arch/unicore32/kernel/process.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * linux/arch/unicore32/kernel/process.c
   4  *
   5  * Code specific to PKUnity SoC and UniCore ISA
   6  *
   7  * Copyright (C) 2001-2010 GUAN Xue-tao
   8  */
   9 #include <stdarg.h>
  10
  11 #include <linux/module.h>
  12 #include <linux/sched.h>
  13 #include <linux/sched/debug.h>
  14 #include <linux/sched/task.h>
  15 #include <linux/sched/task_stack.h>
  16 #include <linux/kernel.h>
  17 #include <linux/mm.h>
  18 #include <linux/stddef.h>
  19 #include <linux/unistd.h>
  20 #include <linux/delay.h>
  21 #include <linux/reboot.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/init.h>
  24 #include <linux/cpu.h>
  25 #include <linux/elfcore.h>
  26 #include <linux/pm.h>
  27 #include <linux/tick.h>
  28 #include <linux/utsname.h>
  29 #include <linux/uaccess.h>
  30 #include <linux/random.h>
  31 #include <linux/gpio.h>
  32 #include <linux/stacktrace.h>
  33
  34 #include <asm/cacheflush.h>
  35 #include <asm/processor.h>
  36 #include <asm/stacktrace.h>
  37
  38 #include "setup.h"
  39
  40 static const char * const processor_modes[] = {
  41         "UK00", "UK01", "UK02", "UK03", "UK04", "UK05", "UK06", "UK07",
  42         "UK08", "UK09", "UK0A", "UK0B", "UK0C", "UK0D", "UK0E", "UK0F",
  43         "USER", "REAL", "INTR", "PRIV", "UK14", "UK15", "UK16", "ABRT",
  44         "UK18", "UK19", "UK1A", "EXTN", "UK1C", "UK1D", "UK1E", "SUSR"
  45 };
  46
  47 void arch_cpu_idle(void)
  48 {
  49         cpu_do_idle();
  50         local_irq_enable();
  51 }
  52
  53 void machine_halt(void)
  54 {
  55         gpio_set_value(GPO_SOFT_OFF, 0);
  56 }
  57
  58 /*
  59  * Function pointers to optional machine specific functions
  60  */
  61 void (*pm_power_off)(void) = NULL;
  62 EXPORT_SYMBOL(pm_power_off);
  63
  64 void machine_power_off(void)
  65 {
  66         if (pm_power_off)
  67                 pm_power_off();
  68         machine_halt();
  69 }
  70
  71 void machine_restart(char *cmd)
  72 {
  73         /* Disable interrupts first */
  74         local_irq_disable();
  75
  76         /*
  77          * Tell the mm system that we are going to reboot -
  78          * we may need it to insert some 1:1 mappings so that
  79          * soft boot works.
  80          */
  81         setup_mm_for_reboot();
  82
  83         /* Clean and invalidate caches */
  84         flush_cache_all();
  85
  86         /* Turn off caching */
  87         cpu_proc_fin();
  88
  89         /* Push out any further dirty data, and ensure cache is empty */
  90         flush_cache_all();
  91
  92         /*
  93          * Now handle reboot code.
  94          */
  95         if (reboot_mode == REBOOT_SOFT) {
  96                 /* Jump into ROM at address 0xffff0000 */
  97                 cpu_reset(VECTORS_BASE);
  98         } else {
  99                 writel(0x00002001, PM_PLLSYSCFG); /* cpu clk = 250M */
 100                 writel(0x00100800, PM_PLLDDRCFG); /* ddr clk =  44M */
 101                 writel(0x00002001, PM_PLLVGACFG); /* vga clk = 250M */
 102
 103                 /* Use on-chip reset capability */
 104                 /* following instructions must be in one icache line */
 105                 __asm__ __volatile__(
 106                         "       .align 5\n\t"
 107                         "       stw     %1, [%0]\n\t"
 108                         "201:   ldw     r0, [%0]\n\t"
 109                         "       cmpsub.a        r0, #0\n\t"
 110                         "       bne     201b\n\t"
 111                         "       stw     %3, [%2]\n\t"
 112                         "       nop; nop; nop\n\t"
 113                         /* prefetch 3 instructions at most */
 114                         :
 115                         : "r" (PM_PMCR),
 116                           "r" (PM_PMCR_CFBSYS | PM_PMCR_CFBDDR
 117                                 | PM_PMCR_CFBVGA),
 118                           "r" (RESETC_SWRR),
 119                           "r" (RESETC_SWRR_SRB)
 120                         : "r0", "memory");
 121         }
 122
 123         /*
 124          * Whoops - the architecture was unable to reboot.
 125          * Tell the user!
 126          */
 127         mdelay(1000);
 128         printk(KERN_EMERG "Reboot failed -- System halted\n");
 129         do { } while (1);
 130 }
 131
 132 void __show_regs(struct pt_regs *regs)
 133 {
 134         unsigned long flags;
 135         char buf[64];
 136
 137         show_regs_print_info(KERN_DEFAULT);
 138         printk("PC is at %pS\n", (void *)instruction_pointer(regs));
 139         printk("LR is at %pS\n", (void *)regs->UCreg_lr);
 140         printk(KERN_DEFAULT "pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 141                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 142                 regs->UCreg_pc, regs->UCreg_lr, regs->UCreg_asr,
 143                 regs->UCreg_sp, regs->UCreg_ip, regs->UCreg_fp);
 144         printk(KERN_DEFAULT "r26: %08lx  r25: %08lx  r24: %08lx\n",
 145                 regs->UCreg_26, regs->UCreg_25,
 146                 regs->UCreg_24);
 147         printk(KERN_DEFAULT "r23: %08lx  r22: %08lx  r21: %08lx  r20: %08lx\n",
 148                 regs->UCreg_23, regs->UCreg_22,
 149                 regs->UCreg_21, regs->UCreg_20);
 150         printk(KERN_DEFAULT "r19: %08lx  r18: %08lx  r17: %08lx  r16: %08lx\n",
 151                 regs->UCreg_19, regs->UCreg_18,
 152                 regs->UCreg_17, regs->UCreg_16);
 153         printk(KERN_DEFAULT "r15: %08lx  r14: %08lx  r13: %08lx  r12: %08lx\n",
 154                 regs->UCreg_15, regs->UCreg_14,
 155                 regs->UCreg_13, regs->UCreg_12);
 156         printk(KERN_DEFAULT "r11: %08lx  r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 157                 regs->UCreg_11, regs->UCreg_10,
 158                 regs->UCreg_09, regs->UCreg_08);
 159         printk(KERN_DEFAULT "r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 160                 regs->UCreg_07, regs->UCreg_06,
 161                 regs->UCreg_05, regs->UCreg_04);
 162         printk(KERN_DEFAULT "r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 163                 regs->UCreg_03, regs->UCreg_02,
 164                 regs->UCreg_01, regs->UCreg_00);
 165
 166         flags = regs->UCreg_asr;
 167         buf[0] = flags & PSR_S_BIT ? 'S' : 's';
 168         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 169         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 170         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 171         buf[4] = '\0';
 172
 173         printk(KERN_DEFAULT "Flags: %s  INTR o%s  REAL o%s  Mode %s  Segment %s\n",
 174                 buf, interrupts_enabled(regs) ? "n" : "ff",
 175                 fast_interrupts_enabled(regs) ? "n" : "ff",
 176                 processor_modes[processor_mode(regs)],
 177                 uaccess_kernel() ? "kernel" : "user");
 178         {
 179                 unsigned int ctrl;
 180
 181                 buf[0] = '\0';
 182                 {
 183                         unsigned int transbase;
 184                         asm("movc %0, p0.c2, #0\n"
 185                             : "=r" (transbase));
 186                         snprintf(buf, sizeof(buf), "  Table: %08x", transbase);
 187                 }
 188                 asm("movc %0, p0.c1, #0\n" : "=r" (ctrl));
 189
 190                 printk(KERN_DEFAULT "Control: %08x%s\n", ctrl, buf);
 191         }
 192 }
 193
 194 void show_regs(struct pt_regs *regs)
 195 {
 196         printk(KERN_DEFAULT "\n");
 197         printk(KERN_DEFAULT "Pid: %d, comm: %20s\n",
 198                         task_pid_nr(current), current->comm);
 199         __show_regs(regs);
 200         __backtrace();
 201 }
 202
 203 void flush_thread(void)
 204 {
 205         struct thread_info *thread = current_thread_info();
 206         struct task_struct *tsk = current;
 207
 208         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 209         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 210 #ifdef CONFIG_UNICORE_FPU_F64
 211         memset(&thread->fpstate, 0, sizeof(struct fp_state));
 212 #endif
 213 }
 214
 215 void release_thread(struct task_struct *dead_task)
 216 {
 217 }
 218
 219 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 220 asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread");
 221
 222 int
 223 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 224             unsigned long stk_sz, struct task_struct *p)
 225 {
 226         struct thread_info *thread = task_thread_info(p);
 227         struct pt_regs *childregs = task_pt_regs(p);
 228
 229         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 230         thread->cpu_context.sp = (unsigned long)childregs;
 231         if (unlikely(p->flags & PF_KTHREAD)) {
 232                 thread->cpu_context.pc = (unsigned long)ret_from_kernel_thread;
 233                 thread->cpu_context.r4 = stack_start;
 234                 thread->cpu_context.r5 = stk_sz;
 235                 memset(childregs, 0, sizeof(struct pt_regs));
 236         } else {
 237                 thread->cpu_context.pc = (unsigned long)ret_from_fork;
 238                 *childregs = *current_pt_regs();
 239                 childregs->UCreg_00 = 0;
 240                 if (stack_start)
 241                         childregs->UCreg_sp = stack_start;
 242
 243                 if (clone_flags & CLONE_SETTLS)
 244                         childregs->UCreg_16 = childregs->UCreg_03;
 245         }
 246         return 0;
 247 }
 248
 249 /*
 250  * Fill in the task's elfregs structure for a core dump.
 251  */
 252 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 253 {
 254         elf_core_copy_regs(elfregs, task_pt_regs(t));
 255         return 1;
 256 }
 257
 258 /*
 259  * fill in the fpe structure for a core dump...
 260  */
 261 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fp)
 262 {
 263         struct thread_info *thread = current_thread_info();
 264         int used_math = thread->used_cp[1] | thread->used_cp[2];
 265
 266 #ifdef CONFIG_UNICORE_FPU_F64
 267         if (used_math)
 268                 memcpy(fp, &thread->fpstate, sizeof(*fp));
 269 #endif
 270         return used_math != 0;
 271 }
 272 EXPORT_SYMBOL(dump_fpu);
 273
 274 unsigned long get_wchan(struct task_struct *p)
 275 {
 276         struct stackframe frame;
 277         int count = 0;
 278         if (!p || p == current || p->state == TASK_RUNNING)
 279                 return 0;
 280
 281         frame.fp = thread_saved_fp(p);
 282         frame.sp = thread_saved_sp(p);
 283         frame.lr = 0;                   /* recovered from the stack */
 284         frame.pc = thread_saved_pc(p);
 285         do {
 286                 int ret = unwind_frame(&frame);
 287                 if (ret < 0)
 288                         return 0;
 289                 if (!in_sched_functions(frame.pc))
 290                         return frame.pc;
 291         } while ((count++) < 16);
 292         return 0;
 293 }
 294
 295 unsigned long arch_randomize_brk(struct mm_struct *mm)
 296 {
 297         return randomize_page(mm->brk, 0x02000000);
 298 }
 299
 300 /*
 301  * The vectors page is always readable from user space for the
 302  * atomic helpers and the signal restart code.  Let's declare a mapping
 303  * for it so it is visible through ptrace and /proc/<pid>/mem.
 304  */
 305
 306 int vectors_user_mapping(void)
 307 {
 308         struct mm_struct *mm = current->mm;
 309         return install_special_mapping(mm, 0xffff0000, PAGE_SIZE,
 310                                        VM_READ | VM_EXEC |
 311                                        VM_MAYREAD | VM_MAYEXEC |
 312                                        VM_DONTEXPAND | VM_DONTDUMP,
 313                                        NULL);
 314 }
 315
 316 const char *arch_vma_name(struct vm_area_struct *vma)
 317 {
 318         return (vma->vm_start == 0xffff0000) ? "[vectors]" : NULL;
 319 }