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v6.2
  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * OpenRISC process.c
  4 *
  5 * Linux architectural port borrowing liberally from similar works of
  6 * others.  All original copyrights apply as per the original source
  7 * declaration.
  8 *
  9 * Modifications for the OpenRISC architecture:
 10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
 11 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
 12 *
 13 * This file handles the architecture-dependent parts of process handling...
 14 */
 15
 16#define __KERNEL_SYSCALLS__
 
 
 17#include <linux/errno.h>
 18#include <linux/sched.h>
 19#include <linux/sched/debug.h>
 20#include <linux/sched/task.h>
 21#include <linux/sched/task_stack.h>
 22#include <linux/kernel.h>
 23#include <linux/export.h>
 24#include <linux/mm.h>
 25#include <linux/stddef.h>
 26#include <linux/unistd.h>
 27#include <linux/ptrace.h>
 28#include <linux/slab.h>
 29#include <linux/elfcore.h>
 30#include <linux/interrupt.h>
 31#include <linux/delay.h>
 32#include <linux/init_task.h>
 33#include <linux/mqueue.h>
 34#include <linux/fs.h>
 35#include <linux/reboot.h>
 36
 37#include <linux/uaccess.h>
 
 38#include <asm/io.h>
 39#include <asm/processor.h>
 40#include <asm/spr_defs.h>
 41
 42#include <linux/smp.h>
 43
 44/*
 45 * Pointer to Current thread info structure.
 46 *
 47 * Used at user space -> kernel transitions.
 48 */
 49struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, };
 50
 51void machine_restart(char *cmd)
 52{
 53	do_kernel_restart(cmd);
 54
 55	__asm__("l.nop 13");
 56
 57	/* Give a grace period for failure to restart of 1s */
 58	mdelay(1000);
 59
 60	/* Whoops - the platform was unable to reboot. Tell the user! */
 61	pr_emerg("Reboot failed -- System halted\n");
 62	while (1);
 63}
 64
 65/*
 66 * This is used if pm_power_off has not been set by a power management
 67 * driver, in this case we can assume we are on a simulator.  On
 68 * OpenRISC simulators l.nop 1 will trigger the simulator exit.
 69 */
 70static void default_power_off(void)
 71{
 
 72	__asm__("l.nop 1");
 73}
 74
 75/*
 76 * Similar to machine_power_off, but don't shut off power.  Add code
 77 * here to freeze the system for e.g. post-mortem debug purpose when
 78 * possible.  This halt has nothing to do with the idle halt.
 79 */
 80void machine_halt(void)
 81{
 82	printk(KERN_INFO "*** MACHINE HALT ***\n");
 83	__asm__("l.nop 1");
 84}
 85
 86/* If or when software power-off is implemented, add code here.  */
 87void machine_power_off(void)
 88{
 89	printk(KERN_INFO "*** MACHINE POWER OFF ***\n");
 90	if (pm_power_off != NULL)
 91		pm_power_off();
 92	else
 93		default_power_off();
 94}
 95
 96/*
 97 * Send the doze signal to the cpu if available.
 98 * Make sure, that all interrupts are enabled
 99 */
100void arch_cpu_idle(void)
101{
102	raw_local_irq_enable();
103	if (mfspr(SPR_UPR) & SPR_UPR_PMP)
104		mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME);
105}
106
107void (*pm_power_off)(void) = NULL;
108EXPORT_SYMBOL(pm_power_off);
109
110/*
111 * When a process does an "exec", machine state like FPU and debug
112 * registers need to be reset.  This is a hook function for that.
113 * Currently we don't have any such state to reset, so this is empty.
114 */
115void flush_thread(void)
116{
117}
118
119void show_regs(struct pt_regs *regs)
120{
121	extern void show_registers(struct pt_regs *regs);
122
123	show_regs_print_info(KERN_DEFAULT);
124	/* __PHX__ cleanup this mess */
125	show_registers(regs);
126}
127
 
 
 
 
128/*
129 * Copy the thread-specific (arch specific) info from the current
130 * process to the new one p
131 */
132extern asmlinkage void ret_from_fork(void);
133
134/*
135 * copy_thread
136 * @clone_flags: flags
137 * @usp: user stack pointer or fn for kernel thread
138 * @arg: arg to fn for kernel thread; always NULL for userspace thread
139 * @p: the newly created task
140 * @tls: the Thread Local Storage pointer for the new process
141 *
142 * At the top of a newly initialized kernel stack are two stacked pt_reg
143 * structures.  The first (topmost) is the userspace context of the thread.
144 * The second is the kernelspace context of the thread.
145 *
146 * A kernel thread will not be returning to userspace, so the topmost pt_regs
147 * struct can be uninitialized; it _does_ need to exist, though, because
148 * a kernel thread can become a userspace thread by doing a kernel_execve, in
149 * which case the topmost context will be initialized and used for 'returning'
150 * to userspace.
151 *
152 * The second pt_reg struct needs to be initialized to 'return' to
153 * ret_from_fork.  A kernel thread will need to set r20 to the address of
154 * a function to call into (with arg in r22); userspace threads need to set
155 * r20 to NULL in which case ret_from_fork will just continue a return to
156 * userspace.
157 *
158 * A kernel thread 'fn' may return; this is effectively what happens when
159 * kernel_execve is called.  In that case, the userspace pt_regs must have
160 * been initialized (which kernel_execve takes care of, see start_thread
161 * below); ret_from_fork will then continue its execution causing the
162 * 'kernel thread' to return to userspace as a userspace thread.
163 */
164
165int
166copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 
167{
168	unsigned long clone_flags = args->flags;
169	unsigned long usp = args->stack;
170	unsigned long tls = args->tls;
171	struct pt_regs *userregs;
172	struct pt_regs *kregs;
173	unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
174	unsigned long top_of_kernel_stack;
175
176	top_of_kernel_stack = sp;
177
178	/* Locate userspace context on stack... */
179	sp -= STACK_FRAME_OVERHEAD;	/* redzone */
180	sp -= sizeof(struct pt_regs);
181	userregs = (struct pt_regs *) sp;
182
183	/* ...and kernel context */
184	sp -= STACK_FRAME_OVERHEAD;	/* redzone */
185	sp -= sizeof(struct pt_regs);
186	kregs = (struct pt_regs *)sp;
187
188	if (unlikely(args->fn)) {
189		memset(kregs, 0, sizeof(struct pt_regs));
190		kregs->gpr[20] = (unsigned long)args->fn;
191		kregs->gpr[22] = (unsigned long)args->fn_arg;
192	} else {
193		*userregs = *current_pt_regs();
194
195		if (usp)
196			userregs->sp = usp;
197
198		/*
199		 * For CLONE_SETTLS set "tp" (r10) to the TLS pointer.
 
 
 
 
 
 
200		 */
201		if (clone_flags & CLONE_SETTLS)
202			userregs->gpr[10] = tls;
203
204		userregs->gpr[11] = 0;	/* Result from fork() */
205
206		kregs->gpr[20] = 0;	/* Userspace thread */
207	}
208
209	/*
210	 * _switch wants the kernel stack page in pt_regs->sp so that it
211	 * can restore it to thread_info->ksp... see _switch for details.
212	 */
213	kregs->sp = top_of_kernel_stack;
214	kregs->gpr[9] = (unsigned long)ret_from_fork;
215
216	task_thread_info(p)->ksp = (unsigned long)kregs;
217
218	return 0;
219}
220
221/*
222 * Set up a thread for executing a new program
223 */
224void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
225{
226	unsigned long sr = mfspr(SPR_SR) & ~SPR_SR_SM;
227
228	memset(regs, 0, sizeof(struct pt_regs));
229
230	regs->pc = pc;
231	regs->sr = sr;
232	regs->sp = sp;
233}
234
 
 
 
 
 
 
 
235extern struct thread_info *_switch(struct thread_info *old_ti,
236				   struct thread_info *new_ti);
237extern int lwa_flag;
238
239struct task_struct *__switch_to(struct task_struct *old,
240				struct task_struct *new)
241{
242	struct task_struct *last;
243	struct thread_info *new_ti, *old_ti;
244	unsigned long flags;
245
246	local_irq_save(flags);
247
248	/* current_set is an array of saved current pointers
249	 * (one for each cpu). we need them at user->kernel transition,
250	 * while we save them at kernel->user transition
251	 */
252	new_ti = new->stack;
253	old_ti = old->stack;
254
255	lwa_flag = 0;
256
257	current_thread_info_set[smp_processor_id()] = new_ti;
258	last = (_switch(old_ti, new_ti))->task;
259
260	local_irq_restore(flags);
261
262	return last;
263}
264
265/*
266 * Write out registers in core dump format, as defined by the
267 * struct user_regs_struct
268 */
269void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs)
270{
271	dest[0] = 0; /* r0 */
272	memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long));
273	dest[32] = regs->pc;
274	dest[33] = regs->sr;
275	dest[34] = 0;
276	dest[35] = 0;
277}
278
279unsigned long __get_wchan(struct task_struct *p)
280{
281	/* TODO */
282
283	return 0;
284}
v5.4
  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * OpenRISC process.c
  4 *
  5 * Linux architectural port borrowing liberally from similar works of
  6 * others.  All original copyrights apply as per the original source
  7 * declaration.
  8 *
  9 * Modifications for the OpenRISC architecture:
 10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
 11 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
 12 *
 13 * This file handles the architecture-dependent parts of process handling...
 14 */
 15
 16#define __KERNEL_SYSCALLS__
 17#include <stdarg.h>
 18
 19#include <linux/errno.h>
 20#include <linux/sched.h>
 21#include <linux/sched/debug.h>
 22#include <linux/sched/task.h>
 23#include <linux/sched/task_stack.h>
 24#include <linux/kernel.h>
 25#include <linux/export.h>
 26#include <linux/mm.h>
 27#include <linux/stddef.h>
 28#include <linux/unistd.h>
 29#include <linux/ptrace.h>
 30#include <linux/slab.h>
 31#include <linux/elfcore.h>
 32#include <linux/interrupt.h>
 33#include <linux/delay.h>
 34#include <linux/init_task.h>
 35#include <linux/mqueue.h>
 36#include <linux/fs.h>
 
 37
 38#include <linux/uaccess.h>
 39#include <asm/pgtable.h>
 40#include <asm/io.h>
 41#include <asm/processor.h>
 42#include <asm/spr_defs.h>
 43
 44#include <linux/smp.h>
 45
 46/*
 47 * Pointer to Current thread info structure.
 48 *
 49 * Used at user space -> kernel transitions.
 50 */
 51struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, };
 52
 53void machine_restart(void)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 54{
 55	printk(KERN_INFO "*** MACHINE RESTART ***\n");
 56	__asm__("l.nop 1");
 57}
 58
 59/*
 60 * Similar to machine_power_off, but don't shut off power.  Add code
 61 * here to freeze the system for e.g. post-mortem debug purpose when
 62 * possible.  This halt has nothing to do with the idle halt.
 63 */
 64void machine_halt(void)
 65{
 66	printk(KERN_INFO "*** MACHINE HALT ***\n");
 67	__asm__("l.nop 1");
 68}
 69
 70/* If or when software power-off is implemented, add code here.  */
 71void machine_power_off(void)
 72{
 73	printk(KERN_INFO "*** MACHINE POWER OFF ***\n");
 74	__asm__("l.nop 1");
 
 
 
 75}
 76
 77/*
 78 * Send the doze signal to the cpu if available.
 79 * Make sure, that all interrupts are enabled
 80 */
 81void arch_cpu_idle(void)
 82{
 83	local_irq_enable();
 84	if (mfspr(SPR_UPR) & SPR_UPR_PMP)
 85		mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME);
 86}
 87
 88void (*pm_power_off) (void) = machine_power_off;
 89EXPORT_SYMBOL(pm_power_off);
 90
 91/*
 92 * When a process does an "exec", machine state like FPU and debug
 93 * registers need to be reset.  This is a hook function for that.
 94 * Currently we don't have any such state to reset, so this is empty.
 95 */
 96void flush_thread(void)
 97{
 98}
 99
100void show_regs(struct pt_regs *regs)
101{
102	extern void show_registers(struct pt_regs *regs);
103
104	show_regs_print_info(KERN_DEFAULT);
105	/* __PHX__ cleanup this mess */
106	show_registers(regs);
107}
108
109void release_thread(struct task_struct *dead_task)
110{
111}
112
113/*
114 * Copy the thread-specific (arch specific) info from the current
115 * process to the new one p
116 */
117extern asmlinkage void ret_from_fork(void);
118
119/*
120 * copy_thread
121 * @clone_flags: flags
122 * @usp: user stack pointer or fn for kernel thread
123 * @arg: arg to fn for kernel thread; always NULL for userspace thread
124 * @p: the newly created task
125 * @regs: CPU context to copy for userspace thread; always NULL for kthread
126 *
127 * At the top of a newly initialized kernel stack are two stacked pt_reg
128 * structures.  The first (topmost) is the userspace context of the thread.
129 * The second is the kernelspace context of the thread.
130 *
131 * A kernel thread will not be returning to userspace, so the topmost pt_regs
132 * struct can be uninitialized; it _does_ need to exist, though, because
133 * a kernel thread can become a userspace thread by doing a kernel_execve, in
134 * which case the topmost context will be initialized and used for 'returning'
135 * to userspace.
136 *
137 * The second pt_reg struct needs to be initialized to 'return' to
138 * ret_from_fork.  A kernel thread will need to set r20 to the address of
139 * a function to call into (with arg in r22); userspace threads need to set
140 * r20 to NULL in which case ret_from_fork will just continue a return to
141 * userspace.
142 *
143 * A kernel thread 'fn' may return; this is effectively what happens when
144 * kernel_execve is called.  In that case, the userspace pt_regs must have
145 * been initialized (which kernel_execve takes care of, see start_thread
146 * below); ret_from_fork will then continue its execution causing the
147 * 'kernel thread' to return to userspace as a userspace thread.
148 */
149
150int
151copy_thread(unsigned long clone_flags, unsigned long usp,
152	    unsigned long arg, struct task_struct *p)
153{
 
 
 
154	struct pt_regs *userregs;
155	struct pt_regs *kregs;
156	unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
157	unsigned long top_of_kernel_stack;
158
159	top_of_kernel_stack = sp;
160
161	/* Locate userspace context on stack... */
162	sp -= STACK_FRAME_OVERHEAD;	/* redzone */
163	sp -= sizeof(struct pt_regs);
164	userregs = (struct pt_regs *) sp;
165
166	/* ...and kernel context */
167	sp -= STACK_FRAME_OVERHEAD;	/* redzone */
168	sp -= sizeof(struct pt_regs);
169	kregs = (struct pt_regs *)sp;
170
171	if (unlikely(p->flags & PF_KTHREAD)) {
172		memset(kregs, 0, sizeof(struct pt_regs));
173		kregs->gpr[20] = usp; /* fn, kernel thread */
174		kregs->gpr[22] = arg;
175	} else {
176		*userregs = *current_pt_regs();
177
178		if (usp)
179			userregs->sp = usp;
180
181		/*
182		 * For CLONE_SETTLS set "tp" (r10) to the TLS pointer passed to sys_clone.
183		 *
184		 * The kernel entry is:
185		 *	int clone (long flags, void *child_stack, int *parent_tid,
186		 *		int *child_tid, struct void *tls)
187		 *
188		 * This makes the source r7 in the kernel registers.
189		 */
190		if (clone_flags & CLONE_SETTLS)
191			userregs->gpr[10] = userregs->gpr[7];
192
193		userregs->gpr[11] = 0;	/* Result from fork() */
194
195		kregs->gpr[20] = 0;	/* Userspace thread */
196	}
197
198	/*
199	 * _switch wants the kernel stack page in pt_regs->sp so that it
200	 * can restore it to thread_info->ksp... see _switch for details.
201	 */
202	kregs->sp = top_of_kernel_stack;
203	kregs->gpr[9] = (unsigned long)ret_from_fork;
204
205	task_thread_info(p)->ksp = (unsigned long)kregs;
206
207	return 0;
208}
209
210/*
211 * Set up a thread for executing a new program
212 */
213void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
214{
215	unsigned long sr = mfspr(SPR_SR) & ~SPR_SR_SM;
216
217	memset(regs, 0, sizeof(struct pt_regs));
218
219	regs->pc = pc;
220	regs->sr = sr;
221	regs->sp = sp;
222}
223
224/* Fill in the fpu structure for a core dump.  */
225int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpu)
226{
227	/* TODO */
228	return 0;
229}
230
231extern struct thread_info *_switch(struct thread_info *old_ti,
232				   struct thread_info *new_ti);
233extern int lwa_flag;
234
235struct task_struct *__switch_to(struct task_struct *old,
236				struct task_struct *new)
237{
238	struct task_struct *last;
239	struct thread_info *new_ti, *old_ti;
240	unsigned long flags;
241
242	local_irq_save(flags);
243
244	/* current_set is an array of saved current pointers
245	 * (one for each cpu). we need them at user->kernel transition,
246	 * while we save them at kernel->user transition
247	 */
248	new_ti = new->stack;
249	old_ti = old->stack;
250
251	lwa_flag = 0;
252
253	current_thread_info_set[smp_processor_id()] = new_ti;
254	last = (_switch(old_ti, new_ti))->task;
255
256	local_irq_restore(flags);
257
258	return last;
259}
260
261/*
262 * Write out registers in core dump format, as defined by the
263 * struct user_regs_struct
264 */
265void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs)
266{
267	dest[0] = 0; /* r0 */
268	memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long));
269	dest[32] = regs->pc;
270	dest[33] = regs->sr;
271	dest[34] = 0;
272	dest[35] = 0;
273}
274
275unsigned long get_wchan(struct task_struct *p)
276{
277	/* TODO */
278
279	return 0;
280}