February 2020 - TF-M - lists.trustedfirmware.org

Possible race condition in IRQ_TEST_SCENARIO_4?

by Thomas Törnblom

How is the IRQ_TEST_SCENARIO_4 supposed to work? I suspect that there might be a lurking race condition somewhere in that test. Some, not all, of the (M33/M23) targets gets stuck in that test when the ConfigRegression.cmake config is built with IAR in Debug mode. If I build it with RelWithDebInfo then the test runs OK for all applicable targets. No problems with Debug builds for the other configurations. Occasionally the test will run successfully also for a normally problematic target if I run it in the debugger and stop execution at breakpoints, but it is very random, which is why I suspect there might be a race problem. Thomas -- *Thomas Törnblom*, /Product Engineer/ IAR Systems AB Box 23051, Strandbodgatan 1 SE-750 23 Uppsala, SWEDEN Mobile: +46 76 180 17 80 Fax: +46 18 16 78 01 E-mail: thomas.tornblom(a)iar.com <mailto:thomas.tornblom@iar.com> Website: www.iar.com <http://www.iar.com> Twitter: www.twitter.com/iarsystems <http://www.twitter.com/iarsystems>

4 years, 10 months

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Re: [TF-M] Changes to OS wrapper

by Jamie Fox

Hi Vikas, I still do not really understand the rationale for these changes. If dynamic memory allocation inside the os_wrapper shim is really what you want to do, then what is stopping you from implementing the following? os_wrapper_thread_new() { malloc(external_to_os_resource) /* create thread */ } os_wrapper_thread_delete() { free(external_to_os_resource) } Kind regards, Jamie From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org> On Behalf Of Vikas Katariya via TF-M Sent: 05 February 2020 10:20 To: tf-m(a)lists.trustedfirmware.org Subject: Re: [TF-M] Changes to OS wrapper Hi all, The patch set has been updated with further changes: * https://review.trustedfirmware.org/c/trusted-firmware-m/+/3294 OS wrapper layers help to create Mutex, Semaphores, and Thread on an OS. The wrapper was designed to be implemented on platforms that dynamically allocate memory or objects from a predefined OS memory pool. The current shape of the OS wrapper is not a good fit for work with operating systems that require manual memory management. For example, if the child thread created in ns_test_helpers.c does a simple os_wrapper_thread_exit(), this does not give any opportunity for manually-managed thread resources to be freed; this leads to a memory leak. Therefore os_wrapper_current_thread_suspend() and os_wrapper_thread_delete() are introduced to aid scenarios where manual memory management is required. The removal of os_wrapper_thread_exit() is warranted as it encourages applications to avoid memory leak scenarios by requiring applications to remember to call os_wrapper_thread_terminate(). If we were to keep os_wrapper_thread_exit() around, this would impose undue cognitive overhead on wrapper users by making os_wrapper_thread_exit() do something other than exit the current thread (on platforms requiring manual memory management); an os_wrapper_thread_exit() implementation could not actually exit a thread on a manual memory managed OS, as the thread must remain valid until clean up time, and exiting the thread would invalidate the OS's thread resource. * https://review.trustedfirmware.org/c/trusted-firmware-m/+/3299 These changes reflect to avoid memory leaks on operating systems that use manually managed dynamic memory allocation but not from static memory/objects pools, allowing them to free after usage. Remove "get_handle" because it's not possible to implement it efficiently on systems that require manual memory management. The os-wrapper handle must be different from the actual underlying OS handle on a manually-memory-managed system in order to allow the resources be freed which are not managed by the OS. For example: struct { os_handle; external_to_os_resource; }; The os-wrapper knows more about the resources being managed than the OS itself. It is supposed to return an OS Wrapper handle than OS handle, because implementations can't always create an os-wrapper handle from an OS handle. In this case the os-wrapper handle could be a pointer to this struct, but could not be just the os_handle directly. Further os_wrapper_current_thread_get_priority() is used to avoid confusion between the top and bottom layer handles, because the older implementation can refer to different object types when operating across multiple layers. * https://review.trustedfirmware.org/c/trusted-firmware-m/+/3347 - Improves test efficiency. Please review and share your thoughts. Thanks & Best Regards, Vikas Katariya From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org<mailto:tf-m-bounces@lists.trustedfirmware.org>> On Behalf Of Vikas Katariya via TF-M Sent: Monday, January 27, 2020 15:52 To: tf-m(a)lists.trustedfirmware.org<mailto:tf-m@lists.trustedfirmware.org> Subject: [TF-M] App: Changes to OS wrapper Hi all, I am proposing new changes to OS wrapper layer to help other RTOS use dynamic memory allocation. OS wrapper layers help to create Mutex, Semaphores, and Thread on RTOS. The wrapper is designed to use static allocation of memory/objects from predefined OS memory pool, which is not fully featured enough to allow dynamic memory allocation and freeing them after completion, if an RTOS requires that kind of implementation. For example, the child thread created in ns_test_helpers.c does a simple exit without passing a handle if the memory was dynamically allocated, which is a memory leak scenario. Therefore os_wrapper_thread_suspend() and os_wrapper_thread_delete() are introduced to aid scenarios where dynamic memory allocation and freeing is required. In the current patch we just suspend the child thread and terminate it from parent thread. The patch is open for review here: https://review.trustedfirmware.org/c/trusted-firmware-m/+/3294 Thanks & Best Regards, Vikas Katariya IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.

4 years, 10 months

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Re: [TF-M] Stuck in tfm_nspm_thread_entry() after "Initialize IPC SPM in handler mode"

by Ken Liu

I have created the patch for this issue: https://review.trustedfirmware.org/c/trusted-firmware-m/+/3359 The non-secure entry thread re-uses the same context and stack of initial booting thread, while initial booting thread would update the context in stack while SVC to SPM initialization. The context needs to be reset after SPM initialized all threads, and the EXC_RETURN is missed during the reset process. If initial thread is executed with FP active, the EXC_RETURN generated by SVC would be 0xFFFFFFED, and cause extra 0x48 bytes to be popped while exiting from exception which causes the error. This patch resets the EXC_RETURN to 0xFFFFFFFD. Please help to comment, thanks. /Ken ________________________________ From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org> on behalf of Ken Liu via TF-M <tf-m(a)lists.trustedfirmware.org> Sent: Wednesday, January 22, 2020 10:29 AM To: tf-m(a)lists.trustedfirmware.org <tf-m(a)lists.trustedfirmware.org> Cc: nd <nd(a)arm.com> Subject: Re: [TF-M] Stuck in tfm_nspm_thread_entry() after "Initialize IPC SPM in handler mode" Hi Andrej, I double checked in my platforms and looks fine, so you are porting them to your board, right? I have created a task for detailed description, let’s discuss the details there: https://developer.trustedfirmware.org/T652 Thanks. /Ken From: Andrej Butok <andrey.butok(a)nxp.com> Sent: Tuesday, January 21, 2020 11:19 PM To: Ken Liu <Ken.Liu(a)arm.com> Cc: tf-m(a)lists.trustedfirmware.org Subject: RE: Stuck in tfm_nspm_thread_entry() after "Initialize IPC SPM in handler mode" Hi Ken, Yes, we are using L2. I have just switched to the latest commit which includes the suggested fix. But tfm_nspm_thread_entry() still goes to the MemManage_Handler() fault a bit later on "push {r0, r1} \n" Thanks, Andrej From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org<mailto:tf-m-bounces@lists.trustedfirmware.org>> On Behalf Of Ken Liu via TF-M Sent: Tuesday, January 21, 2020 6:05 AM To: tf-m(a)lists.trustedfirmware.org<mailto:tf-m@lists.trustedfirmware.org> Cc: nd <nd(a)arm.com<mailto:nd@arm.com>> Subject: Re: [TF-M] Stuck in tfm_nspm_thread_entry() after "Initialize IPC SPM in handler mode" Hi Andrej, I guess you are using the level2 configuration. This fault was caused by tfm_nspm_thread_entry is trying to call a function in the privileged area. This commit ‘cba90782908626f955fe361f803558181a85c6fc’ fixes this problem. /Ken From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org<mailto:tf-m-bounces@lists.trustedfirmware.org>> On Behalf Of Andrej Butok via TF-M Sent: Tuesday, January 21, 2020 12:14 AM To: tf-m(a)lists.trustedfirmware.org<mailto:tf-m@lists.trustedfirmware.org> Subject: [TF-M] Stuck in tfm_nspm_thread_entry() after "Initialize IPC SPM in handler mode" Hello, Just want to check if this is a known issue. During synchronization to the latest TFM, TFM applications are stuck in the exception handler tfm_nspm_thread_entry ()=>MemManage_Handler(). This issue has been caused by commits (3.1.2020): 1. Revision: 5248af2d7b86775364a0e131eb80ac0330bc81fb Message: Core: Use naked function for ns jumping 1. Revision: 490281df3736b11b62e25bc98d3e2c6e4e10478c Message: Core: Initialize IPC SPM in handler mode The previous commit is fully OK (committed 2.1.2020): Revision: 93dabfd3a35faf9ed88285e09997491e93cefa5c Message: Core: Trigger a system reset for programmer error The commits do not have any changes in the linker files and no changes in target files, only the common and ARMv8 code. It’s good to know if this is something known or met before. Thank you, Andrej

4 years, 10 months

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Re: [TF-M] Topic proposal for upcoming Open Tech Forum: CMSIS-Zone

by Anton Komlev

Hi Jonatan, All, Thanks for proposing the topic inline with the thread on flash_layout.h and region_defs.h configuration header. Let's discuss it tomorrow. All the best, Anton Komlev From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org> On Behalf Of Jonatan Antoni via TF-M Sent: 05 February 2020 14:11 To: tf-m(a)lists.trustedfirmware.org Subject: [TF-M] Topic proposal for upcoming Open Tech Forum: CMSIS-Zone Hi all, I'd like to propose to give you a short live presentation (10-15 minutes) of CMSIS-Zone [1]. In Arm DSG we are developing and using CMSIS-Zone to gather required memory partitioning data and generate consistent config file (such as partition headers, SAU/MPC/PPC configs, MPU configs, scatter files, etc). Robi made good progress aligning TF-M with Arm's tool ecosystem, such as componentization for shipping CMSIS-Packs. He used CMSIS-Zone to generate the required config files for TF-M. In my presentation I'd like to focus on configuring TF-M for NXP's LPC55 using CMSIS-Zone. Cheers, Jonatan Antoni Senior Engineering Manager - CMSIS [Germany on Google Android 8.0] [United Kingdom on Google Android 8.0] [1] https://arm-software.github.io/CMSIS_5/Zone/html/index.html Arm Germany GmbH Phone: +49 (0)89 262 029 618 | Fax: +49 (0)89 456 040-19 Email: jonatan.antoni(a)arm.com<mailto:jonatan.antoni@arm.com> | Visit: www.keil.com<http://www.keil.com > | Address: Bretonischer Ring 16, 85630 Grasbrunn, Germany Sitz der Gesellschaft: Grasbrunn | Handelsregister: München (HRB 175362) | USt-IdNr.: DE 187925309 Geschäftsführer: Joachim Krech, Reinhard Keil IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.

4 years, 10 months

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Topic proposal for upcoming Open Tech Forum: CMSIS-Zone

by Jonatan Antoni

Hi all, I'd like to propose to give you a short live presentation (10-15 minutes) of CMSIS-Zone [1]. In Arm DSG we are developing and using CMSIS-Zone to gather required memory partitioning data and generate consistent config file (such as partition headers, SAU/MPC/PPC configs, MPU configs, scatter files, etc). Robi made good progress aligning TF-M with Arm's tool ecosystem, such as componentization for shipping CMSIS-Packs. He used CMSIS-Zone to generate the required config files for TF-M. In my presentation I'd like to focus on configuring TF-M for NXP's LPC55 using CMSIS-Zone. Cheers, Jonatan Antoni Senior Engineering Manager - CMSIS [Germany on Google Android 8.0] [United Kingdom on Google Android 8.0] [1] https://arm-software.github.io/CMSIS_5/Zone/html/index.html Arm Germany GmbH Phone: +49 (0)89 262 029 618 | Fax: +49 (0)89 456 040-19 Email: jonatan.antoni(a)arm.com<mailto:jonatan.antoni@arm.com> | Visit: www.keil.com<http://www.keil.com > | Address: Bretonischer Ring 16, 85630 Grasbrunn, Germany Sitz der Gesellschaft: Grasbrunn | Handelsregister: München (HRB 175362) | USt-IdNr.: DE 187925309 Geschäftsführer: Joachim Krech, Reinhard Keil IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.

4 years, 10 months

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Re: [TF-M] PSA Test Suite - Attestation test

by Tamas Ban

Hi Andrej, Could you tell what was the values of these compile time switches in your test? I assume you did the test on NXP board. Further do you implemented the boot data sharing between bootloader and runtime firmware? Do you sign SPE and NPSE images together or they are signed separately? Tamas From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org> On Behalf Of Andrej Butok via TF-M Sent: 04 February 2020 17:33 To: tf-m(a)lists.trustedfirmware.org Subject: [TF-M] PSA Test Suite - Attestation test Hello, After upgrade to the latest version of TFM, the Attestation test from the PSA Test Suite is failed (but the TFM Attestation regression tests are passed). What combination of configuration parameters must be used (INCLUDE_OPTIONAL_CLAIMS, INCLUDE_TEST_CODE, INCLUDE_COSE_KEY_ID, BOOT_DATA_AVAILABLE) to follow PSA Test Suite expectations? What commit of the PSA Test-suite must be used for the latest TFM? We are still on the 2019-07-25 (c80681ed7c7f3e2cbf02ded1ef2464ba2ca7ccd5) commit, which was OK with 2-month old TFM. Is the PSA Test Suite Attestation test valid for the latest TFM? Thank you, Andrej Butok IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.

4 years, 10 months

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Invitation: TF-M Tech Forum @ Thu 6 Feb 2020 17:00 - 18:00 (GMT) (tf-m@lists.trustedfirmware.org)

by Bill Fletcher

You have been invited to the following event. Title: TF-M Tech Forum This is an open forum for anyone to participate and it is not restricted to Trusted Firmware project members. It will operate under the guidance of the TF TSC.Feel free to forward it to colleagues.Details of previous meetings are here: https://www.trustedfirmware.org/meetings/tf-m-technical-forum/──… Fletcher is inviting you to a scheduled Zoom meeting.Join Zoom Meetinghttps://zoom.us/j/5810428000Meeting ID: 581 042 8000One tap mobile+16465588656,,5810428000# US (New York)+16699009128,,5810428000# US (San Jose)Dial by your location +1 646 558 8656 US (New York) +1 669 900 9128 US (San Jose) 877 853 5247 US Toll-free 888 788 0099 US Toll-freeMeeting ID: 581 042 8000Find your local number: https://zoom.us/u/aerUYXPhSL────────── When: Thu 6 Feb 2020 17:00 – 18:00 United Kingdom Time Where: https://zoom.us/j/5810428000 Calendar: tf-m(a)lists.trustedfirmware.org Who: * Bill Fletcher- organiser * tf-m(a)lists.trustedfirmware.org Event details: https://www.google.com/calendar/event?action=VIEW&eid=MGxvN2syYWc0ZWV1NXFia… Invitation from Google Calendar: https://www.google.com/calendar/ You are receiving this courtesy email at the account tf-m(a)lists.trustedfirmware.org because you are an attendee of this event. To stop receiving future updates for this event, decline this event. Alternatively, you can sign up for a Google Account at https://www.google.com/calendar/ and control your notification settings for your entire calendar. Forwarding this invitation could allow any recipient to send a response to the organiser and be added to the guest list, invite others regardless of their own invitation status or to modify your RSVP. Learn more at https://support.google.com/calendar/answer/37135#forwarding

4 years, 10 months

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Re: [TF-M] Changes to OS wrapper

by Vikas Katariya

Hi all, The patch set has been updated with further changes: * https://review.trustedfirmware.org/c/trusted-firmware-m/+/3294 OS wrapper layers help to create Mutex, Semaphores, and Thread on an OS. The wrapper was designed to be implemented on platforms that dynamically allocate memory or objects from a predefined OS memory pool. The current shape of the OS wrapper is not a good fit for work with operating systems that require manual memory management. For example, if the child thread created in ns_test_helpers.c does a simple os_wrapper_thread_exit(), this does not give any opportunity for manually-managed thread resources to be freed; this leads to a memory leak. Therefore os_wrapper_current_thread_suspend() and os_wrapper_thread_delete() are introduced to aid scenarios where manual memory management is required. The removal of os_wrapper_thread_exit() is warranted as it encourages applications to avoid memory leak scenarios by requiring applications to remember to call os_wrapper_thread_terminate(). If we were to keep os_wrapper_thread_exit() around, this would impose undue cognitive overhead on wrapper users by making os_wrapper_thread_exit() do something other than exit the current thread (on platforms requiring manual memory management); an os_wrapper_thread_exit() implementation could not actually exit a thread on a manual memory managed OS, as the thread must remain valid until clean up time, and exiting the thread would invalidate the OS's thread resource. * https://review.trustedfirmware.org/c/trusted-firmware-m/+/3299 These changes reflect to avoid memory leaks on operating systems that use manually managed dynamic memory allocation but not from static memory/objects pools, allowing them to free after usage. Remove "get_handle" because it's not possible to implement it efficiently on systems that require manual memory management. The os-wrapper handle must be different from the actual underlying OS handle on a manually-memory-managed system in order to allow the resources be freed which are not managed by the OS. For example: struct { os_handle; external_to_os_resource; }; The os-wrapper knows more about the resources being managed than the OS itself. It is supposed to return an OS Wrapper handle than OS handle, because implementations can't always create an os-wrapper handle from an OS handle. In this case the os-wrapper handle could be a pointer to this struct, but could not be just the os_handle directly. Further os_wrapper_current_thread_get_priority() is used to avoid confusion between the top and bottom layer handles, because the older implementation can refer to different object types when operating across multiple layers. * https://review.trustedfirmware.org/c/trusted-firmware-m/+/3347 - Improves test efficiency. Please review and share your thoughts. Thanks & Best Regards, Vikas Katariya From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org> On Behalf Of Vikas Katariya via TF-M Sent: Monday, January 27, 2020 15:52 To: tf-m(a)lists.trustedfirmware.org Subject: [TF-M] App: Changes to OS wrapper Hi all, I am proposing new changes to OS wrapper layer to help other RTOS use dynamic memory allocation. OS wrapper layers help to create Mutex, Semaphores, and Thread on RTOS. The wrapper is designed to use static allocation of memory/objects from predefined OS memory pool, which is not fully featured enough to allow dynamic memory allocation and freeing them after completion, if an RTOS requires that kind of implementation. For example, the child thread created in ns_test_helpers.c does a simple exit without passing a handle if the memory was dynamically allocated, which is a memory leak scenario. Therefore os_wrapper_thread_suspend() and os_wrapper_thread_delete() are introduced to aid scenarios where dynamic memory allocation and freeing is required. In the current patch we just suspend the child thread and terminate it from parent thread. The patch is open for review here: https://review.trustedfirmware.org/c/trusted-firmware-m/+/3294 Thanks & Best Regards, Vikas Katariya IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.

4 years, 10 months

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MPS3/AN524 assistance requested

by Thomas Törnblom

To finish off the IAR port of TF-M I've added the MPS2 and MPS3 targets. The MPS2 targets works fine, but I need some assistance with getting the MPS3/AN524 port to run. I've followed the tfm_user_guide.rst, but I can't get it running with ARMCLANG or gcc either, so I suspect there is something I've missed. The board runs the an524 selftest successfully, and it shows an image on the display as well as produces output on one of the USB serial ports when I configure the board for this. I added the REMAP options described in the user guide to /MB/HBI<BoardNumberBoardrevision>/AN524/an524_v2.txt (the doc mentions v1) I updated the image.txt file with the suggested lines, except for the IMAGE0UPDATE/IMAGE1UPDATE: AUTO lines, which caused a boot error. I tried AUTOQSPI, but settled on NONE. The LOG.TXT file shows no errors What am I missing? Thomas -- *Thomas Törnblom*, /Product Engineer/ IAR Systems AB Box 23051, Strandbodgatan 1 SE-750 23 Uppsala, SWEDEN Mobile: +46 76 180 17 80 Fax: +46 18 16 78 01 E-mail: thomas.tornblom(a)iar.com <mailto:thomas.tornblom@iar.com> Website: www.iar.com <http://www.iar.com> Twitter: www.twitter.com/iarsystems <http://www.twitter.com/iarsystems>

4 years, 10 months

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Re: [TF-M] TF-M NS regression tests - linker issue

by Devaraj Ranganna

Hi Ken, Currently, TF-M build process creates an pre-compiled archive of NS tests and exports it. But the implementation of `tfm_log_printf` is not exported. This causes a linker issue when NS tests archive is linked with NS RTOS, which is the reason why subject of this mail contains `linker issue`. Having said that, exporting `tfm_log_printf` won’t solve the problem because `tfm_log_printf` assumes availability of CMSIS driver framework. Also the latest suggestion on the ticket https://developer.trustedfirmware.org/T664 `And I think if you forward the TEST_LOG to your OS printf implementation then everything would be fine?` won’t help because of pre-compiled archive. It looks like only possible solution for NS RTOS is to implement ` tfm_log_printf `. Please do recommend if you have any other ideas. Thanks, Dev From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org> on behalf of Ken Liu via TF-M <tf-m(a)lists.trustedfirmware.org> Reply to: Ken Liu <Ken.Liu(a)arm.com> Date: Saturday, 1 February 2020 at 04:46 To: "tf-m(a)lists.trustedfirmware.org" <tf-m(a)lists.trustedfirmware.org> Cc: nd <nd(a)arm.com> Subject: Re: [TF-M] TF-M NS regression tests - linker issue Hi, Why the title is ‘linker issue’ since it is discussing about the printf things? /Ken From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org> On Behalf Of Devaraj Ranganna via TF-M Sent: Friday, January 31, 2020 9:57 PM To: TF-M(a)lists.trustedfirmware.org Subject: [TF-M] TF-M NS regression tests - linker issue Hi, The TF-M NS regression tests were portable enough to run in a rich OS environment. After replacing printf with tfm_log_printf, the TF-M regression tests are now no longer portable enough to run in an OS environment. Many OSes already have a way to print, usually via a printf function, and the TF-M regression tests probably should use this. It's important that TF-M regression tests remain portable and capable of running in an OS environment so that system integrators can be confident that TF-M is working as intended post-integration. I’ve already created a ticket for this https://developer.trustedfirmware.org/T664 Response from Ken in the ticket: Hi Jamie, The background for this changing is, the ARMCLANG printf involves \_\_stdout' into the image and this conflicts with some CMSIS functionalities. (CMSIS team reported that __stdout would affect the mutex init in ARMCLANG). That is the reason why I skipped the default printf. I think for an RTOS, the toolchain provided printf sometimes come with unknown symbols and causes unexpected behaviour, as the discussion in list/channel, most people are trying to avoid toolchain printf and use some lightweight output. And for the test, it should use wrapped TEST_LOG(), instead of calling printf itself, since some RTOS do not provide a std 'printf' function. Is there any discussion thread about this issue? Thanks Thanks, Dev IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.

4 years, 10 months

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