1 /*
2 * arch/sh/kernel/process.c
3 *
4 * This file handles the architecture-dependent parts of process handling..
5 *
6 * Copyright (C) 1995 Linus Torvalds
7 *
8 * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
9 * Copyright (C) 2006 Lineo Solutions Inc. support SH4A UBC
10 * Copyright (C) 2002 - 2008 Paul Mundt
11 *
12 * This file is subject to the terms and conditions of the GNU General Public
13 * License. See the file "COPYING" in the main directory of this archive
14 * for more details.
15 */
16 #include <linux/module.h>
17 #include <linux/mm.h>
18 #include <linux/sched/debug.h>
19 #include <linux/sched/task.h>
20 #include <linux/sched/task_stack.h>
21 #include <linux/slab.h>
22 #include <linux/elfcore.h>
23 #include <linux/kallsyms.h>
24 #include <linux/fs.h>
25 #include <linux/ftrace.h>
26 #include <linux/hw_breakpoint.h>
27 #include <linux/prefetch.h>
28 #include <linux/stackprotector.h>
29 #include <linux/uaccess.h>
30 #include <asm/mmu_context.h>
31 #include <asm/fpu.h>
32 #include <asm/syscalls.h>
33 #include <asm/switch_to.h>
34
35 void show_regs(struct pt_regs * regs)
36 {
37 printk("\n");
38 show_regs_print_info(KERN_DEFAULT);
39
40 print_symbol("PC is at %s\n", instruction_pointer(regs));
41 print_symbol("PR is at %s\n", regs->pr);
42
43 printk("PC : %08lx SP : %08lx SR : %08lx ",
44 regs->pc, regs->regs[15], regs->sr);
45 #ifdef CONFIG_MMU
46 printk("TEA : %08x\n", __raw_readl(MMU_TEA));
47 #else
48 printk("\n");
49 #endif
50
51 printk("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n",
52 regs->regs[0],regs->regs[1],
53 regs->regs[2],regs->regs[3]);
54 printk("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n",
55 regs->regs[4],regs->regs[5],
56 regs->regs[6],regs->regs[7]);
57 printk("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n",
58 regs->regs[8],regs->regs[9],
59 regs->regs[10],regs->regs[11]);
60 printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
61 regs->regs[12],regs->regs[13],
62 regs->regs[14]);
63 printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n",
64 regs->mach, regs->macl, regs->gbr, regs->pr);
65
66 show_trace(NULL, (unsigned long *)regs->regs[15], regs);
67 show_code(regs);
68 }
69
70 void start_thread(struct pt_regs *regs, unsigned long new_pc,
71 unsigned long new_sp)
72 {
73 regs->pr = 0;
74 regs->sr = SR_FD;
75 regs->pc = new_pc;
76 regs->regs[15] = new_sp;
77
78 free_thread_xstate(current);
79 }
80 EXPORT_SYMBOL(start_thread);
81
82 void flush_thread(void)
83 {
84 struct task_struct *tsk = current;
85
86 flush_ptrace_hw_breakpoint(tsk);
87
88 #if defined(CONFIG_SH_FPU)
89 /* Forget lazy FPU state */
90 clear_fpu(tsk, task_pt_regs(tsk));
91 clear_used_math();
92 #endif
93 }
94
95 void release_thread(struct task_struct *dead_task)
96 {
97 /* do nothing */
98 }
99
100 /* Fill in the fpu structure for a core dump.. */
101 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
102 {
103 int fpvalid = 0;
104
105 #if defined(CONFIG_SH_FPU)
106 struct task_struct *tsk = current;
107
108 fpvalid = !!tsk_used_math(tsk);
109 if (fpvalid)
110 fpvalid = !fpregs_get(tsk, NULL, 0,
111 sizeof(struct user_fpu_struct),
112 fpu, NULL);
113 #endif
114
115 return fpvalid;
116 }
117 EXPORT_SYMBOL(dump_fpu);
118
119 asmlinkage void ret_from_fork(void);
120 asmlinkage void ret_from_kernel_thread(void);
121
122 int copy_thread(unsigned long clone_flags, unsigned long usp,
123 unsigned long arg, struct task_struct *p)
124 {
125 struct thread_info *ti = task_thread_info(p);
126 struct pt_regs *childregs;
127
128 #if defined(CONFIG_SH_DSP)
129 struct task_struct *tsk = current;
130
131 if (is_dsp_enabled(tsk)) {
132 /* We can use the __save_dsp or just copy the struct:
133 * __save_dsp(p);
134 * p->thread.dsp_status.status |= SR_DSP
135 */
136 p->thread.dsp_status = tsk->thread.dsp_status;
137 }
138 #endif
139
140 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
141
142 childregs = task_pt_regs(p);
143 p->thread.sp = (unsigned long) childregs;
144 if (unlikely(p->flags & PF_KTHREAD)) {
145 memset(childregs, 0, sizeof(struct pt_regs));
146 p->thread.pc = (unsigned long) ret_from_kernel_thread;
147 childregs->regs[4] = arg;
148 childregs->regs[5] = usp;
149 childregs->sr = SR_MD;
150 #if defined(CONFIG_SH_FPU)
151 childregs->sr |= SR_FD;
152 #endif
153 ti->addr_limit = KERNEL_DS;
154 ti->status &= ~TS_USEDFPU;
155 p->thread.fpu_counter = 0;
156 return 0;
157 }
158 *childregs = *current_pt_regs();
159
160 if (usp)
161 childregs->regs[15] = usp;
162 ti->addr_limit = USER_DS;
163
164 if (clone_flags & CLONE_SETTLS)
165 childregs->gbr = childregs->regs[0];
166
167 childregs->regs[0] = 0; /* Set return value for child */
168 p->thread.pc = (unsigned long) ret_from_fork;
169 return 0;
170 }
171
172 /*
173 * switch_to(x,y) should switch tasks from x to y.
174 *
175 */
176 __notrace_funcgraph struct task_struct *
177 __switch_to(struct task_struct *prev, struct task_struct *next)
178 {
179 struct thread_struct *next_t = &next->thread;
180
181 #if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
182 __stack_chk_guard = next->stack_canary;
183 #endif
184
185 unlazy_fpu(prev, task_pt_regs(prev));
186
187 /* we're going to use this soon, after a few expensive things */
188 if (next->thread.fpu_counter > 5)
189 prefetch(next_t->xstate);
190
191 #ifdef CONFIG_MMU
192 /*
193 * Restore the kernel mode register
194 * k7 (r7_bank1)
195 */
196 asm volatile("ldc %0, r7_bank"
197 : /* no output */
198 : "r" (task_thread_info(next)));
199 #endif
200
201 /*
202 * If the task has used fpu the last 5 timeslices, just do a full
203 * restore of the math state immediately to avoid the trap; the
204 * chances of needing FPU soon are obviously high now
205 */
206 if (next->thread.fpu_counter > 5)
207 __fpu_state_restore();
208
209 return prev;
210 }
211
212 unsigned long get_wchan(struct task_struct *p)
213 {
214 unsigned long pc;
215
216 if (!p || p == current || p->state == TASK_RUNNING)
217 return 0;
218
219 /*
220 * The same comment as on the Alpha applies here, too ...
221 */
222 pc = thread_saved_pc(p);
223
224 #ifdef CONFIG_FRAME_POINTER
225 if (in_sched_functions(pc)) {
226 unsigned long schedule_frame = (unsigned long)p->thread.sp;
227 return ((unsigned long *)schedule_frame)[21];
228 }
229 #endif
230
231 return pc;
232 }
233
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