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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
31void 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
62void 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}
72EXPORT_SYMBOL(start_thread);
73
74void 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
87asmlinkage void ret_from_fork(void);
88asmlinkage void ret_from_kernel_thread(void);
89
90int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
91{
92 unsigned long clone_flags = args->flags;
93 unsigned long usp = args->stack;
94 unsigned long tls = args->tls;
95 struct thread_info *ti = task_thread_info(p);
96 struct pt_regs *childregs;
97
98#if defined(CONFIG_SH_DSP)
99 struct task_struct *tsk = current;
100
101 if (is_dsp_enabled(tsk)) {
102 /* We can use the __save_dsp or just copy the struct:
103 * __save_dsp(p);
104 * p->thread.dsp_status.status |= SR_DSP
105 */
106 p->thread.dsp_status = tsk->thread.dsp_status;
107 }
108#endif
109
110 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
111
112 childregs = task_pt_regs(p);
113 p->thread.sp = (unsigned long) childregs;
114 if (unlikely(args->fn)) {
115 memset(childregs, 0, sizeof(struct pt_regs));
116 p->thread.pc = (unsigned long) ret_from_kernel_thread;
117 childregs->regs[4] = (unsigned long) args->fn_arg;
118 childregs->regs[5] = (unsigned long) args->fn;
119 childregs->sr = SR_MD;
120#if defined(CONFIG_SH_FPU)
121 childregs->sr |= SR_FD;
122#endif
123 ti->status &= ~TS_USEDFPU;
124 p->thread.fpu_counter = 0;
125 return 0;
126 }
127 *childregs = *current_pt_regs();
128
129 if (usp)
130 childregs->regs[15] = usp;
131
132 if (clone_flags & CLONE_SETTLS)
133 childregs->gbr = tls;
134
135 childregs->regs[0] = 0; /* Set return value for child */
136 p->thread.pc = (unsigned long) ret_from_fork;
137 return 0;
138}
139
140/*
141 * switch_to(x,y) should switch tasks from x to y.
142 *
143 */
144__notrace_funcgraph struct task_struct *
145__switch_to(struct task_struct *prev, struct task_struct *next)
146{
147 struct thread_struct *next_t = &next->thread;
148
149#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_SMP)
150 __stack_chk_guard = next->stack_canary;
151#endif
152
153 unlazy_fpu(prev, task_pt_regs(prev));
154
155 /* we're going to use this soon, after a few expensive things */
156 if (next->thread.fpu_counter > 5)
157 prefetch(next_t->xstate);
158
159#ifdef CONFIG_MMU
160 /*
161 * Restore the kernel mode register
162 * k7 (r7_bank1)
163 */
164 asm volatile("ldc %0, r7_bank"
165 : /* no output */
166 : "r" (task_thread_info(next)));
167#endif
168
169 /*
170 * If the task has used fpu the last 5 timeslices, just do a full
171 * restore of the math state immediately to avoid the trap; the
172 * chances of needing FPU soon are obviously high now
173 */
174 if (next->thread.fpu_counter > 5)
175 __fpu_state_restore();
176
177 return prev;
178}
179
180unsigned long __get_wchan(struct task_struct *p)
181{
182 unsigned long pc;
183
184 /*
185 * The same comment as on the Alpha applies here, too ...
186 */
187 pc = thread_saved_pc(p);
188
189#ifdef CONFIG_FRAME_POINTER
190 if (in_sched_functions(pc)) {
191 unsigned long schedule_frame = (unsigned long)p->thread.sp;
192 return ((unsigned long *)schedule_frame)[21];
193 }
194#endif
195
196 return pc;
197}
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/slab.h>
19#include <linux/elfcore.h>
20#include <linux/kallsyms.h>
21#include <linux/fs.h>
22#include <linux/ftrace.h>
23#include <linux/hw_breakpoint.h>
24#include <linux/prefetch.h>
25#include <asm/uaccess.h>
26#include <asm/mmu_context.h>
27#include <asm/system.h>
28#include <asm/fpu.h>
29#include <asm/syscalls.h>
30
31void show_regs(struct pt_regs * regs)
32{
33 printk("\n");
34 printk("Pid : %d, Comm: \t\t%s\n", task_pid_nr(current), current->comm);
35 printk("CPU : %d \t\t%s (%s %.*s)\n\n",
36 smp_processor_id(), print_tainted(), init_utsname()->release,
37 (int)strcspn(init_utsname()->version, " "),
38 init_utsname()->version);
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/*
71 * Create a kernel thread
72 */
73ATTRIB_NORET void kernel_thread_helper(void *arg, int (*fn)(void *))
74{
75 do_exit(fn(arg));
76}
77
78/* Don't use this in BL=1(cli). Or else, CPU resets! */
79int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
80{
81 struct pt_regs regs;
82 int pid;
83
84 memset(®s, 0, sizeof(regs));
85 regs.regs[4] = (unsigned long)arg;
86 regs.regs[5] = (unsigned long)fn;
87
88 regs.pc = (unsigned long)kernel_thread_helper;
89 regs.sr = SR_MD;
90#if defined(CONFIG_SH_FPU)
91 regs.sr |= SR_FD;
92#endif
93
94 /* Ok, create the new process.. */
95 pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
96 ®s, 0, NULL, NULL);
97
98 return pid;
99}
100EXPORT_SYMBOL(kernel_thread);
101
102void start_thread(struct pt_regs *regs, unsigned long new_pc,
103 unsigned long new_sp)
104{
105 regs->pr = 0;
106 regs->sr = SR_FD;
107 regs->pc = new_pc;
108 regs->regs[15] = new_sp;
109
110 free_thread_xstate(current);
111}
112EXPORT_SYMBOL(start_thread);
113
114/*
115 * Free current thread data structures etc..
116 */
117void exit_thread(void)
118{
119}
120
121void flush_thread(void)
122{
123 struct task_struct *tsk = current;
124
125 flush_ptrace_hw_breakpoint(tsk);
126
127#if defined(CONFIG_SH_FPU)
128 /* Forget lazy FPU state */
129 clear_fpu(tsk, task_pt_regs(tsk));
130 clear_used_math();
131#endif
132}
133
134void release_thread(struct task_struct *dead_task)
135{
136 /* do nothing */
137}
138
139/* Fill in the fpu structure for a core dump.. */
140int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
141{
142 int fpvalid = 0;
143
144#if defined(CONFIG_SH_FPU)
145 struct task_struct *tsk = current;
146
147 fpvalid = !!tsk_used_math(tsk);
148 if (fpvalid)
149 fpvalid = !fpregs_get(tsk, NULL, 0,
150 sizeof(struct user_fpu_struct),
151 fpu, NULL);
152#endif
153
154 return fpvalid;
155}
156EXPORT_SYMBOL(dump_fpu);
157
158/*
159 * This gets called before we allocate a new thread and copy
160 * the current task into it.
161 */
162void prepare_to_copy(struct task_struct *tsk)
163{
164 unlazy_fpu(tsk, task_pt_regs(tsk));
165}
166
167asmlinkage void ret_from_fork(void);
168
169int copy_thread(unsigned long clone_flags, unsigned long usp,
170 unsigned long unused,
171 struct task_struct *p, struct pt_regs *regs)
172{
173 struct thread_info *ti = task_thread_info(p);
174 struct pt_regs *childregs;
175
176#if defined(CONFIG_SH_DSP)
177 struct task_struct *tsk = current;
178
179 if (is_dsp_enabled(tsk)) {
180 /* We can use the __save_dsp or just copy the struct:
181 * __save_dsp(p);
182 * p->thread.dsp_status.status |= SR_DSP
183 */
184 p->thread.dsp_status = tsk->thread.dsp_status;
185 }
186#endif
187
188 childregs = task_pt_regs(p);
189 *childregs = *regs;
190
191 if (user_mode(regs)) {
192 childregs->regs[15] = usp;
193 ti->addr_limit = USER_DS;
194 } else {
195 childregs->regs[15] = (unsigned long)childregs;
196 ti->addr_limit = KERNEL_DS;
197 ti->status &= ~TS_USEDFPU;
198 p->fpu_counter = 0;
199 }
200
201 if (clone_flags & CLONE_SETTLS)
202 childregs->gbr = childregs->regs[0];
203
204 childregs->regs[0] = 0; /* Set return value for child */
205
206 p->thread.sp = (unsigned long) childregs;
207 p->thread.pc = (unsigned long) ret_from_fork;
208
209 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
210
211 return 0;
212}
213
214/*
215 * switch_to(x,y) should switch tasks from x to y.
216 *
217 */
218__notrace_funcgraph struct task_struct *
219__switch_to(struct task_struct *prev, struct task_struct *next)
220{
221 struct thread_struct *next_t = &next->thread;
222
223 unlazy_fpu(prev, task_pt_regs(prev));
224
225 /* we're going to use this soon, after a few expensive things */
226 if (next->fpu_counter > 5)
227 prefetch(next_t->xstate);
228
229#ifdef CONFIG_MMU
230 /*
231 * Restore the kernel mode register
232 * k7 (r7_bank1)
233 */
234 asm volatile("ldc %0, r7_bank"
235 : /* no output */
236 : "r" (task_thread_info(next)));
237#endif
238
239 /*
240 * If the task has used fpu the last 5 timeslices, just do a full
241 * restore of the math state immediately to avoid the trap; the
242 * chances of needing FPU soon are obviously high now
243 */
244 if (next->fpu_counter > 5)
245 __fpu_state_restore();
246
247 return prev;
248}
249
250asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
251 unsigned long r6, unsigned long r7,
252 struct pt_regs __regs)
253{
254#ifdef CONFIG_MMU
255 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
256 return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL);
257#else
258 /* fork almost works, enough to trick you into looking elsewhere :-( */
259 return -EINVAL;
260#endif
261}
262
263asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
264 unsigned long parent_tidptr,
265 unsigned long child_tidptr,
266 struct pt_regs __regs)
267{
268 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
269 if (!newsp)
270 newsp = regs->regs[15];
271 return do_fork(clone_flags, newsp, regs, 0,
272 (int __user *)parent_tidptr,
273 (int __user *)child_tidptr);
274}
275
276/*
277 * This is trivial, and on the face of it looks like it
278 * could equally well be done in user mode.
279 *
280 * Not so, for quite unobvious reasons - register pressure.
281 * In user mode vfork() cannot have a stack frame, and if
282 * done by calling the "clone()" system call directly, you
283 * do not have enough call-clobbered registers to hold all
284 * the information you need.
285 */
286asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
287 unsigned long r6, unsigned long r7,
288 struct pt_regs __regs)
289{
290 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
291 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs,
292 0, NULL, NULL);
293}
294
295/*
296 * sys_execve() executes a new program.
297 */
298asmlinkage int sys_execve(const char __user *ufilename,
299 const char __user *const __user *uargv,
300 const char __user *const __user *uenvp,
301 unsigned long r7, struct pt_regs __regs)
302{
303 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
304 int error;
305 char *filename;
306
307 filename = getname(ufilename);
308 error = PTR_ERR(filename);
309 if (IS_ERR(filename))
310 goto out;
311
312 error = do_execve(filename, uargv, uenvp, regs);
313 putname(filename);
314out:
315 return error;
316}
317
318unsigned long get_wchan(struct task_struct *p)
319{
320 unsigned long pc;
321
322 if (!p || p == current || p->state == TASK_RUNNING)
323 return 0;
324
325 /*
326 * The same comment as on the Alpha applies here, too ...
327 */
328 pc = thread_saved_pc(p);
329
330#ifdef CONFIG_FRAME_POINTER
331 if (in_sched_functions(pc)) {
332 unsigned long schedule_frame = (unsigned long)p->thread.sp;
333 return ((unsigned long *)schedule_frame)[21];
334 }
335#endif
336
337 return pc;
338}