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
42 unsigned long orig_ax;
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".
65 /* These regs are callee-clobbered. Always saved on kernel entry. */
76 * On syscall entry, this is syscall#. On CPU exception, this is error code.
77 * On hw interrupt, it's IRQ number:
79 unsigned long orig_ax;
80 /* Return frame for iretq */
86 /* top of stack page */
89 #endif /* !__i386__ */
91 #ifdef CONFIG_PARAVIRT
92 #include <asm/paravirt_types.h>
98 extern unsigned long profile_pc(struct pt_regs *regs);
99 #define profile_pc profile_pc
102 convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs);
103 extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
104 int error_code, int si_code);
107 static inline unsigned long regs_return_value(struct pt_regs *regs)
113 * user_mode(regs) determines whether a register set came from user
114 * mode. On x86_32, this is true if V8086 mode was enabled OR if the
115 * register set was from protected mode with RPL-3 CS value. This
116 * tricky test checks that with one comparison.
118 * On x86_64, vm86 mode is mercifully nonexistent, and we don't need
121 static inline int user_mode(struct pt_regs *regs)
124 return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >= USER_RPL;
126 return !!(regs->cs & 3);
130 static inline int v8086_mode(struct pt_regs *regs)
133 return (regs->flags & X86_VM_MASK);
135 return 0; /* No V86 mode support in long mode */
139 static inline bool user_64bit_mode(struct pt_regs *regs)
142 #ifndef CONFIG_PARAVIRT
144 * On non-paravirt systems, this is the only long mode CPL 3
145 * selector. We do not allow long mode selectors in the LDT.
147 return regs->cs == __USER_CS;
149 /* Headers are too twisted for this to go in paravirt.h. */
150 return regs->cs == __USER_CS || regs->cs == pv_info.extra_user_64bit_cs;
152 #else /* !CONFIG_X86_64 */
158 #define current_user_stack_pointer() current_pt_regs()->sp
159 #define compat_user_stack_pointer() current_pt_regs()->sp
163 extern unsigned long kernel_stack_pointer(struct pt_regs *regs);
165 static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
171 #define GET_IP(regs) ((regs)->ip)
172 #define GET_FP(regs) ((regs)->bp)
173 #define GET_USP(regs) ((regs)->sp)
175 #include <asm-generic/ptrace.h>
177 /* Query offset/name of register from its name/offset */
178 extern int regs_query_register_offset(const char *name);
179 extern const char *regs_query_register_name(unsigned int offset);
180 #define MAX_REG_OFFSET (offsetof(struct pt_regs, ss))
183 * regs_get_register() - get register value from its offset
184 * @regs: pt_regs from which register value is gotten.
185 * @offset: offset number of the register.
187 * regs_get_register returns the value of a register. The @offset is the
188 * offset of the register in struct pt_regs address which specified by @regs.
189 * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
191 static inline unsigned long regs_get_register(struct pt_regs *regs,
194 if (unlikely(offset > MAX_REG_OFFSET))
198 * Traps from the kernel do not save sp and ss.
199 * Use the helper function to retrieve sp.
201 if (offset == offsetof(struct pt_regs, sp) &&
202 regs->cs == __KERNEL_CS)
203 return kernel_stack_pointer(regs);
205 /* The selector fields are 16-bit. */
206 if (offset == offsetof(struct pt_regs, cs) ||
207 offset == offsetof(struct pt_regs, ss) ||
208 offset == offsetof(struct pt_regs, ds) ||
209 offset == offsetof(struct pt_regs, es) ||
210 offset == offsetof(struct pt_regs, fs) ||
211 offset == offsetof(struct pt_regs, gs)) {
212 return *(u16 *)((unsigned long)regs + offset);
216 return *(unsigned long *)((unsigned long)regs + offset);
220 * regs_within_kernel_stack() - check the address in the stack
221 * @regs: pt_regs which contains kernel stack pointer.
222 * @addr: address which is checked.
224 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
225 * If @addr is within the kernel stack, it returns true. If not, returns false.
227 static inline int regs_within_kernel_stack(struct pt_regs *regs,
230 return ((addr & ~(THREAD_SIZE - 1)) ==
231 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
235 * regs_get_kernel_stack_nth_addr() - get the address of the Nth entry on stack
236 * @regs: pt_regs which contains kernel stack pointer.
237 * @n: stack entry number.
239 * regs_get_kernel_stack_nth() returns the address of the @n th entry of the
240 * kernel stack which is specified by @regs. If the @n th entry is NOT in
241 * the kernel stack, this returns NULL.
243 static inline unsigned long *regs_get_kernel_stack_nth_addr(struct pt_regs *regs, unsigned int n)
245 unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
248 if (regs_within_kernel_stack(regs, (unsigned long)addr))
254 /* To avoid include hell, we can't include uaccess.h */
255 extern long probe_kernel_read(void *dst, const void *src, size_t size);
258 * regs_get_kernel_stack_nth() - get Nth entry of the stack
259 * @regs: pt_regs which contains kernel stack pointer.
260 * @n: stack entry number.
262 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
263 * is specified by @regs. If the @n th entry is NOT in the kernel stack
266 static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
273 addr = regs_get_kernel_stack_nth_addr(regs, n);
275 ret = probe_kernel_read(&val, addr, sizeof(val));
282 #define arch_has_single_step() (1)
283 #ifdef CONFIG_X86_DEBUGCTLMSR
284 #define arch_has_block_step() (1)
286 #define arch_has_block_step() (boot_cpu_data.x86 >= 6)
289 #define ARCH_HAS_USER_SINGLE_STEP_INFO
292 * When hitting ptrace_stop(), we cannot return using SYSRET because
293 * that does not restore the full CPU state, only a minimal set. The
294 * ptracer can change arbitrary register values, which is usually okay
295 * because the usual ptrace stops run off the signal delivery path which
296 * forces IRET; however, ptrace_event() stops happen in arbitrary places
297 * in the kernel and don't force IRET path.
299 * So force IRET path after a ptrace stop.
301 #define arch_ptrace_stop_needed(code, info) \
308 extern int do_get_thread_area(struct task_struct *p, int idx,
309 struct user_desc __user *info);
310 extern int do_set_thread_area(struct task_struct *p, int idx,
311 struct user_desc __user *info, int can_allocate);
313 #endif /* !__ASSEMBLY__ */
314 #endif /* _ASM_X86_PTRACE_H */