sparc/kernel/process_32.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*  linux/arch/sparc/kernel/process.c
0003  *
0004  *  Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net)
0005  *  Copyright (C) 1996 Eddie C. Dost   (ecd@skynet.be)
0006  */
0007
0008 /*
0009  * This file handles the architecture-dependent parts of process handling..
0010  */
0011 #include <linux/elfcore.h>
0012 #include <linux/errno.h>
0013 #include <linux/module.h>
0014 #include <linux/sched.h>
0015 #include <linux/sched/debug.h>
0016 #include <linux/sched/task.h>
0017 #include <linux/sched/task_stack.h>
0018 #include <linux/kernel.h>
0019 #include <linux/mm.h>
0020 #include <linux/stddef.h>
0021 #include <linux/ptrace.h>
0022 #include <linux/user.h>
0023 #include <linux/smp.h>
0024 #include <linux/reboot.h>
0025 #include <linux/delay.h>
0026 #include <linux/pm.h>
0027 #include <linux/slab.h>
0028 #include <linux/cpu.h>
0029
0030 #include <asm/auxio.h>
0031 #include <asm/oplib.h>
0032 #include <linux/uaccess.h>
0033 #include <asm/page.h>
0034 #include <asm/delay.h>
0035 #include <asm/processor.h>
0036 #include <asm/psr.h>
0037 #include <asm/elf.h>
0038 #include <asm/prom.h>
0039 #include <asm/unistd.h>
0040 #include <asm/setup.h>
0041
0042 #include "kernel.h"
0043
0044 /*
0045  * Power management idle function
0046  * Set in pm platform drivers (apc.c and pmc.c)
0047  */
0048 void (*sparc_idle)(void);
0049
0050 /*
0051  * Power-off handler instantiation for pm.h compliance
0052  * This is done via auxio, but could be used as a fallback
0053  * handler when auxio is not present-- unused for now...
0054  */
0055 void (*pm_power_off)(void) = machine_power_off;
0056 EXPORT_SYMBOL(pm_power_off);
0057
0058 /*
0059  * sysctl - toggle power-off restriction for serial console
0060  * systems in machine_power_off()
0061  */
0062 int scons_pwroff = 1;
0063
0064 extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
0065
0066 struct task_struct *last_task_used_math = NULL;
0067 struct thread_info *current_set[NR_CPUS];
0068
0069 /* Idle loop support. */
0070 void arch_cpu_idle(void)
0071 {
0072     if (sparc_idle)
0073         (*sparc_idle)();
0074     raw_local_irq_enable();
0075 }
0076
0077 /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
0078 void machine_halt(void)
0079 {
0080     local_irq_enable();
0081     mdelay(8);
0082     local_irq_disable();
0083     prom_halt();
0084     panic("Halt failed!");
0085 }
0086
0087 void machine_restart(char * cmd)
0088 {
0089     char *p;
0090
0091     local_irq_enable();
0092     mdelay(8);
0093     local_irq_disable();
0094
0095     p = strchr (reboot_command, '\n');
0096     if (p) *p = 0;
0097     if (cmd)
0098         prom_reboot(cmd);
0099     if (*reboot_command)
0100         prom_reboot(reboot_command);
0101     prom_feval ("reset");
0102     panic("Reboot failed!");
0103 }
0104
0105 void machine_power_off(void)
0106 {
0107     if (auxio_power_register &&
0108         (!of_node_is_type(of_console_device, "serial") || scons_pwroff)) {
0109         u8 power_register = sbus_readb(auxio_power_register);
0110         power_register |= AUXIO_POWER_OFF;
0111         sbus_writeb(power_register, auxio_power_register);
0112     }
0113
0114     machine_halt();
0115 }
0116
0117 void show_regs(struct pt_regs *r)
0118 {
0119     struct reg_window32 *rw = (struct reg_window32 *) r->u_regs[14];
0120
0121     show_regs_print_info(KERN_DEFAULT);
0122
0123         printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx    %s\n",
0124            r->psr, r->pc, r->npc, r->y, print_tainted());
0125     printk("PC: <%pS>\n", (void *) r->pc);
0126     printk("%%G: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
0127            r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3],
0128            r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]);
0129     printk("%%O: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
0130            r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11],
0131            r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]);
0132     printk("RPC: <%pS>\n", (void *) r->u_regs[15]);
0133
0134     printk("%%L: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
0135            rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3],
0136            rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]);
0137     printk("%%I: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
0138            rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
0139            rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]);
0140 }
0141
0142 /*
0143  * The show_stack() is external API which we do not use ourselves.
0144  * The oops is printed in die_if_kernel.
0145  */
0146 void show_stack(struct task_struct *tsk, unsigned long *_ksp, const char *loglvl)
0147 {
0148     unsigned long pc, fp;
0149     unsigned long task_base;
0150     struct reg_window32 *rw;
0151     int count = 0;
0152
0153     if (!tsk)
0154         tsk = current;
0155
0156     if (tsk == current && !_ksp)
0157         __asm__ __volatile__("mov   %%fp, %0" : "=r" (_ksp));
0158
0159     task_base = (unsigned long) task_stack_page(tsk);
0160     fp = (unsigned long) _ksp;
0161     do {
0162         /* Bogus frame pointer? */
0163         if (fp < (task_base + sizeof(struct thread_info)) ||
0164             fp >= (task_base + (PAGE_SIZE << 1)))
0165             break;
0166         rw = (struct reg_window32 *) fp;
0167         pc = rw->ins[7];
0168         printk("%s[%08lx : ", loglvl, pc);
0169         printk("%s%pS ] ", loglvl, (void *) pc);
0170         fp = rw->ins[6];
0171     } while (++count < 16);
0172     printk("%s\n", loglvl);
0173 }
0174
0175 /*
0176  * Free current thread data structures etc..
0177  */
0178 void exit_thread(struct task_struct *tsk)
0179 {
0180 #ifndef CONFIG_SMP
0181     if (last_task_used_math == tsk) {
0182 #else
0183     if (test_tsk_thread_flag(tsk, TIF_USEDFPU)) {
0184 #endif
0185         /* Keep process from leaving FPU in a bogon state. */
0186         put_psr(get_psr() | PSR_EF);
0187         fpsave(&tsk->thread.float_regs[0], &tsk->thread.fsr,
0188                &tsk->thread.fpqueue[0], &tsk->thread.fpqdepth);
0189 #ifndef CONFIG_SMP
0190         last_task_used_math = NULL;
0191 #else
0192         clear_ti_thread_flag(task_thread_info(tsk), TIF_USEDFPU);
0193 #endif
0194     }
0195 }
0196
0197 void flush_thread(void)
0198 {
0199     current_thread_info()->w_saved = 0;
0200
0201 #ifndef CONFIG_SMP
0202     if(last_task_used_math == current) {
0203 #else
0204     if (test_thread_flag(TIF_USEDFPU)) {
0205 #endif
0206         /* Clean the fpu. */
0207         put_psr(get_psr() | PSR_EF);
0208         fpsave(&current->thread.float_regs[0], &current->thread.fsr,
0209                &current->thread.fpqueue[0], &current->thread.fpqdepth);
0210 #ifndef CONFIG_SMP
0211         last_task_used_math = NULL;
0212 #else
0213         clear_thread_flag(TIF_USEDFPU);
0214 #endif
0215     }
0216 }
0217
0218 static inline struct sparc_stackf __user *
0219 clone_stackframe(struct sparc_stackf __user *dst,
0220          struct sparc_stackf __user *src)
0221 {
0222     unsigned long size, fp;
0223     struct sparc_stackf *tmp;
0224     struct sparc_stackf __user *sp;
0225
0226     if (get_user(tmp, &src->fp))
0227         return NULL;
0228
0229     fp = (unsigned long) tmp;
0230     size = (fp - ((unsigned long) src));
0231     fp = (unsigned long) dst;
0232     sp = (struct sparc_stackf __user *)(fp - size);
0233
0234     /* do_fork() grabs the parent semaphore, we must release it
0235      * temporarily so we can build the child clone stack frame
0236      * without deadlocking.
0237      */
0238     if (__copy_user(sp, src, size))
0239         sp = NULL;
0240     else if (put_user(fp, &sp->fp))
0241         sp = NULL;
0242
0243     return sp;
0244 }
0245
0246 /* Copy a Sparc thread.  The fork() return value conventions
0247  * under SunOS are nothing short of bletcherous:
0248  * Parent -->  %o0 == childs  pid, %o1 == 0
0249  * Child  -->  %o0 == parents pid, %o1 == 1
0250  *
0251  * NOTE: We have a separate fork kpsr/kwim because
0252  *       the parent could change these values between
0253  *       sys_fork invocation and when we reach here
0254  *       if the parent should sleep while trying to
0255  *       allocate the task_struct and kernel stack in
0256  *       do_fork().
0257  * XXX See comment above sys_vfork in sparc64. todo.
0258  */
0259 extern void ret_from_fork(void);
0260 extern void ret_from_kernel_thread(void);
0261
0262 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
0263 {
0264     unsigned long clone_flags = args->flags;
0265     unsigned long sp = args->stack;
0266     unsigned long tls = args->tls;
0267     struct thread_info *ti = task_thread_info(p);
0268     struct pt_regs *childregs, *regs = current_pt_regs();
0269     char *new_stack;
0270
0271 #ifndef CONFIG_SMP
0272     if(last_task_used_math == current) {
0273 #else
0274     if (test_thread_flag(TIF_USEDFPU)) {
0275 #endif
0276         put_psr(get_psr() | PSR_EF);
0277         fpsave(&p->thread.float_regs[0], &p->thread.fsr,
0278                &p->thread.fpqueue[0], &p->thread.fpqdepth);
0279     }
0280
0281     /*
0282      *  p->thread_info         new_stack   childregs stack bottom
0283      *  !                      !           !             !
0284      *  V                      V (stk.fr.) V  (pt_regs)  V
0285      *  +----- - - - - - ------+===========+=============+
0286      */
0287     new_stack = task_stack_page(p) + THREAD_SIZE;
0288     new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
0289     childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
0290
0291     /*
0292      * A new process must start with interrupts disabled, see schedule_tail()
0293      * and finish_task_switch(). (If we do not do it and if a timer interrupt
0294      * hits before we unlock and attempts to take the rq->lock, we deadlock.)
0295      *
0296      * Thus, kpsr |= PSR_PIL.
0297      */
0298     ti->ksp = (unsigned long) new_stack;
0299     p->thread.kregs = childregs;
0300
0301     if (unlikely(args->fn)) {
0302         extern int nwindows;
0303         unsigned long psr;
0304         memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ);
0305         ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8);
0306         childregs->u_regs[UREG_G1] = (unsigned long) args->fn;
0307         childregs->u_regs[UREG_G2] = (unsigned long) args->fn_arg;
0308         psr = childregs->psr = get_psr();
0309         ti->kpsr = psr | PSR_PIL;
0310         ti->kwim = 1 << (((psr & PSR_CWP) + 1) % nwindows);
0311         return 0;
0312     }
0313     memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
0314     childregs->u_regs[UREG_FP] = sp;
0315     ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
0316     ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
0317     ti->kwim = current->thread.fork_kwim;
0318
0319     if (sp != regs->u_regs[UREG_FP]) {
0320         struct sparc_stackf __user *childstack;
0321         struct sparc_stackf __user *parentstack;
0322
0323         /*
0324          * This is a clone() call with supplied user stack.
0325          * Set some valid stack frames to give to the child.
0326          */
0327         childstack = (struct sparc_stackf __user *)
0328             (sp & ~0xfUL);
0329         parentstack = (struct sparc_stackf __user *)
0330             regs->u_regs[UREG_FP];
0331
0332 #if 0
0333         printk("clone: parent stack:\n");
0334         show_stackframe(parentstack);
0335 #endif
0336
0337         childstack = clone_stackframe(childstack, parentstack);
0338         if (!childstack)
0339             return -EFAULT;
0340
0341 #if 0
0342         printk("clone: child stack:\n");
0343         show_stackframe(childstack);
0344 #endif
0345
0346         childregs->u_regs[UREG_FP] = (unsigned long)childstack;
0347     }
0348
0349 #ifdef CONFIG_SMP
0350     /* FPU must be disabled on SMP. */
0351     childregs->psr &= ~PSR_EF;
0352     clear_tsk_thread_flag(p, TIF_USEDFPU);
0353 #endif
0354
0355     /* Set the return value for the child. */
0356     childregs->u_regs[UREG_I0] = current->pid;
0357     childregs->u_regs[UREG_I1] = 1;
0358
0359     /* Set the return value for the parent. */
0360     regs->u_regs[UREG_I1] = 0;
0361
0362     if (clone_flags & CLONE_SETTLS)
0363         childregs->u_regs[UREG_G7] = tls;
0364
0365     return 0;
0366 }
0367
0368 unsigned long __get_wchan(struct task_struct *task)
0369 {
0370     unsigned long pc, fp, bias = 0;
0371     unsigned long task_base = (unsigned long) task;
0372         unsigned long ret = 0;
0373     struct reg_window32 *rw;
0374     int count = 0;
0375
0376     fp = task_thread_info(task)->ksp + bias;
0377     do {
0378         /* Bogus frame pointer? */
0379         if (fp < (task_base + sizeof(struct thread_info)) ||
0380             fp >= (task_base + (2 * PAGE_SIZE)))
0381             break;
0382         rw = (struct reg_window32 *) fp;
0383         pc = rw->ins[7];
0384         if (!in_sched_functions(pc)) {
0385             ret = pc;
0386             goto out;
0387         }
0388         fp = rw->ins[6] + bias;
0389     } while (++count < 16);
0390
0391 out:
0392     return ret;
0393 }
0394