1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_X86_PTRACE_H
3#define _ASM_X86_PTRACE_H
4
5#include <asm/segment.h>
6#include <asm/page_types.h>
7#include <uapi/asm/ptrace.h>
8
9#ifndef __ASSEMBLY__
10#ifdef __i386__
11
12struct pt_regs {
13 /*
14 * NB: 32-bit x86 CPUs are inconsistent as what happens in the
15 * following cases (where %seg represents a segment register):
16 *
17 * - pushl %seg: some do a 16-bit write and leave the high
18 * bits alone
19 * - movl %seg, [mem]: some do a 16-bit write despite the movl
20 * - IDT entry: some (e.g. 486) will leave the high bits of CS
21 * and (if applicable) SS undefined.
22 *
23 * Fortunately, x86-32 doesn't read the high bits on POP or IRET,
24 * so we can just treat all of the segment registers as 16-bit
25 * values.
26 */
27 unsigned long bx;
28 unsigned long cx;
29 unsigned long dx;
30 unsigned long si;
31 unsigned long di;
32 unsigned long bp;
33 unsigned long ax;
34 unsigned short ds;
35 unsigned short __dsh;
36 unsigned short es;
37 unsigned short __esh;
38 unsigned short fs;
39 unsigned short __fsh;
40 unsigned short gs;
41 unsigned short __gsh;
42 unsigned long orig_ax;
43 unsigned long ip;
44 unsigned short cs;
45 unsigned short __csh;
46 unsigned long flags;
47 unsigned long sp;
48 unsigned short ss;
49 unsigned short __ssh;
50};
51
52#else /* __i386__ */
53
54struct pt_regs {
55/*
56 * C ABI says these regs are callee-preserved. They aren't saved on kernel entry
57 * unless syscall needs a complete, fully filled "struct pt_regs".
58 */
59 unsigned long r15;
60 unsigned long r14;
61 unsigned long r13;
62 unsigned long r12;
63 unsigned long bp;
64 unsigned long bx;
65/* These regs are callee-clobbered. Always saved on kernel entry. */
66 unsigned long r11;
67 unsigned long r10;
68 unsigned long r9;
69 unsigned long r8;
70 unsigned long ax;
71 unsigned long cx;
72 unsigned long dx;
73 unsigned long si;
74 unsigned long di;
75/*
76 * On syscall entry, this is syscall#. On CPU exception, this is error code.
77 * On hw interrupt, it's IRQ number:
78 */
79 unsigned long orig_ax;
80/* Return frame for iretq */
81 unsigned long ip;
82 unsigned long cs;
83 unsigned long flags;
84 unsigned long sp;
85 unsigned long ss;
86/* top of stack page */
87};
88
89#endif /* !__i386__ */
90
91#ifdef CONFIG_PARAVIRT
92#include <asm/paravirt_types.h>
93#endif
94
95struct cpuinfo_x86;
96struct task_struct;
97
98extern unsigned long profile_pc(struct pt_regs *regs);
99#define profile_pc profile_pc
100
101extern unsigned long
102convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs);
103extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
104 int error_code, int si_code);
105
106
107static inline unsigned long regs_return_value(struct pt_regs *regs)
108{
109 return regs->ax;
110}
111
112static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
113{
114 regs->ax = rc;
115}
116
117/*
118 * user_mode(regs) determines whether a register set came from user
119 * mode. On x86_32, this is true if V8086 mode was enabled OR if the
120 * register set was from protected mode with RPL-3 CS value. This
121 * tricky test checks that with one comparison.
122 *
123 * On x86_64, vm86 mode is mercifully nonexistent, and we don't need
124 * the extra check.
125 */
126static inline int user_mode(struct pt_regs *regs)
127{
128#ifdef CONFIG_X86_32
129 return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >= USER_RPL;
130#else
131 return !!(regs->cs & 3);
132#endif
133}
134
135static inline int v8086_mode(struct pt_regs *regs)
136{
137#ifdef CONFIG_X86_32
138 return (regs->flags & X86_VM_MASK);
139#else
140 return 0; /* No V86 mode support in long mode */
141#endif
142}
143
144static inline bool user_64bit_mode(struct pt_regs *regs)
145{
146#ifdef CONFIG_X86_64
147#ifndef CONFIG_PARAVIRT
148 /*
149 * On non-paravirt systems, this is the only long mode CPL 3
150 * selector. We do not allow long mode selectors in the LDT.
151 */
152 return regs->cs == __USER_CS;
153#else
154 /* Headers are too twisted for this to go in paravirt.h. */
155 return regs->cs == __USER_CS || regs->cs == pv_info.extra_user_64bit_cs;
156#endif
157#else /* !CONFIG_X86_64 */
158 return false;
159#endif
160}
161
162#ifdef CONFIG_X86_64
163#define current_user_stack_pointer() current_pt_regs()->sp
164#define compat_user_stack_pointer() current_pt_regs()->sp
165#endif
166
167#ifdef CONFIG_X86_32
168extern unsigned long kernel_stack_pointer(struct pt_regs *regs);
169#else
170static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
171{
172 return regs->sp;
173}
174#endif
175
176#define GET_IP(regs) ((regs)->ip)
177#define GET_FP(regs) ((regs)->bp)
178#define GET_USP(regs) ((regs)->sp)
179
180#include <asm-generic/ptrace.h>
181
182/* Query offset/name of register from its name/offset */
183extern int regs_query_register_offset(const char *name);
184extern const char *regs_query_register_name(unsigned int offset);
185#define MAX_REG_OFFSET (offsetof(struct pt_regs, ss))
186
187/**
188 * regs_get_register() - get register value from its offset
189 * @regs: pt_regs from which register value is gotten.
190 * @offset: offset number of the register.
191 *
192 * regs_get_register returns the value of a register. The @offset is the
193 * offset of the register in struct pt_regs address which specified by @regs.
194 * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
195 */
196static inline unsigned long regs_get_register(struct pt_regs *regs,
197 unsigned int offset)
198{
199 if (unlikely(offset > MAX_REG_OFFSET))
200 return 0;
201#ifdef CONFIG_X86_32
202 /*
203 * Traps from the kernel do not save sp and ss.
204 * Use the helper function to retrieve sp.
205 */
206 if (offset == offsetof(struct pt_regs, sp) &&
207 regs->cs == __KERNEL_CS)
208 return kernel_stack_pointer(regs);
209
210 /* The selector fields are 16-bit. */
211 if (offset == offsetof(struct pt_regs, cs) ||
212 offset == offsetof(struct pt_regs, ss) ||
213 offset == offsetof(struct pt_regs, ds) ||
214 offset == offsetof(struct pt_regs, es) ||
215 offset == offsetof(struct pt_regs, fs) ||
216 offset == offsetof(struct pt_regs, gs)) {
217 return *(u16 *)((unsigned long)regs + offset);
218
219 }
220#endif
221 return *(unsigned long *)((unsigned long)regs + offset);
222}
223
224/**
225 * regs_within_kernel_stack() - check the address in the stack
226 * @regs: pt_regs which contains kernel stack pointer.
227 * @addr: address which is checked.
228 *
229 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
230 * If @addr is within the kernel stack, it returns true. If not, returns false.
231 */
232static inline int regs_within_kernel_stack(struct pt_regs *regs,
233 unsigned long addr)
234{
235 return ((addr & ~(THREAD_SIZE - 1)) ==
236 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
237}
238
239/**
240 * regs_get_kernel_stack_nth() - get Nth entry of the stack
241 * @regs: pt_regs which contains kernel stack pointer.
242 * @n: stack entry number.
243 *
244 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
245 * is specified by @regs. If the @n th entry is NOT in the kernel stack,
246 * this returns 0.
247 */
248static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
249 unsigned int n)
250{
251 unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
252 addr += n;
253 if (regs_within_kernel_stack(regs, (unsigned long)addr))
254 return *addr;
255 else
256 return 0;
257}
258
259#define arch_has_single_step() (1)
260#ifdef CONFIG_X86_DEBUGCTLMSR
261#define arch_has_block_step() (1)
262#else
263#define arch_has_block_step() (boot_cpu_data.x86 >= 6)
264#endif
265
266#define ARCH_HAS_USER_SINGLE_STEP_INFO
267
268/*
269 * When hitting ptrace_stop(), we cannot return using SYSRET because
270 * that does not restore the full CPU state, only a minimal set. The
271 * ptracer can change arbitrary register values, which is usually okay
272 * because the usual ptrace stops run off the signal delivery path which
273 * forces IRET; however, ptrace_event() stops happen in arbitrary places
274 * in the kernel and don't force IRET path.
275 *
276 * So force IRET path after a ptrace stop.
277 */
278#define arch_ptrace_stop_needed(code, info) \
279({ \
280 force_iret(); \
281 false; \
282})
283
284struct user_desc;
285extern int do_get_thread_area(struct task_struct *p, int idx,
286 struct user_desc __user *info);
287extern int do_set_thread_area(struct task_struct *p, int idx,
288 struct user_desc __user *info, int can_allocate);
289
290#endif /* !__ASSEMBLY__ */
291#endif /* _ASM_X86_PTRACE_H */
292