target/nios2/cpu.c

   1 /*
   2  * QEMU Nios II CPU
   3  *
   4  * Copyright (c) 2012 Chris Wulff <crwulff@gmail.com>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see
  18  * <http://www.gnu.org/licenses/lgpl-2.1.html>
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include "qemu/module.h"
  23 #include "qapi/error.h"
  24 #include "cpu.h"
  25 #include "exec/log.h"
  26 #include "exec/gdbstub.h"
  27 #include "hw/qdev-properties.h"
  28
  29 static void nios2_cpu_set_pc(CPUState *cs, vaddr value)
  30 {
  31     Nios2CPU *cpu = NIOS2_CPU(cs);
  32     CPUNios2State *env = &cpu->env;
  33
  34     env->pc = value;
  35 }
  36
  37 static vaddr nios2_cpu_get_pc(CPUState *cs)
  38 {
  39     Nios2CPU *cpu = NIOS2_CPU(cs);
  40     CPUNios2State *env = &cpu->env;
  41
  42     return env->pc;
  43 }
  44
  45 static void nios2_restore_state_to_opc(CPUState *cs,
  46                                        const TranslationBlock *tb,
  47                                        const uint64_t *data)
  48 {
  49     Nios2CPU *cpu = NIOS2_CPU(cs);
  50     CPUNios2State *env = &cpu->env;
  51
  52     env->pc = data[0];
  53 }
  54
  55 static bool nios2_cpu_has_work(CPUState *cs)
  56 {
  57     return cs->interrupt_request & CPU_INTERRUPT_HARD;
  58 }
  59
  60 static void nios2_cpu_reset(DeviceState *dev)
  61 {
  62     CPUState *cs = CPU(dev);
  63     Nios2CPU *cpu = NIOS2_CPU(cs);
  64     Nios2CPUClass *ncc = NIOS2_CPU_GET_CLASS(cpu);
  65     CPUNios2State *env = &cpu->env;
  66
  67     ncc->parent_reset(dev);
  68
  69     memset(env->ctrl, 0, sizeof(env->ctrl));
  70     env->pc = cpu->reset_addr;
  71
  72 #if defined(CONFIG_USER_ONLY)
  73     /* Start in user mode with interrupts enabled. */
  74     env->ctrl[CR_STATUS] = CR_STATUS_RSIE | CR_STATUS_U | CR_STATUS_PIE;
  75     memset(env->regs, 0, sizeof(env->regs));
  76 #else
  77     env->ctrl[CR_STATUS] = CR_STATUS_RSIE;
  78     nios2_update_crs(env);
  79     memset(env->shadow_regs, 0, sizeof(env->shadow_regs));
  80 #endif
  81 }
  82
  83 #ifndef CONFIG_USER_ONLY
  84 static void eic_set_irq(void *opaque, int irq, int level)
  85 {
  86     Nios2CPU *cpu = opaque;
  87     CPUState *cs = CPU(cpu);
  88
  89     if (level) {
  90         cpu_interrupt(cs, CPU_INTERRUPT_HARD);
  91     } else {
  92         cpu_reset_interrupt(cs, CPU_INTERRUPT_HARD);
  93     }
  94 }
  95
  96 static void iic_set_irq(void *opaque, int irq, int level)
  97 {
  98     Nios2CPU *cpu = opaque;
  99     CPUNios2State *env = &cpu->env;
 100     CPUState *cs = CPU(cpu);
 101
 102     env->ctrl[CR_IPENDING] = deposit32(env->ctrl[CR_IPENDING], irq, 1, !!level);
 103
 104     if (env->ctrl[CR_IPENDING]) {
 105         cpu_interrupt(cs, CPU_INTERRUPT_HARD);
 106     } else {
 107         cpu_reset_interrupt(cs, CPU_INTERRUPT_HARD);
 108     }
 109 }
 110 #endif
 111
 112 static void nios2_cpu_initfn(Object *obj)
 113 {
 114     Nios2CPU *cpu = NIOS2_CPU(obj);
 115
 116     cpu_set_cpustate_pointers(cpu);
 117
 118 #if !defined(CONFIG_USER_ONLY)
 119     mmu_init(&cpu->env);
 120 #endif
 121 }
 122
 123 static ObjectClass *nios2_cpu_class_by_name(const char *cpu_model)
 124 {
 125     return object_class_by_name(TYPE_NIOS2_CPU);
 126 }
 127
 128 static void realize_cr_status(CPUState *cs)
 129 {
 130     Nios2CPU *cpu = NIOS2_CPU(cs);
 131
 132     /* Begin with all fields of all registers are reserved. */
 133     memset(cpu->cr_state, 0, sizeof(cpu->cr_state));
 134
 135     /*
 136      * The combination of writable and readonly is the set of all
 137      * non-reserved fields.  We apply writable as a mask to bits,
 138      * and merge in existing readonly bits, before storing.
 139      */
 140 #define WR_REG(C)       cpu->cr_state[C].writable = -1
 141 #define RO_REG(C)       cpu->cr_state[C].readonly = -1
 142 #define WR_FIELD(C, F)  cpu->cr_state[C].writable |= R_##C##_##F##_MASK
 143 #define RO_FIELD(C, F)  cpu->cr_state[C].readonly |= R_##C##_##F##_MASK
 144
 145     WR_FIELD(CR_STATUS, PIE);
 146     WR_REG(CR_ESTATUS);
 147     WR_REG(CR_BSTATUS);
 148     RO_REG(CR_CPUID);
 149     RO_REG(CR_EXCEPTION);
 150     WR_REG(CR_BADADDR);
 151
 152     if (cpu->eic_present) {
 153         WR_FIELD(CR_STATUS, RSIE);
 154         RO_FIELD(CR_STATUS, NMI);
 155         WR_FIELD(CR_STATUS, PRS);
 156         RO_FIELD(CR_STATUS, CRS);
 157         WR_FIELD(CR_STATUS, IL);
 158         WR_FIELD(CR_STATUS, IH);
 159     } else {
 160         RO_FIELD(CR_STATUS, RSIE);
 161         WR_REG(CR_IENABLE);
 162         RO_REG(CR_IPENDING);
 163     }
 164
 165     if (cpu->mmu_present) {
 166         WR_FIELD(CR_STATUS, U);
 167         WR_FIELD(CR_STATUS, EH);
 168
 169         WR_FIELD(CR_PTEADDR, VPN);
 170         WR_FIELD(CR_PTEADDR, PTBASE);
 171
 172         RO_FIELD(CR_TLBMISC, D);
 173         RO_FIELD(CR_TLBMISC, PERM);
 174         RO_FIELD(CR_TLBMISC, BAD);
 175         RO_FIELD(CR_TLBMISC, DBL);
 176         WR_FIELD(CR_TLBMISC, PID);
 177         WR_FIELD(CR_TLBMISC, WE);
 178         WR_FIELD(CR_TLBMISC, RD);
 179         WR_FIELD(CR_TLBMISC, WAY);
 180
 181         WR_REG(CR_TLBACC);
 182     }
 183
 184     /*
 185      * TODO: ECC (config, eccinj) and MPU (config, mpubase, mpuacc) are
 186      * unimplemented, so their corresponding control regs remain reserved.
 187      */
 188
 189 #undef WR_REG
 190 #undef RO_REG
 191 #undef WR_FIELD
 192 #undef RO_FIELD
 193 }
 194
 195 static void nios2_cpu_realizefn(DeviceState *dev, Error **errp)
 196 {
 197     CPUState *cs = CPU(dev);
 198     Nios2CPU *cpu = NIOS2_CPU(cs);
 199     Nios2CPUClass *ncc = NIOS2_CPU_GET_CLASS(dev);
 200     Error *local_err = NULL;
 201
 202 #ifndef CONFIG_USER_ONLY
 203     if (cpu->eic_present) {
 204         qdev_init_gpio_in_named(DEVICE(cpu), eic_set_irq, "EIC", 1);
 205     } else {
 206         qdev_init_gpio_in_named(DEVICE(cpu), iic_set_irq, "IRQ", 32);
 207     }
 208 #endif
 209
 210     cpu_exec_realizefn(cs, &local_err);
 211     if (local_err != NULL) {
 212         error_propagate(errp, local_err);
 213         return;
 214     }
 215
 216     realize_cr_status(cs);
 217     qemu_init_vcpu(cs);
 218     cpu_reset(cs);
 219
 220     /* We have reserved storage for cpuid; might as well use it. */
 221     cpu->env.ctrl[CR_CPUID] = cs->cpu_index;
 222
 223     ncc->parent_realize(dev, errp);
 224 }
 225
 226 #ifndef CONFIG_USER_ONLY
 227 static bool eic_take_interrupt(Nios2CPU *cpu)
 228 {
 229     CPUNios2State *env = &cpu->env;
 230     const uint32_t status = env->ctrl[CR_STATUS];
 231
 232     if (cpu->rnmi) {
 233         return !(status & CR_STATUS_NMI);
 234     }
 235     if (!(status & CR_STATUS_PIE)) {
 236         return false;
 237     }
 238     if (cpu->ril <= FIELD_EX32(status, CR_STATUS, IL)) {
 239         return false;
 240     }
 241     if (cpu->rrs != FIELD_EX32(status, CR_STATUS, CRS)) {
 242         return true;
 243     }
 244     return status & CR_STATUS_RSIE;
 245 }
 246
 247 static bool iic_take_interrupt(Nios2CPU *cpu)
 248 {
 249     CPUNios2State *env = &cpu->env;
 250
 251     if (!(env->ctrl[CR_STATUS] & CR_STATUS_PIE)) {
 252         return false;
 253     }
 254     return env->ctrl[CR_IPENDING] & env->ctrl[CR_IENABLE];
 255 }
 256
 257 static bool nios2_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
 258 {
 259     Nios2CPU *cpu = NIOS2_CPU(cs);
 260
 261     if (interrupt_request & CPU_INTERRUPT_HARD) {
 262         if (cpu->eic_present
 263             ? eic_take_interrupt(cpu)
 264             : iic_take_interrupt(cpu)) {
 265             cs->exception_index = EXCP_IRQ;
 266             nios2_cpu_do_interrupt(cs);
 267             return true;
 268         }
 269     }
 270     return false;
 271 }
 272 #endif /* !CONFIG_USER_ONLY */
 273
 274 static void nios2_cpu_disas_set_info(CPUState *cpu, disassemble_info *info)
 275 {
 276     /* NOTE: NiosII R2 is not supported yet. */
 277     info->mach = bfd_arch_nios2;
 278     info->print_insn = print_insn_nios2;
 279 }
 280
 281 static int nios2_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
 282 {
 283     Nios2CPU *cpu = NIOS2_CPU(cs);
 284     CPUNios2State *env = &cpu->env;
 285     uint32_t val;
 286
 287     if (n < 32) {          /* GP regs */
 288         val = env->regs[n];
 289     } else if (n == 32) {    /* PC */
 290         val = env->pc;
 291     } else if (n < 49) {     /* Status regs */
 292         unsigned cr = n - 33;
 293         if (nios2_cr_reserved(&cpu->cr_state[cr])) {
 294             val = 0;
 295         } else {
 296             val = env->ctrl[n - 33];
 297         }
 298     } else {
 299         /* Invalid regs */
 300         return 0;
 301     }
 302
 303     return gdb_get_reg32(mem_buf, val);
 304 }
 305
 306 static int nios2_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
 307 {
 308     Nios2CPU *cpu = NIOS2_CPU(cs);
 309     CPUClass *cc = CPU_GET_CLASS(cs);
 310     CPUNios2State *env = &cpu->env;
 311     uint32_t val;
 312
 313     if (n > cc->gdb_num_core_regs) {
 314         return 0;
 315     }
 316     val = ldl_p(mem_buf);
 317
 318     if (n < 32) {            /* GP regs */
 319         env->regs[n] = val;
 320     } else if (n == 32) {    /* PC */
 321         env->pc = val;
 322     } else if (n < 49) {     /* Status regs */
 323         unsigned cr = n - 33;
 324         /* ??? Maybe allow the debugger to write to readonly fields. */
 325         val &= cpu->cr_state[cr].writable;
 326         val |= cpu->cr_state[cr].readonly & env->ctrl[cr];
 327         env->ctrl[cr] = val;
 328     } else {
 329         g_assert_not_reached();
 330     }
 331
 332     return 4;
 333 }
 334
 335 static Property nios2_properties[] = {
 336     DEFINE_PROP_BOOL("diverr_present", Nios2CPU, diverr_present, true),
 337     DEFINE_PROP_BOOL("mmu_present", Nios2CPU, mmu_present, true),
 338     /* ALTR,pid-num-bits */
 339     DEFINE_PROP_UINT32("mmu_pid_num_bits", Nios2CPU, pid_num_bits, 8),
 340     /* ALTR,tlb-num-ways */
 341     DEFINE_PROP_UINT32("mmu_tlb_num_ways", Nios2CPU, tlb_num_ways, 16),
 342     /* ALTR,tlb-num-entries */
 343     DEFINE_PROP_UINT32("mmu_pid_num_entries", Nios2CPU, tlb_num_entries, 256),
 344     DEFINE_PROP_END_OF_LIST(),
 345 };
 346
 347 #ifndef CONFIG_USER_ONLY
 348 #include "hw/core/sysemu-cpu-ops.h"
 349
 350 static const struct SysemuCPUOps nios2_sysemu_ops = {
 351     .get_phys_page_debug = nios2_cpu_get_phys_page_debug,
 352 };
 353 #endif
 354
 355 #include "hw/core/tcg-cpu-ops.h"
 356
 357 static const struct TCGCPUOps nios2_tcg_ops = {
 358     .initialize = nios2_tcg_init,
 359     .restore_state_to_opc = nios2_restore_state_to_opc,
 360
 361 #ifndef CONFIG_USER_ONLY
 362     .tlb_fill = nios2_cpu_tlb_fill,
 363     .cpu_exec_interrupt = nios2_cpu_exec_interrupt,
 364     .do_interrupt = nios2_cpu_do_interrupt,
 365     .do_unaligned_access = nios2_cpu_do_unaligned_access,
 366 #endif /* !CONFIG_USER_ONLY */
 367 };
 368
 369 static void nios2_cpu_class_init(ObjectClass *oc, void *data)
 370 {
 371     DeviceClass *dc = DEVICE_CLASS(oc);
 372     CPUClass *cc = CPU_CLASS(oc);
 373     Nios2CPUClass *ncc = NIOS2_CPU_CLASS(oc);
 374
 375     device_class_set_parent_realize(dc, nios2_cpu_realizefn,
 376                                     &ncc->parent_realize);
 377     device_class_set_props(dc, nios2_properties);
 378     device_class_set_parent_reset(dc, nios2_cpu_reset, &ncc->parent_reset);
 379
 380     cc->class_by_name = nios2_cpu_class_by_name;
 381     cc->has_work = nios2_cpu_has_work;
 382     cc->dump_state = nios2_cpu_dump_state;
 383     cc->set_pc = nios2_cpu_set_pc;
 384     cc->get_pc = nios2_cpu_get_pc;
 385     cc->disas_set_info = nios2_cpu_disas_set_info;
 386 #ifndef CONFIG_USER_ONLY
 387     cc->sysemu_ops = &nios2_sysemu_ops;
 388 #endif
 389     cc->gdb_read_register = nios2_cpu_gdb_read_register;
 390     cc->gdb_write_register = nios2_cpu_gdb_write_register;
 391     cc->gdb_num_core_regs = 49;
 392     cc->tcg_ops = &nios2_tcg_ops;
 393 }
 394
 395 static const TypeInfo nios2_cpu_type_info = {
 396     .name = TYPE_NIOS2_CPU,
 397     .parent = TYPE_CPU,
 398     .instance_size = sizeof(Nios2CPU),
 399     .instance_init = nios2_cpu_initfn,
 400     .class_size = sizeof(Nios2CPUClass),
 401     .class_init = nios2_cpu_class_init,
 402 };
 403
 404 static void nios2_cpu_register_types(void)
 405 {
 406     type_register_static(&nios2_cpu_type_info);
 407 }
 408
 409 type_init(nios2_cpu_register_types)