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aaddd3ea ME |
1 | /* |
2 | * Copyright 2008 Michael Ellerman, IBM Corporation. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version | |
7 | * 2 of the License, or (at your option) any later version. | |
8 | */ | |
9 | ||
10 | #include <linux/kernel.h> | |
11 | #include <asm/code-patching.h> | |
12 | ||
13 | ||
e7a57273 | 14 | void patch_instruction(unsigned int *addr, unsigned int instr) |
aaddd3ea | 15 | { |
e7a57273 ME |
16 | *addr = instr; |
17 | asm ("dcbst 0, %0; sync; icbi 0,%0; sync; isync" : : "r" (addr)); | |
aaddd3ea ME |
18 | } |
19 | ||
e7a57273 ME |
20 | void patch_branch(unsigned int *addr, unsigned long target, int flags) |
21 | { | |
22 | patch_instruction(addr, create_branch(addr, target, flags)); | |
23 | } | |
24 | ||
25 | unsigned int create_branch(const unsigned int *addr, | |
26 | unsigned long target, int flags) | |
aaddd3ea ME |
27 | { |
28 | unsigned int instruction; | |
053a858e | 29 | long offset; |
aaddd3ea | 30 | |
053a858e | 31 | offset = target; |
aaddd3ea | 32 | if (! (flags & BRANCH_ABSOLUTE)) |
053a858e ME |
33 | offset = offset - (unsigned long)addr; |
34 | ||
35 | /* Check we can represent the target in the instruction format */ | |
36 | if (offset < -0x2000000 || offset > 0x1fffffc || offset & 0x3) | |
37 | return 0; | |
aaddd3ea ME |
38 | |
39 | /* Mask out the flags and target, so they don't step on each other. */ | |
053a858e | 40 | instruction = 0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC); |
aaddd3ea | 41 | |
e7a57273 | 42 | return instruction; |
aaddd3ea | 43 | } |