2 files changed, 34 insertions, 0 deletions
diff --git a/target/arm/cpu-param.h b/target/arm/cpu-param.h
index 00e7d9e937..7f38d33b8e 100644
--- a/target/arm/cpu-param.h
+++ b/target/arm/cpu-param.h
@@ -20,6 +20,9 @@
 
 #ifdef CONFIG_USER_ONLY
 #define TARGET_PAGE_BITS 12
+# ifdef TARGET_AARCH64
+#  define TARGET_TAGGED_ADDRESSES
+# endif
 #else
 /*
  * ARMv7 and later CPUs have 4K pages minimum, but ARMv5 and v6
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index f240275407..72a0819eb8 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -721,6 +721,11 @@ typedef struct CPUARMState {
     const struct arm_boot_info *boot_info;
     /* Store GICv3CPUState to access from this struct */
     void *gicv3state;
+
+#ifdef TARGET_TAGGED_ADDRESSES
+    /* Linux syscall tagged address support */
+    bool tagged_addr_enable;
+#endif
 } CPUARMState;
 
 static inline void set_feature(CPUARMState *env, int feature)
@@ -3604,6 +3609,32 @@ static inline MemTxAttrs *typecheck_memtxattrs(MemTxAttrs *x)
  */
 #define PAGE_BTI  PAGE_TARGET_1
 
+#ifdef TARGET_TAGGED_ADDRESSES
+/**
+ * cpu_untagged_addr:
+ * @cs: CPU context
+ * @x: tagged address
+ *
+ * Remove any address tag from @x.  This is explicitly related to the
+ * linux syscall TIF_TAGGED_ADDR setting, not TBI in general.
+ *
+ * There should be a better place to put this, but we need this in
+ * include/exec/cpu_ldst.h, and not some place linux-user specific.
+ */
+static inline target_ulong cpu_untagged_addr(CPUState *cs, target_ulong x)
+{
+    ARMCPU *cpu = ARM_CPU(cs);
+    if (cpu->env.tagged_addr_enable) {
+        /*
+         * TBI is enabled for userspace but not kernelspace addresses.
+         * Only clear the tag if bit 55 is clear.
+         */
+        x &= sextract64(x, 0, 56);
+    }
+    return x;
+}
+#endif
+
 /*
  * Naming convention for isar_feature functions:
  * Functions which test 32-bit ID registers should have _aa32_ in