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60ffc30d CM |
1 | /* |
2 | * Low-level exception handling code | |
3 | * | |
4 | * Copyright (C) 2012 ARM Ltd. | |
5 | * Authors: Catalin Marinas <catalin.marinas@arm.com> | |
6 | * Will Deacon <will.deacon@arm.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
19 | */ | |
20 | ||
21 | #include <linux/init.h> | |
22 | #include <linux/linkage.h> | |
23 | ||
24 | #include <asm/assembler.h> | |
25 | #include <asm/asm-offsets.h> | |
26 | #include <asm/errno.h> | |
5c1ce6f7 | 27 | #include <asm/esr.h> |
60ffc30d CM |
28 | #include <asm/thread_info.h> |
29 | #include <asm/unistd.h> | |
f3d447a9 | 30 | #include <asm/unistd32.h> |
60ffc30d CM |
31 | |
32 | /* | |
33 | * Bad Abort numbers | |
34 | *----------------- | |
35 | */ | |
36 | #define BAD_SYNC 0 | |
37 | #define BAD_IRQ 1 | |
38 | #define BAD_FIQ 2 | |
39 | #define BAD_ERROR 3 | |
40 | ||
41 | .macro kernel_entry, el, regsize = 64 | |
42 | sub sp, sp, #S_FRAME_SIZE - S_LR // room for LR, SP, SPSR, ELR | |
43 | .if \regsize == 32 | |
44 | mov w0, w0 // zero upper 32 bits of x0 | |
45 | .endif | |
46 | push x28, x29 | |
47 | push x26, x27 | |
48 | push x24, x25 | |
49 | push x22, x23 | |
50 | push x20, x21 | |
51 | push x18, x19 | |
52 | push x16, x17 | |
53 | push x14, x15 | |
54 | push x12, x13 | |
55 | push x10, x11 | |
56 | push x8, x9 | |
57 | push x6, x7 | |
58 | push x4, x5 | |
59 | push x2, x3 | |
60 | push x0, x1 | |
61 | .if \el == 0 | |
62 | mrs x21, sp_el0 | |
2a283070 WD |
63 | get_thread_info tsk // Ensure MDSCR_EL1.SS is clear, |
64 | ldr x19, [tsk, #TI_FLAGS] // since we can unmask debug | |
65 | disable_step_tsk x19, x20 // exceptions when scheduling. | |
60ffc30d CM |
66 | .else |
67 | add x21, sp, #S_FRAME_SIZE | |
68 | .endif | |
69 | mrs x22, elr_el1 | |
70 | mrs x23, spsr_el1 | |
71 | stp lr, x21, [sp, #S_LR] | |
72 | stp x22, x23, [sp, #S_PC] | |
73 | ||
74 | /* | |
75 | * Set syscallno to -1 by default (overridden later if real syscall). | |
76 | */ | |
77 | .if \el == 0 | |
78 | mvn x21, xzr | |
79 | str x21, [sp, #S_SYSCALLNO] | |
80 | .endif | |
81 | ||
82 | /* | |
83 | * Registers that may be useful after this macro is invoked: | |
84 | * | |
85 | * x21 - aborted SP | |
86 | * x22 - aborted PC | |
87 | * x23 - aborted PSTATE | |
88 | */ | |
89 | .endm | |
90 | ||
91 | .macro kernel_exit, el, ret = 0 | |
92 | ldp x21, x22, [sp, #S_PC] // load ELR, SPSR | |
93 | .if \el == 0 | |
94 | ldr x23, [sp, #S_SP] // load return stack pointer | |
95 | .endif | |
96 | .if \ret | |
97 | ldr x1, [sp, #S_X1] // preserve x0 (syscall return) | |
98 | add sp, sp, S_X2 | |
99 | .else | |
100 | pop x0, x1 | |
101 | .endif | |
102 | pop x2, x3 // load the rest of the registers | |
103 | pop x4, x5 | |
104 | pop x6, x7 | |
105 | pop x8, x9 | |
106 | msr elr_el1, x21 // set up the return data | |
107 | msr spsr_el1, x22 | |
108 | .if \el == 0 | |
109 | msr sp_el0, x23 | |
110 | .endif | |
111 | pop x10, x11 | |
112 | pop x12, x13 | |
113 | pop x14, x15 | |
114 | pop x16, x17 | |
115 | pop x18, x19 | |
116 | pop x20, x21 | |
117 | pop x22, x23 | |
118 | pop x24, x25 | |
119 | pop x26, x27 | |
120 | pop x28, x29 | |
121 | ldr lr, [sp], #S_FRAME_SIZE - S_LR // load LR and restore SP | |
122 | eret // return to kernel | |
123 | .endm | |
124 | ||
125 | .macro get_thread_info, rd | |
126 | mov \rd, sp | |
845ad05e | 127 | and \rd, \rd, #~(THREAD_SIZE - 1) // top of stack |
60ffc30d CM |
128 | .endm |
129 | ||
130 | /* | |
131 | * These are the registers used in the syscall handler, and allow us to | |
132 | * have in theory up to 7 arguments to a function - x0 to x6. | |
133 | * | |
134 | * x7 is reserved for the system call number in 32-bit mode. | |
135 | */ | |
136 | sc_nr .req x25 // number of system calls | |
137 | scno .req x26 // syscall number | |
138 | stbl .req x27 // syscall table pointer | |
139 | tsk .req x28 // current thread_info | |
140 | ||
141 | /* | |
142 | * Interrupt handling. | |
143 | */ | |
144 | .macro irq_handler | |
145 | ldr x1, handle_arch_irq | |
146 | mov x0, sp | |
147 | blr x1 | |
148 | .endm | |
149 | ||
150 | .text | |
151 | ||
152 | /* | |
153 | * Exception vectors. | |
154 | */ | |
60ffc30d CM |
155 | |
156 | .align 11 | |
157 | ENTRY(vectors) | |
158 | ventry el1_sync_invalid // Synchronous EL1t | |
159 | ventry el1_irq_invalid // IRQ EL1t | |
160 | ventry el1_fiq_invalid // FIQ EL1t | |
161 | ventry el1_error_invalid // Error EL1t | |
162 | ||
163 | ventry el1_sync // Synchronous EL1h | |
164 | ventry el1_irq // IRQ EL1h | |
165 | ventry el1_fiq_invalid // FIQ EL1h | |
166 | ventry el1_error_invalid // Error EL1h | |
167 | ||
168 | ventry el0_sync // Synchronous 64-bit EL0 | |
169 | ventry el0_irq // IRQ 64-bit EL0 | |
170 | ventry el0_fiq_invalid // FIQ 64-bit EL0 | |
171 | ventry el0_error_invalid // Error 64-bit EL0 | |
172 | ||
173 | #ifdef CONFIG_COMPAT | |
174 | ventry el0_sync_compat // Synchronous 32-bit EL0 | |
175 | ventry el0_irq_compat // IRQ 32-bit EL0 | |
176 | ventry el0_fiq_invalid_compat // FIQ 32-bit EL0 | |
177 | ventry el0_error_invalid_compat // Error 32-bit EL0 | |
178 | #else | |
179 | ventry el0_sync_invalid // Synchronous 32-bit EL0 | |
180 | ventry el0_irq_invalid // IRQ 32-bit EL0 | |
181 | ventry el0_fiq_invalid // FIQ 32-bit EL0 | |
182 | ventry el0_error_invalid // Error 32-bit EL0 | |
183 | #endif | |
184 | END(vectors) | |
185 | ||
186 | /* | |
187 | * Invalid mode handlers | |
188 | */ | |
189 | .macro inv_entry, el, reason, regsize = 64 | |
190 | kernel_entry el, \regsize | |
191 | mov x0, sp | |
192 | mov x1, #\reason | |
193 | mrs x2, esr_el1 | |
194 | b bad_mode | |
195 | .endm | |
196 | ||
197 | el0_sync_invalid: | |
198 | inv_entry 0, BAD_SYNC | |
199 | ENDPROC(el0_sync_invalid) | |
200 | ||
201 | el0_irq_invalid: | |
202 | inv_entry 0, BAD_IRQ | |
203 | ENDPROC(el0_irq_invalid) | |
204 | ||
205 | el0_fiq_invalid: | |
206 | inv_entry 0, BAD_FIQ | |
207 | ENDPROC(el0_fiq_invalid) | |
208 | ||
209 | el0_error_invalid: | |
210 | inv_entry 0, BAD_ERROR | |
211 | ENDPROC(el0_error_invalid) | |
212 | ||
213 | #ifdef CONFIG_COMPAT | |
214 | el0_fiq_invalid_compat: | |
215 | inv_entry 0, BAD_FIQ, 32 | |
216 | ENDPROC(el0_fiq_invalid_compat) | |
217 | ||
218 | el0_error_invalid_compat: | |
219 | inv_entry 0, BAD_ERROR, 32 | |
220 | ENDPROC(el0_error_invalid_compat) | |
221 | #endif | |
222 | ||
223 | el1_sync_invalid: | |
224 | inv_entry 1, BAD_SYNC | |
225 | ENDPROC(el1_sync_invalid) | |
226 | ||
227 | el1_irq_invalid: | |
228 | inv_entry 1, BAD_IRQ | |
229 | ENDPROC(el1_irq_invalid) | |
230 | ||
231 | el1_fiq_invalid: | |
232 | inv_entry 1, BAD_FIQ | |
233 | ENDPROC(el1_fiq_invalid) | |
234 | ||
235 | el1_error_invalid: | |
236 | inv_entry 1, BAD_ERROR | |
237 | ENDPROC(el1_error_invalid) | |
238 | ||
239 | /* | |
240 | * EL1 mode handlers. | |
241 | */ | |
242 | .align 6 | |
243 | el1_sync: | |
244 | kernel_entry 1 | |
245 | mrs x1, esr_el1 // read the syndrome register | |
5c1ce6f7 MZ |
246 | lsr x24, x1, #ESR_EL1_EC_SHIFT // exception class |
247 | cmp x24, #ESR_EL1_EC_DABT_EL1 // data abort in EL1 | |
60ffc30d | 248 | b.eq el1_da |
5c1ce6f7 | 249 | cmp x24, #ESR_EL1_EC_SYS64 // configurable trap |
60ffc30d | 250 | b.eq el1_undef |
5c1ce6f7 | 251 | cmp x24, #ESR_EL1_EC_SP_ALIGN // stack alignment exception |
60ffc30d | 252 | b.eq el1_sp_pc |
5c1ce6f7 | 253 | cmp x24, #ESR_EL1_EC_PC_ALIGN // pc alignment exception |
60ffc30d | 254 | b.eq el1_sp_pc |
5c1ce6f7 | 255 | cmp x24, #ESR_EL1_EC_UNKNOWN // unknown exception in EL1 |
60ffc30d | 256 | b.eq el1_undef |
5c1ce6f7 | 257 | cmp x24, #ESR_EL1_EC_BREAKPT_EL1 // debug exception in EL1 |
60ffc30d CM |
258 | b.ge el1_dbg |
259 | b el1_inv | |
260 | el1_da: | |
261 | /* | |
262 | * Data abort handling | |
263 | */ | |
264 | mrs x0, far_el1 | |
2a283070 | 265 | enable_dbg |
60ffc30d CM |
266 | // re-enable interrupts if they were enabled in the aborted context |
267 | tbnz x23, #7, 1f // PSR_I_BIT | |
268 | enable_irq | |
269 | 1: | |
270 | mov x2, sp // struct pt_regs | |
271 | bl do_mem_abort | |
272 | ||
273 | // disable interrupts before pulling preserved data off the stack | |
274 | disable_irq | |
275 | kernel_exit 1 | |
276 | el1_sp_pc: | |
277 | /* | |
278 | * Stack or PC alignment exception handling | |
279 | */ | |
280 | mrs x0, far_el1 | |
2a283070 | 281 | enable_dbg |
60ffc30d CM |
282 | mov x1, x25 |
283 | mov x2, sp | |
284 | b do_sp_pc_abort | |
285 | el1_undef: | |
286 | /* | |
287 | * Undefined instruction | |
288 | */ | |
2a283070 | 289 | enable_dbg |
60ffc30d CM |
290 | mov x0, sp |
291 | b do_undefinstr | |
292 | el1_dbg: | |
293 | /* | |
294 | * Debug exception handling | |
295 | */ | |
ee6214ce SP |
296 | cmp x24, #ESR_EL1_EC_BRK64 // if BRK64 |
297 | cinc x24, x24, eq // set bit '0' | |
60ffc30d CM |
298 | tbz x24, #0, el1_inv // EL1 only |
299 | mrs x0, far_el1 | |
300 | mov x2, sp // struct pt_regs | |
301 | bl do_debug_exception | |
2a283070 | 302 | enable_dbg |
60ffc30d CM |
303 | kernel_exit 1 |
304 | el1_inv: | |
305 | // TODO: add support for undefined instructions in kernel mode | |
2a283070 | 306 | enable_dbg |
60ffc30d CM |
307 | mov x0, sp |
308 | mov x1, #BAD_SYNC | |
309 | mrs x2, esr_el1 | |
310 | b bad_mode | |
311 | ENDPROC(el1_sync) | |
312 | ||
313 | .align 6 | |
314 | el1_irq: | |
315 | kernel_entry 1 | |
2a283070 | 316 | enable_dbg |
60ffc30d CM |
317 | #ifdef CONFIG_TRACE_IRQFLAGS |
318 | bl trace_hardirqs_off | |
319 | #endif | |
64681787 | 320 | |
60ffc30d | 321 | irq_handler |
64681787 | 322 | |
60ffc30d | 323 | #ifdef CONFIG_PREEMPT |
64681787 | 324 | get_thread_info tsk |
883c0573 | 325 | ldr w24, [tsk, #TI_PREEMPT] // get preempt count |
717321fc | 326 | cbnz w24, 1f // preempt count != 0 |
60ffc30d CM |
327 | ldr x0, [tsk, #TI_FLAGS] // get flags |
328 | tbz x0, #TIF_NEED_RESCHED, 1f // needs rescheduling? | |
329 | bl el1_preempt | |
330 | 1: | |
331 | #endif | |
332 | #ifdef CONFIG_TRACE_IRQFLAGS | |
333 | bl trace_hardirqs_on | |
334 | #endif | |
335 | kernel_exit 1 | |
336 | ENDPROC(el1_irq) | |
337 | ||
338 | #ifdef CONFIG_PREEMPT | |
339 | el1_preempt: | |
340 | mov x24, lr | |
2a283070 | 341 | 1: bl preempt_schedule_irq // irq en/disable is done inside |
60ffc30d CM |
342 | ldr x0, [tsk, #TI_FLAGS] // get new tasks TI_FLAGS |
343 | tbnz x0, #TIF_NEED_RESCHED, 1b // needs rescheduling? | |
344 | ret x24 | |
345 | #endif | |
346 | ||
347 | /* | |
348 | * EL0 mode handlers. | |
349 | */ | |
350 | .align 6 | |
351 | el0_sync: | |
352 | kernel_entry 0 | |
353 | mrs x25, esr_el1 // read the syndrome register | |
5c1ce6f7 MZ |
354 | lsr x24, x25, #ESR_EL1_EC_SHIFT // exception class |
355 | cmp x24, #ESR_EL1_EC_SVC64 // SVC in 64-bit state | |
60ffc30d | 356 | b.eq el0_svc |
2a283070 | 357 | adr lr, ret_to_user |
5c1ce6f7 | 358 | cmp x24, #ESR_EL1_EC_DABT_EL0 // data abort in EL0 |
60ffc30d | 359 | b.eq el0_da |
5c1ce6f7 | 360 | cmp x24, #ESR_EL1_EC_IABT_EL0 // instruction abort in EL0 |
60ffc30d | 361 | b.eq el0_ia |
5c1ce6f7 | 362 | cmp x24, #ESR_EL1_EC_FP_ASIMD // FP/ASIMD access |
60ffc30d | 363 | b.eq el0_fpsimd_acc |
5c1ce6f7 | 364 | cmp x24, #ESR_EL1_EC_FP_EXC64 // FP/ASIMD exception |
60ffc30d | 365 | b.eq el0_fpsimd_exc |
5c1ce6f7 | 366 | cmp x24, #ESR_EL1_EC_SYS64 // configurable trap |
60ffc30d | 367 | b.eq el0_undef |
5c1ce6f7 | 368 | cmp x24, #ESR_EL1_EC_SP_ALIGN // stack alignment exception |
60ffc30d | 369 | b.eq el0_sp_pc |
5c1ce6f7 | 370 | cmp x24, #ESR_EL1_EC_PC_ALIGN // pc alignment exception |
60ffc30d | 371 | b.eq el0_sp_pc |
5c1ce6f7 | 372 | cmp x24, #ESR_EL1_EC_UNKNOWN // unknown exception in EL0 |
60ffc30d | 373 | b.eq el0_undef |
5c1ce6f7 | 374 | cmp x24, #ESR_EL1_EC_BREAKPT_EL0 // debug exception in EL0 |
60ffc30d CM |
375 | b.ge el0_dbg |
376 | b el0_inv | |
377 | ||
378 | #ifdef CONFIG_COMPAT | |
379 | .align 6 | |
380 | el0_sync_compat: | |
381 | kernel_entry 0, 32 | |
382 | mrs x25, esr_el1 // read the syndrome register | |
5c1ce6f7 MZ |
383 | lsr x24, x25, #ESR_EL1_EC_SHIFT // exception class |
384 | cmp x24, #ESR_EL1_EC_SVC32 // SVC in 32-bit state | |
60ffc30d | 385 | b.eq el0_svc_compat |
2a283070 | 386 | adr lr, ret_to_user |
5c1ce6f7 | 387 | cmp x24, #ESR_EL1_EC_DABT_EL0 // data abort in EL0 |
60ffc30d | 388 | b.eq el0_da |
5c1ce6f7 | 389 | cmp x24, #ESR_EL1_EC_IABT_EL0 // instruction abort in EL0 |
60ffc30d | 390 | b.eq el0_ia |
5c1ce6f7 | 391 | cmp x24, #ESR_EL1_EC_FP_ASIMD // FP/ASIMD access |
60ffc30d | 392 | b.eq el0_fpsimd_acc |
5c1ce6f7 | 393 | cmp x24, #ESR_EL1_EC_FP_EXC32 // FP/ASIMD exception |
60ffc30d | 394 | b.eq el0_fpsimd_exc |
5c1ce6f7 | 395 | cmp x24, #ESR_EL1_EC_UNKNOWN // unknown exception in EL0 |
60ffc30d | 396 | b.eq el0_undef |
381cc2b9 MR |
397 | cmp x24, #ESR_EL1_EC_CP15_32 // CP15 MRC/MCR trap |
398 | b.eq el0_undef | |
399 | cmp x24, #ESR_EL1_EC_CP15_64 // CP15 MRRC/MCRR trap | |
400 | b.eq el0_undef | |
401 | cmp x24, #ESR_EL1_EC_CP14_MR // CP14 MRC/MCR trap | |
402 | b.eq el0_undef | |
403 | cmp x24, #ESR_EL1_EC_CP14_LS // CP14 LDC/STC trap | |
404 | b.eq el0_undef | |
405 | cmp x24, #ESR_EL1_EC_CP14_64 // CP14 MRRC/MCRR trap | |
406 | b.eq el0_undef | |
5c1ce6f7 | 407 | cmp x24, #ESR_EL1_EC_BREAKPT_EL0 // debug exception in EL0 |
60ffc30d CM |
408 | b.ge el0_dbg |
409 | b el0_inv | |
410 | el0_svc_compat: | |
411 | /* | |
412 | * AArch32 syscall handling | |
413 | */ | |
414 | adr stbl, compat_sys_call_table // load compat syscall table pointer | |
415 | uxtw scno, w7 // syscall number in w7 (r7) | |
416 | mov sc_nr, #__NR_compat_syscalls | |
417 | b el0_svc_naked | |
418 | ||
419 | .align 6 | |
420 | el0_irq_compat: | |
421 | kernel_entry 0, 32 | |
422 | b el0_irq_naked | |
423 | #endif | |
424 | ||
425 | el0_da: | |
426 | /* | |
427 | * Data abort handling | |
428 | */ | |
429 | mrs x0, far_el1 | |
d50240a5 | 430 | bic x0, x0, #(0xff << 56) |
60ffc30d | 431 | // enable interrupts before calling the main handler |
2a283070 | 432 | enable_dbg_and_irq |
60ffc30d CM |
433 | mov x1, x25 |
434 | mov x2, sp | |
435 | b do_mem_abort | |
436 | el0_ia: | |
437 | /* | |
438 | * Instruction abort handling | |
439 | */ | |
440 | mrs x0, far_el1 | |
60ffc30d | 441 | // enable interrupts before calling the main handler |
2a283070 | 442 | enable_dbg_and_irq |
60ffc30d CM |
443 | orr x1, x25, #1 << 24 // use reserved ISS bit for instruction aborts |
444 | mov x2, sp | |
445 | b do_mem_abort | |
446 | el0_fpsimd_acc: | |
447 | /* | |
448 | * Floating Point or Advanced SIMD access | |
449 | */ | |
2a283070 | 450 | enable_dbg |
60ffc30d CM |
451 | mov x0, x25 |
452 | mov x1, sp | |
453 | b do_fpsimd_acc | |
454 | el0_fpsimd_exc: | |
455 | /* | |
456 | * Floating Point or Advanced SIMD exception | |
457 | */ | |
2a283070 | 458 | enable_dbg |
60ffc30d CM |
459 | mov x0, x25 |
460 | mov x1, sp | |
461 | b do_fpsimd_exc | |
462 | el0_sp_pc: | |
463 | /* | |
464 | * Stack or PC alignment exception handling | |
465 | */ | |
466 | mrs x0, far_el1 | |
60ffc30d | 467 | // enable interrupts before calling the main handler |
2a283070 | 468 | enable_dbg_and_irq |
60ffc30d CM |
469 | mov x1, x25 |
470 | mov x2, sp | |
471 | b do_sp_pc_abort | |
472 | el0_undef: | |
473 | /* | |
474 | * Undefined instruction | |
475 | */ | |
2600e130 | 476 | // enable interrupts before calling the main handler |
2a283070 WD |
477 | enable_dbg_and_irq |
478 | mov x0, sp | |
60ffc30d CM |
479 | b do_undefinstr |
480 | el0_dbg: | |
481 | /* | |
482 | * Debug exception handling | |
483 | */ | |
484 | tbnz x24, #0, el0_inv // EL0 only | |
485 | mrs x0, far_el1 | |
60ffc30d CM |
486 | mov x1, x25 |
487 | mov x2, sp | |
2a283070 WD |
488 | bl do_debug_exception |
489 | enable_dbg | |
490 | b ret_to_user | |
60ffc30d | 491 | el0_inv: |
2a283070 | 492 | enable_dbg |
60ffc30d CM |
493 | mov x0, sp |
494 | mov x1, #BAD_SYNC | |
495 | mrs x2, esr_el1 | |
496 | b bad_mode | |
497 | ENDPROC(el0_sync) | |
498 | ||
499 | .align 6 | |
500 | el0_irq: | |
501 | kernel_entry 0 | |
502 | el0_irq_naked: | |
60ffc30d CM |
503 | enable_dbg |
504 | #ifdef CONFIG_TRACE_IRQFLAGS | |
505 | bl trace_hardirqs_off | |
506 | #endif | |
64681787 | 507 | |
60ffc30d | 508 | irq_handler |
64681787 | 509 | |
60ffc30d CM |
510 | #ifdef CONFIG_TRACE_IRQFLAGS |
511 | bl trace_hardirqs_on | |
512 | #endif | |
513 | b ret_to_user | |
514 | ENDPROC(el0_irq) | |
515 | ||
60ffc30d CM |
516 | /* |
517 | * Register switch for AArch64. The callee-saved registers need to be saved | |
518 | * and restored. On entry: | |
519 | * x0 = previous task_struct (must be preserved across the switch) | |
520 | * x1 = next task_struct | |
521 | * Previous and next are guaranteed not to be the same. | |
522 | * | |
523 | */ | |
524 | ENTRY(cpu_switch_to) | |
525 | add x8, x0, #THREAD_CPU_CONTEXT | |
526 | mov x9, sp | |
527 | stp x19, x20, [x8], #16 // store callee-saved registers | |
528 | stp x21, x22, [x8], #16 | |
529 | stp x23, x24, [x8], #16 | |
530 | stp x25, x26, [x8], #16 | |
531 | stp x27, x28, [x8], #16 | |
532 | stp x29, x9, [x8], #16 | |
533 | str lr, [x8] | |
534 | add x8, x1, #THREAD_CPU_CONTEXT | |
535 | ldp x19, x20, [x8], #16 // restore callee-saved registers | |
536 | ldp x21, x22, [x8], #16 | |
537 | ldp x23, x24, [x8], #16 | |
538 | ldp x25, x26, [x8], #16 | |
539 | ldp x27, x28, [x8], #16 | |
540 | ldp x29, x9, [x8], #16 | |
541 | ldr lr, [x8] | |
542 | mov sp, x9 | |
543 | ret | |
544 | ENDPROC(cpu_switch_to) | |
545 | ||
546 | /* | |
547 | * This is the fast syscall return path. We do as little as possible here, | |
548 | * and this includes saving x0 back into the kernel stack. | |
549 | */ | |
550 | ret_fast_syscall: | |
551 | disable_irq // disable interrupts | |
552 | ldr x1, [tsk, #TI_FLAGS] | |
553 | and x2, x1, #_TIF_WORK_MASK | |
554 | cbnz x2, fast_work_pending | |
2a283070 | 555 | enable_step_tsk x1, x2 |
60ffc30d CM |
556 | kernel_exit 0, ret = 1 |
557 | ||
558 | /* | |
559 | * Ok, we need to do extra processing, enter the slow path. | |
560 | */ | |
561 | fast_work_pending: | |
562 | str x0, [sp, #S_X0] // returned x0 | |
563 | work_pending: | |
564 | tbnz x1, #TIF_NEED_RESCHED, work_resched | |
565 | /* TIF_SIGPENDING or TIF_NOTIFY_RESUME case */ | |
566 | ldr x2, [sp, #S_PSTATE] | |
567 | mov x0, sp // 'regs' | |
568 | tst x2, #PSR_MODE_MASK // user mode regs? | |
569 | b.ne no_work_pending // returning to kernel | |
6916fd08 | 570 | enable_irq // enable interrupts for do_notify_resume() |
60ffc30d CM |
571 | bl do_notify_resume |
572 | b ret_to_user | |
573 | work_resched: | |
60ffc30d CM |
574 | bl schedule |
575 | ||
576 | /* | |
577 | * "slow" syscall return path. | |
578 | */ | |
59dc67b0 | 579 | ret_to_user: |
60ffc30d CM |
580 | disable_irq // disable interrupts |
581 | ldr x1, [tsk, #TI_FLAGS] | |
582 | and x2, x1, #_TIF_WORK_MASK | |
583 | cbnz x2, work_pending | |
2a283070 | 584 | enable_step_tsk x1, x2 |
60ffc30d CM |
585 | no_work_pending: |
586 | kernel_exit 0, ret = 0 | |
587 | ENDPROC(ret_to_user) | |
588 | ||
589 | /* | |
590 | * This is how we return from a fork. | |
591 | */ | |
592 | ENTRY(ret_from_fork) | |
593 | bl schedule_tail | |
c34501d2 CM |
594 | cbz x19, 1f // not a kernel thread |
595 | mov x0, x20 | |
596 | blr x19 | |
597 | 1: get_thread_info tsk | |
60ffc30d CM |
598 | b ret_to_user |
599 | ENDPROC(ret_from_fork) | |
600 | ||
601 | /* | |
602 | * SVC handler. | |
603 | */ | |
604 | .align 6 | |
605 | el0_svc: | |
606 | adrp stbl, sys_call_table // load syscall table pointer | |
607 | uxtw scno, w8 // syscall number in w8 | |
608 | mov sc_nr, #__NR_syscalls | |
609 | el0_svc_naked: // compat entry point | |
610 | stp x0, scno, [sp, #S_ORIG_X0] // save the original x0 and syscall number | |
2a283070 | 611 | enable_dbg_and_irq |
60ffc30d | 612 | |
449f81a4 AT |
613 | ldr x16, [tsk, #TI_FLAGS] // check for syscall hooks |
614 | tst x16, #_TIF_SYSCALL_WORK | |
615 | b.ne __sys_trace | |
60ffc30d CM |
616 | adr lr, ret_fast_syscall // return address |
617 | cmp scno, sc_nr // check upper syscall limit | |
618 | b.hs ni_sys | |
619 | ldr x16, [stbl, scno, lsl #3] // address in the syscall table | |
620 | br x16 // call sys_* routine | |
621 | ni_sys: | |
622 | mov x0, sp | |
623 | b do_ni_syscall | |
624 | ENDPROC(el0_svc) | |
625 | ||
626 | /* | |
627 | * This is the really slow path. We're going to be doing context | |
628 | * switches, and waiting for our parent to respond. | |
629 | */ | |
630 | __sys_trace: | |
631 | mov x1, sp | |
632 | mov w0, #0 // trace entry | |
633 | bl syscall_trace | |
634 | adr lr, __sys_trace_return // return address | |
635 | uxtw scno, w0 // syscall number (possibly new) | |
636 | mov x1, sp // pointer to regs | |
637 | cmp scno, sc_nr // check upper syscall limit | |
638 | b.hs ni_sys | |
639 | ldp x0, x1, [sp] // restore the syscall args | |
640 | ldp x2, x3, [sp, #S_X2] | |
641 | ldp x4, x5, [sp, #S_X4] | |
642 | ldp x6, x7, [sp, #S_X6] | |
643 | ldr x16, [stbl, scno, lsl #3] // address in the syscall table | |
644 | br x16 // call sys_* routine | |
645 | ||
646 | __sys_trace_return: | |
647 | str x0, [sp] // save returned x0 | |
648 | mov x1, sp | |
649 | mov w0, #1 // trace exit | |
650 | bl syscall_trace | |
651 | b ret_to_user | |
652 | ||
653 | /* | |
654 | * Special system call wrappers. | |
655 | */ | |
60ffc30d CM |
656 | ENTRY(sys_rt_sigreturn_wrapper) |
657 | mov x0, sp | |
658 | b sys_rt_sigreturn | |
659 | ENDPROC(sys_rt_sigreturn_wrapper) | |
660 | ||
60ffc30d CM |
661 | ENTRY(handle_arch_irq) |
662 | .quad 0 |