diff options
Diffstat (limited to 'pc-bios/optionrom/pvh.S')
| -rw-r--r-- | pc-bios/optionrom/pvh.S | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/pc-bios/optionrom/pvh.S b/pc-bios/optionrom/pvh.S new file mode 100644 index 0000000000..e1d7f4a7a7 --- /dev/null +++ b/pc-bios/optionrom/pvh.S @@ -0,0 +1,200 @@ +/* + * PVH 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 <agraf@suse.de> + * + * Copyright (c) 2019 Red Hat Inc. + * Authors: Stefano Garzarella <sgarzare@redhat.com> + */ + +#include "optionrom.h" + +#define BOOT_ROM_PRODUCT "PVH loader" + +#define GS_PROT_JUMP 0 +#define GS_GDT_DESC 6 + +#ifdef OPTION_ROM_START +#undef OPTION_ROM_START +#endif +#ifdef OPTION_ROM_END +#undef OPTION_ROM_END +#endif + +/* + * Redefine OPTION_ROM_START and OPTION_ROM_END, because this rom is produced + * linking multiple objects. + * signrom.py will add padding. + */ +#define OPTION_ROM_START \ + .code16; \ + .text; \ + .global _start; \ + _start:; \ + .short 0xaa55; \ + .byte 3; /* desired size in 512 units */ + +#define OPTION_ROM_END \ + _end: + +BOOT_ROM_START + +run_pvhboot: + + cli + cld + + mov %cs, %eax + shl $0x4, %eax + + /* set up a long jump descriptor that is PC relative */ + + /* move stack memory to %gs */ + mov %ss, %ecx + shl $0x4, %ecx + mov %esp, %ebx + add %ebx, %ecx + sub $0x20, %ecx + sub $0x30, %esp + shr $0x4, %ecx + mov %cx, %gs + + /* now push the indirect jump descriptor there */ + mov (prot_jump), %ebx + add %eax, %ebx + movl %ebx, %gs:GS_PROT_JUMP + mov $8, %bx + movw %bx, %gs:GS_PROT_JUMP + 4 + + /* fix the gdt descriptor to be PC relative */ + movw (gdt_desc), %bx + movw %bx, %gs:GS_GDT_DESC + movl (gdt_desc+2), %ebx + add %eax, %ebx + movl %ebx, %gs:GS_GDT_DESC + 2 + + /* initialize HVM memmap table using int 0x15(e820) */ + + /* ES = pvh_e820 struct */ + mov $pvh_e820, %eax + shr $4, %eax + mov %ax, %es + + /* start storing memmap table at %es:8 (pvh_e820.table) */ + mov $8,%edi + xor %ebx, %ebx + jmp memmap_loop + +memmap_loop_check: + /* pvh_e820 can contains up to 128 entries */ + cmp $128, %ebx + je memmap_done + +memmap_loop: + /* entry size (hvm_memmap_table_entry) & max buffer size (int15) */ + movl $24, %ecx + /* e820 */ + movl $0x0000e820, %eax + /* 'SMAP' magic */ + movl $0x534d4150, %edx + /* store counter value at %es:0 (pvh_e820.entries) */ + movl %ebx, %es:0 + + int $0x15 + /* error or last entry already done? */ + jb memmap_err + + /* %edi += entry size (hvm_memmap_table_entry) */ + add $24, %edi + + /* continuation value 0 means last entry */ + test %ebx, %ebx + jnz memmap_loop_check + + /* increase pvh_e820.entries to save the last entry */ + movl %es:0, %ebx + inc %ebx + +memmap_done: + movl %ebx, %es:0 + +memmap_err: + + /* load the GDT before going into protected mode */ +lgdt: + data32 lgdt %gs:GS_GDT_DESC + + /* get us to protected mode now */ + movl $1, %eax + movl %eax, %cr0 + + /* the LJMP sets CS for us and gets us to 32-bit */ +ljmp: + data32 ljmp *%gs:GS_PROT_JUMP + +prot_mode: +.code32 + + /* initialize all other segments */ + movl $0x10, %eax + movl %eax, %ss + movl %eax, %ds + movl %eax, %es + movl %eax, %fs + movl %eax, %gs + + jmp pvh_load_kernel + +/* Variables */ +.align 4, 0 +prot_jump: .long prot_mode + .short 8 + +.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 + + /* + * 0x18: code segment + * (base=0, limit=0x0ffff, type=16bit code exec/read/conf, DPL=0, 1b) + */ +.byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x9e, 0x00, 0x00 + + /* + * 0x20: data segment + * (base=0, limit=0x0ffff, type=16bit data read/write, DPL=0, 1b) + */ +.byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x92, 0x00, 0x00 + +gdt_desc: +.short (5 * 8) - 1 +.long gdt + +BOOT_ROM_END |