diff options
author | David S. Miller <davem@davemloft.net> | 2009-06-15 03:02:23 -0700 |
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committer | David S. Miller <davem@davemloft.net> | 2009-06-15 03:02:23 -0700 |
commit | 9cbc1cb8cd46ce1f7645b9de249b2ce8460129bb (patch) | |
tree | 8d104ec2a459346b99413b0b77421ca7b9936c1a /arch/x86/boot/bioscall.S | |
parent | ca44d6e60f9de26281fda203f58b570e1748c015 (diff) | |
parent | 45e3e1935e2857c54783291107d33323b3ef33c8 (diff) |
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:
Documentation/feature-removal-schedule.txt
drivers/scsi/fcoe/fcoe.c
net/core/drop_monitor.c
net/core/net-traces.c
Diffstat (limited to 'arch/x86/boot/bioscall.S')
-rw-r--r-- | arch/x86/boot/bioscall.S | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/arch/x86/boot/bioscall.S b/arch/x86/boot/bioscall.S new file mode 100644 index 00000000000..507793739ea --- /dev/null +++ b/arch/x86/boot/bioscall.S @@ -0,0 +1,82 @@ +/* ----------------------------------------------------------------------- + * + * Copyright 2009 Intel Corporation; author H. Peter Anvin + * + * This file is part of the Linux kernel, and is made available under + * the terms of the GNU General Public License version 2 or (at your + * option) any later version; incorporated herein by reference. + * + * ----------------------------------------------------------------------- */ + +/* + * "Glove box" for BIOS calls. Avoids the constant problems with BIOSes + * touching registers they shouldn't be. + */ + + .code16 + .text + .globl intcall + .type intcall, @function +intcall: + /* Self-modify the INT instruction. Ugly, but works. */ + cmpb %al, 3f + je 1f + movb %al, 3f + jmp 1f /* Synchronize pipeline */ +1: + /* Save state */ + pushfl + pushw %fs + pushw %gs + pushal + + /* Copy input state to stack frame */ + subw $44, %sp + movw %dx, %si + movw %sp, %di + movw $11, %cx + rep; movsd + + /* Pop full state from the stack */ + popal + popw %gs + popw %fs + popw %es + popw %ds + popfl + + /* Actual INT */ + .byte 0xcd /* INT opcode */ +3: .byte 0 + + /* Push full state to the stack */ + pushfl + pushw %ds + pushw %es + pushw %fs + pushw %gs + pushal + + /* Re-establish C environment invariants */ + cld + movzwl %sp, %esp + movw %cs, %ax + movw %ax, %ds + movw %ax, %es + + /* Copy output state from stack frame */ + movw 68(%esp), %di /* Original %cx == 3rd argument */ + andw %di, %di + jz 4f + movw %sp, %si + movw $11, %cx + rep; movsd +4: addw $44, %sp + + /* Restore state and return */ + popal + popw %gs + popw %fs + popfl + retl + .size intcall, .-intcall |