target/arm: Always pass cacheattr to get_phys_addr

We need to check the memattr of a page in order to determine
whether it is Tagged for MTE.  Between Stage1 and Stage2,
this becomes simpler if we always collect this data, instead
of occasionally being presented with NULL.

Use the nonnull attribute to allow the compiler to check that
all pointer arguments are non-null.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200626033144.790098-42-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

4 files changed, 42 insertions, 36 deletions

diff --git a/target/arm/helper.c b/target/arm/helper.c
index d220612..2072db2 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -44,7 +44,8 @@ static bool get_phys_addr_lpae(CPUARMState *env, target_ulong address,
                                bool s1_is_el0,
                                hwaddr *phys_ptr, MemTxAttrs *txattrs, int *prot,
                                target_ulong *page_size_ptr,
-                               ARMMMUFaultInfo *fi, ARMCacheAttrs *cacheattrs);
+                               ARMMMUFaultInfo *fi, ARMCacheAttrs *cacheattrs)
+    __attribute__((nonnull));
 #endif
 
 static void switch_mode(CPUARMState *env, int mode);
@@ -11101,19 +11102,16 @@ static bool get_phys_addr_lpae(CPUARMState *env, target_ulong address,
         arm_tlb_bti_gp(txattrs) = true;
     }
 
-    if (cacheattrs != NULL) {
-        if (mmu_idx == ARMMMUIdx_Stage2) {
-            cacheattrs->attrs = convert_stage2_attrs(env,
-                                                     extract32(attrs, 0, 4));
-        } else {
-            /* Index into MAIR registers for cache attributes */
-            uint8_t attrindx = extract32(attrs, 0, 3);
-            uint64_t mair = env->cp15.mair_el[regime_el(env, mmu_idx)];
-            assert(attrindx <= 7);
-            cacheattrs->attrs = extract64(mair, attrindx * 8, 8);
-        }
-        cacheattrs->shareability = extract32(attrs, 6, 2);
+    if (mmu_idx == ARMMMUIdx_Stage2) {
+        cacheattrs->attrs = convert_stage2_attrs(env, extract32(attrs, 0, 4));
+    } else {
+        /* Index into MAIR registers for cache attributes */
+        uint8_t attrindx = extract32(attrs, 0, 3);
+        uint64_t mair = env->cp15.mair_el[regime_el(env, mmu_idx)];
+        assert(attrindx <= 7);
+        cacheattrs->attrs = extract64(mair, attrindx * 8, 8);
     }
+    cacheattrs->shareability = extract32(attrs, 6, 2);
 
     *phys_ptr = descaddr;
     *page_size_ptr = page_size;
@@ -11948,28 +11946,29 @@ bool get_phys_addr(CPUARMState *env, target_ulong address,
             ret = get_phys_addr_lpae(env, ipa, access_type, ARMMMUIdx_Stage2,
                                      mmu_idx == ARMMMUIdx_E10_0,
                                      phys_ptr, attrs, &s2_prot,
-                                     page_size, fi,
-                                     cacheattrs != NULL ? &cacheattrs2 : NULL);
+                                     page_size, fi, &cacheattrs2);
             fi->s2addr = ipa;
             /* Combine the S1 and S2 perms.  */
             *prot &= s2_prot;
 
-            /* Combine the S1 and S2 cache attributes, if needed */
-            if (!ret && cacheattrs != NULL) {
-                if (env->cp15.hcr_el2 & HCR_DC) {
-                    /*
-                     * HCR.DC forces the first stage attributes to
-                     *  Normal Non-Shareable,
-                     *  Inner Write-Back Read-Allocate Write-Allocate,
-                     *  Outer Write-Back Read-Allocate Write-Allocate.
-                     */
-                    cacheattrs->attrs = 0xff;
-                    cacheattrs->shareability = 0;
-                }
-                *cacheattrs = combine_cacheattrs(*cacheattrs, cacheattrs2);
+            /* If S2 fails, return early.  */
+            if (ret) {
+                return ret;
             }
 
-            return ret;
+            /* Combine the S1 and S2 cache attributes. */
+            if (env->cp15.hcr_el2 & HCR_DC) {
+                /*
+                 * HCR.DC forces the first stage attributes to
+                 *  Normal Non-Shareable,
+                 *  Inner Write-Back Read-Allocate Write-Allocate,
+                 *  Outer Write-Back Read-Allocate Write-Allocate.
+                 */
+                cacheattrs->attrs = 0xff;
+                cacheattrs->shareability = 0;
+            }
+            *cacheattrs = combine_cacheattrs(*cacheattrs, cacheattrs2);
+            return 0;
         } else {
             /*
              * For non-EL2 CPUs a stage1+stage2 translation is just stage 1.
@@ -12094,11 +12093,12 @@ hwaddr arm_cpu_get_phys_page_attrs_debug(CPUState *cs, vaddr addr,
     bool ret;
     ARMMMUFaultInfo fi = {};
     ARMMMUIdx mmu_idx = arm_mmu_idx(env);
+    ARMCacheAttrs cacheattrs = {};
 
     *attrs = (MemTxAttrs) {};
 
     ret = get_phys_addr(env, addr, 0, mmu_idx, &phys_addr,
-                        attrs, &prot, &page_size, &fi, NULL);
+                        attrs, &prot, &page_size, &fi, &cacheattrs);
 
     if (ret) {
         return -1;
diff --git a/target/arm/internals.h b/target/arm/internals.h
index 3306c4f..ae99725 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -1294,7 +1294,8 @@ bool get_phys_addr(CPUARMState *env, target_ulong address,
                    MMUAccessType access_type, ARMMMUIdx mmu_idx,
                    hwaddr *phys_ptr, MemTxAttrs *attrs, int *prot,
                    target_ulong *page_size,
-                   ARMMMUFaultInfo *fi, ARMCacheAttrs *cacheattrs);
+                   ARMMMUFaultInfo *fi, ARMCacheAttrs *cacheattrs)
+    __attribute__((nonnull));
 
 void arm_log_exception(int idx);
 
diff --git a/target/arm/m_helper.c b/target/arm/m_helper.c
index 5e8a795..0364542 100644
--- a/target/arm/m_helper.c
+++ b/target/arm/m_helper.c
@@ -187,12 +187,13 @@ static bool v7m_stack_write(ARMCPU *cpu, uint32_t addr, uint32_t value,
     hwaddr physaddr;
     int prot;
     ARMMMUFaultInfo fi = {};
+    ARMCacheAttrs cacheattrs = {};
     bool secure = mmu_idx & ARM_MMU_IDX_M_S;
     int exc;
     bool exc_secure;
 
     if (get_phys_addr(env, addr, MMU_DATA_STORE, mmu_idx, &physaddr,
-                      &attrs, &prot, &page_size, &fi, NULL)) {
+                      &attrs, &prot, &page_size, &fi, &cacheattrs)) {
         /* MPU/SAU lookup failed */
         if (fi.type == ARMFault_QEMU_SFault) {
             if (mode == STACK_LAZYFP) {
@@ -279,13 +280,14 @@ static bool v7m_stack_read(ARMCPU *cpu, uint32_t *dest, uint32_t addr,
     hwaddr physaddr;
     int prot;
     ARMMMUFaultInfo fi = {};
+    ARMCacheAttrs cacheattrs = {};
     bool secure = mmu_idx & ARM_MMU_IDX_M_S;
     int exc;
     bool exc_secure;
     uint32_t value;
 
     if (get_phys_addr(env, addr, MMU_DATA_LOAD, mmu_idx, &physaddr,
-                      &attrs, &prot, &page_size, &fi, NULL)) {
+                      &attrs, &prot, &page_size, &fi, &cacheattrs)) {
         /* MPU/SAU lookup failed */
         if (fi.type == ARMFault_QEMU_SFault) {
             qemu_log_mask(CPU_LOG_INT,
@@ -1928,6 +1930,7 @@ static bool v7m_read_half_insn(ARMCPU *cpu, ARMMMUIdx mmu_idx,
     V8M_SAttributes sattrs = {};
     MemTxAttrs attrs = {};
     ARMMMUFaultInfo fi = {};
+    ARMCacheAttrs cacheattrs = {};
     MemTxResult txres;
     target_ulong page_size;
     hwaddr physaddr;
@@ -1945,8 +1948,8 @@ static bool v7m_read_half_insn(ARMCPU *cpu, ARMMMUIdx mmu_idx,
                       "...really SecureFault with SFSR.INVEP\n");
         return false;
     }
-    if (get_phys_addr(env, addr, MMU_INST_FETCH, mmu_idx,
-                      &physaddr, &attrs, &prot, &page_size, &fi, NULL)) {
+    if (get_phys_addr(env, addr, MMU_INST_FETCH, mmu_idx, &physaddr,
+                      &attrs, &prot, &page_size, &fi, &cacheattrs)) {
         /* the MPU lookup failed */
         env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_IACCVIOL_MASK;
         armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_MEM, env->v7m.secure);
diff --git a/target/arm/tlb_helper.c b/target/arm/tlb_helper.c
index 522a644..89d9046 100644
--- a/target/arm/tlb_helper.c
+++ b/target/arm/tlb_helper.c
@@ -166,6 +166,7 @@ bool arm_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
     int prot, ret;
     MemTxAttrs attrs = {};
     ARMMMUFaultInfo fi = {};
+    ARMCacheAttrs cacheattrs = {};
 
     /*
      * Walk the page table and (if the mapping exists) add the page
@@ -175,7 +176,8 @@ bool arm_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
      */
     ret = get_phys_addr(&cpu->env, address, access_type,
                         core_to_arm_mmu_idx(&cpu->env, mmu_idx),
-                        &phys_addr, &attrs, &prot, &page_size, &fi, NULL);
+                        &phys_addr, &attrs, &prot, &page_size,
+                        &fi, &cacheattrs);
     if (likely(!ret)) {
         /*
          * Map a single [sub]page. Regions smaller than our declared