| /* |
| * 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_idle_enter(); |
| rcu_idle_enter(); |
| while (1) { |
| local_irq_disable(); |
| if (need_resched()) { |
| local_irq_enable(); |
| break; |
| } |
| c6x_idle(); /* enables local irqs */ |
| } |
| rcu_idle_exit(); |
| tick_nohz_idle_exit(); |
| |
| 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; |
| } |