1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | #include <linux/highmem.h> |
3 | #include <linux/ptrace.h> |
4 | #include <linux/sched.h> |
5 | #include <linux/uprobes.h> |
6 | #include <asm/cacheflush.h> |
7 | |
8 | #define UPROBE_TRAP_NR UINT_MAX |
9 | |
10 | int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, |
11 | struct mm_struct *mm, unsigned long addr) |
12 | { |
13 | int idx; |
14 | union loongarch_instruction insn; |
15 | |
16 | if (addr & 0x3) |
17 | return -EILSEQ; |
18 | |
19 | for (idx = ARRAY_SIZE(auprobe->insn) - 1; idx >= 0; idx--) { |
20 | insn.word = auprobe->insn[idx]; |
21 | if (insns_not_supported(insn)) |
22 | return -EINVAL; |
23 | } |
24 | |
25 | if (insns_need_simulation(insn)) { |
26 | auprobe->ixol[0] = larch_insn_gen_nop(); |
27 | auprobe->simulate = true; |
28 | } else { |
29 | auprobe->ixol[0] = auprobe->insn[0]; |
30 | auprobe->simulate = false; |
31 | } |
32 | |
33 | auprobe->ixol[1] = UPROBE_XOLBP_INSN; |
34 | |
35 | return 0; |
36 | } |
37 | |
38 | int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) |
39 | { |
40 | struct uprobe_task *utask = current->utask; |
41 | |
42 | utask->autask.saved_trap_nr = current->thread.trap_nr; |
43 | current->thread.trap_nr = UPROBE_TRAP_NR; |
44 | instruction_pointer_set(regs, val: utask->xol_vaddr); |
45 | user_enable_single_step(current); |
46 | |
47 | return 0; |
48 | } |
49 | |
50 | int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) |
51 | { |
52 | struct uprobe_task *utask = current->utask; |
53 | |
54 | WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR); |
55 | current->thread.trap_nr = utask->autask.saved_trap_nr; |
56 | |
57 | if (auprobe->simulate) |
58 | instruction_pointer_set(regs, val: auprobe->resume_era); |
59 | else |
60 | instruction_pointer_set(regs, val: utask->vaddr + LOONGARCH_INSN_SIZE); |
61 | |
62 | user_disable_single_step(current); |
63 | |
64 | return 0; |
65 | } |
66 | |
67 | void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) |
68 | { |
69 | struct uprobe_task *utask = current->utask; |
70 | |
71 | current->thread.trap_nr = utask->autask.saved_trap_nr; |
72 | instruction_pointer_set(regs, val: utask->vaddr); |
73 | user_disable_single_step(current); |
74 | } |
75 | |
76 | bool arch_uprobe_xol_was_trapped(struct task_struct *t) |
77 | { |
78 | if (t->thread.trap_nr != UPROBE_TRAP_NR) |
79 | return true; |
80 | |
81 | return false; |
82 | } |
83 | |
84 | bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs) |
85 | { |
86 | union loongarch_instruction insn; |
87 | |
88 | if (!auprobe->simulate) |
89 | return false; |
90 | |
91 | insn.word = auprobe->insn[0]; |
92 | arch_simulate_insn(insn, regs); |
93 | auprobe->resume_era = regs->csr_era; |
94 | |
95 | return true; |
96 | } |
97 | |
98 | unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, |
99 | struct pt_regs *regs) |
100 | { |
101 | unsigned long ra = regs->regs[1]; |
102 | |
103 | regs->regs[1] = trampoline_vaddr; |
104 | |
105 | return ra; |
106 | } |
107 | |
108 | bool arch_uretprobe_is_alive(struct return_instance *ret, |
109 | enum rp_check ctx, struct pt_regs *regs) |
110 | { |
111 | if (ctx == RP_CHECK_CHAIN_CALL) |
112 | return regs->regs[3] <= ret->stack; |
113 | else |
114 | return regs->regs[3] < ret->stack; |
115 | } |
116 | |
117 | int arch_uprobe_exception_notify(struct notifier_block *self, |
118 | unsigned long val, void *data) |
119 | { |
120 | return NOTIFY_DONE; |
121 | } |
122 | |
123 | bool uprobe_breakpoint_handler(struct pt_regs *regs) |
124 | { |
125 | if (uprobe_pre_sstep_notifier(regs)) |
126 | return true; |
127 | |
128 | return false; |
129 | } |
130 | |
131 | bool uprobe_singlestep_handler(struct pt_regs *regs) |
132 | { |
133 | if (uprobe_post_sstep_notifier(regs)) |
134 | return true; |
135 | |
136 | return false; |
137 | } |
138 | |
139 | unsigned long uprobe_get_swbp_addr(struct pt_regs *regs) |
140 | { |
141 | return instruction_pointer(regs); |
142 | } |
143 | |
144 | void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr, |
145 | void *src, unsigned long len) |
146 | { |
147 | void *kaddr = kmap_local_page(page); |
148 | void *dst = kaddr + (vaddr & ~PAGE_MASK); |
149 | |
150 | memcpy(dst, src, len); |
151 | flush_icache_range(start: (unsigned long)dst, end: (unsigned long)dst + len); |
152 | kunmap_local(kaddr); |
153 | } |
154 | |