v4.19.13 snapshot.
diff --git a/arch/c6x/kernel/process.c b/arch/c6x/kernel/process.c
new file mode 100644
index 0000000..c4ecb24
--- /dev/null
+++ b/arch/c6x/kernel/process.c
@@ -0,0 +1,155 @@
+/*
+ * 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 <linux/sched/task.h>
+#include <linux/sched/task_stack.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);
+extern asmlinkage void ret_from_kernel_thread(void);
+
+/*
+ * power off function, if any
+ */
+void (*pm_power_off)(void);
+EXPORT_SYMBOL(pm_power_off);
+
+void arch_cpu_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));
+}
+
+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();
+}
+
+void flush_thread(void)
+{
+}
+
+/*
+ * 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;
+
+ 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 *childregs;
+
+ childregs = task_pt_regs(p);
+
+ if (unlikely(p->flags & PF_KTHREAD)) {
+ /* case of __kernel_thread: we return to supervisor space */
+ memset(childregs, 0, sizeof(struct pt_regs));
+ childregs->sp = (unsigned long)(childregs + 1);
+ p->thread.pc = (unsigned long) ret_from_kernel_thread;
+ childregs->a0 = usp; /* function */
+ childregs->a1 = ustk_size; /* argument */
+ } else {
+ /* Otherwise use the given stack */
+ *childregs = *current_pt_regs();
+ if (usp)
+ childregs->sp = usp;
+ p->thread.pc = (unsigned long) ret_from_fork;
+ }
+
+ /* Set usp/ksp */
+ p->thread.usp = childregs->sp;
+ thread_saved_ksp(p) = (unsigned long)childregs - 8;
+ p->thread.wchan = p->thread.pc;
+#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;
+}
+
+unsigned long get_wchan(struct task_struct *p)
+{
+ return p->thread.wchan;
+}