LXR linux/arch/blackfin/kernel/process.c

   1/*
   2 * Blackfin architecture-dependent process handling
   3 *
   4 * Copyright 2004-2009 Analog Devices Inc.
   5 *
   6 * Licensed under the GPL-2 or later
   7 */
   8
   9#include <linux/module.h>
  10#include <linux/smp_lock.h>
  11#include <linux/unistd.h>
  12#include <linux/user.h>
  13#include <linux/uaccess.h>
  14#include <linux/sched.h>
  15#include <linux/tick.h>
  16#include <linux/fs.h>
  17#include <linux/err.h>
  18
  19#include <asm/blackfin.h>
  20#include <asm/fixed_code.h>
  21#include <asm/mem_map.h>
  22
  23asmlinkage void ret_from_fork(void);
  24
  25/* Points to the SDRAM backup memory for the stack that is currently in
  26 * L1 scratchpad memory.
  27 */
  28void *current_l1_stack_save;
  29
  30/* The number of tasks currently using a L1 stack area.  The SRAM is
  31 * allocated/deallocated whenever this changes from/to zero.
  32 */
  33int nr_l1stack_tasks;
  34
  35/* Start and length of the area in L1 scratchpad memory which we've allocated
  36 * for process stacks.
  37 */
  38void *l1_stack_base;
  39unsigned long l1_stack_len;
  40
  41/*
  42 * Powermanagement idle function, if any..
  43 */
  44void (*pm_idle)(void) = NULL;
  45EXPORT_SYMBOL(pm_idle);
  46
  47void (*pm_power_off)(void) = NULL;
  48EXPORT_SYMBOL(pm_power_off);
  49
  50/*
  51 * The idle loop on BFIN
  52 */
  53#ifdef CONFIG_IDLE_L1
  54static void default_idle(void)__attribute__((l1_text));
  55void cpu_idle(void)__attribute__((l1_text));
  56#endif
  57
  58/*
  59 * This is our default idle handler.  We need to disable
  60 * interrupts here to ensure we don't miss a wakeup call.
  61 */
  62static void default_idle(void)
  63{
  64#ifdef CONFIG_IPIPE
  65        ipipe_suspend_domain();
  66#endif
  67        local_irq_disable_hw();
  68        if (!need_resched())
  69                idle_with_irq_disabled();
  70
  71        local_irq_enable_hw();
  72}
  73
  74/*
  75 * The idle thread.  We try to conserve power, while trying to keep
  76 * overall latency low.  The architecture specific idle is passed
  77 * a value to indicate the level of "idleness" of the system.
  78 */
  79void cpu_idle(void)
  80{
  81        /* endless idle loop with no priority at all */
  82        while (1) {
  83                void (*idle)(void) = pm_idle;
  84
  85#ifdef CONFIG_HOTPLUG_CPU
  86                if (cpu_is_offline(smp_processor_id()))
  87                        cpu_die();
  88#endif
  89                if (!idle)
  90                        idle = default_idle;
  91                tick_nohz_stop_sched_tick(1);
  92                while (!need_resched())
  93                        idle();
  94                tick_nohz_restart_sched_tick();
  95                preempt_enable_no_resched();
  96                schedule();
  97                preempt_disable();
  98        }
  99}
 100
 101/* Fill in the fpu structure for a core dump.  */
 102
 103int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
 104{
 105        return 1;
 106}
 107
 108/*
 109 * This gets run with P1 containing the
 110 * function to call, and R1 containing
 111 * the "args".  Note P0 is clobbered on the way here.
 112 */
 113void kernel_thread_helper(void);
 114__asm__(".section .text\n"
 115        ".align 4\n"
 116        "_kernel_thread_helper:\n\t"
 117        "\tsp += -12;\n\t"
 118        "\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
 119
 120/*
 121 * Create a kernel thread.
 122 */
 123pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
 124{
 125        struct pt_regs regs;
 126
 127        memset(&regs, 0, sizeof(regs));
 128
 129        regs.r1 = (unsigned long)arg;
 130        regs.p1 = (unsigned long)fn;
 131        regs.pc = (unsigned long)kernel_thread_helper;
 132        regs.orig_p0 = -1;
 133        /* Set bit 2 to tell ret_from_fork we should be returning to kernel
 134           mode.  */
 135        regs.ipend = 0x8002;
 136        __asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
 137        return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
 138                       NULL);
 139}
 140EXPORT_SYMBOL(kernel_thread);
 141
 142/*
 143 * Do necessary setup to start up a newly executed thread.
 144 *
 145 * pass the data segment into user programs if it exists,
 146 * it can't hurt anything as far as I can tell
 147 */
 148void start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 149{
 150        set_fs(USER_DS);
 151        regs->pc = new_ip;
 152        if (current->mm)
 153                regs->p5 = current->mm->start_data;
 154#ifndef CONFIG_SMP
 155        task_thread_info(current)->l1_task_info.stack_start =
 156                (void *)current->mm->context.stack_start;
 157        task_thread_info(current)->l1_task_info.lowest_sp = (void *)new_sp;
 158        memcpy(L1_SCRATCH_TASK_INFO, &task_thread_info(current)->l1_task_info,
 159               sizeof(*L1_SCRATCH_TASK_INFO));
 160#endif
 161        wrusp(new_sp);
 162}
 163EXPORT_SYMBOL_GPL(start_thread);
 164
 165void flush_thread(void)
 166{
 167}
 168
 169asmlinkage int bfin_vfork(struct pt_regs *regs)
 170{
 171        return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
 172                       NULL);
 173}
 174
 175asmlinkage int bfin_clone(struct pt_regs *regs)
 176{
 177        unsigned long clone_flags;
 178        unsigned long newsp;
 179
 180#ifdef __ARCH_SYNC_CORE_DCACHE
 181        if (current->rt.nr_cpus_allowed == num_possible_cpus()) {
 182                current->cpus_allowed = cpumask_of_cpu(smp_processor_id());
 183                current->rt.nr_cpus_allowed = 1;
 184        }
 185#endif
 186
 187        /* syscall2 puts clone_flags in r0 and usp in r1 */
 188        clone_flags = regs->r0;
 189        newsp = regs->r1;
 190        if (!newsp)
 191                newsp = rdusp();
 192        else
 193                newsp -= 12;
 194        return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
 195}
 196
 197int
 198copy_thread(unsigned long clone_flags,
 199            unsigned long usp, unsigned long topstk,
 200            struct task_struct *p, struct pt_regs *regs)
 201{
 202        struct pt_regs *childregs;
 203
 204        childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 205        *childregs = *regs;
 206        childregs->r0 = 0;
 207
 208        p->thread.usp = usp;
 209        p->thread.ksp = (unsigned long)childregs;
 210        p->thread.pc = (unsigned long)ret_from_fork;
 211
 212        return 0;
 213}
 214
 215/*
 216 * sys_execve() executes a new program.
 217 */
 218
 219asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
 220{
 221        int error;
 222        char *filename;
 223        struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
 224
 225        lock_kernel();
 226        filename = getname(name);
 227        error = PTR_ERR(filename);
 228        if (IS_ERR(filename))
 229                goto out;
 230        error = do_execve(filename, argv, envp, regs);
 231        putname(filename);
 232 out:
 233        unlock_kernel();
 234        return error;
 235}
 236
 237unsigned long get_wchan(struct task_struct *p)
 238{
 239        unsigned long fp, pc;
 240        unsigned long stack_page;
 241        int count = 0;
 242        if (!p || p == current || p->state == TASK_RUNNING)
 243                return 0;
 244
 245        stack_page = (unsigned long)p;
 246        fp = p->thread.usp;
 247        do {
 248                if (fp < stack_page + sizeof(struct thread_info) ||
 249                    fp >= 8184 + stack_page)
 250                        return 0;
 251                pc = ((unsigned long *)fp)[1];
 252                if (!in_sched_functions(pc))
 253                        return pc;
 254                fp = *(unsigned long *)fp;
 255        }
 256        while (count++ < 16);
 257        return 0;
 258}
 259
 260void finish_atomic_sections (struct pt_regs *regs)
 261{
 262        int __user *up0 = (int __user *)regs->p0;
 263
 264        switch (regs->pc) {
 265        case ATOMIC_XCHG32 + 2:
 266                put_user(regs->r1, up0);
 267                regs->pc = ATOMIC_XCHG32 + 4;
 268                break;
 269
 270        case ATOMIC_CAS32 + 2:
 271        case ATOMIC_CAS32 + 4:
 272                if (regs->r0 == regs->r1)
 273        case ATOMIC_CAS32 + 6:
 274                        put_user(regs->r2, up0);
 275                regs->pc = ATOMIC_CAS32 + 8;
 276                break;
 277
 278        case ATOMIC_ADD32 + 2:
 279                regs->r0 = regs->r1 + regs->r0;
 280                /* fall through */
 281        case ATOMIC_ADD32 + 4:
 282                put_user(regs->r0, up0);
 283                regs->pc = ATOMIC_ADD32 + 6;
 284                break;
 285
 286        case ATOMIC_SUB32 + 2:
 287                regs->r0 = regs->r1 - regs->r0;
 288                /* fall through */
 289        case ATOMIC_SUB32 + 4:
 290                put_user(regs->r0, up0);
 291                regs->pc = ATOMIC_SUB32 + 6;
 292                break;
 293
 294        case ATOMIC_IOR32 + 2:
 295                regs->r0 = regs->r1 | regs->r0;
 296                /* fall through */
 297        case ATOMIC_IOR32 + 4:
 298                put_user(regs->r0, up0);
 299                regs->pc = ATOMIC_IOR32 + 6;
 300                break;
 301
 302        case ATOMIC_AND32 + 2:
 303                regs->r0 = regs->r1 & regs->r0;
 304                /* fall through */
 305        case ATOMIC_AND32 + 4:
 306                put_user(regs->r0, up0);
 307                regs->pc = ATOMIC_AND32 + 6;
 308                break;
 309
 310        case ATOMIC_XOR32 + 2:
 311                regs->r0 = regs->r1 ^ regs->r0;
 312                /* fall through */
 313        case ATOMIC_XOR32 + 4:
 314                put_user(regs->r0, up0);
 315                regs->pc = ATOMIC_XOR32 + 6;
 316                break;
 317        }
 318}
 319
 320static inline
 321int in_mem(unsigned long addr, unsigned long size,
 322           unsigned long start, unsigned long end)
 323{
 324        return addr >= start && addr + size <= end;
 325}
 326static inline
 327int in_mem_const_off(unsigned long addr, unsigned long size, unsigned long off,
 328                     unsigned long const_addr, unsigned long const_size)
 329{
 330        return const_size &&
 331               in_mem(addr, size, const_addr + off, const_addr + const_size);
 332}
 333static inline
 334int in_mem_const(unsigned long addr, unsigned long size,
 335                 unsigned long const_addr, unsigned long const_size)
 336{
 337        return in_mem_const_off(addr, size, 0, const_addr, const_size);
 338}
 339#define IN_ASYNC(bnum, bctlnum) \
 340({ \
 341        (bfin_read_EBIU_AMGCTL() & 0xe) < ((bnum + 1) << 1) ? -EFAULT : \
 342        bfin_read_EBIU_AMBCTL##bctlnum() & B##bnum##RDYEN ? -EFAULT : \
 343        BFIN_MEM_ACCESS_CORE; \
 344})
 345
 346int bfin_mem_access_type(unsigned long addr, unsigned long size)
 347{
 348        int cpu = raw_smp_processor_id();
 349
 350        /* Check that things do not wrap around */
 351        if (addr > ULONG_MAX - size)
 352                return -EFAULT;
 353
 354        if (in_mem(addr, size, FIXED_CODE_START, physical_mem_end))
 355                return BFIN_MEM_ACCESS_CORE;
 356
 357        if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
 358                return cpu == 0 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
 359        if (in_mem_const(addr, size, L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 360                return cpu == 0 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
 361        if (in_mem_const(addr, size, L1_DATA_A_START, L1_DATA_A_LENGTH))
 362                return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 363        if (in_mem_const(addr, size, L1_DATA_B_START, L1_DATA_B_LENGTH))
 364                return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 365#ifdef COREB_L1_CODE_START
 366        if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
 367                return cpu == 1 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
 368        if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 369                return cpu == 1 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
 370        if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
 371                return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 372        if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
 373                return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 374#endif
 375        if (in_mem_const(addr, size, L2_START, L2_LENGTH))
 376                return BFIN_MEM_ACCESS_CORE;
 377
 378        if (addr >= SYSMMR_BASE)
 379                return BFIN_MEM_ACCESS_CORE_ONLY;
 380
 381        /* We can't read EBIU banks that aren't enabled or we end up hanging
 382         * on the access to the async space.
 383         */
 384        if (in_mem_const(addr, size, ASYNC_BANK0_BASE, ASYNC_BANK0_SIZE))
 385                return IN_ASYNC(0, 0);
 386        if (in_mem_const(addr, size, ASYNC_BANK1_BASE, ASYNC_BANK1_SIZE))
 387                return IN_ASYNC(1, 0);
 388        if (in_mem_const(addr, size, ASYNC_BANK2_BASE, ASYNC_BANK2_SIZE))
 389                return IN_ASYNC(2, 1);
 390        if (in_mem_const(addr, size, ASYNC_BANK3_BASE, ASYNC_BANK3_SIZE))
 391                return IN_ASYNC(3, 1);
 392
 393        if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
 394                return BFIN_MEM_ACCESS_CORE;
 395        if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
 396                return BFIN_MEM_ACCESS_DMA;
 397
 398        return -EFAULT;
 399}
 400
 401#if defined(CONFIG_ACCESS_CHECK)
 402#ifdef CONFIG_ACCESS_OK_L1
 403__attribute__((l1_text))
 404#endif
 405/* Return 1 if access to memory range is OK, 0 otherwise */
 406int _access_ok(unsigned long addr, unsigned long size)
 407{
 408        if (size == 0)
 409                return 1;
 410        /* Check that things do not wrap around */
 411        if (addr > ULONG_MAX - size)
 412                return 0;
 413        if (segment_eq(get_fs(), KERNEL_DS))
 414                return 1;
 415#ifdef CONFIG_MTD_UCLINUX
 416        if (1)
 417#else
 418        if (0)
 419#endif
 420        {
 421                if (in_mem(addr, size, memory_start, memory_end))
 422                        return 1;
 423                if (in_mem(addr, size, memory_mtd_end, physical_mem_end))
 424                        return 1;
 425# ifndef CONFIG_ROMFS_ON_MTD
 426                if (0)
 427# endif
 428                        /* For XIP, allow user space to use pointers within the ROMFS.  */
 429                        if (in_mem(addr, size, memory_mtd_start, memory_mtd_end))
 430                                return 1;
 431        } else {
 432                if (in_mem(addr, size, memory_start, physical_mem_end))
 433                        return 1;
 434        }
 435
 436        if (in_mem(addr, size, (unsigned long)__init_begin, (unsigned long)__init_end))
 437                return 1;
 438
 439        if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
 440                return 1;
 441        if (in_mem_const_off(addr, size, _etext_l1 - _stext_l1, L1_CODE_START, L1_CODE_LENGTH))
 442                return 1;
 443        if (in_mem_const_off(addr, size, _ebss_l1 - _sdata_l1, L1_DATA_A_START, L1_DATA_A_LENGTH))
 444                return 1;
 445        if (in_mem_const_off(addr, size, _ebss_b_l1 - _sdata_b_l1, L1_DATA_B_START, L1_DATA_B_LENGTH))
 446                return 1;
 447#ifdef COREB_L1_CODE_START
 448        if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
 449                return 1;
 450        if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 451                return 1;
 452        if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
 453                return 1;
 454        if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
 455                return 1;
 456#endif
 457        if (in_mem_const_off(addr, size, _ebss_l2 - _stext_l2, L2_START, L2_LENGTH))
 458                return 1;
 459
 460        if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
 461                return 1;
 462        if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
 463                return 1;
 464
 465        return 0;
 466}
 467EXPORT_SYMBOL(_access_ok);
 468#endif /* CONFIG_ACCESS_CHECK */
 469