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         pr_info(" pt_regs @ %p\n", regs);
 133         pr_info(" SaveMask = 0x%04hx\n", regs->ctx.SaveMask);
 134         pr_info(" Flags = 0x%04hx (%c%c%c%c)\n", regs->ctx.Flags,
 135                 regs->ctx.Flags & FLAG_Z ? 'Z' : 'z',
 136                 regs->ctx.Flags & FLAG_N ? 'N' : 'n',
 137                 regs->ctx.Flags & FLAG_O ? 'O' : 'o',
 138                 regs->ctx.Flags & FLAG_C ? 'C' : 'c');
 139         pr_info(" TXRPT = 0x%08x\n", regs->ctx.CurrRPT);
 140         pr_info(" PC = 0x%08x\n", regs->ctx.CurrPC);
 141
 142         /* AX regs */
 143         for (i = 0; i < 2; i++) {
 144                 pr_info(" %s = 0x%08x    ",
 145                         AX0_names[i],
 146                         regs->ctx.AX[i].U0);
 147                 printk(" %s = 0x%08x\n",
 148                         AX1_names[i],
 149                         regs->ctx.AX[i].U1);
 150         }
 151
 152         if (regs->ctx.SaveMask & TBICTX_XEXT_BIT)
 153                 pr_warn(" Extended state present - AX2.[01] will be WRONG\n");
 154
 155         /* Special place with AXx.2 */
 156         pr_info(" A0.2  = 0x%08x    ",
 157                 regs->ctx.Ext.AX2.U0);
 158         printk(" A1.2  = 0x%08x\n",
 159                 regs->ctx.Ext.AX2.U1);
 160
 161         /* 'extended' AX regs (nominally, just AXx.3) */
 162         for (i = 0; i < (TBICTX_AX_REGS - 3); i++) {
 163                 pr_info(" A0.%d  = 0x%08x    ", i + 3, regs->ctx.AX3[i].U0);
 164                 printk(" A1.%d  = 0x%08x\n", i + 3, regs->ctx.AX3[i].U1);
 165         }
 166
 167         for (i = 0; i < 8; i++) {
 168                 pr_info(" %s = 0x%08x    ", DX0_names[i], regs->ctx.DX[i].U0);
 169                 printk(" %s = 0x%08x\n", DX1_names[i], regs->ctx.DX[i].U1);
 170         }
 171
 172         show_trace(NULL, (unsigned long *)regs->ctx.AX[0].U0, regs);
 173 }
 174
 175 int copy_thread(unsigned long clone_flags, unsigned long usp,
 176                 unsigned long arg, struct task_struct *tsk)
 177 {
 178         struct pt_regs *childregs = task_pt_regs(tsk);
 179         void *kernel_context = ((void *) childregs +
 180                                 sizeof(struct pt_regs));
 181         unsigned long global_base;
 182
 183         BUG_ON(((unsigned long)childregs) & 0x7);
 184         BUG_ON(((unsigned long)kernel_context) & 0x7);
 185
 186         memset(&tsk->thread.kernel_context, 0,
 187                         sizeof(tsk->thread.kernel_context));
 188
 189         tsk->thread.kernel_context = __TBISwitchInit(kernel_context,
 190                                                      ret_from_fork,
 191                                                      0, 0);
 192
 193         if (unlikely(tsk->flags & PF_KTHREAD)) {
 194                 /*
 195                  * Make sure we don't leak any kernel data to child's regs
 196                  * if kernel thread becomes a userspace thread in the future
 197                  */
 198                 memset(childregs, 0 , sizeof(struct pt_regs));
 199
 200                 global_base = __core_reg_get(A1GbP);
 201                 childregs->ctx.AX[0].U1 = (unsigned long) global_base;
 202                 childregs->ctx.AX[0].U0 = (unsigned long) kernel_context;
 203                 /* Set D1Ar1=arg and D1RtP=usp (fn) */
 204                 childregs->ctx.DX[4].U1 = usp;
 205                 childregs->ctx.DX[3].U1 = arg;
 206                 tsk->thread.int_depth = 2;
 207                 return 0;
 208         }
 209         /*
 210          * Get a pointer to where the new child's register block should have
 211          * been pushed.
 212          * The Meta's stack grows upwards, and the context is the the first
 213          * thing to be pushed by TBX (phew)
 214          */
 215         *childregs = *current_pt_regs();
 216         /* Set the correct stack for the clone mode */
 217         if (usp)
 218                 childregs->ctx.AX[0].U0 = ALIGN(usp, 8);
 219         tsk->thread.int_depth = 1;
 220
 221         /* set return value for child process */
 222         childregs->ctx.DX[0].U0 = 0;
 223
 224         /* The TLS pointer is passed as an argument to sys_clone. */
 225         if (clone_flags & CLONE_SETTLS)
 226                 tsk->thread.tls_ptr =
 227                                 (__force void __user *)childregs->ctx.DX[1].U1;
 228
 229 #ifdef CONFIG_METAG_FPU
 230         if (tsk->thread.fpu_context) {
 231                 struct meta_fpu_context *ctx;
 232
 233                 ctx = kmemdup(tsk->thread.fpu_context,
 234                               sizeof(struct meta_fpu_context), GFP_ATOMIC);
 235                 tsk->thread.fpu_context = ctx;
 236         }
 237 #endif
 238
 239 #ifdef CONFIG_METAG_DSP
 240         if (tsk->thread.dsp_context) {
 241                 struct meta_ext_context *ctx;
 242                 int i;
 243
 244                 ctx = kmemdup(tsk->thread.dsp_context,
 245                               sizeof(struct meta_ext_context), GFP_ATOMIC);
 246                 for (i = 0; i < 2; i++)
 247                         ctx->ram[i] = kmemdup(ctx->ram[i], ctx->ram_sz[i],
 248                                               GFP_ATOMIC);
 249                 tsk->thread.dsp_context = ctx;
 250         }
 251 #endif
 252
 253         return 0;
 254 }
 255
 256 #ifdef CONFIG_METAG_FPU
 257 static void alloc_fpu_context(struct thread_struct *thread)
 258 {
 259         thread->fpu_context = kzalloc(sizeof(struct meta_fpu_context),
 260                                       GFP_ATOMIC);
 261 }
 262
 263 static void clear_fpu(struct thread_struct *thread)
 264 {
 265         thread->user_flags &= ~TBICTX_FPAC_BIT;
 266         kfree(thread->fpu_context);
 267         thread->fpu_context = NULL;
 268 }
 269 #else
 270 static void clear_fpu(struct thread_struct *thread)
 271 {
 272 }
 273 #endif
 274
 275 #ifdef CONFIG_METAG_DSP
 276 static void clear_dsp(struct thread_struct *thread)
 277 {
 278         if (thread->dsp_context) {
 279                 kfree(thread->dsp_context->ram[0]);
 280                 kfree(thread->dsp_context->ram[1]);
 281
 282                 kfree(thread->dsp_context);
 283
 284                 thread->dsp_context = NULL;
 285         }
 286
 287         __core_reg_set(D0.8, 0);
 288 }
 289 #else
 290 static void clear_dsp(struct thread_struct *thread)
 291 {
 292 }
 293 #endif
 294
 295 struct task_struct *__sched __switch_to(struct task_struct *prev,
 296                                         struct task_struct *next)
 297 {
 298         TBIRES to, from;
 299
 300         to.Switch.pCtx = next->thread.kernel_context;
 301         to.Switch.pPara = prev;
 302
 303 #ifdef CONFIG_METAG_FPU
 304         if (prev->thread.user_flags & TBICTX_FPAC_BIT) {
 305                 struct pt_regs *regs = task_pt_regs(prev);
 306                 TBIRES state;
 307
 308                 state.Sig.SaveMask = prev->thread.user_flags;
 309                 state.Sig.pCtx = &regs->ctx;
 310
 311                 if (!prev->thread.fpu_context)
 312                         alloc_fpu_context(&prev->thread);
 313                 if (prev->thread.fpu_context)
 314                         __TBICtxFPUSave(state, prev->thread.fpu_context);
 315         }
 316         /*
 317          * Force a restore of the FPU context next time this process is
 318          * scheduled.
 319          */
 320         if (prev->thread.fpu_context)
 321                 prev->thread.fpu_context->needs_restore = true;
 322 #endif
 323
 324
 325         from = __TBISwitch(to, &prev->thread.kernel_context);
 326
 327         /* Restore TLS pointer for this process. */
 328         set_gateway_tls(current->thread.tls_ptr);
 329
 330         return (struct task_struct *) from.Switch.pPara;
 331 }
 332
 333 void flush_thread(void)
 334 {
 335         clear_fpu(&current->thread);
 336         clear_dsp(&current->thread);
 337 }
 338
 339 /*
 340  * Free current thread data structures etc.
 341  */
 342 void exit_thread(void)
 343 {
 344         clear_fpu(&current->thread);
 345         clear_dsp(&current->thread);
 346 }
 347
 348 /* TODO: figure out how to unwind the kernel stack here to figure out
 349  * where we went to sleep. */
 350 unsigned long get_wchan(struct task_struct *p)
 351 {
 352         return 0;
 353 }
 354
 355 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 356 {
 357         /* Returning 0 indicates that the FPU state was not stored (as it was
 358          * not in use) */
 359         return 0;
 360 }
 361
 362 #ifdef CONFIG_METAG_USER_TCM
 363
 364 #define ELF_MIN_ALIGN   PAGE_SIZE
 365
 366 #define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
 367 #define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
 368 #define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
 369
 370 #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
 371
 372 unsigned long __metag_elf_map(struct file *filep, unsigned long addr,
 373                               struct elf_phdr *eppnt, int prot, int type,
 374                               unsigned long total_size)
 375 {
 376         unsigned long map_addr, size;
 377         unsigned long page_off = ELF_PAGEOFFSET(eppnt->p_vaddr);
 378         unsigned long raw_size = eppnt->p_filesz + page_off;
 379         unsigned long off = eppnt->p_offset - page_off;
 380         unsigned int tcm_tag;
 381         addr = ELF_PAGESTART(addr);
 382         size = ELF_PAGEALIGN(raw_size);
 383
 384         /* mmap() will return -EINVAL if given a zero size, but a
 385          * segment with zero filesize is perfectly valid */
 386         if (!size)
 387                 return addr;
 388
 389         tcm_tag = tcm_lookup_tag(addr);
 390
 391         if (tcm_tag != TCM_INVALID_TAG)
 392                 type &= ~MAP_FIXED;
 393
 394         /*
 395         * total_size is the size of the ELF (interpreter) image.
 396         * The _first_ mmap needs to know the full size, otherwise
 397         * randomization might put this image into an overlapping
 398         * position with the ELF binary image. (since size < total_size)
 399         * So we first map the 'big' image - and unmap the remainder at
 400         * the end. (which unmap is needed for ELF images with holes.)
 401         */
 402         if (total_size) {
 403                 total_size = ELF_PAGEALIGN(total_size);
 404                 map_addr = vm_mmap(filep, addr, total_size, prot, type, off);
 405                 if (!BAD_ADDR(map_addr))
 406                         vm_munmap(map_addr+size, total_size-size);
 407         } else
 408                 map_addr = vm_mmap(filep, addr, size, prot, type, off);
 409
 410         if (!BAD_ADDR(map_addr) && tcm_tag != TCM_INVALID_TAG) {
 411                 struct tcm_allocation *tcm;
 412                 unsigned long tcm_addr;
 413
 414                 tcm = kmalloc(sizeof(*tcm), GFP_KERNEL);
 415                 if (!tcm)
 416                         return -ENOMEM;
 417
 418                 tcm_addr = tcm_alloc(tcm_tag, raw_size);
 419                 if (tcm_addr != addr) {
 420                         kfree(tcm);
 421                         return -ENOMEM;
 422                 }
 423
 424                 tcm->tag = tcm_tag;
 425                 tcm->addr = tcm_addr;
 426                 tcm->size = raw_size;
 427
 428                 list_add(&tcm->list, &current->mm->context.tcm);
 429
 430                 eppnt->p_vaddr = map_addr;
 431                 if (copy_from_user((void *) addr, (void __user *) map_addr,
 432                                    raw_size))
 433                         return -EFAULT;
 434         }
 435
 436         return map_addr;
 437 }
 438 #endif