hi again,
I'm trying to come up with some 'minimal demo' program for
__initcall() feature.
question is, to the ld, is there any way to specify
only these three lines
| __initcall_start = .;
| .initcall.init : { *(.initcall.init) }
| __initcall_end = .;
rather than taking the default script and then modifying it?
thank you,
kenji
::::::::::::::
a.c
::::::::::::::
/*
* initcall demo -- see include/linux/init.h
*
* gcc -Xlinker -T a.lds -o a a.c && ./a
*/
typedef int (*initcall_t)(void);
extern initcall_t __initcall_start, __initcall_end;
#define __initcall(fn) static initcall_t __initcall_##fn __init_call = fn
#define __init_call __attribute__ ((unused,__section__ (".initcall.init")))
static int f1(void)
{
printf("%s\n", __FUNCTION__);
}
__initcall(f1);
static int f2(void)
{
printf("%s\n", __FUNCTION__);
}
__initcall(f2);
main()
{
initcall_t *call;
printf("__initcall_start = %p\n", &__initcall_start);
printf("__initcall_end = %p\n", &__initcall_end);
call = &__initcall_start;
do {
printf("calling %p\n", call);
(*call)();
call++;
} while (call < &__initcall_end);
}
::::::::::::::
a.lds
::::::::::::::
/*
* this file was created based on binutils/ld/ldscripts/elf_i386.x
*
* the original was duplicated and then the following three lines
* were added:
*
* __initcall_start = .;
* .initcall.init : { *(.initcall.init) }
* __initcall_end = .;
*/
/* Default linker script, for normal executables */
OUTPUT_FORMAT("elf32-i386", "elf32-i386",
"elf32-i386")
OUTPUT_ARCH(i386)
ENTRY(_start)
SEARCH_DIR("/home/me/opt/binutils-current/i686-pc-linux-gnu/lib"); SEARCH_DIR("/home/me/opt/binutils-current/lib"); SEARCH_DIR("/usr/local/lib"); SEARCH_DIR("/lib"); SEARCH_DIR("/usr/lib");
/* Do we need any of these for elf?
__DYNAMIC = 0; */
SECTIONS
{
/* Read-only sections, merged into text segment: */
. = 0x08048000 + SIZEOF_HEADERS;
.interp : { *(.interp) }
.hash : { *(.hash) }
.dynsym : { *(.dynsym) }
.dynstr : { *(.dynstr) }
.gnu.version : { *(.gnu.version) }
.gnu.version_d : { *(.gnu.version_d) }
.gnu.version_r : { *(.gnu.version_r) }
.rel.init : { *(.rel.init) }
.rela.init : { *(.rela.init) }
.rel.text : { *(.rel.text .rel.text.* .rel.gnu.linkonce.t.*) }
.rela.text : { *(.rela.text .rela.text.* .rela.gnu.linkonce.t.*) }
.rel.fini : { *(.rel.fini) }
.rela.fini : { *(.rela.fini) }
.rel.rodata : { *(.rel.rodata .rel.rodata.* .rel.gnu.linkonce.r.*) }
.rela.rodata : { *(.rela.rodata .rela.rodata.* .rela.gnu.linkonce.r.*) }
.rel.data : { *(.rel.data .rel.data.* .rel.gnu.linkonce.d.*) }
.rela.data : { *(.rela.data .rela.data.* .rela.gnu.linkonce.d.*) }
.rel.tdata : { *(.rel.tdata .rel.tdata.* .rel.gnu.linkonce.td.*) }
.rela.tdata : { *(.rela.tdata .rela.tdata.* .rela.gnu.linkonce.td.*) }
.rel.tbss : { *(.rel.tbss .rel.tbss.* .rel.gnu.linkonce.tb.*) }
.rela.tbss : { *(.rela.tbss .rela.tbss.* .rela.gnu.linkonce.tb.*) }
.rel.ctors : { *(.rel.ctors) }
.rela.ctors : { *(.rela.ctors) }
.rel.dtors : { *(.rel.dtors) }
.rela.dtors : { *(.rela.dtors) }
.rel.got : { *(.rel.got) }
.rela.got : { *(.rela.got) }
.rel.bss : { *(.rel.bss .rel.bss.* .rel.gnu.linkonce.b.*) }
.rela.bss : { *(.rela.bss .rela.bss.* .rela.gnu.linkonce.b.*) }
.rel.plt : { *(.rel.plt) }
.rela.plt : { *(.rela.plt) }
.init :
{
KEEP (*(.init))
} =0x90909090
.plt : { *(.plt) }
.text :
{
*(.text .stub .text.* .gnu.linkonce.t.*)
/* .gnu.warning sections are handled specially by elf32.em. */
*(.gnu.warning)
} =0x90909090
__initcall_start = .;
.initcall.init : { *(.initcall.init) }
__initcall_end = .;
.fini :
{
KEEP (*(.fini))
} =0x90909090
PROVIDE (__etext = .);
PROVIDE (_etext = .);
PROVIDE (etext = .);
.rodata : { *(.rodata .rodata.* .gnu.linkonce.r.*) }
.rodata1 : { *(.rodata1) }
.eh_frame_hdr : { *(.eh_frame_hdr) }
/* Adjust the address for the data segment. We want to adjust up to
the same address within the page on the next page up. */
. = ALIGN (0x1000) - ((0x1000 - .) & (0x1000 - 1)); . = DATA_SEGMENT_ALIGN (0x1000, 0x1000);
/* Ensure the __preinit_array_start label is properly aligned. We
could instead move the label definition inside the section, but
the linker would then create the section even if it turns out to
be empty, which isn't pretty. */
. = ALIGN(32 / 8);
PROVIDE (__preinit_array_start = .);
.preinit_array : { *(.preinit_array) }
PROVIDE (__preinit_array_end = .);
PROVIDE (__init_array_start = .);
.init_array : { *(.init_array) }
PROVIDE (__init_array_end = .);
PROVIDE (__fini_array_start = .);
.fini_array : { *(.fini_array) }
PROVIDE (__fini_array_end = .);
.data :
{
*(.data .data.* .gnu.linkonce.d.*)
SORT(CONSTRUCTORS)
}
.data1 : { *(.data1) }
.tdata : { *(.tdata .tdata.* .gnu.linkonce.td.*) }
.tbss : { *(.tbss .tbss.* .gnu.linkonce.tb.*) *(.tcommon) }
.eh_frame : { KEEP (*(.eh_frame)) }
.gcc_except_table : { *(.gcc_except_table) }
.dynamic : { *(.dynamic) }
.ctors :
{
/* gcc uses crtbegin.o to find the start of
the constructors, so we make sure it is
first. Because this is a wildcard, it
doesn't matter if the user does not
actually link against crtbegin.o; the
linker won't look for a file to match a
wildcard. The wildcard also means that it
doesn't matter which directory crtbegin.o
is in. */
KEEP (*crtbegin*.o(.ctors))
/* We don't want to include the .ctor section from
from the crtend.o file until after the sorted ctors.
The .ctor section from the crtend file contains the
end of ctors marker and it must be last */
KEEP (*(EXCLUDE_FILE (*crtend*.o ) .ctors))
KEEP (*(SORT(.ctors.*)))
KEEP (*(.ctors))
}
.dtors :
{
KEEP (*crtbegin*.o(.dtors))
KEEP (*(EXCLUDE_FILE (*crtend*.o ) .dtors))
KEEP (*(SORT(.dtors.*)))
KEEP (*(.dtors))
}
.jcr : { KEEP (*(.jcr)) }
.got : { *(.got.plt) *(.got) }
_edata = .;
PROVIDE (edata = .);
__bss_start = .;
.bss :
{
*(.dynbss)
*(.bss .bss.* .gnu.linkonce.b.*)
*(COMMON)
/* Align here to ensure that the .bss section occupies space up to
_end. Align after .bss to ensure correct alignment even if the
.bss section disappears because there are no input sections. */
. = ALIGN(32 / 8);
}
. = ALIGN(32 / 8);
_end = .;
PROVIDE (end = .);
. = DATA_SEGMENT_END (.);
/* Stabs debugging sections. */
.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) }
.comment 0 : { *(.comment) }
/* DWARF debug sections.
Symbols in the DWARF debugging sections are relative to the beginning
of the section so we begin them at 0. */
/* 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) }
/* 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) }
/DISCARD/ : { *(.note.GNU-stack) }
}
--
$ diff -u ~/src/binutils/ld/ldscripts/elf_i386.x a.lds
--- /home/me/src/binutils/ld/ldscripts/elf_i386.x 2003-09-11 21:47:13.000000000 -0400
+++ a.lds 2003-09-11 21:51:29.000000000 -0400
@@ -52,6 +63,9 @@
/* .gnu.warning sections are handled specially by elf32.em. */
*(.gnu.warning)
} =0x90909090
+ __initcall_start = .;
+ .initcall.init : { *(.initcall.init) }
+ __initcall_end = .;
.fini :
{
KEEP (*(.fini))
$
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