| .. | .. |
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| 1 | | -/* SPDX-License-Identifier: GPL-2.0 */ |
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| 1 | +// SPDX-License-Identifier: GPL-2.0 |
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| 2 | 2 | /* |
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| 3 | 3 | * Copyright (C) 2013 Linaro Limited |
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| 4 | 4 | * Author: AKASHI Takahiro <takahiro.akashi@linaro.org> |
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| .. | .. |
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| 7 | 7 | |
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| 8 | 8 | #include <linux/ftrace.h> |
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| 9 | 9 | #include <linux/uaccess.h> |
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| 10 | +#include <linux/memory.h> |
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| 10 | 11 | #include <asm/cacheflush.h> |
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| 12 | +#include <asm/patch.h> |
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| 11 | 13 | |
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| 12 | 14 | #ifdef CONFIG_DYNAMIC_FTRACE |
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| 15 | +int ftrace_arch_code_modify_prepare(void) __acquires(&text_mutex) |
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| 16 | +{ |
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| 17 | + mutex_lock(&text_mutex); |
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| 18 | + |
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| 19 | + /* |
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| 20 | + * The code sequences we use for ftrace can't be patched while the |
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| 21 | + * kernel is running, so we need to use stop_machine() to modify them |
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| 22 | + * for now. This doesn't play nice with text_mutex, we use this flag |
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| 23 | + * to elide the check. |
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| 24 | + */ |
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| 25 | + riscv_patch_in_stop_machine = true; |
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| 26 | + |
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| 27 | + return 0; |
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| 28 | +} |
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| 29 | + |
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| 30 | +int ftrace_arch_code_modify_post_process(void) __releases(&text_mutex) |
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| 31 | +{ |
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| 32 | + riscv_patch_in_stop_machine = false; |
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| 33 | + mutex_unlock(&text_mutex); |
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| 34 | + return 0; |
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| 35 | +} |
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| 36 | + |
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| 13 | 37 | static int ftrace_check_current_call(unsigned long hook_pos, |
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| 14 | 38 | unsigned int *expected) |
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| 15 | 39 | { |
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| .. | .. |
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| 24 | 48 | * Read the text we want to modify; |
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| 25 | 49 | * return must be -EFAULT on read error |
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| 26 | 50 | */ |
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| 27 | | - if (probe_kernel_read(replaced, (void *)hook_pos, MCOUNT_INSN_SIZE)) |
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| 51 | + if (copy_from_kernel_nofault(replaced, (void *)hook_pos, |
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| 52 | + MCOUNT_INSN_SIZE)) |
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| 28 | 53 | return -EFAULT; |
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| 29 | 54 | |
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| 30 | 55 | /* |
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| .. | .. |
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| 32 | 57 | * return must be -EINVAL on failed comparison |
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| 33 | 58 | */ |
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| 34 | 59 | if (memcmp(expected, replaced, sizeof(replaced))) { |
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| 35 | | - pr_err("%p: expected (%08x %08x) but get (%08x %08x)", |
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| 60 | + pr_err("%p: expected (%08x %08x) but got (%08x %08x)\n", |
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| 36 | 61 | (void *)hook_pos, expected[0], expected[1], replaced[0], |
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| 37 | 62 | replaced[1]); |
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| 38 | 63 | return -EINVAL; |
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| .. | .. |
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| 46 | 71 | { |
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| 47 | 72 | unsigned int call[2]; |
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| 48 | 73 | unsigned int nops[2] = {NOP4, NOP4}; |
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| 49 | | - int ret = 0; |
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| 50 | 74 | |
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| 51 | 75 | make_call(hook_pos, target, call); |
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| 52 | 76 | |
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| 53 | | - /* replace the auipc-jalr pair at once */ |
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| 54 | | - ret = probe_kernel_write((void *)hook_pos, enable ? call : nops, |
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| 55 | | - MCOUNT_INSN_SIZE); |
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| 56 | | - /* return must be -EPERM on write error */ |
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| 57 | | - if (ret) |
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| 77 | + /* Replace the auipc-jalr pair at once. Return -EPERM on write error. */ |
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| 78 | + if (patch_text_nosync |
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| 79 | + ((void *)hook_pos, enable ? call : nops, MCOUNT_INSN_SIZE)) |
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| 58 | 80 | return -EPERM; |
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| 59 | | - |
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| 60 | | - smp_mb(); |
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| 61 | | - flush_icache_range((void *)hook_pos, (void *)hook_pos + MCOUNT_INSN_SIZE); |
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| 62 | 81 | |
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| 63 | 82 | return 0; |
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| 64 | 83 | } |
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| .. | .. |
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| 100 | 119 | { |
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| 101 | 120 | int out; |
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| 102 | 121 | |
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| 103 | | - ftrace_arch_code_modify_prepare(); |
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| 122 | + mutex_lock(&text_mutex); |
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| 104 | 123 | out = ftrace_make_nop(mod, rec, MCOUNT_ADDR); |
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| 105 | | - ftrace_arch_code_modify_post_process(); |
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| 124 | + mutex_unlock(&text_mutex); |
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| 106 | 125 | |
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| 107 | 126 | return out; |
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| 108 | 127 | } |
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