From 57a46d0579951d7abbcbe86766f73afa93a5d370 Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Thu, 12 Nov 2009 21:53:14 +0100 Subject: [PATCH] Convert linux bootrom to external rom and fw_cfg We already have a working multiboot implementation that uses fw_cfg to get its kernel module etc. data in int19 runtime now. So what's missing is a working linux boot option rom. While at it I figured it would be a good idea to take the opcode generator out of pc.c and instead use a proper option rom, like we do with multiboot. So here it is - an fw_cfg using option rom for -kernel with linux! Signed-off-by: Alexander Graf Signed-off-by: Anthony Liguori --- hw/fw_cfg.h | 8 +- hw/pc.c | 122 ++++++----------------------- pc-bios/linuxboot.bin | Bin 0 -> 1025 bytes pc-bios/optionrom/Makefile | 2 +- pc-bios/optionrom/linuxboot.S | 140 ++++++++++++++++++++++++++++++++++ 5 files changed, 170 insertions(+), 102 deletions(-) create mode 100644 pc-bios/linuxboot.bin create mode 100644 pc-bios/optionrom/linuxboot.S diff --git a/hw/fw_cfg.h b/hw/fw_cfg.h index 1e004b7070..7070c94010 100644 --- a/hw/fw_cfg.h +++ b/hw/fw_cfg.h @@ -20,7 +20,13 @@ #define FW_CFG_KERNEL_ENTRY 0x10 #define FW_CFG_KERNEL_DATA 0x11 #define FW_CFG_INITRD_DATA 0x12 -#define FW_CFG_MAX_ENTRY 0x13 +#define FW_CFG_CMDLINE_ADDR 0x13 +#define FW_CFG_CMDLINE_SIZE 0x14 +#define FW_CFG_CMDLINE_DATA 0x15 +#define FW_CFG_SETUP_ADDR 0x16 +#define FW_CFG_SETUP_SIZE 0x17 +#define FW_CFG_SETUP_DATA 0x18 +#define FW_CFG_MAX_ENTRY 0x19 #define FW_CFG_WRITE_CHANNEL 0x4000 #define FW_CFG_ARCH_LOCAL 0x8000 diff --git a/hw/pc.c b/hw/pc.c index 55bd1a48b2..7c791c4136 100644 --- a/hw/pc.c +++ b/hw/pc.c @@ -487,85 +487,6 @@ static void *bochs_bios_init(void) return fw_cfg; } -/* Generate an initial boot sector which sets state and jump to - a specified vector */ -static void generate_bootsect(uint32_t gpr[8], uint16_t segs[6], uint16_t ip) -{ - uint8_t rom[512], *p, *reloc; - uint8_t sum; - int i; - - memset(rom, 0, sizeof(rom)); - - p = rom; - /* Make sure we have an option rom signature */ - *p++ = 0x55; - *p++ = 0xaa; - - /* ROM size in sectors*/ - *p++ = 1; - - /* Hook int19 */ - - *p++ = 0x50; /* push ax */ - *p++ = 0x1e; /* push ds */ - *p++ = 0x31; *p++ = 0xc0; /* xor ax, ax */ - *p++ = 0x8e; *p++ = 0xd8; /* mov ax, ds */ - - *p++ = 0xc7; *p++ = 0x06; /* movvw _start,0x64 */ - *p++ = 0x64; *p++ = 0x00; - reloc = p; - *p++ = 0x00; *p++ = 0x00; - - *p++ = 0x8c; *p++ = 0x0e; /* mov cs,0x66 */ - *p++ = 0x66; *p++ = 0x00; - - *p++ = 0x1f; /* pop ds */ - *p++ = 0x58; /* pop ax */ - *p++ = 0xcb; /* lret */ - - /* Actual code */ - *reloc = (p - rom); - - *p++ = 0xfa; /* CLI */ - *p++ = 0xfc; /* CLD */ - - for (i = 0; i < 6; i++) { - if (i == 1) /* Skip CS */ - continue; - - *p++ = 0xb8; /* MOV AX,imm16 */ - *p++ = segs[i]; - *p++ = segs[i] >> 8; - *p++ = 0x8e; /* MOV ,AX */ - *p++ = 0xc0 + (i << 3); - } - - for (i = 0; i < 8; i++) { - *p++ = 0x66; /* 32-bit operand size */ - *p++ = 0xb8 + i; /* MOV ,imm32 */ - *p++ = gpr[i]; - *p++ = gpr[i] >> 8; - *p++ = gpr[i] >> 16; - *p++ = gpr[i] >> 24; - } - - *p++ = 0xea; /* JMP FAR */ - *p++ = ip; /* IP */ - *p++ = ip >> 8; - *p++ = segs[1]; /* CS */ - *p++ = segs[1] >> 8; - - /* sign rom */ - sum = 0; - for (i = 0; i < (sizeof(rom) - 1); i++) - sum += rom[i]; - rom[sizeof(rom) - 1] = -sum; - - rom_add_blob("linux-bootsect", rom, sizeof(rom), - PC_ROM_MIN_OPTION, PC_ROM_MAX, PC_ROM_ALIGN); -} - static long get_file_size(FILE *f) { long where, size; @@ -812,12 +733,9 @@ static void load_linux(void *fw_cfg, target_phys_addr_t max_ram_size) { uint16_t protocol; - uint32_t gpr[8]; - uint16_t seg[6]; - uint16_t real_seg; int setup_size, kernel_size, initrd_size = 0, cmdline_size; uint32_t initrd_max; - uint8_t header[8192], *setup, *kernel; + uint8_t header[8192], *setup, *kernel, *initrd_data; target_phys_addr_t real_addr, prot_addr, cmdline_addr, initrd_addr = 0; FILE *f; char *vmode; @@ -886,9 +804,11 @@ static void load_linux(void *fw_cfg, if (initrd_max >= max_ram_size-ACPI_DATA_SIZE) initrd_max = max_ram_size-ACPI_DATA_SIZE-1; - /* kernel command line */ - rom_add_blob_fixed("cmdline", kernel_cmdline, - strlen(kernel_cmdline)+1, cmdline_addr); + fw_cfg_add_i32(fw_cfg, FW_CFG_CMDLINE_ADDR, cmdline_addr); + fw_cfg_add_i32(fw_cfg, FW_CFG_CMDLINE_SIZE, strlen(kernel_cmdline)+1); + fw_cfg_add_bytes(fw_cfg, FW_CFG_CMDLINE_DATA, + (uint8_t*)strdup(kernel_cmdline), + strlen(kernel_cmdline)+1); if (protocol >= 0x202) { stl_p(header+0x228, cmdline_addr); @@ -937,7 +857,13 @@ static void load_linux(void *fw_cfg, initrd_size = get_image_size(initrd_filename); initrd_addr = (initrd_max-initrd_size) & ~4095; - rom_add_file_fixed(initrd_filename, initrd_addr); + + initrd_data = qemu_malloc(initrd_size); + load_image(initrd_filename, initrd_data); + + fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_ADDR, initrd_addr); + fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_SIZE, initrd_size); + fw_cfg_add_bytes(fw_cfg, FW_CFG_INITRD_DATA, initrd_data, initrd_size); stl_p(header+0x218, initrd_addr); stl_p(header+0x21c, initrd_size); @@ -957,21 +883,17 @@ static void load_linux(void *fw_cfg, fread(kernel, 1, kernel_size, f); fclose(f); memcpy(setup, header, MIN(sizeof(header), setup_size)); - rom_add_blob_fixed("linux-setup", setup, - setup_size, real_addr); - rom_add_blob_fixed(kernel_filename, kernel, - kernel_size, prot_addr); - qemu_free(setup); - qemu_free(kernel); - /* generate bootsector to set up the initial register state */ - real_seg = real_addr >> 4; - seg[0] = seg[2] = seg[3] = seg[4] = seg[4] = real_seg; - seg[1] = real_seg+0x20; /* CS */ - memset(gpr, 0, sizeof gpr); - gpr[4] = cmdline_addr-real_addr-16; /* SP (-16 is paranoia) */ + fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ADDR, prot_addr); + fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_SIZE, kernel_size); + fw_cfg_add_bytes(fw_cfg, FW_CFG_KERNEL_DATA, kernel, kernel_size); - generate_bootsect(gpr, seg, 0); + fw_cfg_add_i32(fw_cfg, FW_CFG_SETUP_ADDR, real_addr); + fw_cfg_add_i32(fw_cfg, FW_CFG_SETUP_SIZE, setup_size); + fw_cfg_add_bytes(fw_cfg, FW_CFG_SETUP_DATA, setup, setup_size); + + option_rom[nb_option_roms] = "linuxboot.bin"; + nb_option_roms++; } static const int ide_iobase[2] = { 0x1f0, 0x170 }; diff --git a/pc-bios/linuxboot.bin b/pc-bios/linuxboot.bin new file mode 100644 index 0000000000000000000000000000000000000000..d8f0ea80a26c9ff63ceb30839161a90a0ff7b0a7 GIT binary patch literal 1025 zcmeH_ze>YU6vj_Vs-=QS{nK`e;^uhYBo0C!zpIh-Gd@7~j!23$u(GEXnGUeVHV7~?gD=RBg dtM9U$epK1_DNCi-6Z+Dt$xr!T|CR%T_9uN&8yWxr literal 0 HcmV?d00001 diff --git a/pc-bios/optionrom/Makefile b/pc-bios/optionrom/Makefile index b01a54ec2d..54db882491 100644 --- a/pc-bios/optionrom/Makefile +++ b/pc-bios/optionrom/Makefile @@ -13,7 +13,7 @@ CFLAGS += -I$(SRC_PATH) CFLAGS += $(call cc-option, $(CFLAGS), -fno-stack-protector) QEMU_CFLAGS = $(CFLAGS) -build-all: multiboot.bin +build-all: multiboot.bin linuxboot.bin %.img: %.o $(call quiet-command,$(LD) -Ttext 0 -e _start -s -o $@ $<," Building $(TARGET_DIR)$@") diff --git a/pc-bios/optionrom/linuxboot.S b/pc-bios/optionrom/linuxboot.S new file mode 100644 index 0000000000..b3c90e33ce --- /dev/null +++ b/pc-bios/optionrom/linuxboot.S @@ -0,0 +1,140 @@ +/* + * Linux Boot Option ROM + * + * 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, see . + * + * Copyright Novell Inc, 2009 + * Authors: Alexander Graf + * + * Based on code in hw/pc.c. + */ + +#include "optionrom.h" + +BOOT_ROM_START + +run_linuxboot: + + cli + cld + + jmp copy_kernel +boot_kernel: + + read_fw FW_CFG_SETUP_ADDR + + mov %eax, %ebx + shr $4, %ebx + + /* All segments contain real_addr */ + mov %bx, %ds + mov %bx, %es + mov %bx, %fs + mov %bx, %gs + mov %bx, %ss + + /* CX = CS we want to jump to */ + add $0x20, %bx + mov %bx, %cx + + /* SP = cmdline_addr-real_addr-16 */ + read_fw FW_CFG_CMDLINE_ADDR + mov %eax, %ebx + read_fw FW_CFG_SETUP_ADDR + sub %eax, %ebx + sub $16, %ebx + mov %ebx, %esp + + /* Build indirect lret descriptor */ + pushw %cx /* CS */ + xor %ax, %ax + pushw %ax /* IP = 0 */ + + /* Clear registers */ + xor %eax, %eax + xor %ebx, %ebx + xor %ecx, %ecx + xor %edx, %edx + xor %edi, %edi + xor %ebp, %ebp + + /* Jump to Linux */ + lret + + +copy_kernel: + + /* We need to load the kernel into memory we can't access in 16 bit + mode, so let's get into 32 bit mode, write the kernel and jump + back again. */ + + /* Set DS to SS+SP - 0x10, so we can write our GDT descriptor there */ + mov %ss, %eax + shl $4, %eax + add %esp, %eax + sub $0x10, %eax + shr $4, %eax + + /* Now create the GDT descriptor */ + mov %cs, %eax + shl $4, %eax + movw $((3 * 8) - 1), %bx + movw %bx, %gs:0 + movl $gdt, %ebx + add %eax, %ebx + movl %ebx, %gs:2 + + /* And load the GDT */ + data32 lgdt %gs:0 + + /* Get us to protected mode now */ + mov $1, %eax + mov %eax, %cr0 + + /* So we can set DS to a 32-bit segment */ + mov $0x10, %eax + mov %eax, %ds + + /* We're now running in 16-bit CS, but 32-bit DS! */ + + /* Load kernel and initrd */ + read_fw_blob(FW_CFG_KERNEL) + read_fw_blob(FW_CFG_INITRD) + read_fw_blob(FW_CFG_CMDLINE) + read_fw_blob(FW_CFG_SETUP) + + /* And now jump into Linux! */ + mov $0, %eax + mov %eax, %cr0 + + /* DS = CS */ + mov %cs, %ax + mov %ax, %ds + + jmp boot_kernel + +/* Variables */ + +.align 4, 0 +gdt: + /* 0x00 */ +.byte 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 + + /* 0x08: code segment (base=0, limit=0xfffff, type=32bit code exec/read, DPL=0, 4k) */ +.byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x9a, 0xcf, 0x00 + + /* 0x10: data segment (base=0, limit=0xfffff, type=32bit data read/write, DPL=0, 4k) */ +.byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x92, 0xcf, 0x00 + +BOOT_ROM_END