LXR linux/arch/microblaze/kernel/process.c

   1/*
   2 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
   3 * Copyright (C) 2008-2009 PetaLogix
   4 * Copyright (C) 2006 Atmark Techno, Inc.
   5 *
   6 * This file is subject to the terms and conditions of the GNU General Public
   7 * License. See the file "COPYING" in the main directory of this archive
   8 * for more details.
   9 */
  10
  11#include <linux/module.h>
  12#include <linux/sched.h>
  13#include <linux/pm.h>
  14#include <linux/tick.h>
  15#include <linux/bitops.h>
  16#include <asm/system.h>
  17#include <asm/pgalloc.h>
  18#include <asm/uaccess.h> /* for USER_DS macros */
  19#include <asm/cacheflush.h>
  20
  21void show_regs(struct pt_regs *regs)
  22{
  23        printk(KERN_INFO " Registers dump: mode=%X\r\n", regs->pt_mode);
  24        printk(KERN_INFO " r1=%08lX, r2=%08lX, r3=%08lX, r4=%08lX\n",
  25                                regs->r1, regs->r2, regs->r3, regs->r4);
  26        printk(KERN_INFO " r5=%08lX, r6=%08lX, r7=%08lX, r8=%08lX\n",
  27                                regs->r5, regs->r6, regs->r7, regs->r8);
  28        printk(KERN_INFO " r9=%08lX, r10=%08lX, r11=%08lX, r12=%08lX\n",
  29                                regs->r9, regs->r10, regs->r11, regs->r12);
  30        printk(KERN_INFO " r13=%08lX, r14=%08lX, r15=%08lX, r16=%08lX\n",
  31                                regs->r13, regs->r14, regs->r15, regs->r16);
  32        printk(KERN_INFO " r17=%08lX, r18=%08lX, r19=%08lX, r20=%08lX\n",
  33                                regs->r17, regs->r18, regs->r19, regs->r20);
  34        printk(KERN_INFO " r21=%08lX, r22=%08lX, r23=%08lX, r24=%08lX\n",
  35                                regs->r21, regs->r22, regs->r23, regs->r24);
  36        printk(KERN_INFO " r25=%08lX, r26=%08lX, r27=%08lX, r28=%08lX\n",
  37                                regs->r25, regs->r26, regs->r27, regs->r28);
  38        printk(KERN_INFO " r29=%08lX, r30=%08lX, r31=%08lX, rPC=%08lX\n",
  39                                regs->r29, regs->r30, regs->r31, regs->pc);
  40        printk(KERN_INFO " msr=%08lX, ear=%08lX, esr=%08lX, fsr=%08lX\n",
  41                                regs->msr, regs->ear, regs->esr, regs->fsr);
  42}
  43
  44void (*pm_idle)(void);
  45void (*pm_power_off)(void) = NULL;
  46EXPORT_SYMBOL(pm_power_off);
  47
  48static int hlt_counter = 1;
  49
  50void disable_hlt(void)
  51{
  52        hlt_counter++;
  53}
  54EXPORT_SYMBOL(disable_hlt);
  55
  56void enable_hlt(void)
  57{
  58        hlt_counter--;
  59}
  60EXPORT_SYMBOL(enable_hlt);
  61
  62static int __init nohlt_setup(char *__unused)
  63{
  64        hlt_counter = 1;
  65        return 1;
  66}
  67__setup("nohlt", nohlt_setup);
  68
  69static int __init hlt_setup(char *__unused)
  70{
  71        hlt_counter = 0;
  72        return 1;
  73}
  74__setup("hlt", hlt_setup);
  75
  76void default_idle(void)
  77{
  78        if (likely(hlt_counter)) {
  79                local_irq_disable();
  80                stop_critical_timings();
  81                cpu_relax();
  82                start_critical_timings();
  83                local_irq_enable();
  84        } else {
  85                clear_thread_flag(TIF_POLLING_NRFLAG);
  86                smp_mb__after_clear_bit();
  87                local_irq_disable();
  88                while (!need_resched())
  89                        cpu_sleep();
  90                local_irq_enable();
  91                set_thread_flag(TIF_POLLING_NRFLAG);
  92        }
  93}
  94
  95void cpu_idle(void)
  96{
  97        set_thread_flag(TIF_POLLING_NRFLAG);
  98
  99        /* endless idle loop with no priority at all */
 100        while (1) {
 101                void (*idle)(void) = pm_idle;
 102
 103                if (!idle)
 104                        idle = default_idle;
 105
 106                tick_nohz_stop_sched_tick(1);
 107                while (!need_resched())
 108                        idle();
 109                tick_nohz_restart_sched_tick();
 110
 111                preempt_enable_no_resched();
 112                schedule();
 113                preempt_disable();
 114                check_pgt_cache();
 115        }
 116}
 117
 118void flush_thread(void)
 119{
 120}
 121
 122int copy_thread(unsigned long clone_flags, unsigned long usp,
 123                unsigned long unused,
 124                struct task_struct *p, struct pt_regs *regs)
 125{
 126        struct pt_regs *childregs = task_pt_regs(p);
 127        struct thread_info *ti = task_thread_info(p);
 128
 129        *childregs = *regs;
 130        if (user_mode(regs))
 131                childregs->r1 = usp;
 132        else
 133                childregs->r1 = ((unsigned long) ti) + THREAD_SIZE;
 134
 135#ifndef CONFIG_MMU
 136        memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
 137        ti->cpu_context.r1 = (unsigned long)childregs;
 138        ti->cpu_context.msr = (unsigned long)childregs->msr;
 139#else
 140
 141        /* if creating a kernel thread then update the current reg (we don't
 142         * want to use the parent's value when restoring by POP_STATE) */
 143        if (kernel_mode(regs))
 144                /* save new current on stack to use POP_STATE */
 145                childregs->CURRENT_TASK = (unsigned long)p;
 146        /* if returning to user then use the parent's value of this register */
 147
 148        /* if we're creating a new kernel thread then just zeroing all
 149         * the registers. That's OK for a brand new thread.*/
 150        /* Pls. note that some of them will be restored in POP_STATE */
 151        if (kernel_mode(regs))
 152                memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
 153        /* if this thread is created for fork/vfork/clone, then we want to
 154         * restore all the parent's context */
 155        /* in addition to the registers which will be restored by POP_STATE */
 156        else {
 157                ti->cpu_context = *(struct cpu_context *)regs;
 158                childregs->msr |= MSR_UMS;
 159        }
 160
 161        /* FIXME STATE_SAVE_PT_OFFSET; */
 162        ti->cpu_context.r1  = (unsigned long)childregs;
 163        /* we should consider the fact that childregs is a copy of the parent
 164         * regs which were saved immediately after entering the kernel state
 165         * before enabling VM. This MSR will be restored in switch_to and
 166         * RETURN() and we want to have the right machine state there
 167         * specifically this state must have INTs disabled before and enabled
 168         * after performing rtbd
 169         * compose the right MSR for RETURN(). It will work for switch_to also
 170         * excepting for VM and UMS
 171         * don't touch UMS , CARRY and cache bits
 172         * right now MSR is a copy of parent one */
 173        childregs->msr |= MSR_BIP;
 174        childregs->msr &= ~MSR_EIP;
 175        childregs->msr |= MSR_IE;
 176        childregs->msr &= ~MSR_VM;
 177        childregs->msr |= MSR_VMS;
 178        childregs->msr |= MSR_EE; /* exceptions will be enabled*/
 179
 180        ti->cpu_context.msr = (childregs->msr|MSR_VM);
 181        ti->cpu_context.msr &= ~MSR_UMS; /* switch_to to kernel mode */
 182#endif
 183        ti->cpu_context.r15 = (unsigned long)ret_from_fork - 8;
 184
 185        if (clone_flags & CLONE_SETTLS)
 186                ;
 187
 188        return 0;
 189}
 190
 191#ifndef CONFIG_MMU
 192/*
 193 * Return saved PC of a blocked thread.
 194 */
 195unsigned long thread_saved_pc(struct task_struct *tsk)
 196{
 197        struct cpu_context *ctx =
 198                &(((struct thread_info *)(tsk->stack))->cpu_context);
 199
 200        /* Check whether the thread is blocked in resume() */
 201        if (in_sched_functions(ctx->r15))
 202                return (unsigned long)ctx->r15;
 203        else
 204                return ctx->r14;
 205}
 206#endif
 207
 208static void kernel_thread_helper(int (*fn)(void *), void *arg)
 209{
 210        fn(arg);
 211        do_exit(-1);
 212}
 213
 214int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 215{
 216        struct pt_regs regs;
 217
 218        memset(&regs, 0, sizeof(regs));
 219        /* store them in non-volatile registers */
 220        regs.r5 = (unsigned long)fn;
 221        regs.r6 = (unsigned long)arg;
 222        local_save_flags(regs.msr);
 223        regs.pc = (unsigned long)kernel_thread_helper;
 224        regs.pt_mode = 1;
 225
 226        return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
 227                        &regs, 0, NULL, NULL);
 228}
 229EXPORT_SYMBOL_GPL(kernel_thread);
 230
 231unsigned long get_wchan(struct task_struct *p)
 232{
 233/* TBD (used by procfs) */
 234        return 0;
 235}
 236
 237/* Set up a thread for executing a new program */
 238void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp)
 239{
 240        set_fs(USER_DS);
 241        regs->pc = pc;
 242        regs->r1 = usp;
 243        regs->pt_mode = 0;
 244#ifdef CONFIG_MMU
 245        regs->msr |= MSR_UMS;
 246#endif
 247}
 248
 249#ifdef CONFIG_MMU
 250#include <linux/elfcore.h>
 251/*
 252 * Set up a thread for executing a new program
 253 */
 254int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs)
 255{
 256        return 0; /* MicroBlaze has no separate FPU registers */
 257}
 258#endif /* CONFIG_MMU */
 259