[PATCH v2 10/17] linux-user/aarch64: Implement PR_MTE_TCF and PR_MTE_TAG

[Richard Henderson]

These prctl fields are required for the function of MTE.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/aarch64/target_syscall.h |  9 ++++++
 linux-user/syscall.c                | 46 +++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)

diff --git a/linux-user/aarch64/target_syscall.h 
b/linux-user/aarch64/target_syscall.h
index 5fb0bf4a5d..779ca0c805 100644
--- a/linux-user/aarch64/target_syscall.h
+++ b/linux-user/aarch64/target_syscall.h
@@ -32,5 +32,14 @@ struct target_pt_regs {
 #define TARGET_PR_SET_TAGGED_ADDR_CTRL 55
 #define TARGET_PR_GET_TAGGED_ADDR_CTRL 56
 # define TARGET_PR_TAGGED_ADDR_ENABLE  (1UL << 0)
+/* MTE tag check fault modes */
+# define TARGET_PR_MTE_TCF_SHIFT       1
+# define TARGET_PR_MTE_TCF_NONE        (0UL << TARGET_PR_MTE_TCF_SHIFT)
+# define TARGET_PR_MTE_TCF_SYNC        (1UL << TARGET_PR_MTE_TCF_SHIFT)
+# define TARGET_PR_MTE_TCF_ASYNC       (2UL << TARGET_PR_MTE_TCF_SHIFT)
+# define TARGET_PR_MTE_TCF_MASK        (3UL << TARGET_PR_MTE_TCF_SHIFT)
+/* MTE tag inclusion mask */
+# define TARGET_PR_MTE_TAG_SHIFT       3
+# define TARGET_PR_MTE_TAG_MASK        (0xffffUL << TARGET_PR_MTE_TAG_SHIFT)
 
 #endif /* AARCH64_TARGET_SYSCALL_H */
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index e4da53c5b3..9cf3ce872d 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -10463,10 +10463,47 @@ static abi_long do_syscall1(void *cpu_env, int num, 
abi_long arg1,
         case TARGET_PR_SET_TAGGED_ADDR_CTRL:
             {
                 abi_ulong valid_mask = TARGET_PR_TAGGED_ADDR_ENABLE;
+                CPUARMState *env = cpu_env;
+                ARMCPU *cpu = env_archcpu(env);
+
+                if (cpu_isar_feature(aa64_mte, cpu)) {
+                    valid_mask |= TARGET_PR_MTE_TCF_MASK;
+                    valid_mask |= TARGET_PR_MTE_TAG_MASK;
+                }
 
                 if ((arg2 & ~valid_mask) || arg3 || arg4 || arg5) {
                     return -TARGET_EINVAL;
                 }
+
+                if (cpu_isar_feature(aa64_mte, cpu)) {
+                    switch (arg2 & TARGET_PR_MTE_TCF_MASK) {
+                    case TARGET_PR_MTE_TCF_NONE:
+                    case TARGET_PR_MTE_TCF_SYNC:
+                    case TARGET_PR_MTE_TCF_ASYNC:
+                        break;
+                    default:
+                        return -EINVAL;
+                    }
+
+                    /*
+                     * Write PR_MTE_TCF to SCTLR_EL1[TCF0].
+                     * Note that the syscall values are consistent with hw.
+                     */
+                    env->cp15.sctlr_el[1] =
+                        deposit64(env->cp15.sctlr_el[1], 38, 2,
+                                  arg2 >> TARGET_PR_MTE_TCF_SHIFT);
+
+                    /*
+                     * Write PR_MTE_TAG to GCR_EL1[Exclude].
+                     * Note that the syscall uses an include mask,
+                     * and hardware uses an exclude mask -- invert.
+                     */
+                    env->cp15.gcr_el1 =
+                        deposit64(env->cp15.gcr_el1, 0, 16,
+                                  ~arg2 >> TARGET_PR_MTE_TAG_SHIFT);
+                    arm_rebuild_hflags(env);
+                }
+
                 untagged_addr_mask = (arg2 & TARGET_PR_TAGGED_ADDR_ENABLE
                                       ? MAKE_64BIT_MASK(0, 56) : -1);
                 return 0;
@@ -10474,6 +10511,8 @@ static abi_long do_syscall1(void *cpu_env, int num, 
abi_long arg1,
         case TARGET_PR_GET_TAGGED_ADDR_CTRL:
             {
                 abi_long ret = 0;
+                CPUARMState *env = cpu_env;
+                ARMCPU *cpu = env_archcpu(env);
 
                 if (arg2 || arg3 || arg4 || arg5) {
                     return -TARGET_EINVAL;
@@ -10481,6 +10520,13 @@ static abi_long do_syscall1(void *cpu_env, int num, 
abi_long arg1,
                 if (~untagged_addr_mask != 0) {
                     ret |= TARGET_PR_TAGGED_ADDR_ENABLE;
                 }
+                if (cpu_isar_feature(aa64_mte, cpu)) {
+                    /* See above. */
+                    ret |= (extract64(env->cp15.sctlr_el[1], 38, 2)
+                            << TARGET_PR_MTE_TCF_SHIFT);
+                    ret = deposit64(ret, TARGET_PR_MTE_TAG_SHIFT, 16,
+                                    ~env->cp15.gcr_el1);
+                }
                 return ret;
             }
 #endif /* AARCH64 */
-- 
2.25.1