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