1 // SPDX-License-Identifier: GPL-2.0 2 /* linux/arch/sparc/kernel/process.c 3 * 4 * Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net) 5 * Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be) 6 */ 7 8 /* 9 * This file handles the architecture-dependent parts of process handling.. 10 */ 11 12 #include <stdarg.h> 13 14 #include <linux/elfcore.h> 15 #include <linux/errno.h> 16 #include <linux/module.h> 17 #include <linux/sched.h> 18 #include <linux/sched/debug.h> 19 #include <linux/sched/task.h> 20 #include <linux/sched/task_stack.h> 21 #include <linux/kernel.h> 22 #include <linux/mm.h> 23 #include <linux/stddef.h> 24 #include <linux/ptrace.h> 25 #include <linux/user.h> 26 #include <linux/smp.h> 27 #include <linux/reboot.h> 28 #include <linux/delay.h> 29 #include <linux/pm.h> 30 #include <linux/slab.h> 31 #include <linux/cpu.h> 32 33 #include <asm/auxio.h> 34 #include <asm/oplib.h> 35 #include <linux/uaccess.h> 36 #include <asm/page.h> 37 #include <asm/delay.h> 38 #include <asm/processor.h> 39 #include <asm/psr.h> 40 #include <asm/elf.h> 41 #include <asm/prom.h> 42 #include <asm/unistd.h> 43 #include <asm/setup.h> 44 45 #include "kernel.h" 46 47 /* 48 * Power management idle function 49 * Set in pm platform drivers (apc.c and pmc.c) 50 */ 51 void (*sparc_idle)(void); 52 53 /* 54 * Power-off handler instantiation for pm.h compliance 55 * This is done via auxio, but could be used as a fallback 56 * handler when auxio is not present-- unused for now... 57 */ 58 void (*pm_power_off)(void) = machine_power_off; 59 EXPORT_SYMBOL(pm_power_off); 60 61 /* 62 * sysctl - toggle power-off restriction for serial console 63 * systems in machine_power_off() 64 */ 65 int scons_pwroff = 1; 66 67 extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *); 68 69 struct task_struct *last_task_used_math = NULL; 70 struct thread_info *current_set[NR_CPUS]; 71 72 /* Idle loop support. */ 73 void arch_cpu_idle(void) 74 { 75 if (sparc_idle) 76 (*sparc_idle)(); 77 raw_local_irq_enable(); 78 } 79 80 /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */ 81 void machine_halt(void) 82 { 83 local_irq_enable(); 84 mdelay(8); 85 local_irq_disable(); 86 prom_halt(); 87 panic("Halt failed!"); 88 } 89 90 void machine_restart(char * cmd) 91 { 92 char *p; 93 94 local_irq_enable(); 95 mdelay(8); 96 local_irq_disable(); 97 98 p = strchr (reboot_command, '\n'); 99 if (p) *p = 0; 100 if (cmd) 101 prom_reboot(cmd); 102 if (*reboot_command) 103 prom_reboot(reboot_command); 104 prom_feval ("reset"); 105 panic("Reboot failed!"); 106 } 107 108 void machine_power_off(void) 109 { 110 if (auxio_power_register && 111 (!of_node_is_type(of_console_device, "serial") || scons_pwroff)) { 112 u8 power_register = sbus_readb(auxio_power_register); 113 power_register |= AUXIO_POWER_OFF; 114 sbus_writeb(power_register, auxio_power_register); 115 } 116 117 machine_halt(); 118 } 119 120 void show_regs(struct pt_regs *r) 121 { 122 struct reg_window32 *rw = (struct reg_window32 *) r->u_regs[14]; 123 124 show_regs_print_info(KERN_DEFAULT); 125 126 printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx %s\n", 127 r->psr, r->pc, r->npc, r->y, print_tainted()); 128 printk("PC: <%pS>\n", (void *) r->pc); 129 printk("%%G: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n", 130 r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3], 131 r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]); 132 printk("%%O: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n", 133 r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11], 134 r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]); 135 printk("RPC: <%pS>\n", (void *) r->u_regs[15]); 136 137 printk("%%L: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n", 138 rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3], 139 rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]); 140 printk("%%I: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n", 141 rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3], 142 rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]); 143 } 144 145 /* 146 * The show_stack() is external API which we do not use ourselves. 147 * The oops is printed in die_if_kernel. 148 */ 149 void show_stack(struct task_struct *tsk, unsigned long *_ksp, const char *loglvl) 150 { 151 unsigned long pc, fp; 152 unsigned long task_base; 153 struct reg_window32 *rw; 154 int count = 0; 155 156 if (!tsk) 157 tsk = current; 158 159 if (tsk == current && !_ksp) 160 __asm__ __volatile__("mov %%fp, %0" : "=r" (_ksp)); 161 162 task_base = (unsigned long) task_stack_page(tsk); 163 fp = (unsigned long) _ksp; 164 do { 165 /* Bogus frame pointer? */ 166 if (fp < (task_base + sizeof(struct thread_info)) || 167 fp >= (task_base + (PAGE_SIZE << 1))) 168 break; 169 rw = (struct reg_window32 *) fp; 170 pc = rw->ins[7]; 171 printk("%s[%08lx : ", loglvl, pc); 172 printk("%s%pS ] ", loglvl, (void *) pc); 173 fp = rw->ins[6]; 174 } while (++count < 16); 175 printk("%s\n", loglvl); 176 } 177 178 /* 179 * Free current thread data structures etc.. 180 */ 181 void exit_thread(struct task_struct *tsk) 182 { 183 #ifndef CONFIG_SMP 184 if (last_task_used_math == tsk) { 185 #else 186 if (test_tsk_thread_flag(tsk, TIF_USEDFPU)) { 187 #endif 188 /* Keep process from leaving FPU in a bogon state. */ 189 put_psr(get_psr() | PSR_EF); 190 fpsave(&tsk->thread.float_regs[0], &tsk->thread.fsr, 191 &tsk->thread.fpqueue[0], &tsk->thread.fpqdepth); 192 #ifndef CONFIG_SMP 193 last_task_used_math = NULL; 194 #else 195 clear_ti_thread_flag(task_thread_info(tsk), TIF_USEDFPU); 196 #endif 197 } 198 } 199 200 void flush_thread(void) 201 { 202 current_thread_info()->w_saved = 0; 203 204 #ifndef CONFIG_SMP 205 if(last_task_used_math == current) { 206 #else 207 if (test_thread_flag(TIF_USEDFPU)) { 208 #endif 209 /* Clean the fpu. */ 210 put_psr(get_psr() | PSR_EF); 211 fpsave(¤t->thread.float_regs[0], ¤t->thread.fsr, 212 ¤t->thread.fpqueue[0], ¤t->thread.fpqdepth); 213 #ifndef CONFIG_SMP 214 last_task_used_math = NULL; 215 #else 216 clear_thread_flag(TIF_USEDFPU); 217 #endif 218 } 219 } 220 221 static inline struct sparc_stackf __user * 222 clone_stackframe(struct sparc_stackf __user *dst, 223 struct sparc_stackf __user *src) 224 { 225 unsigned long size, fp; 226 struct sparc_stackf *tmp; 227 struct sparc_stackf __user *sp; 228 229 if (get_user(tmp, &src->fp)) 230 return NULL; 231 232 fp = (unsigned long) tmp; 233 size = (fp - ((unsigned long) src)); 234 fp = (unsigned long) dst; 235 sp = (struct sparc_stackf __user *)(fp - size); 236 237 /* do_fork() grabs the parent semaphore, we must release it 238 * temporarily so we can build the child clone stack frame 239 * without deadlocking. 240 */ 241 if (__copy_user(sp, src, size)) 242 sp = NULL; 243 else if (put_user(fp, &sp->fp)) 244 sp = NULL; 245 246 return sp; 247 } 248 249 /* Copy a Sparc thread. The fork() return value conventions 250 * under SunOS are nothing short of bletcherous: 251 * Parent --> %o0 == childs pid, %o1 == 0 252 * Child --> %o0 == parents pid, %o1 == 1 253 * 254 * NOTE: We have a separate fork kpsr/kwim because 255 * the parent could change these values between 256 * sys_fork invocation and when we reach here 257 * if the parent should sleep while trying to 258 * allocate the task_struct and kernel stack in 259 * do_fork(). 260 * XXX See comment above sys_vfork in sparc64. todo. 261 */ 262 extern void ret_from_fork(void); 263 extern void ret_from_kernel_thread(void); 264 265 int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg, 266 struct task_struct *p, unsigned long tls) 267 { 268 struct thread_info *ti = task_thread_info(p); 269 struct pt_regs *childregs, *regs = current_pt_regs(); 270 char *new_stack; 271 272 #ifndef CONFIG_SMP 273 if(last_task_used_math == current) { 274 #else 275 if (test_thread_flag(TIF_USEDFPU)) { 276 #endif 277 put_psr(get_psr() | PSR_EF); 278 fpsave(&p->thread.float_regs[0], &p->thread.fsr, 279 &p->thread.fpqueue[0], &p->thread.fpqdepth); 280 } 281 282 /* 283 * p->thread_info new_stack childregs stack bottom 284 * ! ! ! ! 285 * V V (stk.fr.) V (pt_regs) V 286 * +----- - - - - - ------+===========+=============+ 287 */ 288 new_stack = task_stack_page(p) + THREAD_SIZE; 289 new_stack -= STACKFRAME_SZ + TRACEREG_SZ; 290 childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ); 291 292 /* 293 * A new process must start with interrupts disabled, see schedule_tail() 294 * and finish_task_switch(). (If we do not do it and if a timer interrupt 295 * hits before we unlock and attempts to take the rq->lock, we deadlock.) 296 * 297 * Thus, kpsr |= PSR_PIL. 298 */ 299 ti->ksp = (unsigned long) new_stack; 300 p->thread.kregs = childregs; 301 302 if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) { 303 extern int nwindows; 304 unsigned long psr; 305 memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ); 306 p->thread.current_ds = KERNEL_DS; 307 ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8); 308 childregs->u_regs[UREG_G1] = sp; /* function */ 309 childregs->u_regs[UREG_G2] = arg; 310 psr = childregs->psr = get_psr(); 311 ti->kpsr = psr | PSR_PIL; 312 ti->kwim = 1 << (((psr & PSR_CWP) + 1) % nwindows); 313 return 0; 314 } 315 memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ); 316 childregs->u_regs[UREG_FP] = sp; 317 p->thread.current_ds = USER_DS; 318 ti->kpc = (((unsigned long) ret_from_fork) - 0x8); 319 ti->kpsr = current->thread.fork_kpsr | PSR_PIL; 320 ti->kwim = current->thread.fork_kwim; 321 322 if (sp != regs->u_regs[UREG_FP]) { 323 struct sparc_stackf __user *childstack; 324 struct sparc_stackf __user *parentstack; 325 326 /* 327 * This is a clone() call with supplied user stack. 328 * Set some valid stack frames to give to the child. 329 */ 330 childstack = (struct sparc_stackf __user *) 331 (sp & ~0xfUL); 332 parentstack = (struct sparc_stackf __user *) 333 regs->u_regs[UREG_FP]; 334 335 #if 0 336 printk("clone: parent stack:\n"); 337 show_stackframe(parentstack); 338 #endif 339 340 childstack = clone_stackframe(childstack, parentstack); 341 if (!childstack) 342 return -EFAULT; 343 344 #if 0 345 printk("clone: child stack:\n"); 346 show_stackframe(childstack); 347 #endif 348 349 childregs->u_regs[UREG_FP] = (unsigned long)childstack; 350 } 351 352 #ifdef CONFIG_SMP 353 /* FPU must be disabled on SMP. */ 354 childregs->psr &= ~PSR_EF; 355 clear_tsk_thread_flag(p, TIF_USEDFPU); 356 #endif 357 358 /* Set the return value for the child. */ 359 childregs->u_regs[UREG_I0] = current->pid; 360 childregs->u_regs[UREG_I1] = 1; 361 362 /* Set the return value for the parent. */ 363 regs->u_regs[UREG_I1] = 0; 364 365 if (clone_flags & CLONE_SETTLS) 366 childregs->u_regs[UREG_G7] = tls; 367 368 return 0; 369 } 370 371 unsigned long get_wchan(struct task_struct *task) 372 { 373 unsigned long pc, fp, bias = 0; 374 unsigned long task_base = (unsigned long) task; 375 unsigned long ret = 0; 376 struct reg_window32 *rw; 377 int count = 0; 378 379 if (!task || task == current || 380 task->state == TASK_RUNNING) 381 goto out; 382 383 fp = task_thread_info(task)->ksp + bias; 384 do { 385 /* Bogus frame pointer? */ 386 if (fp < (task_base + sizeof(struct thread_info)) || 387 fp >= (task_base + (2 * PAGE_SIZE))) 388 break; 389 rw = (struct reg_window32 *) fp; 390 pc = rw->ins[7]; 391 if (!in_sched_functions(pc)) { 392 ret = pc; 393 goto out; 394 } 395 fp = rw->ins[6] + bias; 396 } while (++count < 16); 397 398 out: 399 return ret; 400 } 401 402