kernel_optimize_test/include/asm-generic/vmlinux.lds.h
Vivek Goyal 6569580de7 [PATCH] i386: Distinguish absolute symbols
Ld knows about 2 kinds of symbols,  absolute and section
relative.  Section relative symbols symbols change value
when a section is moved and absolute symbols do not.

Currently in the linker script we have several labels
marking the beginning and ending of sections that
are outside of sections, making them absolute symbols.
Having a mixture of absolute and section relative
symbols refereing to the same data is currently harmless
but it is confusing.

This must be done carefully as newer revs of ld do not place
symbols that appear in sections without data and instead
ld makes those symbols global :(

My ultimate goal is to build a relocatable kernel.  The
safest and least intrusive technique is to generate
relocation entries so the kernel can be relocated at load
time.  The only penalty would be an increase in the size
of the kernel binary.  The problem is that if absolute and
relocatable symbols are not properly specified absolute symbols
will be relocated or section relative symbols won't be, which
is fatal.

The practical motivation is that when generating kernels that
will run from a reserved area for analyzing what caused
a kernel panic, it is simpler if you don't need to hard code
the physical memory location they will run at, especially
for the distributions.

[AK: and merged:]

o Also put a message so that in future people can be aware of it and
  avoid introducing absolute symbols.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
2006-12-07 02:14:03 +01:00

235 lines
7.8 KiB
C

#ifndef LOAD_OFFSET
#define LOAD_OFFSET 0
#endif
#ifndef VMLINUX_SYMBOL
#define VMLINUX_SYMBOL(_sym_) _sym_
#endif
/* Align . to a 8 byte boundary equals to maximum function alignment. */
#define ALIGN_FUNCTION() . = ALIGN(8)
#define RODATA \
. = ALIGN(4096); \
.rodata : AT(ADDR(.rodata) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start_rodata) = .; \
*(.rodata) *(.rodata.*) \
*(__vermagic) /* Kernel version magic */ \
} \
\
.rodata1 : AT(ADDR(.rodata1) - LOAD_OFFSET) { \
*(.rodata1) \
} \
\
/* PCI quirks */ \
.pci_fixup : AT(ADDR(.pci_fixup) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start_pci_fixups_early) = .; \
*(.pci_fixup_early) \
VMLINUX_SYMBOL(__end_pci_fixups_early) = .; \
VMLINUX_SYMBOL(__start_pci_fixups_header) = .; \
*(.pci_fixup_header) \
VMLINUX_SYMBOL(__end_pci_fixups_header) = .; \
VMLINUX_SYMBOL(__start_pci_fixups_final) = .; \
*(.pci_fixup_final) \
VMLINUX_SYMBOL(__end_pci_fixups_final) = .; \
VMLINUX_SYMBOL(__start_pci_fixups_enable) = .; \
*(.pci_fixup_enable) \
VMLINUX_SYMBOL(__end_pci_fixups_enable) = .; \
} \
\
/* RapidIO route ops */ \
.rio_route : AT(ADDR(.rio_route) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start_rio_route_ops) = .; \
*(.rio_route_ops) \
VMLINUX_SYMBOL(__end_rio_route_ops) = .; \
} \
\
/* Kernel symbol table: Normal symbols */ \
__ksymtab : AT(ADDR(__ksymtab) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___ksymtab) = .; \
*(__ksymtab) \
VMLINUX_SYMBOL(__stop___ksymtab) = .; \
} \
\
/* Kernel symbol table: GPL-only symbols */ \
__ksymtab_gpl : AT(ADDR(__ksymtab_gpl) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___ksymtab_gpl) = .; \
*(__ksymtab_gpl) \
VMLINUX_SYMBOL(__stop___ksymtab_gpl) = .; \
} \
\
/* Kernel symbol table: Normal unused symbols */ \
__ksymtab_unused : AT(ADDR(__ksymtab_unused) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___ksymtab_unused) = .; \
*(__ksymtab_unused) \
VMLINUX_SYMBOL(__stop___ksymtab_unused) = .; \
} \
\
/* Kernel symbol table: GPL-only unused symbols */ \
__ksymtab_unused_gpl : AT(ADDR(__ksymtab_unused_gpl) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___ksymtab_unused_gpl) = .; \
*(__ksymtab_unused_gpl) \
VMLINUX_SYMBOL(__stop___ksymtab_unused_gpl) = .; \
} \
\
/* Kernel symbol table: GPL-future-only symbols */ \
__ksymtab_gpl_future : AT(ADDR(__ksymtab_gpl_future) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___ksymtab_gpl_future) = .; \
*(__ksymtab_gpl_future) \
VMLINUX_SYMBOL(__stop___ksymtab_gpl_future) = .; \
} \
\
/* Kernel symbol table: Normal symbols */ \
__kcrctab : AT(ADDR(__kcrctab) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___kcrctab) = .; \
*(__kcrctab) \
VMLINUX_SYMBOL(__stop___kcrctab) = .; \
} \
\
/* Kernel symbol table: GPL-only symbols */ \
__kcrctab_gpl : AT(ADDR(__kcrctab_gpl) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___kcrctab_gpl) = .; \
*(__kcrctab_gpl) \
VMLINUX_SYMBOL(__stop___kcrctab_gpl) = .; \
} \
\
/* Kernel symbol table: Normal unused symbols */ \
__kcrctab_unused : AT(ADDR(__kcrctab_unused) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___kcrctab_unused) = .; \
*(__kcrctab_unused) \
VMLINUX_SYMBOL(__stop___kcrctab_unused) = .; \
} \
\
/* Kernel symbol table: GPL-only unused symbols */ \
__kcrctab_unused_gpl : AT(ADDR(__kcrctab_unused_gpl) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___kcrctab_unused_gpl) = .; \
*(__kcrctab_unused_gpl) \
VMLINUX_SYMBOL(__stop___kcrctab_unused_gpl) = .; \
} \
\
/* Kernel symbol table: GPL-future-only symbols */ \
__kcrctab_gpl_future : AT(ADDR(__kcrctab_gpl_future) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___kcrctab_gpl_future) = .; \
*(__kcrctab_gpl_future) \
VMLINUX_SYMBOL(__stop___kcrctab_gpl_future) = .; \
} \
\
/* Kernel symbol table: strings */ \
__ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) { \
*(__ksymtab_strings) \
} \
\
/* Unwind data binary search table */ \
EH_FRAME_HDR \
\
/* Built-in module parameters. */ \
__param : AT(ADDR(__param) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___param) = .; \
*(__param) \
VMLINUX_SYMBOL(__stop___param) = .; \
VMLINUX_SYMBOL(__end_rodata) = .; \
} \
\
. = ALIGN(4096);
#define SECURITY_INIT \
.security_initcall.init : AT(ADDR(.security_initcall.init) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__security_initcall_start) = .; \
*(.security_initcall.init) \
VMLINUX_SYMBOL(__security_initcall_end) = .; \
}
/* sched.text is aling to function alignment to secure we have same
* address even at second ld pass when generating System.map */
#define SCHED_TEXT \
ALIGN_FUNCTION(); \
VMLINUX_SYMBOL(__sched_text_start) = .; \
*(.sched.text) \
VMLINUX_SYMBOL(__sched_text_end) = .;
/* spinlock.text is aling to function alignment to secure we have same
* address even at second ld pass when generating System.map */
#define LOCK_TEXT \
ALIGN_FUNCTION(); \
VMLINUX_SYMBOL(__lock_text_start) = .; \
*(.spinlock.text) \
VMLINUX_SYMBOL(__lock_text_end) = .;
#define KPROBES_TEXT \
ALIGN_FUNCTION(); \
VMLINUX_SYMBOL(__kprobes_text_start) = .; \
*(.kprobes.text) \
VMLINUX_SYMBOL(__kprobes_text_end) = .;
#ifdef CONFIG_STACK_UNWIND
/* Unwind data binary search table */
#define EH_FRAME_HDR \
.eh_frame_hdr : AT(ADDR(.eh_frame_hdr) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start_unwind_hdr) = .; \
*(.eh_frame_hdr) \
VMLINUX_SYMBOL(__end_unwind_hdr) = .; \
}
#else
#define EH_FRAME_HDR
#endif
/* DWARF debug sections.
Symbols in the DWARF debugging sections are relative to
the beginning of the section so we begin them at 0. */
#define DWARF_DEBUG \
/* 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) } \
/* Stabs debugging sections. */
#define STABS_DEBUG \
.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) }
#define NOTES \
.notes : { *(.note.*) } :note
#define INITCALLS \
*(.initcall0.init) \
*(.initcall0s.init) \
*(.initcall1.init) \
*(.initcall1s.init) \
*(.initcall2.init) \
*(.initcall2s.init) \
*(.initcall3.init) \
*(.initcall3s.init) \
*(.initcall4.init) \
*(.initcall4s.init) \
*(.initcall5.init) \
*(.initcall5s.init) \
*(.initcall6.init) \
*(.initcall6s.init) \
*(.initcall7.init) \
*(.initcall7s.init)