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.wfi_wfe_branch = 0;
45     m_instr_info.instr_addr = 0;
46     m_instr_info.opcode = 0;
47     m_pMemAccess = 0;
48     m_pIDecode = 0;
49     m_mem_space_csid = 0;
50     m_st_range_addr =  m_en_range_addr = m_next_addr = 0;
51     m_b_next_valid = false;
52     m_b_nacc_err = false;
53 }
54 
55 OcsdCodeFollower::~OcsdCodeFollower()
56 {
57 }
58 
59 void OcsdCodeFollower::initInterfaces(componentAttachPt<ITargetMemAccess> *pMemAccess, componentAttachPt<IInstrDecode> *pIDecode)
60 {
61     m_pMemAccess = pMemAccess;
62     m_pIDecode = pIDecode;
63 }
64 
65 bool OcsdCodeFollower::initFollowerState()
66 {
67     bool initDone = false;
68 
69     // reset per follow flags
70     m_b_next_valid = false;
71     m_b_nacc_err = false;
72 
73     // set range addresses
74     m_en_range_addr = m_next_addr = m_st_range_addr;
75 
76 // check initialisation is valid.
77 
78     // must have attached memory access and i-decode objects
79     if(m_pMemAccess && m_pIDecode)
80     {
81         initDone = (m_pMemAccess->hasAttachedAndEnabled() && m_pIDecode->hasAttachedAndEnabled());
82     }
83     return initDone;
84 }
85 
86 /*!
87  * Decodes an instruction at a single location, calculates the next address
88  * if possible according to the instruction type and atom.
89  *
90  * @param addrStart : Address of the instruction
91  * @param A :  Atom value - E or N
92  *
93  * @return ocsd_err_t : OCSD_OK - decode correct, check flags for next address
94  *                    : OCSD_ERR_MEM_NACC - unable to access memory area @ address - need new address in trace packet stream.
95  *                    : OCSD_ERR_NOT_INIT - not initialised - fatal.
96  *                    : OCSD_<other>  - other error occured - fatal.
97  */
98 ocsd_err_t OcsdCodeFollower::followSingleAtom(const ocsd_vaddr_t addrStart, const ocsd_atm_val A)
99 {
100     ocsd_err_t err = OCSD_ERR_NOT_INIT;
101 
102     if(!initFollowerState())
103         return err;
104 
105     m_en_range_addr = m_st_range_addr = m_instr_info.instr_addr = addrStart;
106     err = decodeSingleOpCode();
107 
108     if(err != OCSD_OK)
109         return err;
110 
111     // set end range - always after the instruction executed.
112     m_en_range_addr = m_instr_info.instr_addr + m_instr_info.instr_size;
113 
114     // assume next addr is the instruction after
115     m_next_addr = m_en_range_addr;
116     m_b_next_valid = true;
117 
118     // case when next address is different
119     switch(m_instr_info.type)
120     {
121     case OCSD_INSTR_BR:
122         if(A == ATOM_E) // executed the direct branch
123             m_next_addr = m_instr_info.branch_addr;
124         break;
125 
126     case OCSD_INSTR_BR_INDIRECT:
127         if(A == ATOM_E) // executed indirect branch
128             m_b_next_valid = false;
129         break;
130     }
131     return err;
132 }
133 
134 ocsd_err_t OcsdCodeFollower::decodeSingleOpCode()
135 {
136     ocsd_err_t err = OCSD_OK;
137     // request 4 bytes for the opcode - even for Thumb which may be T32
138     uint32_t bytesReq = 4;
139     uint32_t opcode;    // buffer for opcode
140 
141     // read memory location for opcode
142     err = m_pMemAccess->first()->ReadTargetMemory(m_instr_info.instr_addr,m_mem_space_csid,m_mem_acc_rule,&bytesReq,(uint8_t *)&opcode);
143 
144     // operational error (not access problem - that is indicated by 0 bytes returned)
145     if(err != OCSD_OK)
146         return err;
147 
148     if(bytesReq == 4)       // check that we got all memory requested.
149     {
150         m_instr_info.opcode = opcode;
151         err = m_pIDecode->first()->DecodeInstruction(&m_instr_info);
152     }
153     else       // otherwise memory unavailable.
154     {
155         m_b_nacc_err = true;
156         m_nacc_address = m_instr_info.instr_addr;
157         err = OCSD_ERR_MEM_NACC;
158     }
159     return err;
160 }
161 
162 /* End of File ocsd_code_follower.cpp */
163