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273 lines
7.1 KiB
273 lines
7.1 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* OpenRISC process.c |
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* |
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* Linux architectural port borrowing liberally from similar works of |
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* others. All original copyrights apply as per the original source |
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* declaration. |
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* |
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* Modifications for the OpenRISC architecture: |
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* Copyright (C) 2003 Matjaz Breskvar <[email protected]> |
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* Copyright (C) 2010-2011 Jonas Bonn <[email protected]> |
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* |
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* This file handles the architecture-dependent parts of process handling... |
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*/ |
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#define __KERNEL_SYSCALLS__ |
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#include <stdarg.h> |
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#include <linux/errno.h> |
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#include <linux/sched.h> |
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#include <linux/sched/debug.h> |
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#include <linux/sched/task.h> |
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#include <linux/sched/task_stack.h> |
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#include <linux/kernel.h> |
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#include <linux/export.h> |
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#include <linux/mm.h> |
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#include <linux/stddef.h> |
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#include <linux/unistd.h> |
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#include <linux/ptrace.h> |
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#include <linux/slab.h> |
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#include <linux/elfcore.h> |
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#include <linux/interrupt.h> |
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#include <linux/delay.h> |
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#include <linux/init_task.h> |
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#include <linux/mqueue.h> |
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#include <linux/fs.h> |
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#include <linux/reboot.h> |
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#include <linux/uaccess.h> |
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#include <asm/io.h> |
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#include <asm/processor.h> |
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#include <asm/spr_defs.h> |
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#include <linux/smp.h> |
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/* |
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* Pointer to Current thread info structure. |
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* |
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* Used at user space -> kernel transitions. |
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*/ |
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struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, }; |
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void machine_restart(char *cmd) |
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{ |
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do_kernel_restart(cmd); |
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/* Give a grace period for failure to restart of 1s */ |
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mdelay(1000); |
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/* Whoops - the platform was unable to reboot. Tell the user! */ |
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pr_emerg("Reboot failed -- System halted\n"); |
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while (1); |
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} |
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/* |
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* Similar to machine_power_off, but don't shut off power. Add code |
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* here to freeze the system for e.g. post-mortem debug purpose when |
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* possible. This halt has nothing to do with the idle halt. |
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*/ |
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void machine_halt(void) |
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{ |
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printk(KERN_INFO "*** MACHINE HALT ***\n"); |
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__asm__("l.nop 1"); |
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} |
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/* If or when software power-off is implemented, add code here. */ |
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void machine_power_off(void) |
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{ |
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printk(KERN_INFO "*** MACHINE POWER OFF ***\n"); |
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__asm__("l.nop 1"); |
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} |
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/* |
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* Send the doze signal to the cpu if available. |
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* Make sure, that all interrupts are enabled |
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*/ |
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void arch_cpu_idle(void) |
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{ |
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raw_local_irq_enable(); |
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if (mfspr(SPR_UPR) & SPR_UPR_PMP) |
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mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME); |
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} |
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void (*pm_power_off) (void) = machine_power_off; |
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EXPORT_SYMBOL(pm_power_off); |
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/* |
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* When a process does an "exec", machine state like FPU and debug |
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* registers need to be reset. This is a hook function for that. |
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* Currently we don't have any such state to reset, so this is empty. |
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*/ |
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void flush_thread(void) |
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{ |
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} |
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void show_regs(struct pt_regs *regs) |
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{ |
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extern void show_registers(struct pt_regs *regs); |
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show_regs_print_info(KERN_DEFAULT); |
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/* __PHX__ cleanup this mess */ |
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show_registers(regs); |
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} |
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void release_thread(struct task_struct *dead_task) |
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{ |
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} |
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/* |
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* Copy the thread-specific (arch specific) info from the current |
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* process to the new one p |
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*/ |
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extern asmlinkage void ret_from_fork(void); |
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/* |
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* copy_thread |
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* @clone_flags: flags |
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* @usp: user stack pointer or fn for kernel thread |
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* @arg: arg to fn for kernel thread; always NULL for userspace thread |
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* @p: the newly created task |
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* @tls: the Thread Local Storage pointer for the new process |
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* |
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* At the top of a newly initialized kernel stack are two stacked pt_reg |
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* structures. The first (topmost) is the userspace context of the thread. |
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* The second is the kernelspace context of the thread. |
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* |
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* A kernel thread will not be returning to userspace, so the topmost pt_regs |
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* struct can be uninitialized; it _does_ need to exist, though, because |
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* a kernel thread can become a userspace thread by doing a kernel_execve, in |
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* which case the topmost context will be initialized and used for 'returning' |
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* to userspace. |
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* |
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* The second pt_reg struct needs to be initialized to 'return' to |
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* ret_from_fork. A kernel thread will need to set r20 to the address of |
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* a function to call into (with arg in r22); userspace threads need to set |
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* r20 to NULL in which case ret_from_fork will just continue a return to |
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* userspace. |
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* |
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* A kernel thread 'fn' may return; this is effectively what happens when |
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* kernel_execve is called. In that case, the userspace pt_regs must have |
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* been initialized (which kernel_execve takes care of, see start_thread |
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* below); ret_from_fork will then continue its execution causing the |
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* 'kernel thread' to return to userspace as a userspace thread. |
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*/ |
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int |
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copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg, |
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struct task_struct *p, unsigned long tls) |
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{ |
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struct pt_regs *userregs; |
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struct pt_regs *kregs; |
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unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE; |
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unsigned long top_of_kernel_stack; |
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top_of_kernel_stack = sp; |
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/* Locate userspace context on stack... */ |
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sp -= STACK_FRAME_OVERHEAD; /* redzone */ |
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sp -= sizeof(struct pt_regs); |
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userregs = (struct pt_regs *) sp; |
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/* ...and kernel context */ |
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sp -= STACK_FRAME_OVERHEAD; /* redzone */ |
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sp -= sizeof(struct pt_regs); |
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kregs = (struct pt_regs *)sp; |
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if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) { |
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memset(kregs, 0, sizeof(struct pt_regs)); |
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kregs->gpr[20] = usp; /* fn, kernel thread */ |
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kregs->gpr[22] = arg; |
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} else { |
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*userregs = *current_pt_regs(); |
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if (usp) |
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userregs->sp = usp; |
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/* |
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* For CLONE_SETTLS set "tp" (r10) to the TLS pointer. |
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*/ |
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if (clone_flags & CLONE_SETTLS) |
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userregs->gpr[10] = tls; |
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userregs->gpr[11] = 0; /* Result from fork() */ |
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kregs->gpr[20] = 0; /* Userspace thread */ |
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} |
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/* |
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* _switch wants the kernel stack page in pt_regs->sp so that it |
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* can restore it to thread_info->ksp... see _switch for details. |
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*/ |
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kregs->sp = top_of_kernel_stack; |
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kregs->gpr[9] = (unsigned long)ret_from_fork; |
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task_thread_info(p)->ksp = (unsigned long)kregs; |
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return 0; |
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} |
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/* |
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* Set up a thread for executing a new program |
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*/ |
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void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) |
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{ |
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unsigned long sr = mfspr(SPR_SR) & ~SPR_SR_SM; |
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memset(regs, 0, sizeof(struct pt_regs)); |
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regs->pc = pc; |
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regs->sr = sr; |
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regs->sp = sp; |
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} |
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extern struct thread_info *_switch(struct thread_info *old_ti, |
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struct thread_info *new_ti); |
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extern int lwa_flag; |
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struct task_struct *__switch_to(struct task_struct *old, |
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struct task_struct *new) |
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{ |
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struct task_struct *last; |
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struct thread_info *new_ti, *old_ti; |
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unsigned long flags; |
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local_irq_save(flags); |
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/* current_set is an array of saved current pointers |
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* (one for each cpu). we need them at user->kernel transition, |
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* while we save them at kernel->user transition |
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*/ |
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new_ti = new->stack; |
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old_ti = old->stack; |
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lwa_flag = 0; |
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current_thread_info_set[smp_processor_id()] = new_ti; |
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last = (_switch(old_ti, new_ti))->task; |
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local_irq_restore(flags); |
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return last; |
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} |
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/* |
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* Write out registers in core dump format, as defined by the |
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* struct user_regs_struct |
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*/ |
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void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs) |
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{ |
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dest[0] = 0; /* r0 */ |
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memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long)); |
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dest[32] = regs->pc; |
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dest[33] = regs->sr; |
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dest[34] = 0; |
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dest[35] = 0; |
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} |
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unsigned long get_wchan(struct task_struct *p) |
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{ |
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/* TODO */ |
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return 0; |
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}
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