55 lines
1.3 KiB
C
55 lines
1.3 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/jump_label.h>
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#include <linux/kernel.h>
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#include <linux/memory.h>
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#include <linux/mutex.h>
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#include <linux/uaccess.h>
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#include <asm/cacheflush.h>
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#define NOP32_HI 0xc400
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#define NOP32_LO 0x4820
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#define BSR_LINK 0xe000
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void arch_jump_label_transform(struct jump_entry *entry,
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enum jump_label_type type)
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{
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unsigned long addr = jump_entry_code(entry);
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u16 insn[2];
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int ret = 0;
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if (type == JUMP_LABEL_JMP) {
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long offset = jump_entry_target(entry) - jump_entry_code(entry);
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if (WARN_ON(offset & 1 || offset < -67108864 || offset >= 67108864))
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return;
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offset = offset >> 1;
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insn[0] = BSR_LINK |
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((uint16_t)((unsigned long) offset >> 16) & 0x3ff);
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insn[1] = (uint16_t)((unsigned long) offset & 0xffff);
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} else {
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insn[0] = NOP32_HI;
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insn[1] = NOP32_LO;
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}
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ret = copy_to_kernel_nofault((void *)addr, insn, 4);
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WARN_ON(ret);
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flush_icache_range(addr, addr + 4);
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}
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void arch_jump_label_transform_static(struct jump_entry *entry,
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enum jump_label_type type)
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{
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/*
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* We use the same instructions in the arch_static_branch and
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* arch_static_branch_jump inline functions, so there's no
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* need to patch them up here.
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* The core will call arch_jump_label_transform when those
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* instructions need to be replaced.
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*/
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arch_jump_label_transform(entry, type);
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}
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