1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/arch/m68k/kernel/process.c 4 * 5 * Copyright (C) 1995 Hamish Macdonald 6 * 7 * 68060 fixes by Jesper Skov 8 */ 9 10 /* 11 * This file handles the architecture-dependent parts of process handling.. 12 */ 13 14 #include <linux/errno.h> 15 #include <linux/module.h> 16 #include <linux/sched.h> 17 #include <linux/sched/debug.h> 18 #include <linux/sched/task.h> 19 #include <linux/sched/task_stack.h> 20 #include <linux/kernel.h> 21 #include <linux/mm.h> 22 #include <linux/slab.h> 23 #include <linux/fs.h> 24 #include <linux/smp.h> 25 #include <linux/stddef.h> 26 #include <linux/unistd.h> 27 #include <linux/ptrace.h> 28 #include <linux/user.h> 29 #include <linux/reboot.h> 30 #include <linux/init_task.h> 31 #include <linux/mqueue.h> 32 #include <linux/rcupdate.h> 33 #include <linux/syscalls.h> 34 #include <linux/uaccess.h> 35 36 #include <asm/traps.h> 37 #include <asm/machdep.h> 38 #include <asm/setup.h> 39 #include <asm/pgtable.h> 40 41 42 asmlinkage void ret_from_fork(void); 43 asmlinkage void ret_from_kernel_thread(void); 44 45 void arch_cpu_idle(void) 46 { 47 #if defined(MACH_ATARI_ONLY) 48 /* block out HSYNC on the atari (falcon) */ 49 __asm__("stop #0x2200" : : : "cc"); 50 #else 51 __asm__("stop #0x2000" : : : "cc"); 52 #endif 53 } 54 55 void machine_restart(char * __unused) 56 { 57 if (mach_reset) 58 mach_reset(); 59 for (;;); 60 } 61 62 void machine_halt(void) 63 { 64 if (mach_halt) 65 mach_halt(); 66 for (;;); 67 } 68 69 void machine_power_off(void) 70 { 71 if (mach_power_off) 72 mach_power_off(); 73 for (;;); 74 } 75 76 void (*pm_power_off)(void) = machine_power_off; 77 EXPORT_SYMBOL(pm_power_off); 78 79 void show_regs(struct pt_regs * regs) 80 { 81 pr_info("Format %02x Vector: %04x PC: %08lx Status: %04x %s\n", 82 regs->format, regs->vector, regs->pc, regs->sr, 83 print_tainted()); 84 pr_info("ORIG_D0: %08lx D0: %08lx A2: %08lx A1: %08lx\n", 85 regs->orig_d0, regs->d0, regs->a2, regs->a1); 86 pr_info("A0: %08lx D5: %08lx D4: %08lx\n", regs->a0, regs->d5, 87 regs->d4); 88 pr_info("D3: %08lx D2: %08lx D1: %08lx\n", regs->d3, regs->d2, 89 regs->d1); 90 if (!(regs->sr & PS_S)) 91 pr_info("USP: %08lx\n", rdusp()); 92 } 93 94 void flush_thread(void) 95 { 96 current->thread.fs = __USER_DS; 97 #ifdef CONFIG_FPU 98 if (!FPU_IS_EMU) { 99 unsigned long zero = 0; 100 asm volatile("frestore %0": :"m" (zero)); 101 } 102 #endif 103 } 104 105 /* 106 * Why not generic sys_clone, you ask? m68k passes all arguments on stack. 107 * And we need all registers saved, which means a bunch of stuff pushed 108 * on top of pt_regs, which means that sys_clone() arguments would be 109 * buried. We could, of course, copy them, but it's too costly for no 110 * good reason - generic clone() would have to copy them *again* for 111 * do_fork() anyway. So in this case it's actually better to pass pt_regs * 112 * and extract arguments for do_fork() from there. Eventually we might 113 * go for calling do_fork() directly from the wrapper, but only after we 114 * are finished with do_fork() prototype conversion. 115 */ 116 asmlinkage int m68k_clone(struct pt_regs *regs) 117 { 118 /* regs will be equal to current_pt_regs() */ 119 return do_fork(regs->d1, regs->d2, 0, 120 (int __user *)regs->d3, (int __user *)regs->d4); 121 } 122 123 /* 124 * Because extra registers are saved on the stack after the sys_clone3() 125 * arguments, this C wrapper extracts them from pt_regs * and then calls the 126 * generic sys_clone3() implementation. 127 */ 128 asmlinkage int m68k_clone3(struct pt_regs *regs) 129 { 130 return sys_clone3((struct clone_args __user *)regs->d1, regs->d2); 131 } 132 133 int copy_thread(unsigned long clone_flags, unsigned long usp, 134 unsigned long arg, struct task_struct *p) 135 { 136 struct fork_frame { 137 struct switch_stack sw; 138 struct pt_regs regs; 139 } *frame; 140 141 frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1; 142 143 p->thread.ksp = (unsigned long)frame; 144 p->thread.esp0 = (unsigned long)&frame->regs; 145 146 /* 147 * Must save the current SFC/DFC value, NOT the value when 148 * the parent was last descheduled - RGH 10-08-96 149 */ 150 p->thread.fs = get_fs().seg; 151 152 if (unlikely(p->flags & PF_KTHREAD)) { 153 /* kernel thread */ 154 memset(frame, 0, sizeof(struct fork_frame)); 155 frame->regs.sr = PS_S; 156 frame->sw.a3 = usp; /* function */ 157 frame->sw.d7 = arg; 158 frame->sw.retpc = (unsigned long)ret_from_kernel_thread; 159 p->thread.usp = 0; 160 return 0; 161 } 162 memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs), 163 sizeof(struct fork_frame)); 164 frame->regs.d0 = 0; 165 frame->sw.retpc = (unsigned long)ret_from_fork; 166 p->thread.usp = usp ?: rdusp(); 167 168 if (clone_flags & CLONE_SETTLS) 169 task_thread_info(p)->tp_value = frame->regs.d5; 170 171 #ifdef CONFIG_FPU 172 if (!FPU_IS_EMU) { 173 /* Copy the current fpu state */ 174 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory"); 175 176 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) { 177 if (CPU_IS_COLDFIRE) { 178 asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t" 179 "fmovel %/fpiar,%1\n\t" 180 "fmovel %/fpcr,%2\n\t" 181 "fmovel %/fpsr,%3" 182 : 183 : "m" (p->thread.fp[0]), 184 "m" (p->thread.fpcntl[0]), 185 "m" (p->thread.fpcntl[1]), 186 "m" (p->thread.fpcntl[2]) 187 : "memory"); 188 } else { 189 asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t" 190 "fmoveml %/fpiar/%/fpcr/%/fpsr,%1" 191 : 192 : "m" (p->thread.fp[0]), 193 "m" (p->thread.fpcntl[0]) 194 : "memory"); 195 } 196 } 197 198 /* Restore the state in case the fpu was busy */ 199 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0])); 200 } 201 #endif /* CONFIG_FPU */ 202 203 return 0; 204 } 205 206 /* Fill in the fpu structure for a core dump. */ 207 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu) 208 { 209 if (FPU_IS_EMU) { 210 int i; 211 212 memcpy(fpu->fpcntl, current->thread.fpcntl, 12); 213 memcpy(fpu->fpregs, current->thread.fp, 96); 214 /* Convert internal fpu reg representation 215 * into long double format 216 */ 217 for (i = 0; i < 24; i += 3) 218 fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) | 219 ((fpu->fpregs[i] & 0x0000ffff) << 16); 220 return 1; 221 } 222 223 if (IS_ENABLED(CONFIG_FPU)) { 224 char fpustate[216]; 225 226 /* First dump the fpu context to avoid protocol violation. */ 227 asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory"); 228 if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2]) 229 return 0; 230 231 if (CPU_IS_COLDFIRE) { 232 asm volatile ("fmovel %/fpiar,%0\n\t" 233 "fmovel %/fpcr,%1\n\t" 234 "fmovel %/fpsr,%2\n\t" 235 "fmovemd %/fp0-%/fp7,%3" 236 : 237 : "m" (fpu->fpcntl[0]), 238 "m" (fpu->fpcntl[1]), 239 "m" (fpu->fpcntl[2]), 240 "m" (fpu->fpregs[0]) 241 : "memory"); 242 } else { 243 asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0" 244 : 245 : "m" (fpu->fpcntl[0]) 246 : "memory"); 247 asm volatile ("fmovemx %/fp0-%/fp7,%0" 248 : 249 : "m" (fpu->fpregs[0]) 250 : "memory"); 251 } 252 } 253 254 return 1; 255 } 256 EXPORT_SYMBOL(dump_fpu); 257 258 unsigned long get_wchan(struct task_struct *p) 259 { 260 unsigned long fp, pc; 261 unsigned long stack_page; 262 int count = 0; 263 if (!p || p == current || p->state == TASK_RUNNING) 264 return 0; 265 266 stack_page = (unsigned long)task_stack_page(p); 267 fp = ((struct switch_stack *)p->thread.ksp)->a6; 268 do { 269 if (fp < stack_page+sizeof(struct thread_info) || 270 fp >= 8184+stack_page) 271 return 0; 272 pc = ((unsigned long *)fp)[1]; 273 if (!in_sched_functions(pc)) 274 return pc; 275 fp = *(unsigned long *) fp; 276 } while (count++ < 16); 277 return 0; 278 } 279