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/pgalloc.h> 17 #include <asm/uaccess.h> /* for USER_DS macros */ 18 #include <asm/cacheflush.h> 19 20 void show_regs(struct pt_regs *regs) 21 { 22 printk(KERN_INFO " Registers dump: mode=%X\r\n", regs->pt_mode); 23 printk(KERN_INFO " r1=%08lX, r2=%08lX, r3=%08lX, r4=%08lX\n", 24 regs->r1, regs->r2, regs->r3, regs->r4); 25 printk(KERN_INFO " r5=%08lX, r6=%08lX, r7=%08lX, r8=%08lX\n", 26 regs->r5, regs->r6, regs->r7, regs->r8); 27 printk(KERN_INFO " r9=%08lX, r10=%08lX, r11=%08lX, r12=%08lX\n", 28 regs->r9, regs->r10, regs->r11, regs->r12); 29 printk(KERN_INFO " r13=%08lX, r14=%08lX, r15=%08lX, r16=%08lX\n", 30 regs->r13, regs->r14, regs->r15, regs->r16); 31 printk(KERN_INFO " r17=%08lX, r18=%08lX, r19=%08lX, r20=%08lX\n", 32 regs->r17, regs->r18, regs->r19, regs->r20); 33 printk(KERN_INFO " r21=%08lX, r22=%08lX, r23=%08lX, r24=%08lX\n", 34 regs->r21, regs->r22, regs->r23, regs->r24); 35 printk(KERN_INFO " r25=%08lX, r26=%08lX, r27=%08lX, r28=%08lX\n", 36 regs->r25, regs->r26, regs->r27, regs->r28); 37 printk(KERN_INFO " r29=%08lX, r30=%08lX, r31=%08lX, rPC=%08lX\n", 38 regs->r29, regs->r30, regs->r31, regs->pc); 39 printk(KERN_INFO " msr=%08lX, ear=%08lX, esr=%08lX, fsr=%08lX\n", 40 regs->msr, regs->ear, regs->esr, regs->fsr); 41 } 42 43 void (*pm_idle)(void); 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 void (*idle)(void) = pm_idle; 101 102 if (!idle) 103 idle = default_idle; 104 105 tick_nohz_idle_enter(); 106 rcu_idle_enter(); 107 while (!need_resched()) 108 idle(); 109 rcu_idle_exit(); 110 tick_nohz_idle_exit(); 111 112 schedule_preempt_disabled(); 113 check_pgt_cache(); 114 } 115 } 116 117 void flush_thread(void) 118 { 119 } 120 121 int copy_thread(unsigned long clone_flags, unsigned long usp, 122 unsigned long unused, 123 struct task_struct *p, struct pt_regs *regs) 124 { 125 struct pt_regs *childregs = task_pt_regs(p); 126 struct thread_info *ti = task_thread_info(p); 127 128 *childregs = *regs; 129 if (user_mode(regs)) 130 childregs->r1 = usp; 131 else 132 childregs->r1 = ((unsigned long) ti) + THREAD_SIZE; 133 134 #ifndef CONFIG_MMU 135 memset(&ti->cpu_context, 0, sizeof(struct cpu_context)); 136 ti->cpu_context.r1 = (unsigned long)childregs; 137 ti->cpu_context.msr = (unsigned long)childregs->msr; 138 #else 139 140 /* if creating a kernel thread then update the current reg (we don't 141 * want to use the parent's value when restoring by POP_STATE) */ 142 if (kernel_mode(regs)) 143 /* save new current on stack to use POP_STATE */ 144 childregs->CURRENT_TASK = (unsigned long)p; 145 /* if returning to user then use the parent's value of this register */ 146 147 /* if we're creating a new kernel thread then just zeroing all 148 * the registers. That's OK for a brand new thread.*/ 149 /* Pls. note that some of them will be restored in POP_STATE */ 150 if (kernel_mode(regs)) 151 memset(&ti->cpu_context, 0, sizeof(struct cpu_context)); 152 /* if this thread is created for fork/vfork/clone, then we want to 153 * restore all the parent's context */ 154 /* in addition to the registers which will be restored by POP_STATE */ 155 else { 156 ti->cpu_context = *(struct cpu_context *)regs; 157 childregs->msr |= MSR_UMS; 158 } 159 160 /* FIXME STATE_SAVE_PT_OFFSET; */ 161 ti->cpu_context.r1 = (unsigned long)childregs; 162 /* we should consider the fact that childregs is a copy of the parent 163 * regs which were saved immediately after entering the kernel state 164 * before enabling VM. This MSR will be restored in switch_to and 165 * RETURN() and we want to have the right machine state there 166 * specifically this state must have INTs disabled before and enabled 167 * after performing rtbd 168 * compose the right MSR for RETURN(). It will work for switch_to also 169 * excepting for VM and UMS 170 * don't touch UMS , CARRY and cache bits 171 * right now MSR is a copy of parent one */ 172 childregs->msr |= MSR_BIP; 173 childregs->msr &= ~MSR_EIP; 174 childregs->msr |= MSR_IE; 175 childregs->msr &= ~MSR_VM; 176 childregs->msr |= MSR_VMS; 177 childregs->msr |= MSR_EE; /* exceptions will be enabled*/ 178 179 ti->cpu_context.msr = (childregs->msr|MSR_VM); 180 ti->cpu_context.msr &= ~MSR_UMS; /* switch_to to kernel mode */ 181 ti->cpu_context.msr &= ~MSR_IE; 182 #endif 183 ti->cpu_context.r15 = (unsigned long)ret_from_fork - 8; 184 185 /* 186 * r21 is the thread reg, r10 is 6th arg to clone 187 * which contains TLS area 188 */ 189 if (clone_flags & CLONE_SETTLS) 190 childregs->r21 = childregs->r10; 191 192 return 0; 193 } 194 195 #ifndef CONFIG_MMU 196 /* 197 * Return saved PC of a blocked thread. 198 */ 199 unsigned long thread_saved_pc(struct task_struct *tsk) 200 { 201 struct cpu_context *ctx = 202 &(((struct thread_info *)(tsk->stack))->cpu_context); 203 204 /* Check whether the thread is blocked in resume() */ 205 if (in_sched_functions(ctx->r15)) 206 return (unsigned long)ctx->r15; 207 else 208 return ctx->r14; 209 } 210 #endif 211 212 static void kernel_thread_helper(int (*fn)(void *), void *arg) 213 { 214 fn(arg); 215 do_exit(-1); 216 } 217 218 int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) 219 { 220 struct pt_regs regs; 221 222 memset(®s, 0, sizeof(regs)); 223 /* store them in non-volatile registers */ 224 regs.r5 = (unsigned long)fn; 225 regs.r6 = (unsigned long)arg; 226 local_save_flags(regs.msr); 227 regs.pc = (unsigned long)kernel_thread_helper; 228 regs.pt_mode = 1; 229 230 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, 231 ®s, 0, NULL, NULL); 232 } 233 EXPORT_SYMBOL_GPL(kernel_thread); 234 235 unsigned long get_wchan(struct task_struct *p) 236 { 237 /* TBD (used by procfs) */ 238 return 0; 239 } 240 241 /* Set up a thread for executing a new program */ 242 void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp) 243 { 244 regs->pc = pc; 245 regs->r1 = usp; 246 regs->pt_mode = 0; 247 #ifdef CONFIG_MMU 248 regs->msr |= MSR_UMS; 249 #endif 250 } 251 252 #ifdef CONFIG_MMU 253 #include <linux/elfcore.h> 254 /* 255 * Set up a thread for executing a new program 256 */ 257 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs) 258 { 259 return 0; /* MicroBlaze has no separate FPU registers */ 260 } 261 #endif /* CONFIG_MMU */ 262