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 #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 }
  75
  76 /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
  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
  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
 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
 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  */
 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  */
 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(&current->thread.float_regs[0], &current->thread.fsr,
 208                        &current->thread.fpqueue[0], &current->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