arch/metag/kernel/process.c

   1 /*
   2  * Copyright (C) 2005,2006,2007,2008,2009,2010,2011 Imagination Technologies
   3  *
   4  * This file contains the architecture-dependent parts of process handling.
   5  *
   6  */
   7
   8 #include <linux/errno.h>
   9 #include <linux/export.h>
  10 #include <linux/sched.h>
  11 #include <linux/kernel.h>
  12 #include <linux/mm.h>
  13 #include <linux/unistd.h>
  14 #include <linux/ptrace.h>
  15 #include <linux/user.h>
  16 #include <linux/reboot.h>
  17 #include <linux/elfcore.h>
  18 #include <linux/fs.h>
  19 #include <linux/tick.h>
  20 #include <linux/slab.h>
  21 #include <linux/mman.h>
  22 #include <linux/pm.h>
  23 #include <linux/syscalls.h>
  24 #include <linux/uaccess.h>
  25 #include <linux/smp.h>
  26 #include <asm/core_reg.h>
  27 #include <asm/user_gateway.h>
  28 #include <asm/tcm.h>
  29 #include <asm/traps.h>
  30 #include <asm/switch_to.h>
  31
  32 /*
  33  * Wait for the next interrupt and enable local interrupts
  34  */
  35 void arch_cpu_idle(void)
  36 {
  37         int tmp;
  38
  39         /*
  40          * Quickly jump straight into the interrupt entry point without actually
  41          * triggering an interrupt. When TXSTATI gets read the processor will
  42          * block until an interrupt is triggered.
  43          */
  44         asm volatile (/* Switch into ISTAT mode */
  45                       "RTH\n\t"
  46                       /* Enable local interrupts */
  47                       "MOV      TXMASKI, %1\n\t"
  48                       /*
  49                        * We can't directly "SWAP PC, PCX", so we swap via a
  50                        * temporary. Essentially we do:
  51                        *  PCX_new = 1f (the place to continue execution)
  52                        *  PC = PCX_old
  53                        */
  54                       "ADD      %0, CPC0, #(1f-.)\n\t"
  55                       "SWAP     PCX, %0\n\t"
  56                       "MOV      PC, %0\n"
  57                       /* Continue execution here with interrupts enabled */
  58                       "1:"
  59                       : "=a" (tmp)
  60                       : "r" (get_trigger_mask()));
  61 }
  62
  63 #ifdef CONFIG_HOTPLUG_CPU
  64 void arch_cpu_idle_dead(void)
  65 {
  66         cpu_die();
  67 }
  68 #endif
  69
  70 void (*pm_power_off)(void);
  71 EXPORT_SYMBOL(pm_power_off);
  72
  73 void (*soc_restart)(char *cmd);
  74 void (*soc_halt)(void);
  75
  76 void machine_restart(char *cmd)
  77 {
  78         if (soc_restart)
  79                 soc_restart(cmd);
  80         hard_processor_halt(HALT_OK);
  81 }
  82
  83 void machine_halt(void)
  84 {
  85         if (soc_halt)
  86                 soc_halt();
  87         smp_send_stop();
  88         hard_processor_halt(HALT_OK);
  89 }
  90
  91 void machine_power_off(void)
  92 {
  93         if (pm_power_off)
  94                 pm_power_off();
  95         smp_send_stop();
  96         hard_processor_halt(HALT_OK);
  97 }
  98
  99 #define FLAG_Z 0x8
 100 #define FLAG_N 0x4
 101 #define FLAG_O 0x2
 102 #define FLAG_C 0x1
 103
 104 void show_regs(struct pt_regs *regs)
 105 {
 106         int i;
 107         const char *AX0_names[] = {"A0StP", "A0FrP"};
 108         const char *AX1_names[] = {"A1GbP", "A1LbP"};
 109
 110         const char *DX0_names[] = {
 111                 "D0Re0",
 112                 "D0Ar6",
 113                 "D0Ar4",
 114                 "D0Ar2",
 115                 "D0FrT",
 116                 "D0.5 ",
 117                 "D0.6 ",
 118                 "D0.7 "
 119         };
 120
 121         const char *DX1_names[] = {
 122                 "D1Re0",
 123                 "D1Ar5",
 124                 "D1Ar3",
 125                 "D1Ar1",
 126                 "D1RtP",
 127                 "D1.5 ",
 128                 "D1.6 ",
 129                 "D1.7 "
 130         };
 131
 132         show_regs_print_info(KERN_INFO);
 133
 134         pr_info(" pt_regs @ %p\n", regs);
 135         pr_info(" SaveMask = 0x%04hx\n", regs->ctx.SaveMask);
 136         pr_info(" Flags = 0x%04hx (%c%c%c%c)\n", regs->ctx.Flags,
 137                 regs->ctx.Flags & FLAG_Z ? 'Z' : 'z',
 138                 regs->ctx.Flags & FLAG_N ? 'N' : 'n',
 139                 regs->ctx.Flags & FLAG_O ? 'O' : 'o',
 140                 regs->ctx.Flags & FLAG_C ? 'C' : 'c');
 141         pr_info(" TXRPT = 0x%08x\n", regs->ctx.CurrRPT);
 142         pr_info(" PC = 0x%08x\n", regs->ctx.CurrPC);
 143
 144         /* AX regs */
 145         for (i = 0; i < 2; i++) {
 146                 pr_info(" %s = 0x%08x    ",
 147                         AX0_names[i],
 148                         regs->ctx.AX[i].U0);
 149                 printk(" %s = 0x%08x\n",
 150                         AX1_names[i],
 151                         regs->ctx.AX[i].U1);
 152         }
 153
 154         if (regs->ctx.SaveMask & TBICTX_XEXT_BIT)
 155                 pr_warn(" Extended state present - AX2.[01] will be WRONG\n");
 156
 157         /* Special place with AXx.2 */
 158         pr_info(" A0.2  = 0x%08x    ",
 159                 regs->ctx.Ext.AX2.U0);
 160         printk(" A1.2  = 0x%08x\n",
 161                 regs->ctx.Ext.AX2.U1);
 162
 163         /* 'extended' AX regs (nominally, just AXx.3) */
 164         for (i = 0; i < (TBICTX_AX_REGS - 3); i++) {
 165                 pr_info(" A0.%d  = 0x%08x    ", i + 3, regs->ctx.AX3[i].U0);
 166                 printk(" A1.%d  = 0x%08x\n", i + 3, regs->ctx.AX3[i].U1);
 167         }
 168
 169         for (i = 0; i < 8; i++) {
 170                 pr_info(" %s = 0x%08x    ", DX0_names[i], regs->ctx.DX[i].U0);
 171                 printk(" %s = 0x%08x\n", DX1_names[i], regs->ctx.DX[i].U1);
 172         }
 173
 174         show_trace(NULL, (unsigned long *)regs->ctx.AX[0].U0, regs);
 175 }
 176
 177 int copy_thread(unsigned long clone_flags, unsigned long usp,
 178                 unsigned long arg, struct task_struct *tsk)
 179 {
 180         struct pt_regs *childregs = task_pt_regs(tsk);
 181         void *kernel_context = ((void *) childregs +
 182                                 sizeof(struct pt_regs));
 183         unsigned long global_base;
 184
 185         BUG_ON(((unsigned long)childregs) & 0x7);
 186         BUG_ON(((unsigned long)kernel_context) & 0x7);
 187
 188         memset(&tsk->thread.kernel_context, 0,
 189                         sizeof(tsk->thread.kernel_context));
 190
 191         tsk->thread.kernel_context = __TBISwitchInit(kernel_context,
 192                                                      ret_from_fork,
 193                                                      0, 0);
 194
 195         if (unlikely(tsk->flags & PF_KTHREAD)) {
 196                 /*
 197                  * Make sure we don't leak any kernel data to child's regs
 198                  * if kernel thread becomes a userspace thread in the future
 199                  */
 200                 memset(childregs, 0 , sizeof(struct pt_regs));
 201
 202                 global_base = __core_reg_get(A1GbP);
 203                 childregs->ctx.AX[0].U1 = (unsigned long) global_base;
 204                 childregs->ctx.AX[0].U0 = (unsigned long) kernel_context;
 205                 /* Set D1Ar1=arg and D1RtP=usp (fn) */
 206                 childregs->ctx.DX[4].U1 = usp;
 207                 childregs->ctx.DX[3].U1 = arg;
 208                 tsk->thread.int_depth = 2;
 209                 return 0;
 210         }
 211         /*
 212          * Get a pointer to where the new child's register block should have
 213          * been pushed.
 214          * The Meta's stack grows upwards, and the context is the the first
 215          * thing to be pushed by TBX (phew)
 216          */
 217         *childregs = *current_pt_regs();
 218         /* Set the correct stack for the clone mode */
 219         if (usp)
 220                 childregs->ctx.AX[0].U0 = ALIGN(usp, 8);
 221         tsk->thread.int_depth = 1;
 222
 223         /* set return value for child process */
 224         childregs->ctx.DX[0].U0 = 0;
 225
 226         /* The TLS pointer is passed as an argument to sys_clone. */
 227         if (clone_flags & CLONE_SETTLS)
 228                 tsk->thread.tls_ptr =
 229                                 (__force void __user *)childregs->ctx.DX[1].U1;
 230
 231 #ifdef CONFIG_METAG_FPU
 232         if (tsk->thread.fpu_context) {
 233                 struct meta_fpu_context *ctx;
 234
 235                 ctx = kmemdup(tsk->thread.fpu_context,
 236                               sizeof(struct meta_fpu_context), GFP_ATOMIC);
 237                 tsk->thread.fpu_context = ctx;
 238         }
 239 #endif
 240
 241 #ifdef CONFIG_METAG_DSP
 242         if (tsk->thread.dsp_context) {
 243                 struct meta_ext_context *ctx;
 244                 int i;
 245
 246                 ctx = kmemdup(tsk->thread.dsp_context,
 247                               sizeof(struct meta_ext_context), GFP_ATOMIC);
 248                 for (i = 0; i < 2; i++)
 249                         ctx->ram[i] = kmemdup(ctx->ram[i], ctx->ram_sz[i],
 250                                               GFP_ATOMIC);
 251                 tsk->thread.dsp_context = ctx;
 252         }
 253 #endif
 254
 255         return 0;
 256 }
 257
 258 #ifdef CONFIG_METAG_FPU
 259 static void alloc_fpu_context(struct thread_struct *thread)
 260 {
 261         thread->fpu_context = kzalloc(sizeof(struct meta_fpu_context),
 262                                       GFP_ATOMIC);
 263 }
 264
 265 static void clear_fpu(struct thread_struct *thread)
 266 {
 267         thread->user_flags &= ~TBICTX_FPAC_BIT;
 268         kfree(thread->fpu_context);
 269         thread->fpu_context = NULL;
 270 }
 271 #else
 272 static void clear_fpu(struct thread_struct *thread)
 273 {
 274 }
 275 #endif
 276
 277 #ifdef CONFIG_METAG_DSP
 278 static void clear_dsp(struct thread_struct *thread)
 279 {
 280         if (thread->dsp_context) {
 281                 kfree(thread->dsp_context->ram[0]);
 282                 kfree(thread->dsp_context->ram[1]);
 283
 284                 kfree(thread->dsp_context);
 285
 286                 thread->dsp_context = NULL;
 287         }
 288
 289         __core_reg_set(D0.8, 0);
 290 }
 291 #else
 292 static void clear_dsp(struct thread_struct *thread)
 293 {
 294 }
 295 #endif
 296
 297 struct task_struct *__sched __switch_to(struct task_struct *prev,
 298                                         struct task_struct *next)
 299 {
 300         TBIRES to, from;
 301
 302         to.Switch.pCtx = next->thread.kernel_context;
 303         to.Switch.pPara = prev;
 304
 305 #ifdef CONFIG_METAG_FPU
 306         if (prev->thread.user_flags & TBICTX_FPAC_BIT) {
 307                 struct pt_regs *regs = task_pt_regs(prev);
 308                 TBIRES state;
 309
 310                 state.Sig.SaveMask = prev->thread.user_flags;
 311                 state.Sig.pCtx = &regs->ctx;
 312
 313                 if (!prev->thread.fpu_context)
 314                         alloc_fpu_context(&prev->thread);
 315                 if (prev->thread.fpu_context)
 316                         __TBICtxFPUSave(state, prev->thread.fpu_context);
 317         }
 318         /*
 319          * Force a restore of the FPU context next time this process is
 320          * scheduled.
 321          */
 322         if (prev->thread.fpu_context)
 323                 prev->thread.fpu_context->needs_restore = true;
 324 #endif
 325
 326
 327         from = __TBISwitch(to, &prev->thread.kernel_context);
 328
 329         /* Restore TLS pointer for this process. */
 330         set_gateway_tls(current->thread.tls_ptr);
 331
 332         return (struct task_struct *) from.Switch.pPara;
 333 }
 334
 335 void flush_thread(void)
 336 {
 337         clear_fpu(&current->thread);
 338         clear_dsp(&current->thread);
 339 }
 340
 341 /*
 342  * Free current thread data structures etc.
 343  */
 344 void exit_thread(void)
 345 {
 346         clear_fpu(&current->thread);
 347         clear_dsp(&current->thread);
 348 }
 349
 350 /* TODO: figure out how to unwind the kernel stack here to figure out
 351  * where we went to sleep. */
 352 unsigned long get_wchan(struct task_struct *p)
 353 {
 354         return 0;
 355 }
 356
 357 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 358 {
 359         /* Returning 0 indicates that the FPU state was not stored (as it was
 360          * not in use) */
 361         return 0;
 362 }
 363
 364 #ifdef CONFIG_METAG_USER_TCM
 365
 366 #define ELF_MIN_ALIGN   PAGE_SIZE
 367
 368 #define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
 369 #define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
 370 #define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
 371
 372 #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
 373
 374 unsigned long __metag_elf_map(struct file *filep, unsigned long addr,
 375                               struct elf_phdr *eppnt, int prot, int type,
 376                               unsigned long total_size)
 377 {
 378         unsigned long map_addr, size;
 379         unsigned long page_off = ELF_PAGEOFFSET(eppnt->p_vaddr);
 380         unsigned long raw_size = eppnt->p_filesz + page_off;
 381         unsigned long off = eppnt->p_offset - page_off;
 382         unsigned int tcm_tag;
 383         addr = ELF_PAGESTART(addr);
 384         size = ELF_PAGEALIGN(raw_size);
 385
 386         /* mmap() will return -EINVAL if given a zero size, but a
 387          * segment with zero filesize is perfectly valid */
 388         if (!size)
 389                 return addr;
 390
 391         tcm_tag = tcm_lookup_tag(addr);
 392
 393         if (tcm_tag != TCM_INVALID_TAG)
 394                 type &= ~MAP_FIXED;
 395
 396         /*
 397         * total_size is the size of the ELF (interpreter) image.
 398         * The _first_ mmap needs to know the full size, otherwise
 399         * randomization might put this image into an overlapping
 400         * position with the ELF binary image. (since size < total_size)
 401         * So we first map the 'big' image - and unmap the remainder at
 402         * the end. (which unmap is needed for ELF images with holes.)
 403         */
 404         if (total_size) {
 405                 total_size = ELF_PAGEALIGN(total_size);
 406                 map_addr = vm_mmap(filep, addr, total_size, prot, type, off);
 407                 if (!BAD_ADDR(map_addr))
 408                         vm_munmap(map_addr+size, total_size-size);
 409         } else
 410                 map_addr = vm_mmap(filep, addr, size, prot, type, off);
 411
 412         if (!BAD_ADDR(map_addr) && tcm_tag != TCM_INVALID_TAG) {
 413                 struct tcm_allocation *tcm;
 414                 unsigned long tcm_addr;
 415
 416                 tcm = kmalloc(sizeof(*tcm), GFP_KERNEL);
 417                 if (!tcm)
 418                         return -ENOMEM;
 419
 420                 tcm_addr = tcm_alloc(tcm_tag, raw_size);
 421                 if (tcm_addr != addr) {
 422                         kfree(tcm);
 423                         return -ENOMEM;
 424                 }
 425
 426                 tcm->tag = tcm_tag;
 427                 tcm->addr = tcm_addr;
 428                 tcm->size = raw_size;
 429
 430                 list_add(&tcm->list, &current->mm->context.tcm);
 431
 432                 eppnt->p_vaddr = map_addr;
 433                 if (copy_from_user((void *) addr, (void __user *) map_addr,
 434                                    raw_size))
 435                         return -EFAULT;
 436         }
 437
 438         return map_addr;
 439 }
 440 #endif