1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Based on arch/arm/include/asm/ptrace.h
4 *
5 * Copyright (C) 1996-2003 Russell King
6 * Copyright (C) 2012 ARM Ltd.
7 */
8 #ifndef __ASM_PTRACE_H
9 #define __ASM_PTRACE_H
10
11 #include <asm/cpufeature.h>
12
13 #include <uapi/asm/ptrace.h>
14
15 /* Current Exception Level values, as contained in CurrentEL */
16 #define CurrentEL_EL1 (1 << 2)
17 #define CurrentEL_EL2 (2 << 2)
18
19 /*
20 * PMR values used to mask/unmask interrupts.
21 *
22 * GIC priority masking works as follows: if an IRQ's priority is a higher value
23 * than the value held in PMR, that IRQ is masked. Lowering the value of PMR
24 * means masking more IRQs (or at least that the same IRQs remain masked).
25 *
26 * To mask interrupts, we clear the most significant bit of PMR.
27 *
28 * Some code sections either automatically switch back to PSR.I or explicitly
29 * require to not use priority masking. If bit GIC_PRIO_PSR_I_SET is included
30 * in the priority mask, it indicates that PSR.I should be set and
31 * interrupt disabling temporarily does not rely on IRQ priorities.
32 */
33 #define GIC_PRIO_IRQON 0xe0
34 #define __GIC_PRIO_IRQOFF (GIC_PRIO_IRQON & ~0x80)
35 #define __GIC_PRIO_IRQOFF_NS 0xa0
36 #define GIC_PRIO_PSR_I_SET (1 << 4)
37
38 #define GIC_PRIO_IRQOFF \
39 ({ \
40 extern struct static_key_false gic_nonsecure_priorities;\
41 u8 __prio = __GIC_PRIO_IRQOFF; \
42 \
43 if (static_branch_unlikely(&gic_nonsecure_priorities)) \
44 __prio = __GIC_PRIO_IRQOFF_NS; \
45 \
46 __prio; \
47 })
48
49 /* Additional SPSR bits not exposed in the UABI */
50 #define PSR_MODE_THREAD_BIT (1 << 0)
51 #define PSR_IL_BIT (1 << 20)
52
53 /* AArch32-specific ptrace requests */
54 #define COMPAT_PTRACE_GETREGS 12
55 #define COMPAT_PTRACE_SETREGS 13
56 #define COMPAT_PTRACE_GET_THREAD_AREA 22
57 #define COMPAT_PTRACE_SET_SYSCALL 23
58 #define COMPAT_PTRACE_GETVFPREGS 27
59 #define COMPAT_PTRACE_SETVFPREGS 28
60 #define COMPAT_PTRACE_GETHBPREGS 29
61 #define COMPAT_PTRACE_SETHBPREGS 30
62
63 /* SPSR_ELx bits for exceptions taken from AArch32 */
64 #define PSR_AA32_MODE_MASK 0x0000001f
65 #define PSR_AA32_MODE_USR 0x00000010
66 #define PSR_AA32_MODE_FIQ 0x00000011
67 #define PSR_AA32_MODE_IRQ 0x00000012
68 #define PSR_AA32_MODE_SVC 0x00000013
69 #define PSR_AA32_MODE_ABT 0x00000017
70 #define PSR_AA32_MODE_HYP 0x0000001a
71 #define PSR_AA32_MODE_UND 0x0000001b
72 #define PSR_AA32_MODE_SYS 0x0000001f
73 #define PSR_AA32_T_BIT 0x00000020
74 #define PSR_AA32_F_BIT 0x00000040
75 #define PSR_AA32_I_BIT 0x00000080
76 #define PSR_AA32_A_BIT 0x00000100
77 #define PSR_AA32_E_BIT 0x00000200
78 #define PSR_AA32_PAN_BIT 0x00400000
79 #define PSR_AA32_SSBS_BIT 0x00800000
80 #define PSR_AA32_DIT_BIT 0x01000000
81 #define PSR_AA32_Q_BIT 0x08000000
82 #define PSR_AA32_V_BIT 0x10000000
83 #define PSR_AA32_C_BIT 0x20000000
84 #define PSR_AA32_Z_BIT 0x40000000
85 #define PSR_AA32_N_BIT 0x80000000
86 #define PSR_AA32_IT_MASK 0x0600fc00 /* If-Then execution state mask */
87 #define PSR_AA32_GE_MASK 0x000f0000
88
89 #ifdef CONFIG_CPU_BIG_ENDIAN
90 #define PSR_AA32_ENDSTATE PSR_AA32_E_BIT
91 #else
92 #define PSR_AA32_ENDSTATE 0
93 #endif
94
95 /* AArch32 CPSR bits, as seen in AArch32 */
96 #define COMPAT_PSR_DIT_BIT 0x00200000
97
98 /*
99 * These are 'magic' values for PTRACE_PEEKUSR that return info about where a
100 * process is located in memory.
101 */
102 #define COMPAT_PT_TEXT_ADDR 0x10000
103 #define COMPAT_PT_DATA_ADDR 0x10004
104 #define COMPAT_PT_TEXT_END_ADDR 0x10008
105
106 /*
107 * If pt_regs.syscallno == NO_SYSCALL, then the thread is not executing
108 * a syscall -- i.e., its most recent entry into the kernel from
109 * userspace was not via SVC, or otherwise a tracer cancelled the syscall.
110 *
111 * This must have the value -1, for ABI compatibility with ptrace etc.
112 */
113 #define NO_SYSCALL (-1)
114
115 #ifndef __ASSEMBLY__
116 #include <linux/bug.h>
117 #include <linux/types.h>
118
119 /* sizeof(struct user) for AArch32 */
120 #define COMPAT_USER_SZ 296
121
122 /* Architecturally defined mapping between AArch32 and AArch64 registers */
123 #define compat_usr(x) regs[(x)]
124 #define compat_fp regs[11]
125 #define compat_sp regs[13]
126 #define compat_lr regs[14]
127 #define compat_sp_hyp regs[15]
128 #define compat_lr_irq regs[16]
129 #define compat_sp_irq regs[17]
130 #define compat_lr_svc regs[18]
131 #define compat_sp_svc regs[19]
132 #define compat_lr_abt regs[20]
133 #define compat_sp_abt regs[21]
134 #define compat_lr_und regs[22]
135 #define compat_sp_und regs[23]
136 #define compat_r8_fiq regs[24]
137 #define compat_r9_fiq regs[25]
138 #define compat_r10_fiq regs[26]
139 #define compat_r11_fiq regs[27]
140 #define compat_r12_fiq regs[28]
141 #define compat_sp_fiq regs[29]
142 #define compat_lr_fiq regs[30]
143
compat_psr_to_pstate(const unsigned long psr)144 static inline unsigned long compat_psr_to_pstate(const unsigned long psr)
145 {
146 unsigned long pstate;
147
148 pstate = psr & ~COMPAT_PSR_DIT_BIT;
149
150 if (psr & COMPAT_PSR_DIT_BIT)
151 pstate |= PSR_AA32_DIT_BIT;
152
153 return pstate;
154 }
155
pstate_to_compat_psr(const unsigned long pstate)156 static inline unsigned long pstate_to_compat_psr(const unsigned long pstate)
157 {
158 unsigned long psr;
159
160 psr = pstate & ~PSR_AA32_DIT_BIT;
161
162 if (pstate & PSR_AA32_DIT_BIT)
163 psr |= COMPAT_PSR_DIT_BIT;
164
165 return psr;
166 }
167
168 /*
169 * This struct defines the way the registers are stored on the stack during an
170 * exception. Note that sizeof(struct pt_regs) has to be a multiple of 16 (for
171 * stack alignment). struct user_pt_regs must form a prefix of struct pt_regs.
172 */
173 struct pt_regs {
174 union {
175 struct user_pt_regs user_regs;
176 struct {
177 u64 regs[31];
178 u64 sp;
179 u64 pc;
180 u64 pstate;
181 };
182 };
183 u64 orig_x0;
184 #ifdef __AARCH64EB__
185 u32 unused2;
186 s32 syscallno;
187 #else
188 s32 syscallno;
189 u32 unused2;
190 #endif
191
192 u64 orig_addr_limit;
193 /* Only valid when ARM64_HAS_IRQ_PRIO_MASKING is enabled. */
194 u64 pmr_save;
195 u64 stackframe[2];
196
197 /* Only valid for some EL1 exceptions. */
198 u64 lockdep_hardirqs;
199 u64 exit_rcu;
200 };
201
in_syscall(struct pt_regs const * regs)202 static inline bool in_syscall(struct pt_regs const *regs)
203 {
204 return regs->syscallno != NO_SYSCALL;
205 }
206
forget_syscall(struct pt_regs * regs)207 static inline void forget_syscall(struct pt_regs *regs)
208 {
209 regs->syscallno = NO_SYSCALL;
210 }
211
212 #define MAX_REG_OFFSET offsetof(struct pt_regs, pstate)
213
214 #define arch_has_single_step() (1)
215
216 #ifdef CONFIG_COMPAT
217 #define compat_thumb_mode(regs) \
218 (((regs)->pstate & PSR_AA32_T_BIT))
219 #else
220 #define compat_thumb_mode(regs) (0)
221 #endif
222
223 #define user_mode(regs) \
224 (((regs)->pstate & PSR_MODE_MASK) == PSR_MODE_EL0t)
225
226 #define compat_user_mode(regs) \
227 (((regs)->pstate & (PSR_MODE32_BIT | PSR_MODE_MASK)) == \
228 (PSR_MODE32_BIT | PSR_MODE_EL0t))
229
230 #define processor_mode(regs) \
231 ((regs)->pstate & PSR_MODE_MASK)
232
233 #define irqs_priority_unmasked(regs) \
234 (system_uses_irq_prio_masking() ? \
235 (regs)->pmr_save == GIC_PRIO_IRQON : \
236 true)
237
238 #define interrupts_enabled(regs) \
239 (!((regs)->pstate & PSR_I_BIT) && irqs_priority_unmasked(regs))
240
241 #define fast_interrupts_enabled(regs) \
242 (!((regs)->pstate & PSR_F_BIT))
243
user_stack_pointer(struct pt_regs * regs)244 static inline unsigned long user_stack_pointer(struct pt_regs *regs)
245 {
246 if (compat_user_mode(regs))
247 return regs->compat_sp;
248 return regs->sp;
249 }
250
251 extern int regs_query_register_offset(const char *name);
252 extern unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
253 unsigned int n);
254
255 /**
256 * regs_get_register() - get register value from its offset
257 * @regs: pt_regs from which register value is gotten
258 * @offset: offset of the register.
259 *
260 * regs_get_register returns the value of a register whose offset from @regs.
261 * The @offset is the offset of the register in struct pt_regs.
262 * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
263 */
regs_get_register(struct pt_regs * regs,unsigned int offset)264 static inline u64 regs_get_register(struct pt_regs *regs, unsigned int offset)
265 {
266 u64 val = 0;
267
268 WARN_ON(offset & 7);
269
270 offset >>= 3;
271 switch (offset) {
272 case 0 ... 30:
273 val = regs->regs[offset];
274 break;
275 case offsetof(struct pt_regs, sp) >> 3:
276 val = regs->sp;
277 break;
278 case offsetof(struct pt_regs, pc) >> 3:
279 val = regs->pc;
280 break;
281 case offsetof(struct pt_regs, pstate) >> 3:
282 val = regs->pstate;
283 break;
284 default:
285 val = 0;
286 }
287
288 return val;
289 }
290
291 /*
292 * Read a register given an architectural register index r.
293 * This handles the common case where 31 means XZR, not SP.
294 */
pt_regs_read_reg(const struct pt_regs * regs,int r)295 static inline unsigned long pt_regs_read_reg(const struct pt_regs *regs, int r)
296 {
297 return (r == 31) ? 0 : regs->regs[r];
298 }
299
300 /*
301 * Write a register given an architectural register index r.
302 * This handles the common case where 31 means XZR, not SP.
303 */
pt_regs_write_reg(struct pt_regs * regs,int r,unsigned long val)304 static inline void pt_regs_write_reg(struct pt_regs *regs, int r,
305 unsigned long val)
306 {
307 if (r != 31)
308 regs->regs[r] = val;
309 }
310
311 /* Valid only for Kernel mode traps. */
kernel_stack_pointer(struct pt_regs * regs)312 static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
313 {
314 return regs->sp;
315 }
316
regs_return_value(struct pt_regs * regs)317 static inline unsigned long regs_return_value(struct pt_regs *regs)
318 {
319 unsigned long val = regs->regs[0];
320
321 /*
322 * Audit currently uses regs_return_value() instead of
323 * syscall_get_return_value(). Apply the same sign-extension here until
324 * audit is updated to use syscall_get_return_value().
325 */
326 if (compat_user_mode(regs))
327 val = sign_extend64(val, 31);
328
329 return val;
330 }
331
regs_set_return_value(struct pt_regs * regs,unsigned long rc)332 static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
333 {
334 regs->regs[0] = rc;
335 }
336
337 /**
338 * regs_get_kernel_argument() - get Nth function argument in kernel
339 * @regs: pt_regs of that context
340 * @n: function argument number (start from 0)
341 *
342 * regs_get_argument() returns @n th argument of the function call.
343 *
344 * Note that this chooses the most likely register mapping. In very rare
345 * cases this may not return correct data, for example, if one of the
346 * function parameters is 16 bytes or bigger. In such cases, we cannot
347 * get access the parameter correctly and the register assignment of
348 * subsequent parameters will be shifted.
349 */
regs_get_kernel_argument(struct pt_regs * regs,unsigned int n)350 static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs,
351 unsigned int n)
352 {
353 #define NR_REG_ARGUMENTS 8
354 if (n < NR_REG_ARGUMENTS)
355 return pt_regs_read_reg(regs, n);
356 return 0;
357 }
358
359 /* We must avoid circular header include via sched.h */
360 struct task_struct;
361 int valid_user_regs(struct user_pt_regs *regs, struct task_struct *task);
362
instruction_pointer(struct pt_regs * regs)363 static inline unsigned long instruction_pointer(struct pt_regs *regs)
364 {
365 return regs->pc;
366 }
instruction_pointer_set(struct pt_regs * regs,unsigned long val)367 static inline void instruction_pointer_set(struct pt_regs *regs,
368 unsigned long val)
369 {
370 regs->pc = val;
371 }
372
frame_pointer(struct pt_regs * regs)373 static inline unsigned long frame_pointer(struct pt_regs *regs)
374 {
375 return regs->regs[29];
376 }
377
378 #define procedure_link_pointer(regs) ((regs)->regs[30])
379
procedure_link_pointer_set(struct pt_regs * regs,unsigned long val)380 static inline void procedure_link_pointer_set(struct pt_regs *regs,
381 unsigned long val)
382 {
383 procedure_link_pointer(regs) = val;
384 }
385
386 extern unsigned long profile_pc(struct pt_regs *regs);
387
388 #endif /* __ASSEMBLY__ */
389 #endif
390