1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2014-2016 Pratyush Anand <panand@redhat.com>
  4 */
  5#include <linux/highmem.h>
  6#include <linux/ptrace.h>
  7#include <linux/uprobes.h>
  8#include <asm/cacheflush.h>
  9
 10#include "decode-insn.h"
 11
 12#define UPROBE_TRAP_NR	UINT_MAX
 13
 14bool is_swbp_insn(uprobe_opcode_t *insn)
 15{
 16	return (*insn & 0xffff) == UPROBE_SWBP_INSN;
 17}
 18
 19unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
 20{
 21	return instruction_pointer(regs);
 22}
 23
 24int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
 25		unsigned long addr)
 26{
 27	probe_opcode_t insn;
 28
 29	insn = *(probe_opcode_t *)(&auprobe->insn[0]);
 30
 31	auprobe->insn_size = is_insn32(insn) ? 4 : 2;
 32
 33	switch (csky_probe_decode_insn(&insn, &auprobe->api)) {
 34	case INSN_REJECTED:
 35		return -EINVAL;
 36
 37	case INSN_GOOD_NO_SLOT:
 38		auprobe->simulate = true;
 39		break;
 40
 41	default:
 42		break;
 43	}
 44
 45	return 0;
 46}
 47
 48int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 49{
 50	struct uprobe_task *utask = current->utask;
 51
 52	utask->autask.saved_trap_no = current->thread.trap_no;
 53	current->thread.trap_no = UPROBE_TRAP_NR;
 54
 55	instruction_pointer_set(regs, utask->xol_vaddr);
 56
 57	user_enable_single_step(current);
 58
 59	return 0;
 60}
 61
 62int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 63{
 64	struct uprobe_task *utask = current->utask;
 65
 66	WARN_ON_ONCE(current->thread.trap_no != UPROBE_TRAP_NR);
 67	current->thread.trap_no = utask->autask.saved_trap_no;
 68
 69	instruction_pointer_set(regs, utask->vaddr + auprobe->insn_size);
 70
 71	user_disable_single_step(current);
 72
 73	return 0;
 74}
 75
 76bool arch_uprobe_xol_was_trapped(struct task_struct *t)
 77{
 78	if (t->thread.trap_no != UPROBE_TRAP_NR)
 79		return true;
 80
 81	return false;
 82}
 83
 84bool 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
101void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
102{
103	struct uprobe_task *utask = current->utask;
104
105	current->thread.trap_no = utask->autask.saved_trap_no;
106
107	/*
108	 * Task has received a fatal signal, so reset back to probed
109	 * address.
110	 */
111	instruction_pointer_set(regs, utask->vaddr);
112
113	user_disable_single_step(current);
114}
115
116bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx,
117		struct pt_regs *regs)
118{
119	if (ctx == RP_CHECK_CHAIN_CALL)
120		return regs->usp <= ret->stack;
121	else
122		return regs->usp < ret->stack;
123}
124
125unsigned long
126arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
127				  struct pt_regs *regs)
128{
129	unsigned long ra;
130
131	ra = regs->lr;
132
133	regs->lr = trampoline_vaddr;
134
135	return ra;
136}
137
138int arch_uprobe_exception_notify(struct notifier_block *self,
139				 unsigned long val, void *data)
140{
141	return NOTIFY_DONE;
142}
143
144int uprobe_breakpoint_handler(struct pt_regs *regs)
145{
146	if (uprobe_pre_sstep_notifier(regs))
147		return 1;
148
149	return 0;
150}
151
152int uprobe_single_step_handler(struct pt_regs *regs)
153{
154	if (uprobe_post_sstep_notifier(regs))
155		return 1;
156
157	return 0;
158}