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 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 do_kernel_power_off(); 72 for (;;); 73 } 74 75 void (*pm_power_off)(void); 76 EXPORT_SYMBOL(pm_power_off); 77 78 void show_regs(struct pt_regs * regs) 79 { 80 pr_info("Format %02x Vector: %04x PC: %08lx Status: %04x %s\n", 81 regs->format, regs->vector, regs->pc, regs->sr, 82 print_tainted()); 83 pr_info("ORIG_D0: %08lx D0: %08lx A2: %08lx A1: %08lx\n", 84 regs->orig_d0, regs->d0, regs->a2, regs->a1); 85 pr_info("A0: %08lx D5: %08lx D4: %08lx\n", regs->a0, regs->d5, 86 regs->d4); 87 pr_info("D3: %08lx D2: %08lx D1: %08lx\n", regs->d3, regs->d2, 88 regs->d1); 89 if (!(regs->sr & PS_S)) 90 pr_info("USP: %08lx\n", rdusp()); 91 } 92 93 void flush_thread(void) 94 { 95 current->thread.fc = USER_DATA; 96 #ifdef CONFIG_FPU 97 if (!FPU_IS_EMU) { 98 unsigned long zero = 0; 99 asm volatile("frestore %0": :"m" (zero)); 100 } 101 #endif 102 } 103 104 /* 105 * Why not generic sys_clone, you ask? m68k passes all arguments on stack. 106 * And we need all registers saved, which means a bunch of stuff pushed 107 * on top of pt_regs, which means that sys_clone() arguments would be 108 * buried. We could, of course, copy them, but it's too costly for no 109 * good reason - generic clone() would have to copy them *again* for 110 * kernel_clone() anyway. So in this case it's actually better to pass pt_regs * 111 * and extract arguments for kernel_clone() from there. Eventually we might 112 * go for calling kernel_clone() directly from the wrapper, but only after we 113 * are finished with kernel_clone() prototype conversion. 114 */ 115 asmlinkage int m68k_clone(struct pt_regs *regs) 116 { 117 /* regs will be equal to current_pt_regs() */ 118 struct kernel_clone_args args = { 119 .flags = (u32)(regs->d1) & ~CSIGNAL, 120 .pidfd = (int __user *)regs->d3, 121 .child_tid = (int __user *)regs->d4, 122 .parent_tid = (int __user *)regs->d3, 123 .exit_signal = regs->d1 & CSIGNAL, 124 .stack = regs->d2, 125 .tls = regs->d5, 126 }; 127 128 return kernel_clone(&args); 129 } 130 131 /* 132 * Because extra registers are saved on the stack after the sys_clone3() 133 * arguments, this C wrapper extracts them from pt_regs * and then calls the 134 * generic sys_clone3() implementation. 135 */ 136 asmlinkage int m68k_clone3(struct pt_regs *regs) 137 { 138 return sys_clone3((struct clone_args __user *)regs->d1, regs->d2); 139 } 140 141 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) 142 { 143 unsigned long clone_flags = args->flags; 144 unsigned long usp = args->stack; 145 unsigned long tls = args->tls; 146 struct fork_frame { 147 struct switch_stack sw; 148 struct pt_regs regs; 149 } *frame; 150 151 frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1; 152 153 p->thread.ksp = (unsigned long)frame; 154 p->thread.esp0 = (unsigned long)&frame->regs; 155 156 /* 157 * Must save the current SFC/DFC value, NOT the value when 158 * the parent was last descheduled - RGH 10-08-96 159 */ 160 p->thread.fc = USER_DATA; 161 162 if (unlikely(args->fn)) { 163 /* kernel thread */ 164 memset(frame, 0, sizeof(struct fork_frame)); 165 frame->regs.sr = PS_S; 166 frame->sw.a3 = (unsigned long)args->fn; 167 frame->sw.d7 = (unsigned long)args->fn_arg; 168 frame->sw.retpc = (unsigned long)ret_from_kernel_thread; 169 p->thread.usp = 0; 170 return 0; 171 } 172 memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs), 173 sizeof(struct fork_frame)); 174 frame->regs.d0 = 0; 175 frame->sw.retpc = (unsigned long)ret_from_fork; 176 p->thread.usp = usp ?: rdusp(); 177 178 if (clone_flags & CLONE_SETTLS) 179 task_thread_info(p)->tp_value = tls; 180 181 #ifdef CONFIG_FPU 182 if (!FPU_IS_EMU) { 183 /* Copy the current fpu state */ 184 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory"); 185 186 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) { 187 if (CPU_IS_COLDFIRE) { 188 asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t" 189 "fmovel %/fpiar,%1\n\t" 190 "fmovel %/fpcr,%2\n\t" 191 "fmovel %/fpsr,%3" 192 : 193 : "m" (p->thread.fp[0]), 194 "m" (p->thread.fpcntl[0]), 195 "m" (p->thread.fpcntl[1]), 196 "m" (p->thread.fpcntl[2]) 197 : "memory"); 198 } else { 199 asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t" 200 "fmoveml %/fpiar/%/fpcr/%/fpsr,%1" 201 : 202 : "m" (p->thread.fp[0]), 203 "m" (p->thread.fpcntl[0]) 204 : "memory"); 205 } 206 } 207 208 /* Restore the state in case the fpu was busy */ 209 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0])); 210 } 211 #endif /* CONFIG_FPU */ 212 213 return 0; 214 } 215 216 /* Fill in the fpu structure for a core dump. */ 217 int elf_core_copy_task_fpregs(struct task_struct *t, elf_fpregset_t *fpu) 218 { 219 if (FPU_IS_EMU) { 220 int i; 221 222 memcpy(fpu->fpcntl, current->thread.fpcntl, 12); 223 memcpy(fpu->fpregs, current->thread.fp, 96); 224 /* Convert internal fpu reg representation 225 * into long double format 226 */ 227 for (i = 0; i < 24; i += 3) 228 fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) | 229 ((fpu->fpregs[i] & 0x0000ffff) << 16); 230 return 1; 231 } 232 233 if (IS_ENABLED(CONFIG_FPU)) { 234 char fpustate[216]; 235 236 /* First dump the fpu context to avoid protocol violation. */ 237 asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory"); 238 if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2]) 239 return 0; 240 241 if (CPU_IS_COLDFIRE) { 242 asm volatile ("fmovel %/fpiar,%0\n\t" 243 "fmovel %/fpcr,%1\n\t" 244 "fmovel %/fpsr,%2\n\t" 245 "fmovemd %/fp0-%/fp7,%3" 246 : 247 : "m" (fpu->fpcntl[0]), 248 "m" (fpu->fpcntl[1]), 249 "m" (fpu->fpcntl[2]), 250 "m" (fpu->fpregs[0]) 251 : "memory"); 252 } else { 253 asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0" 254 : 255 : "m" (fpu->fpcntl[0]) 256 : "memory"); 257 asm volatile ("fmovemx %/fp0-%/fp7,%0" 258 : 259 : "m" (fpu->fpregs[0]) 260 : "memory"); 261 } 262 } 263 264 return 1; 265 } 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