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