ARM system emulation (Paul Brook)


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@1661 c046a42c-6fe2-441c-8c8c-71466251a162
diff --git a/target-arm/helper.c b/target-arm/helper.c
new file mode 100644
index 0000000..9cf159c
--- /dev/null
+++ b/target-arm/helper.c
@@ -0,0 +1,555 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "cpu.h"
+#include "exec-all.h"
+
+#if defined(CONFIG_USER_ONLY) 
+
+void do_interrupt (CPUState *env)
+{
+    env->exception_index = -1;
+}
+
+int cpu_arm_handle_mmu_fault (CPUState *env, target_ulong address, int rw,
+                              int is_user, int is_softmmu)
+{
+    if (rw == 2) {
+        env->exception_index = EXCP_PREFETCH_ABORT;
+        env->cp15.c6_insn = address;
+    } else {
+        env->exception_index = EXCP_DATA_ABORT;
+        env->cp15.c6_data = address;
+    }
+    return 1;
+}
+
+target_ulong cpu_get_phys_page_debug(CPUState *env, target_ulong addr)
+{
+    return addr;
+}
+
+/* These should probably raise undefined insn exceptions.  */
+void helper_set_cp15(CPUState *env, uint32_t insn, uint32_t val)
+{
+    cpu_abort(env, "cp15 insn %08x\n", insn);
+}
+
+uint32_t helper_get_cp15(CPUState *env, uint32_t insn)
+{
+    cpu_abort(env, "cp15 insn %08x\n", insn);
+    return 0;
+}
+
+void switch_mode(CPUState *env, int mode)
+{
+    if (mode != ARM_CPU_MODE_USR)
+        cpu_abort(env, "Tried to switch out of user mode\n");
+}
+
+#else
+
+/* Map CPU modes onto saved register banks.  */
+static inline int bank_number (int mode)
+{
+    switch (mode) {
+    case ARM_CPU_MODE_USR:
+    case ARM_CPU_MODE_SYS:
+        return 0;
+    case ARM_CPU_MODE_SVC:
+        return 1;
+    case ARM_CPU_MODE_ABT:
+        return 2;
+    case ARM_CPU_MODE_UND:
+        return 3;
+    case ARM_CPU_MODE_IRQ:
+        return 4;
+    case ARM_CPU_MODE_FIQ:
+        return 5;
+    }
+    cpu_abort(cpu_single_env, "Bad mode %x\n", mode);
+    return -1;
+}
+
+void switch_mode(CPUState *env, int mode)
+{
+    int old_mode;
+    int i;
+
+    old_mode = env->uncached_cpsr & CPSR_M;
+    if (mode == old_mode)
+        return;
+
+    if (old_mode == ARM_CPU_MODE_FIQ) {
+        memcpy (env->fiq_regs, env->regs + 8, 5 * sizeof(uint32_t));
+        memcpy (env->regs, env->usr_regs + 8, 5 * sizeof(uint32_t));
+    } else if (mode == ARM_CPU_MODE_FIQ) {
+        memcpy (env->usr_regs, env->regs + 8, 5 * sizeof(uint32_t));
+        memcpy (env->regs, env->fiq_regs + 8, 5 * sizeof(uint32_t));
+    }
+
+    i = bank_number(old_mode);
+    env->banked_r13[i] = env->regs[13];
+    env->banked_r14[i] = env->regs[14];
+    env->banked_spsr[i] = env->spsr;
+
+    i = bank_number(mode);
+    env->regs[13] = env->banked_r13[i];
+    env->regs[14] = env->banked_r14[i];
+    env->spsr = env->banked_spsr[i];
+}
+
+/* Handle a CPU exception.  */
+void do_interrupt(CPUARMState *env)
+{
+    uint32_t addr;
+    uint32_t mask;
+    int new_mode;
+    uint32_t offset;
+
+    /* TODO: Vectored interrupt controller.  */
+    switch (env->exception_index) {
+    case EXCP_UDEF:
+        new_mode = ARM_CPU_MODE_UND;
+        addr = 0x04;
+        mask = CPSR_I;
+        if (env->thumb)
+            offset = 2;
+        else
+            offset = 4;
+        break;
+    case EXCP_SWI:
+        new_mode = ARM_CPU_MODE_SVC;
+        addr = 0x08;
+        mask = CPSR_I;
+        /* The PC already points to the next instructon.  */
+        offset = 0;
+        break;
+    case EXCP_PREFETCH_ABORT:
+        new_mode = ARM_CPU_MODE_ABT;
+        addr = 0x0c;
+        mask = CPSR_A | CPSR_I;
+        offset = 4;
+        break;
+    case EXCP_DATA_ABORT:
+        new_mode = ARM_CPU_MODE_ABT;
+        addr = 0x10;
+        mask = CPSR_A | CPSR_I;
+        offset = 8;
+        break;
+    case EXCP_IRQ:
+        new_mode = ARM_CPU_MODE_IRQ;
+        addr = 0x18;
+        /* Disable IRQ and imprecise data aborts.  */
+        mask = CPSR_A | CPSR_I;
+        offset = 4;
+        break;
+    case EXCP_FIQ:
+        new_mode = ARM_CPU_MODE_FIQ;
+        addr = 0x1c;
+        /* Disable FIQ, IRQ and imprecise data aborts.  */
+        mask = CPSR_A | CPSR_I | CPSR_F;
+        offset = 4;
+        break;
+    default:
+        cpu_abort(env, "Unhandled exception 0x%x\n", env->exception_index);
+        return; /* Never happens.  Keep compiler happy.  */
+    }
+    /* High vectors.  */
+    if (env->cp15.c1_sys & (1 << 13)) {
+        addr += 0xffff0000;
+    }
+    switch_mode (env, new_mode);
+    env->spsr = cpsr_read(env);
+    /* Switch to the new mode, and clear the thumb bit.  */
+    /* ??? Thumb interrupt handlers not implemented.  */
+    env->uncached_cpsr = (env->uncached_cpsr & ~(CPSR_M | CPSR_T)) | new_mode;
+    env->uncached_cpsr |= mask;
+    env->regs[14] = env->regs[15] + offset;
+    env->regs[15] = addr;
+    env->interrupt_request |= CPU_INTERRUPT_EXITTB;
+}
+
+/* Check section/page access permissions.
+   Returns the page protection flags, or zero if the access is not
+   permitted.  */
+static inline int check_ap(CPUState *env, int ap, int domain, int access_type,
+                           int is_user)
+{
+  if (domain == 3)
+    return PAGE_READ | PAGE_WRITE;
+
+  switch (ap) {
+  case 0:
+      if (access_type != 1)
+          return 0;
+      switch ((env->cp15.c1_sys >> 8) & 3) {
+      case 1:
+          return is_user ? 0 : PAGE_READ;
+      case 2:
+          return PAGE_READ;
+      default:
+          return 0;
+      }
+  case 1:
+      return is_user ? 0 : PAGE_READ | PAGE_WRITE;
+  case 2:
+      if (is_user)
+          return (access_type == 1) ? 0 : PAGE_READ;
+      else
+          return PAGE_READ | PAGE_WRITE;
+  case 3:
+      return PAGE_READ | PAGE_WRITE;
+  default:
+      abort();
+  }
+}
+
+static int get_phys_addr(CPUState *env, uint32_t address, int access_type,
+                         int is_user, uint32_t *phys_ptr, int *prot)
+{
+    int code;
+    uint32_t table;
+    uint32_t desc;
+    int type;
+    int ap;
+    int domain;
+    uint32_t phys_addr;
+
+    /* Fast Context Switch Extension.  */
+    if (address < 0x02000000)
+        address += env->cp15.c13_fcse;
+
+    if ((env->cp15.c1_sys & 1) == 0) {
+        /* MMU diusabled.  */
+        *phys_ptr = address;
+        *prot = PAGE_READ | PAGE_WRITE;
+    } else {
+        /* Pagetable walk.  */
+        /* Lookup l1 descriptor.  */
+        table = (env->cp15.c2 & 0xffffc000) | ((address >> 18) & 0x3ffc);
+        desc = ldl_phys(table);
+        type = (desc & 3);
+        domain = (env->cp15.c3 >> ((desc >> 4) & 0x1e)) & 3;
+        if (type == 0) {
+            /* Secton translation fault.  */
+            code = 5;
+            goto do_fault;
+        }
+        if (domain == 0 || domain == 2) {
+            if (type == 2)
+                code = 9; /* Section domain fault.  */
+            else
+                code = 11; /* Page domain fault.  */
+            goto do_fault;
+        }
+        if (type == 2) {
+            /* 1Mb section.  */
+            phys_addr = (desc & 0xfff00000) | (address & 0x000fffff);
+            ap = (desc >> 10) & 3;
+            code = 13;
+        } else {
+            /* Lookup l2 entry.  */
+            table = (desc & 0xfffffc00) | ((address >> 10) & 0x3fc);
+            desc = ldl_phys(table);
+            switch (desc & 3) {
+            case 0: /* Page translation fault.  */
+                code = 7;
+                goto do_fault;
+            case 1: /* 64k page.  */
+                phys_addr = (desc & 0xffff0000) | (address & 0xffff);
+                ap = (desc >> (4 + ((address >> 13) & 6))) & 3;
+                break;
+            case 2: /* 4k page.  */
+                phys_addr = (desc & 0xfffff000) | (address & 0xfff);
+                ap = (desc >> (4 + ((address >> 13) & 6))) & 3;
+                break;
+            case 3: /* 1k page.  */
+                if (type == 1) {
+                    /* Page translation fault.  */
+                    code = 7;
+                    goto do_fault;
+                }
+                phys_addr = (desc & 0xfffffc00) | (address & 0x3ff);
+                ap = (desc >> 4) & 3;
+                break;
+            default:
+                /* Never happens, but compiler isn't smart enough to tell.  */
+                abort();
+            }
+            code = 15;
+        }
+        *prot = check_ap(env, ap, domain, access_type, is_user);
+        if (!*prot) {
+            /* Access permission fault.  */
+            goto do_fault;
+        }
+        *phys_ptr = phys_addr;
+    }
+    return 0;
+do_fault:
+    return code | (domain << 4);
+}
+
+int cpu_arm_handle_mmu_fault (CPUState *env, target_ulong address,
+                              int access_type, int is_user, int is_softmmu)
+{
+    uint32_t phys_addr;
+    int prot;
+    int ret;
+
+    ret = get_phys_addr(env, address, access_type, is_user, &phys_addr, &prot);
+    if (ret == 0) {
+        /* Map a single [sub]page.  */
+        phys_addr &= ~(uint32_t)0x3ff;
+        address &= ~(uint32_t)0x3ff;
+        return tlb_set_page (env, address, phys_addr, prot, is_user,
+                             is_softmmu);
+    }
+
+    if (access_type == 2) {
+        env->cp15.c5_insn = ret;
+        env->cp15.c6_insn = address;
+        env->exception_index = EXCP_PREFETCH_ABORT;
+    } else {
+        env->cp15.c5_data = ret;
+        env->cp15.c6_data = address;
+        env->exception_index = EXCP_DATA_ABORT;
+    }
+    return 1;
+}
+
+target_ulong cpu_get_phys_page_debug(CPUState *env, target_ulong addr)
+{
+    uint32_t phys_addr;
+    int prot;
+    int ret;
+
+    ret = get_phys_addr(env, addr, 0, 0, &phys_addr, &prot);
+
+    if (ret != 0)
+        return -1;
+
+    return phys_addr;
+}
+
+void helper_set_cp15(CPUState *env, uint32_t insn, uint32_t val)
+{
+    uint32_t op2;
+
+    op2 = (insn >> 5) & 7;
+    switch ((insn >> 16) & 0xf) {
+    case 0: /* ID codes.  */
+        goto bad_reg;
+    case 1: /* System configuration.  */
+        switch (op2) {
+        case 0:
+            env->cp15.c1_sys = val;
+            /* ??? Lots of these bits are not implemented.  */
+            /* This may enable/disable the MMU, so do a TLB flush.  */
+            tlb_flush(env, 1);
+            break;
+        case 2:
+            env->cp15.c1_coproc = val;
+            /* ??? Is this safe when called from within a TB?  */
+            tb_flush(env);
+        default:
+            goto bad_reg;
+        }
+        break;
+    case 2: /* MMU Page table control.  */
+        env->cp15.c2 = val;
+        break;
+    case 3: /* MMU Domain access control.  */
+        env->cp15.c3 = val;
+        break;
+    case 4: /* Reserved.  */
+        goto bad_reg;
+    case 5: /* MMU Fault status.  */
+        switch (op2) {
+        case 0:
+            env->cp15.c5_data = val;
+            break;
+        case 1:
+            env->cp15.c5_insn = val;
+            break;
+        default:
+            goto bad_reg;
+        }
+        break;
+    case 6: /* MMU Fault address.  */
+        switch (op2) {
+        case 0:
+            env->cp15.c6_data = val;
+            break;
+        case 1:
+            env->cp15.c6_insn = val;
+            break;
+        default:
+            goto bad_reg;
+        }
+        break;
+    case 7: /* Cache control.  */
+        /* No cache, so nothing to do.  */
+        break;
+    case 8: /* MMU TLB control.  */
+        switch (op2) {
+        case 0: /* Invalidate all.  */
+            tlb_flush(env, 0);
+            break;
+        case 1: /* Invalidate single TLB entry.  */
+#if 0
+            /* ??? This is wrong for large pages and sections.  */
+            /* As an ugly hack to make linux work we always flush a 4K
+               pages.  */
+            val &= 0xfffff000;
+            tlb_flush_page(env, val);
+            tlb_flush_page(env, val + 0x400);
+            tlb_flush_page(env, val + 0x800);
+            tlb_flush_page(env, val + 0xc00);
+#else
+            tlb_flush(env, 1);
+#endif
+            break;
+        default:
+            goto bad_reg;
+        }
+        break;
+    case 9: /* Cache lockdown.  */
+        switch (op2) {
+        case 0:
+            env->cp15.c9_data = val;
+            break;
+        case 1:
+            env->cp15.c9_insn = val;
+            break;
+        default:
+            goto bad_reg;
+        }
+        break;
+    case 10: /* MMU TLB lockdown.  */
+        /* ??? TLB lockdown not implemented.  */
+        break;
+    case 11: /* TCM DMA control.  */
+    case 12: /* Reserved.  */
+        goto bad_reg;
+    case 13: /* Process ID.  */
+        switch (op2) {
+        case 0:
+            env->cp15.c9_data = val;
+            break;
+        case 1:
+            env->cp15.c9_insn = val;
+            break;
+        default:
+            goto bad_reg;
+        }
+        break;
+    case 14: /* Reserved.  */
+        goto bad_reg;
+    case 15: /* Implementation specific.  */
+        /* ??? Internal registers not implemented.  */
+        break;
+    }
+    return;
+bad_reg:
+    /* ??? For debugging only.  Should raise illegal instruction exception.  */
+    cpu_abort(env, "Unimplemented cp15 register read\n");
+}
+
+uint32_t helper_get_cp15(CPUState *env, uint32_t insn)
+{
+    uint32_t op2;
+
+    op2 = (insn >> 5) & 7;
+    switch ((insn >> 16) & 0xf) {
+    case 0: /* ID codes.  */
+        switch (op2) {
+        default: /* Device ID.  */
+            return 0x4106a262;
+        case 1: /* Cache Type.  */
+            return 0x1dd20d2;
+        case 2: /* TCM status.  */
+            return 0;
+        }
+    case 1: /* System configuration.  */
+        switch (op2) {
+        case 0: /* Control register.  */
+            return env->cp15.c1_sys;
+        case 1: /* Auxiliary control register.  */
+            return 1;
+        case 2: /* Coprocessor access register.  */
+            return env->cp15.c1_coproc;
+        default:
+            goto bad_reg;
+        }
+    case 2: /* MMU Page table control.  */
+        return env->cp15.c2;
+    case 3: /* MMU Domain access control.  */
+        return env->cp15.c3;
+    case 4: /* Reserved.  */
+        goto bad_reg;
+    case 5: /* MMU Fault status.  */
+        switch (op2) {
+        case 0:
+            return env->cp15.c5_data;
+        case 1:
+            return env->cp15.c5_insn;
+        default:
+            goto bad_reg;
+        }
+    case 6: /* MMU Fault address.  */
+        switch (op2) {
+        case 0:
+            return env->cp15.c6_data;
+        case 1:
+            return env->cp15.c6_insn;
+        default:
+            goto bad_reg;
+        }
+    case 7: /* Cache control.  */
+        /* ??? This is for test, clean and invaidate operations that set the
+           Z flag.  We can't represent N = Z = 1, so it also clears clears
+           the N flag.  Oh well.  */
+        env->NZF = 0;
+        return 0;
+    case 8: /* MMU TLB control.  */
+        goto bad_reg;
+    case 9: /* Cache lockdown.  */
+        switch (op2) {
+        case 0:
+            return env->cp15.c9_data;
+        case 1:
+            return env->cp15.c9_insn;
+        default:
+            goto bad_reg;
+        }
+    case 10: /* MMU TLB lockdown.  */
+        /* ??? TLB lockdown not implemented.  */
+        return 0;
+    case 11: /* TCM DMA control.  */
+    case 12: /* Reserved.  */
+        goto bad_reg;
+    case 13: /* Process ID.  */
+        switch (op2) {
+        case 0:
+            return env->cp15.c13_fcse;
+        case 1:
+            return env->cp15.c13_context;
+        default:
+            goto bad_reg;
+        }
+    case 14: /* Reserved.  */
+        goto bad_reg;
+    case 15: /* Implementation specific.  */
+        /* ??? Internal registers not implemented.  */
+        return 0;
+    }
+bad_reg:
+    /* ??? For debugging only.  Should raise illegal instruction exception.  */
+    cpu_abort(env, "Unimplemented cp15 register read\n");
+    return 0;
+}
+
+#endif