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 40 41 asmlinkage void ret_from_fork(void); 42 asmlinkage void ret_from_kernel_thread(void); 43 44 void arch_cpu_idle(void) 45 { 46 #if defined(MACH_ATARI_ONLY) 47 /* block out HSYNC on the atari (falcon) */ 48 __asm__("stop #0x2200" : : : "cc"); 49 #else 50 __asm__("stop #0x2000" : : : "cc"); 51 #endif 52 } 53 54 void machine_restart(char * __unused) 55 { 56 if (mach_reset) 57 mach_reset(); 58 for (;;); 59 } 60 61 void machine_halt(void) 62 { 63 if (mach_halt) 64 mach_halt(); 65 for (;;); 66 } 67 68 void machine_power_off(void) 69 { 70 do_kernel_power_off(); 71 for (;;); 72 } 73 74 void (*pm_power_off)(void); 75 EXPORT_SYMBOL(pm_power_off); 76 77 void show_regs(struct pt_regs * regs) 78 { 79 pr_info("Format %02x Vector: %04x PC: %08lx Status: %04x %s\n", 80 regs->format, regs->vector, regs->pc, regs->sr, 81 print_tainted()); 82 pr_info("ORIG_D0: %08lx D0: %08lx A2: %08lx A1: %08lx\n", 83 regs->orig_d0, regs->d0, regs->a2, regs->a1); 84 pr_info("A0: %08lx D5: %08lx D4: %08lx\n", regs->a0, regs->d5, 85 regs->d4); 86 pr_info("D3: %08lx D2: %08lx D1: %08lx\n", regs->d3, regs->d2, 87 regs->d1); 88 if (!(regs->sr & PS_S)) 89 pr_info("USP: %08lx\n", rdusp()); 90 } 91 92 void flush_thread(void) 93 { 94 current->thread.fc = USER_DATA; 95 #ifdef CONFIG_FPU 96 if (!FPU_IS_EMU) { 97 unsigned long zero = 0; 98 asm volatile("frestore %0": :"m" (zero)); 99 } 100 #endif 101 } 102 103 /* 104 * Why not generic sys_clone, you ask? m68k passes all arguments on stack. 105 * And we need all registers saved, which means a bunch of stuff pushed 106 * on top of pt_regs, which means that sys_clone() arguments would be 107 * buried. We could, of course, copy them, but it's too costly for no 108 * good reason - generic clone() would have to copy them *again* for 109 * kernel_clone() anyway. So in this case it's actually better to pass pt_regs * 110 * and extract arguments for kernel_clone() from there. Eventually we might 111 * go for calling kernel_clone() directly from the wrapper, but only after we 112 * are finished with kernel_clone() prototype conversion. 113 */ 114 asmlinkage int m68k_clone(struct pt_regs *regs) 115 { 116 /* regs will be equal to current_pt_regs() */ 117 struct kernel_clone_args args = { 118 .flags = regs->d1 & ~CSIGNAL, 119 .pidfd = (int __user *)regs->d3, 120 .child_tid = (int __user *)regs->d4, 121 .parent_tid = (int __user *)regs->d3, 122 .exit_signal = regs->d1 & CSIGNAL, 123 .stack = regs->d2, 124 .tls = regs->d5, 125 }; 126 127 return kernel_clone(&args); 128 } 129 130 /* 131 * Because extra registers are saved on the stack after the sys_clone3() 132 * arguments, this C wrapper extracts them from pt_regs * and then calls the 133 * generic sys_clone3() implementation. 134 */ 135 asmlinkage int m68k_clone3(struct pt_regs *regs) 136 { 137 return sys_clone3((struct clone_args __user *)regs->d1, regs->d2); 138 } 139 140 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) 141 { 142 unsigned long clone_flags = args->flags; 143 unsigned long usp = args->stack; 144 unsigned long tls = args->tls; 145 struct fork_frame { 146 struct switch_stack sw; 147 struct pt_regs regs; 148 } *frame; 149 150 frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1; 151 152 p->thread.ksp = (unsigned long)frame; 153 p->thread.esp0 = (unsigned long)&frame->regs; 154 155 /* 156 * Must save the current SFC/DFC value, NOT the value when 157 * the parent was last descheduled - RGH 10-08-96 158 */ 159 p->thread.fc = USER_DATA; 160 161 if (unlikely(args->fn)) { 162 /* kernel thread */ 163 memset(frame, 0, sizeof(struct fork_frame)); 164 frame->regs.sr = PS_S; 165 frame->sw.a3 = (unsigned long)args->fn; 166 frame->sw.d7 = (unsigned long)args->fn_arg; 167 frame->sw.retpc = (unsigned long)ret_from_kernel_thread; 168 p->thread.usp = 0; 169 return 0; 170 } 171 memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs), 172 sizeof(struct fork_frame)); 173 frame->regs.d0 = 0; 174 frame->sw.retpc = (unsigned long)ret_from_fork; 175 p->thread.usp = usp ?: rdusp(); 176 177 if (clone_flags & CLONE_SETTLS) 178 task_thread_info(p)->tp_value = tls; 179 180 #ifdef CONFIG_FPU 181 if (!FPU_IS_EMU) { 182 /* Copy the current fpu state */ 183 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory"); 184 185 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) { 186 if (CPU_IS_COLDFIRE) { 187 asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t" 188 "fmovel %/fpiar,%1\n\t" 189 "fmovel %/fpcr,%2\n\t" 190 "fmovel %/fpsr,%3" 191 : 192 : "m" (p->thread.fp[0]), 193 "m" (p->thread.fpcntl[0]), 194 "m" (p->thread.fpcntl[1]), 195 "m" (p->thread.fpcntl[2]) 196 : "memory"); 197 } else { 198 asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t" 199 "fmoveml %/fpiar/%/fpcr/%/fpsr,%1" 200 : 201 : "m" (p->thread.fp[0]), 202 "m" (p->thread.fpcntl[0]) 203 : "memory"); 204 } 205 } 206 207 /* Restore the state in case the fpu was busy */ 208 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0])); 209 } 210 #endif /* CONFIG_FPU */ 211 212 return 0; 213 } 214 215 /* Fill in the fpu structure for a core dump. */ 216 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu) 217 { 218 if (FPU_IS_EMU) { 219 int i; 220 221 memcpy(fpu->fpcntl, current->thread.fpcntl, 12); 222 memcpy(fpu->fpregs, current->thread.fp, 96); 223 /* Convert internal fpu reg representation 224 * into long double format 225 */ 226 for (i = 0; i < 24; i += 3) 227 fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) | 228 ((fpu->fpregs[i] & 0x0000ffff) << 16); 229 return 1; 230 } 231 232 if (IS_ENABLED(CONFIG_FPU)) { 233 char fpustate[216]; 234 235 /* First dump the fpu context to avoid protocol violation. */ 236 asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory"); 237 if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2]) 238 return 0; 239 240 if (CPU_IS_COLDFIRE) { 241 asm volatile ("fmovel %/fpiar,%0\n\t" 242 "fmovel %/fpcr,%1\n\t" 243 "fmovel %/fpsr,%2\n\t" 244 "fmovemd %/fp0-%/fp7,%3" 245 : 246 : "m" (fpu->fpcntl[0]), 247 "m" (fpu->fpcntl[1]), 248 "m" (fpu->fpcntl[2]), 249 "m" (fpu->fpregs[0]) 250 : "memory"); 251 } else { 252 asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0" 253 : 254 : "m" (fpu->fpcntl[0]) 255 : "memory"); 256 asm volatile ("fmovemx %/fp0-%/fp7,%0" 257 : 258 : "m" (fpu->fpregs[0]) 259 : "memory"); 260 } 261 } 262 263 return 1; 264 } 265 EXPORT_SYMBOL(dump_fpu); 266 267 unsigned long __get_wchan(struct task_struct *p) 268 { 269 unsigned long fp, pc; 270 unsigned long stack_page; 271 int count = 0; 272 273 stack_page = (unsigned long)task_stack_page(p); 274 fp = ((struct switch_stack *)p->thread.ksp)->a6; 275 do { 276 if (fp < stack_page+sizeof(struct thread_info) || 277 fp >= 8184+stack_page) 278 return 0; 279 pc = ((unsigned long *)fp)[1]; 280 if (!in_sched_functions(pc)) 281 return pc; 282 fp = *(unsigned long *) fp; 283 } while (count++ < 16); 284 return 0; 285 } 286