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Antonio Nino Diaz3c817f42018-03-21 10:49:27 +00001/*
2 * Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7#ifndef __SMCCC_HELPERS_H__
8#define __SMCCC_HELPERS_H__
9
10#include <smccc.h>
11
12/* These are offsets to registers in smc_ctx_t */
Antonio Nino Diazf0b14cf2018-10-04 09:55:23 +010013#define SMC_CTX_GPREG_R0 U(0x0)
14#define SMC_CTX_GPREG_R1 U(0x4)
15#define SMC_CTX_GPREG_R2 U(0x8)
16#define SMC_CTX_GPREG_R3 U(0xC)
17#define SMC_CTX_GPREG_R4 U(0x10)
18#define SMC_CTX_GPREG_R5 U(0x14)
19#define SMC_CTX_SP_USR U(0x34)
20#define SMC_CTX_SPSR_MON U(0x78)
21#define SMC_CTX_SP_MON U(0x7C)
22#define SMC_CTX_LR_MON U(0x80)
23#define SMC_CTX_SCR U(0x84)
24#define SMC_CTX_PMCR U(0x88)
25#define SMC_CTX_SIZE U(0x90)
Antonio Nino Diaz3c817f42018-03-21 10:49:27 +000026
27#ifndef __ASSEMBLY__
28#include <cassert.h>
Antonio Nino Diaz4b32e622018-08-16 16:52:57 +010029#include <stdint.h>
Antonio Nino Diaz3c817f42018-03-21 10:49:27 +000030
31/*
32 * The generic structure to save arguments and callee saved registers during
33 * an SMC. Also this structure is used to store the result return values after
34 * the completion of SMC service.
35 */
36typedef struct smc_ctx {
37 u_register_t r0;
38 u_register_t r1;
39 u_register_t r2;
40 u_register_t r3;
41 u_register_t r4;
42 u_register_t r5;
43 u_register_t r6;
44 u_register_t r7;
45 u_register_t r8;
46 u_register_t r9;
47 u_register_t r10;
48 u_register_t r11;
49 u_register_t r12;
50 /* spsr_usr doesn't exist */
51 u_register_t sp_usr;
52 u_register_t lr_usr;
53 u_register_t spsr_irq;
54 u_register_t sp_irq;
55 u_register_t lr_irq;
56 u_register_t spsr_fiq;
57 u_register_t sp_fiq;
58 u_register_t lr_fiq;
59 u_register_t spsr_svc;
60 u_register_t sp_svc;
61 u_register_t lr_svc;
62 u_register_t spsr_abt;
63 u_register_t sp_abt;
64 u_register_t lr_abt;
65 u_register_t spsr_und;
66 u_register_t sp_und;
67 u_register_t lr_und;
68 u_register_t spsr_mon;
69 /*
70 * `sp_mon` will point to the C runtime stack in monitor mode. But prior
71 * to exit from SMC, this will point to the `smc_ctx_t` so that
72 * on next entry due to SMC, the `smc_ctx_t` can be easily accessed.
73 */
74 u_register_t sp_mon;
75 u_register_t lr_mon;
76 u_register_t scr;
77 u_register_t pmcr;
78 /*
79 * The workaround for CVE-2017-5715 requires storing information in
80 * the bottom 3 bits of the stack pointer. Add a padding field to
81 * force the size of the struct to be a multiple of 8.
82 */
83 u_register_t pad;
84} smc_ctx_t __aligned(8);
85
86/*
87 * Compile time assertions related to the 'smc_context' structure to
88 * ensure that the assembler and the compiler view of the offsets of
89 * the structure members is the same.
90 */
91CASSERT(SMC_CTX_GPREG_R0 == __builtin_offsetof(smc_ctx_t, r0), \
92 assert_smc_ctx_greg_r0_offset_mismatch);
93CASSERT(SMC_CTX_GPREG_R1 == __builtin_offsetof(smc_ctx_t, r1), \
94 assert_smc_ctx_greg_r1_offset_mismatch);
95CASSERT(SMC_CTX_GPREG_R2 == __builtin_offsetof(smc_ctx_t, r2), \
96 assert_smc_ctx_greg_r2_offset_mismatch);
97CASSERT(SMC_CTX_GPREG_R3 == __builtin_offsetof(smc_ctx_t, r3), \
98 assert_smc_ctx_greg_r3_offset_mismatch);
99CASSERT(SMC_CTX_GPREG_R4 == __builtin_offsetof(smc_ctx_t, r4), \
100 assert_smc_ctx_greg_r4_offset_mismatch);
101CASSERT(SMC_CTX_SP_USR == __builtin_offsetof(smc_ctx_t, sp_usr), \
102 assert_smc_ctx_sp_usr_offset_mismatch);
103CASSERT(SMC_CTX_LR_MON == __builtin_offsetof(smc_ctx_t, lr_mon), \
104 assert_smc_ctx_lr_mon_offset_mismatch);
105CASSERT(SMC_CTX_SPSR_MON == __builtin_offsetof(smc_ctx_t, spsr_mon), \
106 assert_smc_ctx_spsr_mon_offset_mismatch);
107
Antonio Nino Diazf0b14cf2018-10-04 09:55:23 +0100108CASSERT((sizeof(smc_ctx_t) & 0x7U) == 0U, assert_smc_ctx_not_aligned);
Antonio Nino Diaz3c817f42018-03-21 10:49:27 +0000109CASSERT(SMC_CTX_SIZE == sizeof(smc_ctx_t), assert_smc_ctx_size_mismatch);
110
111/* Convenience macros to return from SMC handler */
112#define SMC_RET0(_h) { \
113 return (uintptr_t)(_h); \
114}
115#define SMC_RET1(_h, _r0) { \
116 ((smc_ctx_t *)(_h))->r0 = (_r0); \
117 SMC_RET0(_h); \
118}
119#define SMC_RET2(_h, _r0, _r1) { \
120 ((smc_ctx_t *)(_h))->r1 = (_r1); \
121 SMC_RET1(_h, (_r0)); \
122}
123#define SMC_RET3(_h, _r0, _r1, _r2) { \
124 ((smc_ctx_t *)(_h))->r2 = (_r2); \
125 SMC_RET2(_h, (_r0), (_r1)); \
126}
127#define SMC_RET4(_h, _r0, _r1, _r2, _r3) { \
128 ((smc_ctx_t *)(_h))->r3 = (_r3); \
129 SMC_RET3(_h, (_r0), (_r1), (_r2)); \
130}
131
Antonio Nino Diaz3c817f42018-03-21 10:49:27 +0000132/*
133 * Helper macro to retrieve the SMC parameters from smc_ctx_t.
134 */
135#define get_smc_params_from_ctx(_hdl, _r1, _r2, _r3, _r4) { \
136 _r1 = ((smc_ctx_t *)_hdl)->r1; \
137 _r2 = ((smc_ctx_t *)_hdl)->r2; \
138 _r3 = ((smc_ctx_t *)_hdl)->r3; \
139 _r4 = ((smc_ctx_t *)_hdl)->r4; \
140 }
141
142/* ------------------------------------------------------------------------
143 * Helper APIs for setting and retrieving appropriate `smc_ctx_t`.
144 * These functions need to implemented by the BL including this library.
145 * ------------------------------------------------------------------------
146 */
147
148/* Get the pointer to `smc_ctx_t` corresponding to the security state. */
149void *smc_get_ctx(unsigned int security_state);
150
151/* Set the next `smc_ctx_t` corresponding to the security state. */
152void smc_set_next_ctx(unsigned int security_state);
153
154/* Get the pointer to next `smc_ctx_t` already set by `smc_set_next_ctx()`. */
155void *smc_get_next_ctx(void);
156
157#endif /*__ASSEMBLY__*/
158
159#endif /* __SMCCC_HELPERS_H__ */