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 21 void 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 44 void (*pm_idle)(void); 45 void (*pm_power_off)(void) = NULL; 46 EXPORT_SYMBOL(pm_power_off); 47 48 static int hlt_counter = 1; 49 50 void disable_hlt(void) 51 { 52 hlt_counter++; 53 } 54 EXPORT_SYMBOL(disable_hlt); 55 56 void enable_hlt(void) 57 { 58 hlt_counter--; 59 } 60 EXPORT_SYMBOL(enable_hlt); 61 62 static int __init nohlt_setup(char *__unused) 63 { 64 hlt_counter = 1; 65 return 1; 66 } 67 __setup("nohlt", nohlt_setup); 68 69 static int __init hlt_setup(char *__unused) 70 { 71 hlt_counter = 0; 72 return 1; 73 } 74 __setup("hlt", hlt_setup); 75 76 void 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 95 void 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 } 117 118 void flush_thread(void) 119 { 120 } 121 122 int 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 - STATE_SAVE_ARG_SPACE; 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 */ 195 unsigned 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 207 208 static void kernel_thread_helper(int (*fn)(void *), void *arg) 209 { 210 fn(arg); 211 do_exit(-1); 212 } 213 214 int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) 215 { 216 struct pt_regs regs; 217 218 memset(®s, 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 ®s, 0, NULL, NULL); 228 } 229 EXPORT_SYMBOL_GPL(kernel_thread); 230 231 unsigned 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 */ 238 void 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 */ 254 int 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