C6X: process management
Original port to early 2.6 kernel using TI COFF toolchain.
Brought up to date by Mark Salter <msalter@redhat.com>
Signed-off-by: Aurelien Jacquiot <a-jacquiot@ti.com>
Signed-off-by: Mark Salter <msalter@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/arch/c6x/kernel/process.c b/arch/c6x/kernel/process.c
new file mode 100644
index 0000000..aa65c87
--- /dev/null
+++ b/arch/c6x/kernel/process.c
@@ -0,0 +1,263 @@
+/*
+ * Port on Texas Instruments TMS320C6x architecture
+ *
+ * Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
+ * Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+#include <linux/module.h>
+#include <linux/unistd.h>
+#include <linux/ptrace.h>
+#include <linux/init_task.h>
+#include <linux/tick.h>
+#include <linux/mqueue.h>
+#include <linux/syscalls.h>
+#include <linux/reboot.h>
+
+#include <asm/syscalls.h>
+
+/* hooks for board specific support */
+void (*c6x_restart)(void);
+void (*c6x_halt)(void);
+
+extern asmlinkage void ret_from_fork(void);
+
+static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
+static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
+
+/*
+ * Initial thread structure.
+ */
+union thread_union init_thread_union __init_task_data = {
+ INIT_THREAD_INFO(init_task)
+};
+
+/*
+ * Initial task structure.
+ */
+struct task_struct init_task = INIT_TASK(init_task);
+EXPORT_SYMBOL(init_task);
+
+/*
+ * power off function, if any
+ */
+void (*pm_power_off)(void);
+EXPORT_SYMBOL(pm_power_off);
+
+static void c6x_idle(void)
+{
+ unsigned long tmp;
+
+ /*
+ * Put local_irq_enable and idle in same execute packet
+ * to make them atomic and avoid race to idle with
+ * interrupts enabled.
+ */
+ asm volatile (" mvc .s2 CSR,%0\n"
+ " or .d2 1,%0,%0\n"
+ " mvc .s2 %0,CSR\n"
+ "|| idle\n"
+ : "=b"(tmp));
+}
+
+/*
+ * The idle loop for C64x
+ */
+void cpu_idle(void)
+{
+ /* endless idle loop with no priority at all */
+ while (1) {
+ tick_nohz_stop_sched_tick(1);
+ while (1) {
+ local_irq_disable();
+ if (need_resched()) {
+ local_irq_enable();
+ break;
+ }
+ c6x_idle(); /* enables local irqs */
+ }
+ tick_nohz_restart_sched_tick();
+
+ preempt_enable_no_resched();
+ schedule();
+ preempt_disable();
+ }
+}
+
+static void halt_loop(void)
+{
+ printk(KERN_EMERG "System Halted, OK to turn off power\n");
+ local_irq_disable();
+ while (1)
+ asm volatile("idle\n");
+}
+
+void machine_restart(char *__unused)
+{
+ if (c6x_restart)
+ c6x_restart();
+ halt_loop();
+}
+
+void machine_halt(void)
+{
+ if (c6x_halt)
+ c6x_halt();
+ halt_loop();
+}
+
+void machine_power_off(void)
+{
+ if (pm_power_off)
+ pm_power_off();
+ halt_loop();
+}
+
+static void kernel_thread_helper(int dummy, void *arg, int (*fn)(void *))
+{
+ do_exit(fn(arg));
+}
+
+/*
+ * Create a kernel thread
+ */
+int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
+{
+ struct pt_regs regs;
+
+ /*
+ * copy_thread sets a4 to zero (child return from fork)
+ * so we can't just set things up to directly return to
+ * fn.
+ */
+ memset(®s, 0, sizeof(regs));
+ regs.b4 = (unsigned long) arg;
+ regs.a6 = (unsigned long) fn;
+ regs.pc = (unsigned long) kernel_thread_helper;
+ local_save_flags(regs.csr);
+ regs.csr |= 1;
+ regs.tsr = 5; /* Set GEE and GIE in TSR */
+
+ /* Ok, create the new process.. */
+ return do_fork(flags | CLONE_VM | CLONE_UNTRACED, -1, ®s,
+ 0, NULL, NULL);
+}
+EXPORT_SYMBOL(kernel_thread);
+
+void flush_thread(void)
+{
+}
+
+void exit_thread(void)
+{
+}
+
+SYSCALL_DEFINE1(c6x_clone, struct pt_regs *, regs)
+{
+ unsigned long clone_flags;
+ unsigned long newsp;
+
+ /* syscall puts clone_flags in A4 and usp in B4 */
+ clone_flags = regs->orig_a4;
+ if (regs->b4)
+ newsp = regs->b4;
+ else
+ newsp = regs->sp;
+
+ return do_fork(clone_flags, newsp, regs, 0, (int __user *)regs->a6,
+ (int __user *)regs->b6);
+}
+
+/*
+ * Do necessary setup to start up a newly executed thread.
+ */
+void start_thread(struct pt_regs *regs, unsigned int pc, unsigned long usp)
+{
+ /*
+ * The binfmt loader will setup a "full" stack, but the C6X
+ * operates an "empty" stack. So we adjust the usp so that
+ * argc doesn't get destroyed if an interrupt is taken before
+ * it is read from the stack.
+ *
+ * NB: Library startup code needs to match this.
+ */
+ usp -= 8;
+
+ set_fs(USER_DS);
+ regs->pc = pc;
+ regs->sp = usp;
+ regs->tsr |= 0x40; /* set user mode */
+ current->thread.usp = usp;
+}
+
+/*
+ * Copy a new thread context in its stack.
+ */
+int copy_thread(unsigned long clone_flags, unsigned long usp,
+ unsigned long ustk_size,
+ struct task_struct *p, struct pt_regs *regs)
+{
+ struct pt_regs *childregs;
+
+ childregs = task_pt_regs(p);
+
+ *childregs = *regs;
+ childregs->a4 = 0;
+
+ if (usp == -1)
+ /* case of __kernel_thread: we return to supervisor space */
+ childregs->sp = (unsigned long)(childregs + 1);
+ else
+ /* Otherwise use the given stack */
+ childregs->sp = usp;
+
+ /* Set usp/ksp */
+ p->thread.usp = childregs->sp;
+ /* switch_to uses stack to save/restore 14 callee-saved regs */
+ thread_saved_ksp(p) = (unsigned long)childregs - 8;
+ p->thread.pc = (unsigned int) ret_from_fork;
+ p->thread.wchan = (unsigned long) ret_from_fork;
+#ifdef __DSBT__
+ {
+ unsigned long dp;
+
+ asm volatile ("mv .S2 b14,%0\n" : "=b"(dp));
+
+ thread_saved_dp(p) = dp;
+ if (usp == -1)
+ childregs->dp = dp;
+ }
+#endif
+ return 0;
+}
+
+/*
+ * c6x_execve() executes a new program.
+ */
+SYSCALL_DEFINE4(c6x_execve, const char __user *, name,
+ const char __user *const __user *, argv,
+ const char __user *const __user *, envp,
+ struct pt_regs *, regs)
+{
+ int error;
+ char *filename;
+
+ filename = getname(name);
+ error = PTR_ERR(filename);
+ if (IS_ERR(filename))
+ goto out;
+
+ error = do_execve(filename, argv, envp, regs);
+ putname(filename);
+out:
+ return error;
+}
+
+unsigned long get_wchan(struct task_struct *p)
+{
+ return p->thread.wchan;
+}