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
 68	instruction_pointer_set(regs, utask->vaddr + auprobe->insn_size);
 69
 70	user_disable_single_step(current);
 71
 72	return 0;
 73}
 74
 75bool arch_uprobe_xol_was_trapped(struct task_struct *t)
 76{
 77	if (t->thread.trap_no != UPROBE_TRAP_NR)
 78		return true;
 79
 80	return false;
 81}
 82
 83bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
 84{
 85	probe_opcode_t insn;
 86	unsigned long addr;
 87
 88	if (!auprobe->simulate)
 89		return false;
 90
 91	insn = *(probe_opcode_t *)(&auprobe->insn[0]);
 92	addr = instruction_pointer(regs);
 93
 94	if (auprobe->api.handler)
 95		auprobe->api.handler(insn, addr, regs);
 96
 97	return true;
 98}
 99
100void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
101{
102	struct uprobe_task *utask = current->utask;
103
104	/*
105	 * Task has received a fatal signal, so reset back to probed
106	 * address.
107	 */
108	instruction_pointer_set(regs, utask->vaddr);
109
110	user_disable_single_step(current);
111}
112
113bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx,
114		struct pt_regs *regs)
115{
116	if (ctx == RP_CHECK_CHAIN_CALL)
117		return regs->usp <= ret->stack;
118	else
119		return regs->usp < ret->stack;
120}
121
122unsigned long
123arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
124				  struct pt_regs *regs)
125{
126	unsigned long ra;
127
128	ra = regs->lr;
129
130	regs->lr = trampoline_vaddr;
131
132	return ra;
133}
134
135int arch_uprobe_exception_notify(struct notifier_block *self,
136				 unsigned long val, void *data)
137{
138	return NOTIFY_DONE;
139}
140
141int uprobe_breakpoint_handler(struct pt_regs *regs)
142{
143	if (uprobe_pre_sstep_notifier(regs))
144		return 1;
145
146	return 0;
147}
148
149int uprobe_single_step_handler(struct pt_regs *regs)
150{
151	if (uprobe_post_sstep_notifier(regs))
152		return 1;
153
154	return 0;
155}