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 #include <asm/reg.h>
26 
27 #ifndef __ASSEMBLY__
28 struct pt_regs
29 {
30 	union {
31 		struct user_pt_regs user_regs;
32 		struct {
33 			unsigned long gpr[32];
34 			unsigned long nip;
35 			unsigned long msr;
36 			unsigned long orig_gpr3;
37 			unsigned long ctr;
38 			unsigned long link;
39 			unsigned long xer;
40 			unsigned long ccr;
41 #ifdef CONFIG_PPC64
42 			unsigned long softe;
43 #else
44 			unsigned long mq;
45 #endif
46 			unsigned long trap;
47 			union {
48 				unsigned long dar;
49 				unsigned long dear;
50 			};
51 			union {
52 				unsigned long dsisr;
53 				unsigned long esr;
54 			};
55 			unsigned long result;
56 		};
57 	};
58 #if defined(CONFIG_PPC64) || defined(CONFIG_PPC_KUAP)
59 	union {
60 		struct {
61 #ifdef CONFIG_PPC64
62 			unsigned long ppr;
63 			unsigned long exit_result;
64 #endif
65 			union {
66 #ifdef CONFIG_PPC_KUAP
67 				unsigned long kuap;
68 #endif
69 #ifdef CONFIG_PPC_PKEY
70 				unsigned long amr;
71 #endif
72 			};
73 #ifdef CONFIG_PPC_PKEY
74 			unsigned long iamr;
75 #endif
76 		};
77 		unsigned long __pad[4];	/* Maintain 16 byte interrupt stack alignment */
78 	};
79 #endif
80 #if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
81 	struct { /* Must be a multiple of 16 bytes */
82 		unsigned long mas0;
83 		unsigned long mas1;
84 		unsigned long mas2;
85 		unsigned long mas3;
86 		unsigned long mas6;
87 		unsigned long mas7;
88 		unsigned long srr0;
89 		unsigned long srr1;
90 		unsigned long csrr0;
91 		unsigned long csrr1;
92 		unsigned long dsrr0;
93 		unsigned long dsrr1;
94 	};
95 #endif
96 };
97 #endif
98 
99 
100 #define STACK_FRAME_WITH_PT_REGS (STACK_FRAME_OVERHEAD + sizeof(struct pt_regs))
101 
102 // Always displays as "REGS" in memory dumps
103 #ifdef CONFIG_CPU_BIG_ENDIAN
104 #define STACK_FRAME_REGS_MARKER	ASM_CONST(0x52454753)
105 #else
106 #define STACK_FRAME_REGS_MARKER	ASM_CONST(0x53474552)
107 #endif
108 
109 #ifdef __powerpc64__
110 
111 /*
112  * Size of redzone that userspace is allowed to use below the stack
113  * pointer.  This is 288 in the 64-bit big-endian ELF ABI, and 512 in
114  * the new ELFv2 little-endian ABI, so we allow the larger amount.
115  *
116  * For kernel code we allow a 288-byte redzone, in order to conserve
117  * kernel stack space; gcc currently only uses 288 bytes, and will
118  * hopefully allow explicit control of the redzone size in future.
119  */
120 #define USER_REDZONE_SIZE	512
121 #define KERNEL_REDZONE_SIZE	288
122 
123 #define STACK_FRAME_OVERHEAD	112	/* size of minimum stack frame */
124 #define STACK_FRAME_LR_SAVE	2	/* Location of LR in stack frame */
125 #define STACK_INT_FRAME_SIZE	(sizeof(struct pt_regs) + \
126 				 STACK_FRAME_OVERHEAD + KERNEL_REDZONE_SIZE)
127 #define STACK_FRAME_MARKER	12
128 
129 #ifdef CONFIG_PPC64_ELF_ABI_V2
130 #define STACK_FRAME_MIN_SIZE	32
131 #else
132 #define STACK_FRAME_MIN_SIZE	STACK_FRAME_OVERHEAD
133 #endif
134 
135 /* Size of dummy stack frame allocated when calling signal handler. */
136 #define __SIGNAL_FRAMESIZE	128
137 #define __SIGNAL_FRAMESIZE32	64
138 
139 #else /* __powerpc64__ */
140 
141 #define USER_REDZONE_SIZE	0
142 #define KERNEL_REDZONE_SIZE	0
143 #define STACK_FRAME_OVERHEAD	16	/* size of minimum stack frame */
144 #define STACK_FRAME_LR_SAVE	1	/* Location of LR in stack frame */
145 #define STACK_INT_FRAME_SIZE	(sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
146 #define STACK_FRAME_MARKER	2
147 #define STACK_FRAME_MIN_SIZE	STACK_FRAME_OVERHEAD
148 
149 /* Size of stack frame allocated when calling signal handler. */
150 #define __SIGNAL_FRAMESIZE	64
151 
152 #endif /* __powerpc64__ */
153 
154 #ifndef __ASSEMBLY__
155 #include <asm/paca.h>
156 
157 #ifdef CONFIG_SMP
158 extern unsigned long profile_pc(struct pt_regs *regs);
159 #else
160 #define profile_pc(regs) instruction_pointer(regs)
161 #endif
162 
163 long do_syscall_trace_enter(struct pt_regs *regs);
164 void do_syscall_trace_leave(struct pt_regs *regs);
165 
set_return_regs_changed(void)166 static inline void set_return_regs_changed(void)
167 {
168 #ifdef CONFIG_PPC_BOOK3S_64
169 	local_paca->hsrr_valid = 0;
170 	local_paca->srr_valid = 0;
171 #endif
172 }
173 
regs_set_return_ip(struct pt_regs * regs,unsigned long ip)174 static inline void regs_set_return_ip(struct pt_regs *regs, unsigned long ip)
175 {
176 	regs->nip = ip;
177 	set_return_regs_changed();
178 }
179 
regs_set_return_msr(struct pt_regs * regs,unsigned long msr)180 static inline void regs_set_return_msr(struct pt_regs *regs, unsigned long msr)
181 {
182 	regs->msr = msr;
183 	set_return_regs_changed();
184 }
185 
regs_add_return_ip(struct pt_regs * regs,long offset)186 static inline void regs_add_return_ip(struct pt_regs *regs, long offset)
187 {
188 	regs_set_return_ip(regs, regs->nip + offset);
189 }
190 
instruction_pointer(struct pt_regs * regs)191 static inline unsigned long instruction_pointer(struct pt_regs *regs)
192 {
193 	return regs->nip;
194 }
195 
instruction_pointer_set(struct pt_regs * regs,unsigned long val)196 static inline void instruction_pointer_set(struct pt_regs *regs,
197 		unsigned long val)
198 {
199 	regs_set_return_ip(regs, val);
200 }
201 
user_stack_pointer(struct pt_regs * regs)202 static inline unsigned long user_stack_pointer(struct pt_regs *regs)
203 {
204 	return regs->gpr[1];
205 }
206 
frame_pointer(struct pt_regs * regs)207 static inline unsigned long frame_pointer(struct pt_regs *regs)
208 {
209 	return 0;
210 }
211 
212 #define user_mode(regs) (((regs)->msr & MSR_PR) != 0)
213 
214 #define force_successful_syscall_return()   \
215 	do { \
216 		set_thread_flag(TIF_NOERROR); \
217 	} while(0)
218 
219 #define current_pt_regs() \
220 	((struct pt_regs *)((unsigned long)task_stack_page(current) + THREAD_SIZE) - 1)
221 
222 /*
223  * The 4 low bits (0xf) are available as flags to overload the trap word,
224  * because interrupt vectors have minimum alignment of 0x10. TRAP_FLAGS_MASK
225  * must cover the bits used as flags, including bit 0 which is used as the
226  * "norestart" bit.
227  */
228 #ifdef __powerpc64__
229 #define TRAP_FLAGS_MASK		0x1
230 #else
231 /*
232  * On 4xx we use bit 1 in the trap word to indicate whether the exception
233  * is a critical exception (1 means it is).
234  */
235 #define TRAP_FLAGS_MASK		0xf
236 #define IS_CRITICAL_EXC(regs)	(((regs)->trap & 2) != 0)
237 #define IS_MCHECK_EXC(regs)	(((regs)->trap & 4) != 0)
238 #define IS_DEBUG_EXC(regs)	(((regs)->trap & 8) != 0)
239 #endif /* __powerpc64__ */
240 #define TRAP(regs)		((regs)->trap & ~TRAP_FLAGS_MASK)
241 
set_trap(struct pt_regs * regs,unsigned long val)242 static __always_inline void set_trap(struct pt_regs *regs, unsigned long val)
243 {
244 	regs->trap = (regs->trap & TRAP_FLAGS_MASK) | (val & ~TRAP_FLAGS_MASK);
245 }
246 
trap_is_scv(struct pt_regs * regs)247 static inline bool trap_is_scv(struct pt_regs *regs)
248 {
249 	return (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && TRAP(regs) == 0x3000);
250 }
251 
trap_is_unsupported_scv(struct pt_regs * regs)252 static inline bool trap_is_unsupported_scv(struct pt_regs *regs)
253 {
254 	return IS_ENABLED(CONFIG_PPC_BOOK3S_64) && TRAP(regs) == 0x7ff0;
255 }
256 
trap_is_syscall(struct pt_regs * regs)257 static inline bool trap_is_syscall(struct pt_regs *regs)
258 {
259 	return (trap_is_scv(regs) || TRAP(regs) == 0xc00);
260 }
261 
trap_norestart(struct pt_regs * regs)262 static inline bool trap_norestart(struct pt_regs *regs)
263 {
264 	return regs->trap & 0x1;
265 }
266 
set_trap_norestart(struct pt_regs * regs)267 static __always_inline void set_trap_norestart(struct pt_regs *regs)
268 {
269 	regs->trap |= 0x1;
270 }
271 
272 #define kernel_stack_pointer(regs) ((regs)->gpr[1])
is_syscall_success(struct pt_regs * regs)273 static inline int is_syscall_success(struct pt_regs *regs)
274 {
275 	if (trap_is_scv(regs))
276 		return !IS_ERR_VALUE((unsigned long)regs->gpr[3]);
277 	else
278 		return !(regs->ccr & 0x10000000);
279 }
280 
regs_return_value(struct pt_regs * regs)281 static inline long regs_return_value(struct pt_regs *regs)
282 {
283 	if (trap_is_scv(regs))
284 		return regs->gpr[3];
285 
286 	if (is_syscall_success(regs))
287 		return regs->gpr[3];
288 	else
289 		return -regs->gpr[3];
290 }
291 
regs_set_return_value(struct pt_regs * regs,unsigned long rc)292 static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
293 {
294 	regs->gpr[3] = rc;
295 }
296 
cpu_has_msr_ri(void)297 static inline bool cpu_has_msr_ri(void)
298 {
299 	return !IS_ENABLED(CONFIG_BOOKE_OR_40x);
300 }
301 
regs_is_unrecoverable(struct pt_regs * regs)302 static inline bool regs_is_unrecoverable(struct pt_regs *regs)
303 {
304 	return unlikely(cpu_has_msr_ri() && !(regs->msr & MSR_RI));
305 }
306 
regs_set_recoverable(struct pt_regs * regs)307 static inline void regs_set_recoverable(struct pt_regs *regs)
308 {
309 	if (cpu_has_msr_ri())
310 		regs_set_return_msr(regs, regs->msr | MSR_RI);
311 }
312 
regs_set_unrecoverable(struct pt_regs * regs)313 static inline void regs_set_unrecoverable(struct pt_regs *regs)
314 {
315 	if (cpu_has_msr_ri())
316 		regs_set_return_msr(regs, regs->msr & ~MSR_RI);
317 }
318 
319 #define arch_has_single_step()	(1)
320 #define arch_has_block_step()	(true)
321 #define ARCH_HAS_USER_SINGLE_STEP_REPORT
322 
323 /*
324  * kprobe-based event tracer support
325  */
326 
327 #include <linux/stddef.h>
328 #include <linux/thread_info.h>
329 extern int regs_query_register_offset(const char *name);
330 extern const char *regs_query_register_name(unsigned int offset);
331 #define MAX_REG_OFFSET (offsetof(struct pt_regs, dsisr))
332 
333 /**
334  * regs_get_register() - get register value from its offset
335  * @regs:	   pt_regs from which register value is gotten
336  * @offset:    offset number of the register.
337  *
338  * regs_get_register returns the value of a register whose offset from @regs.
339  * The @offset is the offset of the register in struct pt_regs.
340  * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
341  */
regs_get_register(struct pt_regs * regs,unsigned int offset)342 static inline unsigned long regs_get_register(struct pt_regs *regs,
343 						unsigned int offset)
344 {
345 	if (unlikely(offset > MAX_REG_OFFSET))
346 		return 0;
347 	return *(unsigned long *)((unsigned long)regs + offset);
348 }
349 
350 /**
351  * regs_within_kernel_stack() - check the address in the stack
352  * @regs:      pt_regs which contains kernel stack pointer.
353  * @addr:      address which is checked.
354  *
355  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
356  * If @addr is within the kernel stack, it returns true. If not, returns false.
357  */
358 
regs_within_kernel_stack(struct pt_regs * regs,unsigned long addr)359 static inline bool regs_within_kernel_stack(struct pt_regs *regs,
360 						unsigned long addr)
361 {
362 	return ((addr & ~(THREAD_SIZE - 1))  ==
363 		(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
364 }
365 
366 /**
367  * regs_get_kernel_stack_nth() - get Nth entry of the stack
368  * @regs:	pt_regs which contains kernel stack pointer.
369  * @n:		stack entry number.
370  *
371  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
372  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
373  * this returns 0.
374  */
regs_get_kernel_stack_nth(struct pt_regs * regs,unsigned int n)375 static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
376 						      unsigned int n)
377 {
378 	unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
379 	addr += n;
380 	if (regs_within_kernel_stack(regs, (unsigned long)addr))
381 		return *addr;
382 	else
383 		return 0;
384 }
385 
386 #endif /* __ASSEMBLY__ */
387 
388 #ifndef __powerpc64__
389 /* We need PT_SOFTE defined at all time to avoid #ifdefs */
390 #define PT_SOFTE PT_MQ
391 #else /* __powerpc64__ */
392 #define PT_FPSCR32 (PT_FPR0 + 2*32 + 1)	/* each FP reg occupies 2 32-bit userspace slots */
393 #define PT_VR0_32 164	/* each Vector reg occupies 4 slots in 32-bit */
394 #define PT_VSCR_32 (PT_VR0 + 32*4 + 3)
395 #define PT_VRSAVE_32 (PT_VR0 + 33*4)
396 #define PT_VSR0_32 300 	/* each VSR reg occupies 4 slots in 32-bit */
397 #endif /* __powerpc64__ */
398 #endif /* _ASM_POWERPC_PTRACE_H */
399