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[Qemu-devel] [PATCH 5/6] Convert linux bootrom to external rom and fw_cf
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From: |
Alexander Graf |
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Subject: |
[Qemu-devel] [PATCH 5/6] Convert linux bootrom to external rom and fw_cfg |
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Date: |
Thu, 12 Nov 2009 21:53:14 +0100 |
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 <address@hidden>
---
hw/fw_cfg.h | 8 ++-
hw/pc.c | 126 +++++++------------------------------
pc-bios/optionrom/Makefile | 2 +-
pc-bios/optionrom/linuxboot.S | 140 +++++++++++++++++++++++++++++++++++++++++
4 files changed, 172 insertions(+), 104 deletions(-)
create mode 100644 pc-bios/optionrom/linuxboot.S
diff --git a/hw/fw_cfg.h b/hw/fw_cfg.h
index 1e004b7..7070c94 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 55bd1a4..7c791c4 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 <seg>,AX */
- *p++ = 0xc0 + (i << 3);
- }
-
- for (i = 0; i < 8; i++) {
- *p++ = 0x66; /* 32-bit operand size */
- *p++ = 0xb8 + i; /* MOV <reg>,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) */
-
- generate_bootsect(gpr, seg, 0);
+
+ 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);
+
+ 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/optionrom/Makefile b/pc-bios/optionrom/Makefile
index b01a54e..54db882 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 0000000..842dd3d
--- /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 <http://www.gnu.org/licenses/>.
+ *
+ * Copyright Novell Inc, 2009
+ * Authors: Alexander Graf <address@hidden>
+ *
+ * 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 retf 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 */
+ retf
+
+
+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
--
1.6.0.2
[Qemu-devel] [PATCH 4/6] Move common option rom code to header file, Alexander Graf, 2009/11/12
[Qemu-devel] [PATCH 3/6] Convert multiboot to fw_cfg backed data storage, Alexander Graf, 2009/11/12
[Qemu-devel] [PATCH 1/6] Make fw_cfg interface 32-bit aware, Alexander Graf, 2009/11/12