1 // SPDX-License-Identifier: GPL-2.0-or-later
5 * Linux architectural port borrowing liberally from similar works of
6 * others. All original copyrights apply as per the original source
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>
13 * This file handles the architecture-dependent parts of process handling...
16 #define __KERNEL_SYSCALLS__
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>
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>
38 #include <linux/uaccess.h>
40 #include <asm/processor.h>
41 #include <asm/spr_defs.h>
43 #include <linux/smp.h>
46 * Pointer to Current thread info structure.
48 * Used at user space -> kernel transitions.
50 struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, };
52 void machine_restart(void)
54 printk(KERN_INFO "*** MACHINE RESTART ***\n");
59 * Similar to machine_power_off, but don't shut off power. Add code
60 * here to freeze the system for e.g. post-mortem debug purpose when
61 * possible. This halt has nothing to do with the idle halt.
63 void machine_halt(void)
65 printk(KERN_INFO "*** MACHINE HALT ***\n");
69 /* If or when software power-off is implemented, add code here. */
70 void machine_power_off(void)
72 printk(KERN_INFO "*** MACHINE POWER OFF ***\n");
77 * Send the doze signal to the cpu if available.
78 * Make sure, that all interrupts are enabled
80 void arch_cpu_idle(void)
82 raw_local_irq_enable();
83 if (mfspr(SPR_UPR) & SPR_UPR_PMP)
84 mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME);
87 void (*pm_power_off) (void) = machine_power_off;
88 EXPORT_SYMBOL(pm_power_off);
91 * When a process does an "exec", machine state like FPU and debug
92 * registers need to be reset. This is a hook function for that.
93 * Currently we don't have any such state to reset, so this is empty.
95 void flush_thread(void)
99 void show_regs(struct pt_regs *regs)
101 extern void show_registers(struct pt_regs *regs);
103 show_regs_print_info(KERN_DEFAULT);
104 /* __PHX__ cleanup this mess */
105 show_registers(regs);
108 void release_thread(struct task_struct *dead_task)
113 * Copy the thread-specific (arch specific) info from the current
114 * process to the new one p
116 extern asmlinkage void ret_from_fork(void);
120 * @clone_flags: flags
121 * @usp: user stack pointer or fn for kernel thread
122 * @arg: arg to fn for kernel thread; always NULL for userspace thread
123 * @p: the newly created task
124 * @tls: the Thread Local Storage pointer for the new process
126 * At the top of a newly initialized kernel stack are two stacked pt_reg
127 * structures. The first (topmost) is the userspace context of the thread.
128 * The second is the kernelspace context of the thread.
130 * A kernel thread will not be returning to userspace, so the topmost pt_regs
131 * struct can be uninitialized; it _does_ need to exist, though, because
132 * a kernel thread can become a userspace thread by doing a kernel_execve, in
133 * which case the topmost context will be initialized and used for 'returning'
136 * The second pt_reg struct needs to be initialized to 'return' to
137 * ret_from_fork. A kernel thread will need to set r20 to the address of
138 * a function to call into (with arg in r22); userspace threads need to set
139 * r20 to NULL in which case ret_from_fork will just continue a return to
142 * A kernel thread 'fn' may return; this is effectively what happens when
143 * kernel_execve is called. In that case, the userspace pt_regs must have
144 * been initialized (which kernel_execve takes care of, see start_thread
145 * below); ret_from_fork will then continue its execution causing the
146 * 'kernel thread' to return to userspace as a userspace thread.
150 copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
151 struct task_struct *p, unsigned long tls)
153 struct pt_regs *userregs;
154 struct pt_regs *kregs;
155 unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
156 unsigned long top_of_kernel_stack;
158 top_of_kernel_stack = sp;
160 /* Locate userspace context on stack... */
161 sp -= STACK_FRAME_OVERHEAD; /* redzone */
162 sp -= sizeof(struct pt_regs);
163 userregs = (struct pt_regs *) sp;
165 /* ...and kernel context */
166 sp -= STACK_FRAME_OVERHEAD; /* redzone */
167 sp -= sizeof(struct pt_regs);
168 kregs = (struct pt_regs *)sp;
170 if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
171 memset(kregs, 0, sizeof(struct pt_regs));
172 kregs->gpr[20] = usp; /* fn, kernel thread */
173 kregs->gpr[22] = arg;
175 *userregs = *current_pt_regs();
181 * For CLONE_SETTLS set "tp" (r10) to the TLS pointer.
183 if (clone_flags & CLONE_SETTLS)
184 userregs->gpr[10] = tls;
186 userregs->gpr[11] = 0; /* Result from fork() */
188 kregs->gpr[20] = 0; /* Userspace thread */
192 * _switch wants the kernel stack page in pt_regs->sp so that it
193 * can restore it to thread_info->ksp... see _switch for details.
195 kregs->sp = top_of_kernel_stack;
196 kregs->gpr[9] = (unsigned long)ret_from_fork;
198 task_thread_info(p)->ksp = (unsigned long)kregs;
204 * Set up a thread for executing a new program
206 void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
208 unsigned long sr = mfspr(SPR_SR) & ~SPR_SR_SM;
210 memset(regs, 0, sizeof(struct pt_regs));
217 extern struct thread_info *_switch(struct thread_info *old_ti,
218 struct thread_info *new_ti);
221 struct task_struct *__switch_to(struct task_struct *old,
222 struct task_struct *new)
224 struct task_struct *last;
225 struct thread_info *new_ti, *old_ti;
228 local_irq_save(flags);
230 /* current_set is an array of saved current pointers
231 * (one for each cpu). we need them at user->kernel transition,
232 * while we save them at kernel->user transition
239 current_thread_info_set[smp_processor_id()] = new_ti;
240 last = (_switch(old_ti, new_ti))->task;
242 local_irq_restore(flags);
248 * Write out registers in core dump format, as defined by the
249 * struct user_regs_struct
251 void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs)
253 dest[0] = 0; /* r0 */
254 memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long));
261 unsigned long get_wchan(struct task_struct *p)