u-boot-brain/arch/x86/include/asm/u-boot-x86.h
Graeme Russ 9e6c572ff0 x86: Use fs for global data
Use the base address of the 'F' segment as a pointer to the global data
structure. By adding the linear address (i.e. the 'D' segment address) as
the first word of the global data structure, the address of the global data
relative to the 'D' segment can be found simply, for example, by:

	fs movl 0, %eax

This makes the gd 'pointer' writable prior to relocation (by reloading the
Global Desctriptor Table) which brings x86 into line with all other arches

NOTE: Writing to the gd 'pointer' is expensive (but we only do it
twice) but using it to access global data members (read and write) is
still fairly cheap

--
Changes for v2:
 - Rebased against changes made to patch #3
 - Removed extra indent
 - Tweaked commit message
2012-01-04 22:17:24 +11:00

70 lines
2.0 KiB
C

/*
* (C) Copyright 2002
* Daniel Engström, Omicron Ceti AB, daniel@omicron.se.
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#ifndef _U_BOOT_I386_H_
#define _U_BOOT_I386_H_ 1
/* Exports from the Linker Script */
extern ulong __text_start;
extern ulong __data_end;
extern ulong __rel_dyn_start;
extern ulong __rel_dyn_end;
extern ulong __bss_start;
extern ulong __bss_end;
/* cpu/.../cpu.c */
int x86_cpu_init_r(void);
int cpu_init_r(void);
int x86_cpu_init_f(void);
int cpu_init_f(void);
void init_gd(gd_t *id, u64 *gdt_addr);
void setup_gdt(gd_t *id, u64 *gdt_addr);
/* cpu/.../timer.c */
void timer_isr(void *);
typedef void (timer_fnc_t) (void);
int register_timer_isr (timer_fnc_t *isr_func);
/* Architecture specific - can be in arch/x86/cpu/, arch/x86/lib/, or $(BOARD)/ */
int dram_init_f(void);
/* cpu/.../interrupts.c */
int cpu_init_interrupts(void);
/* board/.../... */
int dram_init(void);
void setup_pcat_compatibility(void);
void isa_unmap_rom(u32 addr);
u32 isa_map_rom(u32 bus_addr, int size);
/* arch/x86/lib/... */
int video_bios_init(void);
int video_init(void);
void board_init_f_r_trampoline(ulong) __attribute__ ((noreturn));
void board_init_f_r(void) __attribute__ ((noreturn));
#endif /* _U_BOOT_I386_H_ */