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 #include <linux/elfcore.h> 36 37 #include <asm/traps.h> 38 #include <asm/machdep.h> 39 #include <asm/setup.h> 40 41 #include "process.h" 42 43 asmlinkage void ret_from_fork(void); 44 asmlinkage void ret_from_kernel_thread(void); 45 46 void arch_cpu_idle(void) 47 { 48 #if defined(MACH_ATARI_ONLY) 49 /* block out HSYNC on the atari (falcon) */ 50 __asm__("stop #0x2200" : : : "cc"); 51 #else 52 __asm__("stop #0x2000" : : : "cc"); 53 #endif 54 } 55 56 void machine_restart(char * __unused) 57 { 58 if (mach_reset) 59 mach_reset(); 60 for (;;); 61 } 62 63 void machine_halt(void) 64 { 65 if (mach_halt) 66 mach_halt(); 67 for (;;); 68 } 69 70 void machine_power_off(void) 71 { 72 do_kernel_power_off(); 73 for (;;); 74 } 75 76 void (*pm_power_off)(void); 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.fc = USER_DATA; 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 * kernel_clone() anyway. So in this case it's actually better to pass pt_regs * 112 * and extract arguments for kernel_clone() from there. Eventually we might 113 * go for calling kernel_clone() directly from the wrapper, but only after we 114 * are finished with kernel_clone() prototype conversion. 115 */ 116 asmlinkage int m68k_clone(struct pt_regs *regs) 117 { 118 /* regs will be equal to current_pt_regs() */ 119 struct kernel_clone_args args = { 120 .flags = (u32)(regs->d1) & ~CSIGNAL, 121 .pidfd = (int __user *)regs->d3, 122 .child_tid = (int __user *)regs->d4, 123 .parent_tid = (int __user *)regs->d3, 124 .exit_signal = regs->d1 & CSIGNAL, 125 .stack = regs->d2, 126 .tls = regs->d5, 127 }; 128 129 return kernel_clone(&args); 130 } 131 132 /* 133 * Because extra registers are saved on the stack after the sys_clone3() 134 * arguments, this C wrapper extracts them from pt_regs * and then calls the 135 * generic sys_clone3() implementation. 136 */ 137 asmlinkage int m68k_clone3(struct pt_regs *regs) 138 { 139 return sys_clone3((struct clone_args __user *)regs->d1, regs->d2); 140 } 141 142 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) 143 { 144 unsigned long clone_flags = args->flags; 145 unsigned long usp = args->stack; 146 unsigned long tls = args->tls; 147 struct fork_frame { 148 struct switch_stack sw; 149 struct pt_regs regs; 150 } *frame; 151 152 frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1; 153 154 p->thread.ksp = (unsigned long)frame; 155 p->thread.esp0 = (unsigned long)&frame->regs; 156 157 /* 158 * Must save the current SFC/DFC value, NOT the value when 159 * the parent was last descheduled - RGH 10-08-96 160 */ 161 p->thread.fc = USER_DATA; 162 163 if (unlikely(args->fn)) { 164 /* kernel thread */ 165 memset(frame, 0, sizeof(struct fork_frame)); 166 frame->regs.sr = PS_S; 167 frame->sw.a3 = (unsigned long)args->fn; 168 frame->sw.d7 = (unsigned long)args->fn_arg; 169 frame->sw.retpc = (unsigned long)ret_from_kernel_thread; 170 p->thread.usp = 0; 171 return 0; 172 } 173 memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs), 174 sizeof(struct fork_frame)); 175 frame->regs.d0 = 0; 176 frame->sw.retpc = (unsigned long)ret_from_fork; 177 p->thread.usp = usp ?: rdusp(); 178 179 if (clone_flags & CLONE_SETTLS) 180 task_thread_info(p)->tp_value = tls; 181 182 #ifdef CONFIG_FPU 183 if (!FPU_IS_EMU) { 184 /* Copy the current fpu state */ 185 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory"); 186 187 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) { 188 if (CPU_IS_COLDFIRE) { 189 asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t" 190 "fmovel %/fpiar,%1\n\t" 191 "fmovel %/fpcr,%2\n\t" 192 "fmovel %/fpsr,%3" 193 : 194 : "m" (p->thread.fp[0]), 195 "m" (p->thread.fpcntl[0]), 196 "m" (p->thread.fpcntl[1]), 197 "m" (p->thread.fpcntl[2]) 198 : "memory"); 199 } else { 200 asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t" 201 "fmoveml %/fpiar/%/fpcr/%/fpsr,%1" 202 : 203 : "m" (p->thread.fp[0]), 204 "m" (p->thread.fpcntl[0]) 205 : "memory"); 206 } 207 } 208 209 /* Restore the state in case the fpu was busy */ 210 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0])); 211 } 212 #endif /* CONFIG_FPU */ 213 214 return 0; 215 } 216 217 /* Fill in the fpu structure for a core dump. */ 218 int elf_core_copy_task_fpregs(struct task_struct *t, elf_fpregset_t *fpu) 219 { 220 if (FPU_IS_EMU) { 221 int i; 222 223 memcpy(fpu->fpcntl, current->thread.fpcntl, 12); 224 memcpy(fpu->fpregs, current->thread.fp, 96); 225 /* Convert internal fpu reg representation 226 * into long double format 227 */ 228 for (i = 0; i < 24; i += 3) 229 fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) | 230 ((fpu->fpregs[i] & 0x0000ffff) << 16); 231 return 1; 232 } 233 234 if (IS_ENABLED(CONFIG_FPU)) { 235 char fpustate[216]; 236 237 /* First dump the fpu context to avoid protocol violation. */ 238 asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory"); 239 if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2]) 240 return 0; 241 242 if (CPU_IS_COLDFIRE) { 243 asm volatile ("fmovel %/fpiar,%0\n\t" 244 "fmovel %/fpcr,%1\n\t" 245 "fmovel %/fpsr,%2\n\t" 246 "fmovemd %/fp0-%/fp7,%3" 247 : 248 : "m" (fpu->fpcntl[0]), 249 "m" (fpu->fpcntl[1]), 250 "m" (fpu->fpcntl[2]), 251 "m" (fpu->fpregs[0]) 252 : "memory"); 253 } else { 254 asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0" 255 : 256 : "m" (fpu->fpcntl[0]) 257 : "memory"); 258 asm volatile ("fmovemx %/fp0-%/fp7,%0" 259 : 260 : "m" (fpu->fpregs[0]) 261 : "memory"); 262 } 263 } 264 265 return 1; 266 } 267 268 unsigned long __get_wchan(struct task_struct *p) 269 { 270 unsigned long fp, pc; 271 unsigned long stack_page; 272 int count = 0; 273 274 stack_page = (unsigned long)task_stack_page(p); 275 fp = ((struct switch_stack *)p->thread.ksp)->a6; 276 do { 277 if (fp < stack_page+sizeof(struct thread_info) || 278 fp >= 8184+stack_page) 279 return 0; 280 pc = ((unsigned long *)fp)[1]; 281 if (!in_sched_functions(pc)) 282 return pc; 283 fp = *(unsigned long *) fp; 284 } while (count++ < 16); 285 return 0; 286 } 287