linux/arch/unicore32/kernel/process.c
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   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/sched/debug.h>
  17#include <linux/sched/task.h>
  18#include <linux/sched/task_stack.h>
  19#include <linux/kernel.h>
  20#include <linux/mm.h>
  21#include <linux/stddef.h>
  22#include <linux/unistd.h>
  23#include <linux/delay.h>
  24#include <linux/reboot.h>
  25#include <linux/interrupt.h>
  26#include <linux/init.h>
  27#include <linux/cpu.h>
  28#include <linux/elfcore.h>
  29#include <linux/pm.h>
  30#include <linux/tick.h>
  31#include <linux/utsname.h>
  32#include <linux/uaccess.h>
  33#include <linux/random.h>
  34#include <linux/gpio.h>
  35#include <linux/stacktrace.h>
  36
  37#include <asm/cacheflush.h>
  38#include <asm/processor.h>
  39#include <asm/stacktrace.h>
  40
  41#include "setup.h"
  42
  43static const char * const processor_modes[] = {
  44        "UK00", "UK01", "UK02", "UK03", "UK04", "UK05", "UK06", "UK07",
  45        "UK08", "UK09", "UK0A", "UK0B", "UK0C", "UK0D", "UK0E", "UK0F",
  46        "USER", "REAL", "INTR", "PRIV", "UK14", "UK15", "UK16", "ABRT",
  47        "UK18", "UK19", "UK1A", "EXTN", "UK1C", "UK1D", "UK1E", "SUSR"
  48};
  49
  50void arch_cpu_idle(void)
  51{
  52        cpu_do_idle();
  53        local_irq_enable();
  54}
  55
  56void machine_halt(void)
  57{
  58        gpio_set_value(GPO_SOFT_OFF, 0);
  59}
  60
  61/*
  62 * Function pointers to optional machine specific functions
  63 */
  64void (*pm_power_off)(void) = NULL;
  65EXPORT_SYMBOL(pm_power_off);
  66
  67void machine_power_off(void)
  68{
  69        if (pm_power_off)
  70                pm_power_off();
  71        machine_halt();
  72}
  73
  74void machine_restart(char *cmd)
  75{
  76        /* Disable interrupts first */
  77        local_irq_disable();
  78
  79        /*
  80         * Tell the mm system that we are going to reboot -
  81         * we may need it to insert some 1:1 mappings so that
  82         * soft boot works.
  83         */
  84        setup_mm_for_reboot();
  85
  86        /* Clean and invalidate caches */
  87        flush_cache_all();
  88
  89        /* Turn off caching */
  90        cpu_proc_fin();
  91
  92        /* Push out any further dirty data, and ensure cache is empty */
  93        flush_cache_all();
  94
  95        /*
  96         * Now handle reboot code.
  97         */
  98        if (reboot_mode == REBOOT_SOFT) {
  99                /* Jump into ROM at address 0xffff0000 */
 100                cpu_reset(VECTORS_BASE);
 101        } else {
 102                writel(0x00002001, PM_PLLSYSCFG); /* cpu clk = 250M */
 103                writel(0x00100800, PM_PLLDDRCFG); /* ddr clk =  44M */
 104                writel(0x00002001, PM_PLLVGACFG); /* vga clk = 250M */
 105
 106                /* Use on-chip reset capability */
 107                /* following instructions must be in one icache line */
 108                __asm__ __volatile__(
 109                        "       .align 5\n\t"
 110                        "       stw     %1, [%0]\n\t"
 111                        "201:   ldw     r0, [%0]\n\t"
 112                        "       cmpsub.a        r0, #0\n\t"
 113                        "       bne     201b\n\t"
 114                        "       stw     %3, [%2]\n\t"
 115                        "       nop; nop; nop\n\t"
 116                        /* prefetch 3 instructions at most */
 117                        :
 118                        : "r" (PM_PMCR),
 119                          "r" (PM_PMCR_CFBSYS | PM_PMCR_CFBDDR
 120                                | PM_PMCR_CFBVGA),
 121                          "r" (RESETC_SWRR),
 122                          "r" (RESETC_SWRR_SRB)
 123                        : "r0", "memory");
 124        }
 125
 126        /*
 127         * Whoops - the architecture was unable to reboot.
 128         * Tell the user!
 129         */
 130        mdelay(1000);
 131        printk(KERN_EMERG "Reboot failed -- System halted\n");
 132        do { } while (1);
 133}
 134
 135void __show_regs(struct pt_regs *regs)
 136{
 137        unsigned long flags;
 138        char buf[64];
 139
 140        show_regs_print_info(KERN_DEFAULT);
 141        printk("PC is at %pS\n", (void *)instruction_pointer(regs));
 142        printk("LR is at %pS\n", (void *)regs->UCreg_lr);
 143        printk(KERN_DEFAULT "pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 144               "sp : %08lx  ip : %08lx  fp : %08lx\n",
 145                regs->UCreg_pc, regs->UCreg_lr, regs->UCreg_asr,
 146                regs->UCreg_sp, regs->UCreg_ip, regs->UCreg_fp);
 147        printk(KERN_DEFAULT "r26: %08lx  r25: %08lx  r24: %08lx\n",
 148                regs->UCreg_26, regs->UCreg_25,
 149                regs->UCreg_24);
 150        printk(KERN_DEFAULT "r23: %08lx  r22: %08lx  r21: %08lx  r20: %08lx\n",
 151                regs->UCreg_23, regs->UCreg_22,
 152                regs->UCreg_21, regs->UCreg_20);
 153        printk(KERN_DEFAULT "r19: %08lx  r18: %08lx  r17: %08lx  r16: %08lx\n",
 154                regs->UCreg_19, regs->UCreg_18,
 155                regs->UCreg_17, regs->UCreg_16);
 156        printk(KERN_DEFAULT "r15: %08lx  r14: %08lx  r13: %08lx  r12: %08lx\n",
 157                regs->UCreg_15, regs->UCreg_14,
 158                regs->UCreg_13, regs->UCreg_12);
 159        printk(KERN_DEFAULT "r11: %08lx  r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 160                regs->UCreg_11, regs->UCreg_10,
 161                regs->UCreg_09, regs->UCreg_08);
 162        printk(KERN_DEFAULT "r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 163                regs->UCreg_07, regs->UCreg_06,
 164                regs->UCreg_05, regs->UCreg_04);
 165        printk(KERN_DEFAULT "r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 166                regs->UCreg_03, regs->UCreg_02,
 167                regs->UCreg_01, regs->UCreg_00);
 168
 169        flags = regs->UCreg_asr;
 170        buf[0] = flags & PSR_S_BIT ? 'S' : 's';
 171        buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 172        buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 173        buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 174        buf[4] = '\0';
 175
 176        printk(KERN_DEFAULT "Flags: %s  INTR o%s  REAL o%s  Mode %s  Segment %s\n",
 177                buf, interrupts_enabled(regs) ? "n" : "ff",
 178                fast_interrupts_enabled(regs) ? "n" : "ff",
 179                processor_modes[processor_mode(regs)],
 180                uaccess_kernel() ? "kernel" : "user");
 181        {
 182                unsigned int ctrl;
 183
 184                buf[0] = '\0';
 185                {
 186                        unsigned int transbase;
 187                        asm("movc %0, p0.c2, #0\n"
 188                            : "=r" (transbase));
 189                        snprintf(buf, sizeof(buf), "  Table: %08x", transbase);
 190                }
 191                asm("movc %0, p0.c1, #0\n" : "=r" (ctrl));
 192
 193                printk(KERN_DEFAULT "Control: %08x%s\n", ctrl, buf);
 194        }
 195}
 196
 197void show_regs(struct pt_regs *regs)
 198{
 199        printk(KERN_DEFAULT "\n");
 200        printk(KERN_DEFAULT "Pid: %d, comm: %20s\n",
 201                        task_pid_nr(current), current->comm);
 202        __show_regs(regs);
 203        __backtrace();
 204}
 205
 206void flush_thread(void)
 207{
 208        struct thread_info *thread = current_thread_info();
 209        struct task_struct *tsk = current;
 210
 211        memset(thread->used_cp, 0, sizeof(thread->used_cp));
 212        memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 213#ifdef CONFIG_UNICORE_FPU_F64
 214        memset(&thread->fpstate, 0, sizeof(struct fp_state));
 215#endif
 216}
 217
 218void release_thread(struct task_struct *dead_task)
 219{
 220}
 221
 222asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 223asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread");
 224
 225int
 226copy_thread(unsigned long clone_flags, unsigned long stack_start,
 227            unsigned long stk_sz, struct task_struct *p)
 228{
 229        struct thread_info *thread = task_thread_info(p);
 230        struct pt_regs *childregs = task_pt_regs(p);
 231
 232        memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 233        thread->cpu_context.sp = (unsigned long)childregs;
 234        if (unlikely(p->flags & PF_KTHREAD)) {
 235                thread->cpu_context.pc = (unsigned long)ret_from_kernel_thread;
 236                thread->cpu_context.r4 = stack_start;
 237                thread->cpu_context.r5 = stk_sz;
 238                memset(childregs, 0, sizeof(struct pt_regs));
 239        } else {
 240                thread->cpu_context.pc = (unsigned long)ret_from_fork;
 241                *childregs = *current_pt_regs();
 242                childregs->UCreg_00 = 0;
 243                if (stack_start)
 244                        childregs->UCreg_sp = stack_start;
 245
 246                if (clone_flags & CLONE_SETTLS)
 247                        childregs->UCreg_16 = childregs->UCreg_03;
 248        }
 249        return 0;
 250}
 251
 252/*
 253 * Fill in the task's elfregs structure for a core dump.
 254 */
 255int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 256{
 257        elf_core_copy_regs(elfregs, task_pt_regs(t));
 258        return 1;
 259}
 260
 261/*
 262 * fill in the fpe structure for a core dump...
 263 */
 264int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fp)
 265{
 266        struct thread_info *thread = current_thread_info();
 267        int used_math = thread->used_cp[1] | thread->used_cp[2];
 268
 269#ifdef CONFIG_UNICORE_FPU_F64
 270        if (used_math)
 271                memcpy(fp, &thread->fpstate, sizeof(*fp));
 272#endif
 273        return used_math != 0;
 274}
 275EXPORT_SYMBOL(dump_fpu);
 276
 277unsigned long get_wchan(struct task_struct *p)
 278{
 279        struct stackframe frame;
 280        int count = 0;
 281        if (!p || p == current || p->state == TASK_RUNNING)
 282                return 0;
 283
 284        frame.fp = thread_saved_fp(p);
 285        frame.sp = thread_saved_sp(p);
 286        frame.lr = 0;                   /* recovered from the stack */
 287        frame.pc = thread_saved_pc(p);
 288        do {
 289                int ret = unwind_frame(&frame);
 290                if (ret < 0)
 291                        return 0;
 292                if (!in_sched_functions(frame.pc))
 293                        return frame.pc;
 294        } while ((count++) < 16);
 295        return 0;
 296}
 297
 298unsigned long arch_randomize_brk(struct mm_struct *mm)
 299{
 300        return randomize_page(mm->brk, 0x02000000);
 301}
 302
 303/*
 304 * The vectors page is always readable from user space for the
 305 * atomic helpers and the signal restart code.  Let's declare a mapping
 306 * for it so it is visible through ptrace and /proc/<pid>/mem.
 307 */
 308
 309int vectors_user_mapping(void)
 310{
 311        struct mm_struct *mm = current->mm;
 312        return install_special_mapping(mm, 0xffff0000, PAGE_SIZE,
 313                                       VM_READ | VM_EXEC |
 314                                       VM_MAYREAD | VM_MAYEXEC |
 315                                       VM_DONTEXPAND | VM_DONTDUMP,
 316                                       NULL);
 317}
 318
 319const char *arch_vma_name(struct vm_area_struct *vma)
 320{
 321        return (vma->vm_start == 0xffff0000) ? "[vectors]" : NULL;
 322}
 323