projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 64711f9a MF |
1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | // Copyright (C) 2018 Cadence Design Systems Inc. | |
| 3 | ||
| 4 | #include <linux/cpu.h> | |
| 5 | #include <linux/jump_label.h> | |
| 6 | #include <linux/kernel.h> | |
| 7 | #include <linux/memory.h> | |
| 8 | #include <linux/stop_machine.h> | |
| 9 | #include <linux/types.h> | |
| 10 | ||
| 11 | #include <asm/cacheflush.h> | |
| 12 | ||
| 64711f9a MF |
13 | #define J_OFFSET_MASK 0x0003ffff |
| 14 | #define J_SIGN_MASK (~(J_OFFSET_MASK >> 1)) | |
| 15 | ||
| 16 | #if defined(__XTENSA_EL__) | |
| 17 | #define J_INSN 0x6 | |
| 18 | #define NOP_INSN 0x0020f0 | |
| 19 | #elif defined(__XTENSA_EB__) | |
| 20 | #define J_INSN 0x60000000 | |
| 21 | #define NOP_INSN 0x0f020000 | |
| 22 | #else | |
| 23 | #error Unsupported endianness. | |
| 24 | #endif | |
| 25 | ||
| 26 | struct patch { | |
| 27 | atomic_t cpu_count; | |
| 28 | unsigned long addr; | |
| 29 | size_t sz; | |
| 30 | const void *data; | |
| 31 | }; | |
| 32 | ||
| 33 | static void local_patch_text(unsigned long addr, const void *data, size_t sz) | |
| 34 | { | |
| 35 | memcpy((void *)addr, data, sz); | |
| 36 | local_flush_icache_range(addr, addr + sz); | |
| 37 | } | |
| 38 | ||
| 39 | static int patch_text_stop_machine(void *data) | |
| 40 | { | |
| 41 | struct patch *patch = data; | |
| 42 | ||
| 43 | if (atomic_inc_return(&patch->cpu_count) == 1) { | |
| 44 | local_patch_text(patch->addr, patch->data, patch->sz); | |
| 45 | atomic_inc(&patch->cpu_count); | |
| 46 | } else { | |
| 47 | while (atomic_read(&patch->cpu_count) <= num_online_cpus()) | |
| 48 | cpu_relax(); | |
| 49 | __invalidate_icache_range(patch->addr, patch->sz); | |
| 50 | } | |
| 51 | return 0; | |
| 52 | } | |
| 53 | ||
| 54 | static void patch_text(unsigned long addr, const void *data, size_t sz) | |
| 55 | { | |
| 56 | if (IS_ENABLED(CONFIG_SMP)) { | |
| 57 | struct patch patch = { | |
| 58 | .cpu_count = ATOMIC_INIT(0), | |
| 59 | .addr = addr, | |
| 60 | .sz = sz, | |
| 61 | .data = data, | |
| 62 | }; | |
| 63 | stop_machine_cpuslocked(patch_text_stop_machine, | |
| 64 | &patch, NULL); | |
| 65 | } else { | |
| 66 | unsigned long flags; | |
| 67 | ||
| 68 | local_irq_save(flags); | |
| 69 | local_patch_text(addr, data, sz); | |
| 70 | local_irq_restore(flags); | |
| 71 | } | |
| 72 | } | |
| 73 | ||
| 74 | void arch_jump_label_transform(struct jump_entry *e, | |
| 75 | enum jump_label_type type) | |
| 76 | { | |
| 77 | u32 d = (jump_entry_target(e) - (jump_entry_code(e) + 4)); | |
| 78 | u32 insn; | |
| 79 | ||
| 80 | /* Jump only works within 128K of the J instruction. */ | |
| 81 | BUG_ON(!((d & J_SIGN_MASK) == 0 || | |
| 82 | (d & J_SIGN_MASK) == J_SIGN_MASK)); | |
| 83 | ||
| 84 | if (type == JUMP_LABEL_JMP) { | |
| 85 | #if defined(__XTENSA_EL__) | |
| 86 | insn = ((d & J_OFFSET_MASK) << 6) | J_INSN; | |
| 87 | #elif defined(__XTENSA_EB__) | |
| 88 | insn = ((d & J_OFFSET_MASK) << 8) | J_INSN; | |
| 89 | #endif | |
| 90 | } else { | |
| 91 | insn = NOP_INSN; | |
| 92 | } | |
| 93 | ||
| 94 | patch_text(jump_entry_code(e), &insn, JUMP_LABEL_NOP_SIZE); | |
| 95 | } |