qemu

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

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