kernel/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 /*
 178  * Copy architecture-specific thread state
 179  */
 180 int copy_thread(unsigned long clone_flags, unsigned long usp,
 181                 unsigned long kthread_arg, struct task_struct *tsk)
 182 {
 183         struct pt_regs *childregs = task_pt_regs(tsk);
 184         void *kernel_context = ((void *) childregs +
 185                                 sizeof(struct pt_regs));
 186         unsigned long global_base;
 187
 188         BUG_ON(((unsigned long)childregs) & 0x7);
 189         BUG_ON(((unsigned long)kernel_context) & 0x7);
 190
 191         memset(&tsk->thread.kernel_context, 0,
 192                         sizeof(tsk->thread.kernel_context));
 193
 194         tsk->thread.kernel_context = __TBISwitchInit(kernel_context,
 195                                                      ret_from_fork,
 196                                                      0, 0);
 197
 198         if (unlikely(tsk->flags & PF_KTHREAD)) {
 199                 /*
 200                  * Make sure we don't leak any kernel data to child's regs
 201                  * if kernel thread becomes a userspace thread in the future
 202                  */
 203                 memset(childregs, 0 , sizeof(struct pt_regs));
 204
 205                 global_base = __core_reg_get(A1GbP);
 206                 childregs->ctx.AX[0].U1 = (unsigned long) global_base;
 207                 childregs->ctx.AX[0].U0 = (unsigned long) kernel_context;
 208                 /* Set D1Ar1=kthread_arg and D1RtP=usp (fn) */
 209                 childregs->ctx.DX[4].U1 = usp;
 210                 childregs->ctx.DX[3].U1 = kthread_arg;
 211                 tsk->thread.int_depth = 2;
 212                 return 0;
 213         }
 214
 215         /*
 216          * Get a pointer to where the new child's register block should have
 217          * been pushed.
 218          * The Meta's stack grows upwards, and the context is the the first
 219          * thing to be pushed by TBX (phew)
 220          */
 221         *childregs = *current_pt_regs();
 222         /* Set the correct stack for the clone mode */
 223         if (usp)
 224                 childregs->ctx.AX[0].U0 = ALIGN(usp, 8);
 225         tsk->thread.int_depth = 1;
 226
 227         /* set return value for child process */
 228         childregs->ctx.DX[0].U0 = 0;
 229
 230         /* The TLS pointer is passed as an argument to sys_clone. */
 231         if (clone_flags & CLONE_SETTLS)
 232                 tsk->thread.tls_ptr =
 233                                 (__force void __user *)childregs->ctx.DX[1].U1;
 234
 235 #ifdef CONFIG_METAG_FPU
 236         if (tsk->thread.fpu_context) {
 237                 struct meta_fpu_context *ctx;
 238
 239                 ctx = kmemdup(tsk->thread.fpu_context,
 240                               sizeof(struct meta_fpu_context), GFP_ATOMIC);
 241                 tsk->thread.fpu_context = ctx;
 242         }
 243 #endif
 244
 245 #ifdef CONFIG_METAG_DSP
 246         if (tsk->thread.dsp_context) {
 247                 struct meta_ext_context *ctx;
 248                 int i;
 249
 250                 ctx = kmemdup(tsk->thread.dsp_context,
 251                               sizeof(struct meta_ext_context), GFP_ATOMIC);
 252                 for (i = 0; i < 2; i++)
 253                         ctx->ram[i] = kmemdup(ctx->ram[i], ctx->ram_sz[i],
 254                                               GFP_ATOMIC);
 255                 tsk->thread.dsp_context = ctx;
 256         }
 257 #endif
 258
 259         return 0;
 260 }
 261
 262 #ifdef CONFIG_METAG_FPU
 263 static void alloc_fpu_context(struct thread_struct *thread)
 264 {
 265         thread->fpu_context = kzalloc(sizeof(struct meta_fpu_context),
 266                                       GFP_ATOMIC);
 267 }
 268
 269 static void clear_fpu(struct thread_struct *thread)
 270 {
 271         thread->user_flags &= ~TBICTX_FPAC_BIT;
 272         kfree(thread->fpu_context);
 273         thread->fpu_context = NULL;
 274 }
 275 #else
 276 static void clear_fpu(struct thread_struct *thread)
 277 {
 278 }
 279 #endif
 280
 281 #ifdef CONFIG_METAG_DSP
 282 static void clear_dsp(struct thread_struct *thread)
 283 {
 284         if (thread->dsp_context) {
 285                 kfree(thread->dsp_context->ram[0]);
 286                 kfree(thread->dsp_context->ram[1]);
 287
 288                 kfree(thread->dsp_context);
 289
 290                 thread->dsp_context = NULL;
 291         }
 292
 293         __core_reg_set(D0.8, 0);
 294 }
 295 #else
 296 static void clear_dsp(struct thread_struct *thread)
 297 {
 298 }
 299 #endif
 300
 301 struct task_struct *__sched __switch_to(struct task_struct *prev,
 302                                         struct task_struct *next)
 303 {
 304         TBIRES to, from;
 305
 306         to.Switch.pCtx = next->thread.kernel_context;
 307         to.Switch.pPara = prev;
 308
 309 #ifdef CONFIG_METAG_FPU
 310         if (prev->thread.user_flags & TBICTX_FPAC_BIT) {
 311                 struct pt_regs *regs = task_pt_regs(prev);
 312                 TBIRES state;
 313
 314                 state.Sig.SaveMask = prev->thread.user_flags;
 315                 state.Sig.pCtx = &regs->ctx;
 316
 317                 if (!prev->thread.fpu_context)
 318                         alloc_fpu_context(&prev->thread);
 319                 if (prev->thread.fpu_context)
 320                         __TBICtxFPUSave(state, prev->thread.fpu_context);
 321         }
 322         /*
 323          * Force a restore of the FPU context next time this process is
 324          * scheduled.
 325          */
 326         if (prev->thread.fpu_context)
 327                 prev->thread.fpu_context->needs_restore = true;
 328 #endif
 329
 330
 331         from = __TBISwitch(to, &prev->thread.kernel_context);
 332
 333         /* Restore TLS pointer for this process. */
 334         set_gateway_tls(current->thread.tls_ptr);
 335
 336         return (struct task_struct *) from.Switch.pPara;
 337 }
 338
 339 void flush_thread(void)
 340 {
 341         clear_fpu(&current->thread);
 342         clear_dsp(&current->thread);
 343 }
 344
 345 /*
 346  * Free current thread data structures etc.
 347  */
 348 void exit_thread(void)
 349 {
 350         clear_fpu(&current->thread);
 351         clear_dsp(&current->thread);
 352 }
 353
 354 /* TODO: figure out how to unwind the kernel stack here to figure out
 355  * where we went to sleep. */
 356 unsigned long get_wchan(struct task_struct *p)
 357 {
 358         return 0;
 359 }
 360
 361 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 362 {
 363         /* Returning 0 indicates that the FPU state was not stored (as it was
 364          * not in use) */
 365         return 0;
 366 }
 367
 368 #ifdef CONFIG_METAG_USER_TCM
 369
 370 #define ELF_MIN_ALIGN   PAGE_SIZE
 371
 372 #define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
 373 #define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
 374 #define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
 375
 376 #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
 377
 378 unsigned long __metag_elf_map(struct file *filep, unsigned long addr,
 379                               struct elf_phdr *eppnt, int prot, int type,
 380                               unsigned long total_size)
 381 {
 382         unsigned long map_addr, size;
 383         unsigned long page_off = ELF_PAGEOFFSET(eppnt->p_vaddr);
 384         unsigned long raw_size = eppnt->p_filesz + page_off;
 385         unsigned long off = eppnt->p_offset - page_off;
 386         unsigned int tcm_tag;
 387         addr = ELF_PAGESTART(addr);
 388         size = ELF_PAGEALIGN(raw_size);
 389
 390         /* mmap() will return -EINVAL if given a zero size, but a
 391          * segment with zero filesize is perfectly valid */
 392         if (!size)
 393                 return addr;
 394
 395         tcm_tag = tcm_lookup_tag(addr);
 396
 397         if (tcm_tag != TCM_INVALID_TAG)
 398                 type &= ~MAP_FIXED;
 399
 400         /*
 401         * total_size is the size of the ELF (interpreter) image.
 402         * The _first_ mmap needs to know the full size, otherwise
 403         * randomization might put this image into an overlapping
 404         * position with the ELF binary image. (since size < total_size)
 405         * So we first map the 'big' image - and unmap the remainder at
 406         * the end. (which unmap is needed for ELF images with holes.)
 407         */
 408         if (total_size) {
 409                 total_size = ELF_PAGEALIGN(total_size);
 410                 map_addr = vm_mmap(filep, addr, total_size, prot, type, off);
 411                 if (!BAD_ADDR(map_addr))
 412                         vm_munmap(map_addr+size, total_size-size);
 413         } else
 414                 map_addr = vm_mmap(filep, addr, size, prot, type, off);
 415
 416         if (!BAD_ADDR(map_addr) && tcm_tag != TCM_INVALID_TAG) {
 417                 struct tcm_allocation *tcm;
 418                 unsigned long tcm_addr;
 419
 420                 tcm = kmalloc(sizeof(*tcm), GFP_KERNEL);
 421                 if (!tcm)
 422                         return -ENOMEM;
 423
 424                 tcm_addr = tcm_alloc(tcm_tag, raw_size);
 425                 if (tcm_addr != addr) {
 426                         kfree(tcm);
 427                         return -ENOMEM;
 428                 }
 429
 430                 tcm->tag = tcm_tag;
 431                 tcm->addr = tcm_addr;
 432                 tcm->size = raw_size;
 433
 434                 list_add(&tcm->list, &current->mm->context.tcm);
 435
 436                 eppnt->p_vaddr = map_addr;
 437                 if (copy_from_user((void *) addr, (void __user *) map_addr,
 438                                    raw_size))
 439                         return -EFAULT;
 440         }
 441
 442         return map_addr;
 443 }
 444 #endif