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/sched/task.h>
  13 #include <linux/sched/task_stack.h>
  14 #include <linux/kernel.h>
  15 #include <linux/mm.h>
  16 #include <linux/unistd.h>
  17 #include <linux/ptrace.h>
  18 #include <linux/user.h>
  19 #include <linux/reboot.h>
  20 #include <linux/elfcore.h>
  21 #include <linux/fs.h>
  22 #include <linux/tick.h>
  23 #include <linux/slab.h>
  24 #include <linux/mman.h>
  25 #include <linux/pm.h>
  26 #include <linux/syscalls.h>
  27 #include <linux/uaccess.h>
  28 #include <linux/smp.h>
  29 #include <asm/core_reg.h>
  30 #include <asm/user_gateway.h>
  31 #include <asm/tcm.h>
  32 #include <asm/traps.h>
  33 #include <asm/switch_to.h>
  34
  35 /*
  36  * Wait for the next interrupt and enable local interrupts
  37  */
  38 void arch_cpu_idle(void)
  39 {
  40         int tmp;
  41
  42         /*
  43          * Quickly jump straight into the interrupt entry point without actually
  44          * triggering an interrupt. When TXSTATI gets read the processor will
  45          * block until an interrupt is triggered.
  46          */
  47         asm volatile (/* Switch into ISTAT mode */
  48                       "RTH\n\t"
  49                       /* Enable local interrupts */
  50                       "MOV      TXMASKI, %1\n\t"
  51                       /*
  52                        * We can't directly "SWAP PC, PCX", so we swap via a
  53                        * temporary. Essentially we do:
  54                        *  PCX_new = 1f (the place to continue execution)
  55                        *  PC = PCX_old
  56                        */
  57                       "ADD      %0, CPC0, #(1f-.)\n\t"
  58                       "SWAP     PCX, %0\n\t"
  59                       "MOV      PC, %0\n"
  60                       /* Continue execution here with interrupts enabled */
  61                       "1:"
  62                       : "=a" (tmp)
  63                       : "r" (get_trigger_mask()));
  64 }
  65
  66 #ifdef CONFIG_HOTPLUG_CPU
  67 void arch_cpu_idle_dead(void)
  68 {
  69         cpu_die();
  70 }
  71 #endif
  72
  73 void (*pm_power_off)(void);
  74 EXPORT_SYMBOL(pm_power_off);
  75
  76 void (*soc_restart)(char *cmd);
  77 void (*soc_halt)(void);
  78
  79 void machine_restart(char *cmd)
  80 {
  81         if (soc_restart)
  82                 soc_restart(cmd);
  83         hard_processor_halt(HALT_OK);
  84 }
  85
  86 void machine_halt(void)
  87 {
  88         if (soc_halt)
  89                 soc_halt();
  90         smp_send_stop();
  91         hard_processor_halt(HALT_OK);
  92 }
  93
  94 void machine_power_off(void)
  95 {
  96         if (pm_power_off)
  97                 pm_power_off();
  98         smp_send_stop();
  99         hard_processor_halt(HALT_OK);
 100 }
 101
 102 #define FLAG_Z 0x8
 103 #define FLAG_N 0x4
 104 #define FLAG_O 0x2
 105 #define FLAG_C 0x1
 106
 107 void show_regs(struct pt_regs *regs)
 108 {
 109         int i;
 110         const char *AX0_names[] = {"A0StP", "A0FrP"};
 111         const char *AX1_names[] = {"A1GbP", "A1LbP"};
 112
 113         const char *DX0_names[] = {
 114                 "D0Re0",
 115                 "D0Ar6",
 116                 "D0Ar4",
 117                 "D0Ar2",
 118                 "D0FrT",
 119                 "D0.5 ",
 120                 "D0.6 ",
 121                 "D0.7 "
 122         };
 123
 124         const char *DX1_names[] = {
 125                 "D1Re0",
 126                 "D1Ar5",
 127                 "D1Ar3",
 128                 "D1Ar1",
 129                 "D1RtP",
 130                 "D1.5 ",
 131                 "D1.6 ",
 132                 "D1.7 "
 133         };
 134
 135         show_regs_print_info(KERN_INFO);
 136
 137         pr_info(" pt_regs @ %p\n", regs);
 138         pr_info(" SaveMask = 0x%04hx\n", regs->ctx.SaveMask);
 139         pr_info(" Flags = 0x%04hx (%c%c%c%c)\n", regs->ctx.Flags,
 140                 regs->ctx.Flags & FLAG_Z ? 'Z' : 'z',
 141                 regs->ctx.Flags & FLAG_N ? 'N' : 'n',
 142                 regs->ctx.Flags & FLAG_O ? 'O' : 'o',
 143                 regs->ctx.Flags & FLAG_C ? 'C' : 'c');
 144         pr_info(" TXRPT = 0x%08x\n", regs->ctx.CurrRPT);
 145         pr_info(" PC = 0x%08x\n", regs->ctx.CurrPC);
 146
 147         /* AX regs */
 148         for (i = 0; i < 2; i++) {
 149                 pr_info(" %s = 0x%08x    ",
 150                         AX0_names[i],
 151                         regs->ctx.AX[i].U0);
 152                 printk(" %s = 0x%08x\n",
 153                         AX1_names[i],
 154                         regs->ctx.AX[i].U1);
 155         }
 156
 157         if (regs->ctx.SaveMask & TBICTX_XEXT_BIT)
 158                 pr_warn(" Extended state present - AX2.[01] will be WRONG\n");
 159
 160         /* Special place with AXx.2 */
 161         pr_info(" A0.2  = 0x%08x    ",
 162                 regs->ctx.Ext.AX2.U0);
 163         printk(" A1.2  = 0x%08x\n",
 164                 regs->ctx.Ext.AX2.U1);
 165
 166         /* 'extended' AX regs (nominally, just AXx.3) */
 167         for (i = 0; i < (TBICTX_AX_REGS - 3); i++) {
 168                 pr_info(" A0.%d  = 0x%08x    ", i + 3, regs->ctx.AX3[i].U0);
 169                 printk(" A1.%d  = 0x%08x\n", i + 3, regs->ctx.AX3[i].U1);
 170         }
 171
 172         for (i = 0; i < 8; i++) {
 173                 pr_info(" %s = 0x%08x    ", DX0_names[i], regs->ctx.DX[i].U0);
 174                 printk(" %s = 0x%08x\n", DX1_names[i], regs->ctx.DX[i].U1);
 175         }
 176
 177         show_trace(NULL, (unsigned long *)regs->ctx.AX[0].U0, regs);
 178 }
 179
 180 /*
 181  * Copy architecture-specific thread state
 182  */
 183 int copy_thread(unsigned long clone_flags, unsigned long usp,
 184                 unsigned long kthread_arg, struct task_struct *tsk)
 185 {
 186         struct pt_regs *childregs = task_pt_regs(tsk);
 187         void *kernel_context = ((void *) childregs +
 188                                 sizeof(struct pt_regs));
 189         unsigned long global_base;
 190
 191         BUG_ON(((unsigned long)childregs) & 0x7);
 192         BUG_ON(((unsigned long)kernel_context) & 0x7);
 193
 194         memset(&tsk->thread.kernel_context, 0,
 195                         sizeof(tsk->thread.kernel_context));
 196
 197         tsk->thread.kernel_context = __TBISwitchInit(kernel_context,
 198                                                      ret_from_fork,
 199                                                      0, 0);
 200
 201         if (unlikely(tsk->flags & PF_KTHREAD)) {
 202                 /*
 203                  * Make sure we don't leak any kernel data to child's regs
 204                  * if kernel thread becomes a userspace thread in the future
 205                  */
 206                 memset(childregs, 0 , sizeof(struct pt_regs));
 207
 208                 global_base = __core_reg_get(A1GbP);
 209                 childregs->ctx.AX[0].U1 = (unsigned long) global_base;
 210                 childregs->ctx.AX[0].U0 = (unsigned long) kernel_context;
 211                 /* Set D1Ar1=kthread_arg and D1RtP=usp (fn) */
 212                 childregs->ctx.DX[4].U1 = usp;
 213                 childregs->ctx.DX[3].U1 = kthread_arg;
 214                 tsk->thread.int_depth = 2;
 215                 return 0;
 216         }
 217
 218         /*
 219          * Get a pointer to where the new child's register block should have
 220          * been pushed.
 221          * The Meta's stack grows upwards, and the context is the the first
 222          * thing to be pushed by TBX (phew)
 223          */
 224         *childregs = *current_pt_regs();
 225         /* Set the correct stack for the clone mode */
 226         if (usp)
 227                 childregs->ctx.AX[0].U0 = ALIGN(usp, 8);
 228         tsk->thread.int_depth = 1;
 229
 230         /* set return value for child process */
 231         childregs->ctx.DX[0].U0 = 0;
 232
 233         /* The TLS pointer is passed as an argument to sys_clone. */
 234         if (clone_flags & CLONE_SETTLS)
 235                 tsk->thread.tls_ptr =
 236                                 (__force void __user *)childregs->ctx.DX[1].U1;
 237
 238 #ifdef CONFIG_METAG_FPU
 239         if (tsk->thread.fpu_context) {
 240                 struct meta_fpu_context *ctx;
 241
 242                 ctx = kmemdup(tsk->thread.fpu_context,
 243                               sizeof(struct meta_fpu_context), GFP_ATOMIC);
 244                 tsk->thread.fpu_context = ctx;
 245         }
 246 #endif
 247
 248 #ifdef CONFIG_METAG_DSP
 249         if (tsk->thread.dsp_context) {
 250                 struct meta_ext_context *ctx;
 251                 int i;
 252
 253                 ctx = kmemdup(tsk->thread.dsp_context,
 254                               sizeof(struct meta_ext_context), GFP_ATOMIC);
 255                 for (i = 0; i < 2; i++)
 256                         ctx->ram[i] = kmemdup(ctx->ram[i], ctx->ram_sz[i],
 257                                               GFP_ATOMIC);
 258                 tsk->thread.dsp_context = ctx;
 259         }
 260 #endif
 261
 262         return 0;
 263 }
 264
 265 #ifdef CONFIG_METAG_FPU
 266 static void alloc_fpu_context(struct thread_struct *thread)
 267 {
 268         thread->fpu_context = kzalloc(sizeof(struct meta_fpu_context),
 269                                       GFP_ATOMIC);
 270 }
 271
 272 static void clear_fpu(struct thread_struct *thread)
 273 {
 274         thread->user_flags &= ~TBICTX_FPAC_BIT;
 275         kfree(thread->fpu_context);
 276         thread->fpu_context = NULL;
 277 }
 278 #else
 279 static void clear_fpu(struct thread_struct *thread)
 280 {
 281 }
 282 #endif
 283
 284 #ifdef CONFIG_METAG_DSP
 285 static void clear_dsp(struct thread_struct *thread)
 286 {
 287         if (thread->dsp_context) {
 288                 kfree(thread->dsp_context->ram[0]);
 289                 kfree(thread->dsp_context->ram[1]);
 290
 291                 kfree(thread->dsp_context);
 292
 293                 thread->dsp_context = NULL;
 294         }
 295
 296         __core_reg_set(D0.8, 0);
 297 }
 298 #else
 299 static void clear_dsp(struct thread_struct *thread)
 300 {
 301 }
 302 #endif
 303
 304 struct task_struct *__sched __switch_to(struct task_struct *prev,
 305                                         struct task_struct *next)
 306 {
 307         TBIRES to, from;
 308
 309         to.Switch.pCtx = next->thread.kernel_context;
 310         to.Switch.pPara = prev;
 311
 312 #ifdef CONFIG_METAG_FPU
 313         if (prev->thread.user_flags & TBICTX_FPAC_BIT) {
 314                 struct pt_regs *regs = task_pt_regs(prev);
 315                 TBIRES state;
 316
 317                 state.Sig.SaveMask = prev->thread.user_flags;
 318                 state.Sig.pCtx = &regs->ctx;
 319
 320                 if (!prev->thread.fpu_context)
 321                         alloc_fpu_context(&prev->thread);
 322                 if (prev->thread.fpu_context)
 323                         __TBICtxFPUSave(state, prev->thread.fpu_context);
 324         }
 325         /*
 326          * Force a restore of the FPU context next time this process is
 327          * scheduled.
 328          */
 329         if (prev->thread.fpu_context)
 330                 prev->thread.fpu_context->needs_restore = true;
 331 #endif
 332
 333
 334         from = __TBISwitch(to, &prev->thread.kernel_context);
 335
 336         /* Restore TLS pointer for this process. */
 337         set_gateway_tls(current->thread.tls_ptr);
 338
 339         return (struct task_struct *) from.Switch.pPara;
 340 }
 341
 342 void flush_thread(void)
 343 {
 344         clear_fpu(&current->thread);
 345         clear_dsp(&current->thread);
 346 }
 347
 348 /*
 349  * Free current thread data structures etc.
 350  */
 351 void exit_thread(struct task_struct *tsk)
 352 {
 353         clear_fpu(&tsk->thread);
 354         clear_dsp(&tsk->thread);
 355 }
 356
 357 /* TODO: figure out how to unwind the kernel stack here to figure out
 358  * where we went to sleep. */
 359 unsigned long get_wchan(struct task_struct *p)
 360 {
 361         return 0;
 362 }
 363
 364 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 365 {
 366         /* Returning 0 indicates that the FPU state was not stored (as it was
 367          * not in use) */
 368         return 0;
 369 }
 370
 371 #ifdef CONFIG_METAG_USER_TCM
 372
 373 #define ELF_MIN_ALIGN   PAGE_SIZE
 374
 375 #define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
 376 #define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
 377 #define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
 378
 379 #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
 380
 381 unsigned long __metag_elf_map(struct file *filep, unsigned long addr,
 382                               struct elf_phdr *eppnt, int prot, int type,
 383                               unsigned long total_size)
 384 {
 385         unsigned long map_addr, size;
 386         unsigned long page_off = ELF_PAGEOFFSET(eppnt->p_vaddr);
 387         unsigned long raw_size = eppnt->p_filesz + page_off;
 388         unsigned long off = eppnt->p_offset - page_off;
 389         unsigned int tcm_tag;
 390         addr = ELF_PAGESTART(addr);
 391         size = ELF_PAGEALIGN(raw_size);
 392
 393         /* mmap() will return -EINVAL if given a zero size, but a
 394          * segment with zero filesize is perfectly valid */
 395         if (!size)
 396                 return addr;
 397
 398         tcm_tag = tcm_lookup_tag(addr);
 399
 400         if (tcm_tag != TCM_INVALID_TAG)
 401                 type &= ~MAP_FIXED;
 402
 403         /*
 404         * total_size is the size of the ELF (interpreter) image.
 405         * The _first_ mmap needs to know the full size, otherwise
 406         * randomization might put this image into an overlapping
 407         * position with the ELF binary image. (since size < total_size)
 408         * So we first map the 'big' image - and unmap the remainder at
 409         * the end. (which unmap is needed for ELF images with holes.)
 410         */
 411         if (total_size) {
 412                 total_size = ELF_PAGEALIGN(total_size);
 413                 map_addr = vm_mmap(filep, addr, total_size, prot, type, off);
 414                 if (!BAD_ADDR(map_addr))
 415                         vm_munmap(map_addr+size, total_size-size);
 416         } else
 417                 map_addr = vm_mmap(filep, addr, size, prot, type, off);
 418
 419         if (!BAD_ADDR(map_addr) && tcm_tag != TCM_INVALID_TAG) {
 420                 struct tcm_allocation *tcm;
 421                 unsigned long tcm_addr;
 422
 423                 tcm = kmalloc(sizeof(*tcm), GFP_KERNEL);
 424                 if (!tcm)
 425                         return -ENOMEM;
 426
 427                 tcm_addr = tcm_alloc(tcm_tag, raw_size);
 428                 if (tcm_addr != addr) {
 429                         kfree(tcm);
 430                         return -ENOMEM;
 431                 }
 432
 433                 tcm->tag = tcm_tag;
 434                 tcm->addr = tcm_addr;
 435                 tcm->size = raw_size;
 436
 437                 list_add(&tcm->list, &current->mm->context.tcm);
 438
 439                 eppnt->p_vaddr = map_addr;
 440                 if (copy_from_user((void *) addr, (void __user *) map_addr,
 441                                    raw_size))
 442                         return -EFAULT;
 443         }
 444
 445         return map_addr;
 446 }
 447 #endif