Factor out the code used for setting the MTE TCF0 field from the prctl
code into a convenient function. Other subsystems, like gdbstub, need to
set this field as well, so keep it as a separate function to avoid
duplication and ensure consistency in how this field is set across the
board.
Signed-off-by: Gustavo Romero <gustavo.rom...@linaro.org>
---
linux-user/aarch64/meson.build | 2 ++
linux-user/aarch64/mte_user_helper.c | 34 ++++++++++++++++++++++++++++
linux-user/aarch64/mte_user_helper.h | 25 ++++++++++++++++++++
linux-user/aarch64/target_prctl.h | 22 ++----------------
4 files changed, 63 insertions(+), 20 deletions(-)
create mode 100644 linux-user/aarch64/mte_user_helper.c
create mode 100644 linux-user/aarch64/mte_user_helper.h
diff --git a/linux-user/aarch64/meson.build b/linux-user/aarch64/meson.build
index 248c578d15..f75bb3cd75 100644
--- a/linux-user/aarch64/meson.build
+++ b/linux-user/aarch64/meson.build
@@ -9,3 +9,5 @@ vdso_le_inc = gen_vdso.process('vdso-le.so',
extra_args: ['-r', '__kernel_rt_sigreturn'])
linux_user_ss.add(when: 'TARGET_AARCH64', if_true: [vdso_be_inc, vdso_le_inc])
+
+linux_user_ss.add(when: 'TARGET_AARCH64', if_true:
[files('mte_user_helper.c')])
diff --git a/linux-user/aarch64/mte_user_helper.c
b/linux-user/aarch64/mte_user_helper.c
new file mode 100644
index 0000000000..8be6deaf03
--- /dev/null
+++ b/linux-user/aarch64/mte_user_helper.c
@@ -0,0 +1,34 @@
+/*
+ * ARM MemTag convenience functions.
+ *
+ * This code is licensed under the GNU GPL v2 or later.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
+#include <sys/prctl.h>
+#include "mte_user_helper.h"
+
+void arm_set_mte_tcf0(CPUArchState *env, abi_long value)
+{
+ /*
+ * Write PR_MTE_TCF to SCTLR_EL1[TCF0].
+ *
+ * The kernel has a per-cpu configuration for the sysadmin,
+ * /sys/devices/system/cpu/cpu<N>/mte_tcf_preferred,
+ * which qemu does not implement.
+ *
+ * Because there is no performance difference between the modes, and
+ * because SYNC is most useful for debugging MTE errors, choose SYNC
+ * as the preferred mode. With this preference, and the way the API
+ * uses only two bits, there is no way for the program to select
+ * ASYMM mode.
+ */
+ unsigned tcf = 0;
+ if (value & PR_MTE_TCF_SYNC) {
+ tcf = 1;
+ } else if (value & PR_MTE_TCF_ASYNC) {
+ tcf = 2;
+ }
+ env->cp15.sctlr_el[1] = deposit64(env->cp15.sctlr_el[1], 38, 2, tcf);
+}
diff --git a/linux-user/aarch64/mte_user_helper.h
b/linux-user/aarch64/mte_user_helper.h
new file mode 100644
index 0000000000..ee3f6b190a
--- /dev/null
+++ b/linux-user/aarch64/mte_user_helper.h
@@ -0,0 +1,25 @@
+/*
+ * ARM MemTag convenience functions.
+ *
+ * This code is licensed under the GNU GPL v2 or later.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
+#ifndef AARCH64_MTE_USER_HELPER_H
+#define AARCH64_MTE USER_HELPER_H
+
+#include "qemu/osdep.h"
+#include "qemu.h"
+
+/**
+ * arm_set_mte_tcf0 - Set TCF0 field in SCTLR_EL1 register
+ * @env: The CPU environment
+ * @value: The value to be set for the Tag Check Fault in EL0 field.
+ *
+ * Only SYNC and ASYNC modes can be selected. If ASYMM mode is given, the SYNC
+ * mode is selected instead. So, there is no way to set the ASYMM mode.
+ */
+void arm_set_mte_tcf0(CPUArchState *env, abi_long value);
+
+#endif /* AARCH64_MTE_USER_HELPER_H */
diff --git a/linux-user/aarch64/target_prctl.h
b/linux-user/aarch64/target_prctl.h
index aa8e203c15..ed75b9e4b5 100644
--- a/linux-user/aarch64/target_prctl.h
+++ b/linux-user/aarch64/target_prctl.h
@@ -7,6 +7,7 @@
#define AARCH64_TARGET_PRCTL_H
#include "target/arm/cpu-features.h"
+#include "mte_user_helper.h"
static abi_long do_prctl_sve_get_vl(CPUArchState *env)
{
@@ -173,26 +174,7 @@ static abi_long do_prctl_set_tagged_addr_ctrl(CPUArchState
*env, abi_long arg2)
env->tagged_addr_enable = arg2 & PR_TAGGED_ADDR_ENABLE;
if (cpu_isar_feature(aa64_mte, cpu)) {
- /*
- * Write PR_MTE_TCF to SCTLR_EL1[TCF0].
- *
- * The kernel has a per-cpu configuration for the sysadmin,
- * /sys/devices/system/cpu/cpu<N>/mte_tcf_preferred,
- * which qemu does not implement.
- *
- * Because there is no performance difference between the modes, and
- * because SYNC is most useful for debugging MTE errors, choose SYNC
- * as the preferred mode. With this preference, and the way the API
- * uses only two bits, there is no way for the program to select
- * ASYMM mode.
- */
- unsigned tcf = 0;
- if (arg2 & PR_MTE_TCF_SYNC) {
- tcf = 1;
- } else if (arg2 & PR_MTE_TCF_ASYNC) {
- tcf = 2;
- }
- env->cp15.sctlr_el[1] = deposit64(env->cp15.sctlr_el[1], 38, 2, tcf);
+ arm_set_mte_tcf0(env, arg2);
/*
* Write PR_MTE_TAG to GCR_EL1[Exclude].
--
2.34.1
