arch/metag/kernel/process.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2005,2006,2007,2008,2009,2010,2011 Imagination Technologies
   4  *
   5  * This file contains the architecture-dependent parts of process handling.
   6  *
   7  */
   8
   9 #include <linux/errno.h>
  10 #include <linux/export.h>
  11 #include <linux/sched.h>
  12 #include <linux/sched/debug.h>
  13 #include <linux/sched/task.h>
  14 #include <linux/sched/task_stack.h>
  15 #include <linux/kernel.h>
  16 #include <linux/mm.h>
  17 #include <linux/unistd.h>
  18 #include <linux/ptrace.h>
  19 #include <linux/user.h>
  20 #include <linux/reboot.h>
  21 #include <linux/elfcore.h>
  22 #include <linux/fs.h>
  23 #include <linux/tick.h>
  24 #include <linux/slab.h>
  25 #include <linux/mman.h>
  26 #include <linux/pm.h>
  27 #include <linux/syscalls.h>
  28 #include <linux/uaccess.h>
  29 #include <linux/smp.h>
  30 #include <asm/core_reg.h>
  31 #include <asm/user_gateway.h>
  32 #include <asm/tcm.h>
  33 #include <asm/traps.h>
  34 #include <asm/switch_to.h>
  35
  36 /*
  37  * Wait for the next interrupt and enable local interrupts
  38  */
  39 void arch_cpu_idle(void)
  40 {
  41         int tmp;
  42
  43         /*
  44          * Quickly jump straight into the interrupt entry point without actually
  45          * triggering an interrupt. When TXSTATI gets read the processor will
  46          * block until an interrupt is triggered.
  47          */
  48         asm volatile (/* Switch into ISTAT mode */
  49                       "RTH\n\t"
  50                       /* Enable local interrupts */
  51                       "MOV      TXMASKI, %1\n\t"
  52                       /*
  53                        * We can't directly "SWAP PC, PCX", so we swap via a
  54                        * temporary. Essentially we do:
  55                        *  PCX_new = 1f (the place to continue execution)
  56                        *  PC = PCX_old
  57                        */
  58                       "ADD      %0, CPC0, #(1f-.)\n\t"
  59                       "SWAP     PCX, %0\n\t"
  60                       "MOV      PC, %0\n"
  61                       /* Continue execution here with interrupts enabled */
  62                       "1:"
  63                       : "=a" (tmp)
  64                       : "r" (get_trigger_mask()));
  65 }
  66
  67 #ifdef CONFIG_HOTPLUG_CPU
  68 void arch_cpu_idle_dead(void)
  69 {
  70         cpu_die();
  71 }
  72 #endif
  73
  74 void (*pm_power_off)(void);
  75 EXPORT_SYMBOL(pm_power_off);
  76
  77 void (*soc_restart)(char *cmd);
  78 void (*soc_halt)(void);
  79
  80 void machine_restart(char *cmd)
  81 {
  82         if (soc_restart)
  83                 soc_restart(cmd);
  84         hard_processor_halt(HALT_OK);
  85 }
  86
  87 void machine_halt(void)
  88 {
  89         if (soc_halt)
  90                 soc_halt();
  91         smp_send_stop();
  92         hard_processor_halt(HALT_OK);
  93 }
  94
  95 void machine_power_off(void)
  96 {
  97         if (pm_power_off)
  98                 pm_power_off();
  99         smp_send_stop();
 100         hard_processor_halt(HALT_OK);
 101 }
 102
 103 #define FLAG_Z 0x8
 104 #define FLAG_N 0x4
 105 #define FLAG_O 0x2
 106 #define FLAG_C 0x1
 107
 108 void show_regs(struct pt_regs *regs)
 109 {
 110         int i;
 111         const char *AX0_names[] = {"A0StP", "A0FrP"};
 112         const char *AX1_names[] = {"A1GbP", "A1LbP"};
 113
 114         const char *DX0_names[] = {
 115                 "D0Re0",
 116                 "D0Ar6",
 117                 "D0Ar4",
 118                 "D0Ar2",
 119                 "D0FrT",
 120                 "D0.5 ",
 121                 "D0.6 ",
 122                 "D0.7 "
 123         };
 124
 125         const char *DX1_names[] = {
 126                 "D1Re0",
 127                 "D1Ar5",
 128                 "D1Ar3",
 129                 "D1Ar1",
 130                 "D1RtP",
 131                 "D1.5 ",
 132                 "D1.6 ",
 133                 "D1.7 "
 134         };
 135
 136         show_regs_print_info(KERN_INFO);
 137
 138         pr_info(" pt_regs @ %p\n", regs);
 139         pr_info(" SaveMask = 0x%04hx\n", regs->ctx.SaveMask);
 140         pr_info(" Flags = 0x%04hx (%c%c%c%c)\n", regs->ctx.Flags,
 141                 regs->ctx.Flags & FLAG_Z ? 'Z' : 'z',
 142                 regs->ctx.Flags & FLAG_N ? 'N' : 'n',
 143                 regs->ctx.Flags & FLAG_O ? 'O' : 'o',
 144                 regs->ctx.Flags & FLAG_C ? 'C' : 'c');
 145         pr_info(" TXRPT = 0x%08x\n", regs->ctx.CurrRPT);
 146         pr_info(" PC = 0x%08x\n", regs->ctx.CurrPC);
 147
 148         /* AX regs */
 149         for (i = 0; i < 2; i++) {
 150                 pr_info(" %s = 0x%08x    ",
 151                         AX0_names[i],
 152                         regs->ctx.AX[i].U0);
 153                 printk(" %s = 0x%08x\n",
 154                         AX1_names[i],
 155                         regs->ctx.AX[i].U1);
 156         }
 157
 158         if (regs->ctx.SaveMask & TBICTX_XEXT_BIT)
 159                 pr_warn(" Extended state present - AX2.[01] will be WRONG\n");
 160
 161         /* Special place with AXx.2 */
 162         pr_info(" A0.2  = 0x%08x    ",
 163                 regs->ctx.Ext.AX2.U0);
 164         printk(" A1.2  = 0x%08x\n",
 165                 regs->ctx.Ext.AX2.U1);
 166
 167         /* 'extended' AX regs (nominally, just AXx.3) */
 168         for (i = 0; i < (TBICTX_AX_REGS - 3); i++) {
 169                 pr_info(" A0.%d  = 0x%08x    ", i + 3, regs->ctx.AX3[i].U0);
 170                 printk(" A1.%d  = 0x%08x\n", i + 3, regs->ctx.AX3[i].U1);
 171         }
 172
 173         for (i = 0; i < 8; i++) {
 174                 pr_info(" %s = 0x%08x    ", DX0_names[i], regs->ctx.DX[i].U0);
 175                 printk(" %s = 0x%08x\n", DX1_names[i], regs->ctx.DX[i].U1);
 176         }
 177
 178         show_trace(NULL, (unsigned long *)regs->ctx.AX[0].U0, regs);
 179 }
 180
 181 /*
 182  * Copy architecture-specific thread state
 183  */
 184 int copy_thread(unsigned long clone_flags, unsigned long usp,
 185                 unsigned long kthread_arg, struct task_struct *tsk)
 186 {
 187         struct pt_regs *childregs = task_pt_regs(tsk);
 188         void *kernel_context = ((void *) childregs +
 189                                 sizeof(struct pt_regs));
 190         unsigned long global_base;
 191
 192         BUG_ON(((unsigned long)childregs) & 0x7);
 193         BUG_ON(((unsigned long)kernel_context) & 0x7);
 194
 195         memset(&tsk->thread.kernel_context, 0,
 196                         sizeof(tsk->thread.kernel_context));
 197
 198         tsk->thread.kernel_context = __TBISwitchInit(kernel_context,
 199                                                      ret_from_fork,
 200                                                      0, 0);
 201
 202         if (unlikely(tsk->flags & PF_KTHREAD)) {
 203                 /*
 204                  * Make sure we don't leak any kernel data to child's regs
 205                  * if kernel thread becomes a userspace thread in the future
 206                  */
 207                 memset(childregs, 0 , sizeof(struct pt_regs));
 208
 209                 global_base = __core_reg_get(A1GbP);
 210                 childregs->ctx.AX[0].U1 = (unsigned long) global_base;
 211                 childregs->ctx.AX[0].U0 = (unsigned long) kernel_context;
 212                 /* Set D1Ar1=kthread_arg and D1RtP=usp (fn) */
 213                 childregs->ctx.DX[4].U1 = usp;
 214                 childregs->ctx.DX[3].U1 = kthread_arg;
 215                 tsk->thread.int_depth = 2;
 216                 return 0;
 217         }
 218
 219         /*
 220          * Get a pointer to where the new child's register block should have
 221          * been pushed.
 222          * The Meta's stack grows upwards, and the context is the the first
 223          * thing to be pushed by TBX (phew)
 224          */
 225         *childregs = *current_pt_regs();
 226         /* Set the correct stack for the clone mode */
 227         if (usp)
 228                 childregs->ctx.AX[0].U0 = ALIGN(usp, 8);
 229         tsk->thread.int_depth = 1;
 230
 231         /* set return value for child process */
 232         childregs->ctx.DX[0].U0 = 0;
 233
 234         /* The TLS pointer is passed as an argument to sys_clone. */
 235         if (clone_flags & CLONE_SETTLS)
 236                 tsk->thread.tls_ptr =
 237                                 (__force void __user *)childregs->ctx.DX[1].U1;
 238
 239 #ifdef CONFIG_METAG_FPU
 240         if (tsk->thread.fpu_context) {
 241                 struct meta_fpu_context *ctx;
 242
 243                 ctx = kmemdup(tsk->thread.fpu_context,
 244                               sizeof(struct meta_fpu_context), GFP_ATOMIC);
 245                 tsk->thread.fpu_context = ctx;
 246         }
 247 #endif
 248
 249 #ifdef CONFIG_METAG_DSP
 250         if (tsk->thread.dsp_context) {
 251                 struct meta_ext_context *ctx;
 252                 int i;
 253
 254                 ctx = kmemdup(tsk->thread.dsp_context,
 255                               sizeof(struct meta_ext_context), GFP_ATOMIC);
 256                 for (i = 0; i < 2; i++)
 257                         ctx->ram[i] = kmemdup(ctx->ram[i], ctx->ram_sz[i],
 258                                               GFP_ATOMIC);
 259                 tsk->thread.dsp_context = ctx;
 260         }
 261 #endif
 262
 263         return 0;
 264 }
 265
 266 #ifdef CONFIG_METAG_FPU
 267 static void alloc_fpu_context(struct thread_struct *thread)
 268 {
 269         thread->fpu_context = kzalloc(sizeof(struct meta_fpu_context),
 270                                       GFP_ATOMIC);
 271 }
 272
 273 static void clear_fpu(struct thread_struct *thread)
 274 {
 275         thread->user_flags &= ~TBICTX_FPAC_BIT;
 276         kfree(thread->fpu_context);
 277         thread->fpu_context = NULL;
 278 }
 279 #else
 280 static void clear_fpu(struct thread_struct *thread)
 281 {
 282 }
 283 #endif
 284
 285 #ifdef CONFIG_METAG_DSP
 286 static void clear_dsp(struct thread_struct *thread)
 287 {
 288         if (thread->dsp_context) {
 289                 kfree(thread->dsp_context->ram[0]);
 290                 kfree(thread->dsp_context->ram[1]);
 291
 292                 kfree(thread->dsp_context);
 293
 294                 thread->dsp_context = NULL;
 295         }
 296
 297         __core_reg_set(D0.8, 0);
 298 }
 299 #else
 300 static void clear_dsp(struct thread_struct *thread)
 301 {
 302 }
 303 #endif
 304
 305 struct task_struct *__sched __switch_to(struct task_struct *prev,
 306                                         struct task_struct *next)
 307 {
 308         TBIRES to, from;
 309
 310         to.Switch.pCtx = next->thread.kernel_context;
 311         to.Switch.pPara = prev;
 312
 313 #ifdef CONFIG_METAG_FPU
 314         if (prev->thread.user_flags & TBICTX_FPAC_BIT) {
 315                 struct pt_regs *regs = task_pt_regs(prev);
 316                 TBIRES state;
 317
 318                 state.Sig.SaveMask = prev->thread.user_flags;
 319                 state.Sig.pCtx = &regs->ctx;
 320
 321                 if (!prev->thread.fpu_context)
 322                         alloc_fpu_context(&prev->thread);
 323                 if (prev->thread.fpu_context)
 324                         __TBICtxFPUSave(state, prev->thread.fpu_context);
 325         }
 326         /*
 327          * Force a restore of the FPU context next time this process is
 328          * scheduled.
 329          */
 330         if (prev->thread.fpu_context)
 331                 prev->thread.fpu_context->needs_restore = true;
 332 #endif
 333
 334
 335         from = __TBISwitch(to, &prev->thread.kernel_context);
 336
 337         /* Restore TLS pointer for this process. */
 338         set_gateway_tls(current->thread.tls_ptr);
 339
 340         return (struct task_struct *) from.Switch.pPara;
 341 }
 342
 343 void flush_thread(void)
 344 {
 345         clear_fpu(&current->thread);
 346         clear_dsp(&current->thread);
 347 }
 348
 349 /*
 350  * Free current thread data structures etc.
 351  */
 352 void exit_thread(struct task_struct *tsk)
 353 {
 354         clear_fpu(&tsk->thread);
 355         clear_dsp(&tsk->thread);
 356 }
 357
 358 /* TODO: figure out how to unwind the kernel stack here to figure out
 359  * where we went to sleep. */
 360 unsigned long get_wchan(struct task_struct *p)
 361 {
 362         return 0;
 363 }
 364
 365 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 366 {
 367         /* Returning 0 indicates that the FPU state was not stored (as it was
 368          * not in use) */
 369         return 0;
 370 }
 371
 372 #ifdef CONFIG_METAG_USER_TCM
 373
 374 #define ELF_MIN_ALIGN   PAGE_SIZE
 375
 376 #define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
 377 #define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
 378 #define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
 379
 380 #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
 381
 382 unsigned long __metag_elf_map(struct file *filep, unsigned long addr,
 383                               struct elf_phdr *eppnt, int prot, int type,
 384                               unsigned long total_size)
 385 {
 386         unsigned long map_addr, size;
 387         unsigned long page_off = ELF_PAGEOFFSET(eppnt->p_vaddr);
 388         unsigned long raw_size = eppnt->p_filesz + page_off;
 389         unsigned long off = eppnt->p_offset - page_off;
 390         unsigned int tcm_tag;
 391         addr = ELF_PAGESTART(addr);
 392         size = ELF_PAGEALIGN(raw_size);
 393
 394         /* mmap() will return -EINVAL if given a zero size, but a
 395          * segment with zero filesize is perfectly valid */
 396         if (!size)
 397                 return addr;
 398
 399         tcm_tag = tcm_lookup_tag(addr);
 400
 401         if (tcm_tag != TCM_INVALID_TAG)
 402                 type &= ~MAP_FIXED;
 403
 404         /*
 405         * total_size is the size of the ELF (interpreter) image.
 406         * The _first_ mmap needs to know the full size, otherwise
 407         * randomization might put this image into an overlapping
 408         * position with the ELF binary image. (since size < total_size)
 409         * So we first map the 'big' image - and unmap the remainder at
 410         * the end. (which unmap is needed for ELF images with holes.)
 411         */
 412         if (total_size) {
 413                 total_size = ELF_PAGEALIGN(total_size);
 414                 map_addr = vm_mmap(filep, addr, total_size, prot, type, off);
 415                 if (!BAD_ADDR(map_addr))
 416                         vm_munmap(map_addr+size, total_size-size);
 417         } else
 418                 map_addr = vm_mmap(filep, addr, size, prot, type, off);
 419
 420         if (!BAD_ADDR(map_addr) && tcm_tag != TCM_INVALID_TAG) {
 421                 struct tcm_allocation *tcm;
 422                 unsigned long tcm_addr;
 423
 424                 tcm = kmalloc(sizeof(*tcm), GFP_KERNEL);
 425                 if (!tcm)
 426                         return -ENOMEM;
 427
 428                 tcm_addr = tcm_alloc(tcm_tag, raw_size);
 429                 if (tcm_addr != addr) {
 430                         kfree(tcm);
 431                         return -ENOMEM;
 432                 }
 433
 434                 tcm->tag = tcm_tag;
 435                 tcm->addr = tcm_addr;
 436                 tcm->size = raw_size;
 437
 438                 list_add(&tcm->list, &current->mm->context.tcm);
 439
 440                 eppnt->p_vaddr = map_addr;
 441                 if (copy_from_user((void *) addr, (void __user *) map_addr,
 442                                    raw_size))
 443                         return -EFAULT;
 444         }
 445
 446         return map_addr;
 447 }
 448 #endif