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