Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 * This file is subject to the terms and conditions of the GNU General Public

 * License.  See the file "COPYING" in the main directory of this archive

 * for more details.

 *

 * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others.

 * Copyright (C) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org)

 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.

 * Copyright (C) 2004 Thiemo Seufer

 */

#include <linux/errno.h>

#include <linux/module.h>

#include <linux/sched.h>

#include <linux/tick.h>

#include <linux/kernel.h>

#include <linux/mm.h>

#include <linux/stddef.h>

#include <linux/unistd.h>

#include <linux/ptrace.h>

#include <linux/slab.h>

#include <linux/mman.h>

#include <linux/personality.h>

#include <linux/sys.h>

#include <linux/user.h>

#include <linux/a.out.h>

#include <linux/init.h>

#include <linux/completion.h>

#include <linux/kallsyms.h>

#include <linux/random.h>

#include <asm/asm.h>

#include <asm/bootinfo.h>

#include <asm/cpu.h>

#include <asm/dsp.h>

#include <asm/fpu.h>

#include <asm/pgtable.h>

#include <asm/system.h>

#include <asm/mipsregs.h>

#include <asm/processor.h>

#include <asm/uaccess.h>

#include <asm/io.h>

#include <asm/elf.h>

#include <asm/isadep.h>

#include <asm/inst.h>

#include <asm/stacktrace.h>

/*

 * The idle thread. There's no useful work to be done, so just try to conserve

 * power and have a low exit latency (ie sit in a loop waiting for somebody to

 * say that they'd like to reschedule)

 */

void __noreturn cpu_idle(void)

{

        /* endless idle loop with no priority at all */

        while (1) {

                tick_nohz_stop_sched_tick();

                while (!need_resched()) {

#ifdef CONFIG_SMTC_IDLE_HOOK_DEBUG

                        extern void smtc_idle_loop_hook(void);

                        smtc_idle_loop_hook();

#endif

                        if (cpu_wait)

                                (*cpu_wait)();

                }

                tick_nohz_restart_sched_tick();

                preempt_enable_no_resched();

                schedule();

                preempt_disable();

        }

}

asmlinkage void ret_from_fork(void);

void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)

{

        unsigned long status;

        /* New thread loses kernel privileges. */

        status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK);

#ifdef CONFIG_64BIT

        status |= test_thread_flag(TIF_32BIT_REGS) ? 0 : ST0_FR;

#endif

        status |= KU_USER;

        regs->cp0_status = status;

        clear_used_math();

        clear_fpu_owner();

        if (cpu_has_dsp)

                __init_dsp();

        regs->cp0_epc = pc;

        regs->regs[29] = sp;

        current_thread_info()->addr_limit = USER_DS;

}

void exit_thread(void)

{

}

void flush_thread(void)

{

}

int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,

        unsigned long unused, struct task_struct *p, struct pt_regs *regs)

{

        struct thread_info *ti = task_thread_info(p);

        struct pt_regs *childregs;

        long childksp;

        p->set_child_tid = p->clear_child_tid = NULL;

        childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;

        preempt_disable();

        if (is_fpu_owner())

                save_fp(p);

        if (cpu_has_dsp)

                save_dsp(p);

        preempt_enable();

        /* set up new TSS. */

        childregs = (struct pt_regs *) childksp - 1;

        *childregs = *regs;

        childregs->regs[7] = 0;  /* Clear error flag */

#if defined(CONFIG_BINFMT_IRIX)

        if (current->personality != PER_LINUX) {

                /* Under IRIX things are a little different. */

                childregs->regs[3] = 1;

                regs->regs[3] = 0;

        }

#endif

        childregs->regs[2] = 0;  /* Child gets zero as return value */

        regs->regs[2] = p->pid;

        if (childregs->cp0_status & ST0_CU0) {

                childregs->regs[28] = (unsigned long) ti;

                childregs->regs[29] = childksp;

                ti->addr_limit = KERNEL_DS;

        } else {

                childregs->regs[29] = usp;

                ti->addr_limit = USER_DS;

        }

        p->thread.reg29 = (unsigned long) childregs;

        p->thread.reg31 = (unsigned long) ret_from_fork;

        /*

         * New tasks lose permission to use the fpu. This accelerates context

         * switching for most programs since they don't use the fpu.

         */

        p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);

        childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);

        clear_tsk_thread_flag(p, TIF_USEDFPU);

#ifdef CONFIG_MIPS_MT_FPAFF

        /*

         * FPU affinity support is cleaner if we track the

         * user-visible CPU affinity from the very beginning.

         * The generic cpus_allowed mask will already have

         * been copied from the parent before copy_thread

         * is invoked.

         */

        p->thread.user_cpus_allowed = p->cpus_allowed;

#endif /* CONFIG_MIPS_MT_FPAFF */

        if (clone_flags & CLONE_SETTLS)

                ti->tp_value = regs->regs[7];

        return 0;

}

/* Fill in the fpu structure for a core dump.. */

int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)

{

        memcpy(r, &current->thread.fpu, sizeof(current->thread.fpu));

        return 1;

}

void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs)

{

        int i;

        for (i = 0; i < EF_R0; i++)

                gp[i] = 0;

        gp[EF_R0] = 0;

        for (i = 1; i <= 31; i++)

                gp[EF_R0 + i] = regs->regs[i];

        gp[EF_R26] = 0;

        gp[EF_R27] = 0;

        gp[EF_LO] = regs->lo;

        gp[EF_HI] = regs->hi;

        gp[EF_CP0_EPC] = regs->cp0_epc;

        gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;

        gp[EF_CP0_STATUS] = regs->cp0_status;

        gp[EF_CP0_CAUSE] = regs->cp0_cause;

#ifdef EF_UNUSED0

        gp[EF_UNUSED0] = 0;

#endif

}

int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)

{

        elf_dump_regs(*regs, task_pt_regs(tsk));

        return 1;

}

int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr)

{

        memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));

        return 1;

}

/*

 * Create a kernel thread

 */

static void __noreturn kernel_thread_helper(void *arg, int (*fn)(void *))

{

        do_exit(fn(arg));

}

long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)

{

        struct pt_regs regs;

        memset(&regs, 0, sizeof(regs));

        regs.regs[4] = (unsigned long) arg;

        regs.regs[5] = (unsigned long) fn;

        regs.cp0_epc = (unsigned long) kernel_thread_helper;

        regs.cp0_status = read_c0_status();

#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)

        regs.cp0_status = (regs.cp0_status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |

                          ((regs.cp0_status & (ST0_KUC | ST0_IEC)) << 2);

#else

        regs.cp0_status |= ST0_EXL;

#endif

        /* Ok, create the new process.. */

        return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);

}

/*

 *

 */

struct mips_frame_info {

        void            *func;

        unsigned long   func_size;

        int             frame_size;

        int             pc_offset;

};

static inline int is_ra_save_ins(union mips_instruction *ip)

{

        /* sw / sd $ra, offset($sp) */

        return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) &&

                ip->i_format.rs == 29 &&

                ip->i_format.rt == 31;

}

static inline int is_jal_jalr_jr_ins(union mips_instruction *ip)

{

        if (ip->j_format.opcode == jal_op)

                return 1;

        if (ip->r_format.opcode != spec_op)

                return 0;

        return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;

}

static inline int is_sp_move_ins(union mips_instruction *ip)

{

        /* addiu/daddiu sp,sp,-imm */

        if (ip->i_format.rs != 29 || ip->i_format.rt != 29)

                return 0;

        if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)

                return 1;

        return 0;

}

static int get_frame_info(struct mips_frame_info *info)

{

        union mips_instruction *ip = info->func;

        unsigned max_insns = info->func_size / sizeof(union mips_instruction);

        unsigned i;

        info->pc_offset = -1;

        info->frame_size = 0;

        if (!ip)

                goto err;

        if (max_insns == 0)

                max_insns = 128U;       /* unknown function size */

        max_insns = min(128U, max_insns);

        for (i = 0; i < max_insns; i++, ip++) {

                if (is_jal_jalr_jr_ins(ip))

                        break;

                if (!info->frame_size) {

                        if (is_sp_move_ins(ip))

                                info->frame_size = - ip->i_format.simmediate;

                        continue;

                }

                if (info->pc_offset == -1 && is_ra_save_ins(ip)) {

                        info->pc_offset =

                                ip->i_format.simmediate / sizeof(long);

                        break;

                }

        }

        if (info->frame_size && info->pc_offset >= 0) /* nested */

                return 0;

        if (info->pc_offset < 0) /* leaf */

                return 1;

        /* prologue seems boggus... */

err:

        return -1;

}

static struct mips_frame_info schedule_mfi __read_mostly;

static int __init frame_info_init(void)

{

        unsigned long size = 0;

#ifdef CONFIG_KALLSYMS

        unsigned long ofs;

        kallsyms_lookup_size_offset((unsigned long)schedule, &size, &ofs);

#endif

        schedule_mfi.func = schedule;

        schedule_mfi.func_size = size;

        get_frame_info(&schedule_mfi);

        /*

         * Without schedule() frame info, result given by

         * thread_saved_pc() and get_wchan() are not reliable.

         */

        if (schedule_mfi.pc_offset < 0)

                printk("Can't analyze schedule() prologue at %p\n", schedule);

        return 0;

}

arch_initcall(frame_info_init);

/*

 * Return saved PC of a blocked thread.

 */

unsigned long thread_saved_pc(struct task_struct *tsk)

{

        struct thread_struct *t = &tsk->thread;

        /* New born processes are a special case */

        if (t->reg31 == (unsigned long) ret_from_fork)

                return t->reg31;

        if (schedule_mfi.pc_offset < 0)

                return 0;

        return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];

}

#ifdef CONFIG_KALLSYMS

/* used by show_backtrace() */

unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,

                           unsigned long pc, unsigned long *ra)

{

        unsigned long stack_page;

        struct mips_frame_info info;

        unsigned long size, ofs;

        int leaf;

        extern void ret_from_irq(void);

        extern void ret_from_exception(void);

        stack_page = (unsigned long)task_stack_page(task);

        if (!stack_page)

                return 0;

        /*

         * If we reached the bottom of interrupt context,

         * return saved pc in pt_regs.

         */

        if (pc == (unsigned long)ret_from_irq ||

            pc == (unsigned long)ret_from_exception) {

                struct pt_regs *regs;

                if (*sp >= stack_page &&

                    *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {

                        regs = (struct pt_regs *)*sp;

                        pc = regs->cp0_epc;

                        if (__kernel_text_address(pc)) {

                                *sp = regs->regs[29];

                                *ra = regs->regs[31];

                                return pc;

                        }

                }

                return 0;

        }

        if (!kallsyms_lookup_size_offset(pc, &size, &ofs))

                return 0;

        /*

         * Return ra if an exception occured at the first instruction

         */

        if (unlikely(ofs == 0)) {

                pc = *ra;

                *ra = 0;

                return pc;

        }

        info.func = (void *)(pc - ofs);

        info.func_size = ofs;   /* analyze from start to ofs */

        leaf = get_frame_info(&info);

        if (leaf < 0)

                return 0;

        if (*sp < stack_page ||

            *sp + info.frame_size > stack_page + THREAD_SIZE - 32)

                return 0;

        if (leaf)

                /*

                 * For some extreme cases, get_frame_info() can

                 * consider wrongly a nested function as a leaf

                 * one. In that cases avoid to return always the

                 * same value.

                 */

                pc = pc != *ra ? *ra : 0;

        else

                pc = ((unsigned long *)(*sp))[info.pc_offset];

        *sp += info.frame_size;

        *ra = 0;

        return __kernel_text_address(pc) ? pc : 0;

}

#endif

/*

 * get_wchan - a maintenance nightmare^W^Wpain in the ass ...

 */

unsigned long get_wchan(struct task_struct *task)

{

        unsigned long pc = 0;

#ifdef CONFIG_KALLSYMS

        unsigned long sp;

        unsigned long ra = 0;

#endif

        if (!task || task == current || task->state == TASK_RUNNING)

                goto out;

        if (!task_stack_page(task))

                goto out;

        pc = thread_saved_pc(task);

#ifdef CONFIG_KALLSYMS

        sp = task->thread.reg29 + schedule_mfi.frame_size;

        while (in_sched_functions(pc))

                pc = unwind_stack(task, &sp, pc, &ra);

#endif

out:

        return pc;

}

/*

 * Don't forget that the stack pointer must be aligned on a 8 bytes

 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.

 */

unsigned long arch_align_stack(unsigned long sp)

{

        if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)

                sp -= get_random_int() & ~PAGE_MASK;

        return sp & ALMASK;

}