Travis' and Gelas' TRMs tell us to disable SME (set PSTATE.{ZA, SM} to
0) when we're attempting to power down. What they don't tell us is that
if this isn't done, the powerdown request will be rejected. On the
CPU_OFF path that's not a problem - we can force SVCR to 0 and be
certain the core will power off.
On the suspend to powerdown path, however, we cannot do this. The TRM
also tells us that the sequence could also be aborted on eg. GIC
interrupts. If this were to happen when we have overwritten SVCR to 0,
upon a return to the caller they would experience a loss of context. We
know that at least Linux may call into PSCI with SVCR != 0. One option
is to save the entire SME context which would be quite expensive just to
work around. Another option is to downgrade the request to a normal
suspend when SME was left on. This option is better as this is expected
to happen rarely enough to ignore the wasted power and we don't want to
burden the generic (correct) path with needless context management.
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Change-Id: I698fa8490ebf51461f6aa8bba84f9827c5c46ad4
The simplistic view of a core's powerdown sequence is that power is
atomically cut upon calling `wfi`. However, it turns out that it has
lots to do - it has to talk to the interconnect to exit coherency, clean
caches, check for RAS errors, etc. These take significant amounts of
time and are certainly not atomic. As such there is a significant window
of opportunity for external events to happen. Many of these steps are
not destructive to context, so theoretically, the core can just "give
up" half way (or roll certain actions back) and carry on running. The
point in this sequence after which roll back is not possible is called
the point of no return.
One of these actions is the checking for RAS errors. It is possible for
one to happen during this lengthy sequence, or at least remain
undiscovered until that point. If the core were to continue powerdown
when that happens, there would be no (easy) way to inform anyone about
it. Rejecting the powerdown and letting software handle the error is the
best way to implement this.
Arm cores since at least the a510 have included this exact feature. So
far it hasn't been deemed necessary to account for it in firmware due to
the low likelihood of this happening. However, events like GIC wakeup
requests are much more probable. Older cores will powerdown and
immediately power back up when this happens. Travis and Gelas include a
feature similar to the RAS case above, called powerdown abandon. The
idea is that this will improve the latency to service the interrupt by
saving on work which the core and software need to do.
So far firmware has relied on the `wfi` being the point of no return and
if it doesn't explicitly detect a pending interrupt quite early on, it
will embark onto a sequence that it expects to end with shutdown. To
accommodate for it not being a point of no return, we must undo all of
the system management we did, just like in the warm boot entrypoint.
To achieve that, the pwr_domain_pwr_down_wfi hook must not be terminal.
Most recent platforms do some platform management and finish on the
standard `wfi`, followed by a panic or an endless loop as this is
expected to not return. To make this generic, any platform that wishes
to support wakeups must instead let common code call
`psci_power_down_wfi()` right after. Besides wakeups, this lets common
code handle powerdown errata better as well.
Then, the CPU_OFF case is simple - PSCI does not allow it to return. So
the best that can be done is to attempt the `wfi` a few times (the
choice of 32 is arbitrary) in the hope that the wakeup is transient. If
it isn't, the only choice is to panic, as the system is likely to be in
a bad state, eg. interrupts weren't routed away. The same applies for
SYSTEM_OFF, SYSTEM_RESET, and SYSTEM_RESET2. There the panic won't
matter as the system is going offline one way or another. The RAS case
will be considered in a separate patch.
Now, the CPU_SUSPEND case is more involved. First, to powerdown it must
wipe its context as it is not written on warm boot. But it cannot be
overwritten in case of a wakeup. To avoid the catch 22, save a copy that
will only be used if powerdown fails. That is about 500 bytes on the
stack so it hopefully doesn't tip anyone over any limits. In future that
can be avoided by having a core manage its own context.
Second, when the core wakes up, it must undo anything it did to prepare
for poweroff, which for the cores we care about, is writing
CPUPWRCTLR_EL1.CORE_PWRDN_EN. The least intrusive for the cpu library
way of doing this is to simply call the power off hook again and have
the hook toggle the bit. If in the future there need to be more complex
sequences, their direction can be advised on the value of this bit.
Third, do the actual "resume". Most of the logic is already there for
the retention suspend, so that only needs a small touch up to apply to
the powerdown case as well. The missing bit is the powerdown specific
state management. Luckily, the warmboot entrypoint does exactly that
already too, so steal that and we're done.
All of this is hidden behind a FEAT_PABANDON flag since it has a large
memory and runtime cost that we don't want to burden non pabandon cores
with.
Finally, do some function renaming to better reflect their purpose and
make names a little bit more consistent.
Change-Id: I2405b59300c2e24ce02e266f91b7c51474c1145f
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
The workarounds introduced in the three patches starting at
888eafa00b assumed that any powerdown
request will be (forced to be) terminal. This assumption can no longer
be the case for new CPUs so there is a need to revisit these older
cores. Since we may wake up, we now need to respect the workaround's
recommendation that the workaround needs to be reverted on wakeup. So do
exactly that.
Introduce a new helper to toggle bits in assembly. This allows us to
call the workaround twice, with the first call setting the workaround
and second undoing it. This is also used for gelas' an travis' powerdown
routines. This is so the same function can be called again
Also fix the condition in the cpu helper macro as it was subtly wrong
Change-Id: Iff9e5251dc9d8670d085d88c070f78991955e7c3
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Introduce a new helper to toggle bits in assembly. This allows us to
call the workaround twice, with the first call setting the workaround
and second undoing it. This allows the (errata) workaround functions to
be used to both apply and undo the mitigation.
This is applied to functions where the undo part will be required in
follow-up patches.
Change-Id: I058bad58f5949b2d5fe058101410e33b6be1b8ba
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
This patch implements SMCCC_ARCH_WORKAROUND_4 and
allows discovery through SMCCC_ARCH_FEATURES.
This mechanism is enabled if CVE_2024_7881 [1] is enabled
by the platform. If CVE_2024_7881 mitigation
is implemented, the discovery call returns 0,
if not -1 (SMC_ARCH_CALL_NOT_SUPPORTED).
For more information about SMCCC_ARCH_WORKAROUND_4 [2], please
refer to the SMCCC Specification reference provided below.
[1]: https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-7881
[2]: https://developer.arm.com/documentation/den0028/latest
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: I1b1ffaa1f806f07472fd79d5525f81764d99bc79
MDCR_EL3 register will context switch across all worlds. Thus the pmuv3
init has to be part of context management initialization.
Change-Id: I10ef7a3071c0fc5c11a93d3c9c2a95ec8c6493bf
Signed-off-by: Mateusz Sulimowicz <matsul@google.com>
* changes:
perf(psci): pass my_core_pos around instead of calling it repeatedly
refactor(psci): move timestamp collection to psci_pwrdown_cpu
refactor(psci): factor common code out of the standby finisher
refactor(psci): don't use PSCI_INVALID_PWR_LVL to signal OFF state
docs(psci): drop outdated cache maintenance comment
FEAT_MOPS, mandatory from Arm v8.8, is typically managed in EL2.
However, in configurations where NS_EL2 is not enabled,
EL3 must set the HCRX_EL2.MSCEn bit to 1 to enable the feature.
This patch ensures FEAT_MOPS is enabled by setting HCRX_EL2.MSCEn to 1.
Change-Id: Ic4960e0cc14a44279156b79ded50de475b3b21c5
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
On some platforms plat_my_core_pos is a nontrivial function that takes a
bit of time and the compiler really doesn't like to inline. In the PSCI
library, at least, we have no need to keep repeatedly calling it and we
can instead pass it around as an argument. This saves on a lot of
redundant calls, speeding the library up a bit.
Change-Id: I137f69bea80d7cac90d7a20ffe98e1ba8d77246f
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
psci_pwrdown_cpu has two callers, both of which save timestamps meant to
measure how much time the cache maintenance operations take. Move the
timestamp collection inside to save on a bit of code duplication.
Change-Id: Ia2e7168faf7773d99b696cbdb6c98db7b58e31cf
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
psci_suspend_to_standby_finisher and psci_cpu_suspend_finish do mostly
the same stuff, besides the system management associated with their
respective wakeup paths. So bring the wake from standby path in line
with the wake from reset path - caller acquires locks and manages
context. This way both behave in vaguely the same way. We can also bring
their names in line so it's more apparent how they are different.
This is in preparation for cores waking from sleep, coming in another
patch. No functional change is expected.
Change-Id: I0e569d12f65d231606080faa0149d22efddc386d
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
The target_pwrlvl field in the psci cpu data struct only stores the
highest power domain that a CPU_SUSPEND call affected, and is used to
resume those same domains on warm reset. If the cpu is otherwise OFF
(never turned on or CPU_OFF), then this needs to be the highest power
level because we don't know the highest level that will be off.
So skip the invalidation and always keep the field to the maximum value.
During suspend the field will be lowered to the appropriate value and
then put back after wakeup.
Also, do that in the suspend to standby path as well as it will have
been written before the sleep and it might end up incorrect.
Change-Id: I614272ec387e1d83023c94700780a0f538a9a6b6
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
The comment was written when cache maintenance had to be considered when
calling this function. But that argument was dropped a while back and
this comment no longer makes any sense.
Change-Id: Ib68293f23cc3edca3010164dfe8866956b8e1a63
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Patch fc7dca72ba656e5f147487b20f9f0fb6eb39e116 changed the owning
security states of the TRBE and SPE buffers to NS. The thinking was that
this would assist SMCCC feature availability to more easily determine
if the feature is enabled or disabled. However, that only changed bit 0
while the SMCCC feature only looks at bit 1 so this change is redundant.
It was also meant to tighten security but that was done by
73d98e3759 instead.
Annoyingly, FEAT_TRBE has TRBIDR_EL1 which reports that programming is
allowed when the current security state owns the buffer even when the
MDCR_EL3 setting disallows this in practice.
So revert the functional aspect of the patch as it causes linux panics
with ERRATA_A520_2938996. Keep the defines as they are used elsewhere.
Change-Id: I39463d585df89aee44d1996137616da85d678f41
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
In preparation for SMCCC_ARCH_FEATURE_AVAILABILITY, it is useful for
context to be directly related to the underlying system. Currently,
certain bits like SCR_EL3.APK are always set with the understanding that
they will only take effect if the feature is present.
However, that is problematic for SMCCC_ARCH_FEATURE_AVAILABILITY (an
SMCCC call to report which features firmware enables), as simply reading
the enable bit may contradict the ID register, like the APK bit above
for a system with no Pauth present.
This patch is to clean up these cases. Add a check for PAuth's presence
so that the APK bit remains unset if not present. Also move SPE and TRBE
enablement to only the NS context. They already only enable the features
for NS only and disable them for Secure and Realm worlds. This change
only makes these worlds' context read 0 for easy bitmasking.
There's only a single snag on SPE and TRBE. Currently, their fields have
the same values and any world asymmetry is handled by hardware. Since we
don't want to do that, the buffers' ownership will change if we just set
the fields to 0 for non-NS worlds. Doing that, however, exposes Secure
state to a potential denial of service attack - a malicious NS can
enable profiling and call an SMC. Then, the owning security state will
change and since no SPE/TRBE registers are contexted, Secure state will
start generating records. Always have NS world own the buffers to
prevent this.
Finally, get rid of manage_extensions_common() as it's just a level of
indirection to enable a single feature.
Change-Id: I487bd4c70ac3e2105583917a0e5499e0ee248ed9
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
SPE and TRBE don't have an outright EL3 disable, there are only
constraints on what's allowed. Since we only enable them for NS at the
moment, we want NS to own the buffers even when the feature should be
"disabled" for a world. This means that when we're running in NS
everything is as normal but when running in S/RL then tracing is
prohibited (since the buffers are owned by NS). This allows us to fiddle
with context a bit more without having to context switch registers.
Change-Id: Ie1dc7c00e4cf9bcc746f02ae43633acca32d3758
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Our implementation of printf does not support flag format specifiers.
Our previous format specification as a result was causing the integer
values to be omitted. This change updates the formatting to ensure
accurate and complete error messages are displayed.
Change-Id: I80cfb5fd7ff26e44cfad4e06803d9e0912488136
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
Add a function to check whether a transfer list has been initialized
at the input address. If not, initialize a transfer list at the
specified location with the given size. This is to help ensure that we
don't accidently overwrite a transfer list that's been passed from a
previous stage.
Change-Id: Ic5906626df09d3801435488e258490765e8f81eb
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
Implements mitigation for CVE-2024-5660 that affects Cortex-X925
revisions r0p0, r0p1.
The workaround is to disable the hardware page aggregation at
EL3 by setting CPUECTLR_EL1[46] = 1'b1.
Public Documentation:
https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-5660
Change-Id: I9d5a07ca6b89b27d8876f4349eff2af26c962d8a
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
Implements mitigation for CVE-2024-5660 that affects Cortex-X2
revisions r0p0, r1p0, r2p0, r2p1.
The workaround is to disable the hardware page aggregation at
EL3 by setting CPUECTLR_EL1[46] = 1'b1
Public Documentation:
https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-5660
Change-Id: If28804e154617a39d7d52c40b3a00a14a39df929
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
Implements mitigation for CVE-2024-5660 that affects Cortex-A77
revisions r0p0, r1p0, r1p1.
The workaround is to disable the hardware page aggregation at
EL3 by setting CPUECTLR_EL1[46] = 1'b1.
Public Documentation:
https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-5660
Change-Id: Ic71b163883ea624e9f2f77deb8b30c69612938b9
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
Implements mitigation for CVE-2024-5660 that affects Neoverse-V1
revisions r0p0, r1p0, r1p1, r1p2.
The workaround is to disable the hardware page aggregation at
EL3 by setting CPUECTLR_EL1[46] = 1'b1.
Public Documentation:
https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-5660
Change-Id: Ia59452ea38c66b291790956d7f2880bfcd56d45f
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
Implements mitigation for CVE-2024-5660 that affects Cortex-A78_AE
revisions r0p0, r0p1, r0p2, r0p3.
The workaround is to disable the hardware page aggregation at
EL3 by setting CPUECTLR_EL1[46] = 1'b1.
Public Documentation:
https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-5660
Change-Id: I33ac653fcb45f687fe9ace1c76a3eb2000459751
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
Implements mitigation for CVE-2024-5660 that affects Cortex-A78C
revisions r0p0, r0p1, r0p2.
The workaround is to disable the hardware page aggregation at
EL3 by setting CPUECTLR_EL1[46] = 1'b1.
Public Documentation:
https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-5660
Change-Id: Ieb8d7b122320d16bf8987a43dc683ca41227beb5
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
Implements mitigation for CVE-2024-5660 that affects Cortex-A78
revisions r0p0, r1p0, r1p1, r1p2.
The workaround is to disable the hardware page aggregation at
EL3 by setting CPUECTLR_EL1[46] = 1'b1.
Public Documentation:
https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-5660
Change-Id: I4e40388bef814481943b2459fe35dd7267c625a2
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
Implements mitigation for CVE-2024-5660 that affects Cortex-X1
revisions r0p0, r1p0, r1p1, r1p2.
The workaround is to disable the hardware page aggregation at
EL3 by setting CPUECTLR_EL1[46] = 1'b1.
Public Documentation:
https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-5660
Change-Id: I3124db3980f2786412369a010ca6abbbbaa3b601
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
Implements mitigation for CVE-2024-5660 that affects Neoverse-N2
revisions r0p0, r0p1, r0p2, r0p3.
The workaround is to disable the hardware page aggregation at
EL3 by setting CPUECTLR_EL1[46] = 1'b1.
This patch implements the erratum mitigation for Neoverse-N2.
Public Documentation:
https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-5660
Change-Id: I2b9dea78771cc159586a03ff563c0ec79591ea64
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
Implements mitigation for CVE-2024-5660 that affects Cortex-A710
revisions r0p0, r1p0, r2p0, r2p1.
The workaround is to disable the hardware page aggregation at
EL3 by setting CPUECTLR_EL1[46] = 1'b1.
Public Documentation:
https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-5660
Change-Id: I10feea238600dcceaac7bb75a59db7913ca65cf1
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
Implements mitigation for CVE-2024-5660 that affects Neoverse-V2
revisions r0p0, r0p1, r0p2.
The workaround is to disable the hardware page aggregation at
EL3 by setting CPUECTLR_EL1[46] = 1'b1.
Public Documentation:
https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-5660
Change-Id: If66687add52d16f68ce54fe5433dd3b3f067ee04
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
Implements mitigation for CVE-2024-5660 that affects Cortex-X3
revisions r0p0, r1p0, r1p1, r1p2.
The workaround is to disable the hardware page aggregation at
EL3 by setting CPUECTLR_EL1[46] = 1'b1.
Public Documentation:
https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-5660
Change-Id: Ibe90313948102ece3469f2cfe3faccc7f4beeabe
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
Implements mitigation for CVE-2024-5660 that affects Neoverse-V3
revisions r0p0, r0p1.
The workaround is to disable the hardware page aggregation at
EL3 by setting CPUECTLR_EL1[46] = 1'b1.
Public Documentation:
https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-5660
Change-Id: I9ed2590bf1215bf6a692f01dfd351e469ff072f8
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
Implements mitigation for CVE-2024-5660 that affects Cortex-X4
revisions r0p0, r0p1, r0p2.
The workaround is to disable the hardware page aggregation at
EL3 by setting CPUECTLR_EL1[46] = 1'b1.
Public Documentation:
https://developer.arm.com/Arm%20Security%20Center/Arm%20CPU%20Vulnerability%20CVE-2024-5660
Change-Id: I378cb4978919cced03e7febc2ad431c572eac72d
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
This patch fixes a bug which was introduced in commit
3065513 related to improper saving of EL1 context in the
context management library code when using 128-bit
system registers.
Bug explanation:
The function el1_sysregs_context_save still used the normal
macros that read all the system registers related to the EL1
context, which then involved casting them to uint64_t and
eventually writing them to a memory structure. This means that
the context management library was saving EL1-related SYSREG128
registers with the upper 64 bits zeroed out.
Alternative macros had previously been introduced for the EL2
context in the aforementioned commit, but not for EL1.
Some refactoring has also been done as part of this patch:
- Re-added "common" back to write_el2_ctx_common_sysreg128
- Added dummy SYSREG128 macros for cases when some features
are disabled
- Removed some newlines
Change-Id: I15aa2190794ac099a493e5f430220b1c81e1b558
Signed-off-by: Igor Podgainõi <igor.podgainoi@arm.com>
Just like for SPE, we need to synchronize TRBE samples before we change
the context to ensure everything goes where it was intended to. If that
is not done, the in-flight entries might use any piece of now incorrect
context as there are no implicit ordering requirements.
Prior to root context, the buffer drain hooks would have done that. But
now that must happen much earlier. So add a tsb to prepare_el3_entry as
well.
Annoyingly, the barrier can be reordered relative to other instructions
by default (rule RCKVWP). So add an isb after the psb/tsb to assure that
they are ordered, at least as far as context is concerned.
Then, drop the buffer draining hooks. Everything they need to do is
already done by now. There's a notable difference in that there are no
dsb-s now. Since EL3 does not access the buffers or the feature
specific context, we don't need to wait for them to finish.
Finally, drop a stray isb in the context saving macro. It is now
absorbed into root context, but was missed.
Change-Id: I30797a40ac7f91d0bb71ad271a1597e85092ccd5
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
In the chapter about FEAT_SPE (D16.4 specifically) it is stated that
"Sampling is always disabled at EL3". That means that disabling sampling
(writing PMBLIMITR_EL1.E to 0) is redundant and can be removed. The only
reason we save/restore SPE context is because of that disable, so those
can be removed too.
There's the issue of draining the profiling buffer though. No new
samples will have been generated since entering EL3. However, old
samples might still be in-flight. Unless synchronised by a psb csync,
those might be affected by our extensive context mutation. Adding a psb
in prepare_el3_entry should cater for that. Note that prior to the
introduction of root context this was not a problem as context remained
unchanged and the hooks took care of the rest.
Then, the only time we care about the buffer actually making it to
memory is when we exit coherency. On HW_ASSISTED_COHERENCY systems we
don't have to do anything, it should be handled for us. Systems without
it need a dsb to wait for them to complete. There should be one already
in each cpu's powerdown hook which should work.
While on the topic of barriers, the esb barrier is no longer used.
Remove it.
Change-Id: I9736fc7d109702c63e7d403dc9e2a4272828afb2
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
This patch enables support of FEAT_FPMR by enabling access
to FPMR register. It achieves it by setting the EnFPM bit of
SCR_EL3. This feature is currently enabled for NS world only.
Reference:
https://developer.arm.com/documentation/109697/2024_09/
Feature-descriptions/The-Armv9-5-architecture-extension?lang=en
Change-Id: I580c409b9b22f8ead0737502280fb9093a3d5dd2
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Cortex-X4 erratum 2923935 is a Cat B erratum that applies
to all revisions <= r0p1 and is fixed in r0p2.
The workaround is to set CPUACTLR4_EL1[11:10] to 0b11.
SDEN documentation:
https://developer.arm.com/documentation/SDEN-2432808/latest
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: I9207802ad479919a7f77c1271019fa2479e076ee
According to Platform Initialization (PI) Specification [1] and
discussion on edk2 mailing list [2],
StandaloneMm shouldn't create Hob but it should be passed from TF-A.
IOW, TF-A should pass boot information via HOB list to initialise
StandaloneMm properly.
And this HOB lists could be delivered via
- SPM_MM: Transfer List according to the firmware handoff spec[3]
- FF-A v1.1 >= : FF-A boot protocol.
This patch introduces a TF-A HOB creation library and
some of definitions which StandaloneMm requires to boot.
Link: https://uefi.org/sites/default/files/resources/PI_Spec_1_6.pdf [1]
Link: https://edk2.groups.io/g/devel/topic/103675962#114283 [2]
Link: https://github.com/FirmwareHandoff/firmware_handoff [3]
Signed-off-by: Levi Yun <yeoreum.yun@arm.com>
Change-Id: I5e0838adce487110206998a8b79bc3adca922cec
