arch/blackfin/kernel/process.c

   1 /*
   2  * File:         arch/blackfin/kernel/process.c
   3  * Based on:
   4  * Author:
   5  *
   6  * Created:
   7  * Description:  Blackfin architecture-dependent process handling.
   8  *
   9  * Modified:
  10  *               Copyright 2004-2006 Analog Devices Inc.
  11  *
  12  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, see the file COPYING, or write
  26  * to the Free Software Foundation, Inc.,
  27  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  28  */
  29
  30 #include <linux/module.h>
  31 #include <linux/smp_lock.h>
  32 #include <linux/unistd.h>
  33 #include <linux/user.h>
  34 #include <linux/a.out.h>
  35
  36 #include <asm/blackfin.h>
  37 #include <asm/uaccess.h>
  38
  39 #define LED_ON  0
  40 #define LED_OFF 1
  41
  42 asmlinkage void ret_from_fork(void);
  43
  44 /* Points to the SDRAM backup memory for the stack that is currently in
  45  * L1 scratchpad memory.
  46  */
  47 void *current_l1_stack_save;
  48
  49 /* The number of tasks currently using a L1 stack area.  The SRAM is
  50  * allocated/deallocated whenever this changes from/to zero.
  51  */
  52 int nr_l1stack_tasks;
  53
  54 /* Start and length of the area in L1 scratchpad memory which we've allocated
  55  * for process stacks.
  56  */
  57 void *l1_stack_base;
  58 unsigned long l1_stack_len;
  59
  60 /*
  61  * Powermanagement idle function, if any..
  62  */
  63 void (*pm_idle)(void) = NULL;
  64 EXPORT_SYMBOL(pm_idle);
  65
  66 void (*pm_power_off)(void) = NULL;
  67 EXPORT_SYMBOL(pm_power_off);
  68
  69 /*
  70  * We are using a different LED from the one used to indicate timer interrupt.
  71  */
  72 #if defined(CONFIG_BFIN_IDLE_LED)
  73 static inline void leds_switch(int flag)
  74 {
  75         unsigned short tmp = 0;
  76
  77         tmp = bfin_read_CONFIG_BFIN_IDLE_LED_PORT();
  78         SSYNC();
  79
  80         if (flag == LED_ON)
  81                 tmp &= ~CONFIG_BFIN_IDLE_LED_PIN;       /* light on */
  82         else
  83                 tmp |= CONFIG_BFIN_IDLE_LED_PIN;        /* light off */
  84
  85         bfin_write_CONFIG_BFIN_IDLE_LED_PORT(tmp);
  86         SSYNC();
  87
  88 }
  89 #else
  90 static inline void leds_switch(int flag)
  91 {
  92 }
  93 #endif
  94
  95 /*
  96  * The idle loop on BFIN
  97  */
  98 #ifdef CONFIG_IDLE_L1
  99 void default_idle(void)__attribute__((l1_text));
 100 void cpu_idle(void)__attribute__((l1_text));
 101 #endif
 102
 103 void default_idle(void)
 104 {
 105         while (!need_resched()) {
 106                 leds_switch(LED_OFF);
 107                 local_irq_disable();
 108                 if (likely(!need_resched()))
 109                         idle_with_irq_disabled();
 110                 local_irq_enable();
 111                 leds_switch(LED_ON);
 112         }
 113 }
 114
 115 void (*idle)(void) = default_idle;
 116
 117 /*
 118  * The idle thread. There's no useful work to be
 119  * done, so just try to conserve power and have a
 120  * low exit latency (ie sit in a loop waiting for
 121  * somebody to say that they'd like to reschedule)
 122  */
 123 void cpu_idle(void)
 124 {
 125         /* endless idle loop with no priority at all */
 126         while (1) {
 127                 idle();
 128                 preempt_enable_no_resched();
 129                 schedule();
 130                 preempt_disable();
 131         }
 132 }
 133
 134 void machine_restart(char *__unused)
 135 {
 136 #if defined(CONFIG_BLKFIN_CACHE)
 137         bfin_write_IMEM_CONTROL(0x01);
 138         SSYNC();
 139 #endif
 140         bfin_reset();
 141         /* Dont do anything till the reset occurs */
 142         while (1) {
 143                 SSYNC();
 144         }
 145 }
 146
 147 void machine_halt(void)
 148 {
 149         for (;;)
 150                 asm volatile ("idle");
 151 }
 152
 153 void machine_power_off(void)
 154 {
 155         for (;;)
 156                 asm volatile ("idle");
 157 }
 158
 159 void show_regs(struct pt_regs *regs)
 160 {
 161         printk(KERN_NOTICE "\n");
 162         printk(KERN_NOTICE
 163                "PC: %08lu  Status: %04lu  SysStatus: %04lu  RETS: %08lu\n",
 164                regs->pc, regs->astat, regs->seqstat, regs->rets);
 165         printk(KERN_NOTICE
 166                "A0.x: %08lx  A0.w: %08lx  A1.x: %08lx  A1.w: %08lx\n",
 167                regs->a0x, regs->a0w, regs->a1x, regs->a1w);
 168         printk(KERN_NOTICE "P0: %08lx  P1: %08lx  P2: %08lx  P3: %08lx\n",
 169                regs->p0, regs->p1, regs->p2, regs->p3);
 170         printk(KERN_NOTICE "P4: %08lx  P5: %08lx\n", regs->p4, regs->p5);
 171         printk(KERN_NOTICE "R0: %08lx  R1: %08lx  R2: %08lx  R3: %08lx\n",
 172                regs->r0, regs->r1, regs->r2, regs->r3);
 173         printk(KERN_NOTICE "R4: %08lx  R5: %08lx  R6: %08lx  R7: %08lx\n",
 174                regs->r4, regs->r5, regs->r6, regs->r7);
 175
 176         if (!(regs->ipend))
 177                 printk("USP: %08lx\n", rdusp());
 178 }
 179
 180 /* Fill in the fpu structure for a core dump.  */
 181
 182 int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
 183 {
 184         return 1;
 185 }
 186
 187 /*
 188  * This gets run with P1 containing the
 189  * function to call, and R1 containing
 190  * the "args".  Note P0 is clobbered on the way here.
 191  */
 192 void kernel_thread_helper(void);
 193 __asm__(".section .text\n"
 194         ".align 4\n"
 195         "_kernel_thread_helper:\n\t"
 196         "\tsp += -12;\n\t"
 197         "\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
 198
 199 /*
 200  * Create a kernel thread.
 201  */
 202 pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
 203 {
 204         struct pt_regs regs;
 205
 206         memset(&regs, 0, sizeof(regs));
 207
 208         regs.r1 = (unsigned long)arg;
 209         regs.p1 = (unsigned long)fn;
 210         regs.pc = (unsigned long)kernel_thread_helper;
 211         regs.orig_p0 = -1;
 212         /* Set bit 2 to tell ret_from_fork we should be returning to kernel
 213            mode.  */
 214         regs.ipend = 0x8002;
 215         __asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
 216         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
 217                        NULL);
 218 }
 219
 220 void flush_thread(void)
 221 {
 222 }
 223
 224 asmlinkage int bfin_vfork(struct pt_regs *regs)
 225 {
 226         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
 227                        NULL);
 228 }
 229
 230 asmlinkage int bfin_clone(struct pt_regs *regs)
 231 {
 232         unsigned long clone_flags;
 233         unsigned long newsp;
 234
 235         /* syscall2 puts clone_flags in r0 and usp in r1 */
 236         clone_flags = regs->r0;
 237         newsp = regs->r1;
 238         if (!newsp)
 239                 newsp = rdusp();
 240         else
 241                 newsp -= 12;
 242         return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
 243 }
 244
 245 int
 246 copy_thread(int nr, unsigned long clone_flags,
 247             unsigned long usp, unsigned long topstk,
 248             struct task_struct *p, struct pt_regs *regs)
 249 {
 250         struct pt_regs *childregs;
 251
 252         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 253         *childregs = *regs;
 254         childregs->r0 = 0;
 255
 256         p->thread.usp = usp;
 257         p->thread.ksp = (unsigned long)childregs;
 258         p->thread.pc = (unsigned long)ret_from_fork;
 259
 260         return 0;
 261 }
 262
 263 /*
 264  * fill in the user structure for a core dump..
 265  */
 266 void dump_thread(struct pt_regs *regs, struct user *dump)
 267 {
 268         dump->magic = CMAGIC;
 269         dump->start_code = 0;
 270         dump->start_stack = rdusp() & ~(PAGE_SIZE - 1);
 271         dump->u_tsize = ((unsigned long)current->mm->end_code) >> PAGE_SHIFT;
 272         dump->u_dsize = ((unsigned long)(current->mm->brk +
 273                                          (PAGE_SIZE - 1))) >> PAGE_SHIFT;
 274         dump->u_dsize -= dump->u_tsize;
 275         dump->u_ssize = 0;
 276
 277         if (dump->start_stack < TASK_SIZE)
 278                 dump->u_ssize =
 279                     ((unsigned long)(TASK_SIZE -
 280                                      dump->start_stack)) >> PAGE_SHIFT;
 281
 282         dump->u_ar0 = (struct user_regs_struct *)((int)&dump->regs - (int)dump);
 283
 284         dump->regs.r0 = regs->r0;
 285         dump->regs.r1 = regs->r1;
 286         dump->regs.r2 = regs->r2;
 287         dump->regs.r3 = regs->r3;
 288         dump->regs.r4 = regs->r4;
 289         dump->regs.r5 = regs->r5;
 290         dump->regs.r6 = regs->r6;
 291         dump->regs.r7 = regs->r7;
 292         dump->regs.p0 = regs->p0;
 293         dump->regs.p1 = regs->p1;
 294         dump->regs.p2 = regs->p2;
 295         dump->regs.p3 = regs->p3;
 296         dump->regs.p4 = regs->p4;
 297         dump->regs.p5 = regs->p5;
 298         dump->regs.orig_p0 = regs->orig_p0;
 299         dump->regs.a0w = regs->a0w;
 300         dump->regs.a1w = regs->a1w;
 301         dump->regs.a0x = regs->a0x;
 302         dump->regs.a1x = regs->a1x;
 303         dump->regs.rets = regs->rets;
 304         dump->regs.astat = regs->astat;
 305         dump->regs.pc = regs->pc;
 306 }
 307
 308 /*
 309  * sys_execve() executes a new program.
 310  */
 311
 312 asmlinkage int sys_execve(char *name, char **argv, char **envp)
 313 {
 314         int error;
 315         char *filename;
 316         struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
 317
 318         lock_kernel();
 319         filename = getname(name);
 320         error = PTR_ERR(filename);
 321         if (IS_ERR(filename))
 322                 goto out;
 323         error = do_execve(filename, argv, envp, regs);
 324         putname(filename);
 325       out:
 326         unlock_kernel();
 327         return error;
 328 }
 329
 330 unsigned long get_wchan(struct task_struct *p)
 331 {
 332         unsigned long fp, pc;
 333         unsigned long stack_page;
 334         int count = 0;
 335         if (!p || p == current || p->state == TASK_RUNNING)
 336                 return 0;
 337
 338         stack_page = (unsigned long)p;
 339         fp = p->thread.usp;
 340         do {
 341                 if (fp < stack_page + sizeof(struct thread_info) ||
 342                     fp >= 8184 + stack_page)
 343                         return 0;
 344                 pc = ((unsigned long *)fp)[1];
 345                 if (!in_sched_functions(pc))
 346                         return pc;
 347                 fp = *(unsigned long *)fp;
 348         }
 349         while (count++ < 16);
 350         return 0;
 351 }
 352
 353 #if defined(CONFIG_ACCESS_CHECK)
 354 int _access_ok(unsigned long addr, unsigned long size)
 355 {
 356
 357         if (addr > (addr + size))
 358                 return 0;
 359         if (segment_eq(get_fs(),KERNEL_DS))
 360                 return 1;
 361 #ifdef CONFIG_MTD_UCLINUX
 362         if (addr >= memory_start && (addr + size) <= memory_end)
 363                 return 1;
 364         if (addr >= memory_mtd_end && (addr + size) <= physical_mem_end)
 365                 return 1;
 366 #else
 367         if (addr >= memory_start && (addr + size) <= physical_mem_end)
 368                 return 1;
 369 #endif
 370         if (addr >= (unsigned long)__init_begin &&
 371             addr + size <= (unsigned long)__init_end)
 372                 return 1;
 373         if (addr >= L1_SCRATCH_START
 374             && addr + size <= L1_SCRATCH_START + L1_SCRATCH_LENGTH)
 375                 return 1;
 376 #if L1_CODE_LENGTH != 0
 377         if (addr >= L1_CODE_START + (_etext_l1 - _stext_l1)
 378             && addr + size <= L1_CODE_START + L1_CODE_LENGTH)
 379                 return 1;
 380 #endif
 381 #if L1_DATA_A_LENGTH != 0
 382         if (addr >= L1_DATA_A_START + (_ebss_l1 - _sdata_l1)
 383             && addr + size <= L1_DATA_A_START + L1_DATA_A_LENGTH)
 384                 return 1;
 385 #endif
 386 #if L1_DATA_B_LENGTH != 0
 387         if (addr >= L1_DATA_B_START
 388             && addr + size <= L1_DATA_B_START + L1_DATA_B_LENGTH)
 389                 return 1;
 390 #endif
 391         return 0;
 392 }
 393 EXPORT_SYMBOL(_access_ok);
 394 #endif /* CONFIG_ACCESS_CHECK */