1 files changed, 261 insertions, 0 deletions
diff --git a/arch/openrisc/kernel/process.c b/arch/openrisc/kernel/process.c
new file mode 100644
index 00000000000..386af258591
--- /dev/null
+++ b/arch/openrisc/kernel/process.c
@@ -0,0 +1,261 @@
+/*
+ * OpenRISC process.c
+ *
+ * Linux architectural port borrowing liberally from similar works of
+ * others.  All original copyrights apply as per the original source
+ * declaration.
+ *
+ * Modifications for the OpenRISC architecture:
+ * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
+ * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ *
+ * This file handles the architecture-dependent parts of process handling...
+ */
+
+#define __KERNEL_SYSCALLS__
+#include <stdarg.h>
+
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/stddef.h>
+#include <linux/unistd.h>
+#include <linux/ptrace.h>
+#include <linux/slab.h>
+#include <linux/elfcore.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/init_task.h>
+#include <linux/mqueue.h>
+#include <linux/fs.h>
+
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+#include <asm/spr_defs.h>
+
+#include <linux/smp.h>
+
+/*
+ * Pointer to Current thread info structure.
+ *
+ * Used at user space -> kernel transitions.
+ */
+struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, };
+
+void machine_restart(void)
+{
+	printk(KERN_INFO "*** MACHINE RESTART ***\n");
+	__asm__("l.nop 1");
+}
+
+/*
+ * Similar to machine_power_off, but don't shut off power.  Add code
+ * here to freeze the system for e.g. post-mortem debug purpose when
+ * possible.  This halt has nothing to do with the idle halt.
+ */
+void machine_halt(void)
+{
+	printk(KERN_INFO "*** MACHINE HALT ***\n");
+	__asm__("l.nop 1");
+}
+
+/* If or when software power-off is implemented, add code here.  */
+void machine_power_off(void)
+{
+	printk(KERN_INFO "*** MACHINE POWER OFF ***\n");
+	__asm__("l.nop 1");
+}
+
+void (*pm_power_off) (void) = machine_power_off;
+
+/*
+ * When a process does an "exec", machine state like FPU and debug
+ * registers need to be reset.  This is a hook function for that.
+ * Currently we don't have any such state to reset, so this is empty.
+ */
+void flush_thread(void)
+{
+}
+
+void show_regs(struct pt_regs *regs)
+{
+	extern void show_registers(struct pt_regs *regs);
+
+	show_regs_print_info(KERN_DEFAULT);
+	/* __PHX__ cleanup this mess */
+	show_registers(regs);
+}
+
+unsigned long thread_saved_pc(struct task_struct *t)
+{
+	return (unsigned long)user_regs(t->stack)->pc;
+}
+
+void release_thread(struct task_struct *dead_task)
+{
+}
+
+/*
+ * Copy the thread-specific (arch specific) info from the current
+ * process to the new one p
+ */
+extern asmlinkage void ret_from_fork(void);
+
+/*
+ * copy_thread
+ * @clone_flags: flags
+ * @usp: user stack pointer or fn for kernel thread
+ * @arg: arg to fn for kernel thread; always NULL for userspace thread
+ * @p: the newly created task
+ * @regs: CPU context to copy for userspace thread; always NULL for kthread
+ *
+ * At the top of a newly initialized kernel stack are two stacked pt_reg
+ * structures.  The first (topmost) is the userspace context of the thread.
+ * The second is the kernelspace context of the thread.
+ *
+ * A kernel thread will not be returning to userspace, so the topmost pt_regs
+ * struct can be uninitialized; it _does_ need to exist, though, because
+ * a kernel thread can become a userspace thread by doing a kernel_execve, in
+ * which case the topmost context will be initialized and used for 'returning'
+ * to userspace.
+ *
+ * The second pt_reg struct needs to be initialized to 'return' to
+ * ret_from_fork.  A kernel thread will need to set r20 to the address of
+ * a function to call into (with arg in r22); userspace threads need to set
+ * r20 to NULL in which case ret_from_fork will just continue a return to
+ * userspace.
+ *
+ * A kernel thread 'fn' may return; this is effectively what happens when
+ * kernel_execve is called.  In that case, the userspace pt_regs must have
+ * been initialized (which kernel_execve takes care of, see start_thread
+ * below); ret_from_fork will then continue its execution causing the
+ * 'kernel thread' to return to userspace as a userspace thread.
+ */
+
+int
+copy_thread(unsigned long clone_flags, unsigned long usp,
+	    unsigned long arg, struct task_struct *p)
+{
+	struct pt_regs *userregs;
+	struct pt_regs *kregs;
+	unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
+	unsigned long top_of_kernel_stack;
+
+	top_of_kernel_stack = sp;
+
+	p->set_child_tid = p->clear_child_tid = NULL;
+
+	/* Locate userspace context on stack... */
+	sp -= STACK_FRAME_OVERHEAD;	/* redzone */
+	sp -= sizeof(struct pt_regs);
+	userregs = (struct pt_regs *) sp;
+
+	/* ...and kernel context */
+	sp -= STACK_FRAME_OVERHEAD;	/* redzone */
+	sp -= sizeof(struct pt_regs);
+	kregs = (struct pt_regs *)sp;
+
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		memset(kregs, 0, sizeof(struct pt_regs));
+		kregs->gpr[20] = usp; /* fn, kernel thread */
+		kregs->gpr[22] = arg;
+	} else {
+		*userregs = *current_pt_regs();
+
+		if (usp)
+			userregs->sp = usp;
+		userregs->gpr[11] = 0;	/* Result from fork() */
+
+		kregs->gpr[20] = 0;	/* Userspace thread */
+	}
+
+	/*
+	 * _switch wants the kernel stack page in pt_regs->sp so that it
+	 * can restore it to thread_info->ksp... see _switch for details.
+	 */
+	kregs->sp = top_of_kernel_stack;
+	kregs->gpr[9] = (unsigned long)ret_from_fork;
+
+	task_thread_info(p)->ksp = (unsigned long)kregs;
+
+	return 0;
+}
+
+/*
+ * Set up a thread for executing a new program
+ */
+void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
+{
+	unsigned long sr = mfspr(SPR_SR) & ~SPR_SR_SM;
+
+	set_fs(USER_DS);
+	memset(regs, 0, sizeof(struct pt_regs));
+
+	regs->pc = pc;
+	regs->sr = sr;
+	regs->sp = sp;
+}
+
+/* Fill in the fpu structure for a core dump.  */
+int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpu)
+{
+	/* TODO */
+	return 0;
+}
+
+extern struct thread_info *_switch(struct thread_info *old_ti,
+				   struct thread_info *new_ti);
+
+struct task_struct *__switch_to(struct task_struct *old,
+				struct task_struct *new)
+{
+	struct task_struct *last;
+	struct thread_info *new_ti, *old_ti;
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	/* current_set is an array of saved current pointers
+	 * (one for each cpu). we need them at user->kernel transition,
+	 * while we save them at kernel->user transition
+	 */
+	new_ti = new->stack;
+	old_ti = old->stack;
+
+	current_thread_info_set[smp_processor_id()] = new_ti;
+	last = (_switch(old_ti, new_ti))->task;
+
+	local_irq_restore(flags);
+
+	return last;
+}
+
+/*
+ * Write out registers in core dump format, as defined by the
+ * struct user_regs_struct
+ */
+void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs)
+{
+	dest[0] = 0; /* r0 */
+	memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long));
+	dest[32] = regs->pc;
+	dest[33] = regs->sr;
+	dest[34] = 0;
+	dest[35] = 0;
+}
+
+unsigned long get_wchan(struct task_struct *p)
+{
+	/* TODO */
+
+	return 0;
+}