From 654fc59fe4a7e1722dae2ab36fbbca212000f665 Mon Sep 17 00:00:00 2001 From: okuji Date: Sat, 16 Jul 2005 09:32:52 +0000 Subject: [PATCH] 2005-07-16 Yoshinori K. Okuji * kern/i386/pc/startup.S (grub_gate_a20): Rewritten for robustness. This routine now supports a BIOS call and System Control Port A to modify the gate A20. * include/grub/i386/pc/kernel.h (GRUB_KERNEL_MACHINE_RAW_SIZE): Increased to 0x440. --- ChangeLog | 9 +++ include/grub/i386/pc/kernel.h | 2 +- kern/i386/pc/startup.S | 141 ++++++++++++++++++++++++++-------- 3 files changed, 121 insertions(+), 31 deletions(-) diff --git a/ChangeLog b/ChangeLog index acc598b11..2ba78b61d 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,12 @@ +2005-07-16 Yoshinori K. Okuji + + * kern/i386/pc/startup.S (grub_gate_a20): Rewritten for + robustness. This routine now supports a BIOS call and System + Control Port A to modify the gate A20. + + * include/grub/i386/pc/kernel.h (GRUB_KERNEL_MACHINE_RAW_SIZE): + Increased to 0x440. + 2005-07-12 Hollis Blanchard * disk/powerpc/ieee1275/ofdisk.c (grub_ofdisk_open): dprintf the diff --git a/include/grub/i386/pc/kernel.h b/include/grub/i386/pc/kernel.h index 24d1cc9f8..0496e9645 100644 --- a/include/grub/i386/pc/kernel.h +++ b/include/grub/i386/pc/kernel.h @@ -39,7 +39,7 @@ #define GRUB_KERNEL_MACHINE_PREFIX 0x1c /* The size of the first region which won't be compressed. */ -#define GRUB_KERNEL_MACHINE_RAW_SIZE 0x400 +#define GRUB_KERNEL_MACHINE_RAW_SIZE 0x440 #ifndef ASM_FILE diff --git a/kern/i386/pc/startup.S b/kern/i386/pc/startup.S index b84320f97..3385e2ca2 100644 --- a/kern/i386/pc/startup.S +++ b/kern/i386/pc/startup.S @@ -125,7 +125,7 @@ codestart: /* reset disk system (%ah = 0) */ int $0x13 - + /* transition to protected mode */ DATA32 call real_to_prot @@ -134,7 +134,7 @@ codestart: incl %eax call EXT_C(grub_gate_a20) - + /* decompress the compressed part and put the result at 1MB */ movl $0x100000, %esi movl $(START_SYMBOL + GRUB_KERNEL_MACHINE_RAW_SIZE), %edi @@ -384,51 +384,132 @@ realcseg: */ FUNCTION(grub_gate_a20) - movl %eax, %ecx + movl %eax, %edx - call gloop1 +gate_a20_test_current_state: + /* first of all, test if already in a good state */ + call gate_a20_check_state + cmpb %al, %dl + jnz gate_a20_try_bios + ret + +gate_a20_try_bios: + /* second, try a BIOS call */ + pushl %ebp + call EXT_C(prot_to_real) + + .code16 + movw $0x2400, %ax + testb %dl, %dl + jz 1f + incw %ax +1: int $0x15 + + DATA32 call EXT_C(real_to_prot) + .code32 + + popl %ebp + call gate_a20_check_state + cmpb %al, %dl + jnz gate_a20_try_keyboard_controller + ret + +gate_a20_flush_keyboard_buffer: + inb $0x64 + andb $0x02, %al + jnz gate_a20_flush_keyboard_buffer +2: + inb $0x64 + andb $0x01, %al + jz 3f + inb $0x60 + jmp 2b +3: + ret + +gate_a20_try_keyboard_controller: + /* third, try the keyboard controller */ + call gate_a20_flush_keyboard_buffer movb $0xd1, %al outb $0x64 - -gloopint1: +4: inb $0x64 andb $0x02, %al - jnz gloopint1 + jnz 4b movb $0xdd, %al - testl %ecx, %ecx - jz gdoit - + testb %dl, %dl + jz 5f orb $0x02, %al -gdoit: - outb $0x60 - - call gloop1 +5: outb $0x60 + call gate_a20_flush_keyboard_buffer /* output a dummy command (USB keyboard hack) */ movb $0xff, %al outb $0x64 - call gloop1 + call gate_a20_flush_keyboard_buffer + call gate_a20_check_state + cmpb %al, %dl + jnz gate_a20_try_system_control_port_a ret -gloop1: - inb $0x64 - andb $0x02, %al - jnz gloop1 - -gloop2: - inb $0x64 - andb $0x01, %al - jz gloop2ret - inb $0x60 - jmp gloop2 - -gloop2ret: +gate_a20_try_system_control_port_a: + /* fourth, try the system control port A */ + inb $0x92 + andb $(~0x03), %al + testb %dl, %dl + jz 6f + orb $0x02, %al +6: outb $0x92 + + call gate_a20_check_state + cmpb %al, %dl + /* everything failed, so restart from the beginning */ + jnz gate_a20_try_bios ret - - + +gate_a20_check_state: + /* iterate the checking for a while */ + movl $100, %ecx +1: + call 3f + cmpb %al, %dl + jz 2f + loop 1b +2: + ret +3: + pushl %ebx + pushl %ecx + xorl %eax, %eax + /* compare the byte at 0x2000 with that at 0x102000 */ + movl $GRUB_BOOT_MACHINE_KERNEL_ADDR, %ebx + pushl %ebx + /* save the original byte in CL */ + movb (%ebx), %cl + /* store the value at 0x102000 in AL */ + addl $0x100000, %ebx + movb (%ebx), %al + /* try to set one less value at 0x2000 */ + popl %ebx + movb %al, %ch + decb %ch + movb %ch, (%ebx) + /* serialize */ + outb $0x80 + outb $0x80 + /* store the value at 0x2000 in CH */ + movb (%ebx), %ch + /* this result is 1 if A20 is on or 0 if it is off */ + subb %ch, %al + /* restore the original */ + movb %cl, (%ebx) + popl %ecx + popl %ebx + ret + #include "lzo1x.S"