* [PATCH 0/2] vmlinux.lds.h tweaks
@ 2022-10-22 22:53 Jim Cromie
2022-10-22 22:53 ` [PATCH 1/2] vmlinux.lds.h: add BOUNDED_SECTION* macros Jim Cromie
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Jim Cromie @ 2022-10-22 22:53 UTC (permalink / raw)
To: linux-kernel, jbaron, gregkh
Cc: Jim Cromie, Suren Baghdasaryan, Kent Overstreet
hi Greg,
These 2 patches are "no functional change", but they are a simple step
towards de-duplicating the repetitive columms in the __dyndbg section.
For a DYNAMIC_DEBUG=y kernel with 5k pr_debugs/drm.debugs, the
footprint reduction should be ~100 KiB
Jim Cromie (2):
vmlinux.lds.h: add BOUNDED_SECTION* macros
vmlinux.lds.h: place optional header space in BOUNDED_SECTION
include/asm-generic/vmlinux.lds.h | 221 +++++++++++-------------------
1 file changed, 81 insertions(+), 140 deletions(-)
CC: Suren Baghdasaryan <surenb@google.com>
CC: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
--
2.37.3
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 1/2] vmlinux.lds.h: add BOUNDED_SECTION* macros
2022-10-22 22:53 [PATCH 0/2] vmlinux.lds.h tweaks Jim Cromie
@ 2022-10-22 22:53 ` Jim Cromie
2022-10-22 22:53 ` [PATCH 2/2] vmlinux.lds.h: add a KEEP .gnu.linkonce.##_name into BOUNDED_SECTION Jim Cromie
2022-10-22 22:53 ` [PATCH 2/2] vmlinux.lds.h: place optional header space in BOUNDED_SECTION Jim Cromie
2 siblings, 0 replies; 5+ messages in thread
From: Jim Cromie @ 2022-10-22 22:53 UTC (permalink / raw)
To: linux-kernel, jbaron, gregkh
Cc: Jim Cromie, Suren Baghdasaryan, Kent Overstreet
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 <surenb@google.com>
CC: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
Shall we bikeshed the names ?
---
include/asm-generic/vmlinux.lds.h | 219 +++++++++++-------------------
1 file changed, 79 insertions(+), 140 deletions(-)
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 \
--
2.37.3
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 2/2] vmlinux.lds.h: add a KEEP .gnu.linkonce.##_name into BOUNDED_SECTION
2022-10-22 22:53 [PATCH 0/2] vmlinux.lds.h tweaks Jim Cromie
2022-10-22 22:53 ` [PATCH 1/2] vmlinux.lds.h: add BOUNDED_SECTION* macros Jim Cromie
@ 2022-10-22 22:53 ` Jim Cromie
2022-10-22 22:53 ` [PATCH 2/2] vmlinux.lds.h: place optional header space in BOUNDED_SECTION Jim Cromie
2 siblings, 0 replies; 5+ messages in thread
From: Jim Cromie @ 2022-10-22 22:53 UTC (permalink / raw)
To: linux-kernel, jbaron, gregkh; +Cc: Jim Cromie
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 <jim.cromie@gmail.com>
---
? does this need a new name ? HEADERED_SECTION ?
---
include/asm-generic/vmlinux.lds.h | 2 ++
1 file changed, 2 insertions(+)
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_ = .;
--
2.37.3
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 2/2] vmlinux.lds.h: place optional header space in BOUNDED_SECTION
2022-10-22 22:53 [PATCH 0/2] vmlinux.lds.h tweaks Jim Cromie
2022-10-22 22:53 ` [PATCH 1/2] vmlinux.lds.h: add BOUNDED_SECTION* macros Jim Cromie
2022-10-22 22:53 ` [PATCH 2/2] vmlinux.lds.h: add a KEEP .gnu.linkonce.##_name into BOUNDED_SECTION Jim Cromie
@ 2022-10-22 22:53 ` Jim Cromie
2 siblings, 0 replies; 5+ messages in thread
From: Jim Cromie @ 2022-10-22 22:53 UTC (permalink / raw)
To: linux-kernel, jbaron, gregkh; +Cc: Jim Cromie
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 <jim.cromie@gmail.com>
---
? does this need a new name ? HEADERED_SECTION ?
---
include/asm-generic/vmlinux.lds.h | 2 ++
1 file changed, 2 insertions(+)
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_ = .;
--
2.37.3
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 1/2] vmlinux.lds.h: add BOUNDED_SECTION* macros
2022-10-22 22:56 [PATCH 0/2] RESEND vmlinux.lds.h tweaks Jim Cromie
@ 2022-10-22 22:56 ` Jim Cromie
0 siblings, 0 replies; 5+ messages in thread
From: Jim Cromie @ 2022-10-22 22:56 UTC (permalink / raw)
To: linux-kernel, jbaron, gregkh
Cc: Jim Cromie, Suren Baghdasaryan, Kent Overstreet
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 <surenb@google.com>
CC: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
Shall we bikeshed the names ?
---
include/asm-generic/vmlinux.lds.h | 219 +++++++++++-------------------
1 file changed, 79 insertions(+), 140 deletions(-)
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 \
--
2.37.3
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-10-22 22:56 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-10-22 22:53 [PATCH 0/2] vmlinux.lds.h tweaks Jim Cromie
2022-10-22 22:53 ` [PATCH 1/2] vmlinux.lds.h: add BOUNDED_SECTION* macros Jim Cromie
2022-10-22 22:53 ` [PATCH 2/2] vmlinux.lds.h: add a KEEP .gnu.linkonce.##_name into BOUNDED_SECTION Jim Cromie
2022-10-22 22:53 ` [PATCH 2/2] vmlinux.lds.h: place optional header space in BOUNDED_SECTION Jim Cromie
2022-10-22 22:56 [PATCH 0/2] RESEND vmlinux.lds.h tweaks Jim Cromie
2022-10-22 22:56 ` [PATCH 1/2] vmlinux.lds.h: add BOUNDED_SECTION* macros Jim Cromie
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