| 1 | |
| 2 | #include <linux/bug.h>
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| 3 | #include <linux/kernel.h>
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| 4 | #include <asm/opcodes.h>
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| 5 |
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| 6 | static unsigned long __arm_gen_branch_thumb2(unsigned long pc,
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| 7 | unsigned long addr, bool link,
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| 8 | bool warn)
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| 9 | {
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| 10 | unsigned long s, j1, j2, i1, i2, imm10, imm11;
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| 11 | unsigned long first, second;
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| 12 | long offset;
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| 13 |
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| 14 | offset = (long)addr - (long)(pc + 4);
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| 15 | if (offset < -16777216 || offset > 16777214) {
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| 16 | WARN_ON_ONCE(warn);
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| 17 | return 0;
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| 18 | }
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| 19 |
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| 20 | s = (offset >> 24) & 0x1;
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| 21 | i1 = (offset >> 23) & 0x1;
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| 22 | i2 = (offset >> 22) & 0x1;
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| 23 | imm10 = (offset >> 12) & 0x3ff;
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| 24 | imm11 = (offset >> 1) & 0x7ff;
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| 25 |
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| 26 | j1 = (!i1) ^ s;
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| 27 | j2 = (!i2) ^ s;
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| 28 |
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| 29 | first = 0xf000 | (s << 10) | imm10;
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| 30 | second = 0x9000 | (j1 << 13) | (j2 << 11) | imm11;
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| 31 | if (link)
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| 32 | second |= 1 << 14;
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| 33 |
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| 34 | return __opcode_thumb32_compose(first, second);
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| 35 | }
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| 36 |
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| 37 | static unsigned long __arm_gen_branch_arm(unsigned long pc, unsigned long addr,
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| 38 | bool link, bool warn)
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| 39 | {
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| 40 | unsigned long opcode = 0xea000000;
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| 41 | long offset;
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| 42 |
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| 43 | if (link)
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| 44 | opcode |= 1 << 24;
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| 45 |
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| 46 | offset = (long)addr - (long)(pc + 8);
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| 47 | if (unlikely(offset < -33554432 || offset > 33554428)) {
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| 48 | WARN_ON_ONCE(warn);
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| 49 | return 0;
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| 50 | }
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| 51 |
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| 52 | offset = (offset >> 2) & 0x00ffffff;
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| 53 |
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| 54 | return opcode | offset;
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| 55 | }
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| 56 |
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| 57 | unsigned long
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| 58 | __arm_gen_branch(unsigned long pc, unsigned long addr, bool link, bool warn)
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| 59 | {
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| 60 | if (IS_ENABLED(CONFIG_THUMB2_KERNEL))
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| 61 | return __arm_gen_branch_thumb2(pc, addr, link, warn);
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| 62 | else
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| 63 | return __arm_gen_branch_arm(pc, addr, link, warn);
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| 64 | }
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