| 1 | |
| 2 |
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| 3 | #include <linux/jump_label.h>
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| 4 | #include <linux/kernel.h>
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| 5 | #include <linux/memory.h>
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| 6 | #include <linux/mutex.h>
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| 7 | #include <linux/uaccess.h>
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| 8 | #include <asm/cacheflush.h>
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| 9 |
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| 10 | #define NOP32_HI 0xc400
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| 11 | #define NOP32_LO 0x4820
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| 12 | #define BSR_LINK 0xe000
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| 13 |
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| 14 | void arch_jump_label_transform(struct jump_entry *entry,
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| 15 | enum jump_label_type type)
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| 16 | {
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| 17 | unsigned long addr = jump_entry_code(entry);
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| 18 | u16 insn[2];
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| 19 | int ret = 0;
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| 20 |
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| 21 | if (type == JUMP_LABEL_JMP) {
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| 22 | long offset = jump_entry_target(entry) - jump_entry_code(entry);
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| 23 |
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| 24 | if (WARN_ON(offset & 1 || offset < -67108864 || offset >= 67108864))
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| 25 | return;
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| 26 |
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| 27 | offset = offset >> 1;
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| 28 |
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| 29 | insn[0] = BSR_LINK |
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| 30 | ((uint16_t)((unsigned long) offset >> 16) & 0x3ff);
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| 31 | insn[1] = (uint16_t)((unsigned long) offset & 0xffff);
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| 32 | } else {
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| 33 | insn[0] = NOP32_HI;
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| 34 | insn[1] = NOP32_LO;
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| 35 | }
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| 36 |
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| 37 | ret = copy_to_kernel_nofault((void *)addr, insn, 4);
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| 38 | WARN_ON(ret);
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| 39 |
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| 40 | flush_icache_range(addr, addr + 4);
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| 41 | }
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| 42 |
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| 43 | void arch_jump_label_transform_static(struct jump_entry *entry,
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| 44 | enum jump_label_type type)
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| 45 | {
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| 46 | |
| 47 | * We use the same instructions in the arch_static_branch and
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| 48 | * arch_static_branch_jump inline functions, so there's no
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| 49 | * need to patch them up here.
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| 50 | * The core will call arch_jump_label_transform when those
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| 51 | * instructions need to be replaced.
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| 52 |
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| 53 | arch_jump_label_transform(entry, type);
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| 54 | }
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