[PATCH v3 20/21] target/arm: Enable MTE for user-only

[Richard Henderson]

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/cpu.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index abc0affd00..5e613a747a 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -208,6 +208,22 @@ static void arm_cpu_reset(DeviceState *dev)
          * Do not modify this without other changes.
          */
         env->cp15.tcr_el[1].raw_tcr = (3ULL << 37);
+
+        /* Enable MTE */
+        if (cpu_isar_feature(aa64_mte, cpu)) {
+            /* Enable tag access, but leave TCF0 as No Effect (0). */
+            env->cp15.sctlr_el[1] |= SCTLR_ATA0;
+            /*
+             * Exclude all tags, so that tag 0 is always used.
+             * This corresponds to Linux current->thread.gcr_incl = 0.
+             *
+             * Set RRND, so that helper_irg() will generate a seed later.
+             * Here in cpu_reset(), the crypto subsystem has not yet been
+             * initialized.
+             */
+            env->cp15.gcr_el1 = 0x1ffff;
+        }
+
 # ifdef TARGET_TAGGED_ADDRESSES
         env->untagged_addr_mask = -1;
 # endif
-- 
2.25.1