1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_PTRACE_H
3 #define _ASM_X86_PTRACE_H
5 #include <asm/segment.h>
6 #include <asm/page_types.h>
7 #include <uapi/asm/ptrace.h>
14 * NB: 32-bit x86 CPUs are inconsistent as what happens in the
15 * following cases (where %seg represents a segment register):
17 * - pushl %seg: some do a 16-bit write and leave the high
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.
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
40 /* On interrupt, gs and __gsh store the vector number. */
43 /* On interrupt, this is the error code. */
44 unsigned long orig_ax;
58 * C ABI says these regs are callee-preserved. They aren't saved on kernel entry
59 * unless syscall needs a complete, fully filled "struct pt_regs".
67 /* These regs are callee-clobbered. Always saved on kernel entry. */
78 * On syscall entry, this is syscall#. On CPU exception, this is error code.
79 * On hw interrupt, it's IRQ number:
81 unsigned long orig_ax;
82 /* Return frame for iretq */
88 /* top of stack page */
91 #endif /* !__i386__ */
93 #ifdef CONFIG_PARAVIRT
94 #include <asm/paravirt_types.h>
100 extern unsigned long profile_pc(struct pt_regs *regs);
103 convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs);
104 extern void send_sigtrap(struct pt_regs *regs, int error_code, int si_code);
107 static inline unsigned long regs_return_value(struct pt_regs *regs)
112 static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
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.
123 * On x86_64, vm86 mode is mercifully nonexistent, and we don't need
126 static inline int user_mode(struct pt_regs *regs)
129 return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >= USER_RPL;
131 return !!(regs->cs & 3);
135 static inline int v8086_mode(struct pt_regs *regs)
138 return (regs->flags & X86_VM_MASK);
140 return 0; /* No V86 mode support in long mode */
144 static inline bool user_64bit_mode(struct pt_regs *regs)
147 #ifndef CONFIG_PARAVIRT_XXL
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.
152 return regs->cs == __USER_CS;
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;
157 #else /* !CONFIG_X86_64 */
163 #define current_user_stack_pointer() current_pt_regs()->sp
164 #define compat_user_stack_pointer() current_pt_regs()->sp
167 static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
172 static inline unsigned long instruction_pointer(struct pt_regs *regs)
177 static inline void instruction_pointer_set(struct pt_regs *regs,
183 static inline unsigned long frame_pointer(struct pt_regs *regs)
188 static inline unsigned long user_stack_pointer(struct pt_regs *regs)
193 static inline void user_stack_pointer_set(struct pt_regs *regs,
199 /* Query offset/name of register from its name/offset */
200 extern int regs_query_register_offset(const char *name);
201 extern const char *regs_query_register_name(unsigned int offset);
202 #define MAX_REG_OFFSET (offsetof(struct pt_regs, ss))
205 * regs_get_register() - get register value from its offset
206 * @regs: pt_regs from which register value is gotten.
207 * @offset: offset number of the register.
209 * regs_get_register returns the value of a register. The @offset is the
210 * offset of the register in struct pt_regs address which specified by @regs.
211 * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
213 static inline unsigned long regs_get_register(struct pt_regs *regs,
216 if (unlikely(offset > MAX_REG_OFFSET))
219 /* The selector fields are 16-bit. */
220 if (offset == offsetof(struct pt_regs, cs) ||
221 offset == offsetof(struct pt_regs, ss) ||
222 offset == offsetof(struct pt_regs, ds) ||
223 offset == offsetof(struct pt_regs, es) ||
224 offset == offsetof(struct pt_regs, fs) ||
225 offset == offsetof(struct pt_regs, gs)) {
226 return *(u16 *)((unsigned long)regs + offset);
230 return *(unsigned long *)((unsigned long)regs + offset);
234 * regs_within_kernel_stack() - check the address in the stack
235 * @regs: pt_regs which contains kernel stack pointer.
236 * @addr: address which is checked.
238 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
239 * If @addr is within the kernel stack, it returns true. If not, returns false.
241 static inline int regs_within_kernel_stack(struct pt_regs *regs,
244 return ((addr & ~(THREAD_SIZE - 1)) == (regs->sp & ~(THREAD_SIZE - 1)));
248 * regs_get_kernel_stack_nth_addr() - get the address of the Nth entry on stack
249 * @regs: pt_regs which contains kernel stack pointer.
250 * @n: stack entry number.
252 * regs_get_kernel_stack_nth() returns the address of the @n th entry of the
253 * kernel stack which is specified by @regs. If the @n th entry is NOT in
254 * the kernel stack, this returns NULL.
256 static inline unsigned long *regs_get_kernel_stack_nth_addr(struct pt_regs *regs, unsigned int n)
258 unsigned long *addr = (unsigned long *)regs->sp;
261 if (regs_within_kernel_stack(regs, (unsigned long)addr))
267 /* To avoid include hell, we can't include uaccess.h */
268 extern long probe_kernel_read(void *dst, const void *src, size_t size);
271 * regs_get_kernel_stack_nth() - get Nth entry of the stack
272 * @regs: pt_regs which contains kernel stack pointer.
273 * @n: stack entry number.
275 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
276 * is specified by @regs. If the @n th entry is NOT in the kernel stack
279 static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
286 addr = regs_get_kernel_stack_nth_addr(regs, n);
288 ret = probe_kernel_read(&val, addr, sizeof(val));
296 * regs_get_kernel_argument() - get Nth function argument in kernel
297 * @regs: pt_regs of that context
298 * @n: function argument number (start from 0)
300 * regs_get_argument() returns @n th argument of the function call.
301 * Note that this chooses most probably assignment, in some case
302 * it can be incorrect.
303 * This is expected to be called from kprobes or ftrace with regs
304 * where the top of stack is the return address.
306 static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs,
309 static const unsigned int argument_offs[] = {
311 offsetof(struct pt_regs, ax),
312 offsetof(struct pt_regs, cx),
313 offsetof(struct pt_regs, dx),
314 #define NR_REG_ARGUMENTS 3
316 offsetof(struct pt_regs, di),
317 offsetof(struct pt_regs, si),
318 offsetof(struct pt_regs, dx),
319 offsetof(struct pt_regs, cx),
320 offsetof(struct pt_regs, r8),
321 offsetof(struct pt_regs, r9),
322 #define NR_REG_ARGUMENTS 6
326 if (n >= NR_REG_ARGUMENTS) {
327 n -= NR_REG_ARGUMENTS - 1;
328 return regs_get_kernel_stack_nth(regs, n);
330 return regs_get_register(regs, argument_offs[n]);
333 #define arch_has_single_step() (1)
334 #ifdef CONFIG_X86_DEBUGCTLMSR
335 #define arch_has_block_step() (1)
337 #define arch_has_block_step() (boot_cpu_data.x86 >= 6)
340 #define ARCH_HAS_USER_SINGLE_STEP_REPORT
343 * When hitting ptrace_stop(), we cannot return using SYSRET because
344 * that does not restore the full CPU state, only a minimal set. The
345 * ptracer can change arbitrary register values, which is usually okay
346 * because the usual ptrace stops run off the signal delivery path which
347 * forces IRET; however, ptrace_event() stops happen in arbitrary places
348 * in the kernel and don't force IRET path.
350 * So force IRET path after a ptrace stop.
352 #define arch_ptrace_stop_needed(code, info) \
359 extern int do_get_thread_area(struct task_struct *p, int idx,
360 struct user_desc __user *info);
361 extern int do_set_thread_area(struct task_struct *p, int idx,
362 struct user_desc __user *info, int can_allocate);
365 # define do_set_thread_area_64(p, s, t) do_arch_prctl_64(p, s, t)
367 # define do_set_thread_area_64(p, s, t) (0)
370 #endif /* !__ASSEMBLY__ */
371 #endif /* _ASM_X86_PTRACE_H */