##_label_ = .; -#define BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _s_, _e_) \ - _label_##_s_ = .; \ - KEEP(*(.gnu.linkonce.##_sec_)) \ +#define BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_) \ + _label_##_BEGIN_ = .; \ KEEP(*(_sec_)) \ - _label_##_e_ = .; + _label_##_END_ = .; #define BOUNDED_SECTION_BY(_sec_, _label_) \ BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, __start, __stop) -- cgit v1.2.3 From 1d926e259d8f8195fdfaeea7951149001894b473 Mon Sep 17 00:00:00 2001 From: Jim Cromie Date: Thu, 17 Nov 2022 10:16:33 -0700 Subject: vmlinux.lds.h: add HEADERED_SECTION_* macros These macros elaborate on BOUNDED_SECTION_(PRE|POST)_LABEL macros, prepending an optional KEEP(.gnu.linkonce##_sec_) reservation, and a linker-symbol to address it. This allows a developer to define a header struct (which must fit with the section's base struct-type), and could contain: 1- fields whose value is common to the entire set of data-records. This allows the header & data structs to specialize, complement each other, and shrink. 2- an uplink pointer to an organizing struct which refs other related/sub data-tables header record is addressable via the extern'd header linker-symbol Once the linker-symbols created by the macro are ref'd extern in code, that code can compute a record's index (ptr - start) in the "primary" table, then use it to index into the related/sub tables. Adding a primary.map_* field foreach sub-table would then allow deduplication and remapping of that sub-table. This is aimed at dyndbg's struct _ddebug __dyndbg[] section, whose 3 columns: function, file, module are 50%, 90%, 100% redundant. The module column is fully recoverable after dynamic_debug_init() saves it to each ddebug_table.module as the builtin __dyndbg[] table is parsed. Given that those 3 columns use 24/56 of a _ddebug record, a dyndbg=y kernel with ~5k callsites could reduce kernel memory substantially. Returning that memory to the kernel buddy-allocator? is then possible. Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20221117171633.923628-3-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman --- include/asm-generic/vmlinux.lds.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'include/asm-generic') diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index c17f94785253..c9a475a30803 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -208,6 +208,21 @@ #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) -- cgit v1.2.3