Commit Graph

302 Commits

Author SHA1 Message Date
Mark Dykes f09852c97b Merge changes from topic "sb/dualroot" into integration
* changes:
  plat/arm: Pass cookie argument down to arm_get_rotpk_info()
  plat/arm: Add support for dualroot CoT
  plat/arm: Provide some PROTK files for development
2020-03-10 18:34:56 +00:00
Olivier Deprez d95f7a7287 Merge changes from topic "spmd-sel2" into integration
* changes:
  SPMD: add command line parameter to run SPM at S-EL2 or S-EL1
  SPMD: smc handler qualify secure origin using booleans
  SPMD: SPMC init, SMC handler cosmetic changes
  SPMD: [tegra] rename el1_sys_regs structure to sys_regs
  SPMD: Adds partially supported EL2 registers.
  SPMD: save/restore EL2 system registers.
2020-03-06 08:18:03 +00:00
Max Shvetsov 033039f8e5 SPMD: add command line parameter to run SPM at S-EL2 or S-EL1
Added SPMD_SPM_AT_SEL2 build command line parameter.
Set to 1 to run SPM at S-EL2.
Set to 0 to run SPM at S-EL1 (pre-v8.4 or S-EL2 is disabled).
Removed runtime EL from SPM core manifest.

Change-Id: Icb4f5ea4c800f266880db1d410d63fe27a1171c0
Signed-off-by: Artsem Artsemenka <artsem.artsemenka@arm.com>
Signed-off-by: Max Shvetsov <maksims.svecovs@arm.com>
2020-03-03 11:38:36 +00:00
Manish Pandey 8f066f6167 fvp: add Cactus/Ivy Secure Partition information
Add load address and UUID in fw config dts for Cactus and Ivy which are
example SP's in tf-test repository.

For prototype purpose these information is added manually but later on
it will be updated at compile time from SP layout file and SP manifests
provided by platform.

Change-Id: I41f485e0245d882c7b514bad41fae34036597ce4
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
2020-03-03 11:00:25 +00:00
Manish Pandey 2403813779 Merge changes I75f6d135,I4add470e,I0ecd3a2b,I67a63d73 into integration
* changes:
  board/rddaniel: intialize tzc400 controllers
  plat/arm/tzc: add support to configure multiple tzc400
  plat/arm: allow boards to specify second DRAM Base address
  plat/arm: allow boards to define PLAT_ARM_TZC_FILTERS
2020-02-28 16:52:55 +00:00
Olivier Deprez 8b29a0f655 Merge "FVP: Fix incorrect GIC mapping" into integration 2020-02-26 09:52:31 +00:00
Alexei Fedorov b3c431f35b FVP: Fix incorrect GIC mapping
This patch fixes incorrect setting for DEVICE1_SIZE
for FVP platforms with more than 8 PEs.
The current value of 0x200000 supports only 8 PEs
and causes exception for FVP platforms with the greater
number of PEs, e.g. FVP_Base_Cortex_A65AEx8 with 16 PEs
in one cluster.

Change-Id: Ie6391509fe6eeafb8ba779303636cd762e7d21b2
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>
2020-02-25 17:03:34 +00:00
Petre-Ionut Tudor 60e8f3cfd5 Read-only xlat tables for BL31 memory
This patch introduces a build flag which allows the xlat tables
to be mapped in a read-only region within BL31 memory. It makes it
much harder for someone who has acquired the ability to write to
arbitrary secure memory addresses to gain control of the
translation tables.

The memory attributes of the descriptors describing the tables
themselves are changed to read-only secure data. This change
happens at the end of BL31 runtime setup. Until this point, the
tables have read-write permissions. This gives a window of
opportunity for changes to be made to the tables with the MMU on
(e.g. reclaiming init code). No changes can be made to the tables
with the MMU turned on from this point onwards. This change is also
enabled for sp_min and tspd.

To make all this possible, the base table was moved to .rodata. The
penalty we pay is that now .rodata must be aligned to the size of
the base table (512B alignment). Still, this is better than putting
the base table with the higher level tables in the xlat_table
section, as that would cost us a full 4KB page.

Changing the tables from read-write to read-only cannot be done with
the MMU on, as the break-before-make sequence would invalidate the
descriptor which resolves the level 3 page table where that very
descriptor is located. This would make the translation required for
writing the changes impossible, generating an MMU fault.

The caches are also flushed.

Signed-off-by: Petre-Ionut Tudor <petre-ionut.tudor@arm.com>
Change-Id: Ibe5de307e6dc94c67d6186139ac3973516430466
2020-02-24 16:52:56 +00:00
Sandrine Bailleux 88005701ec plat/arm: Pass cookie argument down to arm_get_rotpk_info()
The cookie will be leveraged in the next commit.

Change-Id: Ie8bad275d856d84c27466461cf815529dd860446
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
2020-02-24 11:01:46 +01:00
joanna.farley 2f39c55c08 Merge "Add Matterhorn CPU lib" into integration 2020-02-21 17:51:10 +00:00
joanna.farley e571211392 Merge "Add CPULib for Klein Core" into integration 2020-02-21 17:50:01 +00:00
Suyash Pathak 4ed1676518 plat/arm/tzc: add support to configure multiple tzc400
For platforms that have two or more TZC400 controllers instantiated,
allow the TZC400 driver to be usable with all those instances.
This is achieved by allowing 'arm_tzc400_setup' function to accept
the base address of the TZC400 controller.

Change-Id: I4add470e6ddb58432cd066145e644112400ab924
Signed-off-by: Suyash Pathak <suyash.pathak@arm.com>
2020-02-19 13:26:53 +05:30
Jimmy Brisson da3b47e925 Add Matterhorn CPU lib
Also update copyright statements

Change-Id: Iba0305522ac0f2ddc4da99127fd773f340e67300
Signed-off-by: Jimmy Brisson <jimmy.brisson@arm.com>
2020-02-18 09:00:04 -06:00
Jimmy Brisson f4744720a0 Add CPULib for Klein Core
Change-Id: I686fd623b8264c85434853a2a26ecd71e9eeac01
Signed-off-by: Jimmy Brisson <jimmy.brisson@arm.com>
2020-02-18 08:57:32 -06:00
Alexei Fedorov 6227cca9e8 FVP: Fix BL31 load address and image size for RESET_TO_BL31=1
When TF-A is built with RESET_TO_BL31=1 option, BL31 is the
first image to be run and should have all the memory allocated
to it except for the memory reserved for Shared RAM at the start
of Trusted SRAM.
This patch fixes FVP BL31 load address and its image size for
RESET_TO_BL31=1 option. BL31 startup address should be set to
0x400_1000 and its maximum image size to the size of Trusted SRAM
minus the first 4KB of shared memory.
Loading BL31 at 0x0402_0000 as it is currently stated in
'\docs\plat\arm\fvp\index.rst' causes EL3 exception when the
image size gets increased (i.e. building with LOG_LEVEL=50)
but doesn't exceed 0x3B000 not causing build error.

Change-Id: Ie450baaf247f1577112f8d143b24e76c39d33e91
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>
2020-02-18 10:16:51 +00:00
Sandrine Bailleux 21c4f56fa7 Merge changes from topic "lm/fconf" into integration
* changes:
  arm-io: Panic in case of io setup failure
  MISRA fix: Use boolean essential type
  fconf: Add documentation
  fconf: Move platform io policies into fconf
  fconf: Add mbedtls shared heap as property
  fconf: Add TBBR disable_authentication property
  fconf: Add dynamic config DTBs info as property
  fconf: Populate properties from dtb during bl2 setup
  fconf: Load config dtb from bl1
  fconf: initial commit
2020-02-11 16:15:45 +00:00
Olivier Deprez 63aa4094fb Merge changes from topic "spmd" into integration
* changes:
  SPMD: enable SPM dispatcher support
  SPMD: hook SPMD into standard services framework
  SPMD: add SPM dispatcher based upon SPCI Beta 0 spec
  SPMD: add support to run BL32 in TDRAM and BL31 in secure DRAM on Arm FVP
  SPMD: add support for an example SPM core manifest
  SPMD: add SPCI Beta 0 specification header file
2020-02-11 08:34:47 +00:00
Manish Pandey ea25ce90ec Merge "fvp: Slightly Bump the stack size for bl1 and bl2" into integration 2020-02-10 16:56:11 +00:00
Achin Gupta 64758c97ee SPMD: add support to run BL32 in TDRAM and BL31 in secure DRAM on Arm FVP
This patch reserves and maps the Trusted DRAM for SPM core execution.
It also configures the TrustZone address space controller to run BL31
in secure DRAM.

Signed-off-by: Achin Gupta <achin.gupta@arm.com>
Signed-off-by: Artsem Artsemenka <artsem.artsemenka@arm.com>
Change-Id: I7e1bb3bbc61a0fec6a9cb595964ff553620c21dc
2020-02-10 14:09:21 +00:00
Achin Gupta 0cb64d01d9 SPMD: add support for an example SPM core manifest
This patch repurposes the TOS FW configuration file as the manifest for
the SPM core component which will reside at the secure EL adjacent to
EL3. The SPM dispatcher component will use the manifest to determine how
the core component must be initialised. Routines and data structure to
parse the manifest have also been added.

Signed-off-by: Achin Gupta <achin.gupta@arm.com>
Signed-off-by: Artsem Artsemenka <artsem.artsemenka@arm.com>
Change-Id: Id94f8ece43b4e05609f0a1d364708a912f6203cb
2020-02-10 14:09:10 +00:00
Louis Mayencourt 9739982125 arm-io: Panic in case of io setup failure
Currently, an IO setup failure will be ignored on arm platform release
build. Change this to panic instead.

Change-Id: I027a045bce2422b0a0fc4ff9e9d4c6e7bf5d2f98
Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>
2020-02-07 13:51:32 +00:00
Louis Mayencourt 0a6e7e3b76 fconf: Move platform io policies into fconf
Use the firmware configuration framework to store the io_policies
information inside the configuration device tree instead of the static
structure in the code base.

The io_policies required by BL1 can't be inside the dtb, as this one is
loaded by BL1, and only available at BL2.

This change currently only applies to FVP platform.

Change-Id: Ic9c1ac3931a4a136aa36f7f58f66d3764c1bfca1
Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>
2020-02-07 13:51:32 +00:00
Louis Mayencourt 25ac87940c fconf: Add dynamic config DTBs info as property
This patch introduces a better separation between the trusted-boot
related properties, and the dynamic configuration DTBs loading
information.

The dynamic configuration DTBs properties are moved to a new node:
`dtb-registry`. All the sub-nodes present will be provided to the
dynamic config framework to be loaded. The node currently only contains
the already defined configuration DTBs, but can be extended for future
features if necessary.
The dynamic config framework is modified to use the abstraction provided
by the fconf framework, instead of directly accessing the DTBs.

The trusted-boot properties are kept under the "arm,tb_fw" compatible
string, but in a separate `tb_fw-config` node.
The `tb_fw-config` property of the `dtb-registry` node simply points
to the load address of `fw_config`, as the `tb_fw-config` is currently
part of the same DTB.

Change-Id: Iceb6c4c2cb92b692b6e28dbdc9fb060f1c46de82
Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>
2020-02-07 13:51:32 +00:00
Max Shvetsov a6ffddec33 Adds option to read ROTPK from registers for FVP
Enables usage of ARM_ROTPK_LOCATION=regs for FVP board.
Removes hard-coded developer keys. Instead, setting
ARM_ROTPK_LOCATION=devel_* takes keys from default directory.
In case of ROT_KEY specified - generates a new hash and replaces the
original.

Note: Juno board was tested by original feature author and was not tested
for this patch since we don't have access to the private key. Juno
implementation was moved to board-specific file without changing
functionality. It is not known whether byte-swapping is still needed
for this platform.

Change-Id: I0fdbaca0415cdcd78f3a388551c2e478c01ed986
Signed-off-by: Max Shvetsov <maksims.svecovs@arm.com>
2020-02-06 16:58:53 +00:00
Louis Mayencourt 64271c7405 fvp: Slightly Bump the stack size for bl1 and bl2
Stack usage reaches 90% with some configuration. Bump slightly the stack
size to prevent a stack-overflow.

Change-Id: I44ce8b12906586a42f152b7677785fcdc5e78ae1
Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>
2020-02-06 16:54:27 +00:00
Mark Dykes 235c8174ff Merge "Coverity: remove unnecessary header file includes" into integration 2020-02-04 17:15:57 +00:00
Zelalem e6937287e4 Coverity: remove unnecessary header file includes
This patch removes unnecessary header file includes
discovered by Coverity HFA option.

Change-Id: I2827c37c1c24866c87db0e206e681900545925d4
Signed-off-by: Zelalem <zelalem.aweke@arm.com>
2020-02-04 10:23:51 -06:00
Alexei Fedorov 0a2ab6e635 FDT wrappers: add functions for read/write bytes
This patch adds 'fdtw_read_bytes' and 'fdtw_write_inplace_bytes'
functions for read/write array of bytes from/to a given property.
It also adds 'fdt_setprop_inplace_namelen_partial' to jmptbl.i
files for builds with USE_ROMLIB=1 option.

Change-Id: Ied7b5c8b38a0e21d508aa7bcf5893e656028b14d
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>
2020-02-03 11:41:27 +00:00
Mark Dykes 436367966f Merge "Unify type of "cpu_idx" across PSCI module." into integration 2020-01-10 19:39:17 +00:00
Deepika Bhavnani 5b33ad174a Unify type of "cpu_idx" across PSCI module.
NOTE for platform integrators:
   API `plat_psci_stat_get_residency()` third argument
   `last_cpu_idx` is changed from "signed int" to the
   "unsigned int" type.

Issue / Trouble points
1. cpu_idx is used as mix of `unsigned int` and `signed int` in code
with typecasting at some places leading to coverity issues.

2. Underlying platform API's return cpu_idx as `unsigned int`
and comparison is performed with platform specific defines
`PLAFORM_xxx` which is not consistent

Misra Rule 10.4:
The value of a complex expression of integer type may only be cast to
a type that is narrower and of the same signedness as the underlying
type of the expression.

Based on above points, cpu_idx is kept as `unsigned int` to match
the API's and low-level functions and platform defines are updated
where ever required

Signed-off-by: Deepika Bhavnani <deepika.bhavnani@arm.com>
Change-Id: Ib26fd16e420c35527204b126b9b91e8babcc3a5c
2020-01-10 17:11:51 +00:00
Mark Dykes 5c33096742 Merge "FVP: Remove re-definition of topology related build options" into integration 2020-01-10 16:42:27 +00:00
Alexei Fedorov 94f1c9593d FVP: Remove re-definition of topology related build options
This patch removes re-definition of the following FVP build
options from plat\arm\board\fvp\fvp_def.h:
 'FVP_CLUSTER_COUNT'
 'FVP_MAX_CPUS_PER_CLUSTER'
 'FVP_MAX_PE_PER_CPU'
which are set in platform.mk.

This fixes a potential problem when a build option set in
platform.mk file can be re-defined in fvp_def.h header file
used by other build component with a different makefile which
does not set this option.
Ref. GENFW-3505.

Change-Id: I4288629920516acf2c239c7b733f92a0c5a812ff
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>
2020-01-10 14:24:17 +00:00
Ambroise Vincent a6ffd375c7 FVP: Stop reclaiming init code with Clang builds
The reclaim init code functionality relies on forward reference in the
linker script. The LLVM linker does not process it correctly.

Change-Id: I993aeb9587bfa07af25b60ed823a6a2c5e970c94
Signed-off-by: Ambroise Vincent <ambroise.vincent@arm.com>
Signed-off-by: Zelalem Aweke <zelalem.aweke@arm.com>
2020-01-07 10:14:37 -06:00
Mark Dykes 86ed8953b5 Merge "debugfs: add SMC channel" into integration 2019-12-20 20:56:23 +00:00
Paul Beesley aeaa225cbe spm-mm: Refactor secure_partition.h and its contents
Before adding any new SPM-related components we should first do
some cleanup around the existing SPM-MM implementation. The aim
is to make sure that any SPM-MM components have names that clearly
indicate that they are MM-related. Otherwise, when adding new SPM
code, it could quickly become confusing as it would be unclear to
which component the code belongs.

The secure_partition.h header is a clear example of this, as the
name is generic so it could easily apply to any SPM-related code,
when it is in fact SPM-MM specific.

This patch renames the file and the two structures defined within
it, and then modifies any references in files that use the header.

Change-Id: I44bd95fab774c358178b3e81262a16da500fda26
Signed-off-by: Paul Beesley <paul.beesley@arm.com>
2019-12-20 16:03:41 +00:00
Paul Beesley 538b002046 spm: Remove SPM Alpha 1 prototype and support files
The Secure Partition Manager (SPM) prototype implementation is
being removed. This is preparatory work for putting in place a
dispatcher component that, in turn, enables partition managers
at S-EL2 / S-EL1.

This patch removes:

- The core service files (std_svc/spm)
- The Resource Descriptor headers (include/services)
- SPRT protocol support and service definitions
- SPCI protocol support and service definitions

Change-Id: Iaade6f6422eaf9a71187b1e2a4dffd7fb8766426
Signed-off-by: Paul Beesley <paul.beesley@arm.com>
Signed-off-by: Artsem Artsemenka <artsem.artsemenka@arm.com>
2019-12-20 16:03:32 +00:00
Paul Beesley 3f3c341ae5 Remove dependency between SPM_MM and ENABLE_SPM build flags
There are two different implementations of Secure Partition
management in TF-A. One is based on the "Management Mode" (MM)
design, the other is based on the Secure Partition Client Interface
(SPCI) specification. Currently there is a dependency between their
build flags that shouldn't exist, making further development
harder than it should be. This patch removes that
dependency, making the two flags function independently.

Before: ENABLE_SPM=1 is required for using either implementation.
        By default, the SPCI-based implementation is enabled and
        this is overridden if SPM_MM=1.

After: ENABLE_SPM=1 enables the SPCI-based implementation.
       SPM_MM=1 enables the MM-based implementation.
       The two build flags are mutually exclusive.

Note that the name of the ENABLE_SPM flag remains a bit
ambiguous - this will be improved in a subsequent patch. For this
patch the intention was to leave the name as-is so that it is
easier to track the changes that were made.

Change-Id: I8e64ee545d811c7000f27e8dc8ebb977d670608a
Signed-off-by: Paul Beesley <paul.beesley@arm.com>
2019-12-20 16:03:02 +00:00
Ambroise Vincent 992f091b5d debugfs: add SMC channel
Provide an SMC interface to the 9p filesystem. This permits
accessing firmware drivers through a common interface, using
standardized read/write/control operations.

Signed-off-by: Ambroise Vincent <ambroise.vincent@arm.com>
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: I9314662314bb060f6bc02714476574da158b2a7d
2019-12-18 09:59:12 +01:00
Ambroise Vincent a71c59d5cb arm: Fix current RECLAIM_INIT_CODE behavior
Previously the .init section was created even when the reclaim flag was
manually set to 0.

Change-Id: Ia9e7c7997261f54a4eca725d7ea605192f60bcf8
Signed-off-by: Ambroise Vincent <ambroise.vincent@arm.com>
	       Zelalem Aweke <zelalem.aweke@arm.com>
2019-12-09 11:09:09 -06:00
Alexei Fedorov 0ff3fb32f4 Merge "Fix multithreaded FVP power domain tree" into integration 2019-11-20 10:42:47 +00:00
Sandrine Bailleux 896add4f1d Merge changes from topic "lm/improve_memory_layout" into integration
* changes:
  DOC: Update ROMLIB page with memory impact info
  ROMLIB: Optimize memory layout when ROMLIB is used
2019-11-18 16:45:03 +00:00
Louis Mayencourt e7b390892d ROMLIB: Optimize memory layout when ROMLIB is used
ROMLIB extract functions code from BL images to put them inside ROM.
This has for effect to reduce the size of the BL images.

This patch take this size reduction into consideration to optimize the
memory layout of BL2.
A new "PLAT_ARM_BL2_ROMLIB_OPTIMIZATION" macro is defined and used to
reduce "PLAT_ARM_MAX_BL2_SIZE". This allows to remove the gap between
BL1 and BL2 when ROMLIB is used and provides more room for BL31.

The current memory gain is 0x6000 for fvp and 0x8000 for juno.

Change-Id: I71c2c2c63b57bce5b22a125efaefc486ff3e87be
Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>
2019-11-18 13:24:47 +00:00
Imre Kis e2b6a9ced9 Fix multithreaded FVP power domain tree
The number of levels in the topology has not changed but the count of
processing elements on the lowest layer is now multiplied by the value
of FVP_MAX_PE_PER_CPU.

Signed-off-by: Imre Kis <imre.kis@arm.com>
Change-Id: Ia1568a40ea33dbbbcdfab6c8ab6d19f4db0b8eb4
2019-11-15 09:50:06 +00:00
Manish Pandey 133a5c6802 plat/arm: Re-enable PIE when RESET_TO_BL31=1
Earlier PIE support was enabled for all arm platforms when
RESET_TO_BL31=1, but later on it was restricted only to FVP with patch
SHA d4580d17 because of n1sdp platform.

Now it has been verified that PIE does work for n1sdp platform also, so
enabling it again for all arm platforms.

Change-Id: I05ad4f1775ef72e7cb578ec9245cde3fbce971a5
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
2019-11-07 10:23:15 +00:00
Imre Kis 78f02ae296 Introducing support for Cortex-A65AE
Change-Id: I1ea2bf088f1e001cdbd377cbfb7c6a2866af0422
Signed-off-by: Imre Kis <imre.kis@arm.com>
2019-10-03 15:38:31 +02:00
Imre Kis 6ad216dca5 Introducing support for Cortex-A65
Change-Id: I645442d52a295706948e2cac88c36c1a3cb0bc47
Signed-off-by: Imre Kis <imre.kis@arm.com>
2019-10-02 18:12:28 +02:00
Artsem Artsemenka a4668c36f1 Cortex_hercules: Add support for Hercules-AE
Not tested on FVP Model.

Change-Id: Iedebc5c1fbc7ea577e94142b7feafa5546f1f4f9
Signed-off-by: Artsem Artsemenka <artsem.artsemenka@arm.com>
2019-09-30 12:55:31 +01:00
Soby Mathew 41bda86330 Merge changes from topic "mp/giv3-discovery" into integration
* changes:
  Migrate ARM platforms to use the new GICv3 API
  Adding new optional PSCI hook pwr_domain_on_finish_late
  GICv3: Enable multi socket GIC redistributor frame discovery
2019-09-27 09:42:37 +00:00
Madhukar Pappireddy 6806cd2381 Migrate ARM platforms to use the new GICv3 API
This patch invokes the new function gicv3_rdistif_probe() in the
ARM platform specific gicv3 driver. Since this API modifies the
shared GIC related data structure, it must be invoked coherently
by using the platform specific pwr_domain_on_finish_late hook.

Change-Id: I6efb17d5da61545a1c5a6641b8f58472b31e62a8
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
2019-09-25 22:06:49 -05:00
Sandrine Bailleux bd363d356f FVP: Fix plat_set_nv_ctr() function
The Fast Models provide a non-volatile counter component, which is used
in the Trusted Board Boot implementation to protect against rollback
attacks.

This component comes in 2 versions (see [1]).

- Version 0 is the default and models a locked non-volatile counter,
  whose value is fixed.

- Version 1 of the counter may be incremented in a monotonic fashion.

plat_set_nv_ctr() must cope with both versions. This is achieved by:
1) Attempting to write the new value in the counter.
2) Reading the value back.
3) If there is a mismatch, we know the counter upgrade failed.

When using version 0 of the counter, no upgrade is possible so the
function is expected to fail all the time. However, the code is
missing a compiler barrier between the write operation and the next
read. Thus, the compiler may optimize and remove the read operation on
the basis that the counter value has not changed. With the default
optimization level used in TF-A (-Os), this is what's happening.

The fix introduced in this patch marks the write and subsequent read
accesses to the counter as volatile, such that the compiler makes no
assumption about the value of the counter.

Note that the comment above plat_set_nv_ctr() was clearly stating
that when using the read-only version of the non-volatile counter,
"we expect the values in the certificates to always match the RO
values so that this function is never called". However, the fact that
the counter value was read back seems to contradict this comment, as
it is implementing a counter-measure against misuse of the
function. The comment has been reworded to avoid any confusion.

Without this patch, this bug may be demonstrated on the Base AEM FVP:
- Using version 0 of the non-volatile counter (default version).
- With certificates embedding a revision number value of 32
  (compiling TF-A with TFW_NVCTR_VAL=32).

In this configuration, the non-volatile counter is tied to value 31 by
default. When BL1 loads the Trusted Boot Firmware certificate, it
notices that the two values do not match and tries to upgrade the
non-volatile counter. This write operation is expected to fail
(because the counter is locked) and the function is expected to return
an error but it succeeds instead.

As a result, the trusted boot does not abort as soon as it should and
incorrectly boots BL2. The boot is finally aborted when BL2 verifies
the BL31 image and figures out that the version of the SoC Firmware
Key Certificate does not match. On Arm platforms, only certificates
signed with the Root-of-Trust Key may trigger an upgrade of the
non-volatile Trusted counter.

[1] https://developer.arm.com/docs/100964/1160/fast-models-components/peripheral-components/nonvolatilecounter

Change-Id: I9979f29c23b47b338b9b484013d1fb86c59db92f
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
2019-09-25 09:33:40 +02:00