64 lines
1.4 KiB
C
64 lines
1.4 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/bug.h>
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#include <linux/kernel.h>
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#include <asm/opcodes.h>
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static unsigned long
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__arm_gen_branch_thumb2(unsigned long pc, unsigned long addr, bool link)
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{
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unsigned long s, j1, j2, i1, i2, imm10, imm11;
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unsigned long first, second;
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long offset;
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offset = (long)addr - (long)(pc + 4);
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if (offset < -16777216 || offset > 16777214) {
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WARN_ON_ONCE(1);
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return 0;
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}
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s = (offset >> 24) & 0x1;
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i1 = (offset >> 23) & 0x1;
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i2 = (offset >> 22) & 0x1;
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imm10 = (offset >> 12) & 0x3ff;
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imm11 = (offset >> 1) & 0x7ff;
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j1 = (!i1) ^ s;
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j2 = (!i2) ^ s;
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first = 0xf000 | (s << 10) | imm10;
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second = 0x9000 | (j1 << 13) | (j2 << 11) | imm11;
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if (link)
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second |= 1 << 14;
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return __opcode_thumb32_compose(first, second);
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}
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static unsigned long
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__arm_gen_branch_arm(unsigned long pc, unsigned long addr, bool link)
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{
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unsigned long opcode = 0xea000000;
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long offset;
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if (link)
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opcode |= 1 << 24;
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offset = (long)addr - (long)(pc + 8);
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if (unlikely(offset < -33554432 || offset > 33554428)) {
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WARN_ON_ONCE(1);
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return 0;
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}
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offset = (offset >> 2) & 0x00ffffff;
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return opcode | offset;
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}
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unsigned long
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__arm_gen_branch(unsigned long pc, unsigned long addr, bool link)
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{
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if (IS_ENABLED(CONFIG_THUMB2_KERNEL))
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return __arm_gen_branch_thumb2(pc, addr, link);
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else
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return __arm_gen_branch_arm(pc, addr, link);
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}
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