--- /dev/null
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 1999,2000,2001,2002,2003,2005,2006,2007 Free Software Foundation, Inc.
+ *
+ * GRUB 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+/*
+ * Note: These functions defined in this file may be called from C.
+ * Be careful of that you must not modify some registers. Quote
+ * from gcc-2.95.2/gcc/config/i386/i386.h:
+
+ 1 for registers not available across function calls.
+ These must include the FIXED_REGISTERS and also any
+ registers that can be used without being saved.
+ The latter must include the registers where values are returned
+ and the register where structure-value addresses are passed.
+ Aside from that, you can include as many other registers as you like.
+
+ ax,dx,cx,bx,si,di,bp,sp,st,st1,st2,st3,st4,st5,st6,st7,arg
+{ 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 }
+ */
+
+/*
+ * Note: GRUB is compiled with the options -mrtd and -mregparm=3.
+ * So the first three arguments are passed in %eax, %edx, and %ecx,
+ * respectively, and if a function has a fixed number of arguments
+ * and the number if greater than three, the function must return
+ * with "ret $N" where N is ((the number of arguments) - 3) * 4.
+ */
+
+/*
+ * This is the area for all of the special variables.
+ */
+
+ .p2align 2 /* force 4-byte alignment */
+
+/*
+ * void grub_linux_boot_zimage (void)
+ */
+VARIABLE(grub_linux_prot_size)
+ .long 0
+VARIABLE(grub_linux_tmp_addr)
+ .long 0
+VARIABLE(grub_linux_real_addr)
+ .long 0
+
+FUNCTION(grub_linux_boot_zimage)
+ /* copy the kernel */
+ movl EXT_C(grub_linux_prot_size), %ecx
+ addl $3, %ecx
+ shrl $2, %ecx
+ movl $GRUB_LINUX_BZIMAGE_ADDR, %esi
+ movl $GRUB_LINUX_ZIMAGE_ADDR, %edi
+ cld
+ rep
+ movsl
+
+FUNCTION(grub_linux_boot_bzimage)
+ call EXT_C(grub_dl_unload_all)
+
+ movl EXT_C(grub_linux_real_addr), %ebx
+
+ /* copy the real mode code */
+ movl EXT_C(grub_linux_tmp_addr), %esi
+ movl %ebx, %edi
+ movl $GRUB_LINUX_SETUP_MOVE_SIZE, %ecx
+ cld
+ rep
+ movsb
+
+ /* change %ebx to the segment address */
+ shrl $4, %ebx
+ movl %ebx, %eax
+ addl $0x20, %eax
+ movw %ax, linux_setup_seg
+
+ /* XXX new stack pointer in safe area for calling functions */
+ movl $0x4000, %esp
+ call EXT_C(grub_stop_floppy)
+
+ /* final setup for linux boot */
+ call prot_to_real
+ .code16
+
+ cli
+ movw %bx, %ss
+ movw $GRUB_LINUX_SETUP_STACK, %sp
+
+ movw %bx, %ds
+ movw %bx, %es
+ movw %bx, %fs
+ movw %bx, %gs
+
+ /* ljmp */
+ .byte 0xea
+ .word 0
+linux_setup_seg:
+ .word 0
+ .code32
+
+
+/*
+ * This starts the multiboot kernel.
+ */
+
+FUNCTION(grub_multiboot_real_boot)
+ /* Push the entry address on the stack. */
+ pushl %eax
+ /* Move the address of the multiboot information structure to ebx. */
+ movl %edx,%ebx
+
+ /* Unload all modules and stop the floppy driver. */
+ call EXT_C(grub_dl_unload_all)
+ call EXT_C(grub_stop_floppy)
+
+ /* Interrupts should be disabled. */
+ cli
+
+ /* Move the magic value into eax and jump to the kernel. */
+ movl $MULTIBOOT_MAGIC2,%eax
+ popl %ecx
+ jmp *%ecx
+
+/*
+ * This starts the multiboot 2 kernel.
+ */
+
+FUNCTION(grub_multiboot2_real_boot)
+ /* Push the entry address on the stack. */
+ pushl %eax
+ /* Move the address of the multiboot information structure to ebx. */
+ movl %edx,%ebx
+
+ /* Unload all modules and stop the floppy driver. */
+ call EXT_C(grub_dl_unload_all)
+ call EXT_C(grub_stop_floppy)
+
+ /* Interrupts should be disabled. */
+ cli
+
+ /* Move the magic value into eax and jump to the kernel. */
+ movl $MULTIBOOT2_BOOTLOADER_MAGIC,%eax
+ popl %ecx
+ jmp *%ecx
--- /dev/null
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 1999,2000,2001,2002,2003,2005,2006,2007 Free Software Foundation, Inc.
+ *
+ * GRUB 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+/*
+ * Note: These functions defined in this file may be called from C.
+ * Be careful of that you must not modify some registers. Quote
+ * from gcc-2.95.2/gcc/config/i386/i386.h:
+
+ 1 for registers not available across function calls.
+ These must include the FIXED_REGISTERS and also any
+ registers that can be used without being saved.
+ The latter must include the registers where values are returned
+ and the register where structure-value addresses are passed.
+ Aside from that, you can include as many other registers as you like.
+
+ ax,dx,cx,bx,si,di,bp,sp,st,st1,st2,st3,st4,st5,st6,st7,arg
+{ 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 }
+ */
+
+/*
+ * Note: GRUB is compiled with the options -mrtd and -mregparm=3.
+ * So the first three arguments are passed in %eax, %edx, and %ecx,
+ * respectively, and if a function has a fixed number of arguments
+ * and the number if greater than three, the function must return
+ * with "ret $N" where N is ((the number of arguments) - 3) * 4.
+ */
+
+/*
+ * This is the area for all of the special variables.
+ */
+
+ .p2align 2 /* force 4-byte alignment */
+
+protstack:
+ .long GRUB_MEMORY_MACHINE_PROT_STACK
+
+/*
+ * This is the Global Descriptor Table
+ *
+ * An entry, a "Segment Descriptor", looks like this:
+ *
+ * 31 24 19 16 7 0
+ * ------------------------------------------------------------
+ * | | |B| |A| | | |1|0|E|W|A| |
+ * | BASE 31..24 |G|/|L|V| LIMIT |P|DPL| TYPE | BASE 23:16 | 4
+ * | | |D| |L| 19..16| | |1|1|C|R|A| |
+ * ------------------------------------------------------------
+ * | | |
+ * | BASE 15..0 | LIMIT 15..0 | 0
+ * | | |
+ * ------------------------------------------------------------
+ *
+ * Note the ordering of the data items is reversed from the above
+ * description.
+ */
+
+ .p2align 2 /* force 4-byte alignment */
+gdt:
+ .word 0, 0
+ .byte 0, 0, 0, 0
+
+ /* -- code segment --
+ * base = 0x00000000, limit = 0xFFFFF (4 KiB Granularity), present
+ * type = 32bit code execute/read, DPL = 0
+ */
+ .word 0xFFFF, 0
+ .byte 0, 0x9A, 0xCF, 0
+
+ /* -- data segment --
+ * base = 0x00000000, limit 0xFFFFF (4 KiB Granularity), present
+ * type = 32 bit data read/write, DPL = 0
+ */
+ .word 0xFFFF, 0
+ .byte 0, 0x92, 0xCF, 0
+
+ /* -- 16 bit real mode CS --
+ * base = 0x00000000, limit 0x0FFFF (1 B Granularity), present
+ * type = 16 bit code execute/read only/conforming, DPL = 0
+ */
+ .word 0xFFFF, 0
+ .byte 0, 0x9E, 0, 0
+
+ /* -- 16 bit real mode DS --
+ * base = 0x00000000, limit 0x0FFFF (1 B Granularity), present
+ * type = 16 bit data read/write, DPL = 0
+ */
+ .word 0xFFFF, 0
+ .byte 0, 0x92, 0, 0
+
+
+/* this is the GDT descriptor */
+gdtdesc:
+ .word 0x27 /* limit */
+ .long gdt /* addr */
+
+/*
+ * These next routine, "prot_to_real" is structured in a very
+ * specific way. Be very careful when changing it.
+ *
+ * NOTE: Use of it messes up %eax and %ebp.
+ */
+
+prot_to_real:
+ /* just in case, set GDT */
+ lgdt gdtdesc
+
+ /* save the protected mode stack */
+ movl %esp, %eax
+ movl %eax, protstack
+
+ /* get the return address */
+ movl (%esp), %eax
+ movl %eax, GRUB_MEMORY_MACHINE_REAL_STACK
+
+ /* set up new stack */
+ movl $GRUB_MEMORY_MACHINE_REAL_STACK, %eax
+ movl %eax, %esp
+ movl %eax, %ebp
+
+ /* set up segment limits */
+ movw $GRUB_MEMORY_MACHINE_PSEUDO_REAL_DSEG, %ax
+ movw %ax, %ds
+ movw %ax, %es
+ movw %ax, %fs
+ movw %ax, %gs
+ movw %ax, %ss
+
+ /* this might be an extra step */
+ /* jump to a 16 bit segment */
+ ljmp $GRUB_MEMORY_MACHINE_PSEUDO_REAL_CSEG, $tmpcseg
+
+tmpcseg:
+ .code16
+
+ /* clear the PE bit of CR0 */
+ movl %cr0, %eax
+ andl $(~GRUB_MEMORY_MACHINE_CR0_PE_ON), %eax
+ movl %eax, %cr0
+
+ /* flush prefetch queue, reload %cs */
+ DATA32 ljmp $0, $realcseg
+
+realcseg:
+ /* we are in real mode now
+ * set up the real mode segment registers : DS, SS, ES
+ */
+ /* zero %eax */
+ xorl %eax, %eax
+
+ movw %ax, %ds
+ movw %ax, %es
+ movw %ax, %fs
+ movw %ax, %gs
+ movw %ax, %ss
+
+ /* restore interrupts */
+ sti
+
+ /* return on new stack! */
+ DATA32 ret
+
+ .code32
projects / thirdparty / grub.git / commitdiff
