svc_exports.h

00001 /*
00002  * Copyright (c) 2013-2016, ARM Limited, All Rights Reserved
00003  * SPDX-License-Identifier: Apache-2.0
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License"); you may
00006  * not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  * http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
00013  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 #ifndef __UVISOR_API_SVC_EXPORTS_H__
00018 #define __UVISOR_API_SVC_EXPORTS_H__
00019 
00020 #include "api/inc/uvisor_exports.h"
00021 #include "api/inc/api.h"
00022 #include <stdint.h>
00023 
00024 /* An SVCall takes a 8bit immediate, which is used as follows:
00025  *
00026  * For fast APIs:
00027  *
00028  *   7   6   5   4   3   2   1   0
00029  * .---.---.---.---.---.---.---.---.
00030  * | 1 | N | N | N | h | h | h | h |
00031  * '---'---'---'---'---'---'---'---'
00032  *   |   |_______|   |___________|
00033  *   |       |         |
00034  *   |       |         |
00035  *   |       |         |
00036  *   |       |        (h) Handler index in the hardcoded table (max 16)
00037  *   |       |
00038  *   |      (N) Number of arguments to pass to the handler (max 4)
00039  *   |
00040  *   SVCall mode: Fast
00041  *
00042  * For slow APIs:
00043  *
00044  *   7   6   5   4   3   2   1   0
00045  * .---.---.---.---.---.---.---.---.
00046  * | 0 | c | c | c | c | c | c | c |
00047  * '---'---'---'---'---'---'---'---'
00048  *   |   |_______________________|
00049  *   |               |
00050  *   |               |
00051  *   |              (c) Handler index in the custom table (max 128)
00052  *   |
00053  *   SVCall mode: Slow
00054  */
00055 
00056 /* 1 bit of the SVCall imm8 field is used to determine the mode, fast/slow. */
00057 #define UVISOR_SVC_MODE_FAST  1
00058 #define UVISOR_SVC_MODE_SLOW  0
00059 #define UVISOR_SVC_MODE_BIT   7
00060 #define UVISOR_SVC_MODE_MASK  ((uint8_t) (1 << UVISOR_SVC_MODE_BIT))
00061 #define UVISOR_SVC_MODE(mode) ((uint8_t) (((mode) << UVISOR_SVC_MODE_BIT) & UVISOR_SVC_MODE_MASK))
00062 
00063 /* 7 or 4 bits of the SVCall imm8 field are used to determine the table index,
00064  * depending on the mode, fast/slow. */
00065 #define UVISOR_SVC_FAST_INDEX_MAX  (1 << 4)
00066 #define UVISOR_SVC_SLOW_INDEX_MAX  (1 << 7)
00067 #define UVISOR_SVC_FAST_INDEX_BIT  0
00068 #define UVISOR_SVC_FAST_INDEX_MASK ((uint8_t) (0xF << UVISOR_SVC_FAST_INDEX_BIT))
00069 #define UVISOR_SVC_SLOW_INDEX_BIT  0
00070 #define UVISOR_SVC_SLOW_INDEX_MASK ((uint8_t) (0x7F << UVISOR_SVC_SLOW_INDEX_BIT))
00071 #define UVISOR_SVC_FAST_INDEX(index) ((uint8_t) (((index) << UVISOR_SVC_FAST_INDEX_BIT) & UVISOR_SVC_FAST_INDEX_MASK))
00072 #define UVISOR_SVC_SLOW_INDEX(index) ((uint8_t) (((index) << UVISOR_SVC_SLOW_INDEX_BIT) & UVISOR_SVC_SLOW_INDEX_MASK))
00073 
00074 /* When the SVC mode is "fast", the imm8 field also contains a specification of
00075  * the call interface (number of arguments).
00076  * This is needed for context switches, since the stack manipulation routines
00077  * need to know how many arguments to copy from source to destination. */
00078 #define UVISOR_SVC_FAST_NARGS_BIT         4
00079 #define UVISOR_SVC_FAST_NARGS_MASK        ((uint8_t) (0x7 << UVISOR_SVC_FAST_NARGS_BIT))
00080 #define UVISOR_SVC_FAST_NARGS_SET(nargs)  ((uint8_t) (((nargs) << UVISOR_SVC_FAST_NARGS_BIT) & UVISOR_SVC_FAST_NARGS_MASK))
00081 #define UVISOR_SVC_FAST_NARGS_GET(svc_id) (((uint8_t) (svc_id) & UVISOR_SVC_FAST_NARGS_MASK) >> UVISOR_SVC_FAST_NARGS_BIT)
00082 
00083 /* Macros to build the SVCall imm8 field.
00084  * For slow APIs only the SVC handler index is needed.
00085  * For fast APIs the SVC handler index and the number of arguments are needed. */
00086 #define UVISOR_SVC_CUSTOM_TABLE(index) ((uint8_t) (UVISOR_SVC_MODE(UVISOR_SVC_MODE_SLOW) | \
00087                                                    UVISOR_SVC_SLOW_INDEX(index)))
00088 #define UVISOR_SVC_FIXED_TABLE(index, nargs) ((uint8_t) (UVISOR_SVC_MODE(UVISOR_SVC_MODE_FAST) | \
00089                                                          UVISOR_SVC_FAST_INDEX(index) | \
00090                                                          UVISOR_SVC_FAST_NARGS_SET(nargs)))
00091 
00092 /* SVC immediate values for hardcoded table (call from unprivileged) */
00093 #define UVISOR_SVC_ID_UNVIC_OUT           UVISOR_SVC_FIXED_TABLE(0, 0)
00094 /* Deprecated: UVISOR_SVC_ID_CX_IN(nargs) UVISOR_SVC_FIXED_TABLE(1, nargs) */
00095 /* Deprecated: UVISOR_SVC_ID_CX_OUT       UVISOR_SVC_FIXED_TABLE(2, 0) */
00096 #define UVISOR_SVC_ID_REGISTER_GATEWAY    UVISOR_SVC_FIXED_TABLE(3, 0)
00097 #define UVISOR_SVC_ID_BOX_INIT_FIRST      UVISOR_SVC_FIXED_TABLE(4, 0)
00098 #define UVISOR_SVC_ID_BOX_INIT_NEXT       UVISOR_SVC_FIXED_TABLE(5, 0)
00099 
00100 /* SVC immediate values for hardcoded table (call from privileged) */
00101 #define UVISOR_SVC_ID_UNVIC_IN         UVISOR_SVC_FIXED_TABLE(0, 0)
00102 
00103 #endif /* __UVISOR_API_SVC_EXPORTS_H__ */