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	/*
41	 * On interrupt, gs and __gsh store the vector number.  They never
42	 * store gs any more.
43	 */
44	unsigned short gs;
45	unsigned short __gsh;
46	/* On interrupt, this is the error code. */
47	unsigned long orig_ax;
48	unsigned long ip;
49	unsigned short cs;
50	unsigned short __csh;
51	unsigned long flags;
52	unsigned long sp;
53	unsigned short ss;
54	unsigned short __ssh;
55};
56
57#else /* __i386__ */
58
59struct fred_cs {
60		/* CS selector */
61	u64	cs	: 16,
62		/* Stack level at event time */
63		sl	:  2,
64		/* IBT in WAIT_FOR_ENDBRANCH state */
65		wfe	:  1,
66			: 45;
67};
68
69struct fred_ss {
70		/* SS selector */
71	u64	ss	: 16,
72		/* STI state */
73		sti	:  1,
74		/* Set if syscall, sysenter or INT n */
75		swevent	:  1,
76		/* Event is NMI type */
77		nmi	:  1,
78			: 13,
79		/* Event vector */
80		vector	:  8,
81			:  8,
82		/* Event type */
83		type	:  4,
84			:  4,
85		/* Event was incident to enclave execution */
86		enclave	:  1,
87		/* CPU was in long mode */
88		lm	:  1,
89		/*
90		 * Nested exception during FRED delivery, not set
91		 * for #DF.
92		 */
93		nested	:  1,
94			:  1,
95		/*
96		 * The length of the instruction causing the event.
97		 * Only set for INTO, INT1, INT3, INT n, SYSCALL
98		 * and SYSENTER.  0 otherwise.
99		 */
100		insnlen	:  4;
101};
102
103struct pt_regs {
104	/*
105	 * C ABI says these regs are callee-preserved. They aren't saved on
106	 * kernel entry unless syscall needs a complete, fully filled
107	 * "struct pt_regs".
108	 */
109	unsigned long r15;
110	unsigned long r14;
111	unsigned long r13;
112	unsigned long r12;
113	unsigned long bp;
114	unsigned long bx;
115
116	/* These regs are callee-clobbered. Always saved on kernel entry. */
117	unsigned long r11;
118	unsigned long r10;
119	unsigned long r9;
120	unsigned long r8;
121	unsigned long ax;
122	unsigned long cx;
123	unsigned long dx;
124	unsigned long si;
125	unsigned long di;
126
127	/*
128	 * orig_ax is used on entry for:
129	 * - the syscall number (syscall, sysenter, int80)
130	 * - error_code stored by the CPU on traps and exceptions
131	 * - the interrupt number for device interrupts
132	 *
133	 * A FRED stack frame starts here:
134	 *   1) It _always_ includes an error code;
135	 *
136	 *   2) The return frame for ERET[US] starts here, but
137	 *      the content of orig_ax is ignored.
138	 */
139	unsigned long orig_ax;
140
141	/* The IRETQ return frame starts here */
142	unsigned long ip;
143
144	union {
145		/* CS selector */
146		u16		cs;
147		/* The extended 64-bit data slot containing CS */
148		u64		csx;
149		/* The FRED CS extension */
150		struct fred_cs	fred_cs;
151	};
152
153	unsigned long flags;
154	unsigned long sp;
155
156	union {
157		/* SS selector */
158		u16		ss;
159		/* The extended 64-bit data slot containing SS */
160		u64		ssx;
161		/* The FRED SS extension */
162		struct fred_ss	fred_ss;
163	};
164
165	/*
166	 * Top of stack on IDT systems, while FRED systems have extra fields
167	 * defined above for storing exception related information, e.g. CR2 or
168	 * DR6.
169	 */
170};
171
172#endif /* !__i386__ */
173
174#ifdef CONFIG_PARAVIRT
175#include <asm/paravirt_types.h>
176#endif
177
178#include <asm/proto.h>
179
180struct cpuinfo_x86;
181struct task_struct;
182
183extern unsigned long profile_pc(struct pt_regs *regs);
184
185extern unsigned long
186convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs);
187extern void send_sigtrap(struct pt_regs *regs, int error_code, int si_code);
188
189
190static inline unsigned long regs_return_value(struct pt_regs *regs)
191{
192	return regs->ax;
193}
194
195static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
196{
197	regs->ax = rc;
198}
199
200/*
201 * user_mode(regs) determines whether a register set came from user
202 * mode.  On x86_32, this is true if V8086 mode was enabled OR if the
203 * register set was from protected mode with RPL-3 CS value.  This
204 * tricky test checks that with one comparison.
205 *
206 * On x86_64, vm86 mode is mercifully nonexistent, and we don't need
207 * the extra check.
208 */
209static __always_inline int user_mode(struct pt_regs *regs)
210{
211#ifdef CONFIG_X86_32
212	return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >= USER_RPL;
213#else
214	return !!(regs->cs & 3);
215#endif
216}
217
218static __always_inline int v8086_mode(struct pt_regs *regs)
219{
220#ifdef CONFIG_X86_32
221	return (regs->flags & X86_VM_MASK);
222#else
223	return 0;	/* No V86 mode support in long mode */
224#endif
225}
226
227static inline bool user_64bit_mode(struct pt_regs *regs)
228{
229#ifdef CONFIG_X86_64
230#ifndef CONFIG_PARAVIRT_XXL
231	/*
232	 * On non-paravirt systems, this is the only long mode CPL 3
233	 * selector.  We do not allow long mode selectors in the LDT.
234	 */
235	return regs->cs == __USER_CS;
236#else
237	/* Headers are too twisted for this to go in paravirt.h. */
238	return regs->cs == __USER_CS || regs->cs == pv_info.extra_user_64bit_cs;
239#endif
240#else /* !CONFIG_X86_64 */
241	return false;
242#endif
243}
244
245/*
246 * Determine whether the register set came from any context that is running in
247 * 64-bit mode.
248 */
249static inline bool any_64bit_mode(struct pt_regs *regs)
250{
251#ifdef CONFIG_X86_64
252	return !user_mode(regs) || user_64bit_mode(regs);
253#else
254	return false;
255#endif
256}
257
258#ifdef CONFIG_X86_64
259#define current_user_stack_pointer()	current_pt_regs()->sp
260#define compat_user_stack_pointer()	current_pt_regs()->sp
261
262static __always_inline bool ip_within_syscall_gap(struct pt_regs *regs)
263{
264	bool ret = (regs->ip >= (unsigned long)entry_SYSCALL_64 &&
265		    regs->ip <  (unsigned long)entry_SYSCALL_64_safe_stack);
266
267	ret = ret || (regs->ip >= (unsigned long)entry_SYSRETQ_unsafe_stack &&
268		      regs->ip <  (unsigned long)entry_SYSRETQ_end);
269#ifdef CONFIG_IA32_EMULATION
270	ret = ret || (regs->ip >= (unsigned long)entry_SYSCALL_compat &&
271		      regs->ip <  (unsigned long)entry_SYSCALL_compat_safe_stack);
272	ret = ret || (regs->ip >= (unsigned long)entry_SYSRETL_compat_unsafe_stack &&
273		      regs->ip <  (unsigned long)entry_SYSRETL_compat_end);
274#endif
275
276	return ret;
277}
278#endif
279
280static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
281{
282	return regs->sp;
283}
284
285static inline unsigned long instruction_pointer(struct pt_regs *regs)
286{
287	return regs->ip;
288}
289
290static inline void instruction_pointer_set(struct pt_regs *regs,
291		unsigned long val)
292{
293	regs->ip = val;
294}
295
296static inline unsigned long frame_pointer(struct pt_regs *regs)
297{
298	return regs->bp;
299}
300
301static inline unsigned long user_stack_pointer(struct pt_regs *regs)
302{
303	return regs->sp;
304}
305
306static inline void user_stack_pointer_set(struct pt_regs *regs,
307		unsigned long val)
308{
309	regs->sp = val;
310}
311
312static __always_inline bool regs_irqs_disabled(struct pt_regs *regs)
313{
314	return !(regs->flags & X86_EFLAGS_IF);
315}
316
317/* Query offset/name of register from its name/offset */
318extern int regs_query_register_offset(const char *name);
319extern const char *regs_query_register_name(unsigned int offset);
320#define MAX_REG_OFFSET (offsetof(struct pt_regs, ss))
321
322/**
323 * regs_get_register() - get register value from its offset
324 * @regs:	pt_regs from which register value is gotten.
325 * @offset:	offset number of the register.
326 *
327 * regs_get_register returns the value of a register. The @offset is the
328 * offset of the register in struct pt_regs address which specified by @regs.
329 * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
330 */
331static inline unsigned long regs_get_register(struct pt_regs *regs,
332					      unsigned int offset)
333{
334	if (unlikely(offset > MAX_REG_OFFSET))
335		return 0;
336#ifdef CONFIG_X86_32
337	/* The selector fields are 16-bit. */
338	if (offset == offsetof(struct pt_regs, cs) ||
339	    offset == offsetof(struct pt_regs, ss) ||
340	    offset == offsetof(struct pt_regs, ds) ||
341	    offset == offsetof(struct pt_regs, es) ||
342	    offset == offsetof(struct pt_regs, fs) ||
343	    offset == offsetof(struct pt_regs, gs)) {
344		return *(u16 *)((unsigned long)regs + offset);
345
346	}
347#endif
348	return *(unsigned long *)((unsigned long)regs + offset);
349}
350
351/**
352 * regs_within_kernel_stack() - check the address in the stack
353 * @regs:	pt_regs which contains kernel stack pointer.
354 * @addr:	address which is checked.
355 *
356 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
357 * If @addr is within the kernel stack, it returns true. If not, returns false.
358 */
359static inline int regs_within_kernel_stack(struct pt_regs *regs,
360					   unsigned long addr)
361{
362	return ((addr & ~(THREAD_SIZE - 1)) == (regs->sp & ~(THREAD_SIZE - 1)));
363}
364
365/**
366 * regs_get_kernel_stack_nth_addr() - get the address of the Nth entry on stack
367 * @regs:	pt_regs which contains kernel stack pointer.
368 * @n:		stack entry number.
369 *
370 * regs_get_kernel_stack_nth() returns the address of the @n th entry of the
371 * kernel stack which is specified by @regs. If the @n th entry is NOT in
372 * the kernel stack, this returns NULL.
373 */
374static inline unsigned long *regs_get_kernel_stack_nth_addr(struct pt_regs *regs, unsigned int n)
375{
376	unsigned long *addr = (unsigned long *)regs->sp;
377
378	addr += n;
379	if (regs_within_kernel_stack(regs, (unsigned long)addr))
380		return addr;
381	else
382		return NULL;
383}
384
385/* To avoid include hell, we can't include uaccess.h */
386extern long copy_from_kernel_nofault(void *dst, const void *src, size_t size);
387
388/**
389 * regs_get_kernel_stack_nth() - get Nth entry of the stack
390 * @regs:	pt_regs which contains kernel stack pointer.
391 * @n:		stack entry number.
392 *
393 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
394 * is specified by @regs. If the @n th entry is NOT in the kernel stack
395 * this returns 0.
396 */
397static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
398						      unsigned int n)
399{
400	unsigned long *addr;
401	unsigned long val;
402	long ret;
403
404	addr = regs_get_kernel_stack_nth_addr(regs, n);
405	if (addr) {
406		ret = copy_from_kernel_nofault(&val, addr, sizeof(val));
407		if (!ret)
408			return val;
409	}
410	return 0;
411}
412
413/**
414 * regs_get_kernel_argument() - get Nth function argument in kernel
415 * @regs:	pt_regs of that context
416 * @n:		function argument number (start from 0)
417 *
418 * regs_get_argument() returns @n th argument of the function call.
419 * Note that this chooses most probably assignment, in some case
420 * it can be incorrect.
421 * This is expected to be called from kprobes or ftrace with regs
422 * where the top of stack is the return address.
423 */
424static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs,
425						     unsigned int n)
426{
427	static const unsigned int argument_offs[] = {
428#ifdef __i386__
429		offsetof(struct pt_regs, ax),
430		offsetof(struct pt_regs, dx),
431		offsetof(struct pt_regs, cx),
432#define NR_REG_ARGUMENTS 3
433#else
434		offsetof(struct pt_regs, di),
435		offsetof(struct pt_regs, si),
436		offsetof(struct pt_regs, dx),
437		offsetof(struct pt_regs, cx),
438		offsetof(struct pt_regs, r8),
439		offsetof(struct pt_regs, r9),
440#define NR_REG_ARGUMENTS 6
441#endif
442	};
443
444	if (n >= NR_REG_ARGUMENTS) {
445		n -= NR_REG_ARGUMENTS - 1;
446		return regs_get_kernel_stack_nth(regs, n);
447	} else
448		return regs_get_register(regs, argument_offs[n]);
449}
450
451#define arch_has_single_step()	(1)
452#ifdef CONFIG_X86_DEBUGCTLMSR
453#define arch_has_block_step()	(1)
454#else
455#define arch_has_block_step()	(boot_cpu_data.x86 >= 6)
456#endif
457
458#define ARCH_HAS_USER_SINGLE_STEP_REPORT
459
460struct user_desc;
461extern int do_get_thread_area(struct task_struct *p, int idx,
462			      struct user_desc __user *info);
463extern int do_set_thread_area(struct task_struct *p, int idx,
464			      struct user_desc __user *info, int can_allocate);
465
466#ifdef CONFIG_X86_64
467# define do_set_thread_area_64(p, s, t)	do_arch_prctl_64(p, s, t)
468#else
469# define do_set_thread_area_64(p, s, t)	(0)
470#endif
471
472#endif /* !__ASSEMBLY__ */
473#endif /* _ASM_X86_PTRACE_H */
474