On 2/22/21 11:26 AM, Jerome Forissier via OP-TEE wrote:
> Hi Robert,
>
> On 2/22/21 11:01 AM, Robert Delien via OP-TEE wrote:
>> Hi,
>>
>> In imx_csu.c, the Central Security Unit's CSU_CSL*n* registers are set,
>> configuring access privileges for different peripherals. These registers
>> range from CSU_CSL0 (@ 0x021c0000) to CSU_CSL39 (@ 0x021c009c).
>>
>> The different i.MX6 platform variants each have their individual tables,
>> filled with sets of CSL index and register value, terminated by a sentinel
>> set with the index set to -1. (the reason for the parentheses around -1
>> espaces me)
>>
>> in .../core/arch/arm/plat-imx/drivers/imx_csu.c:csu_init()@115, a while
>> loop runs through this aforementioned table, setting the CSL registers
>> according to the table. However, this loop loops on CSL index values > 0:
>> while (csu_setting->csu_index *>* 0) {
>> io_write32(csu_base + (csu_setting->csu_index * 4),
>> csu_setting->value);
>>
>> csu_setting++;
>> }
>> I think it should loop on CSL index values >= 0, because index 0 is a valid
>> index, utilized for the PWM peripherals. (I also think csl_index is a more
>> descriptive name, but that's besides the point).
>>
>> I have attached a patch for his.
>
> It does look like a genuine bug to me, but I will let the i.MX expert
> comment further. Unfortunately, the OP-TEE ML strips attachments. Would
> you mind creating a GitHub pull request [1] (preferred method), or send
> the patch inline?
>
> [1] https://github.com/OP-TEE/optee_os/pulls
>
> Thanks,
>
https://github.com/OP-TEE/optee_os/pull/4511
Hi Sandeep,
I just noticed that your PR is abandoned. Will you resend your PR?
Thanks,
Peng.
________________________________
From: OP-TEE <op-tee-bounces(a)lists.trustedfirmware.org> on behalf of Peng Fan via OP-TEE <op-tee(a)lists.trustedfirmware.org>
Sent: Tuesday, March 23, 2021 10:14 AM
To: Sandeep Tripathy <sandeep.tripathy(a)broadcom.com>
Cc: tf-a(a)lists.trustedfirmware.org <tf-a(a)lists.trustedfirmware.org>; op-tee(a)lists.trustedfirmware.org <op-tee(a)lists.trustedfirmware.org>
Subject: RE: [TF-A] EHF + OPTEE on ARM64
Hi Sandeep
> Subject: Re: [TF-A] EHF + OPTEE on ARM64
>
> Hi Peng,
>
> 1-Asynchronous preemption of SP:
> The long route is to make changes in the dispatcher and the
> corresponding SPD implementation to have synchronous preemption.
> ie: OP-TEE dispatcher will implement a G1NS (fiq) handler and invoke
> an entry of OP-TEE synchronously. OP-TEE will save the thread context
> and return.
> I did some POC but the complexity and effort to generalise was not
> justified by our requirement at that point especially envisioning the
> movement to SPMD in future.
>
> 2-Synchronous preemption of SP:
> ref:
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Freview.tr…
>
> I used this approach instead to unblock OP-TEE work alongside EHF.
> This serves the purpose without changing the routing model with a
> limitation that non yielding/fast SMC can
> not be preempted. And ofcourse OP-TEE can mask G0 interrupt in
> anycase. But I think this is sufficient for your purpose.
>
> Please feedback if the above patch works for you.
I was trying using #ifndef SPD_opteed to wrap the secure stuff. Thanks
for your patch. I test on i.MX8MM-EVK, it works well.
Thanks,
Peng.
>
> Thanks
> Sandeep
>
> On Mon, Mar 22, 2021 at 2:43 PM Peng Fan via TF-A
> <tf-a(a)lists.trustedfirmware.org> wrote:
> >
> > Hi Achin,
> >
> >
> >
> > We are using SDEI for Jailhouse hypervisor to minimize interrupt latency,
> however we also wanna use OP-TEE when SDEI enabled.
> >
> >
> >
> > So I wanna how to make both work together.
> >
> >
> >
> > Thanks,
> >
> > Peng.
> >
> >
> >
> > From: Achin Gupta [mailto:Achin.Gupta@arm.com]
> > Sent: 2021年3月17日 17:59
> > To: Peng Fan <peng.fan(a)nxp.com>; Jens Wiklander
> <jens.wiklander(a)linaro.org>
> > Cc: op-tee(a)lists.trustedfirmware.org; tf-a(a)lists.trustedfirmware.org
> > Subject: Re: EHF + OPTEE on ARM64
> >
> >
> >
> > Hi Peng,
> >
> >
> >
> > +TF-A folk.
> >
> >
> >
> > My 0.02$.
> >
> >
> >
> > What is the problem you are trying to solve? Why do you need to run
> OP-TEE and EHF together? EHF was originally written to support a S-EL0 SP
> that is managed directly by TF-A in EL3 (TF-A folk can chime in).
> >
> >
> >
> > The SP could perform RAS error handling for which it needs the EHF. The EHF
> triages asynchronous exceptions and hands RAS errors to the SP for further
> handling.
> >
> >
> >
> > This is just one use case but there is no Trusted OS in these configurations.
> >
> >
> >
> > So, it would help to understand the requirement.
> >
> >
> >
> > cheers,
> >
> > Achin
> >
> >
> >
> > ________________________________
> >
> > From: OP-TEE <op-tee-bounces(a)lists.trustedfirmware.org> on behalf of
> Jens Wiklander via OP-TEE <op-tee(a)lists.trustedfirmware.org>
> > Sent: 17 March 2021 09:23
> > To: Peng Fan <peng.fan(a)nxp.com>
> > Cc: op-tee(a)lists.trustedfirmware.org <op-tee(a)lists.trustedfirmware.org>
> > Subject: Re: EHF + OPTEE on ARM64
> >
> >
> >
> > On Wed, Mar 17, 2021 at 9:43 AM Peng Fan <peng.fan(a)nxp.com> wrote:
> > >
> > > > Subject: Re: EHF + OPTEE on ARM64
> > > >
> > > > On Wed, Mar 17, 2021 at 9:02 AM Peng Fan <peng.fan(a)nxp.com>
> wrote:
> > > > >
> > > > > > Subject: Re: EHF + OPTEE on ARM64
> > > > > >
> > > > > > On Wed, Mar 17, 2021 at 8:41 AM Peng Fan <peng.fan(a)nxp.com>
> wrote:
> > > > > > >
> > > > > > > > Subject: Re: EHF + OPTEE on ARM64
> > > > > > > >
> > > > > > > > On Tue, Mar 16, 2021 at 11:08 AM Peng Fan
> <peng.fan(a)nxp.com>
> > > > wrote:
> > > > > > > > >
> > > > > > > > > Hi,
> > > > > > > > >
> > > > > > > > > In bl31/ehf.c, there are following two lines, per my
> > > > > > > > > understanding, when cpu is in secure world, the non-secure
> > > > > > > > > interrupt as FIQ(GICv3) will be directly catched by EL3, not
> S-EL1
> > > > > > > > > /* Route EL3 interrupts when in Secure and
> Non-secure.
> > > > */
> > > > > > > > > set_interrupt_rm_flag(flags, NON_SECURE);
> > > > > > > > > set_interrupt_rm_flag(flags, SECURE);
> > > > > > > > >
> > > > > > > > > So this will conflict with OP-TEE, because OP-TEE needs catch
> > > > > > > > > NS-interrupt as FIQ in S-EL1 world.
> > > > > > > >
> > > > > > > > In the case of GICv3, OP-TEE is configured to receive the
> > > > > > > > non-secure interrupts as FIQ and secure interrupts as IRQ. See
> > > > CFG_ARM_GICV3.
> > > > > > >
> > > > > > > But EHF needs NS-interrupt FIQ be catched by EL3 if I understand
> > > > > > > correct, per " set_interrupt_rm_flag(flags, SECURE);"
> > > > > > >
> > > > > > > So currently EHF could not work together with OP-TEE, right?
> > > > > >
> > > > > > To be honest, I'm not completely sure what EHF does. From OP-TEE
> > > > > > point of view we expect to receive the non-secure interrupts as a
> > > > > > way of doing a controlled exit. This allows OP-TEE to resume
> > > > > > execution with a different core on re-entry. If EL3 takes the
> > > > > > non-secure interrupts directly it will have to make sure to only
> re-enter
> > > > OP-TEE on this core as a return from exception.
> > > > >
> > > > > Is this easy to be achieved?
> > > >
> > > > I don't know, it depends on what you intend to do with this non-secure
> > > > interrupt. If it's handled at EL3 and then there's a return from exception
> back
> > > > to S-EL1 there's likely no harm done. But if there's a world switch
> involved
> > > > there might be trouble, OP-TEE might not be in a suitable state for a
> world
> > > > switch.
> > > >
> > > > >
> > > > > Or by using opteed_sel1_interrupt_handler, could we have similar
> > > > > behavior to allow the other core resume execution?
> > > >
> > > > Only OP-TEE itself can make a controlled exit as there's an internal state
> to
> > > > maintain. Currently that's signalled with a non-secure interrupt.
> > >
> > >
> > > Per EHF,
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftrustedfi…
> andling.html?highlight=Exception%20Handling%20Framework
> > > On GICv3 systems, when executing in S-EL1, pending Non-secure
> interrupts of
> > > sufficient priority are signalled as FIQs, and therefore will be routed to
> EL3.
> > > As a result, S-EL1 software cannot expect to handle Non-secure interrupts
> at S-EL1.
> > > Essentially, this deprecates the routing mode described as CSS=0, TEL3=0.
> > >
> > > In order for S-EL1 software to handle Non-secure interrupts while having
> EHF enabled,
> > > the dispatcher must adopt a model where Non-secure interrupts are
> received at EL3,
> > > but are then synchronously handled over to S-EL1.
> > >
> > > The issue to me here how to synchronously handled over to S-EL1 and not
> break optee.
> >
> > I understand. OP-TEE is masking interrupts in some critical sections,
> > while in such a state OP-TEE cannot handle any asynchronous interrupt.
> > Temporarily masking interrupts is normally a quick operation so we do
> > it in quite a few places.
> > So the crux of the problem is to make sure that OP-TEE is in a state
> > where it can make a controlled exit. I don't have any good ideas for
> > this right now.
> >
> > Cheers,
> > Jens
> >
> > --
> > TF-A mailing list
> > TF-A(a)lists.trustedfirmware.org
> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.tru…
Hi all,
This adds supports for the OP-TEE driver to communicate with secure world
using FF-A [1] as transport.
These patches are based on the FF-A v4 patch set by Sudeep Holla [2] [3].
There is one change to the TEE subsystem with "tee: add sec_world_id to
struct tee_shm" to add support for holding globally unique handle assigned
by the FF-A. This is a field that I believe could useful for the AMDTEE
driver too.
For communication the OP-TEE message protocol is still used, but with a new
type of memory reference, struct optee_msg_param_fmem, to carry the
information needed by FF-A. The OP-TEE driver is refactored internally with
to sets of callbacks, one for the old SMC based communication and another
set with FF-A as transport.
There is also a difference in how the drivers are instantiated. With the
SMC based transport we have a platform driver, module_platform_driver(),
today which we're keeping as is for this configuration. In a FF-A system we
have a FF-A driver, module_ffa_driver(), instead.
The OP-TEE driver can be compiled for both targets at the same time and
it's up to runtime configuration (device tree or ACPI) to decide how it's
initialized.
Thanks,
Jens
[1] https://developer.arm.com/documentation/den0077/latest
[2] https://lore.kernel.org/linux-arm-kernel/20210212154614.38604-1-sudeep.holl…
[3] git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux.git v5.11/ffa
Jens Wiklander (6):
tee: add sec_world_id to struct tee_shm
optee: simplify optee_release()
optee: sync optee_msg.h and optee_rpc_cmd.h
optee: refactor driver with internal callbacks
optee: add a FF-A memory pool
optee: add FF-A support
drivers/tee/optee/call.c | 327 +++++++++++---
drivers/tee/optee/core.c | 698 +++++++++++++++++++++++++-----
drivers/tee/optee/optee_ffa.h | 153 +++++++
drivers/tee/optee/optee_msg.h | 168 ++-----
drivers/tee/optee/optee_private.h | 88 +++-
drivers/tee/optee/optee_rpc_cmd.h | 333 ++++++++++++++
drivers/tee/optee/rpc.c | 169 +++++++-
drivers/tee/optee/shm_pool.c | 65 ++-
drivers/tee/optee/shm_pool.h | 1 +
include/linux/tee_drv.h | 7 +-
10 files changed, 1685 insertions(+), 324 deletions(-)
create mode 100644 drivers/tee/optee/optee_ffa.h
create mode 100644 drivers/tee/optee/optee_rpc_cmd.h
base-commit: 31ef391700953fb59ea8755ea38c6085bdec380e
--
2.25.1
Hello arm-soc maintainers,
Please pull this patch adding tracepoints around calls to OP-TEE in
secure world.
Thanks,
Jens
The following changes since commit a38fd8748464831584a19438cbb3082b5a2dab15:
Linux 5.12-rc2 (2021-03-05 17:33:41 -0800)
are available in the Git repository at:
git://git.linaro.org/people/jens.wiklander/linux-tee.git tags/optee-tracepoints-for-v5.13
for you to fetch changes up to 0101947dbcc3204f08fb5b69a21dbd4b1535cad6:
tee: optee: add invoke_fn tracepoints (2021-03-15 12:04:01 +0100)
----------------------------------------------------------------
Add tracepoints around calls to secure world
----------------------------------------------------------------
Jisheng Zhang (1):
tee: optee: add invoke_fn tracepoints
drivers/tee/optee/call.c | 4 +++
drivers/tee/optee/optee_trace.h | 67 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 71 insertions(+)
create mode 100644 drivers/tee/optee/optee_trace.h
Hi,
LOC monthly meeting is planned to take place Thursday March 25th(a)16.00
(UTC+1).
Current topics on the agenda are:
- RNG in OP-TEE: This was proposed by Jorge for Foundries.io who created a
couple of patches in a pull request. However he's unable to continue
working with that, but no matter it's a good discussion, so I've left it on
the agenda.
- OCALL: Then there has been a patch set / PR: OCALL pull request, Jerome
wanted to discuss what the next steps are.
There is most likely room for additional topics, so feel free to suggest.
Meeting details:
---------------
Date/time: Thursday March 25th(a)16.00 (UTC+1)
https://everytimezone.com/s/3596d6d3
Connection details: https://www.trustedfirmware.org/meetings/
Meeting notes: http://bit.ly/loc-notes
Project page: https://www.linaro.org/projects/#LOC
Regards,
Joakim on behalf of the Linaro OP-TEE team
Hi Peng,
1-Asynchronous preemption of SP:
The long route is to make changes in the dispatcher and the
corresponding SPD implementation to have synchronous preemption.
ie: OP-TEE dispatcher will implement a G1NS (fiq) handler and invoke
an entry of OP-TEE synchronously. OP-TEE will save the thread context
and return.
I did some POC but the complexity and effort to generalise was not
justified by our requirement at that point especially envisioning the
movement to SPMD in future.
2-Synchronous preemption of SP:
ref:
https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/6345
I used this approach instead to unblock OP-TEE work alongside EHF.
This serves the purpose without changing the routing model with a
limitation that non yielding/fast SMC can
not be preempted. And ofcourse OP-TEE can mask G0 interrupt in
anycase. But I think this is sufficient for your purpose.
Please feedback if the above patch works for you.
Thanks
Sandeep
On Mon, Mar 22, 2021 at 2:43 PM Peng Fan via TF-A
<tf-a(a)lists.trustedfirmware.org> wrote:
>
> Hi Achin,
>
>
>
> We are using SDEI for Jailhouse hypervisor to minimize interrupt latency, however we also wanna use OP-TEE when SDEI enabled.
>
>
>
> So I wanna how to make both work together.
>
>
>
> Thanks,
>
> Peng.
>
>
>
> From: Achin Gupta [mailto:Achin.Gupta@arm.com]
> Sent: 2021年3月17日 17:59
> To: Peng Fan <peng.fan(a)nxp.com>; Jens Wiklander <jens.wiklander(a)linaro.org>
> Cc: op-tee(a)lists.trustedfirmware.org; tf-a(a)lists.trustedfirmware.org
> Subject: Re: EHF + OPTEE on ARM64
>
>
>
> Hi Peng,
>
>
>
> +TF-A folk.
>
>
>
> My 0.02$.
>
>
>
> What is the problem you are trying to solve? Why do you need to run OP-TEE and EHF together? EHF was originally written to support a S-EL0 SP that is managed directly by TF-A in EL3 (TF-A folk can chime in).
>
>
>
> The SP could perform RAS error handling for which it needs the EHF. The EHF triages asynchronous exceptions and hands RAS errors to the SP for further handling.
>
>
>
> This is just one use case but there is no Trusted OS in these configurations.
>
>
>
> So, it would help to understand the requirement.
>
>
>
> cheers,
>
> Achin
>
>
>
> ________________________________
>
> From: OP-TEE <op-tee-bounces(a)lists.trustedfirmware.org> on behalf of Jens Wiklander via OP-TEE <op-tee(a)lists.trustedfirmware.org>
> Sent: 17 March 2021 09:23
> To: Peng Fan <peng.fan(a)nxp.com>
> Cc: op-tee(a)lists.trustedfirmware.org <op-tee(a)lists.trustedfirmware.org>
> Subject: Re: EHF + OPTEE on ARM64
>
>
>
> On Wed, Mar 17, 2021 at 9:43 AM Peng Fan <peng.fan(a)nxp.com> wrote:
> >
> > > Subject: Re: EHF + OPTEE on ARM64
> > >
> > > On Wed, Mar 17, 2021 at 9:02 AM Peng Fan <peng.fan(a)nxp.com> wrote:
> > > >
> > > > > Subject: Re: EHF + OPTEE on ARM64
> > > > >
> > > > > On Wed, Mar 17, 2021 at 8:41 AM Peng Fan <peng.fan(a)nxp.com> wrote:
> > > > > >
> > > > > > > Subject: Re: EHF + OPTEE on ARM64
> > > > > > >
> > > > > > > On Tue, Mar 16, 2021 at 11:08 AM Peng Fan <peng.fan(a)nxp.com>
> > > wrote:
> > > > > > > >
> > > > > > > > Hi,
> > > > > > > >
> > > > > > > > In bl31/ehf.c, there are following two lines, per my
> > > > > > > > understanding, when cpu is in secure world, the non-secure
> > > > > > > > interrupt as FIQ(GICv3) will be directly catched by EL3, not S-EL1
> > > > > > > > /* Route EL3 interrupts when in Secure and Non-secure.
> > > */
> > > > > > > > set_interrupt_rm_flag(flags, NON_SECURE);
> > > > > > > > set_interrupt_rm_flag(flags, SECURE);
> > > > > > > >
> > > > > > > > So this will conflict with OP-TEE, because OP-TEE needs catch
> > > > > > > > NS-interrupt as FIQ in S-EL1 world.
> > > > > > >
> > > > > > > In the case of GICv3, OP-TEE is configured to receive the
> > > > > > > non-secure interrupts as FIQ and secure interrupts as IRQ. See
> > > CFG_ARM_GICV3.
> > > > > >
> > > > > > But EHF needs NS-interrupt FIQ be catched by EL3 if I understand
> > > > > > correct, per " set_interrupt_rm_flag(flags, SECURE);"
> > > > > >
> > > > > > So currently EHF could not work together with OP-TEE, right?
> > > > >
> > > > > To be honest, I'm not completely sure what EHF does. From OP-TEE
> > > > > point of view we expect to receive the non-secure interrupts as a
> > > > > way of doing a controlled exit. This allows OP-TEE to resume
> > > > > execution with a different core on re-entry. If EL3 takes the
> > > > > non-secure interrupts directly it will have to make sure to only re-enter
> > > OP-TEE on this core as a return from exception.
> > > >
> > > > Is this easy to be achieved?
> > >
> > > I don't know, it depends on what you intend to do with this non-secure
> > > interrupt. If it's handled at EL3 and then there's a return from exception back
> > > to S-EL1 there's likely no harm done. But if there's a world switch involved
> > > there might be trouble, OP-TEE might not be in a suitable state for a world
> > > switch.
> > >
> > > >
> > > > Or by using opteed_sel1_interrupt_handler, could we have similar
> > > > behavior to allow the other core resume execution?
> > >
> > > Only OP-TEE itself can make a controlled exit as there's an internal state to
> > > maintain. Currently that's signalled with a non-secure interrupt.
> >
> >
> > Per EHF, https://trustedfirmware-a.readthedocs.io/en/latest/components/exception-han…
> > On GICv3 systems, when executing in S-EL1, pending Non-secure interrupts of
> > sufficient priority are signalled as FIQs, and therefore will be routed to EL3.
> > As a result, S-EL1 software cannot expect to handle Non-secure interrupts at S-EL1.
> > Essentially, this deprecates the routing mode described as CSS=0, TEL3=0.
> >
> > In order for S-EL1 software to handle Non-secure interrupts while having EHF enabled,
> > the dispatcher must adopt a model where Non-secure interrupts are received at EL3,
> > but are then synchronously handled over to S-EL1.
> >
> > The issue to me here how to synchronously handled over to S-EL1 and not break optee.
>
> I understand. OP-TEE is masking interrupts in some critical sections,
> while in such a state OP-TEE cannot handle any asynchronous interrupt.
> Temporarily masking interrupts is normally a quick operation so we do
> it in quite a few places.
> So the crux of the problem is to make sure that OP-TEE is in a state
> where it can make a controlled exit. I don't have any good ideas for
> this right now.
>
> Cheers,
> Jens
>
> --
> TF-A mailing list
> TF-A(a)lists.trustedfirmware.org
> https://lists.trustedfirmware.org/mailman/listinfo/tf-a
When Secure World returns, it may have changed the size attribute of the
memory references passed as [in/out] parameters. The GlobalPlatform TEE
Internal Core API specification does not restrict the values that this
size can take. In particular, Secure World may increase the value to be
larger than the size of the input buffer to indicate that it needs more.
Therefore, the size check in optee_from_msg_param() is incorrect and
needs to be removed. This fixes a number of failed test cases in the
GlobalPlatform TEE Initial Configuratiom Test Suite v2_0_0_0-2017_06_09
when OP-TEE is compiled without dynamic shared memory support
(CFG_CORE_DYN_SHM=n).
Suggested-by: Jens Wiklander <jens.wiklander(a)linaro.org>
Signed-off-by: Jerome Forissier <jerome(a)forissier.org>
---
drivers/tee/optee/core.c | 10 ----------
1 file changed, 10 deletions(-)
diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
index 319a1e701163..ddb8f9ecf307 100644
--- a/drivers/tee/optee/core.c
+++ b/drivers/tee/optee/core.c
@@ -79,16 +79,6 @@ int optee_from_msg_param(struct tee_param *params, size_t num_params,
return rc;
p->u.memref.shm_offs = mp->u.tmem.buf_ptr - pa;
p->u.memref.shm = shm;
-
- /* Check that the memref is covered by the shm object */
- if (p->u.memref.size) {
- size_t o = p->u.memref.shm_offs +
- p->u.memref.size - 1;
-
- rc = tee_shm_get_pa(shm, o, NULL);
- if (rc)
- return rc;
- }
break;
case OPTEE_MSG_ATTR_TYPE_RMEM_INPUT:
case OPTEE_MSG_ATTR_TYPE_RMEM_OUTPUT:
--
2.25.1
Hi Peng,
+TF-A folk.
My 0.02$.
What is the problem you are trying to solve? Why do you need to run OP-TEE and EHF together? EHF was originally written to support a S-EL0 SP that is managed directly by TF-A in EL3 (TF-A folk can chime in).
The SP could perform RAS error handling for which it needs the EHF. The EHF triages asynchronous exceptions and hands RAS errors to the SP for further handling.
This is just one use case but there is no Trusted OS in these configurations.
So, it would help to understand the requirement.
cheers,
Achin
________________________________
From: OP-TEE <op-tee-bounces(a)lists.trustedfirmware.org> on behalf of Jens Wiklander via OP-TEE <op-tee(a)lists.trustedfirmware.org>
Sent: 17 March 2021 09:23
To: Peng Fan <peng.fan(a)nxp.com>
Cc: op-tee(a)lists.trustedfirmware.org <op-tee(a)lists.trustedfirmware.org>
Subject: Re: EHF + OPTEE on ARM64
On Wed, Mar 17, 2021 at 9:43 AM Peng Fan <peng.fan(a)nxp.com> wrote:
>
> > Subject: Re: EHF + OPTEE on ARM64
> >
> > On Wed, Mar 17, 2021 at 9:02 AM Peng Fan <peng.fan(a)nxp.com> wrote:
> > >
> > > > Subject: Re: EHF + OPTEE on ARM64
> > > >
> > > > On Wed, Mar 17, 2021 at 8:41 AM Peng Fan <peng.fan(a)nxp.com> wrote:
> > > > >
> > > > > > Subject: Re: EHF + OPTEE on ARM64
> > > > > >
> > > > > > On Tue, Mar 16, 2021 at 11:08 AM Peng Fan <peng.fan(a)nxp.com>
> > wrote:
> > > > > > >
> > > > > > > Hi,
> > > > > > >
> > > > > > > In bl31/ehf.c, there are following two lines, per my
> > > > > > > understanding, when cpu is in secure world, the non-secure
> > > > > > > interrupt as FIQ(GICv3) will be directly catched by EL3, not S-EL1
> > > > > > > /* Route EL3 interrupts when in Secure and Non-secure.
> > */
> > > > > > > set_interrupt_rm_flag(flags, NON_SECURE);
> > > > > > > set_interrupt_rm_flag(flags, SECURE);
> > > > > > >
> > > > > > > So this will conflict with OP-TEE, because OP-TEE needs catch
> > > > > > > NS-interrupt as FIQ in S-EL1 world.
> > > > > >
> > > > > > In the case of GICv3, OP-TEE is configured to receive the
> > > > > > non-secure interrupts as FIQ and secure interrupts as IRQ. See
> > CFG_ARM_GICV3.
> > > > >
> > > > > But EHF needs NS-interrupt FIQ be catched by EL3 if I understand
> > > > > correct, per " set_interrupt_rm_flag(flags, SECURE);"
> > > > >
> > > > > So currently EHF could not work together with OP-TEE, right?
> > > >
> > > > To be honest, I'm not completely sure what EHF does. From OP-TEE
> > > > point of view we expect to receive the non-secure interrupts as a
> > > > way of doing a controlled exit. This allows OP-TEE to resume
> > > > execution with a different core on re-entry. If EL3 takes the
> > > > non-secure interrupts directly it will have to make sure to only re-enter
> > OP-TEE on this core as a return from exception.
> > >
> > > Is this easy to be achieved?
> >
> > I don't know, it depends on what you intend to do with this non-secure
> > interrupt. If it's handled at EL3 and then there's a return from exception back
> > to S-EL1 there's likely no harm done. But if there's a world switch involved
> > there might be trouble, OP-TEE might not be in a suitable state for a world
> > switch.
> >
> > >
> > > Or by using opteed_sel1_interrupt_handler, could we have similar
> > > behavior to allow the other core resume execution?
> >
> > Only OP-TEE itself can make a controlled exit as there's an internal state to
> > maintain. Currently that's signalled with a non-secure interrupt.
>
>
> Per EHF, https://trustedfirmware-a.readthedocs.io/en/latest/components/exception-han…
> On GICv3 systems, when executing in S-EL1, pending Non-secure interrupts of
> sufficient priority are signalled as FIQs, and therefore will be routed to EL3.
> As a result, S-EL1 software cannot expect to handle Non-secure interrupts at S-EL1.
> Essentially, this deprecates the routing mode described as CSS=0, TEL3=0.
>
> In order for S-EL1 software to handle Non-secure interrupts while having EHF enabled,
> the dispatcher must adopt a model where Non-secure interrupts are received at EL3,
> but are then synchronously handled over to S-EL1.
>
> The issue to me here how to synchronously handled over to S-EL1 and not break optee.
I understand. OP-TEE is masking interrupts in some critical sections,
while in such a state OP-TEE cannot handle any asynchronous interrupt.
Temporarily masking interrupts is normally a quick operation so we do
it in quite a few places.
So the crux of the problem is to make sure that OP-TEE is in a state
where it can make a controlled exit. I don't have any good ideas for
this right now.
Cheers,
Jens