Memory alignment issues in Software Bus

[skliper]

The CFE code has some problem areas for CPUs that have strict memory alignment requirements (e.g. SPARC). Casting from a type with smaller requirements to a type with larger requirements generates a compile time warning and may induce a runtime exception if the memory actually is not aligned.

The following errors exist in the SB subsystem:

{{{
/cfe/fsw/cfe-core/src/sb/cfe_sb_api.c: In function 'CFE_SB_ZeroCopyGetPtr':
/cfe/fsw/cfe-core/src/sb/cfe_sb_api.c:1853:12: warning: cast increases required alignment of target type [-Wcast-align]
return (CFE_SB_Msg_t *)address;
^
/cfe/fsw/cfe-core/src/sb/cfe_sb_api.c: In function 'CFE_SB_ZeroCopyReleasePtr':
/cfe/fsw/cfe-core/src/sb/cfe_sb_api.c:1896:35: warning: cast increases required alignment of target type [-Wcast-align]
(uint32 *) (((uint8 *)Ptr2Release) - sizeof(CFE_SB_BufferD_t)));
^
/cfe/fsw/cfe-core/src/sb/cfe_sb_buf.c: In function 'CFE_SB_GetBufferFromCaller':
/cfe/fsw/cfe-core/src/sb/cfe_sb_buf.c:107:30: warning: cast increases required alignment of target type [-Wcast-align]
CFE_SB_BufferD_t *bd = (CFE_SB_BufferD_t *)(((uint8 *)Address) - sizeof(CFE_SB_BufferD_t));
^
/cfe/fsw/cfe-core/src/sb/cfe_sb_util.c: In function 'CFE_SB_GetMsgTime':
/cfe/fsw/cfe-core/src/sb/cfe_sb_util.c:280:21: warning: cast increases required alignment of target type [-Wcast-align]
TlmHdrPtr = (CFE_SB_TlmHdr_t *)MsgPtr;
^
/cfe/fsw/cfe-core/src/sb/cfe_sb_util.c: In function 'CFE_SB_SetMsgTime':
/cfe/fsw/cfe-core/src/sb/cfe_sb_util.c:345:21: warning: cast increases required alignment of target type [-Wcast-align]
TlmHdrPtr = (CFE_SB_TlmHdr_t *) MsgPtr;
^
}}}

NOTE: This is related to PSP ticket [cfs_psp:41]

[skliper]

Imported from trac issue 282. Created by jphickey on 2019-04-25T09:54:14, last modified: 2019-08-14T14:09:53

[CDKnightNASA]

One option I'm considering, aligning the pointer and then declaring it aligned: https://gcc.gnu.org/onlinedocs/gcc-3.3/gcc/Type-Attributes.html

[jphickey]

I thought I had a fix for at least some of these items..... let me check my un-merged branches.

In general I prefer to avoid anything compiler-specific unless absolutely necessary.

[CDKnightNASA]

Ok, thanks; I am curious how to fix it without a compiler directive. 😊 From: Joseph Hickey <notifications@github.com> Sent: Friday, January 3, 2020 07:07 To: nasa/cFE <cFE@noreply.github.com> Cc: Knight, Christopher D. (ARC-TI) <christopher.d.knight@nasa.gov>; Assign <assign@noreply.github.com> Subject: [EXTERNAL] Re: [nasa/cFE] Memory alignment issues in Software Bus (#313) I thought I had a fix for at least some of these items..... let me check my un-merged branches. In general I prefer to avoid anything compiler-specific unless absolutely necessary. — You are receiving this because you were assigned. Reply to this email directly, view it on GitHub<https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_nasa_cFE_issues_313-3Femail-5Fsource-3Dnotifications-26email-5Ftoken-3DAIZYMKYHDGBX4EPTTGLIW7TQ35IABA5CNFSM4I37NJD2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEIBKEUI-23issuecomment-2D570597969&d=DwMCaQ&c=ApwzowJNAKKw3xye91w7BE1XMRKi2LN9kiMk5Csz9Zk&r=JDJB_KO_kIJMmlWcOl5Br6wthfeLCcxzUseDoBjuvfFQOIpFSnwdteHjX4mn9USx&m=rEMA23RBApm1UQl5nDOpfo2W6YOvKzGaNG6RFSFTs-s&s=e3n-MKMEzZFKFkyruI0QcV55NOUWr3zqdTc_CcLgiqg&e=>, or unsubscribe<https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_notifications_unsubscribe-2Dauth_AIZYMKZXOZMTZYWPM2DERHLQ35IABANCNFSM4I37NJDQ&d=DwMCaQ&c=ApwzowJNAKKw3xye91w7BE1XMRKi2LN9kiMk5Csz9Zk&r=JDJB_KO_kIJMmlWcOl5Br6wthfeLCcxzUseDoBjuvfFQOIpFSnwdteHjX4mn9USx&m=rEMA23RBApm1UQl5nDOpfo2W6YOvKzGaNG6RFSFTs-s&s=2AD1jiOoq_pcAgZ8geZ9muzpr4Bp7Xy8CJcfZtNsK9c&e=>.

[jphickey]

My bad, I mistakenly wrote a new issue about this, not realizing that this one was already open - which is #437.

This doesn't fix everything though - we still have (genuine) issues with respect to casting the message buffer types - CFE_SB_Msg_t has larger alignment requirements than many of the messages themselves.

[CDKnightNASA]

Seeing similar with ES:

/home/pi/cFS/cfe/fsw/cfe-core/src/es/cfe_es_shell.c: In function ‘CFE_ES_ShellOutputCommand’:
/home/pi/cFS/cfe/fsw/cfe-core/src/es/cfe_es_shell.c:178:41: error: cast increases required alignment of target type [-Werror=cast-align]
                     CFE_SB_TimeStampMsg((CFE_SB_Msg_t *) &CFE_ES_TaskData.ShellPacket);
                                         ^
/home/pi/cFS/cfe/fsw/cfe-core/src/es/cfe_es_shell.c:179:36: error: cast increases required alignment of target type [-Werror=cast-align]
                     CFE_SB_SendMsg((CFE_SB_Msg_t *) &CFE_ES_TaskData.ShellPacket);
                                    ^
/home/pi/cFS/cfe/fsw/cfe-core/src/es/cfe_es_shell.c:208:37: error: cast increases required alignment of target type [-Werror=cast-align]
                 CFE_SB_TimeStampMsg((CFE_SB_Msg_t *) &CFE_ES_TaskData.ShellPacket);
                                     ^
/home/pi/cFS/cfe/fsw/cfe-core/src/es/cfe_es_shell.c:209:32: error: cast increases required alignment of target type [-Werror=cast-align]
                 CFE_SB_SendMsg((CFE_SB_Msg_t *) &CFE_ES_TaskData.ShellP

[CDKnightNASA]

similar with SB:

/home/pi/cFS/cfe/fsw/cfe-core/src/sb/cfe_sb_api.c: In function ‘CFE_SB_SubscribeFull’:
/home/pi/cFS/cfe/fsw/cfe-core/src/sb/cfe_sb_api.c:859:29: error: cast increases required alignment of target type [-Werror=cast-align]
       Stat = CFE_SB_SendMsg((CFE_SB_Msg_t *)&CFE_SB.SubRprtMsg);
                             ^

and TIME:

/home/pi/cFS/cfe/fsw/cfe-core/src/time/cfe_time_tone.c: In function ‘CFE_TIME_Tone1HzTask’:
/home/pi/cFS/cfe/fsw/cfe-core/src/time/cfe_time_tone.c:1220:28: error: cast increases required alignment of target type [-Werror=cast-align]
             CFE_SB_SendMsg((CFE_SB_Msg_t *) &CFE_TIME_TaskData.ToneSignalCmd);
                            ^
/home/pi/cFS/cfe/fsw/cfe-core/src/time/cfe_time_tone.c:1228:28: error: cast increases required alignment of target type [-Werror=cast-align]
             CFE_SB_SendMsg((CFE_SB_Msg_t *) &CFE_TIME_TaskData.ToneSendCmd);
                            ^
/home/pi/cFS/cfe/fsw/cfe-core/src/time/cfe_time_tone.c: In function ‘CFE_TIME_Local1HzTask’:
/home/pi/cFS/cfe/fsw/cfe-core/src/time/cfe_time_tone.c:1440:28: error: cast increases required alignment of target type [-Werror=cast-align]
             CFE_SB_SendMsg((CFE_SB_Msg_t *) &CFE_TIME_TaskData.Local1HzCmd);
                            ^

and in cmdUtil:

/home/pi/cFS/tools/cFS-GroundSystem/Subsystems/cmdUtil/SendUdp.c: In function ‘SendUdp’:
/home/pi/cFS/tools/cFS-GroundSystem/Subsystems/cmdUtil/SendUdp.c:90:20: error: cast increases required alignment of target type [-Werror=cast-align]
         inet_ntoa(((struct sockaddr_in*)result->ai_addr)->sin_addr), port);
                    ^

[skliper]

Targeting 7.0 to allow major tlm packet updates. Errors don't show up in 32bit build for MCP750 with CCSDS Version 2 set so not critical to 6.8.