[PATCH v9 42/46] target/arm: Cache the Tagged bit for a page in MemTxAttrs

[Richard Henderson]

This "bit" is a particular value of the page's MemAttr.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
v6: Test HCR_EL2.{DC,DCT}; test Stage2 attributes.
v8: Fill in cacheattrs for S1 disabled; retain tagging when
    combining attributes; set mte_tagging in arm_cpu_tlb_fill.
---
 target/arm/helper.c     | 48 ++++++++++++++++++++++++++++++++++++++---
 target/arm/tlb_helper.c |  5 +++++
 2 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 2072db2f92..dc9c29f998 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -11834,9 +11834,19 @@ static uint8_t combine_cacheattr_nibble(uint8_t s1, 
uint8_t s2)
  */
 static ARMCacheAttrs combine_cacheattrs(ARMCacheAttrs s1, ARMCacheAttrs s2)
 {
-    uint8_t s1lo = extract32(s1.attrs, 0, 4), s2lo = extract32(s2.attrs, 0, 4);
-    uint8_t s1hi = extract32(s1.attrs, 4, 4), s2hi = extract32(s2.attrs, 4, 4);
+    uint8_t s1lo, s2lo, s1hi, s2hi;
     ARMCacheAttrs ret;
+    bool tagged = false;
+
+    if (s1.attrs == 0xf0) {
+        tagged = true;
+        s1.attrs = 0xff;
+    }
+
+    s1lo = extract32(s1.attrs, 0, 4);
+    s2lo = extract32(s2.attrs, 0, 4);
+    s1hi = extract32(s1.attrs, 4, 4);
+    s2hi = extract32(s2.attrs, 4, 4);
 
     /* Combine shareability attributes (table D4-43) */
     if (s1.shareability == 2 || s2.shareability == 2) {
@@ -11884,6 +11894,11 @@ static ARMCacheAttrs combine_cacheattrs(ARMCacheAttrs 
s1, ARMCacheAttrs s2)
         }
     }
 
+    /* TODO: CombineS1S2Desc does not consider transient, only WB, RWA. */
+    if (tagged && ret.attrs == 0xff) {
+        ret.attrs = 0xf0;
+    }
+
     return ret;
 }
 
@@ -11963,8 +11978,11 @@ bool get_phys_addr(CPUARMState *env, target_ulong 
address,
                  *  Normal Non-Shareable,
                  *  Inner Write-Back Read-Allocate Write-Allocate,
                  *  Outer Write-Back Read-Allocate Write-Allocate.
+                 * Do not overwrite Tagged within attrs.
                  */
-                cacheattrs->attrs = 0xff;
+                if (cacheattrs->attrs != 0xf0) {
+                    cacheattrs->attrs = 0xff;
+                }
                 cacheattrs->shareability = 0;
             }
             *cacheattrs = combine_cacheattrs(*cacheattrs, cacheattrs2);
@@ -12029,6 +12047,9 @@ bool get_phys_addr(CPUARMState *env, target_ulong 
address,
     /* Definitely a real MMU, not an MPU */
 
     if (regime_translation_disabled(env, mmu_idx)) {
+        uint64_t hcr;
+        uint8_t memattr;
+
         /*
          * MMU disabled.  S1 addresses within aa64 translation regimes are
          * still checked for bounds -- see AArch64.TranslateAddressS1Off.
@@ -12066,6 +12087,27 @@ bool get_phys_addr(CPUARMState *env, target_ulong 
address,
         *phys_ptr = address;
         *prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
         *page_size = TARGET_PAGE_SIZE;
+
+        /* Fill in cacheattr a-la AArch64.TranslateAddressS1Off. */
+        hcr = arm_hcr_el2_eff(env);
+        cacheattrs->shareability = 0;
+        if (hcr & HCR_DC) {
+            if (hcr & HCR_DCT) {
+                memattr = 0xf0;  /* Tagged, Normal, WB, RWA */
+            } else {
+                memattr = 0xff;  /* Normal, WB, RWA */
+            }
+        } else if (access_type == MMU_INST_FETCH) {
+            if (regime_sctlr(env, mmu_idx) & SCTLR_I) {
+                memattr = 0xee;  /* Normal, WT, RA, NT */
+            } else {
+                memattr = 0x44;  /* Normal, NC, No */
+            }
+            cacheattrs->shareability = 2; /* outer sharable */
+        } else {
+            memattr = 0x00;      /* Device, nGnRnE */
+        }
+        cacheattrs->attrs = memattr;
         return 0;
     }
 
diff --git a/target/arm/tlb_helper.c b/target/arm/tlb_helper.c
index 89d90465a3..b35dc8a011 100644
--- a/target/arm/tlb_helper.c
+++ b/target/arm/tlb_helper.c
@@ -188,6 +188,11 @@ bool arm_cpu_tlb_fill(CPUState *cs, vaddr address, int 
size,
             phys_addr &= TARGET_PAGE_MASK;
             address &= TARGET_PAGE_MASK;
         }
+        /* Notice and record tagged memory. */
+        if (cpu_isar_feature(aa64_mte, cpu) && cacheattrs.attrs == 0xf0) {
+            arm_tlb_mte_tagged(&attrs) = true;
+        }
+
         tlb_set_page_with_attrs(cs, address, phys_addr, attrs,
                                 prot, mmu_idx, page_size);
         return true;
-- 
2.25.1