| 1 | // SPDX-License-Identifier: GPL-2.0-only |
|---|---|
| 2 | |
| 3 | #include <linux/jump_label.h> |
| 4 | #include <linux/kernel.h> |
| 5 | #include <linux/memory.h> |
| 6 | #include <linux/mutex.h> |
| 7 | #include <linux/uaccess.h> |
| 8 | #include <asm/cacheflush.h> |
| 9 | |
| 10 | #define NOP32_HI 0xc400 |
| 11 | #define NOP32_LO 0x4820 |
| 12 | #define BSR_LINK 0xe000 |
| 13 | |
| 14 | void arch_jump_label_transform(struct jump_entry *entry, |
| 15 | enum jump_label_type type) |
| 16 | { |
| 17 | unsigned long addr = jump_entry_code(entry); |
| 18 | u16 insn[2]; |
| 19 | int ret = 0; |
| 20 | |
| 21 | if (type == JUMP_LABEL_JMP) { |
| 22 | long offset = jump_entry_target(entry) - jump_entry_code(entry); |
| 23 | |
| 24 | if (WARN_ON(offset & 1 || offset < -67108864 || offset >= 67108864)) |
| 25 | return; |
| 26 | |
| 27 | offset = offset >> 1; |
| 28 | |
| 29 | insn[0] = BSR_LINK | |
| 30 | ((uint16_t)((unsigned long) offset >> 16) & 0x3ff); |
| 31 | insn[1] = (uint16_t)((unsigned long) offset & 0xffff); |
| 32 | } else { |
| 33 | insn[0] = NOP32_HI; |
| 34 | insn[1] = NOP32_LO; |
| 35 | } |
| 36 | |
| 37 | ret = copy_to_kernel_nofault(dst: (void *)addr, src: insn, size: 4); |
| 38 | WARN_ON(ret); |
| 39 | |
| 40 | flush_icache_range(start: addr, end: addr + 4); |
| 41 | } |
| 42 | |
| 43 | void arch_jump_label_transform_static(struct jump_entry *entry, |
| 44 | enum jump_label_type type) |
| 45 | { |
| 46 | /* |
| 47 | * We use the same instructions in the arch_static_branch and |
| 48 | * arch_static_branch_jump inline functions, so there's no |
| 49 | * need to patch them up here. |
| 50 | * The core will call arch_jump_label_transform when those |
| 51 | * instructions need to be replaced. |
| 52 | */ |
| 53 | arch_jump_label_transform(entry, type); |
| 54 | } |
| 55 |