Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6) #include <linux/types.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7) #include <linux/kprobes.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include <linux/kdebug.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <linux/sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/uaccess.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <asm/cacheflush.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <asm/current.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <asm/disasm.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #define MIN_STACK_SIZE(addr)	min((unsigned long)MAX_STACK_SIZE, \
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) 		(unsigned long)current_thread_info() + THREAD_SIZE - (addr))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) int __kprobes arch_prepare_kprobe(struct kprobe *p)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) 	/* Attempt to probe at unaligned address */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) 	if ((unsigned long)p->addr & 0x01)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) 	/* Address should not be in exception handling code */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 	p->ainsn.is_short = is_short_instr((unsigned long)p->addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 	p->opcode = *p->addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) void __kprobes arch_arm_kprobe(struct kprobe *p)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 	*p->addr = UNIMP_S_INSTRUCTION;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 	flush_icache_range((unsigned long)p->addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 			   (unsigned long)p->addr + sizeof(kprobe_opcode_t));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) void __kprobes arch_disarm_kprobe(struct kprobe *p)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 	*p->addr = p->opcode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 	flush_icache_range((unsigned long)p->addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 			   (unsigned long)p->addr + sizeof(kprobe_opcode_t));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) void __kprobes arch_remove_kprobe(struct kprobe *p)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 	arch_disarm_kprobe(p);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 	/* Can we remove the kprobe in the middle of kprobe handling? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 	if (p->ainsn.t1_addr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 		*(p->ainsn.t1_addr) = p->ainsn.t1_opcode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 		flush_icache_range((unsigned long)p->ainsn.t1_addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 				   (unsigned long)p->ainsn.t1_addr +
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 				   sizeof(kprobe_opcode_t));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 		p->ainsn.t1_addr = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 	if (p->ainsn.t2_addr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 		*(p->ainsn.t2_addr) = p->ainsn.t2_opcode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 		flush_icache_range((unsigned long)p->ainsn.t2_addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 				   (unsigned long)p->ainsn.t2_addr +
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 				   sizeof(kprobe_opcode_t));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 		p->ainsn.t2_addr = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 	kcb->prev_kprobe.kp = kprobe_running();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 	kcb->prev_kprobe.status = kcb->kprobe_status;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	__this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 	kcb->kprobe_status = kcb->prev_kprobe.status;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) static inline void __kprobes set_current_kprobe(struct kprobe *p)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 	__this_cpu_write(current_kprobe, p);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) static void __kprobes resume_execution(struct kprobe *p, unsigned long addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 				       struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 	/* Remove the trap instructions inserted for single step and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 	 * restore the original instructions
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 	if (p->ainsn.t1_addr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 		*(p->ainsn.t1_addr) = p->ainsn.t1_opcode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 		flush_icache_range((unsigned long)p->ainsn.t1_addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 				   (unsigned long)p->ainsn.t1_addr +
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 				   sizeof(kprobe_opcode_t));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 		p->ainsn.t1_addr = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 	if (p->ainsn.t2_addr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 		*(p->ainsn.t2_addr) = p->ainsn.t2_opcode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 		flush_icache_range((unsigned long)p->ainsn.t2_addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 				   (unsigned long)p->ainsn.t2_addr +
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 				   sizeof(kprobe_opcode_t));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 		p->ainsn.t2_addr = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) static void __kprobes setup_singlestep(struct kprobe *p, struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 	unsigned long next_pc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 	unsigned long tgt_if_br = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 	int is_branch;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 	unsigned long bta;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 	/* Copy the opcode back to the kprobe location and execute the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 	 * instruction. Because of this we will not be able to get into the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 	 * same kprobe until this kprobe is done
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 	*(p->addr) = p->opcode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	flush_icache_range((unsigned long)p->addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 			   (unsigned long)p->addr + sizeof(kprobe_opcode_t));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	/* Now we insert the trap at the next location after this instruction to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 	 * single step. If it is a branch we insert the trap at possible branch
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 	 * targets
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 	bta = regs->bta;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 	if (regs->status32 & 0x40) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 		/* We are in a delay slot with the branch taken */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 		next_pc = bta & ~0x01;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 		if (!p->ainsn.is_short) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 			if (bta & 0x01)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 				regs->blink += 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 			else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 				/* Branch not taken */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 				next_pc += 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 				/* next pc is taken from bta after executing the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 				 * delay slot instruction
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 				 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 				regs->bta += 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 		is_branch = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 	} else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 		is_branch =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 		    disasm_next_pc((unsigned long)p->addr, regs,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 			(struct callee_regs *) current->thread.callee_reg,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 			&next_pc, &tgt_if_br);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	p->ainsn.t1_addr = (kprobe_opcode_t *) next_pc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 	p->ainsn.t1_opcode = *(p->ainsn.t1_addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	*(p->ainsn.t1_addr) = TRAP_S_2_INSTRUCTION;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 	flush_icache_range((unsigned long)p->ainsn.t1_addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 			   (unsigned long)p->ainsn.t1_addr +
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 			   sizeof(kprobe_opcode_t));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 	if (is_branch) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 		p->ainsn.t2_addr = (kprobe_opcode_t *) tgt_if_br;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 		p->ainsn.t2_opcode = *(p->ainsn.t2_addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 		*(p->ainsn.t2_addr) = TRAP_S_2_INSTRUCTION;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 		flush_icache_range((unsigned long)p->ainsn.t2_addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 				   (unsigned long)p->ainsn.t2_addr +
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 				   sizeof(kprobe_opcode_t));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) int __kprobes arc_kprobe_handler(unsigned long addr, struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 	struct kprobe *p;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 	struct kprobe_ctlblk *kcb;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 	preempt_disable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 	kcb = get_kprobe_ctlblk();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 	p = get_kprobe((unsigned long *)addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 	if (p) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 		 * We have reentered the kprobe_handler, since another kprobe
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 		 * was hit while within the handler, we save the original
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 		 * kprobes and single step on the instruction of the new probe
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 		 * without calling any user handlers to avoid recursive
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 		 * kprobes.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 		if (kprobe_running()) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 			save_previous_kprobe(kcb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 			set_current_kprobe(p);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 			kprobes_inc_nmissed_count(p);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 			setup_singlestep(p, regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 			kcb->kprobe_status = KPROBE_REENTER;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 			return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 		set_current_kprobe(p);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 		kcb->kprobe_status = KPROBE_HIT_ACTIVE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 		/* If we have no pre-handler or it returned 0, we continue with
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 		 * normal processing. If we have a pre-handler and it returned
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 		 * non-zero - which means user handler setup registers to exit
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 		 * to another instruction, we must skip the single stepping.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 		if (!p->pre_handler || !p->pre_handler(p, regs)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 			setup_singlestep(p, regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 			kcb->kprobe_status = KPROBE_HIT_SS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 		} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 			reset_current_kprobe();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 			preempt_enable_no_resched();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 		return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 	/* no_kprobe: */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 	preempt_enable_no_resched();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) static int __kprobes arc_post_kprobe_handler(unsigned long addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 					 struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 	struct kprobe *cur = kprobe_running();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 	if (!cur)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 	resume_execution(cur, addr, regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 	/* Rearm the kprobe */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 	arch_arm_kprobe(cur);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 	 * When we return from trap instruction we go to the next instruction
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 	 * We restored the actual instruction in resume_exectuiont and we to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 	 * return to the same address and execute it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 	regs->ret = addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 	if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 		kcb->kprobe_status = KPROBE_HIT_SSDONE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 		cur->post_handler(cur, regs, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 	if (kcb->kprobe_status == KPROBE_REENTER) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 		restore_previous_kprobe(kcb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 	reset_current_kprobe();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 	preempt_enable_no_resched();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 	return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283)  * Fault can be for the instruction being single stepped or for the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284)  * pre/post handlers in the module.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285)  * This is applicable for applications like user probes, where we have the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286)  * probe in user space and the handlers in the kernel
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned long trapnr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) 	struct kprobe *cur = kprobe_running();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 	switch (kcb->kprobe_status) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 	case KPROBE_HIT_SS:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 	case KPROBE_REENTER:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 		 * We are here because the instruction being single stepped
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 		 * caused the fault. We reset the current kprobe and allow the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) 		 * exception handler as if it is regular exception. In our
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) 		 * case it doesn't matter because the system will be halted
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) 		resume_execution(cur, (unsigned long)cur->addr, regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) 		if (kcb->kprobe_status == KPROBE_REENTER)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 			restore_previous_kprobe(kcb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 		else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 			reset_current_kprobe();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) 		preempt_enable_no_resched();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 	case KPROBE_HIT_ACTIVE:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) 	case KPROBE_HIT_SSDONE:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 		 * We are here because the instructions in the pre/post handler
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 		 * caused the fault.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) 		/* We increment the nmissed count for accounting,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) 		 * we can also use npre/npostfault count for accounting
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) 		 * these specific fault cases.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) 		kprobes_inc_nmissed_count(cur);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) 		 * We come here because instructions in the pre/post
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) 		 * handler caused the page_fault, this could happen
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) 		 * if handler tries to access user space by
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) 		 * copy_from_user(), get_user() etc. Let the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) 		 * user-specified handler try to fix it first.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) 		if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) 			return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) 		 * In case the user-specified fault handler returned zero,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) 		 * try to fix up.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) 		if (fixup_exception(regs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) 			return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) 		 * fixup_exception() could not handle it,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) 		 * Let do_page_fault() fix it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) 	default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) 				       unsigned long val, void *data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) 	struct die_args *args = data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) 	unsigned long addr = args->err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) 	int ret = NOTIFY_DONE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362) 	switch (val) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363) 	case DIE_IERR:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) 		if (arc_kprobe_handler(addr, args->regs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) 			return NOTIFY_STOP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368) 	case DIE_TRAP:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) 		if (arc_post_kprobe_handler(addr, args->regs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) 			return NOTIFY_STOP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) 	default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) static void __used kretprobe_trampoline_holder(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) 	__asm__ __volatile__(".global kretprobe_trampoline\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383) 			     "kretprobe_trampoline:\n" "nop\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386) void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) 				      struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) 	ri->ret_addr = (kprobe_opcode_t *) regs->blink;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) 	ri->fp = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 393) 	/* Replace the return addr with trampoline addr */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 394) 	regs->blink = (unsigned long)&kretprobe_trampoline;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 395) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 396) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 397) static int __kprobes trampoline_probe_handler(struct kprobe *p,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 398) 					      struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 399) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 400) 	regs->ret = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 401) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 402) 	/* By returning a non zero value, we are telling the kprobe handler
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 403) 	 * that we don't want the post_handler to run
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 404) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 405) 	return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 406) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 407) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 408) static struct kprobe trampoline_p = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 409) 	.addr = (kprobe_opcode_t *) &kretprobe_trampoline,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 410) 	.pre_handler = trampoline_probe_handler
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 411) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 412) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 413) int __init arch_init_kprobes(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 414) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 415) 	/* Registering the trampoline code for the kret probe */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 416) 	return register_kprobe(&trampoline_p);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 417) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 418) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 419) int __kprobes arch_trampoline_kprobe(struct kprobe *p)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 420) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 421) 	if (p->addr == (kprobe_opcode_t *) &kretprobe_trampoline)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 422) 		return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 423) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 424) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 425) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 426) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 427) void trap_is_kprobe(unsigned long address, struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 428) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 429) 	notify_die(DIE_TRAP, "kprobe_trap", regs, address, 0, SIGTRAP);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 430) }