xref: /openbmc/linux/arch/x86/include/asm/ptrace.h (revision 9cfc5c90)
1 #ifndef _ASM_X86_PTRACE_H
2 #define _ASM_X86_PTRACE_H
3 
4 #include <asm/segment.h>
5 #include <asm/page_types.h>
6 #include <uapi/asm/ptrace.h>
7 
8 #ifndef __ASSEMBLY__
9 #ifdef __i386__
10 
11 struct pt_regs {
12 	unsigned long bx;
13 	unsigned long cx;
14 	unsigned long dx;
15 	unsigned long si;
16 	unsigned long di;
17 	unsigned long bp;
18 	unsigned long ax;
19 	unsigned long ds;
20 	unsigned long es;
21 	unsigned long fs;
22 	unsigned long gs;
23 	unsigned long orig_ax;
24 	unsigned long ip;
25 	unsigned long cs;
26 	unsigned long flags;
27 	unsigned long sp;
28 	unsigned long ss;
29 };
30 
31 #else /* __i386__ */
32 
33 struct pt_regs {
34 /*
35  * C ABI says these regs are callee-preserved. They aren't saved on kernel entry
36  * unless syscall needs a complete, fully filled "struct pt_regs".
37  */
38 	unsigned long r15;
39 	unsigned long r14;
40 	unsigned long r13;
41 	unsigned long r12;
42 	unsigned long bp;
43 	unsigned long bx;
44 /* These regs are callee-clobbered. Always saved on kernel entry. */
45 	unsigned long r11;
46 	unsigned long r10;
47 	unsigned long r9;
48 	unsigned long r8;
49 	unsigned long ax;
50 	unsigned long cx;
51 	unsigned long dx;
52 	unsigned long si;
53 	unsigned long di;
54 /*
55  * On syscall entry, this is syscall#. On CPU exception, this is error code.
56  * On hw interrupt, it's IRQ number:
57  */
58 	unsigned long orig_ax;
59 /* Return frame for iretq */
60 	unsigned long ip;
61 	unsigned long cs;
62 	unsigned long flags;
63 	unsigned long sp;
64 	unsigned long ss;
65 /* top of stack page */
66 };
67 
68 #endif /* !__i386__ */
69 
70 #ifdef CONFIG_PARAVIRT
71 #include <asm/paravirt_types.h>
72 #endif
73 
74 struct cpuinfo_x86;
75 struct task_struct;
76 
77 extern unsigned long profile_pc(struct pt_regs *regs);
78 #define profile_pc profile_pc
79 
80 extern unsigned long
81 convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs);
82 extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
83 			 int error_code, int si_code);
84 
85 
86 extern unsigned long syscall_trace_enter_phase1(struct pt_regs *, u32 arch);
87 extern long syscall_trace_enter_phase2(struct pt_regs *, u32 arch,
88 				       unsigned long phase1_result);
89 
90 extern long syscall_trace_enter(struct pt_regs *);
91 
92 static inline unsigned long regs_return_value(struct pt_regs *regs)
93 {
94 	return regs->ax;
95 }
96 
97 /*
98  * user_mode(regs) determines whether a register set came from user
99  * mode.  On x86_32, this is true if V8086 mode was enabled OR if the
100  * register set was from protected mode with RPL-3 CS value.  This
101  * tricky test checks that with one comparison.
102  *
103  * On x86_64, vm86 mode is mercifully nonexistent, and we don't need
104  * the extra check.
105  */
106 static inline int user_mode(struct pt_regs *regs)
107 {
108 #ifdef CONFIG_X86_32
109 	return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >= USER_RPL;
110 #else
111 	return !!(regs->cs & 3);
112 #endif
113 }
114 
115 static inline int v8086_mode(struct pt_regs *regs)
116 {
117 #ifdef CONFIG_X86_32
118 	return (regs->flags & X86_VM_MASK);
119 #else
120 	return 0;	/* No V86 mode support in long mode */
121 #endif
122 }
123 
124 #ifdef CONFIG_X86_64
125 static inline bool user_64bit_mode(struct pt_regs *regs)
126 {
127 #ifndef CONFIG_PARAVIRT
128 	/*
129 	 * On non-paravirt systems, this is the only long mode CPL 3
130 	 * selector.  We do not allow long mode selectors in the LDT.
131 	 */
132 	return regs->cs == __USER_CS;
133 #else
134 	/* Headers are too twisted for this to go in paravirt.h. */
135 	return regs->cs == __USER_CS || regs->cs == pv_info.extra_user_64bit_cs;
136 #endif
137 }
138 
139 #define current_user_stack_pointer()	current_pt_regs()->sp
140 #define compat_user_stack_pointer()	current_pt_regs()->sp
141 #endif
142 
143 #ifdef CONFIG_X86_32
144 extern unsigned long kernel_stack_pointer(struct pt_regs *regs);
145 #else
146 static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
147 {
148 	return regs->sp;
149 }
150 #endif
151 
152 #define GET_IP(regs) ((regs)->ip)
153 #define GET_FP(regs) ((regs)->bp)
154 #define GET_USP(regs) ((regs)->sp)
155 
156 #include <asm-generic/ptrace.h>
157 
158 /* Query offset/name of register from its name/offset */
159 extern int regs_query_register_offset(const char *name);
160 extern const char *regs_query_register_name(unsigned int offset);
161 #define MAX_REG_OFFSET (offsetof(struct pt_regs, ss))
162 
163 /**
164  * regs_get_register() - get register value from its offset
165  * @regs:	pt_regs from which register value is gotten.
166  * @offset:	offset number of the register.
167  *
168  * regs_get_register returns the value of a register. The @offset is the
169  * offset of the register in struct pt_regs address which specified by @regs.
170  * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
171  */
172 static inline unsigned long regs_get_register(struct pt_regs *regs,
173 					      unsigned int offset)
174 {
175 	if (unlikely(offset > MAX_REG_OFFSET))
176 		return 0;
177 #ifdef CONFIG_X86_32
178 	/*
179 	 * Traps from the kernel do not save sp and ss.
180 	 * Use the helper function to retrieve sp.
181 	 */
182 	if (offset == offsetof(struct pt_regs, sp) &&
183 	    regs->cs == __KERNEL_CS)
184 		return kernel_stack_pointer(regs);
185 #endif
186 	return *(unsigned long *)((unsigned long)regs + offset);
187 }
188 
189 /**
190  * regs_within_kernel_stack() - check the address in the stack
191  * @regs:	pt_regs which contains kernel stack pointer.
192  * @addr:	address which is checked.
193  *
194  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
195  * If @addr is within the kernel stack, it returns true. If not, returns false.
196  */
197 static inline int regs_within_kernel_stack(struct pt_regs *regs,
198 					   unsigned long addr)
199 {
200 	return ((addr & ~(THREAD_SIZE - 1))  ==
201 		(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
202 }
203 
204 /**
205  * regs_get_kernel_stack_nth() - get Nth entry of the stack
206  * @regs:	pt_regs which contains kernel stack pointer.
207  * @n:		stack entry number.
208  *
209  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
210  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
211  * this returns 0.
212  */
213 static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
214 						      unsigned int n)
215 {
216 	unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
217 	addr += n;
218 	if (regs_within_kernel_stack(regs, (unsigned long)addr))
219 		return *addr;
220 	else
221 		return 0;
222 }
223 
224 #define arch_has_single_step()	(1)
225 #ifdef CONFIG_X86_DEBUGCTLMSR
226 #define arch_has_block_step()	(1)
227 #else
228 #define arch_has_block_step()	(boot_cpu_data.x86 >= 6)
229 #endif
230 
231 #define ARCH_HAS_USER_SINGLE_STEP_INFO
232 
233 /*
234  * When hitting ptrace_stop(), we cannot return using SYSRET because
235  * that does not restore the full CPU state, only a minimal set.  The
236  * ptracer can change arbitrary register values, which is usually okay
237  * because the usual ptrace stops run off the signal delivery path which
238  * forces IRET; however, ptrace_event() stops happen in arbitrary places
239  * in the kernel and don't force IRET path.
240  *
241  * So force IRET path after a ptrace stop.
242  */
243 #define arch_ptrace_stop_needed(code, info)				\
244 ({									\
245 	force_iret();							\
246 	false;								\
247 })
248 
249 struct user_desc;
250 extern int do_get_thread_area(struct task_struct *p, int idx,
251 			      struct user_desc __user *info);
252 extern int do_set_thread_area(struct task_struct *p, int idx,
253 			      struct user_desc __user *info, int can_allocate);
254 
255 #endif /* !__ASSEMBLY__ */
256 #endif /* _ASM_X86_PTRACE_H */
257