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