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git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - arch/openrisc/kernel/process.c
4 * Linux architectural port borrowing liberally from similar works of
5 * others. All original copyrights apply as per the original source
8 * Modifications for the OpenRISC architecture:
9 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
10 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
17 * This file handles the architecture-dependent parts of process handling...
20 #define __KERNEL_SYSCALLS__
23 #include <linux/errno.h>
24 #include <linux/sched.h>
25 #include <linux/sched/debug.h>
26 #include <linux/sched/task.h>
27 #include <linux/kernel.h>
28 #include <linux/module.h>
30 #include <linux/stddef.h>
31 #include <linux/unistd.h>
32 #include <linux/ptrace.h>
33 #include <linux/slab.h>
34 #include <linux/elfcore.h>
35 #include <linux/interrupt.h>
36 #include <linux/delay.h>
37 #include <linux/init_task.h>
38 #include <linux/mqueue.h>
41 #include <linux/uaccess.h>
42 #include <asm/pgtable.h>
44 #include <asm/processor.h>
45 #include <asm/spr_defs.h>
47 #include <linux/smp.h>
50 * Pointer to Current thread info structure.
52 * Used at user space -> kernel transitions.
54 struct thread_info
*current_thread_info_set
[NR_CPUS
] = { &init_thread_info
, };
56 void machine_restart(void)
58 printk(KERN_INFO
"*** MACHINE RESTART ***\n");
63 * Similar to machine_power_off, but don't shut off power. Add code
64 * here to freeze the system for e.g. post-mortem debug purpose when
65 * possible. This halt has nothing to do with the idle halt.
67 void machine_halt(void)
69 printk(KERN_INFO
"*** MACHINE HALT ***\n");
73 /* If or when software power-off is implemented, add code here. */
74 void machine_power_off(void)
76 printk(KERN_INFO
"*** MACHINE POWER OFF ***\n");
81 * Send the doze signal to the cpu if available.
82 * Make sure, that all interrupts are enabled
84 void arch_cpu_idle(void)
87 if (mfspr(SPR_UPR
) & SPR_UPR_PMP
)
88 mtspr(SPR_PMR
, mfspr(SPR_PMR
) | SPR_PMR_DME
);
91 void (*pm_power_off
) (void) = machine_power_off
;
94 * When a process does an "exec", machine state like FPU and debug
95 * registers need to be reset. This is a hook function for that.
96 * Currently we don't have any such state to reset, so this is empty.
98 void flush_thread(void)
102 void show_regs(struct pt_regs
*regs
)
104 extern void show_registers(struct pt_regs
*regs
);
106 show_regs_print_info(KERN_DEFAULT
);
107 /* __PHX__ cleanup this mess */
108 show_registers(regs
);
111 unsigned long thread_saved_pc(struct task_struct
*t
)
113 return (unsigned long)user_regs(t
->stack
)->pc
;
116 void release_thread(struct task_struct
*dead_task
)
121 * Copy the thread-specific (arch specific) info from the current
122 * process to the new one p
124 extern asmlinkage
void ret_from_fork(void);
128 * @clone_flags: flags
129 * @usp: user stack pointer or fn for kernel thread
130 * @arg: arg to fn for kernel thread; always NULL for userspace thread
131 * @p: the newly created task
132 * @regs: CPU context to copy for userspace thread; always NULL for kthread
134 * At the top of a newly initialized kernel stack are two stacked pt_reg
135 * structures. The first (topmost) is the userspace context of the thread.
136 * The second is the kernelspace context of the thread.
138 * A kernel thread will not be returning to userspace, so the topmost pt_regs
139 * struct can be uninitialized; it _does_ need to exist, though, because
140 * a kernel thread can become a userspace thread by doing a kernel_execve, in
141 * which case the topmost context will be initialized and used for 'returning'
144 * The second pt_reg struct needs to be initialized to 'return' to
145 * ret_from_fork. A kernel thread will need to set r20 to the address of
146 * a function to call into (with arg in r22); userspace threads need to set
147 * r20 to NULL in which case ret_from_fork will just continue a return to
150 * A kernel thread 'fn' may return; this is effectively what happens when
151 * kernel_execve is called. In that case, the userspace pt_regs must have
152 * been initialized (which kernel_execve takes care of, see start_thread
153 * below); ret_from_fork will then continue its execution causing the
154 * 'kernel thread' to return to userspace as a userspace thread.
158 copy_thread(unsigned long clone_flags
, unsigned long usp
,
159 unsigned long arg
, struct task_struct
*p
)
161 struct pt_regs
*userregs
;
162 struct pt_regs
*kregs
;
163 unsigned long sp
= (unsigned long)task_stack_page(p
) + THREAD_SIZE
;
164 unsigned long top_of_kernel_stack
;
166 top_of_kernel_stack
= sp
;
168 p
->set_child_tid
= p
->clear_child_tid
= NULL
;
170 /* Locate userspace context on stack... */
171 sp
-= STACK_FRAME_OVERHEAD
; /* redzone */
172 sp
-= sizeof(struct pt_regs
);
173 userregs
= (struct pt_regs
*) sp
;
175 /* ...and kernel context */
176 sp
-= STACK_FRAME_OVERHEAD
; /* redzone */
177 sp
-= sizeof(struct pt_regs
);
178 kregs
= (struct pt_regs
*)sp
;
180 if (unlikely(p
->flags
& PF_KTHREAD
)) {
181 memset(kregs
, 0, sizeof(struct pt_regs
));
182 kregs
->gpr
[20] = usp
; /* fn, kernel thread */
183 kregs
->gpr
[22] = arg
;
185 *userregs
= *current_pt_regs();
191 * For CLONE_SETTLS set "tp" (r10) to the TLS pointer passed to sys_clone.
193 * The kernel entry is:
194 * int clone (long flags, void *child_stack, int *parent_tid,
195 * int *child_tid, struct void *tls)
197 * This makes the source r7 in the kernel registers.
199 if (clone_flags
& CLONE_SETTLS
)
200 userregs
->gpr
[10] = userregs
->gpr
[7];
202 userregs
->gpr
[11] = 0; /* Result from fork() */
204 kregs
->gpr
[20] = 0; /* Userspace thread */
208 * _switch wants the kernel stack page in pt_regs->sp so that it
209 * can restore it to thread_info->ksp... see _switch for details.
211 kregs
->sp
= top_of_kernel_stack
;
212 kregs
->gpr
[9] = (unsigned long)ret_from_fork
;
214 task_thread_info(p
)->ksp
= (unsigned long)kregs
;
220 * Set up a thread for executing a new program
222 void start_thread(struct pt_regs
*regs
, unsigned long pc
, unsigned long sp
)
224 unsigned long sr
= mfspr(SPR_SR
) & ~SPR_SR_SM
;
226 memset(regs
, 0, sizeof(struct pt_regs
));
233 /* Fill in the fpu structure for a core dump. */
234 int dump_fpu(struct pt_regs
*regs
, elf_fpregset_t
* fpu
)
240 extern struct thread_info
*_switch(struct thread_info
*old_ti
,
241 struct thread_info
*new_ti
);
244 struct task_struct
*__switch_to(struct task_struct
*old
,
245 struct task_struct
*new)
247 struct task_struct
*last
;
248 struct thread_info
*new_ti
, *old_ti
;
251 local_irq_save(flags
);
253 /* current_set is an array of saved current pointers
254 * (one for each cpu). we need them at user->kernel transition,
255 * while we save them at kernel->user transition
262 current_thread_info_set
[smp_processor_id()] = new_ti
;
263 last
= (_switch(old_ti
, new_ti
))->task
;
265 local_irq_restore(flags
);
271 * Write out registers in core dump format, as defined by the
272 * struct user_regs_struct
274 void dump_elf_thread(elf_greg_t
*dest
, struct pt_regs
* regs
)
276 dest
[0] = 0; /* r0 */
277 memcpy(dest
+1, regs
->gpr
+1, 31*sizeof(unsigned long));
284 unsigned long get_wchan(struct task_struct
*p
)