| 1 | // SPDX-License-Identifier: GPL-2.0-only |
|---|---|
| 2 | /* |
| 3 | * Copyright (C) 2020 Emil Renner Berthing |
| 4 | * |
| 5 | * Based on arch/arm64/kernel/jump_label.c |
| 6 | */ |
| 7 | #include <linux/jump_label.h> |
| 8 | #include <linux/kernel.h> |
| 9 | #include <linux/memory.h> |
| 10 | #include <linux/mutex.h> |
| 11 | #include <asm/bug.h> |
| 12 | #include <asm/patch.h> |
| 13 | |
| 14 | #define RISCV_INSN_NOP 0x00000013U |
| 15 | #define RISCV_INSN_JAL 0x0000006fU |
| 16 | |
| 17 | void arch_jump_label_transform(struct jump_entry *entry, |
| 18 | enum jump_label_type type) |
| 19 | { |
| 20 | void *addr = (void *)jump_entry_code(entry); |
| 21 | u32 insn; |
| 22 | |
| 23 | if (type == JUMP_LABEL_JMP) { |
| 24 | long offset = jump_entry_target(entry) - jump_entry_code(entry); |
| 25 | |
| 26 | if (WARN_ON(offset & 1 || offset < -524288 || offset >= 524288)) |
| 27 | return; |
| 28 | |
| 29 | insn = RISCV_INSN_JAL | |
| 30 | (((u32)offset & GENMASK(19, 12)) << (12 - 12)) | |
| 31 | (((u32)offset & GENMASK(11, 11)) << (20 - 11)) | |
| 32 | (((u32)offset & GENMASK(10, 1)) << (21 - 1)) | |
| 33 | (((u32)offset & GENMASK(20, 20)) << (31 - 20)); |
| 34 | } else { |
| 35 | insn = RISCV_INSN_NOP; |
| 36 | } |
| 37 | |
| 38 | mutex_lock(&text_mutex); |
| 39 | patch_text_nosync(addr, &insn, sizeof(insn)); |
| 40 | mutex_unlock(lock: &text_mutex); |
| 41 | } |
| 42 |