1 /*
2 * ARM MemTag convenience functions.
3 *
4 * This code is licensed under the GNU GPL v2 or later.
5 *
6 * SPDX-License-Identifier: LGPL-2.1-or-later
7 */
8
9 #include "qemu/osdep.h"
10 #include "qemu.h"
11 #include "mte_user_helper.h"
12
arm_set_mte_tcf0(CPUArchState * env,abi_long value)13 void arm_set_mte_tcf0(CPUArchState *env, abi_long value)
14 {
15 /*
16 * Write PR_MTE_TCF to SCTLR_EL1[TCF0].
17 *
18 * The kernel has a per-cpu configuration for the sysadmin,
19 * /sys/devices/system/cpu/cpu<N>/mte_tcf_preferred,
20 * which qemu does not implement.
21 *
22 * Because there is no performance difference between the modes, and
23 * because SYNC is most useful for debugging MTE errors, choose SYNC
24 * as the preferred mode. With this preference, and the way the API
25 * uses only two bits, there is no way for the program to select
26 * ASYMM mode.
27 */
28 unsigned tcf = 0;
29 if (value & PR_MTE_TCF_SYNC) {
30 tcf = 1;
31 } else if (value & PR_MTE_TCF_ASYNC) {
32 tcf = 2;
33 }
34 env->cp15.sctlr_el[1] = deposit64(env->cp15.sctlr_el[1], 38, 2, tcf);
35 }
36