- TF-A - lists.trustedfirmware.org

by Ash Wilding

Hi @François<mailto:francois.ozog@linaro.org>, <quote> Now, I changed U-Boot to Image, added code to ensure arg0 is 0 (DTB) but Linux does not start (zero printk visible). I don't find kernel text base anymore, may be it disappeared: any suggestion to get the kernel start when loaded at 64KB offset? the kernel image with embedded initrd is 10MB, SRAM is at 64MB so there should be enough space to decompress initrd... </quote> I recommend reading through the arm64 Linux booting requirements if you haven’t already; you’ll need to ensure all of those conditions are met before entering the kernel [1]. For example have you correctly set text_offset in the image header? <quote> u32 code0; /* Executable code */ u32 code1; /* Executable code */ u64 text_offset; /* Image load offset, little endian */ u64 image_size; /* Effective Image size, little endian */ u64 flags; /* kernel flags, little endian */ u64 res2 = 0; /* reserved */ u64 res3 = 0; /* reserved */ u64 res4 = 0; /* reserved */ u32 magic = 0x644d5241; /* Magic number, little endian, "ARM\x64" */ u32 res5; /* reserved (used for PE COFF offset) */ </quote> <quote> The Image must be placed text_offset bytes from a 2MB aligned base address anywhere in usable system RAM and called there. </quote> Kind regards, Ash. [1] https://elixir.bootlin.com/linux/latest/source/Documentation/arm64/booting.… 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.

5 years, 2 months

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Re: [TF-A] sp select in atf

by Ash Wilding

Hi Feng, This is standard practice for operating systems, hypervisors, and firmware running on Armv8-A systems. A key distinction between SPSel,#0 and SPSel,#1 is that you can tell which stack pointer you were using when you took an exception as they correspond to different offsets in the vector table. Often times, taking an exception from the same EL when using SPSel,#0 is non-terminal whereas taking an exception from the same EL when already using SPSel,#1 is considered terminal. Take for example the scenario where your operating system, hypervisor, or firmware is running some task/thread code at EL1/EL2/EL3 and runs out of stack space, triggering a translation fault and attempting to stack some data (we’ll probably be using unmapped guard pages at the stack boundaries). The first thing the exception handler will try to do is stack the GPRs. If the reason you took the exception is because the stack pointed to by SP_EL1/2/3 has itself overflowed, this attempt to stack the GPRs will itself cause a translation fault and you’ll get stuck in a recursive exception. In contrast, if the reason you took the exception is because the stack pointed to by SP_EL0 has overflowed, the exception handler will successfully stack the GPRs to the SP_EL1/2/3 stack and be able to diagnose + log what went wrong before rebooting gracefully. Hope that helps, Ash. From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> on behalf of Chen Feng via TF-A <tf-a(a)lists.trustedfirmware.org> Reply to: Chen Feng <puck.chen(a)hisilicon.com> Date: Friday, 17 April 2020 at 09:02 To: "tf-a(a)lists.trustedfirmware.org" <tf-a(a)lists.trustedfirmware.org>, Alexei Fedorov <Alexei.Fedorov(a)arm.com>, Yatharth Kochar <Yatharth.Kochar(a)arm.com>, Sandrine Bailleux <Sandrine.Bailleux(a)arm.com> Cc: "puck.chen(a)hisilicon.com" <puck.chen(a)hisilicon.com>, "lizhong11(a)hisilicon.com" <lizhong11(a)hisilicon.com> Subject: [TF-A] sp select in atf Hello all, I see the atf use different sp, and special for smc64 it use the sp_el0. So for the unhandled-exception handler, it must switch to sp_el0 to do the back-trace-dump. Since it default used sp_el3 when exception happen. My question here is why using different sp in atf code? Just use the sp_el3 for all scenes seems more simpler. Cheers, - feng -- TF-A mailing list TF-A(a)lists.trustedfirmware.org<mailto:TF-A@lists.trustedfirmware.org> https://lists.trustedfirmware.org/mailman/listinfo/tf-a 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.

5 years, 2 months

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sp select in atf

by Chen Feng

Hello all, I see the atf use different sp, and special for smc64 it use the sp_el0. So for the unhandled-exception handler, it must switch to sp_el0 to do the back-trace-dump. Since it default used sp_el3 when exception happen. My question here is why using different sp in atf code? Just use the sp_el3 for all scenes seems more simpler. Cheers, - feng

5 years, 2 months

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Re: [TF-A] Linux as BL33

by Manish Pandey2

As of now ARM_LINUX_KERNEL_AS_BL33 is only supported when RESET_TO_BL31=1, along with it you need to pass PRELOADED_BL33_BASE as well as ARM_PRELOADED_DTB_BASE. AFAIK This feature is not tested for platforms which uses all the BL(1/2/31) stages from TF-A . The most likely reason for this is loading and authentication of Linux Image. BL2 which is responsible for loading of various images, does not have support to load linux image. With platforms having RESET_TO_BL31, TF-A relies on prior loader which loads kernel and device tree blobs at respective address. In short, if your platform has RESET_TO_BL31=1, it will be quite easy else you need to understand the BL2 loading mechanism and see if you can extend it for loading Linux and DTB. Kernel Output format zImage/Image should work. Hope this helps! ________________________________ From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> on behalf of François Ozog via TF-A <tf-a(a)lists.trustedfirmware.org> Sent: 15 April 2020 13:31 To: tf-a(a)lists.trustedfirmware.org <tf-a(a)lists.trustedfirmware.org> Subject: [TF-A] Linux as BL33 I want to use Linux as BL33 on a Marvell Macchiatobin. Currently I have the successful boot flow: TFA (mainline v2.2) -> U-Boot (Mainline 2020.04rc5) -> Kernel (5.6.3) with U-root initrd (6.0.0, https://github.com/u-root/u-root ) -> Ubuntu 19.10 The 5.6.3 "intermediary" kernel is 5.5MB uncompressed , u-root initrd is 3.5MB compressed (some form of golang based busybox). I was pointed to the ARM_LINUX_KERNEL_AS_BL33 option which is not supported on the Macchiatobin. It does not look too difficult to add, but I'd like to have some feedback/guidance on how to do it: - how to add the option to the TFA platform - how to generate a usable kernel (compile options? non relocatable kernel? output format, i.e. Image, zImage, uImage...) Thanks for your help -FF -- TF-A mailing list TF-A(a)lists.trustedfirmware.org https://lists.trustedfirmware.org/mailman/listinfo/tf-a 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.

5 years, 2 months

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Re: [TF-A] Proposal for Measured Boot Implementation

by Vivek Prasad

+Harb ________________________________ From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> on behalf of Vivek Prasad via TF-A <tf-a(a)lists.trustedfirmware.org> Sent: Thursday, April 16, 2020 10:19 AM To: Stuart Yoder <stuart.yoder(a)arm.com>; Alexei Fedorov <Alexei.Fedorov(a)arm.com>; tf-a <tf-a(a)lists.trustedfirmware.org>; Raghu Krishnamurthy <raghu.ncstate(a)icloud.com> Cc: Loc Ho <loc.ho(a)amperecomputing.com>; Vivek Kumar <vivek(a)amperecomputing.com>; Benjamin Chaffin <bchaffin(a)amperecomputing.com>; Ard Biesheuvel <Ard.Biesheuvel(a)arm.com>; Mohamad Ammar <moe(a)amperecomputing.com>; Charles Garcia-Tobin <Charles.Garcia-Tobin(a)arm.com> Subject: Re: [TF-A] Proposal for Measured Boot Implementation Hello Stuart, Alexei, Chiming-in here on Ampere's behalf... We analysed this proposal internally. And we see a number issues with this, some of which was already raised by Raghu in the previous threads. Here is a summary of the main issues that we see. * Only supporting mbedtls, and this is fixed config at compile time. * We propose that there should be a variable for the algorithm to be used, which can be setup at initialization time. * This solution relies on taking the hash directly from the digest as the measurement, instead of the computed hash. This is not safe, especially considering measured boot may use a different hash bank, so digest hash may not be correct/valid. * Only measuring the BL2 image, per the ARM SBSG we must be measuring and logging *all* images/boot phases * BL31 * BL32 (all secure partitions) * BL33 (UEFI or any other non-secure boot loader) * Once we ERET into BL33, the measure boot flow continues and is owned by that boot loader * Only see support for PCR0, any/all unsigned config data must be logged to PCR1. * Passing PCRs to non-secure software before logging is not compliant with TCG Static-Root-of-Trust Measurement (SRTM) requirements * It was discussed before in separate conversations… especially in systems where you are talked about two different signing domains where BL33 is a different trust/signing domain. * BL33 should only do hash-log-extend… there is no need for BL33 to be aware of the current PCR value (beyond what is provided in the boot event log). * Based on comments on the mail thread, there seem to be bad assumptions/expectations around TPM accessibility from non-secure world. * Expecting SPI/I2C TPMs to be directly accessed from non-secure world instead of abstracting hardware details via the TCG CRB interface (which has been already standardized as the defacto mechanism for ARM on past mobile, client, and server solutions). * CRB will "just work" for Aptio/EDK2/Linux/Windows/Hyper-V/VMWare * NOTE: This goes back to what is a “productizable” TPM solution. We want it to be turn-key solution for customers without having to support/develop proprietary drivers. -Vivek/Harb

5 years, 2 months

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Re: [TF-A] Project Maintenance Proposal for tf.org Projects

by Sandrine Bailleux

Hi all, Thanks to all who have commented on this proposal so far. I've edited the original document to try and incorporate all feedback gathered so far (through the TSC meeting, this email thread and the TF-A tech call). Please have another look and flag anything I might have missed: https://developer.trustedfirmware.org/w/collaboration/project-maintenance-p… The major changes are: == Removed concept of self-review == This is proving too controversial, several people do not want to allow self-review. Roles of maintainer and code owner are still cumulative but cannot be both exercised for the same patch. The exact method of dealing with review bottleneck is still to be decided. In addition to the current proposal of increasing the maintainers pool, the most popular alternatives mentioned so far are: - Set a minimum wait time for feedback before a patch can be merged without any further delay. - Mandate distinct reviewers for a patch. == Enhanced the section "Patch contribution Guidelines" == Mentioned that patches should be small, on-topic, with comprehensive commit messages. == Added a note about how to deal with disagreement == If reviewers cannot find a common ground, the proposal is to call out a 3rd-party maintainer. == Removed "out-of-date" platform state == Squashed it into "limited support" to reduce the number of states. == Removed "orphan" state from platform support life cycle == This concept is orthogonal to the level of functionality. Added a note in the "Code Owner" section instead. == Per-project guidelines as a complementary document == Added a list of things that it would typically cover. == Added requirement on fully supported platforms to document the features they support == == Added todo mentioning that the proposal might cover branching strategies in the future == The full diff may be seen here: https://developer.trustedfirmware.org/phriction/diff/73/?l=4&r=5 This proposal is still open for discussion at this stage and further feedback is most welcome! Regards, Sandrine

5 years, 2 months

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Linux as BL33

by François Ozog

I want to use Linux as BL33 on a Marvell Macchiatobin. Currently I have the successful boot flow: TFA (mainline v2.2) -> U-Boot (Mainline 2020.04rc5) -> Kernel (5.6.3) with U-root initrd (6.0.0, https://github.com/u-root/u-root ) -> Ubuntu 19.10 The 5.6.3 "intermediary" kernel is 5.5MB uncompressed , u-root initrd is 3.5MB compressed (some form of golang based busybox). I was pointed to the ARM_LINUX_KERNEL_AS_BL33 option which is not supported on the Macchiatobin. It does not look too difficult to add, but I'd like to have some feedback/guidance on how to do it: - how to add the option to the TFA platform - how to generate a usable kernel (compile options? non relocatable kernel? output format, i.e. Image, zImage, uImage...) Thanks for your help -FF

5 years, 2 months

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Re: [TF-A] 回复：Re: [RAS] BL32 UnRecognized Event - 0xC4000061 and BL31 Crashed

by Matteo Carlini

Looping-in Thomas & Deepak, responsible for the RD-N1 landing team platforms releases. They might be able to help. Thanks Matteo From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> On Behalf Of ??(??) via TF-A Sent: 14 April 2020 06:47 To: TF-A <tf-a-bounces(a)lists.trustedfirmware.org>; Raghu Krishnamurthy via TF-A <tf-a(a)lists.trustedfirmware.org> Subject: [TF-A] 回复：Re: [RAS] BL32 UnRecognized Event - 0xC4000061 and BL31 Crashed Hi RagHu, Really appreciate your help. I was downloaded this software stack from git.linaro.org. This software stack include ATF, kernel, edk2 and so on. The user guide i used from linaro is:https://git.linaro.org/landing-teams/working/arm/arm-reference-platforms… 1) What platform you are running on? Can this issue be reproduced outside your testing environment, perhaps on FVP or QEMU? A: I am running on ARM N1-Edge FVP platform. It can reproduced on this FVP platform. 2) What version of TF-A and StandaloneMM is being used? Preferably the commit-id, so that we can be sure we are looking at the same code. A: TF-A: https://git.linaro.org/landing-teams/working/arm/arm-tf.git tag:RD-INFRA-20191024-RC0 StandloneMM seems build from edk2 & edk2-platform. so i just put edk2 and edk2-platform version information. if anything i missed, please let me know. edk2: https://git.linaro.org/landing-teams/working/arm/edk2.git<https://git.linaro.org/landing-teams/working/arm/edk2.git/> tag:RD-INFRA-20191024-RC0 edk2-platform: https://git.linaro.org/landing-teams/working/arm/edk2-platforms.git<https://git.linaro.org/landing-teams/working/arm/edk2-platforms.git/> tag:RD-INFRA-20191024-RC0 3) What version of the kernel and sdei driver is being used? A: kernel-release: https://git.linaro.org/landing-teams/working/arm/kernel-release.git tag:RD-INFRA-20191024-RC0 The sdei driver was included in kernel, do i need to provide sdei driver version? If need please let me know. 4) I can't tell from looking at the log but do you know if writing 0x123 to sde_ras_poison causes a DMC620 interrupt or an SError or external abort through memory access ? A: Sorry, linaro only refered it will inject the DMC-620 single-bit RAS error. So I am also not sure which exception type it will trigger. BRs， Bin Wu ------------------原始邮件 ------------------ 发件人:TF-A <tf-a-bounces(a)lists.trustedfirmware.org<mailto:tf-a-bounces@lists.trustedfirmware.org>> 发送时间:Tue Apr 14 01:25:47 2020 收件人:Raghu Krishnamurthy via TF-A <tf-a(a)lists.trustedfirmware.org<mailto:tf-a@lists.trustedfirmware.org>> 主题:Re: [TF-A] [RAS] BL32 UnRecognized Event - 0xC4000061 and BL31 Crashed Hello, >>Does BL31 need to send 0xC4000061 event to BL32 again? I don't think it will. It is really odd that 0xC4000061(SP_EVENT_COMPLETE_AARCH64) ever reaches the BL32/MM handler. This is from looking at the upstream code quickly but it definitely depends on the platform you are running, what version of TF-A you are using, build options used. Is it possible that the unhandled exception is occurring after successful handling of the DMC620 error but there is a following issue that occurs right after, causing the crash? From the register dump it looks like there was an Instruction abort exception at address 0 while running in EL3. Something seems to have gone seriously wrong to have 0xC4000061 ever go back to BL32 and to get an instruction abort at address 0. >>Does current TF-A support to run RAS test? It seems BL31 will crash. See above. The answer really depends on the factors mentioned above. The following would be helpful to know: 1) What platform you are running on? Can this issue be reproduced outside your testing environment, perhaps on FVP or QEMU? 2) What version of TF-A and StandaloneMM is being used? Preferably the commit-id, so that we can be sure we are looking at the same code. 3) What version of the kernel and sdei driver is being used? 4) I can't tell from looking at the log but do you know if writing 0x123 to sde_ras_poison causes a DMC620 interrupt or an SError or external abort through memory access ? Thanks Raghu On 4/13/20 12:16 AM, 吴斌(郅隆) via TF-A wrote: > Dear Friends, > > I am using TF-A to test RAS feature. > When I triggered DMC620 RAS error in Linux(echo 0x123 > > /sys/kernel/debug/sdei_ras_poison). > BL32 will recieve > UnRecognized Event - 0xC4000061(SP_EVENT_COMPLETE_AARCH64) and finally > BL31 crashed. > > In my understanding, this 0xC4000061 should consumed by BL31, not send > it to BL32 again. > > A piece of error log as below: > > ************************************* > > CperWrite - CperAddress@0xFF610064 > CperWrite - 1 Section@FFBE91A8, Length 80, SectionType@FFBE9138 > CperWrite - Got Error Section: Platform Memory. > MmEntryPoint Done > Received delegated event > X0 : 0xC4000061 > X1 : 0x0 > X2 : 0x0 > X3 : 0x0 > Received event - 0xC4000061 on cpu 0 > UnRecognized Event - 0xC4000061 > Failed delegated event 0xC4000061, Status 0x2 > Unhandled Exception in EL3. > x30 = 0x0000000000000000 > x0 = 0x00000000ff007e00 > x1 = 0xfffffffffffffffe > x2 = 0x00000000600003c0 > x3 = 0x0000000000000000 > x4 = 0x0000000000000000 > x5 = 0x0000000000000000 > x6 = 0x00000000ff015080 > x7 = 0x0000000000000000 > x8 = 0x00000000c4000061 > x9 = 0x0000000000000021 > x10 = 0x0000000000000040 > x11 = 0x00000000ff00f2b0 > x12 = 0x00000000ff0118c0 > x13 = 0x0000000000000002 > x14 = 0x00000000ff016b70 > x15 = 0x00000000ff003f20 > x16 = 0x0000000000000044 > x17 = 0x00000000ff010430 > x18 = 0x0000000000000e3c > x19 = 0x0000000000000000 > More error log please refer to attachment. > > My question is, > 1. Does BL31 need to send 0xC4000061 event to BL32 again? > 2. Does current TF-A support to run RAS test? It seems BL31 will crash. > > Appreciate your help. > > BRs， > Bin Wu > -- TF-A mailing list TF-A(a)lists.trustedfirmware.org<mailto:TF-A@lists.trustedfirmware.org> https://lists.trustedfirmware.org/mailman/listinfo/tf-a

5 years, 2 months

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回复：Re: [RAS] BL32 UnRecognized Event - 0xC4000061 and BL31 Crashed

by 吴斌(郅隆)

Hi RagHu, Really appreciate your help. I was downloaded this software stack from git.linaro.org. This software stack include ATF, kernel, edk2 and so on. The user guide i used from linaro is:https://git.linaro.org/landing-teams/working/arm/arm-reference-platforms… 1) What platform you are running on? Can this issue be reproduced outside your testing environment, perhaps on FVP or QEMU? A: I am running on ARM N1-Edge FVP platform. It can reproduced on this FVP platform. 2) What version of TF-A and StandaloneMM is being used? Preferably the commit-id, so that we can be sure we are looking at the same code. A: TF-A: https://git.linaro.org/landing-teams/working/arm/arm-tf.git tag:RD-INFRA-20191024-RC0 StandloneMM seems build from edk2 & edk2-platform. so i just put edk2 and edk2-platform version information. if anything i missed, please let me know. edk2: https://git.linaro.org/landing-teams/working/arm/edk2.git tag:RD-INFRA-20191024-RC0 edk2-platform: https://git.linaro.org/landing-teams/working/arm/edk2-platforms.git tag:RD-INFRA-20191024-RC0 3) What version of the kernel and sdei driver is being used? A: kernel-release: https://git.linaro.org/landing-teams/working/arm/kernel-release.git tag:RD-INFRA-20191024-RC0 The sdei driver was included in kernel, do i need to provide sdei driver version? If need please let me know. 4) I can't tell from looking at the log but do you know if writing 0x123 to sde_ras_poison causes a DMC620 interrupt or an SError or external abort through memory access ? A: Sorry, linaro only refered it will inject the DMC-620 single-bit RAS error. So I am also not sure which exception type it will trigger. BRs， Bin Wu ------------------原始邮件 ------------------ 发件人:TF-A <tf-a-bounces(a)lists.trustedfirmware.org> 发送时间:Tue Apr 14 01:25:47 2020 收件人:Raghu Krishnamurthy via TF-A <tf-a(a)lists.trustedfirmware.org> 主题:Re: [TF-A] [RAS] BL32 UnRecognized Event - 0xC4000061 and BL31 Crashed Hello, >>Does BL31 need to send 0xC4000061 event to BL32 again? I don't think it will. It is really odd that 0xC4000061(SP_EVENT_COMPLETE_AARCH64) ever reaches the BL32/MM handler. This is from looking at the upstream code quickly but it definitely depends on the platform you are running, what version of TF-A you are using, build options used. Is it possible that the unhandled exception is occurring after successful handling of the DMC620 error but there is a following issue that occurs right after, causing the crash? From the register dump it looks like there was an Instruction abort exception at address 0 while running in EL3. Something seems to have gone seriously wrong to have 0xC4000061 ever go back to BL32 and to get an instruction abort at address 0. >>Does current TF-A support to run RAS test? It seems BL31 will crash. See above. The answer really depends on the factors mentioned above. The following would be helpful to know: 1) What platform you are running on? Can this issue be reproduced outside your testing environment, perhaps on FVP or QEMU? 2) What version of TF-A and StandaloneMM is being used? Preferably the commit-id, so that we can be sure we are looking at the same code. 3) What version of the kernel and sdei driver is being used? 4) I can't tell from looking at the log but do you know if writing 0x123 to sde_ras_poison causes a DMC620 interrupt or an SError or external abort through memory access ? Thanks Raghu On 4/13/20 12:16 AM, 吴斌(郅隆) via TF-A wrote: > Dear Friends, > > I am using TF-A to test RAS feature. > When I triggered DMC620 RAS error in Linux(echo 0x123 > > /sys/kernel/debug/sdei_ras_poison). > BL32 will recieve > UnRecognized Event - 0xC4000061(SP_EVENT_COMPLETE_AARCH64) and finally > BL31 crashed. > > In my understanding, this 0xC4000061 should consumed by BL31, not send > it to BL32 again. > > A piece of error log as below: > > ************************************* > > CperWrite - CperAddress@0xFF610064 > CperWrite - 1 Section@FFBE91A8, Length 80, SectionType@FFBE9138 > CperWrite - Got Error Section: Platform Memory. > MmEntryPoint Done > Received delegated event > X0 : 0xC4000061 > X1 : 0x0 > X2 : 0x0 > X3 : 0x0 > Received event - 0xC4000061 on cpu 0 > UnRecognized Event - 0xC4000061 > Failed delegated event 0xC4000061, Status 0x2 > Unhandled Exception in EL3. > x30 = 0x0000000000000000 > x0 = 0x00000000ff007e00 > x1 = 0xfffffffffffffffe > x2 = 0x00000000600003c0 > x3 = 0x0000000000000000 > x4 = 0x0000000000000000 > x5 = 0x0000000000000000 > x6 = 0x00000000ff015080 > x7 = 0x0000000000000000 > x8 = 0x00000000c4000061 > x9 = 0x0000000000000021 > x10 = 0x0000000000000040 > x11 = 0x00000000ff00f2b0 > x12 = 0x00000000ff0118c0 > x13 = 0x0000000000000002 > x14 = 0x00000000ff016b70 > x15 = 0x00000000ff003f20 > x16 = 0x0000000000000044 > x17 = 0x00000000ff010430 > x18 = 0x0000000000000e3c > x19 = 0x0000000000000000 > More error log please refer to attachment. > > My question is, > 1. Does BL31 need to send 0xC4000061 event to BL32 again? > 2. Does current TF-A support to run RAS test? It seems BL31 will crash. > > Appreciate your help. > > BRs， > Bin Wu > -- TF-A mailing list TF-A(a)lists.trustedfirmware.org https://lists.trustedfirmware.org/mailman/listinfo/tf-a

5 years, 2 months

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Re: [TF-A] BRANCH_PROTECTION

by Alexei Fedorov

Hi Varun, 1. The value of '1' sets ‘standard’ type of BP which according to GCC documentation: "turns on all types of branch protection features. If a feature has additional tuning options, then ‘standard’ sets it to its standard level. " It equals to "bti+pac-ret". 2. Yes. See above and use option value of '1'. Regards. Alexei ________________________________ From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> on behalf of Varun Wadekar via TF-A <tf-a(a)lists.trustedfirmware.org> Sent: 10 April 2020 19:28 To: tf-a(a)lists.trustedfirmware.org <tf-a(a)lists.trustedfirmware.org> Cc: Kalyani Chidambaram Vaidyanathan <kalyanic(a)nvidia.com>; Anthony Zhou <anzhou(a)nvidia.com> Subject: Re: [TF-A] BRANCH_PROTECTION Hello, Can someone please help clarify? -Varun From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> On Behalf Of Varun Wadekar via TF-A Sent: Tuesday, April 7, 2020 9:58 PM To: tf-a(a)lists.trustedfirmware.org Cc: Kalyani Chidambaram Vaidyanathan <kalyanic(a)nvidia.com>; Anthony Zhou <anzhou(a)nvidia.com> Subject: [TF-A] BRANCH_PROTECTION External email: Use caution opening links or attachments Hello, Can someone please help me understand if 1. a ‘value’ of ‘1’ for BRANCH_PROTECTION covers the PAuth protection provided by a value of ‘2’ and/or ‘3’? 2. there is a way to enable BTI and “pac-ret” at the same time? The docs provide this information. <snip> - ``BRANCH_PROTECTION``: Numeric value to enable ARMv8.3 Pointer Authentication and ARMv8.5 Branch Target Identification support for TF-A BL images themselves. If enabled, it is needed to use a compiler that supports the option ``-mbranch-protection``. Selects the branch protection features to use: - 0: Default value turns off all types of branch protection - 1: Enables all types of branch protection features - 2: Return address signing to its standard level - 3: Extend the signing to include leaf functions The table below summarizes ``BRANCH_PROTECTION`` values, GCC compilation options and resulting PAuth/BTI<https://tegra-sw-opengrok.nvidia.com/source/s?path=PAuth/BTI&project=stage-…> features. +-------+--------------+-------+-----+ | Value | GCC option | PAuth | BTI | +=======+==============+=======+=====+ | 0 | none | N | N | +-------+--------------+-------+-----+ | 1 | standard | Y | Y | +-------+--------------+-------+-----+ | 2 | pac-ret | Y | N | +-------+--------------+-------+-----+ | 3 | pac-ret+leaf | Y | N | +-------+--------------+-------+-----+ This option defaults to 0 and this is an experimental feature. Note that Pointer Authentication is enabled for Non-secure world irrespective of the value of this option if the CPU supports it. <snip> Thanks, Varun ________________________________ This email message is for the sole use of the intended recipient(s) and may contain confidential information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. ________________________________ 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.

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