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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/dsp.h>
34#include <asm/fpu.h>
35#include <asm/msa.h>
36#include <asm/pgtable.h>
37#include <asm/mipsregs.h>
38#include <asm/processor.h>
39#include <asm/reg.h>
40#include <asm/uaccess.h>
41#include <asm/io.h>
42#include <asm/elf.h>
43#include <asm/isadep.h>
44#include <asm/inst.h>
45#include <asm/stacktrace.h>
46#include <asm/irq_regs.h>
47
48#ifdef CONFIG_HOTPLUG_CPU
49void arch_cpu_idle_dead(void)
50{
51 /* What the heck is this check doing ? */
52 if (!cpumask_test_cpu(smp_processor_id(), &cpu_callin_map))
53 play_dead();
54}
55#endif
56
57asmlinkage void ret_from_fork(void);
58asmlinkage void ret_from_kernel_thread(void);
59
60void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
61{
62 unsigned long status;
63
64 /* New thread loses kernel privileges. */
65 status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK);
66 status |= KU_USER;
67 regs->cp0_status = status;
68 lose_fpu(0);
69 clear_thread_flag(TIF_MSA_CTX_LIVE);
70 clear_used_math();
71 init_dsp();
72 regs->cp0_epc = pc;
73 regs->regs[29] = sp;
74}
75
76void exit_thread(void)
77{
78}
79
80void flush_thread(void)
81{
82}
83
84int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
85{
86 /*
87 * Save any process state which is live in hardware registers to the
88 * parent context prior to duplication. This prevents the new child
89 * state becoming stale if the parent is preempted before copy_thread()
90 * gets a chance to save the parent's live hardware registers to the
91 * child context.
92 */
93 preempt_disable();
94
95 if (is_msa_enabled())
96 save_msa(current);
97 else if (is_fpu_owner())
98 _save_fp(current);
99
100 save_dsp(current);
101
102 preempt_enable();
103
104 *dst = *src;
105 return 0;
106}
107
108/*
109 * Copy architecture-specific thread state
110 */
111int copy_thread(unsigned long clone_flags, unsigned long usp,
112 unsigned long kthread_arg, struct task_struct *p)
113{
114 struct thread_info *ti = task_thread_info(p);
115 struct pt_regs *childregs, *regs = current_pt_regs();
116 unsigned long childksp;
117 p->set_child_tid = p->clear_child_tid = NULL;
118
119 childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
120
121 /* set up new TSS. */
122 childregs = (struct pt_regs *) childksp - 1;
123 /* Put the stack after the struct pt_regs. */
124 childksp = (unsigned long) childregs;
125 p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
126 if (unlikely(p->flags & PF_KTHREAD)) {
127 /* kernel thread */
128 unsigned long status = p->thread.cp0_status;
129 memset(childregs, 0, sizeof(struct pt_regs));
130 ti->addr_limit = KERNEL_DS;
131 p->thread.reg16 = usp; /* fn */
132 p->thread.reg17 = kthread_arg;
133 p->thread.reg29 = childksp;
134 p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
135#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
136 status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
137 ((status & (ST0_KUC | ST0_IEC)) << 2);
138#else
139 status |= ST0_EXL;
140#endif
141 childregs->cp0_status = status;
142 return 0;
143 }
144
145 /* user thread */
146 *childregs = *regs;
147 childregs->regs[7] = 0; /* Clear error flag */
148 childregs->regs[2] = 0; /* Child gets zero as return value */
149 if (usp)
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 childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
161
162 clear_tsk_thread_flag(p, TIF_USEDFPU);
163 clear_tsk_thread_flag(p, TIF_USEDMSA);
164 clear_tsk_thread_flag(p, TIF_MSA_CTX_LIVE);
165
166#ifdef CONFIG_MIPS_MT_FPAFF
167 clear_tsk_thread_flag(p, TIF_FPUBOUND);
168#endif /* CONFIG_MIPS_MT_FPAFF */
169
170 if (clone_flags & CLONE_SETTLS)
171 ti->tp_value = regs->regs[7];
172
173 return 0;
174}
175
176#ifdef CONFIG_CC_STACKPROTECTOR
177#include <linux/stackprotector.h>
178unsigned long __stack_chk_guard __read_mostly;
179EXPORT_SYMBOL(__stack_chk_guard);
180#endif
181
182struct mips_frame_info {
183 void *func;
184 unsigned long func_size;
185 int frame_size;
186 int pc_offset;
187};
188
189#define J_TARGET(pc,target) \
190 (((unsigned long)(pc) & 0xf0000000) | ((target) << 2))
191
192static inline int is_ra_save_ins(union mips_instruction *ip)
193{
194#ifdef CONFIG_CPU_MICROMIPS
195 union mips_instruction mmi;
196
197 /*
198 * swsp ra,offset
199 * swm16 reglist,offset(sp)
200 * swm32 reglist,offset(sp)
201 * sw32 ra,offset(sp)
202 * jradiussp - NOT SUPPORTED
203 *
204 * microMIPS is way more fun...
205 */
206 if (mm_insn_16bit(ip->halfword[0])) {
207 mmi.word = (ip->halfword[0] << 16);
208 return (mmi.mm16_r5_format.opcode == mm_swsp16_op &&
209 mmi.mm16_r5_format.rt == 31) ||
210 (mmi.mm16_m_format.opcode == mm_pool16c_op &&
211 mmi.mm16_m_format.func == mm_swm16_op);
212 }
213 else {
214 mmi.halfword[0] = ip->halfword[1];
215 mmi.halfword[1] = ip->halfword[0];
216 return (mmi.mm_m_format.opcode == mm_pool32b_op &&
217 mmi.mm_m_format.rd > 9 &&
218 mmi.mm_m_format.base == 29 &&
219 mmi.mm_m_format.func == mm_swm32_func) ||
220 (mmi.i_format.opcode == mm_sw32_op &&
221 mmi.i_format.rs == 29 &&
222 mmi.i_format.rt == 31);
223 }
224#else
225 /* sw / sd $ra, offset($sp) */
226 return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) &&
227 ip->i_format.rs == 29 &&
228 ip->i_format.rt == 31;
229#endif
230}
231
232static inline int is_jump_ins(union mips_instruction *ip)
233{
234#ifdef CONFIG_CPU_MICROMIPS
235 /*
236 * jr16,jrc,jalr16,jalr16
237 * jal
238 * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb
239 * jraddiusp - NOT SUPPORTED
240 *
241 * microMIPS is kind of more fun...
242 */
243 union mips_instruction mmi;
244
245 mmi.word = (ip->halfword[0] << 16);
246
247 if ((mmi.mm16_r5_format.opcode == mm_pool16c_op &&
248 (mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) ||
249 ip->j_format.opcode == mm_jal32_op)
250 return 1;
251 if (ip->r_format.opcode != mm_pool32a_op ||
252 ip->r_format.func != mm_pool32axf_op)
253 return 0;
254 return ((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op;
255#else
256 if (ip->j_format.opcode == j_op)
257 return 1;
258 if (ip->j_format.opcode == jal_op)
259 return 1;
260 if (ip->r_format.opcode != spec_op)
261 return 0;
262 return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;
263#endif
264}
265
266static inline int is_sp_move_ins(union mips_instruction *ip)
267{
268#ifdef CONFIG_CPU_MICROMIPS
269 /*
270 * addiusp -imm
271 * addius5 sp,-imm
272 * addiu32 sp,sp,-imm
273 * jradiussp - NOT SUPPORTED
274 *
275 * microMIPS is not more fun...
276 */
277 if (mm_insn_16bit(ip->halfword[0])) {
278 union mips_instruction mmi;
279
280 mmi.word = (ip->halfword[0] << 16);
281 return (mmi.mm16_r3_format.opcode == mm_pool16d_op &&
282 mmi.mm16_r3_format.simmediate && mm_addiusp_func) ||
283 (mmi.mm16_r5_format.opcode == mm_pool16d_op &&
284 mmi.mm16_r5_format.rt == 29);
285 }
286 return ip->mm_i_format.opcode == mm_addiu32_op &&
287 ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29;
288#else
289 /* addiu/daddiu sp,sp,-imm */
290 if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
291 return 0;
292 if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
293 return 1;
294#endif
295 return 0;
296}
297
298static int get_frame_info(struct mips_frame_info *info)
299{
300#ifdef CONFIG_CPU_MICROMIPS
301 union mips_instruction *ip = (void *) (((char *) info->func) - 1);
302#else
303 union mips_instruction *ip = info->func;
304#endif
305 unsigned max_insns = info->func_size / sizeof(union mips_instruction);
306 unsigned i;
307
308 info->pc_offset = -1;
309 info->frame_size = 0;
310
311 if (!ip)
312 goto err;
313
314 if (max_insns == 0)
315 max_insns = 128U; /* unknown function size */
316 max_insns = min(128U, max_insns);
317
318 for (i = 0; i < max_insns; i++, ip++) {
319
320 if (is_jump_ins(ip))
321 break;
322 if (!info->frame_size) {
323 if (is_sp_move_ins(ip))
324 {
325#ifdef CONFIG_CPU_MICROMIPS
326 if (mm_insn_16bit(ip->halfword[0]))
327 {
328 unsigned short tmp;
329
330 if (ip->halfword[0] & mm_addiusp_func)
331 {
332 tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2);
333 info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0));
334 } else {
335 tmp = (ip->halfword[0] >> 1);
336 info->frame_size = -(signed short)(tmp & 0xf);
337 }
338 ip = (void *) &ip->halfword[1];
339 ip--;
340 } else
341#endif
342 info->frame_size = - ip->i_format.simmediate;
343 }
344 continue;
345 }
346 if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
347 info->pc_offset =
348 ip->i_format.simmediate / sizeof(long);
349 break;
350 }
351 }
352 if (info->frame_size && info->pc_offset >= 0) /* nested */
353 return 0;
354 if (info->pc_offset < 0) /* leaf */
355 return 1;
356 /* prologue seems boggus... */
357err:
358 return -1;
359}
360
361static struct mips_frame_info schedule_mfi __read_mostly;
362
363#ifdef CONFIG_KALLSYMS
364static unsigned long get___schedule_addr(void)
365{
366 return kallsyms_lookup_name("__schedule");
367}
368#else
369static unsigned long get___schedule_addr(void)
370{
371 union mips_instruction *ip = (void *)schedule;
372 int max_insns = 8;
373 int i;
374
375 for (i = 0; i < max_insns; i++, ip++) {
376 if (ip->j_format.opcode == j_op)
377 return J_TARGET(ip, ip->j_format.target);
378 }
379 return 0;
380}
381#endif
382
383static int __init frame_info_init(void)
384{
385 unsigned long size = 0;
386#ifdef CONFIG_KALLSYMS
387 unsigned long ofs;
388#endif
389 unsigned long addr;
390
391 addr = get___schedule_addr();
392 if (!addr)
393 addr = (unsigned long)schedule;
394
395#ifdef CONFIG_KALLSYMS
396 kallsyms_lookup_size_offset(addr, &size, &ofs);
397#endif
398 schedule_mfi.func = (void *)addr;
399 schedule_mfi.func_size = size;
400
401 get_frame_info(&schedule_mfi);
402
403 /*
404 * Without schedule() frame info, result given by
405 * thread_saved_pc() and get_wchan() are not reliable.
406 */
407 if (schedule_mfi.pc_offset < 0)
408 printk("Can't analyze schedule() prologue at %p\n", schedule);
409
410 return 0;
411}
412
413arch_initcall(frame_info_init);
414
415/*
416 * Return saved PC of a blocked thread.
417 */
418unsigned long thread_saved_pc(struct task_struct *tsk)
419{
420 struct thread_struct *t = &tsk->thread;
421
422 /* New born processes are a special case */
423 if (t->reg31 == (unsigned long) ret_from_fork)
424 return t->reg31;
425 if (schedule_mfi.pc_offset < 0)
426 return 0;
427 return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
428}
429
430
431#ifdef CONFIG_KALLSYMS
432/* generic stack unwinding function */
433unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
434 unsigned long *sp,
435 unsigned long pc,
436 unsigned long *ra)
437{
438 struct mips_frame_info info;
439 unsigned long size, ofs;
440 int leaf;
441 extern void ret_from_irq(void);
442 extern void ret_from_exception(void);
443
444 if (!stack_page)
445 return 0;
446
447 /*
448 * If we reached the bottom of interrupt context,
449 * return saved pc in pt_regs.
450 */
451 if (pc == (unsigned long)ret_from_irq ||
452 pc == (unsigned long)ret_from_exception) {
453 struct pt_regs *regs;
454 if (*sp >= stack_page &&
455 *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {
456 regs = (struct pt_regs *)*sp;
457 pc = regs->cp0_epc;
458 if (__kernel_text_address(pc)) {
459 *sp = regs->regs[29];
460 *ra = regs->regs[31];
461 return pc;
462 }
463 }
464 return 0;
465 }
466 if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
467 return 0;
468 /*
469 * Return ra if an exception occurred at the first instruction
470 */
471 if (unlikely(ofs == 0)) {
472 pc = *ra;
473 *ra = 0;
474 return pc;
475 }
476
477 info.func = (void *)(pc - ofs);
478 info.func_size = ofs; /* analyze from start to ofs */
479 leaf = get_frame_info(&info);
480 if (leaf < 0)
481 return 0;
482
483 if (*sp < stack_page ||
484 *sp + info.frame_size > stack_page + THREAD_SIZE - 32)
485 return 0;
486
487 if (leaf)
488 /*
489 * For some extreme cases, get_frame_info() can
490 * consider wrongly a nested function as a leaf
491 * one. In that cases avoid to return always the
492 * same value.
493 */
494 pc = pc != *ra ? *ra : 0;
495 else
496 pc = ((unsigned long *)(*sp))[info.pc_offset];
497
498 *sp += info.frame_size;
499 *ra = 0;
500 return __kernel_text_address(pc) ? pc : 0;
501}
502EXPORT_SYMBOL(unwind_stack_by_address);
503
504/* used by show_backtrace() */
505unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
506 unsigned long pc, unsigned long *ra)
507{
508 unsigned long stack_page = (unsigned long)task_stack_page(task);
509 return unwind_stack_by_address(stack_page, sp, pc, ra);
510}
511#endif
512
513/*
514 * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
515 */
516unsigned long get_wchan(struct task_struct *task)
517{
518 unsigned long pc = 0;
519#ifdef CONFIG_KALLSYMS
520 unsigned long sp;
521 unsigned long ra = 0;
522#endif
523
524 if (!task || task == current || task->state == TASK_RUNNING)
525 goto out;
526 if (!task_stack_page(task))
527 goto out;
528
529 pc = thread_saved_pc(task);
530
531#ifdef CONFIG_KALLSYMS
532 sp = task->thread.reg29 + schedule_mfi.frame_size;
533
534 while (in_sched_functions(pc))
535 pc = unwind_stack(task, &sp, pc, &ra);
536#endif
537
538out:
539 return pc;
540}
541
542/*
543 * Don't forget that the stack pointer must be aligned on a 8 bytes
544 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
545 */
546unsigned long arch_align_stack(unsigned long sp)
547{
548 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
549 sp -= get_random_int() & ~PAGE_MASK;
550
551 return sp & ALMASK;
552}
553
554static void arch_dump_stack(void *info)
555{
556 struct pt_regs *regs;
557
558 regs = get_irq_regs();
559
560 if (regs)
561 show_regs(regs);
562
563 dump_stack();
564}
565
566void arch_trigger_all_cpu_backtrace(bool include_self)
567{
568 smp_call_function(arch_dump_stack, NULL, 1);
569}
570
571int mips_get_process_fp_mode(struct task_struct *task)
572{
573 int value = 0;
574
575 if (!test_tsk_thread_flag(task, TIF_32BIT_FPREGS))
576 value |= PR_FP_MODE_FR;
577 if (test_tsk_thread_flag(task, TIF_HYBRID_FPREGS))
578 value |= PR_FP_MODE_FRE;
579
580 return value;
581}
582
583int mips_set_process_fp_mode(struct task_struct *task, unsigned int value)
584{
585 const unsigned int known_bits = PR_FP_MODE_FR | PR_FP_MODE_FRE;
586 unsigned long switch_count;
587 struct task_struct *t;
588
589 /* Check the value is valid */
590 if (value & ~known_bits)
591 return -EOPNOTSUPP;
592
593 /* Avoid inadvertently triggering emulation */
594 if ((value & PR_FP_MODE_FR) && cpu_has_fpu &&
595 !(current_cpu_data.fpu_id & MIPS_FPIR_F64))
596 return -EOPNOTSUPP;
597 if ((value & PR_FP_MODE_FRE) && cpu_has_fpu && !cpu_has_fre)
598 return -EOPNOTSUPP;
599
600 /* FR = 0 not supported in MIPS R6 */
601 if (!(value & PR_FP_MODE_FR) && cpu_has_fpu && cpu_has_mips_r6)
602 return -EOPNOTSUPP;
603
604 /* Save FP & vector context, then disable FPU & MSA */
605 if (task->signal == current->signal)
606 lose_fpu(1);
607
608 /* Prevent any threads from obtaining live FP context */
609 atomic_set(&task->mm->context.fp_mode_switching, 1);
610 smp_mb__after_atomic();
611
612 /*
613 * If there are multiple online CPUs then wait until all threads whose
614 * FP mode is about to change have been context switched. This approach
615 * allows us to only worry about whether an FP mode switch is in
616 * progress when FP is first used in a tasks time slice. Pretty much all
617 * of the mode switch overhead can thus be confined to cases where mode
618 * switches are actually occurring. That is, to here. However for the
619 * thread performing the mode switch it may take a while...
620 */
621 if (num_online_cpus() > 1) {
622 spin_lock_irq(&task->sighand->siglock);
623
624 for_each_thread(task, t) {
625 if (t == current)
626 continue;
627
628 switch_count = t->nvcsw + t->nivcsw;
629
630 do {
631 spin_unlock_irq(&task->sighand->siglock);
632 cond_resched();
633 spin_lock_irq(&task->sighand->siglock);
634 } while ((t->nvcsw + t->nivcsw) == switch_count);
635 }
636
637 spin_unlock_irq(&task->sighand->siglock);
638 }
639
640 /*
641 * There are now no threads of the process with live FP context, so it
642 * is safe to proceed with the FP mode switch.
643 */
644 for_each_thread(task, t) {
645 /* Update desired FP register width */
646 if (value & PR_FP_MODE_FR) {
647 clear_tsk_thread_flag(t, TIF_32BIT_FPREGS);
648 } else {
649 set_tsk_thread_flag(t, TIF_32BIT_FPREGS);
650 clear_tsk_thread_flag(t, TIF_MSA_CTX_LIVE);
651 }
652
653 /* Update desired FP single layout */
654 if (value & PR_FP_MODE_FRE)
655 set_tsk_thread_flag(t, TIF_HYBRID_FPREGS);
656 else
657 clear_tsk_thread_flag(t, TIF_HYBRID_FPREGS);
658 }
659
660 /* Allow threads to use FP again */
661 atomic_set(&task->mm->context.fp_mode_switching, 0);
662
663 return 0;
664}