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/sched/debug.h>
  12 #include <linux/kernel.h>
  13 #include <linux/mm.h>
  14 #include <linux/unistd.h>
  15 #include <linux/ptrace.h>
  16 #include <linux/user.h>
  17 #include <linux/reboot.h>
  18 #include <linux/elfcore.h>
  19 #include <linux/fs.h>
  20 #include <linux/tick.h>
  21 #include <linux/slab.h>
  22 #include <linux/mman.h>
  23 #include <linux/pm.h>
  24 #include <linux/syscalls.h>
  25 #include <linux/uaccess.h>
  26 #include <linux/smp.h>
  27 #include <asm/core_reg.h>
  28 #include <asm/user_gateway.h>
  29 #include <asm/tcm.h>
  30 #include <asm/traps.h>
  31 #include <asm/switch_to.h>
  32
  33 /*
  34  * Wait for the next interrupt and enable local interrupts
  35  */
  36 void arch_cpu_idle(void)
  37 {
  38         int tmp;
  39
  40         /*
  41          * Quickly jump straight into the interrupt entry point without actually
  42          * triggering an interrupt. When TXSTATI gets read the processor will
  43          * block until an interrupt is triggered.
  44          */
  45         asm volatile (/* Switch into ISTAT mode */
  46                       "RTH\n\t"
  47                       /* Enable local interrupts */
  48                       "MOV      TXMASKI, %1\n\t"
  49                       /*
  50                        * We can't directly "SWAP PC, PCX", so we swap via a
  51                        * temporary. Essentially we do:
  52                        *  PCX_new = 1f (the place to continue execution)
  53                        *  PC = PCX_old
  54                        */
  55                       "ADD      %0, CPC0, #(1f-.)\n\t"
  56                       "SWAP     PCX, %0\n\t"
  57                       "MOV      PC, %0\n"
  58                       /* Continue execution here with interrupts enabled */
  59                       "1:"
  60                       : "=a" (tmp)
  61                       : "r" (get_trigger_mask()));
  62 }
  63
  64 #ifdef CONFIG_HOTPLUG_CPU
  65 void arch_cpu_idle_dead(void)
  66 {
  67         cpu_die();
  68 }
  69 #endif
  70
  71 void (*pm_power_off)(void);
  72 EXPORT_SYMBOL(pm_power_off);
  73
  74 void (*soc_restart)(char *cmd);
  75 void (*soc_halt)(void);
  76
  77 void machine_restart(char *cmd)
  78 {
  79         if (soc_restart)
  80                 soc_restart(cmd);
  81         hard_processor_halt(HALT_OK);
  82 }
  83
  84 void machine_halt(void)
  85 {
  86         if (soc_halt)
  87                 soc_halt();
  88         smp_send_stop();
  89         hard_processor_halt(HALT_OK);
  90 }
  91
  92 void machine_power_off(void)
  93 {
  94         if (pm_power_off)
  95                 pm_power_off();
  96         smp_send_stop();
  97         hard_processor_halt(HALT_OK);
  98 }
  99
 100 #define FLAG_Z 0x8
 101 #define FLAG_N 0x4
 102 #define FLAG_O 0x2
 103 #define FLAG_C 0x1
 104
 105 void show_regs(struct pt_regs *regs)
 106 {
 107         int i;
 108         const char *AX0_names[] = {"A0StP", "A0FrP"};
 109         const char *AX1_names[] = {"A1GbP", "A1LbP"};
 110
 111         const char *DX0_names[] = {
 112                 "D0Re0",
 113                 "D0Ar6",
 114                 "D0Ar4",
 115                 "D0Ar2",
 116                 "D0FrT",
 117                 "D0.5 ",
 118                 "D0.6 ",
 119                 "D0.7 "
 120         };
 121
 122         const char *DX1_names[] = {
 123                 "D1Re0",
 124                 "D1Ar5",
 125                 "D1Ar3",
 126                 "D1Ar1",
 127                 "D1RtP",
 128                 "D1.5 ",
 129                 "D1.6 ",
 130                 "D1.7 "
 131         };
 132
 133         show_regs_print_info(KERN_INFO);
 134
 135         pr_info(" pt_regs @ %p\n", regs);
 136         pr_info(" SaveMask = 0x%04hx\n", regs->ctx.SaveMask);
 137         pr_info(" Flags = 0x%04hx (%c%c%c%c)\n", regs->ctx.Flags,
 138                 regs->ctx.Flags & FLAG_Z ? 'Z' : 'z',
 139                 regs->ctx.Flags & FLAG_N ? 'N' : 'n',
 140                 regs->ctx.Flags & FLAG_O ? 'O' : 'o',
 141                 regs->ctx.Flags & FLAG_C ? 'C' : 'c');
 142         pr_info(" TXRPT = 0x%08x\n", regs->ctx.CurrRPT);
 143         pr_info(" PC = 0x%08x\n", regs->ctx.CurrPC);
 144
 145         /* AX regs */
 146         for (i = 0; i < 2; i++) {
 147                 pr_info(" %s = 0x%08x    ",
 148                         AX0_names[i],
 149                         regs->ctx.AX[i].U0);
 150                 printk(" %s = 0x%08x\n",
 151                         AX1_names[i],
 152                         regs->ctx.AX[i].U1);
 153         }
 154
 155         if (regs->ctx.SaveMask & TBICTX_XEXT_BIT)
 156                 pr_warn(" Extended state present - AX2.[01] will be WRONG\n");
 157
 158         /* Special place with AXx.2 */
 159         pr_info(" A0.2  = 0x%08x    ",
 160                 regs->ctx.Ext.AX2.U0);
 161         printk(" A1.2  = 0x%08x\n",
 162                 regs->ctx.Ext.AX2.U1);
 163
 164         /* 'extended' AX regs (nominally, just AXx.3) */
 165         for (i = 0; i < (TBICTX_AX_REGS - 3); i++) {
 166                 pr_info(" A0.%d  = 0x%08x    ", i + 3, regs->ctx.AX3[i].U0);
 167                 printk(" A1.%d  = 0x%08x\n", i + 3, regs->ctx.AX3[i].U1);
 168         }
 169
 170         for (i = 0; i < 8; i++) {
 171                 pr_info(" %s = 0x%08x    ", DX0_names[i], regs->ctx.DX[i].U0);
 172                 printk(" %s = 0x%08x\n", DX1_names[i], regs->ctx.DX[i].U1);
 173         }
 174
 175         show_trace(NULL, (unsigned long *)regs->ctx.AX[0].U0, regs);
 176 }
 177
 178 /*
 179  * Copy architecture-specific thread state
 180  */
 181 int copy_thread(unsigned long clone_flags, unsigned long usp,
 182                 unsigned long kthread_arg, struct task_struct *tsk)
 183 {
 184         struct pt_regs *childregs = task_pt_regs(tsk);
 185         void *kernel_context = ((void *) childregs +
 186                                 sizeof(struct pt_regs));
 187         unsigned long global_base;
 188
 189         BUG_ON(((unsigned long)childregs) & 0x7);
 190         BUG_ON(((unsigned long)kernel_context) & 0x7);
 191
 192         memset(&tsk->thread.kernel_context, 0,
 193                         sizeof(tsk->thread.kernel_context));
 194
 195         tsk->thread.kernel_context = __TBISwitchInit(kernel_context,
 196                                                      ret_from_fork,
 197                                                      0, 0);
 198
 199         if (unlikely(tsk->flags & PF_KTHREAD)) {
 200                 /*
 201                  * Make sure we don't leak any kernel data to child's regs
 202                  * if kernel thread becomes a userspace thread in the future
 203                  */
 204                 memset(childregs, 0 , sizeof(struct pt_regs));
 205
 206                 global_base = __core_reg_get(A1GbP);
 207                 childregs->ctx.AX[0].U1 = (unsigned long) global_base;
 208                 childregs->ctx.AX[0].U0 = (unsigned long) kernel_context;
 209                 /* Set D1Ar1=kthread_arg and D1RtP=usp (fn) */
 210                 childregs->ctx.DX[4].U1 = usp;
 211                 childregs->ctx.DX[3].U1 = kthread_arg;
 212                 tsk->thread.int_depth = 2;
 213                 return 0;
 214         }
 215
 216         /*
 217          * Get a pointer to where the new child's register block should have
 218          * been pushed.
 219          * The Meta's stack grows upwards, and the context is the the first
 220          * thing to be pushed by TBX (phew)
 221          */
 222         *childregs = *current_pt_regs();
 223         /* Set the correct stack for the clone mode */
 224         if (usp)
 225                 childregs->ctx.AX[0].U0 = ALIGN(usp, 8);
 226         tsk->thread.int_depth = 1;
 227
 228         /* set return value for child process */
 229         childregs->ctx.DX[0].U0 = 0;
 230
 231         /* The TLS pointer is passed as an argument to sys_clone. */
 232         if (clone_flags & CLONE_SETTLS)
 233                 tsk->thread.tls_ptr =
 234                                 (__force void __user *)childregs->ctx.DX[1].U1;
 235
 236 #ifdef CONFIG_METAG_FPU
 237         if (tsk->thread.fpu_context) {
 238                 struct meta_fpu_context *ctx;
 239
 240                 ctx = kmemdup(tsk->thread.fpu_context,
 241                               sizeof(struct meta_fpu_context), GFP_ATOMIC);
 242                 tsk->thread.fpu_context = ctx;
 243         }
 244 #endif
 245
 246 #ifdef CONFIG_METAG_DSP
 247         if (tsk->thread.dsp_context) {
 248                 struct meta_ext_context *ctx;
 249                 int i;
 250
 251                 ctx = kmemdup(tsk->thread.dsp_context,
 252                               sizeof(struct meta_ext_context), GFP_ATOMIC);
 253                 for (i = 0; i < 2; i++)
 254                         ctx->ram[i] = kmemdup(ctx->ram[i], ctx->ram_sz[i],
 255                                               GFP_ATOMIC);
 256                 tsk->thread.dsp_context = ctx;
 257         }
 258 #endif
 259
 260         return 0;
 261 }
 262
 263 #ifdef CONFIG_METAG_FPU
 264 static void alloc_fpu_context(struct thread_struct *thread)
 265 {
 266         thread->fpu_context = kzalloc(sizeof(struct meta_fpu_context),
 267                                       GFP_ATOMIC);
 268 }
 269
 270 static void clear_fpu(struct thread_struct *thread)
 271 {
 272         thread->user_flags &= ~TBICTX_FPAC_BIT;
 273         kfree(thread->fpu_context);
 274         thread->fpu_context = NULL;
 275 }
 276 #else
 277 static void clear_fpu(struct thread_struct *thread)
 278 {
 279 }
 280 #endif
 281
 282 #ifdef CONFIG_METAG_DSP
 283 static void clear_dsp(struct thread_struct *thread)
 284 {
 285         if (thread->dsp_context) {
 286                 kfree(thread->dsp_context->ram[0]);
 287                 kfree(thread->dsp_context->ram[1]);
 288
 289                 kfree(thread->dsp_context);
 290
 291                 thread->dsp_context = NULL;
 292         }
 293
 294         __core_reg_set(D0.8, 0);
 295 }
 296 #else
 297 static void clear_dsp(struct thread_struct *thread)
 298 {
 299 }
 300 #endif
 301
 302 struct task_struct *__sched __switch_to(struct task_struct *prev,
 303                                         struct task_struct *next)
 304 {
 305         TBIRES to, from;
 306
 307         to.Switch.pCtx = next->thread.kernel_context;
 308         to.Switch.pPara = prev;
 309
 310 #ifdef CONFIG_METAG_FPU
 311         if (prev->thread.user_flags & TBICTX_FPAC_BIT) {
 312                 struct pt_regs *regs = task_pt_regs(prev);
 313                 TBIRES state;
 314
 315                 state.Sig.SaveMask = prev->thread.user_flags;
 316                 state.Sig.pCtx = &regs->ctx;
 317
 318                 if (!prev->thread.fpu_context)
 319                         alloc_fpu_context(&prev->thread);
 320                 if (prev->thread.fpu_context)
 321                         __TBICtxFPUSave(state, prev->thread.fpu_context);
 322         }
 323         /*
 324          * Force a restore of the FPU context next time this process is
 325          * scheduled.
 326          */
 327         if (prev->thread.fpu_context)
 328                 prev->thread.fpu_context->needs_restore = true;
 329 #endif
 330
 331
 332         from = __TBISwitch(to, &prev->thread.kernel_context);
 333
 334         /* Restore TLS pointer for this process. */
 335         set_gateway_tls(current->thread.tls_ptr);
 336
 337         return (struct task_struct *) from.Switch.pPara;
 338 }
 339
 340 void flush_thread(void)
 341 {
 342         clear_fpu(&current->thread);
 343         clear_dsp(&current->thread);
 344 }
 345
 346 /*
 347  * Free current thread data structures etc.
 348  */
 349 void exit_thread(struct task_struct *tsk)
 350 {
 351         clear_fpu(&tsk->thread);
 352         clear_dsp(&tsk->thread);
 353 }
 354
 355 /* TODO: figure out how to unwind the kernel stack here to figure out
 356  * where we went to sleep. */
 357 unsigned long get_wchan(struct task_struct *p)
 358 {
 359         return 0;
 360 }
 361
 362 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 363 {
 364         /* Returning 0 indicates that the FPU state was not stored (as it was
 365          * not in use) */
 366         return 0;
 367 }
 368
 369 #ifdef CONFIG_METAG_USER_TCM
 370
 371 #define ELF_MIN_ALIGN   PAGE_SIZE
 372
 373 #define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
 374 #define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
 375 #define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
 376
 377 #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
 378
 379 unsigned long __metag_elf_map(struct file *filep, unsigned long addr,
 380                               struct elf_phdr *eppnt, int prot, int type,
 381                               unsigned long total_size)
 382 {
 383         unsigned long map_addr, size;
 384         unsigned long page_off = ELF_PAGEOFFSET(eppnt->p_vaddr);
 385         unsigned long raw_size = eppnt->p_filesz + page_off;
 386         unsigned long off = eppnt->p_offset - page_off;
 387         unsigned int tcm_tag;
 388         addr = ELF_PAGESTART(addr);
 389         size = ELF_PAGEALIGN(raw_size);
 390
 391         /* mmap() will return -EINVAL if given a zero size, but a
 392          * segment with zero filesize is perfectly valid */
 393         if (!size)
 394                 return addr;
 395
 396         tcm_tag = tcm_lookup_tag(addr);
 397
 398         if (tcm_tag != TCM_INVALID_TAG)
 399                 type &= ~MAP_FIXED;
 400
 401         /*
 402         * total_size is the size of the ELF (interpreter) image.
 403         * The _first_ mmap needs to know the full size, otherwise
 404         * randomization might put this image into an overlapping
 405         * position with the ELF binary image. (since size < total_size)
 406         * So we first map the 'big' image - and unmap the remainder at
 407         * the end. (which unmap is needed for ELF images with holes.)
 408         */
 409         if (total_size) {
 410                 total_size = ELF_PAGEALIGN(total_size);
 411                 map_addr = vm_mmap(filep, addr, total_size, prot, type, off);
 412                 if (!BAD_ADDR(map_addr))
 413                         vm_munmap(map_addr+size, total_size-size);
 414         } else
 415                 map_addr = vm_mmap(filep, addr, size, prot, type, off);
 416
 417         if (!BAD_ADDR(map_addr) && tcm_tag != TCM_INVALID_TAG) {
 418                 struct tcm_allocation *tcm;
 419                 unsigned long tcm_addr;
 420
 421                 tcm = kmalloc(sizeof(*tcm), GFP_KERNEL);
 422                 if (!tcm)
 423                         return -ENOMEM;
 424
 425                 tcm_addr = tcm_alloc(tcm_tag, raw_size);
 426                 if (tcm_addr != addr) {
 427                         kfree(tcm);
 428                         return -ENOMEM;
 429                 }
 430
 431                 tcm->tag = tcm_tag;
 432                 tcm->addr = tcm_addr;
 433                 tcm->size = raw_size;
 434
 435                 list_add(&tcm->list, &current->mm->context.tcm);
 436
 437                 eppnt->p_vaddr = map_addr;
 438                 if (copy_from_user((void *) addr, (void __user *) map_addr,
 439                                    raw_size))
 440                         return -EFAULT;
 441         }
 442
 443         return map_addr;
 444 }
 445 #endif