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 __ASSEMBLER__
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, addr: (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(dst: &val, src: addr, size: 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, offset: 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 /* !__ASSEMBLER__ */
473#endif /* _ASM_X86_PTRACE_H */
474

source code of linux/arch/x86/include/asm/ptrace.h