Loading...
1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others.
7 * Copyright (C) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org)
8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
9 * Copyright (C) 2004 Thiemo Seufer
10 */
11#include <linux/errno.h>
12#include <linux/module.h>
13#include <linux/sched.h>
14#include <linux/tick.h>
15#include <linux/kernel.h>
16#include <linux/mm.h>
17#include <linux/stddef.h>
18#include <linux/unistd.h>
19#include <linux/ptrace.h>
20#include <linux/mman.h>
21#include <linux/personality.h>
22#include <linux/sys.h>
23#include <linux/user.h>
24#include <linux/init.h>
25#include <linux/completion.h>
26#include <linux/kallsyms.h>
27#include <linux/random.h>
28
29#include <asm/asm.h>
30#include <asm/bootinfo.h>
31#include <asm/cpu.h>
32#include <asm/dsp.h>
33#include <asm/fpu.h>
34#include <asm/pgtable.h>
35#include <asm/system.h>
36#include <asm/mipsregs.h>
37#include <asm/processor.h>
38#include <asm/uaccess.h>
39#include <asm/io.h>
40#include <asm/elf.h>
41#include <asm/isadep.h>
42#include <asm/inst.h>
43#include <asm/stacktrace.h>
44
45/*
46 * The idle thread. There's no useful work to be done, so just try to conserve
47 * power and have a low exit latency (ie sit in a loop waiting for somebody to
48 * say that they'd like to reschedule)
49 */
50void __noreturn cpu_idle(void)
51{
52 int cpu;
53
54 /* CPU is going idle. */
55 cpu = smp_processor_id();
56
57 /* endless idle loop with no priority at all */
58 while (1) {
59 tick_nohz_stop_sched_tick(1);
60 while (!need_resched() && cpu_online(cpu)) {
61#ifdef CONFIG_MIPS_MT_SMTC
62 extern void smtc_idle_loop_hook(void);
63
64 smtc_idle_loop_hook();
65#endif
66
67 if (cpu_wait) {
68 /* Don't trace irqs off for idle */
69 stop_critical_timings();
70 (*cpu_wait)();
71 start_critical_timings();
72 }
73 }
74#ifdef CONFIG_HOTPLUG_CPU
75 if (!cpu_online(cpu) && !cpu_isset(cpu, cpu_callin_map) &&
76 (system_state == SYSTEM_RUNNING ||
77 system_state == SYSTEM_BOOTING))
78 play_dead();
79#endif
80 tick_nohz_restart_sched_tick();
81 preempt_enable_no_resched();
82 schedule();
83 preempt_disable();
84 }
85}
86
87asmlinkage void ret_from_fork(void);
88
89void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
90{
91 unsigned long status;
92
93 /* New thread loses kernel privileges. */
94 status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK);
95#ifdef CONFIG_64BIT
96 status |= test_thread_flag(TIF_32BIT_REGS) ? 0 : ST0_FR;
97#endif
98 status |= KU_USER;
99 regs->cp0_status = status;
100 clear_used_math();
101 clear_fpu_owner();
102 if (cpu_has_dsp)
103 __init_dsp();
104 regs->cp0_epc = pc;
105 regs->regs[29] = sp;
106}
107
108void exit_thread(void)
109{
110}
111
112void flush_thread(void)
113{
114}
115
116int copy_thread(unsigned long clone_flags, unsigned long usp,
117 unsigned long unused, struct task_struct *p, struct pt_regs *regs)
118{
119 struct thread_info *ti = task_thread_info(p);
120 struct pt_regs *childregs;
121 unsigned long childksp;
122 p->set_child_tid = p->clear_child_tid = NULL;
123
124 childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
125
126 preempt_disable();
127
128 if (is_fpu_owner())
129 save_fp(p);
130
131 if (cpu_has_dsp)
132 save_dsp(p);
133
134 preempt_enable();
135
136 /* set up new TSS. */
137 childregs = (struct pt_regs *) childksp - 1;
138 /* Put the stack after the struct pt_regs. */
139 childksp = (unsigned long) childregs;
140 *childregs = *regs;
141 childregs->regs[7] = 0; /* Clear error flag */
142
143 childregs->regs[2] = 0; /* Child gets zero as return value */
144
145 if (childregs->cp0_status & ST0_CU0) {
146 childregs->regs[28] = (unsigned long) ti;
147 childregs->regs[29] = childksp;
148 ti->addr_limit = KERNEL_DS;
149 } else {
150 childregs->regs[29] = usp;
151 ti->addr_limit = USER_DS;
152 }
153 p->thread.reg29 = (unsigned long) childregs;
154 p->thread.reg31 = (unsigned long) ret_from_fork;
155
156 /*
157 * New tasks lose permission to use the fpu. This accelerates context
158 * switching for most programs since they don't use the fpu.
159 */
160 p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
161 childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
162
163#ifdef CONFIG_MIPS_MT_SMTC
164 /*
165 * SMTC restores TCStatus after Status, and the CU bits
166 * are aliased there.
167 */
168 childregs->cp0_tcstatus &= ~(ST0_CU2|ST0_CU1);
169#endif
170 clear_tsk_thread_flag(p, TIF_USEDFPU);
171
172#ifdef CONFIG_MIPS_MT_FPAFF
173 clear_tsk_thread_flag(p, TIF_FPUBOUND);
174#endif /* CONFIG_MIPS_MT_FPAFF */
175
176 if (clone_flags & CLONE_SETTLS)
177 ti->tp_value = regs->regs[7];
178
179 return 0;
180}
181
182/* Fill in the fpu structure for a core dump.. */
183int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
184{
185 memcpy(r, ¤t->thread.fpu, sizeof(current->thread.fpu));
186
187 return 1;
188}
189
190void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs)
191{
192 int i;
193
194 for (i = 0; i < EF_R0; i++)
195 gp[i] = 0;
196 gp[EF_R0] = 0;
197 for (i = 1; i <= 31; i++)
198 gp[EF_R0 + i] = regs->regs[i];
199 gp[EF_R26] = 0;
200 gp[EF_R27] = 0;
201 gp[EF_LO] = regs->lo;
202 gp[EF_HI] = regs->hi;
203 gp[EF_CP0_EPC] = regs->cp0_epc;
204 gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
205 gp[EF_CP0_STATUS] = regs->cp0_status;
206 gp[EF_CP0_CAUSE] = regs->cp0_cause;
207#ifdef EF_UNUSED0
208 gp[EF_UNUSED0] = 0;
209#endif
210}
211
212int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
213{
214 elf_dump_regs(*regs, task_pt_regs(tsk));
215 return 1;
216}
217
218int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr)
219{
220 memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
221
222 return 1;
223}
224
225/*
226 * Create a kernel thread
227 */
228static void __noreturn kernel_thread_helper(void *arg, int (*fn)(void *))
229{
230 do_exit(fn(arg));
231}
232
233long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
234{
235 struct pt_regs regs;
236
237 memset(®s, 0, sizeof(regs));
238
239 regs.regs[4] = (unsigned long) arg;
240 regs.regs[5] = (unsigned long) fn;
241 regs.cp0_epc = (unsigned long) kernel_thread_helper;
242 regs.cp0_status = read_c0_status();
243#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
244 regs.cp0_status = (regs.cp0_status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
245 ((regs.cp0_status & (ST0_KUC | ST0_IEC)) << 2);
246#else
247 regs.cp0_status |= ST0_EXL;
248#endif
249
250 /* Ok, create the new process.. */
251 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
252}
253
254/*
255 *
256 */
257struct mips_frame_info {
258 void *func;
259 unsigned long func_size;
260 int frame_size;
261 int pc_offset;
262};
263
264static inline int is_ra_save_ins(union mips_instruction *ip)
265{
266 /* sw / sd $ra, offset($sp) */
267 return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) &&
268 ip->i_format.rs == 29 &&
269 ip->i_format.rt == 31;
270}
271
272static inline int is_jal_jalr_jr_ins(union mips_instruction *ip)
273{
274 if (ip->j_format.opcode == jal_op)
275 return 1;
276 if (ip->r_format.opcode != spec_op)
277 return 0;
278 return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;
279}
280
281static inline int is_sp_move_ins(union mips_instruction *ip)
282{
283 /* addiu/daddiu sp,sp,-imm */
284 if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
285 return 0;
286 if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
287 return 1;
288 return 0;
289}
290
291static int get_frame_info(struct mips_frame_info *info)
292{
293 union mips_instruction *ip = info->func;
294 unsigned max_insns = info->func_size / sizeof(union mips_instruction);
295 unsigned i;
296
297 info->pc_offset = -1;
298 info->frame_size = 0;
299
300 if (!ip)
301 goto err;
302
303 if (max_insns == 0)
304 max_insns = 128U; /* unknown function size */
305 max_insns = min(128U, max_insns);
306
307 for (i = 0; i < max_insns; i++, ip++) {
308
309 if (is_jal_jalr_jr_ins(ip))
310 break;
311 if (!info->frame_size) {
312 if (is_sp_move_ins(ip))
313 info->frame_size = - ip->i_format.simmediate;
314 continue;
315 }
316 if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
317 info->pc_offset =
318 ip->i_format.simmediate / sizeof(long);
319 break;
320 }
321 }
322 if (info->frame_size && info->pc_offset >= 0) /* nested */
323 return 0;
324 if (info->pc_offset < 0) /* leaf */
325 return 1;
326 /* prologue seems boggus... */
327err:
328 return -1;
329}
330
331static struct mips_frame_info schedule_mfi __read_mostly;
332
333static int __init frame_info_init(void)
334{
335 unsigned long size = 0;
336#ifdef CONFIG_KALLSYMS
337 unsigned long ofs;
338
339 kallsyms_lookup_size_offset((unsigned long)schedule, &size, &ofs);
340#endif
341 schedule_mfi.func = schedule;
342 schedule_mfi.func_size = size;
343
344 get_frame_info(&schedule_mfi);
345
346 /*
347 * Without schedule() frame info, result given by
348 * thread_saved_pc() and get_wchan() are not reliable.
349 */
350 if (schedule_mfi.pc_offset < 0)
351 printk("Can't analyze schedule() prologue at %p\n", schedule);
352
353 return 0;
354}
355
356arch_initcall(frame_info_init);
357
358/*
359 * Return saved PC of a blocked thread.
360 */
361unsigned long thread_saved_pc(struct task_struct *tsk)
362{
363 struct thread_struct *t = &tsk->thread;
364
365 /* New born processes are a special case */
366 if (t->reg31 == (unsigned long) ret_from_fork)
367 return t->reg31;
368 if (schedule_mfi.pc_offset < 0)
369 return 0;
370 return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
371}
372
373
374#ifdef CONFIG_KALLSYMS
375/* generic stack unwinding function */
376unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
377 unsigned long *sp,
378 unsigned long pc,
379 unsigned long *ra)
380{
381 struct mips_frame_info info;
382 unsigned long size, ofs;
383 int leaf;
384 extern void ret_from_irq(void);
385 extern void ret_from_exception(void);
386
387 if (!stack_page)
388 return 0;
389
390 /*
391 * If we reached the bottom of interrupt context,
392 * return saved pc in pt_regs.
393 */
394 if (pc == (unsigned long)ret_from_irq ||
395 pc == (unsigned long)ret_from_exception) {
396 struct pt_regs *regs;
397 if (*sp >= stack_page &&
398 *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {
399 regs = (struct pt_regs *)*sp;
400 pc = regs->cp0_epc;
401 if (__kernel_text_address(pc)) {
402 *sp = regs->regs[29];
403 *ra = regs->regs[31];
404 return pc;
405 }
406 }
407 return 0;
408 }
409 if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
410 return 0;
411 /*
412 * Return ra if an exception occurred at the first instruction
413 */
414 if (unlikely(ofs == 0)) {
415 pc = *ra;
416 *ra = 0;
417 return pc;
418 }
419
420 info.func = (void *)(pc - ofs);
421 info.func_size = ofs; /* analyze from start to ofs */
422 leaf = get_frame_info(&info);
423 if (leaf < 0)
424 return 0;
425
426 if (*sp < stack_page ||
427 *sp + info.frame_size > stack_page + THREAD_SIZE - 32)
428 return 0;
429
430 if (leaf)
431 /*
432 * For some extreme cases, get_frame_info() can
433 * consider wrongly a nested function as a leaf
434 * one. In that cases avoid to return always the
435 * same value.
436 */
437 pc = pc != *ra ? *ra : 0;
438 else
439 pc = ((unsigned long *)(*sp))[info.pc_offset];
440
441 *sp += info.frame_size;
442 *ra = 0;
443 return __kernel_text_address(pc) ? pc : 0;
444}
445EXPORT_SYMBOL(unwind_stack_by_address);
446
447/* used by show_backtrace() */
448unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
449 unsigned long pc, unsigned long *ra)
450{
451 unsigned long stack_page = (unsigned long)task_stack_page(task);
452 return unwind_stack_by_address(stack_page, sp, pc, ra);
453}
454#endif
455
456/*
457 * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
458 */
459unsigned long get_wchan(struct task_struct *task)
460{
461 unsigned long pc = 0;
462#ifdef CONFIG_KALLSYMS
463 unsigned long sp;
464 unsigned long ra = 0;
465#endif
466
467 if (!task || task == current || task->state == TASK_RUNNING)
468 goto out;
469 if (!task_stack_page(task))
470 goto out;
471
472 pc = thread_saved_pc(task);
473
474#ifdef CONFIG_KALLSYMS
475 sp = task->thread.reg29 + schedule_mfi.frame_size;
476
477 while (in_sched_functions(pc))
478 pc = unwind_stack(task, &sp, pc, &ra);
479#endif
480
481out:
482 return pc;
483}
484
485/*
486 * Don't forget that the stack pointer must be aligned on a 8 bytes
487 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
488 */
489unsigned long arch_align_stack(unsigned long sp)
490{
491 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
492 sp -= get_random_int() & ~PAGE_MASK;
493
494 return sp & ALMASK;
495}
1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others.
7 * Copyright (C) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org)
8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
9 * Copyright (C) 2004 Thiemo Seufer
10 * Copyright (C) 2013 Imagination Technologies Ltd.
11 */
12#include <linux/errno.h>
13#include <linux/sched.h>
14#include <linux/tick.h>
15#include <linux/kernel.h>
16#include <linux/mm.h>
17#include <linux/stddef.h>
18#include <linux/unistd.h>
19#include <linux/export.h>
20#include <linux/ptrace.h>
21#include <linux/mman.h>
22#include <linux/personality.h>
23#include <linux/sys.h>
24#include <linux/init.h>
25#include <linux/completion.h>
26#include <linux/kallsyms.h>
27#include <linux/random.h>
28#include <linux/prctl.h>
29
30#include <asm/asm.h>
31#include <asm/bootinfo.h>
32#include <asm/cpu.h>
33#include <asm/dsemul.h>
34#include <asm/dsp.h>
35#include <asm/fpu.h>
36#include <asm/irq.h>
37#include <asm/msa.h>
38#include <asm/pgtable.h>
39#include <asm/mipsregs.h>
40#include <asm/processor.h>
41#include <asm/reg.h>
42#include <linux/uaccess.h>
43#include <asm/io.h>
44#include <asm/elf.h>
45#include <asm/isadep.h>
46#include <asm/inst.h>
47#include <asm/stacktrace.h>
48#include <asm/irq_regs.h>
49
50#ifdef CONFIG_HOTPLUG_CPU
51void arch_cpu_idle_dead(void)
52{
53 /* What the heck is this check doing ? */
54 if (!cpumask_test_cpu(smp_processor_id(), &cpu_callin_map))
55 play_dead();
56}
57#endif
58
59asmlinkage void ret_from_fork(void);
60asmlinkage void ret_from_kernel_thread(void);
61
62void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
63{
64 unsigned long status;
65
66 /* New thread loses kernel privileges. */
67 status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK);
68 status |= KU_USER;
69 regs->cp0_status = status;
70 lose_fpu(0);
71 clear_thread_flag(TIF_MSA_CTX_LIVE);
72 clear_used_math();
73 atomic_set(¤t->thread.bd_emu_frame, BD_EMUFRAME_NONE);
74 init_dsp();
75 regs->cp0_epc = pc;
76 regs->regs[29] = sp;
77}
78
79void exit_thread(struct task_struct *tsk)
80{
81 /*
82 * User threads may have allocated a delay slot emulation frame.
83 * If so, clean up that allocation.
84 */
85 if (!(current->flags & PF_KTHREAD))
86 dsemul_thread_cleanup(tsk);
87}
88
89int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
90{
91 /*
92 * Save any process state which is live in hardware registers to the
93 * parent context prior to duplication. This prevents the new child
94 * state becoming stale if the parent is preempted before copy_thread()
95 * gets a chance to save the parent's live hardware registers to the
96 * child context.
97 */
98 preempt_disable();
99
100 if (is_msa_enabled())
101 save_msa(current);
102 else if (is_fpu_owner())
103 _save_fp(current);
104
105 save_dsp(current);
106
107 preempt_enable();
108
109 *dst = *src;
110 return 0;
111}
112
113/*
114 * Copy architecture-specific thread state
115 */
116int copy_thread(unsigned long clone_flags, unsigned long usp,
117 unsigned long kthread_arg, struct task_struct *p)
118{
119 struct thread_info *ti = task_thread_info(p);
120 struct pt_regs *childregs, *regs = current_pt_regs();
121 unsigned long childksp;
122 p->set_child_tid = p->clear_child_tid = NULL;
123
124 childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
125
126 /* set up new TSS. */
127 childregs = (struct pt_regs *) childksp - 1;
128 /* Put the stack after the struct pt_regs. */
129 childksp = (unsigned long) childregs;
130 p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
131 if (unlikely(p->flags & PF_KTHREAD)) {
132 /* kernel thread */
133 unsigned long status = p->thread.cp0_status;
134 memset(childregs, 0, sizeof(struct pt_regs));
135 ti->addr_limit = KERNEL_DS;
136 p->thread.reg16 = usp; /* fn */
137 p->thread.reg17 = kthread_arg;
138 p->thread.reg29 = childksp;
139 p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
140#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
141 status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
142 ((status & (ST0_KUC | ST0_IEC)) << 2);
143#else
144 status |= ST0_EXL;
145#endif
146 childregs->cp0_status = status;
147 return 0;
148 }
149
150 /* user thread */
151 *childregs = *regs;
152 childregs->regs[7] = 0; /* Clear error flag */
153 childregs->regs[2] = 0; /* Child gets zero as return value */
154 if (usp)
155 childregs->regs[29] = usp;
156 ti->addr_limit = USER_DS;
157
158 p->thread.reg29 = (unsigned long) childregs;
159 p->thread.reg31 = (unsigned long) ret_from_fork;
160
161 /*
162 * New tasks lose permission to use the fpu. This accelerates context
163 * switching for most programs since they don't use the fpu.
164 */
165 childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
166
167 clear_tsk_thread_flag(p, TIF_USEDFPU);
168 clear_tsk_thread_flag(p, TIF_USEDMSA);
169 clear_tsk_thread_flag(p, TIF_MSA_CTX_LIVE);
170
171#ifdef CONFIG_MIPS_MT_FPAFF
172 clear_tsk_thread_flag(p, TIF_FPUBOUND);
173#endif /* CONFIG_MIPS_MT_FPAFF */
174
175 atomic_set(&p->thread.bd_emu_frame, BD_EMUFRAME_NONE);
176
177 if (clone_flags & CLONE_SETTLS)
178 ti->tp_value = regs->regs[7];
179
180 return 0;
181}
182
183#ifdef CONFIG_CC_STACKPROTECTOR
184#include <linux/stackprotector.h>
185unsigned long __stack_chk_guard __read_mostly;
186EXPORT_SYMBOL(__stack_chk_guard);
187#endif
188
189struct mips_frame_info {
190 void *func;
191 unsigned long func_size;
192 int frame_size;
193 int pc_offset;
194};
195
196#define J_TARGET(pc,target) \
197 (((unsigned long)(pc) & 0xf0000000) | ((target) << 2))
198
199static inline int is_ra_save_ins(union mips_instruction *ip, int *poff)
200{
201#ifdef CONFIG_CPU_MICROMIPS
202 /*
203 * swsp ra,offset
204 * swm16 reglist,offset(sp)
205 * swm32 reglist,offset(sp)
206 * sw32 ra,offset(sp)
207 * jradiussp - NOT SUPPORTED
208 *
209 * microMIPS is way more fun...
210 */
211 if (mm_insn_16bit(ip->halfword[1])) {
212 switch (ip->mm16_r5_format.opcode) {
213 case mm_swsp16_op:
214 if (ip->mm16_r5_format.rt != 31)
215 return 0;
216
217 *poff = ip->mm16_r5_format.simmediate;
218 *poff = (*poff << 2) / sizeof(ulong);
219 return 1;
220
221 case mm_pool16c_op:
222 switch (ip->mm16_m_format.func) {
223 case mm_swm16_op:
224 *poff = ip->mm16_m_format.imm;
225 *poff += 1 + ip->mm16_m_format.rlist;
226 *poff = (*poff << 2) / sizeof(ulong);
227 return 1;
228
229 default:
230 return 0;
231 }
232
233 default:
234 return 0;
235 }
236 }
237
238 switch (ip->i_format.opcode) {
239 case mm_sw32_op:
240 if (ip->i_format.rs != 29)
241 return 0;
242 if (ip->i_format.rt != 31)
243 return 0;
244
245 *poff = ip->i_format.simmediate / sizeof(ulong);
246 return 1;
247
248 case mm_pool32b_op:
249 switch (ip->mm_m_format.func) {
250 case mm_swm32_func:
251 if (ip->mm_m_format.rd < 0x10)
252 return 0;
253 if (ip->mm_m_format.base != 29)
254 return 0;
255
256 *poff = ip->mm_m_format.simmediate;
257 *poff += (ip->mm_m_format.rd & 0xf) * sizeof(u32);
258 *poff /= sizeof(ulong);
259 return 1;
260 default:
261 return 0;
262 }
263
264 default:
265 return 0;
266 }
267#else
268 /* sw / sd $ra, offset($sp) */
269 if ((ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) &&
270 ip->i_format.rs == 29 && ip->i_format.rt == 31) {
271 *poff = ip->i_format.simmediate / sizeof(ulong);
272 return 1;
273 }
274
275 return 0;
276#endif
277}
278
279static inline int is_jump_ins(union mips_instruction *ip)
280{
281#ifdef CONFIG_CPU_MICROMIPS
282 /*
283 * jr16,jrc,jalr16,jalr16
284 * jal
285 * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb
286 * jraddiusp - NOT SUPPORTED
287 *
288 * microMIPS is kind of more fun...
289 */
290 if (mm_insn_16bit(ip->halfword[1])) {
291 if ((ip->mm16_r5_format.opcode == mm_pool16c_op &&
292 (ip->mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op))
293 return 1;
294 return 0;
295 }
296
297 if (ip->j_format.opcode == mm_j32_op)
298 return 1;
299 if (ip->j_format.opcode == mm_jal32_op)
300 return 1;
301 if (ip->r_format.opcode != mm_pool32a_op ||
302 ip->r_format.func != mm_pool32axf_op)
303 return 0;
304 return ((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op;
305#else
306 if (ip->j_format.opcode == j_op)
307 return 1;
308 if (ip->j_format.opcode == jal_op)
309 return 1;
310 if (ip->r_format.opcode != spec_op)
311 return 0;
312 return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;
313#endif
314}
315
316static inline int is_sp_move_ins(union mips_instruction *ip)
317{
318#ifdef CONFIG_CPU_MICROMIPS
319 /*
320 * addiusp -imm
321 * addius5 sp,-imm
322 * addiu32 sp,sp,-imm
323 * jradiussp - NOT SUPPORTED
324 *
325 * microMIPS is not more fun...
326 */
327 if (mm_insn_16bit(ip->halfword[1])) {
328 return (ip->mm16_r3_format.opcode == mm_pool16d_op &&
329 ip->mm16_r3_format.simmediate && mm_addiusp_func) ||
330 (ip->mm16_r5_format.opcode == mm_pool16d_op &&
331 ip->mm16_r5_format.rt == 29);
332 }
333
334 return ip->mm_i_format.opcode == mm_addiu32_op &&
335 ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29;
336#else
337 /* addiu/daddiu sp,sp,-imm */
338 if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
339 return 0;
340 if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
341 return 1;
342#endif
343 return 0;
344}
345
346static int get_frame_info(struct mips_frame_info *info)
347{
348 bool is_mmips = IS_ENABLED(CONFIG_CPU_MICROMIPS);
349 union mips_instruction insn, *ip, *ip_end;
350 const unsigned int max_insns = 128;
351 unsigned int i;
352
353 info->pc_offset = -1;
354 info->frame_size = 0;
355
356 ip = (void *)msk_isa16_mode((ulong)info->func);
357 if (!ip)
358 goto err;
359
360 ip_end = (void *)ip + info->func_size;
361
362 for (i = 0; i < max_insns && ip < ip_end; i++, ip++) {
363 if (is_mmips && mm_insn_16bit(ip->halfword[0])) {
364 insn.halfword[0] = 0;
365 insn.halfword[1] = ip->halfword[0];
366 } else if (is_mmips) {
367 insn.halfword[0] = ip->halfword[1];
368 insn.halfword[1] = ip->halfword[0];
369 } else {
370 insn.word = ip->word;
371 }
372
373 if (is_jump_ins(&insn))
374 break;
375
376 if (!info->frame_size) {
377 if (is_sp_move_ins(&insn))
378 {
379#ifdef CONFIG_CPU_MICROMIPS
380 if (mm_insn_16bit(ip->halfword[0]))
381 {
382 unsigned short tmp;
383
384 if (ip->halfword[0] & mm_addiusp_func)
385 {
386 tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2);
387 info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0));
388 } else {
389 tmp = (ip->halfword[0] >> 1);
390 info->frame_size = -(signed short)(tmp & 0xf);
391 }
392 ip = (void *) &ip->halfword[1];
393 ip--;
394 } else
395#endif
396 info->frame_size = - ip->i_format.simmediate;
397 }
398 continue;
399 }
400 if (info->pc_offset == -1 &&
401 is_ra_save_ins(&insn, &info->pc_offset))
402 break;
403 }
404 if (info->frame_size && info->pc_offset >= 0) /* nested */
405 return 0;
406 if (info->pc_offset < 0) /* leaf */
407 return 1;
408 /* prologue seems bogus... */
409err:
410 return -1;
411}
412
413static struct mips_frame_info schedule_mfi __read_mostly;
414
415#ifdef CONFIG_KALLSYMS
416static unsigned long get___schedule_addr(void)
417{
418 return kallsyms_lookup_name("__schedule");
419}
420#else
421static unsigned long get___schedule_addr(void)
422{
423 union mips_instruction *ip = (void *)schedule;
424 int max_insns = 8;
425 int i;
426
427 for (i = 0; i < max_insns; i++, ip++) {
428 if (ip->j_format.opcode == j_op)
429 return J_TARGET(ip, ip->j_format.target);
430 }
431 return 0;
432}
433#endif
434
435static int __init frame_info_init(void)
436{
437 unsigned long size = 0;
438#ifdef CONFIG_KALLSYMS
439 unsigned long ofs;
440#endif
441 unsigned long addr;
442
443 addr = get___schedule_addr();
444 if (!addr)
445 addr = (unsigned long)schedule;
446
447#ifdef CONFIG_KALLSYMS
448 kallsyms_lookup_size_offset(addr, &size, &ofs);
449#endif
450 schedule_mfi.func = (void *)addr;
451 schedule_mfi.func_size = size;
452
453 get_frame_info(&schedule_mfi);
454
455 /*
456 * Without schedule() frame info, result given by
457 * thread_saved_pc() and get_wchan() are not reliable.
458 */
459 if (schedule_mfi.pc_offset < 0)
460 printk("Can't analyze schedule() prologue at %p\n", schedule);
461
462 return 0;
463}
464
465arch_initcall(frame_info_init);
466
467/*
468 * Return saved PC of a blocked thread.
469 */
470unsigned long thread_saved_pc(struct task_struct *tsk)
471{
472 struct thread_struct *t = &tsk->thread;
473
474 /* New born processes are a special case */
475 if (t->reg31 == (unsigned long) ret_from_fork)
476 return t->reg31;
477 if (schedule_mfi.pc_offset < 0)
478 return 0;
479 return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
480}
481
482
483#ifdef CONFIG_KALLSYMS
484/* generic stack unwinding function */
485unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
486 unsigned long *sp,
487 unsigned long pc,
488 unsigned long *ra)
489{
490 struct mips_frame_info info;
491 unsigned long size, ofs;
492 int leaf;
493 extern void ret_from_irq(void);
494 extern void ret_from_exception(void);
495
496 if (!stack_page)
497 return 0;
498
499 /*
500 * If we reached the bottom of interrupt context,
501 * return saved pc in pt_regs.
502 */
503 if (pc == (unsigned long)ret_from_irq ||
504 pc == (unsigned long)ret_from_exception) {
505 struct pt_regs *regs;
506 if (*sp >= stack_page &&
507 *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {
508 regs = (struct pt_regs *)*sp;
509 pc = regs->cp0_epc;
510 if (!user_mode(regs) && __kernel_text_address(pc)) {
511 *sp = regs->regs[29];
512 *ra = regs->regs[31];
513 return pc;
514 }
515 }
516 return 0;
517 }
518 if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
519 return 0;
520 /*
521 * Return ra if an exception occurred at the first instruction
522 */
523 if (unlikely(ofs == 0)) {
524 pc = *ra;
525 *ra = 0;
526 return pc;
527 }
528
529 info.func = (void *)(pc - ofs);
530 info.func_size = ofs; /* analyze from start to ofs */
531 leaf = get_frame_info(&info);
532 if (leaf < 0)
533 return 0;
534
535 if (*sp < stack_page ||
536 *sp + info.frame_size > stack_page + THREAD_SIZE - 32)
537 return 0;
538
539 if (leaf)
540 /*
541 * For some extreme cases, get_frame_info() can
542 * consider wrongly a nested function as a leaf
543 * one. In that cases avoid to return always the
544 * same value.
545 */
546 pc = pc != *ra ? *ra : 0;
547 else
548 pc = ((unsigned long *)(*sp))[info.pc_offset];
549
550 *sp += info.frame_size;
551 *ra = 0;
552 return __kernel_text_address(pc) ? pc : 0;
553}
554EXPORT_SYMBOL(unwind_stack_by_address);
555
556/* used by show_backtrace() */
557unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
558 unsigned long pc, unsigned long *ra)
559{
560 unsigned long stack_page = 0;
561 int cpu;
562
563 for_each_possible_cpu(cpu) {
564 if (on_irq_stack(cpu, *sp)) {
565 stack_page = (unsigned long)irq_stack[cpu];
566 break;
567 }
568 }
569
570 if (!stack_page)
571 stack_page = (unsigned long)task_stack_page(task);
572
573 return unwind_stack_by_address(stack_page, sp, pc, ra);
574}
575#endif
576
577/*
578 * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
579 */
580unsigned long get_wchan(struct task_struct *task)
581{
582 unsigned long pc = 0;
583#ifdef CONFIG_KALLSYMS
584 unsigned long sp;
585 unsigned long ra = 0;
586#endif
587
588 if (!task || task == current || task->state == TASK_RUNNING)
589 goto out;
590 if (!task_stack_page(task))
591 goto out;
592
593 pc = thread_saved_pc(task);
594
595#ifdef CONFIG_KALLSYMS
596 sp = task->thread.reg29 + schedule_mfi.frame_size;
597
598 while (in_sched_functions(pc))
599 pc = unwind_stack(task, &sp, pc, &ra);
600#endif
601
602out:
603 return pc;
604}
605
606/*
607 * Don't forget that the stack pointer must be aligned on a 8 bytes
608 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
609 */
610unsigned long arch_align_stack(unsigned long sp)
611{
612 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
613 sp -= get_random_int() & ~PAGE_MASK;
614
615 return sp & ALMASK;
616}
617
618static void arch_dump_stack(void *info)
619{
620 struct pt_regs *regs;
621
622 regs = get_irq_regs();
623
624 if (regs)
625 show_regs(regs);
626
627 dump_stack();
628}
629
630void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
631{
632 long this_cpu = get_cpu();
633
634 if (cpumask_test_cpu(this_cpu, mask) && !exclude_self)
635 dump_stack();
636
637 smp_call_function_many(mask, arch_dump_stack, NULL, 1);
638
639 put_cpu();
640}
641
642int mips_get_process_fp_mode(struct task_struct *task)
643{
644 int value = 0;
645
646 if (!test_tsk_thread_flag(task, TIF_32BIT_FPREGS))
647 value |= PR_FP_MODE_FR;
648 if (test_tsk_thread_flag(task, TIF_HYBRID_FPREGS))
649 value |= PR_FP_MODE_FRE;
650
651 return value;
652}
653
654static void prepare_for_fp_mode_switch(void *info)
655{
656 struct mm_struct *mm = info;
657
658 if (current->mm == mm)
659 lose_fpu(1);
660}
661
662int mips_set_process_fp_mode(struct task_struct *task, unsigned int value)
663{
664 const unsigned int known_bits = PR_FP_MODE_FR | PR_FP_MODE_FRE;
665 struct task_struct *t;
666 int max_users;
667
668 /* Check the value is valid */
669 if (value & ~known_bits)
670 return -EOPNOTSUPP;
671
672 /* Avoid inadvertently triggering emulation */
673 if ((value & PR_FP_MODE_FR) && raw_cpu_has_fpu &&
674 !(raw_current_cpu_data.fpu_id & MIPS_FPIR_F64))
675 return -EOPNOTSUPP;
676 if ((value & PR_FP_MODE_FRE) && raw_cpu_has_fpu && !cpu_has_fre)
677 return -EOPNOTSUPP;
678
679 /* FR = 0 not supported in MIPS R6 */
680 if (!(value & PR_FP_MODE_FR) && raw_cpu_has_fpu && cpu_has_mips_r6)
681 return -EOPNOTSUPP;
682
683 /* Proceed with the mode switch */
684 preempt_disable();
685
686 /* Save FP & vector context, then disable FPU & MSA */
687 if (task->signal == current->signal)
688 lose_fpu(1);
689
690 /* Prevent any threads from obtaining live FP context */
691 atomic_set(&task->mm->context.fp_mode_switching, 1);
692 smp_mb__after_atomic();
693
694 /*
695 * If there are multiple online CPUs then force any which are running
696 * threads in this process to lose their FPU context, which they can't
697 * regain until fp_mode_switching is cleared later.
698 */
699 if (num_online_cpus() > 1) {
700 /* No need to send an IPI for the local CPU */
701 max_users = (task->mm == current->mm) ? 1 : 0;
702
703 if (atomic_read(¤t->mm->mm_users) > max_users)
704 smp_call_function(prepare_for_fp_mode_switch,
705 (void *)current->mm, 1);
706 }
707
708 /*
709 * There are now no threads of the process with live FP context, so it
710 * is safe to proceed with the FP mode switch.
711 */
712 for_each_thread(task, t) {
713 /* Update desired FP register width */
714 if (value & PR_FP_MODE_FR) {
715 clear_tsk_thread_flag(t, TIF_32BIT_FPREGS);
716 } else {
717 set_tsk_thread_flag(t, TIF_32BIT_FPREGS);
718 clear_tsk_thread_flag(t, TIF_MSA_CTX_LIVE);
719 }
720
721 /* Update desired FP single layout */
722 if (value & PR_FP_MODE_FRE)
723 set_tsk_thread_flag(t, TIF_HYBRID_FPREGS);
724 else
725 clear_tsk_thread_flag(t, TIF_HYBRID_FPREGS);
726 }
727
728 /* Allow threads to use FP again */
729 atomic_set(&task->mm->context.fp_mode_switching, 0);
730 preempt_enable();
731
732 return 0;
733}