1 // SPDX-License-Identifier: GPL-2.0 2 3 #include <linux/kprobes.h> 4 5 int arch_check_ftrace_location(struct kprobe *p) 6 { 7 if (ftrace_location((unsigned long)p->addr)) 8 p->flags |= KPROBE_FLAG_FTRACE; 9 return 0; 10 } 11 12 /* Ftrace callback handler for kprobes -- called under preepmt disabed */ 13 void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, 14 struct ftrace_ops *ops, struct pt_regs *regs) 15 { 16 bool lr_saver = false; 17 struct kprobe *p; 18 struct kprobe_ctlblk *kcb; 19 20 /* Preempt is disabled by ftrace */ 21 p = get_kprobe((kprobe_opcode_t *)ip); 22 if (!p) { 23 p = get_kprobe((kprobe_opcode_t *)(ip - MCOUNT_INSN_SIZE)); 24 if (unlikely(!p) || kprobe_disabled(p)) 25 return; 26 lr_saver = true; 27 } 28 29 kcb = get_kprobe_ctlblk(); 30 if (kprobe_running()) { 31 kprobes_inc_nmissed_count(p); 32 } else { 33 unsigned long orig_ip = instruction_pointer(regs); 34 35 if (lr_saver) 36 ip -= MCOUNT_INSN_SIZE; 37 instruction_pointer_set(regs, ip); 38 __this_cpu_write(current_kprobe, p); 39 kcb->kprobe_status = KPROBE_HIT_ACTIVE; 40 if (!p->pre_handler || !p->pre_handler(p, regs)) { 41 /* 42 * Emulate singlestep (and also recover regs->pc) 43 * as if there is a nop 44 */ 45 instruction_pointer_set(regs, 46 (unsigned long)p->addr + MCOUNT_INSN_SIZE); 47 if (unlikely(p->post_handler)) { 48 kcb->kprobe_status = KPROBE_HIT_SSDONE; 49 p->post_handler(p, regs, 0); 50 } 51 instruction_pointer_set(regs, orig_ip); 52 } 53 /* 54 * If pre_handler returns !0, it changes regs->pc. We have to 55 * skip emulating post_handler. 56 */ 57 __this_cpu_write(current_kprobe, NULL); 58 } 59 } 60 NOKPROBE_SYMBOL(kprobe_ftrace_handler); 61 62 int arch_prepare_kprobe_ftrace(struct kprobe *p) 63 { 64 p->ainsn.api.insn = NULL; 65 return 0; 66 } 67