1 /*
2 * Copyright (c) 2021-2025, Arm Limited and Contributors. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7 #include <stdbool.h>
8
9 #include <arch.h>
10 #include <arch_features.h>
11 #include <arch_helpers.h>
12 #include <common/debug.h>
13 #include <lib/el3_runtime/context_mgmt.h>
14 #include <lib/extensions/sme.h>
15 #include <lib/extensions/sve.h>
16
sme_enable(cpu_context_t * context)17 void sme_enable(cpu_context_t *context)
18 {
19 u_register_t reg;
20 el3_state_t *state;
21
22 /* Get the context state. */
23 state = get_el3state_ctx(context);
24
25 /* Set the ENTP2 bit in SCR_EL3 to enable access to TPIDR2_EL0. */
26 reg = read_ctx_reg(state, CTX_SCR_EL3);
27 reg |= SCR_ENTP2_BIT;
28 write_ctx_reg(state, CTX_SCR_EL3, reg);
29 }
30
sme_enable_per_world(per_world_context_t * per_world_ctx)31 void sme_enable_per_world(per_world_context_t *per_world_ctx)
32 {
33 u_register_t reg;
34
35 /* Enable SME in CPTR_EL3. */
36 reg = per_world_ctx->ctx_cptr_el3;
37 reg |= ESM_BIT;
38 per_world_ctx->ctx_cptr_el3 = reg;
39 }
40
sme_init_el3(void)41 void sme_init_el3(void)
42 {
43 u_register_t smcr_el3;
44
45 /*
46 * Set the max LEN value and FA64 bit. This register is set up per_world
47 * to be the least restrictive, then lower ELs can restrict as needed
48 * using SMCR_EL2 and SMCR_EL1.
49 */
50 smcr_el3 = SMCR_ELX_LEN_MAX;
51 if (is_feat_sme_fa64_present()) {
52 VERBOSE("[SME] FA64 enabled\n");
53 smcr_el3 |= SMCR_ELX_FA64_BIT;
54 }
55
56 /*
57 * Enable access to ZT0 register.
58 * Make sure FEAT_SME2 is supported by the hardware before continuing.
59 * If supported, Set the EZT0 bit in SMCR_EL3 to allow instructions to
60 * access ZT0 register without trapping.
61 */
62 if (is_feat_sme2_supported()) {
63 VERBOSE("SME2 enabled\n");
64 smcr_el3 |= SMCR_ELX_EZT0_BIT;
65 }
66 write_smcr_el3(smcr_el3);
67 }
68
sme_init_el2_unused(void)69 void sme_init_el2_unused(void)
70 {
71 /*
72 * CPTR_EL2.TCPAC: Set to zero so that Non-secure EL1 accesses to the
73 * CPACR_EL1 or CPACR from both Execution states do not trap to EL2.
74 */
75 write_cptr_el2(read_cptr_el2() & ~CPTR_EL2_TCPAC_BIT);
76 }
77
sme_disable(cpu_context_t * context)78 void sme_disable(cpu_context_t *context)
79 {
80 u_register_t reg;
81 el3_state_t *state;
82
83 /* Get the context state. */
84 state = get_el3state_ctx(context);
85
86 /* Disable access to TPIDR2_EL0. */
87 reg = read_ctx_reg(state, CTX_SCR_EL3);
88 reg &= ~SCR_ENTP2_BIT;
89 write_ctx_reg(state, CTX_SCR_EL3, reg);
90 }
91
sme_disable_per_world(per_world_context_t * per_world_ctx)92 void sme_disable_per_world(per_world_context_t *per_world_ctx)
93 {
94 u_register_t reg;
95
96 /* Disable SME, SVE, and FPU since they all share registers. */
97 reg = per_world_ctx->ctx_cptr_el3;
98 reg &= ~ESM_BIT; /* Trap SME */
99 reg &= ~CPTR_EZ_BIT; /* Trap SVE */
100 per_world_ctx->ctx_cptr_el3 = reg;
101 }
102