xref: /linux/arch/powerpc/include/asm/ptrace.h (revision a3cbcadfdfc330c28a45f06e8f92fd1d59aafa19)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * Copyright (C) 2001 PPC64 Team, IBM Corp
4  *
5  * This struct defines the way the registers are stored on the
6  * kernel stack during a system call or other kernel entry.
7  *
8  * this should only contain volatile regs
9  * since we can keep non-volatile in the thread_struct
10  * should set this up when only volatiles are saved
11  * by intr code.
12  *
13  * Since this is going on the stack, *CARE MUST BE TAKEN* to insure
14  * that the overall structure is a multiple of 16 bytes in length.
15  *
16  * Note that the offsets of the fields in this struct correspond with
17  * the PT_* values below.  This simplifies arch/powerpc/kernel/ptrace.c.
18  */
19 #ifndef _ASM_POWERPC_PTRACE_H
20 #define _ASM_POWERPC_PTRACE_H
21 
22 #include <linux/err.h>
23 #include <uapi/asm/ptrace.h>
24 #include <asm/asm-const.h>
25 
26 #ifndef __ASSEMBLY__
27 struct pt_regs
28 {
29 	union {
30 		struct user_pt_regs user_regs;
31 		struct {
32 			unsigned long gpr[32];
33 			unsigned long nip;
34 			unsigned long msr;
35 			unsigned long orig_gpr3;
36 			unsigned long ctr;
37 			unsigned long link;
38 			unsigned long xer;
39 			unsigned long ccr;
40 #ifdef CONFIG_PPC64
41 			unsigned long softe;
42 #else
43 			unsigned long mq;
44 #endif
45 			unsigned long trap;
46 			unsigned long dar;
47 			unsigned long dsisr;
48 			unsigned long result;
49 		};
50 	};
51 #if defined(CONFIG_PPC64) || defined(CONFIG_PPC_KUAP)
52 	union {
53 		struct {
54 #ifdef CONFIG_PPC64
55 			unsigned long ppr;
56 			unsigned long exit_result;
57 #endif
58 			union {
59 #ifdef CONFIG_PPC_KUAP
60 				unsigned long kuap;
61 #endif
62 #ifdef CONFIG_PPC_PKEY
63 				unsigned long amr;
64 #endif
65 			};
66 #ifdef CONFIG_PPC_PKEY
67 			unsigned long iamr;
68 #endif
69 		};
70 		unsigned long __pad[4];	/* Maintain 16 byte interrupt stack alignment */
71 	};
72 #endif
73 };
74 #endif
75 
76 
77 #define STACK_FRAME_WITH_PT_REGS (STACK_FRAME_OVERHEAD + sizeof(struct pt_regs))
78 
79 #ifdef __powerpc64__
80 
81 /*
82  * Size of redzone that userspace is allowed to use below the stack
83  * pointer.  This is 288 in the 64-bit big-endian ELF ABI, and 512 in
84  * the new ELFv2 little-endian ABI, so we allow the larger amount.
85  *
86  * For kernel code we allow a 288-byte redzone, in order to conserve
87  * kernel stack space; gcc currently only uses 288 bytes, and will
88  * hopefully allow explicit control of the redzone size in future.
89  */
90 #define USER_REDZONE_SIZE	512
91 #define KERNEL_REDZONE_SIZE	288
92 
93 #define STACK_FRAME_OVERHEAD	112	/* size of minimum stack frame */
94 #define STACK_FRAME_LR_SAVE	2	/* Location of LR in stack frame */
95 #define STACK_FRAME_REGS_MARKER	ASM_CONST(0x7265677368657265)
96 #define STACK_INT_FRAME_SIZE	(sizeof(struct pt_regs) + \
97 				 STACK_FRAME_OVERHEAD + KERNEL_REDZONE_SIZE)
98 #define STACK_FRAME_MARKER	12
99 
100 #ifdef PPC64_ELF_ABI_v2
101 #define STACK_FRAME_MIN_SIZE	32
102 #else
103 #define STACK_FRAME_MIN_SIZE	STACK_FRAME_OVERHEAD
104 #endif
105 
106 /* Size of dummy stack frame allocated when calling signal handler. */
107 #define __SIGNAL_FRAMESIZE	128
108 #define __SIGNAL_FRAMESIZE32	64
109 
110 #else /* __powerpc64__ */
111 
112 #define USER_REDZONE_SIZE	0
113 #define KERNEL_REDZONE_SIZE	0
114 #define STACK_FRAME_OVERHEAD	16	/* size of minimum stack frame */
115 #define STACK_FRAME_LR_SAVE	1	/* Location of LR in stack frame */
116 #define STACK_FRAME_REGS_MARKER	ASM_CONST(0x72656773)
117 #define STACK_INT_FRAME_SIZE	(sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
118 #define STACK_FRAME_MARKER	2
119 #define STACK_FRAME_MIN_SIZE	STACK_FRAME_OVERHEAD
120 
121 /* Size of stack frame allocated when calling signal handler. */
122 #define __SIGNAL_FRAMESIZE	64
123 
124 #endif /* __powerpc64__ */
125 
126 #ifndef __ASSEMBLY__
127 #include <asm/paca.h>
128 
129 #ifdef CONFIG_SMP
130 extern unsigned long profile_pc(struct pt_regs *regs);
131 #else
132 #define profile_pc(regs) instruction_pointer(regs)
133 #endif
134 
135 long do_syscall_trace_enter(struct pt_regs *regs);
136 void do_syscall_trace_leave(struct pt_regs *regs);
137 
138 static inline void set_return_regs_changed(void)
139 {
140 #ifdef CONFIG_PPC_BOOK3S_64
141 	local_paca->hsrr_valid = 0;
142 	local_paca->srr_valid = 0;
143 #endif
144 }
145 
146 static inline void regs_set_return_ip(struct pt_regs *regs, unsigned long ip)
147 {
148 	regs->nip = ip;
149 	set_return_regs_changed();
150 }
151 
152 static inline void regs_set_return_msr(struct pt_regs *regs, unsigned long msr)
153 {
154 	regs->msr = msr;
155 	set_return_regs_changed();
156 }
157 
158 static inline void regs_add_return_ip(struct pt_regs *regs, long offset)
159 {
160 	regs_set_return_ip(regs, regs->nip + offset);
161 }
162 
163 static inline unsigned long instruction_pointer(struct pt_regs *regs)
164 {
165 	return regs->nip;
166 }
167 
168 static inline void instruction_pointer_set(struct pt_regs *regs,
169 		unsigned long val)
170 {
171 	regs_set_return_ip(regs, val);
172 }
173 
174 static inline unsigned long user_stack_pointer(struct pt_regs *regs)
175 {
176 	return regs->gpr[1];
177 }
178 
179 static inline unsigned long frame_pointer(struct pt_regs *regs)
180 {
181 	return 0;
182 }
183 
184 #ifdef __powerpc64__
185 #define user_mode(regs) ((((regs)->msr) >> MSR_PR_LG) & 0x1)
186 #else
187 #define user_mode(regs) (((regs)->msr & MSR_PR) != 0)
188 #endif
189 
190 #define force_successful_syscall_return()   \
191 	do { \
192 		set_thread_flag(TIF_NOERROR); \
193 	} while(0)
194 
195 #define current_pt_regs() \
196 	((struct pt_regs *)((unsigned long)task_stack_page(current) + THREAD_SIZE) - 1)
197 
198 /*
199  * The 4 low bits (0xf) are available as flags to overload the trap word,
200  * because interrupt vectors have minimum alignment of 0x10. TRAP_FLAGS_MASK
201  * must cover the bits used as flags, including bit 0 which is used as the
202  * "norestart" bit.
203  */
204 #ifdef __powerpc64__
205 #define TRAP_FLAGS_MASK		0x1
206 #else
207 /*
208  * On 4xx we use bit 1 in the trap word to indicate whether the exception
209  * is a critical exception (1 means it is).
210  */
211 #define TRAP_FLAGS_MASK		0xf
212 #define IS_CRITICAL_EXC(regs)	(((regs)->trap & 2) != 0)
213 #define IS_MCHECK_EXC(regs)	(((regs)->trap & 4) != 0)
214 #define IS_DEBUG_EXC(regs)	(((regs)->trap & 8) != 0)
215 #endif /* __powerpc64__ */
216 #define TRAP(regs)		((regs)->trap & ~TRAP_FLAGS_MASK)
217 
218 static __always_inline void set_trap(struct pt_regs *regs, unsigned long val)
219 {
220 	regs->trap = (regs->trap & TRAP_FLAGS_MASK) | (val & ~TRAP_FLAGS_MASK);
221 }
222 
223 static inline bool trap_is_scv(struct pt_regs *regs)
224 {
225 	return (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && TRAP(regs) == 0x3000);
226 }
227 
228 static inline bool trap_is_unsupported_scv(struct pt_regs *regs)
229 {
230 	return IS_ENABLED(CONFIG_PPC_BOOK3S_64) && TRAP(regs) == 0x7ff0;
231 }
232 
233 static inline bool trap_is_syscall(struct pt_regs *regs)
234 {
235 	return (trap_is_scv(regs) || TRAP(regs) == 0xc00);
236 }
237 
238 static inline bool trap_norestart(struct pt_regs *regs)
239 {
240 	return regs->trap & 0x1;
241 }
242 
243 static __always_inline void set_trap_norestart(struct pt_regs *regs)
244 {
245 	regs->trap |= 0x1;
246 }
247 
248 #define kernel_stack_pointer(regs) ((regs)->gpr[1])
249 static inline int is_syscall_success(struct pt_regs *regs)
250 {
251 	if (trap_is_scv(regs))
252 		return !IS_ERR_VALUE((unsigned long)regs->gpr[3]);
253 	else
254 		return !(regs->ccr & 0x10000000);
255 }
256 
257 static inline long regs_return_value(struct pt_regs *regs)
258 {
259 	if (trap_is_scv(regs))
260 		return regs->gpr[3];
261 
262 	if (is_syscall_success(regs))
263 		return regs->gpr[3];
264 	else
265 		return -regs->gpr[3];
266 }
267 
268 static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
269 {
270 	regs->gpr[3] = rc;
271 }
272 
273 #define arch_has_single_step()	(1)
274 #define arch_has_block_step()	(true)
275 #define ARCH_HAS_USER_SINGLE_STEP_REPORT
276 
277 /*
278  * kprobe-based event tracer support
279  */
280 
281 #include <linux/stddef.h>
282 #include <linux/thread_info.h>
283 extern int regs_query_register_offset(const char *name);
284 extern const char *regs_query_register_name(unsigned int offset);
285 #define MAX_REG_OFFSET (offsetof(struct pt_regs, dsisr))
286 
287 /**
288  * regs_get_register() - get register value from its offset
289  * @regs:	   pt_regs from which register value is gotten
290  * @offset:    offset number of the register.
291  *
292  * regs_get_register returns the value of a register whose offset from @regs.
293  * The @offset is the offset of the register in struct pt_regs.
294  * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
295  */
296 static inline unsigned long regs_get_register(struct pt_regs *regs,
297 						unsigned int offset)
298 {
299 	if (unlikely(offset > MAX_REG_OFFSET))
300 		return 0;
301 	return *(unsigned long *)((unsigned long)regs + offset);
302 }
303 
304 /**
305  * regs_within_kernel_stack() - check the address in the stack
306  * @regs:      pt_regs which contains kernel stack pointer.
307  * @addr:      address which is checked.
308  *
309  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
310  * If @addr is within the kernel stack, it returns true. If not, returns false.
311  */
312 
313 static inline bool regs_within_kernel_stack(struct pt_regs *regs,
314 						unsigned long addr)
315 {
316 	return ((addr & ~(THREAD_SIZE - 1))  ==
317 		(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
318 }
319 
320 /**
321  * regs_get_kernel_stack_nth() - get Nth entry of the stack
322  * @regs:	pt_regs which contains kernel stack pointer.
323  * @n:		stack entry number.
324  *
325  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
326  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
327  * this returns 0.
328  */
329 static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
330 						      unsigned int n)
331 {
332 	unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
333 	addr += n;
334 	if (regs_within_kernel_stack(regs, (unsigned long)addr))
335 		return *addr;
336 	else
337 		return 0;
338 }
339 
340 #endif /* __ASSEMBLY__ */
341 
342 #ifndef __powerpc64__
343 /* We need PT_SOFTE defined at all time to avoid #ifdefs */
344 #define PT_SOFTE PT_MQ
345 #else /* __powerpc64__ */
346 #define PT_FPSCR32 (PT_FPR0 + 2*32 + 1)	/* each FP reg occupies 2 32-bit userspace slots */
347 #define PT_VR0_32 164	/* each Vector reg occupies 4 slots in 32-bit */
348 #define PT_VSCR_32 (PT_VR0 + 32*4 + 3)
349 #define PT_VRSAVE_32 (PT_VR0 + 33*4)
350 #define PT_VSR0_32 300 	/* each VSR reg occupies 4 slots in 32-bit */
351 #endif /* __powerpc64__ */
352 #endif /* _ASM_POWERPC_PTRACE_H */
353