1 // SPDX-License-Identifier: GPL-2.0-only 2 3 #include <linux/highmem.h> 4 #include <linux/ptrace.h> 5 #include <linux/uprobes.h> 6 7 #include "decode-insn.h" 8 9 #define UPROBE_TRAP_NR UINT_MAX 10 11 bool is_swbp_insn(uprobe_opcode_t *insn) 12 { 13 #ifdef CONFIG_RISCV_ISA_C 14 return (*insn & 0xffff) == UPROBE_SWBP_INSN; 15 #else 16 return *insn == UPROBE_SWBP_INSN; 17 #endif 18 } 19 20 unsigned long uprobe_get_swbp_addr(struct pt_regs *regs) 21 { 22 return instruction_pointer(regs); 23 } 24 25 int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, 26 unsigned long addr) 27 { 28 probe_opcode_t opcode; 29 30 opcode = *(probe_opcode_t *)(&auprobe->insn[0]); 31 32 auprobe->insn_size = GET_INSN_LENGTH(opcode); 33 34 switch (riscv_probe_decode_insn(&opcode, &auprobe->api)) { 35 case INSN_REJECTED: 36 return -EINVAL; 37 38 case INSN_GOOD_NO_SLOT: 39 auprobe->simulate = true; 40 break; 41 42 case INSN_GOOD: 43 auprobe->simulate = false; 44 break; 45 46 default: 47 return -EINVAL; 48 } 49 50 return 0; 51 } 52 53 int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) 54 { 55 struct uprobe_task *utask = current->utask; 56 57 utask->autask.saved_cause = current->thread.bad_cause; 58 current->thread.bad_cause = UPROBE_TRAP_NR; 59 60 instruction_pointer_set(regs, utask->xol_vaddr); 61 62 return 0; 63 } 64 65 int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) 66 { 67 struct uprobe_task *utask = current->utask; 68 69 WARN_ON_ONCE(current->thread.bad_cause != UPROBE_TRAP_NR); 70 71 instruction_pointer_set(regs, utask->vaddr + auprobe->insn_size); 72 73 return 0; 74 } 75 76 bool arch_uprobe_xol_was_trapped(struct task_struct *t) 77 { 78 if (t->thread.bad_cause != 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 probe_opcode_t insn; 87 unsigned long addr; 88 89 if (!auprobe->simulate) 90 return false; 91 92 insn = *(probe_opcode_t *)(&auprobe->insn[0]); 93 addr = instruction_pointer(regs); 94 95 if (auprobe->api.handler) 96 auprobe->api.handler(insn, addr, regs); 97 98 return true; 99 } 100 101 void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) 102 { 103 struct uprobe_task *utask = current->utask; 104 105 /* 106 * Task has received a fatal signal, so reset back to probbed 107 * address. 108 */ 109 instruction_pointer_set(regs, utask->vaddr); 110 } 111 112 bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx, 113 struct pt_regs *regs) 114 { 115 if (ctx == RP_CHECK_CHAIN_CALL) 116 return regs->sp <= ret->stack; 117 else 118 return regs->sp < ret->stack; 119 } 120 121 unsigned long 122 arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, 123 struct pt_regs *regs) 124 { 125 unsigned long ra; 126 127 ra = regs->ra; 128 129 regs->ra = trampoline_vaddr; 130 131 return ra; 132 } 133 134 int arch_uprobe_exception_notify(struct notifier_block *self, 135 unsigned long val, void *data) 136 { 137 return NOTIFY_DONE; 138 } 139 140 bool uprobe_breakpoint_handler(struct pt_regs *regs) 141 { 142 if (uprobe_pre_sstep_notifier(regs)) 143 return true; 144 145 return false; 146 } 147 148 bool uprobe_single_step_handler(struct pt_regs *regs) 149 { 150 if (uprobe_post_sstep_notifier(regs)) 151 return true; 152 153 return false; 154 } 155 156 void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr, 157 void *src, unsigned long len) 158 { 159 /* Initialize the slot */ 160 void *kaddr = kmap_atomic(page); 161 void *dst = kaddr + (vaddr & ~PAGE_MASK); 162 163 memcpy(dst, src, len); 164 165 /* Add ebreak behind opcode to simulate singlestep */ 166 if (vaddr) { 167 dst += GET_INSN_LENGTH(*(probe_opcode_t *)src); 168 *(uprobe_opcode_t *)dst = __BUG_INSN_32; 169 } 170 171 kunmap_atomic(kaddr); 172 173 /* 174 * We probably need flush_icache_user_page() but it needs vma. 175 * This should work on most of architectures by default. If 176 * architecture needs to do something different it can define 177 * its own version of the function. 178 */ 179 flush_dcache_page(page); 180 } 181