* [PATCH 1/2] section garbage collection for i386
@ 2007-09-12 20:24 Denys Vlasenko
2007-09-12 20:30 ` [PATCH 2/2] " Denys Vlasenko
0 siblings, 1 reply; 3+ messages in thread
From: Denys Vlasenko @ 2007-09-12 20:24 UTC (permalink / raw)
To: Sam Ravnborg; +Cc: linux-kernel
[-- Attachment #1: Type: text/plain, Size: 325 bytes --]
Hi Sam,
This patch is preparatory: it adds a few KEEP() directives where
I forgot them in previous patch set, adds comments which explains
places where KEEP() is definitely not needed, and fixes i386 vdso generation
in an "obviously safe" way.
Please apply.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
--
vda
[-- Attachment #2: linux-2.6.23-rc4.5.fixes.patch --]
[-- Type: text/x-diff, Size: 2329 bytes --]
diff -urpN linux-2.6.23-rc4.gc4/arch/i386/kernel/vsyscall.lds.S linux-2.6.23-rc4.gc5/arch/i386/kernel/vsyscall.lds.S
--- linux-2.6.23-rc4.gc4/arch/i386/kernel/vsyscall.lds.S 2007-07-09 00:32:17.000000000 +0100
+++ linux-2.6.23-rc4.gc5/arch/i386/kernel/vsyscall.lds.S 2007-09-12 19:47:17.000000000 +0100
@@ -23,10 +23,10 @@ SECTIONS
is insufficient, ld -shared will barf. Just increase it here. */
. = VDSO_PRELINK_asm + 0x400;
- .text : { *(.text) } :text =0x90909090
+ .text : { *(.text) *(.text.*) } :text =0x90909090
.note : { *(.note.*) } :text :note
.eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr
- .eh_frame : { KEEP (*(.eh_frame)) } :text
+ .eh_frame : { KEEP(*(.eh_frame)) } :text
.dynamic : { *(.dynamic) } :text :dynamic
.useless : {
*(.got.plt) *(.got)
diff -urpN linux-2.6.23-rc4.gc4/include/asm-generic/vmlinux.lds.h linux-2.6.23-rc4.gc5/include/asm-generic/vmlinux.lds.h
--- linux-2.6.23-rc4.gc4/include/asm-generic/vmlinux.lds.h 2007-09-12 19:46:32.000000000 +0100
+++ linux-2.6.23-rc4.gc5/include/asm-generic/vmlinux.lds.h 2007-09-12 19:47:17.000000000 +0100
@@ -169,6 +169,7 @@
#define SCHED_TEXT \
ALIGN_FUNCTION(); \
VMLINUX_SYMBOL(__sched_text_start) = .; \
+ /* No need to KEEP */ \
*(.sched.text) \
VMLINUX_SYMBOL(__sched_text_end) = .;
@@ -177,12 +178,14 @@
#define LOCK_TEXT \
ALIGN_FUNCTION(); \
VMLINUX_SYMBOL(__lock_text_start) = .; \
+ /* No need to KEEP */ \
*(.spinlock.text) \
VMLINUX_SYMBOL(__lock_text_end) = .;
#define KPROBES_TEXT \
ALIGN_FUNCTION(); \
VMLINUX_SYMBOL(__kprobes_text_start) = .; \
+ /* No need to KEEP */ \
*(.kprobes.text) \
VMLINUX_SYMBOL(__kprobes_text_end) = .;
@@ -228,14 +231,16 @@
. = ALIGN(8); \
__bug_table : AT(ADDR(__bug_table) - LOAD_OFFSET) { \
__start___bug_table = .; \
- *(__bug_table) \
+ /* Support for BUG() */ \
+ KEEP(*(__bug_table)) \
__stop___bug_table = .; \
}
#define NOTES \
.notes : AT(ADDR(.notes) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start_notes) = .; \
- *(.note.*) \
+ /* For /sys/kernel/notes */ \
+ KEEP(*(.note.*)) \
VMLINUX_SYMBOL(__stop_notes) = .; \
}
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH 2/2] section garbage collection for i386
2007-09-12 20:24 [PATCH 1/2] section garbage collection for i386 Denys Vlasenko
@ 2007-09-12 20:30 ` Denys Vlasenko
2007-09-12 20:45 ` [PATCH 3/2] section garbage collection for i386 - BONUS TRACK Denys Vlasenko
0 siblings, 1 reply; 3+ messages in thread
From: Denys Vlasenko @ 2007-09-12 20:30 UTC (permalink / raw)
To: Sam Ravnborg; +Cc: linux-kernel
[-- Attachment #1: Type: text/plain, Size: 1658 bytes --]
Hi Sam,
This patch adds module linker script (completely analogous to x86_64),
and "minimally" fixes vmlinux linker script by adding KEEPs.
It also deleted an outdated comment and amends help text.
I got a few "section mismatch" warnings with .config which doesn't
show them (IIRC) on original kernel.
I took a look and I think that original kernel was actually in error
and these warnings are correct!
WARNING: vmlinux.o(.text.kmem_cache_create+0x32f): Section mismatch: reference to .init.refok.text:setup_cpu_cache (after 'kmem_cache_create')
WARNING: vmlinux.o(.text.vgacon_startup+0x2dd): Section mismatch: reference to .init.refok.text:vgacon_scrollback_startup (after 'vgacon_startup')
WARNING: vmlinux.o(.data.smp_ops+0x0): Section mismatch: reference to .init.text:native_smp_prepare_boot_cpu (after 'smp_ops')
WARNING: vmlinux.o(.data.smp_ops+0x4): Section mismatch: reference to .init.text:native_smp_prepare_cpus (after 'smp_ops')
WARNING: vmlinux.o(.data.smp_ops+0xc): Section mismatch: reference to .init.text:native_smp_cpus_done (after 'smp_ops')
WARNING: vmlinux.o(.data.vesafb_driver+0x0): Section mismatch: reference to .init.text:vesafb_probe (after 'vesafb_driver')
WARNING: vmlinux.o(.data.serial8250_console+0x20): Section mismatch: reference to .init.text:serial8250_console_setup (after 'serial8250_console')
WARNING: vmlinux.o(.data.dgrs_pci_driver+0x10): Section mismatch: reference to .init.text:dgrs_pci_probe (after 'dgrs_pci_driver')
Risk of this patch is analogous to last patch of first series -
run-tested and looks safe, but needs to go into -mm first.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
--
vda
[-- Attachment #2: linux-2.6.23-rc4.6.i386.patch --]
[-- Type: text/x-diff, Size: 9551 bytes --]
diff -urpN linux-2.6.23-rc4.gc5/arch/i386/kernel/modules.lds linux-2.6.23-rc4.gc6/arch/i386/kernel/modules.lds
--- linux-2.6.23-rc4.gc5/arch/i386/kernel/modules.lds 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.23-rc4.gc6/arch/i386/kernel/modules.lds 2007-09-12 19:49:10.000000000 +0100
@@ -0,0 +1,123 @@
+OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")
+OUTPUT_ARCH(i386)
+
+/*
+This linker script is used if CONFIG_DISCARD_UNUSED_SECTIONS=y.
+We are trying to minimize number of sections in .ko file
+by coalescing .text.x, rodata.x, .data.x and bss.x input
+sections into one output section.
+
+This script may be usable without CONFIG_DISCARD_UNUSED_SECTIONS too.
+
+Kernel module loader (kernel/module.c) needs to see the following sections:
+
+.init*
+.exit*
+.gnu.linkonce.this_module
+.percpu.data
+.modinfo
+__ksymtab_gpl_future
+__ksymtab_gpl
+__ksymtab_unused_gpl
+__ksymtab_unused
+__ksymtab
+__kcrctab_gpl_future
+__kcrctab_gpl
+__kcrctab_unused_gpl
+__kcrctab_unused
+__kcrctab
+__param
+__ex_table
+__obsparm
+__versions
+.debug (?!)
+$ARCH_UNWIND_SECTION_NAME
+
+They must not be coalesced into sections with other names.
+
+*/
+
+SECTIONS
+{
+ /* ro, code */
+
+ /* .fixup and .altinstr_replacement work just fine
+ * without dedicated sections */
+ .text : {
+ *(SORT_BY_ALIGNMENT(.text*))
+ /* __ex_table points here */
+ *(SORT_BY_ALIGNMENT(.fixup*))
+ /* .altinstructions points here */
+ *(SORT_BY_ALIGNMENT(.altinstr_replacement*))
+ }
+ /* only if CONFIG_MODULE_UNLOAD */
+ .exit.text : { *(SORT_BY_ALIGNMENT(.exit.text)) }
+ /* end CONFIG_MODULE_UNLOAD */
+
+ /* ro, data */
+
+ .rodata : { *(SORT_BY_ALIGNMENT(.rodata*)) }
+ /* Kernel searches through this table when it needs to handle an exception */
+ __ex_table : { *(__ex_table*) }
+ /* These two tables are not currently handled by in-kernel module loader,
+ * but likely will be in future kernels */
+ .altinstructions : { *(.altinstructions*) }
+ .smp_locks : { *(.smp_locks*) }
+ /* Used by depmod in order to generate modules.dep, modules.symbols */
+ __ksymtab_strings : { *(SORT_BY_ALIGNMENT(__ksymtab_strings)) }
+ /* EXPORT_SYMBOLs exported in this module */
+ __ksymtab_gpl_future : { *(__ksymtab_gpl_future) }
+ __ksymtab_gpl : { *(__ksymtab_gpl) }
+ __ksymtab_unused_gpl : { *(__ksymtab_unused_gpl) }
+ __ksymtab_unused : { *(__ksymtab_unused) }
+ __ksymtab : { *(__ksymtab) }
+ /* only if CONFIG_MODVERSIONS */
+ __kcrctab_gpl_future : { *(__kcrctab_gpl_future) }
+ __kcrctab_gpl : { *(__kcrctab_gpl) }
+ __kcrctab_unused_gpl : { *(__kcrctab_unused_gpl) }
+ __kcrctab_unused : { *(__kcrctab_unused) }
+ __kcrctab : { *(__kcrctab) }
+ /* from *.mod.c: const struct modversion_info ____versions[] */
+ __versions : { *(__versions) }
+ /* end CONFIG_MODVERSIONS */
+ __param : { *(.__param) }
+ __obsparm : { *(.__obsparm) }
+ /* from *.mod.c: const char __module_depends[] "depends=mod1,mod2" */
+ .modinfo : { *(SORT_BY_ALIGNMENT(.modinfo)) }
+ /* ld segfaults if we give it --build-id and then discard this section */
+ .note.gnu.build-id : { *(.note.gnu.build-id) }
+
+ /* rw, data */
+
+ .data : {
+ *(SORT_BY_ALIGNMENT(.cacheline_aligned.data))
+ *(SORT_BY_ALIGNMENT(.data*))
+ *(SORT_BY_ALIGNMENT(.read_mostly.data))
+ }
+ /* from *.mod.c: struct module __this_module */
+ .gnu.linkonce.this_module : { *(.gnu.linkonce.this_module) }
+ /* only if CONFIG_SMP */
+ .percpu.data : { *(SORT_BY_ALIGNMENT(.percpu.data)) }
+ /* end CONFIG_SMP */
+ /* only if CONFIG_MODULE_UNLOAD */
+ .exit.data : { *(SORT_BY_ALIGNMENT(.exit.data)) }
+ /* end CONFIG_MODULE_UNLOAD */
+
+ /* rw, data initialized to 0 */
+
+ .bss : { *(SORT_BY_ALIGNMENT(.bss*)) }
+
+ /* init code/data. discarded at the end of sys_init_module() */
+
+ .init.text : { *(SORT_BY_ALIGNMENT(.init.text)) }
+ .init.data : { *(SORT_BY_ALIGNMENT(.init.data)) }
+
+ /* Be bold and resist the temptation to pull junk "by default" */
+
+ /DISCARD/ : { *(*) }
+
+ /* If you are going to revive these, please add comment why it is needed */
+ /* .debug : { *(.debug) } */
+ /* .comment : { *(.comment) } */
+ /* .note.GNU-stack : { *(.note.GNU-stack) } */
+}
diff -urpN linux-2.6.23-rc4.gc5/arch/i386/kernel/vmlinux.lds.S linux-2.6.23-rc4.gc6/arch/i386/kernel/vmlinux.lds.S
--- linux-2.6.23-rc4.gc5/arch/i386/kernel/vmlinux.lds.S 2007-09-12 19:46:32.000000000 +0100
+++ linux-2.6.23-rc4.gc6/arch/i386/kernel/vmlinux.lds.S 2007-09-12 19:51:42.000000000 +0100
@@ -32,7 +32,7 @@ SECTIONS
.head.text : AT(ADDR(.head.text) - LOAD_OFFSET) {
_text = .; /* Text and read-only data */
- *(.head.text)
+ KEEP(*(.head.text))
} :text = 0x9090
/* read-only */
@@ -41,6 +41,7 @@ SECTIONS
SCHED_TEXT
LOCK_TEXT
KPROBES_TEXT
+ /* No need to KEEP - referenced by __ex_table */
*(.fixup)
*(.gnu.warning)
_etext = .; /* End of text section */
@@ -49,7 +50,7 @@ SECTIONS
. = ALIGN(16); /* Exception table */
__ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) {
__start___ex_table = .;
- *(__ex_table)
+ KEEP(*(__ex_table))
__stop___ex_table = .;
}
@@ -60,7 +61,8 @@ SECTIONS
. = ALIGN(4);
.tracedata : AT(ADDR(.tracedata) - LOAD_OFFSET) {
__tracedata_start = .;
- *(.tracedata)
+ /* Resume debug tracing */
+ KEEP(*(.tracedata))
__tracedata_end = .;
}
@@ -71,11 +73,12 @@ SECTIONS
.data : AT(ADDR(.data) - LOAD_OFFSET) { /* Data */
DATA_DATA
CONSTRUCTORS
- } :data
+ } :data
. = ALIGN(4096);
.data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
__nosave_begin = .;
+ /* No need to KEEP */
*(.nosave.data)
. = ALIGN(4096);
__nosave_end = .;
@@ -108,19 +111,13 @@ SECTIONS
. = ALIGN(4096);
.smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) {
__smp_locks = .;
- *(.smp_locks)
+ KEEP(*(.smp_locks))
__smp_locks_end = .;
}
- /* will be freed after init
- * Following ALIGN() is required to make sure no other data falls on the
- * same page where __smp_alt_end is pointing as that page might be freed
- * after boot. Always make sure that ALIGN() directive is present after
- * the section which contains __smp_alt_end.
- */
- . = ALIGN(4096);
- /* will be freed after init */
- . = ALIGN(4096); /* Init code and data */
+ /* Will be freed after init */
+ /* Init code and data */
+ . = ALIGN(4096);
.init.text : AT(ADDR(.init.text) - LOAD_OFFSET) {
__init_begin = .;
_sinittext = .;
@@ -131,7 +128,9 @@ SECTIONS
. = ALIGN(16);
.init.setup : AT(ADDR(.init.setup) - LOAD_OFFSET) {
__setup_start = .;
- *(.init.setup)
+ /* __setup_param() macro produces these,
+ * obsolete_checksetup() processes them */
+ KEEP(*(.init.setup))
__setup_end = .;
}
.initcall.init : AT(ADDR(.initcall.init) - LOAD_OFFSET) {
@@ -141,46 +140,50 @@ SECTIONS
}
.con_initcall.init : AT(ADDR(.con_initcall.init) - LOAD_OFFSET) {
__con_initcall_start = .;
- *(.con_initcall.init)
+ KEEP(*(.con_initcall.init))
__con_initcall_end = .;
}
SECURITY_INIT
. = ALIGN(4);
.altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {
__alt_instructions = .;
- *(.altinstructions)
+ KEEP(*(.altinstructions))
__alt_instructions_end = .;
}
.altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) {
+ /* No need to KEEP - referenced by .altinstructions */
*(.altinstr_replacement)
}
. = ALIGN(4);
.parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {
__parainstructions = .;
- *(.parainstructions)
+ KEEP(*(.parainstructions))
__parainstructions_end = .;
}
- /* .exit.text is discard at runtime, not link time, to deal with references
+ /* .exit.text is discarded at runtime, not link time, to deal with references
from .altinstructions and .eh_frame */
.exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) { *(.exit.text) }
.exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) { *(.exit.data) }
+
#if defined(CONFIG_BLK_DEV_INITRD)
. = ALIGN(4096);
.init.ramfs : AT(ADDR(.init.ramfs) - LOAD_OFFSET) {
__initramfs_start = .;
- *(.init.ramfs)
+ KEEP(*(.init.ramfs))
__initramfs_end = .;
}
#endif
+
. = ALIGN(4096);
- .percpu.data : AT(ADDR(.percpu.data) - LOAD_OFFSET) {
+ .percpu.data : AT(ADDR(.percpu.data) - LOAD_OFFSET) {
__per_cpu_start = .;
*(.percpu.data)
*(.percpu.shared_aligned.data)
__per_cpu_end = .;
}
. = ALIGN(4096);
- /* freed after init ends here */
+
+ /* End of "freed after init" portion */
.bss : AT(ADDR(.bss) - LOAD_OFFSET) {
__init_end = .;
@@ -189,7 +192,7 @@ SECTIONS
* we want to combine into bss, otherwise gcc does not set
* 'nobits' flag for the section, and it cannot be merged into bss. */
*(.bss.k.page_aligned)
- *(.bss)
+ *(SORT_BY_ALIGNMENT(.bss*))
. = ALIGN(4);
__bss_stop = .;
_end = . ;
@@ -201,7 +204,7 @@ SECTIONS
/* Sections to be discarded */
/DISCARD/ : {
*(.exitcall.exit)
- }
+ }
STABS_DEBUG
diff -urpN linux-2.6.23-rc4.gc5/init/Kconfig linux-2.6.23-rc4.gc6/init/Kconfig
--- linux-2.6.23-rc4.gc5/init/Kconfig 2007-09-12 19:46:32.000000000 +0100
+++ linux-2.6.23-rc4.gc6/init/Kconfig 2007-09-12 21:23:39.000000000 +0100
@@ -360,7 +360,7 @@ config DISCARD_UNUSED_SECTIONS
and even then surprises are likely.
This option also requires architecture-specific changes.
- Currently working architectures: x86_64
+ Currently working architectures: x86_64, i386
If unsure, say N.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH 3/2] section garbage collection for i386 - BONUS TRACK
2007-09-12 20:30 ` [PATCH 2/2] " Denys Vlasenko
@ 2007-09-12 20:45 ` Denys Vlasenko
0 siblings, 0 replies; 3+ messages in thread
From: Denys Vlasenko @ 2007-09-12 20:45 UTC (permalink / raw)
To: Sam Ravnborg; +Cc: linux-kernel
[-- Attachment #1: Type: text/plain, Size: 8595 bytes --]
Hi Sam,
This patch makes i386 vmlinux linker script simpler
by minimizing number of generated sections.
For example, these sections:
21 .init.text 000204a0 78701000 00701000 00502000 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
22 .init.data 000268db 787214a0 007214a0 005224a0 2**3
CONTENTS, ALLOC, LOAD, DATA
23 .init.setup 00000654 78747d80 00747d80 00548d80 2**2
CONTENTS, ALLOC, LOAD, DATA
24 .initcall.init 000004c4 787483d4 007483d4 005493d4 2**2
CONTENTS, ALLOC, LOAD, DATA
25 .con_initcall.init 00000008 78748898 00748898 00549898 2**2
CONTENTS, ALLOC, LOAD, DATA
26 .altinstructions 00009c23 787488a0 007488a0 005498a0 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
27 .altinstr_replacement 000027de 787524c3 007524c3 005534c3 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
28 .exit.text 00000f31 78754ca4 00754ca4 00555ca4 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
29 .init.ramfs 00000086 78756000 00756000 00557000 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA
code, data, data, data, rodata, code, code, data... -
doesn't look clean.
Can more sanely be grouped like this:
15 .init.text 00023baf 78701000 00701000 00502000 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
16 .init.rodata 00009ca8 78725000 00725000 00526000 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
17 .init.data 00027408 7872eca8 0072eca8 0052fca8 2**3
CONTENTS, ALLOC, LOAD, DATA
All in all, we have 20 sections instead of 32, and it still boots okay.
Full listing:
Before:
$ objdump -h
linux-2.6.23-rc4.gc6.t/vmlinux: file format elf32-i386
Sections:
Idx Name Size VMA LMA File off Algn
0 .head.text 00000379 78200000 00200000 00001000 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
1 .text 003646da 78200380 00200380 00001380 2**4
CONTENTS, ALLOC, LOAD, READONLY, CODE
2 __ex_table 00000ee8 78564a60 00564a60 00365a60 2**3
CONTENTS, ALLOC, LOAD, READONLY, DATA
3 .notes 00000024 78565948 00565948 00366948 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
4 .rodata 000e85fe 78566000 00566000 00367000 2**3
CONTENTS, ALLOC, LOAD, READONLY, DATA
5 .pci_fixup 00000700 7864e600 0064e600 0044f600 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
6 __ksymtab 000057a0 7864ed00 0064ed00 0044fd00 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
7 __ksymtab_gpl 00001ac0 786544a0 006544a0 004554a0 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
8 __ksymtab_gpl_future 00000018 78655f60 00655f60 00456f60 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
9 __kcrctab 00002bd0 78655f78 00655f78 00456f78 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
10 __kcrctab_gpl 00000d60 78658b48 00658b48 00459b48 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
11 __kcrctab_gpl_future 0000000c 786598a8 006598a8 0045a8a8 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
12 __ksymtab_strings 00010d8b 786598b4 006598b4 0045a8b4 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
13 __param 00001838 7866a640 0066a640 0046b640 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
14 .data 0007fe99 7866c000 0066c000 0046d000 2**7
CONTENTS, ALLOC, LOAD, DATA
15 .data_nosave 00001000 786ec000 006ec000 004ed000 2**12
CONTENTS, ALLOC, LOAD, DATA
16 .page_aligned.data 00000800 786ed000 006ed000 004ee000 2**2
CONTENTS, ALLOC, LOAD, DATA
17 .cacheline_aligned.data 0000a000 786ed800 006ed800 004ee800 2**7
CONTENTS, ALLOC, LOAD, DATA
18 .read_mostly.data 000020d0 786f7800 006f7800 004f8800 2**7
CONTENTS, ALLOC, LOAD, DATA
19 .init_task.data 00002000 786fa000 006fa000 004fb000 2**2
CONTENTS, ALLOC, LOAD, DATA
20 .smp_locks 00004798 786fc000 006fc000 004fd000 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
21 .init.text 000204a0 78701000 00701000 00502000 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
22 .init.data 000268db 787214a0 007214a0 005224a0 2**3
CONTENTS, ALLOC, LOAD, DATA
23 .init.setup 00000654 78747d80 00747d80 00548d80 2**2
CONTENTS, ALLOC, LOAD, DATA
24 .initcall.init 000004c4 787483d4 007483d4 005493d4 2**2
CONTENTS, ALLOC, LOAD, DATA
25 .con_initcall.init 00000008 78748898 00748898 00549898 2**2
CONTENTS, ALLOC, LOAD, DATA
26 .altinstructions 00009c23 787488a0 007488a0 005498a0 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
27 .altinstr_replacement 000027de 787524c3 007524c3 005534c3 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
28 .exit.text 00000f31 78754ca4 00754ca4 00555ca4 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
29 .init.ramfs 00000086 78756000 00756000 00557000 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA
30 .percpu.data 00005f38 78757000 00757000 00558000 2**12
CONTENTS, ALLOC, LOAD, DATA
31 .bss 00047000 7875d000 0075d000 0055df38 2**12
ALLOC
32 .comment 00005004 00000000 00000000 0055df38 2**0
CONTENTS, READONLY
After:
linux-2.6.23-rc4.gc7.t/vmlinux: file format elf32-i386
Sections:
Idx Name Size VMA LMA File off Algn
0 .text 00364a5a 78200000 00200000 00001000 2**4
CONTENTS, ALLOC, LOAD, READONLY, CODE
1 __ex_table 00000ee8 78564a60 00564a60 00365a60 2**3
CONTENTS, ALLOC, LOAD, READONLY, DATA
2 .notes 00000024 78565948 00565948 00366948 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
3 .rodata 000e8602 78566000 00566000 00367000 2**3
CONTENTS, ALLOC, LOAD, READONLY, DATA
4 .pci_fixup 00000700 7864e604 0064e604 0044f604 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
5 __ksymtab 000057a0 7864ed04 0064ed04 0044fd04 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
6 __ksymtab_gpl 00001ac0 786544a4 006544a4 004554a4 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
7 __ksymtab_gpl_future 00000018 78655f64 00655f64 00456f64 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
8 __kcrctab 00002bd0 78655f7c 00655f7c 00456f7c 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
9 __kcrctab_gpl 00000d60 78658b4c 00658b4c 00459b4c 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
10 __kcrctab_gpl_future 0000000c 786598ac 006598ac 0045a8ac 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
11 __ksymtab_strings 00010d8b 786598b8 006598b8 0045a8b8 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
12 __param 00001838 7866a644 0066a644 0046b644 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
13 .data 0008f7d0 7866c000 0066c000 0046d000 2**12
CONTENTS, ALLOC, LOAD, DATA
14 .smp_locks 00004798 786fc000 006fc000 004fd000 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
15 .init.text 00023baf 78701000 00701000 00502000 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
16 .init.rodata 00009ca8 78725000 00725000 00526000 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
17 .init.data 00027408 7872eca8 0072eca8 0052fca8 2**3
CONTENTS, ALLOC, LOAD, DATA
18 .percpu.data 00005f38 78757000 00757000 00558000 2**12
CONTENTS, ALLOC, LOAD, DATA
19 .bss 00047000 7875d000 0075d000 0055df38 2**12
ALLOC
20 .comment 00005004 00000000 00000000 0055df38 2**0
CONTENTS, READONLY
Patch is run-tested.
It's purely cleanup work, it's not bringing any noticeable
size wins (well, maybe statistically it will have a bit less
alignment padding because I placed together a few page-aligned
chunks, but that's all).
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
--
vda
[-- Attachment #2: linux-2.6.23-rc4.7.i386part2.patch --]
[-- Type: text/x-diff, Size: 6591 bytes --]
diff -urpN linux-2.6.23-rc4.gc6/arch/i386/kernel/vmlinux.lds.S linux-2.6.23-rc4.gc7/arch/i386/kernel/vmlinux.lds.S
--- linux-2.6.23-rc4.gc6/arch/i386/kernel/vmlinux.lds.S 2007-09-12 19:51:42.000000000 +0100
+++ linux-2.6.23-rc4.gc7/arch/i386/kernel/vmlinux.lds.S 2007-09-12 21:10:38.000000000 +0100
@@ -6,7 +6,19 @@
* at run time. Absolute symbols are not relocated. If symbol value should
* change if kernel is relocated, make the symbol section relative
* by putting it inside the section definition.
+ *
+ * Try to avoid creating output sections needlessly.
+ * Group pieces with same attributes (ro/rw, code/data,
+ * persistent/discarded-after-init) together in one section.
+ *
+ * Statistically, padding is smaller if input sections
+ * within output section are sorted by alignment in descending order.
+ *
+ * If you need to ALIGN a section, putting ALIGN immediately before section
+ * can result in smaller on-disk image than when you put it immeadiately
+ * after section's opening '{'.
*/
+
#define LOAD_OFFSET __PAGE_OFFSET
#include <asm-generic/vmlinux.lds.h>
@@ -18,6 +30,7 @@
OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")
OUTPUT_ARCH(i386)
ENTRY(phys_startup_32)
+
jiffies = jiffies_64;
PHDRS {
@@ -30,13 +43,11 @@ SECTIONS
. = LOAD_OFFSET + LOAD_PHYSICAL_ADDR;
phys_startup_32 = startup_32 - LOAD_OFFSET;
- .head.text : AT(ADDR(.head.text) - LOAD_OFFSET) {
- _text = .; /* Text and read-only data */
- KEEP(*(.head.text))
- } :text = 0x9090
-
/* read-only */
.text : AT(ADDR(.text) - LOAD_OFFSET) {
+ _text = .; /* Text and read-only data */
+ KEEP(*(.head.text))
+
TEXT_TEXT
SCHED_TEXT
LOCK_TEXT
@@ -54,6 +65,7 @@ SECTIONS
__stop___ex_table = .;
}
+ /* Hm? NOTES end up marked as CODE in vmlinux, but they are not. FIXME */
NOTES :text :note
BUG_TABLE :text
@@ -69,45 +81,39 @@ SECTIONS
RODATA
/* writeable */
- . = ALIGN(4096);
+ . = ALIGN(THREAD_SIZE); /* at least 4k */
.data : AT(ADDR(.data) - LOAD_OFFSET) { /* Data */
- DATA_DATA
- CONSTRUCTORS
- } :data
+ /* init_task */
+ *(.init_task.data)
- . = ALIGN(4096);
- .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
+ . = ALIGN(4096);
+ *(.page_aligned.data)
+
+ . = ALIGN(4096);
__nosave_begin = .;
/* No need to KEEP */
*(.nosave.data)
. = ALIGN(4096);
__nosave_end = .;
- }
- . = ALIGN(4096);
- .page_aligned.data : AT(ADDR(.page_aligned.data) - LOAD_OFFSET) {
- *(.page_aligned.data)
+ /* The IDT has to be page-aligned because of F0 0F bug */
*(.idt.data)
- }
- . = ALIGN(32);
- .cacheline_aligned.data : AT(ADDR(.cacheline_aligned.data) - LOAD_OFFSET) {
+ DATA_DATA
+ CONSTRUCTORS
+
+ . = ALIGN(32);
*(.cacheline_aligned.data)
- }
- /* rarely changed data like cpu maps */
- . = ALIGN(32);
- .read_mostly.data : AT(ADDR(.read_mostly.data) - LOAD_OFFSET) {
+ /* rarely changed data like cpu maps */
+ . = ALIGN(32);
*(.read_mostly.data)
- _edata = .; /* End of data section */
- }
- . = ALIGN(THREAD_SIZE); /* init_task */
- .init_task.data : AT(ADDR(.init_task.data) - LOAD_OFFSET) {
- *(.init_task.data)
- }
+ _edata = .;
+ } :data
+
+ /* Might get freed after init */
- /* might get freed after init */
. = ALIGN(4096);
.smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) {
__smp_locks = .;
@@ -116,75 +122,80 @@ SECTIONS
}
/* Will be freed after init */
- /* Init code and data */
+
. = ALIGN(4096);
.init.text : AT(ADDR(.init.text) - LOAD_OFFSET) {
__init_begin = .;
_sinittext = .;
*(.init.text)
_einittext = .;
+
+ /* No need to KEEP - referenced by .altinstructions */
+ *(.altinstr_replacement)
+
+ /* .exit.text is discarded at runtime, not link time, to deal with references
+ from .altinstructions and .eh_frame */
+ *(.exit.text)
+ }
+
+ /* ro, code */
+ SECURITY_INIT
+
+#if defined(CONFIG_BLK_DEV_INITRD)
+ /* ALIGN outside section may make on-disk image smaller */
+ . = ALIGN(4096);
+#endif
+ .init.rodata : AT(ADDR(.init.rodata) - LOAD_OFFSET) {
+#if defined(CONFIG_BLK_DEV_INITRD)
+ __initramfs_start = .;
+ KEEP(*(.init.ramfs))
+ __initramfs_end = .;
+#endif
+ . = ALIGN(4);
+ __alt_instructions = .;
+ KEEP(*(.altinstructions))
+ __alt_instructions_end = .;
+
+ . = ALIGN(4);
+ __parainstructions = .;
+ KEEP(*(.parainstructions))
+ __parainstructions_end = .;
}
- .init.data : AT(ADDR(.init.data) - LOAD_OFFSET) { *(.init.data) }
- . = ALIGN(16);
- .init.setup : AT(ADDR(.init.setup) - LOAD_OFFSET) {
+
+ .init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
+ *(.init.data)
+
+ . = ALIGN(16);
__setup_start = .;
/* __setup_param() macro produces these,
* obsolete_checksetup() processes them */
KEEP(*(.init.setup))
__setup_end = .;
- }
- .initcall.init : AT(ADDR(.initcall.init) - LOAD_OFFSET) {
+
__initcall_start = .;
INITCALLS
__initcall_end = .;
- }
- .con_initcall.init : AT(ADDR(.con_initcall.init) - LOAD_OFFSET) {
+
__con_initcall_start = .;
KEEP(*(.con_initcall.init))
__con_initcall_end = .;
- }
- SECURITY_INIT
- . = ALIGN(4);
- .altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {
- __alt_instructions = .;
- KEEP(*(.altinstructions))
- __alt_instructions_end = .;
- }
- .altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) {
- /* No need to KEEP - referenced by .altinstructions */
- *(.altinstr_replacement)
- }
- . = ALIGN(4);
- .parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {
- __parainstructions = .;
- KEEP(*(.parainstructions))
- __parainstructions_end = .;
- }
- /* .exit.text is discarded at runtime, not link time, to deal with references
- from .altinstructions and .eh_frame */
- .exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) { *(.exit.text) }
- .exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) { *(.exit.data) }
-#if defined(CONFIG_BLK_DEV_INITRD)
- . = ALIGN(4096);
- .init.ramfs : AT(ADDR(.init.ramfs) - LOAD_OFFSET) {
- __initramfs_start = .;
- KEEP(*(.init.ramfs))
- __initramfs_end = .;
+ /* TODO: can .exit.data be discarded at link time? */
+ *(.exit.data)
}
-#endif
. = ALIGN(4096);
.percpu.data : AT(ADDR(.percpu.data) - LOAD_OFFSET) {
__per_cpu_start = .;
- *(.percpu.data)
+ *(SORT_BY_ALIGNMENT(.percpu.data))
+ /* Dont move in front of .percpu.data, .percpu.data contains page-aligned stuff */
*(.percpu.shared_aligned.data)
__per_cpu_end = .;
}
- . = ALIGN(4096);
/* End of "freed after init" portion */
+ . = ALIGN(4096);
.bss : AT(ADDR(.bss) - LOAD_OFFSET) {
__init_end = .;
__bss_start = .; /* BSS */
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2007-09-12 20:46 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2007-09-12 20:24 [PATCH 1/2] section garbage collection for i386 Denys Vlasenko
2007-09-12 20:30 ` [PATCH 2/2] " Denys Vlasenko
2007-09-12 20:45 ` [PATCH 3/2] section garbage collection for i386 - BONUS TRACK Denys Vlasenko
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