1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 2020 Loongson Technology Co., Ltd.
4 */
5#ifndef _ASM_PTRACE_H
6#define _ASM_PTRACE_H
7
8#include <asm/page.h>
9#include <asm/irqflags.h>
10#include <asm/thread_info.h>
11#include <uapi/asm/ptrace.h>
12
13/*
14 * This struct defines the way the registers are stored on the stack during
15 * a system call/exception. If you add a register here, please also add it to
16 * regoffset_table[] in arch/loongarch/kernel/ptrace.c.
17 */
18struct pt_regs {
19	/* Main processor registers. */
20	unsigned long regs[32];
21
22	/* Original syscall arg0. */
23	unsigned long orig_a0;
24
25	/* Special CSR registers. */
26	unsigned long csr_era;
27	unsigned long csr_badvaddr;
28	unsigned long csr_crmd;
29	unsigned long csr_prmd;
30	unsigned long csr_euen;
31	unsigned long csr_ecfg;
32	unsigned long csr_estat;
33	unsigned long __last[];
34} __aligned(8);
35
36static inline int regs_irqs_disabled(struct pt_regs *regs)
37{
38	return arch_irqs_disabled_flags(regs->csr_prmd);
39}
40
41static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
42{
43	return regs->regs[3];
44}
45
46/*
47 * Don't use asm-generic/ptrace.h it defines FP accessors that don't make
48 * sense on LoongArch.  We rather want an error if they get invoked.
49 */
50
51static inline void instruction_pointer_set(struct pt_regs *regs,
52                                           unsigned long val)
53{
54	regs->csr_era = val;
55}
56
57/* Query offset/name of register from its name/offset */
58extern int regs_query_register_offset(const char *name);
59#define MAX_REG_OFFSET (offsetof(struct pt_regs, __last))
60
61/**
62 * regs_get_register() - get register value from its offset
63 * @regs:       pt_regs from which register value is gotten.
64 * @offset:     offset number of the register.
65 *
66 * regs_get_register returns the value of a register. The @offset is the
67 * offset of the register in struct pt_regs address which specified by @regs.
68 * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
69 */
70static inline unsigned long regs_get_register(struct pt_regs *regs,
71                                              unsigned int offset)
72{
73	if (unlikely(offset > MAX_REG_OFFSET))
74		return 0;
75
76	return *(unsigned long *)((unsigned long)regs + offset);
77}
78
79/**
80 * regs_within_kernel_stack() - check the address in the stack
81 * @regs:       pt_regs which contains kernel stack pointer.
82 * @addr:       address which is checked.
83 *
84 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
85 * If @addr is within the kernel stack, it returns true. If not, returns false.
86 */
87static inline int regs_within_kernel_stack(struct pt_regs *regs,
88                                           unsigned long addr)
89{
90	return ((addr & ~(THREAD_SIZE - 1))  ==
91		(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
92}
93
94/**
95 * regs_get_kernel_stack_nth() - get Nth entry of the stack
96 * @regs:       pt_regs which contains kernel stack pointer.
97 * @n:          stack entry number.
98 *
99 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
100 * is specified by @regs. If the @n th entry is NOT in the kernel stack,
101 * this returns 0.
102 */
103static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
104                                                      unsigned int n)
105{
106	unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
107
108	addr += n;
109	if (regs_within_kernel_stack(regs, (unsigned long)addr))
110		return *addr;
111	else
112		return 0;
113}
114
115struct task_struct;
116
117/*
118 * Does the process account for user or for system time?
119 */
120#define user_mode(regs) (((regs)->csr_prmd & PLV_MASK) == PLV_USER)
121
122static inline long regs_return_value(struct pt_regs *regs)
123{
124	return regs->regs[4];
125}
126
127#define instruction_pointer(regs) ((regs)->csr_era)
128#define profile_pc(regs) instruction_pointer(regs)
129
130extern void die(const char *, struct pt_regs *) __noreturn;
131
132static inline void die_if_kernel(const char *str, struct pt_regs *regs)
133{
134	if (unlikely(!user_mode(regs)))
135		die(str, regs);
136}
137
138#define current_pt_regs()						\
139({									\
140	unsigned long sp = (unsigned long)__builtin_frame_address(0);	\
141	(struct pt_regs *)((sp | (THREAD_SIZE - 1)) + 1) - 1;		\
142})
143
144/* Helpers for working with the user stack pointer */
145
146static inline unsigned long user_stack_pointer(struct pt_regs *regs)
147{
148	return regs->regs[3];
149}
150
151static inline void user_stack_pointer_set(struct pt_regs *regs,
152	unsigned long val)
153{
154	regs->regs[3] = val;
155}
156
157#define arch_has_single_step()  (1)
158
159#endif /* _ASM_PTRACE_H */
160