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