projects / mirror_ubuntu-bionic-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 7a734e7d PA |
1 | /* ----------------------------------------------------------------------- |
| 2 | * | |
| 6f34152f | 3 | * Copyright 2009-2014 Intel Corporation; author H. Peter Anvin |
| 7a734e7d PA |
4 | * |
| 5 | * This file is part of the Linux kernel, and is made available under | |
| 6 | * the terms of the GNU General Public License version 2 or (at your | |
| 7 | * option) any later version; incorporated herein by reference. | |
| 8 | * | |
| 9 | * ----------------------------------------------------------------------- */ | |
| 10 | ||
| 11 | /* | |
| 12 | * "Glove box" for BIOS calls. Avoids the constant problems with BIOSes | |
| cf9972a9 | 13 | * touching registers they shouldn't be. |
| 7a734e7d PA |
14 | */ |
| 15 | ||
| e24df921 | 16 | .code16 |
| 6f34152f | 17 | .section ".inittext","ax" |
| 7a734e7d PA |
18 | .globl intcall |
| 19 | .type intcall, @function | |
| 20 | intcall: | |
| 21 | /* Self-modify the INT instruction. Ugly, but works. */ | |
| 22 | cmpb %al, 3f | |
| 23 | je 1f | |
| 24 | movb %al, 3f | |
| 25 | jmp 1f /* Synchronize pipeline */ | |
| 26 | 1: | |
| 27 | /* Save state */ | |
| 28 | pushfl | |
| 29 | pushw %fs | |
| 30 | pushw %gs | |
| 31 | pushal | |
| 32 | ||
| 33 | /* Copy input state to stack frame */ | |
| 34 | subw $44, %sp | |
| 35 | movw %dx, %si | |
| 36 | movw %sp, %di | |
| 37 | movw $11, %cx | |
| 38 | rep; movsd | |
| 39 | ||
| 40 | /* Pop full state from the stack */ | |
| 41 | popal | |
| 42 | popw %gs | |
| 43 | popw %fs | |
| 44 | popw %es | |
| 45 | popw %ds | |
| 46 | popfl | |
| 47 | ||
| 48 | /* Actual INT */ | |
| 49 | .byte 0xcd /* INT opcode */ | |
| 50 | 3: .byte 0 | |
| 51 | ||
| 52 | /* Push full state to the stack */ | |
| 53 | pushfl | |
| 54 | pushw %ds | |
| 55 | pushw %es | |
| 56 | pushw %fs | |
| 57 | pushw %gs | |
| 58 | pushal | |
| 59 | ||
| 60 | /* Re-establish C environment invariants */ | |
| 61 | cld | |
| 62 | movzwl %sp, %esp | |
| 63 | movw %cs, %ax | |
| 64 | movw %ax, %ds | |
| 65 | movw %ax, %es | |
| 66 | ||
| 67 | /* Copy output state from stack frame */ | |
| 68 | movw 68(%esp), %di /* Original %cx == 3rd argument */ | |
| 69 | andw %di, %di | |
| 70 | jz 4f | |
| 71 | movw %sp, %si | |
| 72 | movw $11, %cx | |
| 73 | rep; movsd | |
| 74 | 4: addw $44, %sp | |
| 75 | ||
| 76 | /* Restore state and return */ | |
| 77 | popal | |
| 78 | popw %gs | |
| 79 | popw %fs | |
| 80 | popfl | |
| 81 | retl | |
| 82 | .size intcall, .-intcall |