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/export.h>
  12 #include <linux/sched.h>
  13 #include <linux/pm.h>
  14 #include <linux/tick.h>
  15 #include <linux/bitops.h>
  16 #include <linux/ptrace.h>
  17 #include <asm/pgalloc.h>
  18 #include <linux/uaccess.h> /* for USER_DS macros */
  19 #include <asm/cacheflush.h>
  20
  21 void show_regs(struct pt_regs *regs)
  22 {
  23         pr_info(" Registers dump: mode=%X\r\n", regs->pt_mode);
  24         pr_info(" r1=%08lX, r2=%08lX, r3=%08lX, r4=%08lX\n",
  25                                 regs->r1, regs->r2, regs->r3, regs->r4);
  26         pr_info(" r5=%08lX, r6=%08lX, r7=%08lX, r8=%08lX\n",
  27                                 regs->r5, regs->r6, regs->r7, regs->r8);
  28         pr_info(" r9=%08lX, r10=%08lX, r11=%08lX, r12=%08lX\n",
  29                                 regs->r9, regs->r10, regs->r11, regs->r12);
  30         pr_info(" r13=%08lX, r14=%08lX, r15=%08lX, r16=%08lX\n",
  31                                 regs->r13, regs->r14, regs->r15, regs->r16);
  32         pr_info(" r17=%08lX, r18=%08lX, r19=%08lX, r20=%08lX\n",
  33                                 regs->r17, regs->r18, regs->r19, regs->r20);
  34         pr_info(" r21=%08lX, r22=%08lX, r23=%08lX, r24=%08lX\n",
  35                                 regs->r21, regs->r22, regs->r23, regs->r24);
  36         pr_info(" r25=%08lX, r26=%08lX, r27=%08lX, r28=%08lX\n",
  37                                 regs->r25, regs->r26, regs->r27, regs->r28);
  38         pr_info(" r29=%08lX, r30=%08lX, r31=%08lX, rPC=%08lX\n",
  39                                 regs->r29, regs->r30, regs->r31, regs->pc);
  40         pr_info(" msr=%08lX, ear=%08lX, esr=%08lX, fsr=%08lX\n",
  41                                 regs->msr, regs->ear, regs->esr, regs->fsr);
  42 }
  43
  44 void (*pm_power_off)(void) = NULL;
  45 EXPORT_SYMBOL(pm_power_off);
  46
  47 static int hlt_counter = 1;
  48
  49 void disable_hlt(void)
  50 {
  51         hlt_counter++;
  52 }
  53 EXPORT_SYMBOL(disable_hlt);
  54
  55 void enable_hlt(void)
  56 {
  57         hlt_counter--;
  58 }
  59 EXPORT_SYMBOL(enable_hlt);
  60
  61 static int __init nohlt_setup(char *__unused)
  62 {
  63         hlt_counter = 1;
  64         return 1;
  65 }
  66 __setup("nohlt", nohlt_setup);
  67
  68 static int __init hlt_setup(char *__unused)
  69 {
  70         hlt_counter = 0;
  71         return 1;
  72 }
  73 __setup("hlt", hlt_setup);
  74
  75 void default_idle(void)
  76 {
  77         if (likely(hlt_counter)) {
  78                 local_irq_disable();
  79                 stop_critical_timings();
  80                 cpu_relax();
  81                 start_critical_timings();
  82                 local_irq_enable();
  83         } else {
  84                 clear_thread_flag(TIF_POLLING_NRFLAG);
  85                 smp_mb__after_clear_bit();
  86                 local_irq_disable();
  87                 while (!need_resched())
  88                         cpu_sleep();
  89                 local_irq_enable();
  90                 set_thread_flag(TIF_POLLING_NRFLAG);
  91         }
  92 }
  93
  94 void cpu_idle(void)
  95 {
  96         set_thread_flag(TIF_POLLING_NRFLAG);
  97
  98         /* endless idle loop with no priority at all */
  99         while (1) {
 100                 tick_nohz_idle_enter();
 101                 rcu_idle_enter();
 102                 while (!need_resched())
 103                         default_idle();
 104                 rcu_idle_exit();
 105                 tick_nohz_idle_exit();
 106
 107                 schedule_preempt_disabled();
 108                 check_pgt_cache();
 109         }
 110 }
 111
 112 void flush_thread(void)
 113 {
 114 }
 115
 116 int copy_thread(unsigned long clone_flags, unsigned long usp,
 117                 unsigned long arg, struct task_struct *p)
 118 {
 119         struct pt_regs *childregs = task_pt_regs(p);
 120         struct thread_info *ti = task_thread_info(p);
 121
 122         if (unlikely(p->flags & PF_KTHREAD)) {
 123                 /* if we're creating a new kernel thread then just zeroing all
 124                  * the registers. That's OK for a brand new thread.*/
 125                 memset(childregs, 0, sizeof(struct pt_regs));
 126                 memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
 127                 ti->cpu_context.r1  = (unsigned long)childregs;
 128                 ti->cpu_context.r20 = (unsigned long)usp; /* fn */
 129                 ti->cpu_context.r19 = (unsigned long)arg;
 130                 childregs->pt_mode = 1;
 131                 local_save_flags(childregs->msr);
 132 #ifdef CONFIG_MMU
 133                 ti->cpu_context.msr = childregs->msr & ~MSR_IE;
 134 #endif
 135                 ti->cpu_context.r15 = (unsigned long)ret_from_kernel_thread - 8;
 136                 return 0;
 137         }
 138         *childregs = *current_pt_regs();
 139         if (usp)
 140                 childregs->r1 = usp;
 141
 142         memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
 143         ti->cpu_context.r1 = (unsigned long)childregs;
 144 #ifndef CONFIG_MMU
 145         ti->cpu_context.msr = (unsigned long)childregs->msr;
 146 #else
 147         childregs->msr |= MSR_UMS;
 148
 149         /* we should consider the fact that childregs is a copy of the parent
 150          * regs which were saved immediately after entering the kernel state
 151          * before enabling VM. This MSR will be restored in switch_to and
 152          * RETURN() and we want to have the right machine state there
 153          * specifically this state must have INTs disabled before and enabled
 154          * after performing rtbd
 155          * compose the right MSR for RETURN(). It will work for switch_to also
 156          * excepting for VM and UMS
 157          * don't touch UMS , CARRY and cache bits
 158          * right now MSR is a copy of parent one */
 159         childregs->msr &= ~MSR_EIP;
 160         childregs->msr |= MSR_IE;
 161         childregs->msr &= ~MSR_VM;
 162         childregs->msr |= MSR_VMS;
 163         childregs->msr |= MSR_EE; /* exceptions will be enabled*/
 164
 165         ti->cpu_context.msr = (childregs->msr|MSR_VM);
 166         ti->cpu_context.msr &= ~MSR_UMS; /* switch_to to kernel mode */
 167         ti->cpu_context.msr &= ~MSR_IE;
 168 #endif
 169         ti->cpu_context.r15 = (unsigned long)ret_from_fork - 8;
 170
 171         /*
 172          *  r21 is the thread reg, r10 is 6th arg to clone
 173          *  which contains TLS area
 174          */
 175         if (clone_flags & CLONE_SETTLS)
 176                 childregs->r21 = childregs->r10;
 177
 178         return 0;
 179 }
 180
 181 #ifndef CONFIG_MMU
 182 /*
 183  * Return saved PC of a blocked thread.
 184  */
 185 unsigned long thread_saved_pc(struct task_struct *tsk)
 186 {
 187         struct cpu_context *ctx =
 188                 &(((struct thread_info *)(tsk->stack))->cpu_context);
 189
 190         /* Check whether the thread is blocked in resume() */
 191         if (in_sched_functions(ctx->r15))
 192                 return (unsigned long)ctx->r15;
 193         else
 194                 return ctx->r14;
 195 }
 196 #endif
 197
 198 unsigned long get_wchan(struct task_struct *p)
 199 {
 200 /* TBD (used by procfs) */
 201         return 0;
 202 }
 203
 204 /* Set up a thread for executing a new program */
 205 void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp)
 206 {
 207         regs->pc = pc;
 208         regs->r1 = usp;
 209         regs->pt_mode = 0;
 210 #ifdef CONFIG_MMU
 211         regs->msr |= MSR_UMS;
 212         regs->msr &= ~MSR_VM;
 213 #endif
 214 }
 215
 216 #ifdef CONFIG_MMU
 217 #include <linux/elfcore.h>
 218 /*
 219  * Set up a thread for executing a new program
 220  */
 221 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs)
 222 {
 223         return 0; /* MicroBlaze has no separate FPU registers */
 224 }
 225 #endif /* CONFIG_MMU */