diff options
Diffstat (limited to 'arch/c6x/kernel/process.c')
| -rw-r--r-- | arch/c6x/kernel/process.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/arch/c6x/kernel/process.c b/arch/c6x/kernel/process.c new file mode 100644 index 000000000000..aa65c879323b --- /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; +} |