1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * arch/sh/kernel/process.c
4 *
5 * This file handles the architecture-dependent parts of process handling..
6 *
7 * Copyright (C) 1995 Linus Torvalds
8 *
9 * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
10 * Copyright (C) 2006 Lineo Solutions Inc. support SH4A UBC
11 * Copyright (C) 2002 - 2008 Paul Mundt
12 */
13 #include <linux/module.h>
14 #include <linux/mm.h>
15 #include <linux/sched/debug.h>
16 #include <linux/sched/task.h>
17 #include <linux/sched/task_stack.h>
18 #include <linux/slab.h>
19 #include <linux/elfcore.h>
20 #include <linux/fs.h>
21 #include <linux/ftrace.h>
22 #include <linux/hw_breakpoint.h>
23 #include <linux/prefetch.h>
24 #include <linux/stackprotector.h>
25 #include <linux/uaccess.h>
26 #include <asm/mmu_context.h>
27 #include <asm/fpu.h>
28 #include <asm/syscalls.h>
29 #include <asm/switch_to.h>
30
show_regs(struct pt_regs * regs)31 void show_regs(struct pt_regs * regs)
32 {
33 pr_info("\n");
34 show_regs_print_info(KERN_DEFAULT);
35
36 pr_info("PC is at %pS\n", (void *)instruction_pointer(regs));
37 pr_info("PR is at %pS\n", (void *)regs->pr);
38
39 pr_info("PC : %08lx SP : %08lx SR : %08lx ", regs->pc,
40 regs->regs[15], regs->sr);
41 #ifdef CONFIG_MMU
42 pr_cont("TEA : %08x\n", __raw_readl(MMU_TEA));
43 #else
44 pr_cont("\n");
45 #endif
46
47 pr_info("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n",
48 regs->regs[0], regs->regs[1], regs->regs[2], regs->regs[3]);
49 pr_info("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n",
50 regs->regs[4], regs->regs[5], regs->regs[6], regs->regs[7]);
51 pr_info("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n",
52 regs->regs[8], regs->regs[9], regs->regs[10], regs->regs[11]);
53 pr_info("R12 : %08lx R13 : %08lx R14 : %08lx\n",
54 regs->regs[12], regs->regs[13], regs->regs[14]);
55 pr_info("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n",
56 regs->mach, regs->macl, regs->gbr, regs->pr);
57
58 show_trace(NULL, (unsigned long *)regs->regs[15], regs, KERN_DEFAULT);
59 show_code(regs);
60 }
61
start_thread(struct pt_regs * regs,unsigned long new_pc,unsigned long new_sp)62 void start_thread(struct pt_regs *regs, unsigned long new_pc,
63 unsigned long new_sp)
64 {
65 regs->pr = 0;
66 regs->sr = SR_FD;
67 regs->pc = new_pc;
68 regs->regs[15] = new_sp;
69
70 free_thread_xstate(current);
71 }
72 EXPORT_SYMBOL(start_thread);
73
flush_thread(void)74 void flush_thread(void)
75 {
76 struct task_struct *tsk = current;
77
78 flush_ptrace_hw_breakpoint(tsk);
79
80 #if defined(CONFIG_SH_FPU)
81 /* Forget lazy FPU state */
82 clear_fpu(tsk, task_pt_regs(tsk));
83 clear_used_math();
84 #endif
85 }
86
release_thread(struct task_struct * dead_task)87 void release_thread(struct task_struct *dead_task)
88 {
89 /* do nothing */
90 }
91
92 asmlinkage void ret_from_fork(void);
93 asmlinkage void ret_from_kernel_thread(void);
94
copy_thread(unsigned long clone_flags,unsigned long usp,unsigned long arg,struct task_struct * p,unsigned long tls)95 int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
96 struct task_struct *p, unsigned long tls)
97 {
98 struct thread_info *ti = task_thread_info(p);
99 struct pt_regs *childregs;
100
101 #if defined(CONFIG_SH_DSP)
102 struct task_struct *tsk = current;
103
104 if (is_dsp_enabled(tsk)) {
105 /* We can use the __save_dsp or just copy the struct:
106 * __save_dsp(p);
107 * p->thread.dsp_status.status |= SR_DSP
108 */
109 p->thread.dsp_status = tsk->thread.dsp_status;
110 }
111 #endif
112
113 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
114
115 childregs = task_pt_regs(p);
116 p->thread.sp = (unsigned long) childregs;
117 if (unlikely(p->flags & PF_KTHREAD)) {
118 memset(childregs, 0, sizeof(struct pt_regs));
119 p->thread.pc = (unsigned long) ret_from_kernel_thread;
120 childregs->regs[4] = arg;
121 childregs->regs[5] = usp;
122 childregs->sr = SR_MD;
123 #if defined(CONFIG_SH_FPU)
124 childregs->sr |= SR_FD;
125 #endif
126 ti->addr_limit = KERNEL_DS;
127 ti->status &= ~TS_USEDFPU;
128 p->thread.fpu_counter = 0;
129 return 0;
130 }
131 *childregs = *current_pt_regs();
132
133 if (usp)
134 childregs->regs[15] = usp;
135 ti->addr_limit = USER_DS;
136
137 if (clone_flags & CLONE_SETTLS)
138 childregs->gbr = tls;
139
140 childregs->regs[0] = 0; /* Set return value for child */
141 p->thread.pc = (unsigned long) ret_from_fork;
142 return 0;
143 }
144
145 /*
146 * switch_to(x,y) should switch tasks from x to y.
147 *
148 */
149 __notrace_funcgraph struct task_struct *
__switch_to(struct task_struct * prev,struct task_struct * next)150 __switch_to(struct task_struct *prev, struct task_struct *next)
151 {
152 struct thread_struct *next_t = &next->thread;
153
154 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_SMP)
155 __stack_chk_guard = next->stack_canary;
156 #endif
157
158 unlazy_fpu(prev, task_pt_regs(prev));
159
160 /* we're going to use this soon, after a few expensive things */
161 if (next->thread.fpu_counter > 5)
162 prefetch(next_t->xstate);
163
164 #ifdef CONFIG_MMU
165 /*
166 * Restore the kernel mode register
167 * k7 (r7_bank1)
168 */
169 asm volatile("ldc %0, r7_bank"
170 : /* no output */
171 : "r" (task_thread_info(next)));
172 #endif
173
174 /*
175 * If the task has used fpu the last 5 timeslices, just do a full
176 * restore of the math state immediately to avoid the trap; the
177 * chances of needing FPU soon are obviously high now
178 */
179 if (next->thread.fpu_counter > 5)
180 __fpu_state_restore();
181
182 return prev;
183 }
184
get_wchan(struct task_struct * p)185 unsigned long get_wchan(struct task_struct *p)
186 {
187 unsigned long pc;
188
189 if (!p || p == current || p->state == TASK_RUNNING)
190 return 0;
191
192 /*
193 * The same comment as on the Alpha applies here, too ...
194 */
195 pc = thread_saved_pc(p);
196
197 #ifdef CONFIG_FRAME_POINTER
198 if (in_sched_functions(pc)) {
199 unsigned long schedule_frame = (unsigned long)p->thread.sp;
200 return ((unsigned long *)schedule_frame)[21];
201 }
202 #endif
203
204 return pc;
205 }
206
