arch/sparc/kernel/process_32.c

   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(&current->thread.float_regs[0], &current->thread.fsr,
 212                        &current->thread.fpqueue[0], &current->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         /* This task is no longer a kernel thread. */
 221         if (current->thread.flags & SPARC_FLAG_KTHREAD) {
 222                 current->thread.flags &= ~SPARC_FLAG_KTHREAD;
 223
 224                 /* We must fixup kregs as well. */
 225                 /* XXX This was not fixed for ti for a while, worked. Unused? */
 226                 current->thread.kregs = (struct pt_regs *)
 227                     (task_stack_page(current) + (THREAD_SIZE - TRACEREG_SZ));
 228         }
 229 }
 230
 231 static inline struct sparc_stackf __user *
 232 clone_stackframe(struct sparc_stackf __user *dst,
 233                  struct sparc_stackf __user *src)
 234 {
 235         unsigned long size, fp;
 236         struct sparc_stackf *tmp;
 237         struct sparc_stackf __user *sp;
 238
 239         if (get_user(tmp, &src->fp))
 240                 return NULL;
 241
 242         fp = (unsigned long) tmp;
 243         size = (fp - ((unsigned long) src));
 244         fp = (unsigned long) dst;
 245         sp = (struct sparc_stackf __user *)(fp - size);
 246
 247         /* do_fork() grabs the parent semaphore, we must release it
 248          * temporarily so we can build the child clone stack frame
 249          * without deadlocking.
 250          */
 251         if (__copy_user(sp, src, size))
 252                 sp = NULL;
 253         else if (put_user(fp, &sp->fp))
 254                 sp = NULL;
 255
 256         return sp;
 257 }
 258
 259 /* Copy a Sparc thread.  The fork() return value conventions
 260  * under SunOS are nothing short of bletcherous:
 261  * Parent -->  %o0 == childs  pid, %o1 == 0
 262  * Child  -->  %o0 == parents pid, %o1 == 1
 263  *
 264  * NOTE: We have a separate fork kpsr/kwim because
 265  *       the parent could change these values between
 266  *       sys_fork invocation and when we reach here
 267  *       if the parent should sleep while trying to
 268  *       allocate the task_struct and kernel stack in
 269  *       do_fork().
 270  * XXX See comment above sys_vfork in sparc64. todo.
 271  */
 272 extern void ret_from_fork(void);
 273 extern void ret_from_kernel_thread(void);
 274
 275 int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
 276                 struct task_struct *p, unsigned long tls)
 277 {
 278         struct thread_info *ti = task_thread_info(p);
 279         struct pt_regs *childregs, *regs = current_pt_regs();
 280         char *new_stack;
 281
 282 #ifndef CONFIG_SMP
 283         if(last_task_used_math == current) {
 284 #else
 285         if (test_thread_flag(TIF_USEDFPU)) {
 286 #endif
 287                 put_psr(get_psr() | PSR_EF);
 288                 fpsave(&p->thread.float_regs[0], &p->thread.fsr,
 289                        &p->thread.fpqueue[0], &p->thread.fpqdepth);
 290         }
 291
 292         /*
 293          *  p->thread_info         new_stack   childregs stack bottom
 294          *  !                      !           !             !
 295          *  V                      V (stk.fr.) V  (pt_regs)  V
 296          *  +----- - - - - - ------+===========+=============+
 297          */
 298         new_stack = task_stack_page(p) + THREAD_SIZE;
 299         new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
 300         childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
 301
 302         /*
 303          * A new process must start with interrupts disabled, see schedule_tail()
 304          * and finish_task_switch(). (If we do not do it and if a timer interrupt
 305          * hits before we unlock and attempts to take the rq->lock, we deadlock.)
 306          *
 307          * Thus, kpsr |= PSR_PIL.
 308          */
 309         ti->ksp = (unsigned long) new_stack;
 310         p->thread.kregs = childregs;
 311
 312         if (unlikely(p->flags & PF_KTHREAD)) {
 313                 extern int nwindows;
 314                 unsigned long psr;
 315                 memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ);
 316                 p->thread.flags |= SPARC_FLAG_KTHREAD;
 317                 p->thread.current_ds = KERNEL_DS;
 318                 ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8);
 319                 childregs->u_regs[UREG_G1] = sp; /* function */
 320                 childregs->u_regs[UREG_G2] = arg;
 321                 psr = childregs->psr = get_psr();
 322                 ti->kpsr = psr | PSR_PIL;
 323                 ti->kwim = 1 << (((psr & PSR_CWP) + 1) % nwindows);
 324                 return 0;
 325         }
 326         memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
 327         childregs->u_regs[UREG_FP] = sp;
 328         p->thread.flags &= ~SPARC_FLAG_KTHREAD;
 329         p->thread.current_ds = USER_DS;
 330         ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
 331         ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
 332         ti->kwim = current->thread.fork_kwim;
 333
 334         if (sp != regs->u_regs[UREG_FP]) {
 335                 struct sparc_stackf __user *childstack;
 336                 struct sparc_stackf __user *parentstack;
 337
 338                 /*
 339                  * This is a clone() call with supplied user stack.
 340                  * Set some valid stack frames to give to the child.
 341                  */
 342                 childstack = (struct sparc_stackf __user *)
 343                         (sp & ~0xfUL);
 344                 parentstack = (struct sparc_stackf __user *)
 345                         regs->u_regs[UREG_FP];
 346
 347 #if 0
 348                 printk("clone: parent stack:\n");
 349                 show_stackframe(parentstack);
 350 #endif
 351
 352                 childstack = clone_stackframe(childstack, parentstack);
 353                 if (!childstack)
 354                         return -EFAULT;
 355
 356 #if 0
 357                 printk("clone: child stack:\n");
 358                 show_stackframe(childstack);
 359 #endif
 360
 361                 childregs->u_regs[UREG_FP] = (unsigned long)childstack;
 362         }
 363
 364 #ifdef CONFIG_SMP
 365         /* FPU must be disabled on SMP. */
 366         childregs->psr &= ~PSR_EF;
 367         clear_tsk_thread_flag(p, TIF_USEDFPU);
 368 #endif
 369
 370         /* Set the return value for the child. */
 371         childregs->u_regs[UREG_I0] = current->pid;
 372         childregs->u_regs[UREG_I1] = 1;
 373
 374         /* Set the return value for the parent. */
 375         regs->u_regs[UREG_I1] = 0;
 376
 377         if (clone_flags & CLONE_SETTLS)
 378                 childregs->u_regs[UREG_G7] = tls;
 379
 380         return 0;
 381 }
 382
 383 unsigned long get_wchan(struct task_struct *task)
 384 {
 385         unsigned long pc, fp, bias = 0;
 386         unsigned long task_base = (unsigned long) task;
 387         unsigned long ret = 0;
 388         struct reg_window32 *rw;
 389         int count = 0;
 390
 391         if (!task || task == current ||
 392             task->state == TASK_RUNNING)
 393                 goto out;
 394
 395         fp = task_thread_info(task)->ksp + bias;
 396         do {
 397                 /* Bogus frame pointer? */
 398                 if (fp < (task_base + sizeof(struct thread_info)) ||
 399                     fp >= (task_base + (2 * PAGE_SIZE)))
 400                         break;
 401                 rw = (struct reg_window32 *) fp;
 402                 pc = rw->ins[7];
 403                 if (!in_sched_functions(pc)) {
 404                         ret = pc;
 405                         goto out;
 406                 }
 407                 fp = rw->ins[6] + bias;
 408         } while (++count < 16);
 409
 410 out:
 411         return ret;
 412 }
 413