From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.69 #1 (Red Hat Linux)) id 1NUdrz-0007Go-6N for barebox@lists.infradead.org; Tue, 12 Jan 2010 10:21:08 +0000 Received: from octopus.hi.pengutronix.de ([2001:6f8:1178:2:215:17ff:fe12:23b0]) by metis.ext.pengutronix.de with esmtp (Exim 4.69) (envelope-from ) id 1NUdrr-0006W2-28 for barebox@lists.infradead.org; Tue, 12 Jan 2010 11:20:55 +0100 Received: from jbe by octopus.hi.pengutronix.de with local (Exim 4.69) (envelope-from ) id 1NUdrq-00070G-Up for barebox@lists.infradead.org; Tue, 12 Jan 2010 11:20:55 +0100 Message-Id: <20100112102054.844290281@pengutronix.de> References: <20100112101534.868276907@pengutronix.de> Date: Tue, 12 Jan 2010 11:15:41 +0100 From: Juergen Beisert Content-Disposition: inline; filename=add_boot_code.diff List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: barebox-bounces@lists.infradead.org Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCHv2 07/14] Add functions to be able to boot with BIOSs help To: barebox@lists.infradead.org These functions are special: They are running in the 16 bit real mode world to bring up barebox on an x86 box. Signed-off-by: Juergen Beisert --- arch/x86/boot/Kconfig | 20 ++++ arch/x86/boot/Makefile | 13 ++ arch/x86/boot/a20.c | 170 ++++++++++++++++++++++++++++++++++++ arch/x86/boot/bioscall.S | 99 +++++++++++++++++++++ arch/x86/boot/boot.h | 193 ++++++++++++++++++++++++++++++++++++++++++ arch/x86/boot/boot_hdisk.S | 176 ++++++++++++++++++++++++++++++++++++++ arch/x86/boot/boot_main.S | 58 ++++++++++++ arch/x86/boot/main_entry.c | 44 +++++++++ arch/x86/boot/pmjump.S | 89 +++++++++++++++++++ arch/x86/boot/prepare_uboot.c | 86 ++++++++++++++++++ arch/x86/boot/regs.c | 34 +++++++ arch/x86/boot/tty.c | 45 +++++++++ 12 files changed, 1027 insertions(+) Index: barebox-2009.12.0/arch/x86/boot/Kconfig =================================================================== --- /dev/null +++ barebox-2009.12.0/arch/x86/boot/Kconfig @@ -0,0 +1,20 @@ +if X86_BIOS_BRINGUP + +menu "BIOS boot source " + +config X86_HDBOOT + bool "HD boot" + help + Add code to boot from harddisk + +config X86_VESA + bool + default y if X86_GENERIC_HAS_VIDEO + +config X86_VGA + bool + default y if X86_GENERIC_HAS_VIDEO + +endmenu + +endif Index: barebox-2009.12.0/arch/x86/boot/Makefile =================================================================== --- /dev/null +++ barebox-2009.12.0/arch/x86/boot/Makefile @@ -0,0 +1,13 @@ + +CPPFLAGS += -D__I386__ -fno-strict-aliasing -m32 -g -Os -march=i386 \ + -mregparm=3 -fno-strict-aliasing -fomit-frame-pointer -ffreestanding \ + -fno-toplevel-reorder -fno-unit-at-a-time -fno-stack-protector \ + -mpreferred-stack-boundary=2 + +obj-$(CONFIG_X86_HDBOOT) += boot_main.o boot_hdisk.o + +obj-$(CONFIG_X86_BIOS_BRINGUP) += prepare_uboot.o a20.o bioscall.o regs.o tty.o pmjump.o main_entry.o + +obj-$(CONFIG_X86_VESA) += console_vesa.o +obj-$(CONFIG_X86_VGA) += console_vga.o +obj-$(CONFIG_X86_SERIAL) += console_serial.o Index: barebox-2009.12.0/arch/x86/boot/a20.c =================================================================== --- /dev/null +++ barebox-2009.12.0/arch/x86/boot/a20.c @@ -0,0 +1,170 @@ +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright 2007-2008 rPath, Inc. - All Rights Reserved + * Copyright 2009 Intel Corporation; author H. Peter Anvin + * + * This file is part of the Linux kernel, and is made available under + * the terms of the GNU General Public License version 2. + * + * ----------------------------------------------------------------------- */ + +/* + * Enable A20 gate (return -1 on failure) + */ + +#include +#include +#include "boot.h" + +#define MAX_8042_LOOPS 100000 +#define MAX_8042_FF 32 + +/* be aware of: */ +THIS_IS_REALMODE_CODE + +static int __bootcode empty_8042(void) +{ + u8 status; + int loops = MAX_8042_LOOPS; + int ffs = MAX_8042_FF; + + while (loops--) { + io_delay(); + + status = inb(0x64); + if (status == 0xff) { + /* FF is a plausible, but very unlikely status */ + if (!--ffs) + return -1; /* Assume no KBC present */ + } + if (status & 1) { + /* Read and discard input data */ + io_delay(); + (void)inb(0x60); + } else if (!(status & 2)) { + /* Buffers empty, finished! */ + return 0; + } + } + + return -1; +} + +/* Returns nonzero if the A20 line is enabled. The memory address + used as a test is the int $0x80 vector, which should be safe. */ + +#define A20_TEST_ADDR (4*0x80) +#define A20_TEST_SHORT 32 +#define A20_TEST_LONG 2097152 /* 2^21 */ + +static int __bootcode a20_test(int loops) +{ + int ok = 0; + int saved, ctr; + + set_fs(0x0000); + set_gs(0xffff); + + saved = ctr = rdfs32(A20_TEST_ADDR); + + while (loops--) { + wrfs32(++ctr, A20_TEST_ADDR); + io_delay(); /* Serialize and make delay constant */ + ok = rdgs32(A20_TEST_ADDR+0x10) ^ ctr; + if (ok) + break; + } + + wrfs32(saved, A20_TEST_ADDR); + return ok; +} + +/* Quick test to see if A20 is already enabled */ +static int __bootcode a20_test_short(void) +{ + return a20_test(A20_TEST_SHORT); +} + +/* Longer test that actually waits for A20 to come on line; this + is useful when dealing with the KBC or other slow external circuitry. */ +static int __bootcode a20_test_long(void) +{ + return a20_test(A20_TEST_LONG); +} + +static void __bootcode enable_a20_bios(void) +{ + struct biosregs ireg; + + initregs(&ireg); + ireg.ax = 0x2401; + intcall(0x15, &ireg, NULL); +} + +static void __bootcode enable_a20_kbc(void) +{ + empty_8042(); + + outb(0xd1, 0x64); /* Command write */ + empty_8042(); + + outb(0xdf, 0x60); /* A20 on */ + empty_8042(); + + outb(0xff, 0x64); /* Null command, but UHCI wants it */ + empty_8042(); +} + +static void __bootcode enable_a20_fast(void) +{ + u8 port_a; + + port_a = inb(0x92); /* Configuration port A */ + port_a |= 0x02; /* Enable A20 */ + port_a &= ~0x01; /* Do not reset machine */ + outb(port_a, 0x92); +} + +/* + * Actual routine to enable A20; return 0 on ok, -1 on failure + */ + +#define A20_ENABLE_LOOPS 255 /* Number of times to try */ + +int __bootcode enable_a20(void) +{ + int loops = A20_ENABLE_LOOPS; + int kbc_err; + + while (loops--) { + /* First, check to see if A20 is already enabled + (legacy free, etc.) */ + if (a20_test_short()) + return 0; + + /* Next, try the BIOS (INT 0x15, AX=0x2401) */ + enable_a20_bios(); + if (a20_test_short()) + return 0; + + /* Try enabling A20 through the keyboard controller */ + kbc_err = empty_8042(); + + if (a20_test_short()) + return 0; /* BIOS worked, but with delayed reaction */ + + if (!kbc_err) { + enable_a20_kbc(); + if (a20_test_long()) + return 0; + } + + /* Finally, try enabling the "fast A20 gate" */ + enable_a20_fast(); + if (a20_test_long()) + return 0; + } + + return -1; +} Index: barebox-2009.12.0/arch/x86/boot/bioscall.S =================================================================== --- /dev/null +++ barebox-2009.12.0/arch/x86/boot/bioscall.S @@ -0,0 +1,99 @@ +/* ----------------------------------------------------------------------- + * + * Copyright 2009 Intel Corporation; author H. Peter Anvin + * + * This file is part of the Linux kernel, and is made available under + * the terms of the GNU General Public License version 2 or (at your + * option) any later version; incorporated herein by reference. + * + * ----------------------------------------------------------------------- */ + +/* + * "Glove box" for BIOS calls. Avoids the constant problems with BIOSes + * touching registers they shouldn't be. + */ + +#ifndef DOXYGEN_SHOULD_SKIP_THIS + + .file "bioscall.S" + .code16 + .section .boot.text.intcall, "ax" + + .globl intcall + .type intcall, @function +intcall: + /* Self-modify the INT instruction. Ugly, but works. */ + cmpb %al, 3f + je 1f + movb %al, 3f + jmp 1f /* Synchronize pipeline */ +1: + /* Save state */ + pushfl + pushw %fs + pushw %gs + pushal + + /* Copy input state to stack frame */ + subw $44, %sp + movw %dx, %si + movw %sp, %di + movw $11, %cx + rep; movsd + + /* Pop full state from the stack */ + popal + popw %gs + popw %fs + popw %es + popw %ds + popfl + + /* Actual INT */ + .byte 0xcd /* INT opcode */ +3: .byte 0 + + /* Push full state to the stack */ + pushfl + pushw %ds + pushw %es + pushw %fs + pushw %gs + pushal + + /* Re-establish C environment invariants */ + cld + movzwl %sp, %esp + movw %cs, %ax + movw %ax, %ds + movw %ax, %es + + /* Copy output state from stack frame */ + movw 68(%esp), %di /* Original %cx == 3rd argument */ + andw %di, %di + jz 4f + movw %sp, %si + movw $11, %cx + rep; movsd +4: addw $44, %sp + + /* Restore state and return */ + popal + popw %gs + popw %fs + popfl + retl + .size intcall, .-intcall + +/* ------------------------------------------------------------------------ */ + .code16 + .section .boot.text.die, "ax" + + .globl die + .type die, @function +die: + hlt + jmp die + .size die, .-die + +#endif /* DOXYGEN_SHOULD_SKIP_THIS */ Index: barebox-2009.12.0/arch/x86/boot/boot.h =================================================================== --- /dev/null +++ barebox-2009.12.0/arch/x86/boot/boot.h @@ -0,0 +1,193 @@ +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright 2007 rPath, Inc. - All Rights Reserved + * Copyright 2009 Intel Corporation; author H. Peter Anvin + * + * This file is part of the Linux kernel, and is made available under + * the terms of the GNU General Public License version 2. + * + * ----------------------------------------------------------------------- */ + +/** + * @file + * @brief Main declarations for the real mode code + */ + +#ifndef BOOT_BOOT_H +#define BOOT_BOOT_H + +#define STACK_SIZE 512 /* Minimum number of bytes for stack */ + +/** Carry flag */ +#define X86_EFLAGS_CF 0x00000001 + +/** PE flag */ +#define X86_CR0_PE 0x00000001 + +#ifndef __ASSEMBLY__ + +#include + +/* we are still in real mode here! */ +#define THIS_IS_REALMODE_CODE asm(".code16gcc"); + +struct biosregs { + union { + struct { + uint32_t edi; + uint32_t esi; + uint32_t ebp; + uint32_t _esp; + uint32_t ebx; + uint32_t edx; + uint32_t ecx; + uint32_t eax; + uint32_t _fsgs; + uint32_t _dses; + uint32_t eflags; + }; + struct { + uint16_t di, hdi; + uint16_t si, hsi; + uint16_t bp, hbp; + uint16_t _sp, _hsp; + uint16_t bx, hbx; + uint16_t dx, hdx; + uint16_t cx, hcx; + uint16_t ax, hax; + uint16_t gs, fs; + uint16_t es, ds; + uint16_t flags, hflags; + }; + struct { + uint8_t dil, dih, edi2, edi3; + uint8_t sil, sih, esi2, esi3; + uint8_t bpl, bph, ebp2, ebp3; + uint8_t _spl, _sph, _esp2, _esp3; + uint8_t bl, bh, ebx2, ebx3; + uint8_t dl, dh, edx2, edx3; + uint8_t cl, ch, ecx2, ecx3; + uint8_t al, ah, eax2, eax3; + }; + }; +}; + +/* functions in the realmode part */ +extern int enable_a20(void); +extern void initregs(struct biosregs *regs); +extern void intcall(uint8_t int_no, const struct biosregs *ireg, struct biosregs *oreg); +extern void boot_puts(char*); +extern void __attribute__((noreturn)) die(void); +extern void __attribute__((noreturn)) protected_mode_jump(void); + +struct gdt_ptr { + uint16_t len; + uint32_t ptr; +} __attribute__((packed)); + +/* These functions are used to reference data in other segments. */ + +static inline uint16_t ds(void) +{ + uint16_t seg; + asm("movw %%ds,%0" : "=rm" (seg)); + return seg; +} + +static inline void set_fs(uint16_t seg) +{ + asm volatile("movw %0,%%fs" : : "rm" (seg)); +} + +static inline uint16_t fs(void) +{ + uint16_t seg; + asm volatile("movw %%fs,%0" : "=rm" (seg)); + return seg; +} + +static inline void set_gs(uint16_t seg) +{ + asm volatile("movw %0,%%gs" : : "rm" (seg)); +} + +static inline uint16_t gs(void) +{ + uint16_t seg; + asm volatile("movw %%gs,%0" : "=rm" (seg)); + return seg; +} + +typedef unsigned int addr_t; + +static inline uint8_t rdfs8(addr_t addr) +{ + uint8_t v; + asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*(uint8_t *)addr)); + return v; +} +static inline uint16_t rdfs16(addr_t addr) +{ + uint16_t v; + asm volatile("movw %%fs:%1,%0" : "=r" (v) : "m" (*(uint16_t *)addr)); + return v; +} +static inline uint32_t rdfs32(addr_t addr) +{ + uint32_t v; + asm volatile("movl %%fs:%1,%0" : "=r" (v) : "m" (*(uint32_t *)addr)); + return v; +} + +static inline void wrfs8(uint8_t v, addr_t addr) +{ + asm volatile("movb %1,%%fs:%0" : "+m" (*(uint8_t *)addr) : "qi" (v)); +} +static inline void wrfs16(uint16_t v, addr_t addr) +{ + asm volatile("movw %1,%%fs:%0" : "+m" (*(uint16_t *)addr) : "ri" (v)); +} +static inline void wrfs32(uint32_t v, addr_t addr) +{ + asm volatile("movl %1,%%fs:%0" : "+m" (*(uint32_t *)addr) : "ri" (v)); +} + +static inline uint8_t rdgs8(addr_t addr) +{ + uint8_t v; + asm volatile("movb %%gs:%1,%0" : "=q" (v) : "m" (*(uint8_t *)addr)); + return v; +} +static inline uint16_t rdgs16(addr_t addr) +{ + uint16_t v; + asm volatile("movw %%gs:%1,%0" : "=r" (v) : "m" (*(uint16_t *)addr)); + return v; +} +static inline uint32_t rdgs32(addr_t addr) +{ + uint32_t v; + asm volatile("movl %%gs:%1,%0" : "=r" (v) : "m" (*(uint32_t *)addr)); + return v; +} + +static inline void wrgs8(uint8_t v, addr_t addr) +{ + asm volatile("movb %1,%%gs:%0" : "+m" (*(uint8_t *)addr) : "qi" (v)); +} +static inline void wrgs16(uint16_t v, addr_t addr) +{ + asm volatile("movw %1,%%gs:%0" : "+m" (*(uint16_t *)addr) : "ri" (v)); +} +static inline void wrgs32(uint32_t v, addr_t addr) +{ + asm volatile("movl %1,%%gs:%0" : "+m" (*(uint32_t *)addr) : "ri" (v)); +} + +/** use the built in memset function for the real mode code */ +#define memset(d,c,l) __builtin_memset(d,c,l) + +#endif /* __ASSEMBLY__ */ + +#endif /* BOOT_BOOT_H */ Index: barebox-2009.12.0/arch/x86/boot/boot_hdisk.S =================================================================== --- /dev/null +++ barebox-2009.12.0/arch/x86/boot/boot_hdisk.S @@ -0,0 +1,176 @@ +/* + * Copyright (C) 2009 Juergen Beisert, Pengutronix + * + * This code was inspired by the GRUB2 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 + * + */ + +/** + * @file + * @brief Loading the barebox image from a disk drive in LBA mode + */ + +/** + * @fn void real_start(void) + * @brief A very simple and small loader to fetch all required sectors + * from the boot media. + */ + +#ifndef DOXYGEN_SHOULD_SKIP_THIS + + .file "boot_hdisk.S" + .code16 + + /* + * These symbols are generated by the linker, because they need a + * special layout. This layout is needed to be able to setup this + * bootloader by patching the binary when it gets stored into the + * master boot record. + */ + .extern indirect_sector_lba + .extern boot_stack + .extern start_pre_uboot + .extern boot_disk + .section .boot_code, "ax" + + .globl real_start + .type real_start, @function + +real_start: + + xorw %ax, %ax /* set up %ds and %ss as offset from 0 */ + movw %ax, %ds + movw %ax, %ss + + /* set up the REAL stack */ + movw $boot_stack, %sp + + sti /* we're safe again */ + + /* save drive reference first thing! */ + movb %dl, boot_disk + pushw %dx + + movw $notification_string, %si + call output_message + + /* + * This boot code only supports LBA. We fail here, if the BIOS + * does not support LBA for the harddisk + */ + + /* check if LBA is supported */ + movb $0x41, %ah + movw $0x55aa, %bx + int $0x13 + + /* + * %dl may have been clobbered by INT 13, AH=41H. + * This happens, for example, with AST BIOS 1.04. + */ + popw %dx + pushw %dx + + /* stop if no LBA support */ + jc no_lba + cmpw $0xaa55, %bx + jne no_lba + andw $1, %cx + jz no_lba + +lba_mode: + /* + * Load the indirect sector. Its content is ready for use, + * provided by the installer + */ + movw $indirect_sector_lba, %si + movb $0x42, %ah + int $0x13 + jc no_lba /* error? Then die */ + + /* + * Now loop through all valid entries in the indirect sector + */ + movw $indirect_area, %si + +load_loop: + /* + * Stop if this "Disk Address Packet Structure" is invalid + * We call it invalid, if the size member is zero. If it is invalid + * we are optimistic and calling the loaded image + */ + movw (%si), %ax + cmpw $0x0000, %ax + je start_main + + /* + * Load this entry + */ + movb $0x42, %ah + int $0x13 + jc no_lba + + addw (%si), %si /* next entry */ + cmpw $indirect_area + 512, %si + jne load_loop + /* + * fall through to start u-boot. + */ +start_main: + movw $jmp_string, %si + call output_message + jmp start_pre_uboot +/* + * die if there is no LBA support + */ +no_lba: movw $chs_string, %si + call output_message + hlt + +/* + * message: write the string pointed to by %si + * + * WARNING: trashes %si, %ax, and %bx + */ + +/* + * Use BIOS "int 10H Function 0Eh" to write character in teletype mode + * %ah = 0xe %al = character + * %bh = page %bl = foreground color (graphics modes) + */ + +1: + movw $0x0001, %bx + movb $0xe, %ah + int $0x10 /* display this char */ + +output_message: + lodsb + cmpb $0, %al + jne 1b /* if not end of string, next char */ + ret + +/* ---------------------------------------------------------------------- */ + + .section .boot_data + +notification_string: .asciz "UBOOT2 " +chs_string: .asciz "CHS " +jmp_string: .asciz "JMP " + +#endif Index: barebox-2009.12.0/arch/x86/boot/boot_main.S =================================================================== --- /dev/null +++ barebox-2009.12.0/arch/x86/boot/boot_main.S @@ -0,0 +1,58 @@ +/* + * Copyright (C) 2009 Juergen Beisert, Pengutronix + * + * This code was inspired by the GRUB2 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 + * + */ + +/** + * @file + * @brief Common boot sector main routine to be entered by the BIOS + */ +/** + * @fn void _start(void) + * + * @brief Fix segment:offset settings of some buggy BIOSs + */ + +#ifndef DOXYGEN_SHOULD_SKIP_THIS + + .file "boot_main.S" + .code16 + + .extern real_start + + .section .boot_start, "ax" + .type _start, @function + + /* + * The BIOS loads this code to address 0x00007c00. + * The code should be called with CS:IP 0:0x7c00 (hopefully). + */ + .globl _start +_start: + cli /* we're not safe here! */ + /* + * It seems there are implementations in the wild which call this + * code with CS:IP 0x07C0:0000 instead. We fix it immediately. + */ + ljmp $0, $real_start + + .size _start, .-_start + +#endif Index: barebox-2009.12.0/arch/x86/boot/main_entry.c =================================================================== --- /dev/null +++ barebox-2009.12.0/arch/x86/boot/main_entry.c @@ -0,0 +1,44 @@ +/* + * Copyright (C) 2009 Juergen Beisert, Pengutronix + * + * 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 + * + */ + +/** + * @file + * @brief Start of the 32 bit flat mode + */ + +#include + +/* These symbols are generated by the linker */ +extern char __bss_start; +extern char __bss_end; + +extern void start_barebox(void); + +/** + * Called plainly from assembler that switches from real to flat mode + * + * @note The C environment isn't initialized yet + */ +void uboot_entry(void) +{ + /* clear the BSS first */ + memset(&__bss_start, 0x00, &__bss_end - &__bss_start); + start_barebox(); +} Index: barebox-2009.12.0/arch/x86/boot/pmjump.S =================================================================== --- /dev/null +++ barebox-2009.12.0/arch/x86/boot/pmjump.S @@ -0,0 +1,89 @@ +/* ----------------------------------------------------------------------- * + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright 2007 rPath, Inc. - All Rights Reserved + * + * This file is part of the Linux kernel, and is made available under + * the terms of the GNU General Public License version 2. + * + * ----------------------------------------------------------------------- */ + +/** + * @file + * @brief The actual transition into protected mode + * + * Note: This function is running in flat and real mode. Due to some + * other restrictions it must running from an address space below 0x10000 + */ + +/** + * @fn void protected_mode_jump(void) + * @brief Switches the first time from real mode to flat mode + */ +#ifndef DOXYGEN_SHOULD_SKIP_THIS + +#include +#include "boot.h" + + .file "pmjump.S" + .code16 + .section .boot.text.protected_mode_jump, "ax" + + .globl protected_mode_jump + .type protected_mode_jump, @function + +protected_mode_jump: + jmp 1f /* Short jump to serialize on 386/486 */ +1: + + movw $__BOOT_DS, %cx + movw $__BOOT_TSS, %di + + movl %cr0, %edx + orb $X86_CR0_PE, %dl /* enable protected mode */ + movl %edx, %cr0 + + /* Transition to 32-bit flat mode */ + data32 ljmp $__BOOT_CS, $in_pm32 + +/* ------------------------------------------------------------------------ */ + + .section ".text.in_pm32","ax" + .code32 + + .extern uboot_entry + .extern __bss_end + + .type in_pm32, @function +in_pm32: + # Set up data segments for flat 32-bit mode + movl %ecx, %ds + movl %ecx, %es + movl %ecx, %fs + movl %ecx, %gs + movl %ecx, %ss +/* + * Our flat mode code uses its own stack area behind the bss. With this we + * are still able to return to real mode temporarely + */ + movl $__bss_end + 32768, %esp + + # Set up TR to make Intel VT happy + ltr %di + + # Clear registers to allow for future extensions to the + # 32-bit boot protocol + xorl %ecx, %ecx + xorl %edx, %edx + xorl %ebx, %ebx + xorl %ebp, %ebp + xorl %edi, %edi + + # Set up LDTR to make Intel VT happy + lldt %cx + + jmp uboot_entry + + .size protected_mode_jump, .-protected_mode_jump + +#endif Index: barebox-2009.12.0/arch/x86/boot/prepare_uboot.c =================================================================== --- /dev/null +++ barebox-2009.12.0/arch/x86/boot/prepare_uboot.c @@ -0,0 +1,86 @@ +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright 2007 rPath, Inc. - All Rights Reserved + * + * This file is part of the Linux kernel, and is made available under + * the terms of the GNU General Public License version 2. + * + * ----------------------------------------------------------------------- */ + +/* + * Prepare the machine for transition to protected mode. + */ +#include +#include +#include +#include "boot.h" + +/* be aware of: */ +THIS_IS_REALMODE_CODE + +/* + * While we are in flat mode, we can't handle interrupts. But we can't + * switch them off for ever in the PIC, because we need them again while + * entering real mode code again and again.... + */ +static void __bootcode realmode_switch_hook(void) +{ + asm volatile("cli"); + outb(0x80, 0x70); /* Disable NMI */ + io_delay(); +} + +/* + * Reset IGNNE# if asserted in the FPU. + */ +static void __bootcode reset_coprocessor(void) +{ + outb(0, 0xf0); + io_delay(); + outb(0, 0xf1); + io_delay(); +} + +/** + * Setup and register the global descriptor table (GDT) + * + * @note This is for the first time only + */ +static void __bootcode setup_gdt(void) +{ + /* Xen HVM incorrectly stores a pointer to the gdt_ptr, instead + of the gdt_ptr contents. Thus, make it static so it will + stay in memory, at least long enough that we switch to the + proper kernel GDT. */ + static struct gdt_ptr __bootdata gdt_ptr; + + gdt_ptr.len = gdt_size - 1; + gdt_ptr.ptr = (uint32_t)&gdt + (ds() << 4); + + asm volatile("lgdtl %0" : : "m" (gdt_ptr)); +} + +static char a20_message[] __bootdata = "A20 gate not responding, unable to boot...\n"; + +/* + * Actual invocation sequence + */ +void __bootcode start_pre_uboot(void) +{ + /* Hook before leaving real mode, also disables interrupts */ + realmode_switch_hook(); + + /* Enable the A20 gate */ + if (enable_a20()) { + boot_puts(a20_message); + die(); + } + + /* Reset coprocessor (IGNNE#) */ + reset_coprocessor(); + + setup_gdt(); + /* Actual transition to protected mode... */ + protected_mode_jump(); +} Index: barebox-2009.12.0/arch/x86/boot/regs.c =================================================================== --- /dev/null +++ barebox-2009.12.0/arch/x86/boot/regs.c @@ -0,0 +1,34 @@ +/* ----------------------------------------------------------------------- + * + * Copyright 2009 Intel Corporation; author H. Peter Anvin + * + * This file is part of the Linux kernel, and is made available under + * the terms of the GNU General Public License version 2 or (at your + * option) any later version; incorporated herein by reference. + * + * ----------------------------------------------------------------------- */ + +/** + * @file + * @brief Simple helper function for initializing a register set. + * + * Note that this sets EFLAGS_CF in the input register set; this + * makes it easier to catch functions which do nothing but don't + * explicitly set CF. + */ + +#include +#include "boot.h" + +/* be aware of: */ +THIS_IS_REALMODE_CODE + +void __bootcode initregs(struct biosregs *reg) +{ + memset(reg, 0, sizeof *reg); + reg->eflags |= X86_EFLAGS_CF; + reg->ds = ds(); + reg->es = ds(); + reg->fs = fs(); + reg->gs = gs(); +} Index: barebox-2009.12.0/arch/x86/boot/tty.c =================================================================== --- /dev/null +++ barebox-2009.12.0/arch/x86/boot/tty.c @@ -0,0 +1,45 @@ +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright 2007 rPath, Inc. - All Rights Reserved + * Copyright 2009 Intel Corporation; author H. Peter Anvin + * + * This file is part of the Linux kernel, and is made available under + * the terms of the GNU General Public License version 2. + * + * ----------------------------------------------------------------------- */ + +/** + * @file + * @brief Very simple screen I/O for the initialization stage + * + * @todo Probably should add very simple serial I/O? + * @attention This is real mode code! + */ + +#include +#include "boot.h" + +/* be aware of: */ +THIS_IS_REALMODE_CODE + +static void __bootcode putchar(int ch) +{ + struct biosregs ireg; + + if (ch == '\n') + putchar('\r'); /* \n -> \r\n */ + + initregs(&ireg); + ireg.bx = 0x0007; + ireg.cx = 0x0001; + ireg.ah = 0x0e; + ireg.al = ch; + intcall(0x10, &ireg, NULL); +} + +void __bootcode boot_puts(char *str) +{ + while (*str) + putchar(*str++); +} -- _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox