kbuild: thin archives and gc-sections updates
Subsystems (2)
cover kbuild: thin archives and gc-sections updates
Hi,
Here are a couple of updates for the new build processes. I think these could go in 4.9 because nobody has started using them seriously yet, but on the other hand that is also a reason they can probably wait until 4.10.
Thanks,
Nick
Nicholas Piggin (2):
kbuild: thin archives for multi-y targets
kbuild: keep data tables through dead code elimination
include/asm-generic/vmlinux.lds.h | 68 +++++++++++++++++++-------------------- scripts/Makefile.build | 13 ++++++-- 2 files changed, 44 insertions(+), 37 deletions(-)
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2.9.3
PATCH 1/2 kbuild: thin archives for multi-y targets
THIN_ARCHIVES builds archives for built-in.o targets, have it build multi-y targets as archives as well.
This saves another ~15% of the size of intermediate artifacts in the build tree. After this patch, the linker is only used in final link, and special cases like vdsos.
Signed-off-by Nicholas Piggin <[email protected]>
--- scripts/Makefile.build | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)
scripts/Makefile.build +10 -3
@@ -514,11 +514,18 @@ $($(subst $(obj)/,,$(@:.o=-objs))) \ $($(subst $(obj)/,,$(@:.o=-y))) \ $($(subst $(obj)/,,$(@:.o=-m)))), $^) -quiet_cmd_link_multi-y = LD $@ -cmd_link_multi-y = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis) +cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis) + +ifdef CONFIG_THIN_ARCHIVES + quiet_cmd_link_multi-y = AR $@ + cmd_link_multi-y = rm -f $@; $(AR) rcST$(KBUILD_ARFLAGS) $@ $(link_multi_deps) +else + quiet_cmd_link_multi-y = LD $@ + cmd_link_multi-y = $(cmd_link_multi-link) +endif quiet_cmd_link_multi-m = LD [M] $@ -cmd_link_multi-m = $(cmd_link_multi-y) +cmd_link_multi-m = $(cmd_link_multi-link) $(multi-used-y): FORCE $(call if_changed,link_multi-y)
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2.9.3
PATCH 2/2 kbuild: keep data tables through dead code elimination
In reply to Nicholas PigginWhen CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is enabled we must ensure that we still keep various programatically-accessed tables.
[npiggin: Fold Paul's patches into one, and add a few more tables.
diff symbol tables of allyesconfig with/without -gc-sections shows up lost tables quite easily.]
Signed-off-by Paul Burton <[email protected]>
Signed-off-by Nicholas Piggin <[email protected]>
--- include/asm-generic/vmlinux.lds.h | 68 +++++++++++++++++++-------------------- 1 file changed, 34 insertions(+), 34 deletions(-)
include/asm-generic/vmlinux.lds.h +34 -34
@@ -114,7 +114,7 @@#ifdef CONFIG_KPROBES #define KPROBE_BLACKLIST () . = ALIGN(8); \ VMLINUX_SYMBOL(__start_kprobe_blacklist) = .; \ - *(_kprobe_blacklist) \ + KEEP(*(_kprobe_blacklist)) \ VMLINUX_SYMBOL(__stop_kprobe_blacklist) = .;#else #define KPROBE_BLACKLIST ()
@@ -123,10 +123,10 @@#ifdef CONFIG_EVENT_TRACING #define FTRACE_EVENTS () . = ALIGN(8); \ VMLINUX_SYMBOL(__start_ftrace_events) = .; \ - *(_ftrace_events) \ + KEEP(*(_ftrace_events)) \ VMLINUX_SYMBOL(__stop_ftrace_events) = .; \ VMLINUX_SYMBOL(__start_ftrace_enum_maps) = .; \ - *(_ftrace_enum_map) \ + KEEP(*(_ftrace_enum_map)) \ VMLINUX_SYMBOL(__stop_ftrace_enum_maps) = .;#else #define FTRACE_EVENTS ()
@@ -134,10 +134,10 @@#ifdef CONFIG_TRACING #define TRACE_PRINTKS () VMLINUX_SYMBOL(__start___trace_bprintk_fmt) = .; \ - *(__trace_printk_fmt)/* Trace_printk fmt' pointer */ \ + KEEP(*(__trace_printk_fmt))/* Trace_printk fmt' pointer */ \ VMLINUX_SYMBOL(__stop___trace_bprintk_fmt) = .;#define TRACEPOINT_STR () VMLINUX_SYMBOL(__start___tracepoint_str) = .; \ - *(__tracepoint_str)/* Trace_printk fmt' pointer */ \ + KEEP(*(__tracepoint_str))/* Trace_printk fmt' pointer */ \ VMLINUX_SYMBOL(__stop___tracepoint_str) = .;#else #define TRACE_PRINTKS ()
@@ -147,7 +147,7 @@#ifdef CONFIG_FTRACE_SYSCALLS #define TRACE_SYSCALLS () . = ALIGN(8); \ VMLINUX_SYMBOL(__start_syscalls_metadata) = .; \ - *(__syscalls_metadata) \ + KEEP(*(__syscalls_metadata)) \ VMLINUX_SYMBOL(__stop_syscalls_metadata) = .;#else #define TRACE_SYSCALLS ()
@@ -156,7 +156,7 @@#ifdef CONFIG_SERIAL_EARLYCON #define EARLYCON_TABLE () STRUCT_ALIGN(); \ VMLINUX_SYMBOL(__earlycon_table) = .; \ - *(__earlycon_table) \ + KEEP(*(__earlycon_table)) \ VMLINUX_SYMBOL(__earlycon_table_end) = .;#else #define EARLYCON_TABLE ()
@@ -169,8 +169,8 @@#define _OF_TABLE_1 (name) \ . = ALIGN(8); \ VMLINUX_SYMBOL(__##name##_of_table) = .; \ - *(__##name##_of_table) \ - *(__##name##_of_table_end) + KEEP(*(__##name##_of_table)) \ + KEEP(*(__##name##_of_table_end))#define CLKSRC_OF_TABLES () OF_TABLE(CONFIG_CLKSRC_OF, clksrc)#define IRQCHIP_OF_MATCH_TABLE () OF_TABLE(CONFIG_IRQCHIP, irqchip)
@@ -184,7 +184,7 @@#define ACPI_PROBE_TABLE (name) \ . = ALIGN(8); \ VMLINUX_SYMBOL(__##name##_acpi_probe_table) = .; \ - *(__##name##_acpi_probe_table) \ + KEEP(*(__##name##_acpi_probe_table)) \ VMLINUX_SYMBOL(__##name##_acpi_probe_table_end) = .;#else #define ACPI_PROBE_TABLE (name)
@@ -193,7 +193,7 @@#define KERNEL_DTB () \ STRUCT_ALIGN(); \ VMLINUX_SYMBOL(__dtb_start) = .; \ - *(.dtb.init.rodata) \ + KEEP(*(.dtb.init.rodata)) \ VMLINUX_SYMBOL(__dtb_end) = .;/*
@@ -214,11 +214,11 @@/* implement dynamic printk debug */ \ . = ALIGN(8); \ VMLINUX_SYMBOL(__start___jump_table) = .; \ - *(__jump_table ) \ + KEEP(*(__jump_table)) \ VMLINUX_SYMBOL(__stop___jump_table) = .; \ . = ALIGN(8); \ VMLINUX_SYMBOL(__start___verbose) = .; \ - *(__verbose ) \ + KEEP(*(__verbose)) \ VMLINUX_SYMBOL(__stop___verbose) = .; \ LIKELY_PROFILE() \BRANCH_PROFILE () \
@@ -271,10 +271,10 @@ VMLINUX_SYMBOL(__start_rodata) = .; \ *(.rodata) *(.rodata.*) \ RO_AFTER_INIT_DATA /* Read only after init */ \ - *(__vermagic) /* Kernel version magic */ \ +KEEP (*(__vermagic))/* Kernel version magic */ \ . = ALIGN(8); \ VMLINUX_SYMBOL(__start___tracepoints_ptrs) = .; \ - *(__tracepoints_ptrs) /* Tracepoints: pointer array */\ + KEEP(*(__tracepoints_ptrs)) /* Tracepoints: pointer array */ \ VMLINUX_SYMBOL(__stop___tracepoints_ptrs) = .; \ *(__tracepoints_strings)/* Tracepoints: strings */ \ } \
@@ -288,35 +288,35 @@/* PCI quirks */ \ .pci_fixup : AT(ADDR(.pci_fixup) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start_pci_fixups_early) = .; \ - *(.pci_fixup_early) \ + KEEP(*(.pci_fixup_early)) \ VMLINUX_SYMBOL(__end_pci_fixups_early) = .; \ VMLINUX_SYMBOL(__start_pci_fixups_header) = .; \ - *(.pci_fixup_header) \ + KEEP(*(.pci_fixup_header)) \ VMLINUX_SYMBOL(__end_pci_fixups_header) = .; \ VMLINUX_SYMBOL(__start_pci_fixups_final) = .; \ - *(.pci_fixup_final) \ + KEEP(*(.pci_fixup_final)) \ VMLINUX_SYMBOL(__end_pci_fixups_final) = .; \ VMLINUX_SYMBOL(__start_pci_fixups_enable) = .; \ - *(.pci_fixup_enable) \ + KEEP(*(.pci_fixup_enable)) \ VMLINUX_SYMBOL(__end_pci_fixups_enable) = .; \ VMLINUX_SYMBOL(__start_pci_fixups_resume) = .; \ - *(.pci_fixup_resume) \ + KEEP(*(.pci_fixup_resume)) \ VMLINUX_SYMBOL(__end_pci_fixups_resume) = .; \ VMLINUX_SYMBOL(__start_pci_fixups_resume_early) = .; \ - *(.pci_fixup_resume_early) \ + KEEP(*(.pci_fixup_resume_early)) \ VMLINUX_SYMBOL(__end_pci_fixups_resume_early) = .; \ VMLINUX_SYMBOL(__start_pci_fixups_suspend) = .; \ - *(.pci_fixup_suspend) \ + KEEP(*(.pci_fixup_suspend)) \ VMLINUX_SYMBOL(__end_pci_fixups_suspend) = .; \ VMLINUX_SYMBOL(__start_pci_fixups_suspend_late) = .; \ - *(.pci_fixup_suspend_late) \ + KEEP(*(.pci_fixup_suspend_late)) \ VMLINUX_SYMBOL(__end_pci_fixups_suspend_late) = .; \ } \ \/* Built-in firmware blobs */ \ .builtin_fw : AT(ADDR(.builtin_fw) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start_builtin_fw) = .; \ - *(.builtin_fw) \ + KEEP(*(.builtin_fw)) \ VMLINUX_SYMBOL(__end_builtin_fw) = .; \ } \ \
@@ -394,7 +394,7 @@ \/* Kernel symbol table: strings */ \ __ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) { \ - KEEP(*(__ksymtab_strings)) \ + *(__ksymtab_strings) \ } \ \/* __*init sections */ \
@@ -407,14 +407,14 @@/* Built-in module parameters. */ \ __param : AT(ADDR(__param) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start___param) = .; \ - *(__param ) \ + KEEP(*(__param)) \ VMLINUX_SYMBOL(__stop___param) = .; \ } \ \/* Built-in module versions. */ \ __modver : AT(ADDR(__modver) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start___modver) = .; \ - *(__modver ) \ + KEEP(*(__modver)) \ VMLINUX_SYMBOL(__stop___modver) = .; \ . = ALIGN((align)); \ VMLINUX_SYMBOL(__end_rodata) = .; \
@@ -517,7 +517,7 @@ . = ALIGN(align); \ __ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start___ex_table) = .; \ - *(__ex_table ) \ + KEEP(*(__ex_table)) \ VMLINUX_SYMBOL(__stop___ex_table) = .; \ }
@@ -533,9 +533,9 @@#ifdef CONFIG_CONSTRUCTORS #define KERNEL_CTORS () . = ALIGN(8); \ VMLINUX_SYMBOL(__ctors_start) = .; \ - *(.ctors) \ - *(SORT(.init_array.*)) \ - *(.init_array) \ + KEEP(*(.ctors)) \ + KEEP(*(SORT(.init_array.*))) \ + KEEP(*(.init_array)) \ VMLINUX_SYMBOL(__ctors_end) = .;#else #define KERNEL_CTORS ()
@@ -659,7 +659,7 @@ . = ALIGN(8); \ __bug_table : AT(ADDR(__bug_table) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start___bug_table) = .; \ - *(__bug_table ) \ + KEEP(*(__bug_table)) \ VMLINUX_SYMBOL(__stop___bug_table) = .; \ }#else
@@ -671,7 +671,7 @@ . = ALIGN(4); \ .tracedata : AT(ADDR(.tracedata) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__tracedata_start) = .; \ - *(.tracedata) \ + KEEP(*(.tracedata)) \ VMLINUX_SYMBOL(__tracedata_end) = .; \ } #else
@@ -688,7 +688,7 @@#define INIT_SETUP (initsetup_align) \ . = ALIGN(initsetup_align); \ VMLINUX_SYMBOL(__setup_start) = .; \ - *(.init.setup) \ + KEEP(*(.init.setup)) \ VMLINUX_SYMBOL(__setup_end) = .;#define INIT_CALLS_LEVEL (level) \
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2.9.3