arch/unicore32/kernel/process.c

   1 /*
   2  * linux/arch/unicore32/kernel/process.c
   3  *
   4  * Code specific to PKUnity SoC and UniCore ISA
   5  *
   6  * Copyright (C) 2001-2010 GUAN Xue-tao
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12 #include <stdarg.h>
  13
  14 #include <linux/module.h>
  15 #include <linux/sched.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/kallsyms.h>
  24 #include <linux/init.h>
  25 #include <linux/cpu.h>
  26 #include <linux/elfcore.h>
  27 #include <linux/pm.h>
  28 #include <linux/tick.h>
  29 #include <linux/utsname.h>
  30 #include <linux/uaccess.h>
  31 #include <linux/random.h>
  32 #include <linux/gpio.h>
  33 #include <linux/stacktrace.h>
  34
  35 #include <asm/cacheflush.h>
  36 #include <asm/processor.h>
  37 #include <asm/system.h>
  38 #include <asm/stacktrace.h>
  39
  40 #include "setup.h"
  41
  42 static const char * const processor_modes[] = {
  43         "UK00", "UK01", "UK02", "UK03", "UK04", "UK05", "UK06", "UK07",
  44         "UK08", "UK09", "UK0A", "UK0B", "UK0C", "UK0D", "UK0E", "UK0F",
  45         "USER", "REAL", "INTR", "PRIV", "UK14", "UK15", "UK16", "ABRT",
  46         "UK18", "UK19", "UK1A", "EXTN", "UK1C", "UK1D", "UK1E", "SUSR"
  47 };
  48
  49 /*
  50  * The idle thread, has rather strange semantics for calling pm_idle,
  51  * but this is what x86 does and we need to do the same, so that
  52  * things like cpuidle get called in the same way.
  53  */
  54 void cpu_idle(void)
  55 {
  56         /* endless idle loop with no priority at all */
  57         while (1) {
  58                 tick_nohz_stop_sched_tick(1);
  59                 while (!need_resched()) {
  60                         local_irq_disable();
  61                         stop_critical_timings();
  62                         cpu_do_idle();
  63                         local_irq_enable();
  64                         start_critical_timings();
  65                 }
  66                 tick_nohz_restart_sched_tick();
  67                 preempt_enable_no_resched();
  68                 schedule();
  69                 preempt_disable();
  70         }
  71 }
  72
  73 static char reboot_mode = 'h';
  74
  75 int __init reboot_setup(char *str)
  76 {
  77         reboot_mode = str[0];
  78         return 1;
  79 }
  80
  81 __setup("reboot=", reboot_setup);
  82
  83 void machine_halt(void)
  84 {
  85         gpio_set_value(GPO_SOFT_OFF, 0);
  86 }
  87
  88 /*
  89  * Function pointers to optional machine specific functions
  90  */
  91 void (*pm_power_off)(void) = NULL;
  92
  93 void machine_power_off(void)
  94 {
  95         if (pm_power_off)
  96                 pm_power_off();
  97         machine_halt();
  98 }
  99
 100 void machine_restart(char *cmd)
 101 {
 102         /* Disable interrupts first */
 103         local_irq_disable();
 104
 105         /*
 106          * Tell the mm system that we are going to reboot -
 107          * we may need it to insert some 1:1 mappings so that
 108          * soft boot works.
 109          */
 110         setup_mm_for_reboot(reboot_mode);
 111
 112         /* Clean and invalidate caches */
 113         flush_cache_all();
 114
 115         /* Turn off caching */
 116         cpu_proc_fin();
 117
 118         /* Push out any further dirty data, and ensure cache is empty */
 119         flush_cache_all();
 120
 121         /*
 122          * Now handle reboot code.
 123          */
 124         if (reboot_mode == 's') {
 125                 /* Jump into ROM at address 0xffff0000 */
 126                 cpu_reset(VECTORS_BASE);
 127         } else {
 128                 writel(0x00002001, PM_PLLSYSCFG); /* cpu clk = 250M */
 129                 writel(0x00100800, PM_PLLDDRCFG); /* ddr clk =  44M */
 130                 writel(0x00002001, PM_PLLVGACFG); /* vga clk = 250M */
 131
 132                 /* Use on-chip reset capability */
 133                 /* following instructions must be in one icache line */
 134                 __asm__ __volatile__(
 135                         "       .align 5\n\t"
 136                         "       stw     %1, [%0]\n\t"
 137                         "201:   ldw     r0, [%0]\n\t"
 138                         "       cmpsub.a        r0, #0\n\t"
 139                         "       bne     201b\n\t"
 140                         "       stw     %3, [%2]\n\t"
 141                         "       nop; nop; nop\n\t"
 142                         /* prefetch 3 instructions at most */
 143                         :
 144                         : "r" (PM_PMCR),
 145                           "r" (PM_PMCR_CFBSYS | PM_PMCR_CFBDDR
 146                                 | PM_PMCR_CFBVGA),
 147                           "r" (RESETC_SWRR),
 148                           "r" (RESETC_SWRR_SRB)
 149                         : "r0", "memory");
 150         }
 151
 152         /*
 153          * Whoops - the architecture was unable to reboot.
 154          * Tell the user!
 155          */
 156         mdelay(1000);
 157         printk(KERN_EMERG "Reboot failed -- System halted\n");
 158         do { } while (1);
 159 }
 160
 161 void __show_regs(struct pt_regs *regs)
 162 {
 163         unsigned long flags;
 164         char buf[64];
 165
 166         printk(KERN_DEFAULT "CPU: %d    %s  (%s %.*s)\n",
 167                 raw_smp_processor_id(), print_tainted(),
 168                 init_utsname()->release,
 169                 (int)strcspn(init_utsname()->version, " "),
 170                 init_utsname()->version);
 171         print_symbol("PC is at %s\n", instruction_pointer(regs));
 172         print_symbol("LR is at %s\n", regs->UCreg_lr);
 173         printk(KERN_DEFAULT "pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 174                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 175                 regs->UCreg_pc, regs->UCreg_lr, regs->UCreg_asr,
 176                 regs->UCreg_sp, regs->UCreg_ip, regs->UCreg_fp);
 177         printk(KERN_DEFAULT "r26: %08lx  r25: %08lx  r24: %08lx\n",
 178                 regs->UCreg_26, regs->UCreg_25,
 179                 regs->UCreg_24);
 180         printk(KERN_DEFAULT "r23: %08lx  r22: %08lx  r21: %08lx  r20: %08lx\n",
 181                 regs->UCreg_23, regs->UCreg_22,
 182                 regs->UCreg_21, regs->UCreg_20);
 183         printk(KERN_DEFAULT "r19: %08lx  r18: %08lx  r17: %08lx  r16: %08lx\n",
 184                 regs->UCreg_19, regs->UCreg_18,
 185                 regs->UCreg_17, regs->UCreg_16);
 186         printk(KERN_DEFAULT "r15: %08lx  r14: %08lx  r13: %08lx  r12: %08lx\n",
 187                 regs->UCreg_15, regs->UCreg_14,
 188                 regs->UCreg_13, regs->UCreg_12);
 189         printk(KERN_DEFAULT "r11: %08lx  r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 190                 regs->UCreg_11, regs->UCreg_10,
 191                 regs->UCreg_09, regs->UCreg_08);
 192         printk(KERN_DEFAULT "r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 193                 regs->UCreg_07, regs->UCreg_06,
 194                 regs->UCreg_05, regs->UCreg_04);
 195         printk(KERN_DEFAULT "r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 196                 regs->UCreg_03, regs->UCreg_02,
 197                 regs->UCreg_01, regs->UCreg_00);
 198
 199         flags = regs->UCreg_asr;
 200         buf[0] = flags & PSR_S_BIT ? 'S' : 's';
 201         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 202         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 203         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 204         buf[4] = '\0';
 205
 206         printk(KERN_DEFAULT "Flags: %s  INTR o%s  REAL o%s  Mode %s  Segment %s\n",
 207                 buf, interrupts_enabled(regs) ? "n" : "ff",
 208                 fast_interrupts_enabled(regs) ? "n" : "ff",
 209                 processor_modes[processor_mode(regs)],
 210                 segment_eq(get_fs(), get_ds()) ? "kernel" : "user");
 211         {
 212                 unsigned int ctrl;
 213
 214                 buf[0] = '\0';
 215                 {
 216                         unsigned int transbase;
 217                         asm("movc %0, p0.c2, #0\n"
 218                             : "=r" (transbase));
 219                         snprintf(buf, sizeof(buf), "  Table: %08x", transbase);
 220                 }
 221                 asm("movc %0, p0.c1, #0\n" : "=r" (ctrl));
 222
 223                 printk(KERN_DEFAULT "Control: %08x%s\n", ctrl, buf);
 224         }
 225 }
 226
 227 void show_regs(struct pt_regs *regs)
 228 {
 229         printk(KERN_DEFAULT "\n");
 230         printk(KERN_DEFAULT "Pid: %d, comm: %20s\n",
 231                         task_pid_nr(current), current->comm);
 232         __show_regs(regs);
 233         __backtrace();
 234 }
 235
 236 /*
 237  * Free current thread data structures etc..
 238  */
 239 void exit_thread(void)
 240 {
 241 }
 242
 243 void flush_thread(void)
 244 {
 245         struct thread_info *thread = current_thread_info();
 246         struct task_struct *tsk = current;
 247
 248         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 249         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 250 #ifdef CONFIG_UNICORE_FPU_F64
 251         memset(&thread->fpstate, 0, sizeof(struct fp_state));
 252 #endif
 253 }
 254
 255 void release_thread(struct task_struct *dead_task)
 256 {
 257 }
 258
 259 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 260
 261 int
 262 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 263             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 264 {
 265         struct thread_info *thread = task_thread_info(p);
 266         struct pt_regs *childregs = task_pt_regs(p);
 267
 268         *childregs = *regs;
 269         childregs->UCreg_00 = 0;
 270         childregs->UCreg_sp = stack_start;
 271
 272         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 273         thread->cpu_context.sp = (unsigned long)childregs;
 274         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 275
 276         if (clone_flags & CLONE_SETTLS)
 277                 childregs->UCreg_16 = regs->UCreg_03;
 278
 279         return 0;
 280 }
 281
 282 /*
 283  * Fill in the task's elfregs structure for a core dump.
 284  */
 285 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 286 {
 287         elf_core_copy_regs(elfregs, task_pt_regs(t));
 288         return 1;
 289 }
 290
 291 /*
 292  * fill in the fpe structure for a core dump...
 293  */
 294 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fp)
 295 {
 296         struct thread_info *thread = current_thread_info();
 297         int used_math = thread->used_cp[1] | thread->used_cp[2];
 298
 299 #ifdef CONFIG_UNICORE_FPU_F64
 300         if (used_math)
 301                 memcpy(fp, &thread->fpstate, sizeof(*fp));
 302 #endif
 303         return used_math != 0;
 304 }
 305 EXPORT_SYMBOL(dump_fpu);
 306
 307 /*
 308  * Shuffle the argument into the correct register before calling the
 309  * thread function.  r1 is the thread argument, r2 is the pointer to
 310  * the thread function, and r3 points to the exit function.
 311  */
 312 asm(".pushsection .text\n"
 313 "       .align\n"
 314 "       .type   kernel_thread_helper, #function\n"
 315 "kernel_thread_helper:\n"
 316 "       mov.a   asr, r7\n"
 317 "       mov     r0, r4\n"
 318 "       mov     lr, r6\n"
 319 "       mov     pc, r5\n"
 320 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 321 "       .popsection");
 322
 323 /*
 324  * Create a kernel thread.
 325  */
 326 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 327 {
 328         struct pt_regs regs;
 329
 330         memset(&regs, 0, sizeof(regs));
 331
 332         regs.UCreg_04 = (unsigned long)arg;
 333         regs.UCreg_05 = (unsigned long)fn;
 334         regs.UCreg_06 = (unsigned long)do_exit;
 335         regs.UCreg_07 = PRIV_MODE;
 336         regs.UCreg_pc = (unsigned long)kernel_thread_helper;
 337         regs.UCreg_asr = regs.UCreg_07 | PSR_I_BIT;
 338
 339         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 340 }
 341 EXPORT_SYMBOL(kernel_thread);
 342
 343 unsigned long get_wchan(struct task_struct *p)
 344 {
 345         struct stackframe frame;
 346         int count = 0;
 347         if (!p || p == current || p->state == TASK_RUNNING)
 348                 return 0;
 349
 350         frame.fp = thread_saved_fp(p);
 351         frame.sp = thread_saved_sp(p);
 352         frame.lr = 0;                   /* recovered from the stack */
 353         frame.pc = thread_saved_pc(p);
 354         do {
 355                 int ret = unwind_frame(&frame);
 356                 if (ret < 0)
 357                         return 0;
 358                 if (!in_sched_functions(frame.pc))
 359                         return frame.pc;
 360         } while ((count++) < 16);
 361         return 0;
 362 }
 363
 364 unsigned long arch_randomize_brk(struct mm_struct *mm)
 365 {
 366         unsigned long range_end = mm->brk + 0x02000000;
 367         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 368 }
 369
 370 /*
 371  * The vectors page is always readable from user space for the
 372  * atomic helpers and the signal restart code.  Let's declare a mapping
 373  * for it so it is visible through ptrace and /proc/<pid>/mem.
 374  */
 375
 376 int vectors_user_mapping(void)
 377 {
 378         struct mm_struct *mm = current->mm;
 379         return install_special_mapping(mm, 0xffff0000, PAGE_SIZE,
 380                                        VM_READ | VM_EXEC |
 381                                        VM_MAYREAD | VM_MAYEXEC |
 382                                        VM_ALWAYSDUMP | VM_RESERVED,
 383                                        NULL);
 384 }
 385
 386 const char *arch_vma_name(struct vm_area_struct *vma)
 387 {
 388         return (vma->vm_start == 0xffff0000) ? "[vectors]" : NULL;
 389 }