1 /*
2  * \file       ocsd_code_follower.cpp
3  * \brief      OpenCSD : Instruction Code path follower.
4  *
5  * \copyright  Copyright (c) 2016, ARM Limited. All Rights Reserved.
6  */
7 
8 
9 /*
10  * Redistribution and use in source and binary forms, with or without modification,
11  * are permitted provided that the following conditions are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright notice,
14  * this list of conditions and the following disclaimer.
15  *
16  * 2. Redistributions in binary form must reproduce the above copyright notice,
17  * this list of conditions and the following disclaimer in the documentation
18  * and/or other materials provided with the distribution.
19  *
20  * 3. Neither the name of the copyright holder nor the names of its contributors
21  * may be used to endorse or promote products derived from this software without
22  * specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 'AS IS' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
26  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27  * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
28  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
29  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
30  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
31  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34  */
35 
36 #include "common/ocsd_code_follower.h"
37 
38 OcsdCodeFollower::OcsdCodeFollower()
39 {
40     m_instr_info.pe_type.arch = ARCH_UNKNOWN;
41     m_instr_info.pe_type.profile = profile_Unknown;
42     m_instr_info.isa = ocsd_isa_unknown;
43     m_instr_info.dsb_dmb_waypoints = 0;
44     m_instr_info.instr_addr = 0;
45     m_instr_info.opcode = 0;
46     m_pMemAccess = 0;
47     m_pIDecode = 0;
48     m_mem_space_csid = 0;
49     m_st_range_addr =  m_en_range_addr = m_next_addr = 0;
50     m_b_next_valid = false;
51     m_b_nacc_err = false;
52 }
53 
54 OcsdCodeFollower::~OcsdCodeFollower()
55 {
56 }
57 
58 void OcsdCodeFollower::initInterfaces(componentAttachPt<ITargetMemAccess> *pMemAccess, componentAttachPt<IInstrDecode> *pIDecode)
59 {
60     m_pMemAccess = pMemAccess;
61     m_pIDecode = pIDecode;
62 }
63 
64 bool OcsdCodeFollower::initFollowerState()
65 {
66     bool initDone = false;
67 
68     // reset per follow flags
69     m_b_next_valid = false;
70     m_b_nacc_err = false;
71 
72     // set range addresses
73     m_en_range_addr = m_next_addr = m_st_range_addr;
74 
75 // check initialisation is valid.
76 
77     // must have attached memory access and i-decode objects
78     if(m_pMemAccess && m_pIDecode)
79     {
80         initDone = (m_pMemAccess->hasAttachedAndEnabled() && m_pIDecode->hasAttachedAndEnabled());
81     }
82     return initDone;
83 }
84 
85 /*!
86  * Decodes an instruction at a single location, calculates the next address
87  * if possible according to the instruction type and atom.
88  *
89  * @param addrStart : Address of the instruction
90  * @param A :  Atom value - E or N
91  *
92  * @return ocsd_err_t : OCSD_OK - decode correct, check flags for next address
93  *                    : OCSD_ERR_MEM_NACC - unable to access memory area @ address - need new address in trace packet stream.
94  *                    : OCSD_ERR_NOT_INIT - not initialised - fatal.
95  *                    : OCSD_<other>  - other error occured - fatal.
96  */
97 ocsd_err_t OcsdCodeFollower::followSingleAtom(const ocsd_vaddr_t addrStart, const ocsd_atm_val A)
98 {
99     ocsd_err_t err = OCSD_ERR_NOT_INIT;
100 
101     if(!initFollowerState())
102         return err;
103 
104     m_en_range_addr = m_st_range_addr = m_instr_info.instr_addr = addrStart;
105     err = decodeSingleOpCode();
106 
107     if(err != OCSD_OK)
108         return err;
109 
110     // set end range - always after the instruction executed.
111     m_en_range_addr = m_instr_info.instr_addr + m_instr_info.instr_size;
112 
113     // assume next addr is the instruction after
114     m_next_addr = m_en_range_addr;
115     m_b_next_valid = true;
116 
117     // case when next address is different
118     switch(m_instr_info.type)
119     {
120     case OCSD_INSTR_BR:
121         if(A == ATOM_E) // executed the direct branch
122             m_next_addr = m_instr_info.branch_addr;
123         break;
124 
125     case OCSD_INSTR_BR_INDIRECT:
126         if(A == ATOM_E) // executed indirect branch
127             m_b_next_valid = false;
128         break;
129     }
130     return err;
131 }
132 
133 ocsd_err_t OcsdCodeFollower::decodeSingleOpCode()
134 {
135     ocsd_err_t err = OCSD_OK;
136     // request 4 bytes for the opcode - even for Thumb which may be T32
137     uint32_t bytesReq = 4;
138     uint32_t opcode;    // buffer for opcode
139 
140     // read memory location for opcode
141     err = m_pMemAccess->first()->ReadTargetMemory(m_instr_info.instr_addr,m_mem_space_csid,m_mem_acc_rule,&bytesReq,(uint8_t *)&opcode);
142 
143     // operational error (not access problem - that is indicated by 0 bytes returned)
144     if(err != OCSD_OK)
145         return err;
146 
147     if(bytesReq == 4)       // check that we got all memory requested.
148     {
149         m_instr_info.opcode = opcode;
150         err = m_pIDecode->first()->DecodeInstruction(&m_instr_info);
151     }
152     else       // otherwise memory unavailable.
153     {
154         m_b_nacc_err = true;
155         m_nacc_address = m_instr_info.instr_addr;
156         err = OCSD_ERR_MEM_NACC;
157     }
158     return err;
159 }
160 
161 /* End of File ocsd_code_follower.cpp */
162