target/arm/tcg/tlb_helper.c

   1 /*
   2  * ARM TLB (Translation lookaside buffer) helpers.
   3  *
   4  * This code is licensed under the GNU GPL v2 or later.
   5  *
   6  * SPDX-License-Identifier: GPL-2.0-or-later
   7  */
   8 #include "qemu/osdep.h"
   9 #include "cpu.h"
  10 #include "internals.h"
  11 #include "exec/exec-all.h"
  12 #include "exec/helper-proto.h"
  13
  14
  15 /*
  16  * Returns true if the stage 1 translation regime is using LPAE format page
  17  * tables. Used when raising alignment exceptions, whose FSR changes depending
  18  * on whether the long or short descriptor format is in use.
  19  */
  20 bool arm_s1_regime_using_lpae_format(CPUARMState *env, ARMMMUIdx mmu_idx)
  21 {
  22     mmu_idx = stage_1_mmu_idx(mmu_idx);
  23     return regime_using_lpae_format(env, mmu_idx);
  24 }
  25
  26 static inline uint32_t merge_syn_data_abort(uint32_t template_syn,
  27                                             ARMMMUFaultInfo *fi,
  28                                             unsigned int target_el,
  29                                             bool same_el, bool is_write,
  30                                             int fsc)
  31 {
  32     uint32_t syn;
  33
  34     /*
  35      * ISV is only set for stage-2 data aborts routed to EL2 and
  36      * never for stage-1 page table walks faulting on stage 2
  37      * or for stage-1 faults.
  38      *
  39      * Furthermore, ISV is only set for certain kinds of load/stores.
  40      * If the template syndrome does not have ISV set, we should leave
  41      * it cleared.
  42      *
  43      * See ARMv8 specs, D7-1974:
  44      * ISS encoding for an exception from a Data Abort, the
  45      * ISV field.
  46      *
  47      * TODO: FEAT_LS64/FEAT_LS64_V/FEAT_SL64_ACCDATA: Translation,
  48      * Access Flag, and Permission faults caused by LD64B, ST64B,
  49      * ST64BV, or ST64BV0 insns report syndrome info even for stage-1
  50      * faults and regardless of the target EL.
  51      */
  52     if (!(template_syn & ARM_EL_ISV) || target_el != 2
  53         || fi->s1ptw || !fi->stage2) {
  54         syn = syn_data_abort_no_iss(same_el, 0,
  55                                     fi->ea, 0, fi->s1ptw, is_write, fsc);
  56     } else {
  57         /*
  58          * Fields: IL, ISV, SAS, SSE, SRT, SF and AR come from the template
  59          * syndrome created at translation time.
  60          * Now we create the runtime syndrome with the remaining fields.
  61          */
  62         syn = syn_data_abort_with_iss(same_el,
  63                                       0, 0, 0, 0, 0,
  64                                       fi->ea, 0, fi->s1ptw, is_write, fsc,
  65                                       true);
  66         /* Merge the runtime syndrome with the template syndrome.  */
  67         syn |= template_syn;
  68     }
  69     return syn;
  70 }
  71
  72 static uint32_t compute_fsr_fsc(CPUARMState *env, ARMMMUFaultInfo *fi,
  73                                 int target_el, int mmu_idx, uint32_t *ret_fsc)
  74 {
  75     ARMMMUIdx arm_mmu_idx = core_to_arm_mmu_idx(env, mmu_idx);
  76     uint32_t fsr, fsc;
  77
  78     /*
  79      * For M-profile there is no guest-facing FSR. We compute a
  80      * short-form value for env->exception.fsr which we will then
  81      * examine in arm_v7m_cpu_do_interrupt(). In theory we could
  82      * use the LPAE format instead as long as both bits of code agree
  83      * (and arm_fi_to_lfsc() handled the M-profile specific
  84      * ARMFault_QEMU_NSCExec and ARMFault_QEMU_SFault cases).
  85      */
  86     if (!arm_feature(env, ARM_FEATURE_M) &&
  87         (target_el == 2 || arm_el_is_aa64(env, target_el) ||
  88          arm_s1_regime_using_lpae_format(env, arm_mmu_idx))) {
  89         /*
  90          * LPAE format fault status register : bottom 6 bits are
  91          * status code in the same form as needed for syndrome
  92          */
  93         fsr = arm_fi_to_lfsc(fi);
  94         fsc = extract32(fsr, 0, 6);
  95     } else {
  96         fsr = arm_fi_to_sfsc(fi);
  97         /*
  98          * Short format FSR : this fault will never actually be reported
  99          * to an EL that uses a syndrome register. Use a (currently)
 100          * reserved FSR code in case the constructed syndrome does leak
 101          * into the guest somehow.
 102          */
 103         fsc = 0x3f;
 104     }
 105
 106     *ret_fsc = fsc;
 107     return fsr;
 108 }
 109
 110 static G_NORETURN
 111 void arm_deliver_fault(ARMCPU *cpu, vaddr addr,
 112                        MMUAccessType access_type,
 113                        int mmu_idx, ARMMMUFaultInfo *fi)
 114 {
 115     CPUARMState *env = &cpu->env;
 116     int target_el;
 117     bool same_el;
 118     uint32_t syn, exc, fsr, fsc;
 119
 120     target_el = exception_target_el(env);
 121     if (fi->stage2) {
 122         target_el = 2;
 123         env->cp15.hpfar_el2 = extract64(fi->s2addr, 12, 47) << 4;
 124         if (arm_is_secure_below_el3(env) && fi->s1ns) {
 125             env->cp15.hpfar_el2 |= HPFAR_NS;
 126         }
 127     }
 128     same_el = (arm_current_el(env) == target_el);
 129
 130     fsr = compute_fsr_fsc(env, fi, target_el, mmu_idx, &fsc);
 131
 132     if (access_type == MMU_INST_FETCH) {
 133         syn = syn_insn_abort(same_el, fi->ea, fi->s1ptw, fsc);
 134         exc = EXCP_PREFETCH_ABORT;
 135     } else {
 136         syn = merge_syn_data_abort(env->exception.syndrome, fi, target_el,
 137                                    same_el, access_type == MMU_DATA_STORE,
 138                                    fsc);
 139         if (access_type == MMU_DATA_STORE
 140             && arm_feature(env, ARM_FEATURE_V6)) {
 141             fsr |= (1 << 11);
 142         }
 143         exc = EXCP_DATA_ABORT;
 144     }
 145
 146     env->exception.vaddress = addr;
 147     env->exception.fsr = fsr;
 148     raise_exception(env, exc, syn, target_el);
 149 }
 150
 151 /* Raise a data fault alignment exception for the specified virtual address */
 152 void arm_cpu_do_unaligned_access(CPUState *cs, vaddr vaddr,
 153                                  MMUAccessType access_type,
 154                                  int mmu_idx, uintptr_t retaddr)
 155 {
 156     ARMCPU *cpu = ARM_CPU(cs);
 157     ARMMMUFaultInfo fi = {};
 158
 159     /* now we have a real cpu fault */
 160     cpu_restore_state(cs, retaddr);
 161
 162     fi.type = ARMFault_Alignment;
 163     arm_deliver_fault(cpu, vaddr, access_type, mmu_idx, &fi);
 164 }
 165
 166 void helper_exception_pc_alignment(CPUARMState *env, target_ulong pc)
 167 {
 168     ARMMMUFaultInfo fi = { .type = ARMFault_Alignment };
 169     int target_el = exception_target_el(env);
 170     int mmu_idx = cpu_mmu_index(env, true);
 171     uint32_t fsc;
 172
 173     env->exception.vaddress = pc;
 174
 175     /*
 176      * Note that the fsc is not applicable to this exception,
 177      * since any syndrome is pcalignment not insn_abort.
 178      */
 179     env->exception.fsr = compute_fsr_fsc(env, &fi, target_el, mmu_idx, &fsc);
 180     raise_exception(env, EXCP_PREFETCH_ABORT, syn_pcalignment(), target_el);
 181 }
 182
 183 #if !defined(CONFIG_USER_ONLY)
 184
 185 /*
 186  * arm_cpu_do_transaction_failed: handle a memory system error response
 187  * (eg "no device/memory present at address") by raising an external abort
 188  * exception
 189  */
 190 void arm_cpu_do_transaction_failed(CPUState *cs, hwaddr physaddr,
 191                                    vaddr addr, unsigned size,
 192                                    MMUAccessType access_type,
 193                                    int mmu_idx, MemTxAttrs attrs,
 194                                    MemTxResult response, uintptr_t retaddr)
 195 {
 196     ARMCPU *cpu = ARM_CPU(cs);
 197     ARMMMUFaultInfo fi = {};
 198
 199     /* now we have a real cpu fault */
 200     cpu_restore_state(cs, retaddr);
 201
 202     fi.ea = arm_extabort_type(response);
 203     fi.type = ARMFault_SyncExternal;
 204     arm_deliver_fault(cpu, addr, access_type, mmu_idx, &fi);
 205 }
 206
 207 bool arm_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
 208                       MMUAccessType access_type, int mmu_idx,
 209                       bool probe, uintptr_t retaddr)
 210 {
 211     ARMCPU *cpu = ARM_CPU(cs);
 212     GetPhysAddrResult res = {};
 213     ARMMMUFaultInfo local_fi, *fi;
 214     int ret;
 215
 216     /*
 217      * Allow S1_ptw_translate to see any fault generated here.
 218      * Since this may recurse, read and clear.
 219      */
 220     fi = cpu->env.tlb_fi;
 221     if (fi) {
 222         cpu->env.tlb_fi = NULL;
 223     } else {
 224         fi = memset(&local_fi, 0, sizeof(local_fi));
 225     }
 226
 227     /*
 228      * Walk the page table and (if the mapping exists) add the page
 229      * to the TLB.  On success, return true.  Otherwise, if probing,
 230      * return false.  Otherwise populate fsr with ARM DFSR/IFSR fault
 231      * register format, and signal the fault.
 232      */
 233     ret = get_phys_addr(&cpu->env, address, access_type,
 234                         core_to_arm_mmu_idx(&cpu->env, mmu_idx),
 235                         &res, fi);
 236     if (likely(!ret)) {
 237         /*
 238          * Map a single [sub]page. Regions smaller than our declared
 239          * target page size are handled specially, so for those we
 240          * pass in the exact addresses.
 241          */
 242         if (res.f.lg_page_size >= TARGET_PAGE_BITS) {
 243             res.f.phys_addr &= TARGET_PAGE_MASK;
 244             address &= TARGET_PAGE_MASK;
 245         }
 246
 247         res.f.pte_attrs = res.cacheattrs.attrs;
 248         res.f.shareability = res.cacheattrs.shareability;
 249
 250         tlb_set_page_full(cs, mmu_idx, address, &res.f);
 251         return true;
 252     } else if (probe) {
 253         return false;
 254     } else {
 255         /* now we have a real cpu fault */
 256         cpu_restore_state(cs, retaddr);
 257         arm_deliver_fault(cpu, address, access_type, mmu_idx, fi);
 258     }
 259 }
 260 #else
 261 void arm_cpu_record_sigsegv(CPUState *cs, vaddr addr,
 262                             MMUAccessType access_type,
 263                             bool maperr, uintptr_t ra)
 264 {
 265     ARMMMUFaultInfo fi = {
 266         .type = maperr ? ARMFault_Translation : ARMFault_Permission,
 267         .level = 3,
 268     };
 269     ARMCPU *cpu = ARM_CPU(cs);
 270
 271     /*
 272      * We report both ESR and FAR to signal handlers.
 273      * For now, it's easiest to deliver the fault normally.
 274      */
 275     cpu_restore_state(cs, ra);
 276     arm_deliver_fault(cpu, addr, access_type, MMU_USER_IDX, &fi);
 277 }
 278
 279 void arm_cpu_record_sigbus(CPUState *cs, vaddr addr,
 280                            MMUAccessType access_type, uintptr_t ra)
 281 {
 282     arm_cpu_do_unaligned_access(cs, addr, access_type, MMU_USER_IDX, ra);
 283 }
 284 #endif /* !defined(CONFIG_USER_ONLY) */