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