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As per latest mailing communication [1], we decided to
update AT speculative workaround implementation in order to
disable page table walk for lower ELs(EL1 or EL0) immediately
after context switching to EL3 from lower ELs.

Previous implementation of AT speculative workaround is available
here: 45aecff0

AT speculative workaround is updated as below:
1. Avoid saving and restoring of SCTLR and TCR registers for EL1
   in context save and restore routine respectively.
2. On EL3 entry, save SCTLR and TCR registers for EL1.
3. On EL3 entry, update EL1 system registers to disable stage 1
   page table walk for lower ELs (EL1 and EL0) and enable EL1
   MMU.
4. On EL3 exit, restore SCTLR and TCR registers for EL1 which
   are saved in step 2.

[1]:
https://lists.trustedfirmware.org/pipermail/tf-a/2020-July/000586.html



Change-Id: Iee8de16f81dc970a8f492726f2ddd57e7bd9ffb5
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>

SCTLR and TCR registers of EL1 plays role in enabling/disabling of
page table walk for lower ELs (EL0 and EL1).
Hence re-arranged EL1 context offsets to have SCTLR and TCR registers
values one after another in the stack so that these registers values
can be saved and restored using stp and ldp instruction respectively.

Change-Id: Iaa28fd9eba82a60932b6b6d85ec8857a9acd5f8b
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>

As per latest mailing communication [1], we decided
not to update SCTLR and TCR registers in EL1 and EL2 context
restore routine when AT speculative workaround is enabled
hence reverted the changes done as part of this commit: 45aecff0.

[1]:
https://lists.trustedfirmware.org/pipermail/tf-a/2020-July/000586.html



Change-Id: I8c5f31d81fcd53770a610e302a5005d98772b71f
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>

Removing FPEXC32_EL2 from the register save/restore routine for EL2
registers since it is already a part of save/restore routine for
fpregs.
Signed-off-by: Max Shvetsov <maksims.svecovs@arm.com>
Change-Id: I5ed45fdbf7c8efa8dcfcd96586328d4f6b256bc4

During context switching from higher EL (EL2 or higher)
to lower EL can cause incorrect translation in TLB due to
speculative execution of AT instruction using out-of-context
translation regime.

Workaround is implemented as below during EL's (EL1 or EL2)
"context_restore" operation:
1. Disable page table walk using SCTLR.M and TCR.EPD0 & EPD1
   bits for EL1 or EL2 (stage1 and stage2 disabled)
2. Save all system registers except TCR and SCTLR (for EL1 and EL2)
3. Do memory barrier operation (isb) to ensure all
   system register writes are done.
4. Restore TCR and SCTLR registers (for EL1 and EL2)

Errata details are available for various CPUs as below:
Cortex-A76: 1165522
Cortex-A72: 1319367
Cortex-A57: 1319537
Cortex-A55: 1530923
Cortex-A53: 1530924

More details can be found in mail-chain:
https://lists.trustedfirmware.org/pipermail/tf-a/2020-April/000445.html



Currently, Workaround is implemented as build option which is default
disabled.
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
Change-Id: If8545e61f782cb0c2dda7ffbaf50681c825bd2f0

TPIDR_EL2 is missing from the EL2 state register save/restore
sequence. This patch adds it to the context save restore routines.
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: I35fc5ee82f97b72bcedac57c791312e7b3a45251

This patch adds EL2 registers that are supported up to ARMv8.6.
ARM_ARCH_MINOR has to specified to enable save/restore routine.

Note: Following registers are still not covered in save/restore.
 * AMEVCNTVOFF0<n>_EL2
 * AMEVCNTVOFF1<n>_EL2
 * ICH_AP0R<n>_EL2
 * ICH_AP1R<n>_EL2
 * ICH_LR<n>_EL2

Change-Id: I4813f3243e56e21cb297b31ef549a4b38d4876e1
Signed-off-by: Max Shvetsov <maksims.svecovs@arm.com>

NOTE: Not all EL-2 system registers are saved/restored.
This subset includes registers recognized by ARMv8.0

Change-Id: I9993c7d78d8f5f8e72d1c6c8d6fd871283aa3ce0
Signed-off-by: Jose Marinho <jose.marinho@arm.com>
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Signed-off-by: Artsem Artsemenka <artsem.artsemenka@arm.com>
Signed-off-by: Max Shvetsov <maksims.svecovs@arm.com>

Even though ERET always causes a jump to another address, aarch64 CPUs
speculatively execute following instructions as if the ERET
instruction was not a jump instruction.
The speculative execution does not cross privilege-levels (to the jump
target as one would expect), but it continues on the kernel privilege
level as if the ERET instruction did not change the control flow -
thus execution anything that is accidentally linked after the ERET
instruction. Later, the results of this speculative execution are
always architecturally discarded, however they can leak data using
microarchitectural side channels. This speculative execution is very
reliable (seems to be unconditional) and it manages to complete even
relatively performance-heavy operations (e.g. multiple dependent
fetches from uncached memory).

This was fixed in Linux, FreeBSD, OpenBSD and Optee OS:
https://github.com/torvalds/linux/commit/679db70801da9fda91d26caf13bf5b5ccc74e8e8
https://github.com/freebsd/freebsd/commit/29fb48ace4186a41c409fde52bcf4216e9e50b61
https://github.com/openbsd/src/commit/3a08873ece1cb28ace89fd65e8f3c1375cc98de2
https://github.com/OP-TEE/optee_os/commit/abfd092aa19f9c0251e3d5551e2d68a9ebcfec8a

It is demonstrated in a SafeSide example:
https://github.com/google/safeside/blob/master/demos/eret_hvc_smc_wrapper.cc
https://github.com/google/safeside/blob/master/kernel_modules/kmod_eret_hvc_smc/eret_hvc_smc_module.c

Signed-off-by: Anthony Steinhauser <asteinhauser@google.com>
Change-Id: Iead39b0b9fb4b8d8b5609daaa8be81497ba63a0f

EA handlers for exceptions taken from lower ELs at the end invokes
el3_exit function. However there was a bug with sp maintenance which
resulted in el3_exit setting runtime stack to context. This in turn
caused memory corruption on consecutive EL3 entries.
Signed-off-by: Jan Dabros <jsd@semihalf.com>
Change-Id: I0424245c27c369c864506f4baa719968890ce659

This patch provides the following features and makes modifications
listed below:
- Individual APIAKey key generation for each CPU.
- New key generation on every BL31 warm boot and TSP CPU On event.
- Per-CPU storage of APIAKey added in percpu_data[]
  of cpu_data structure.
- `plat_init_apiakey()` function replaced with `plat_init_apkey()`
  which returns 128-bit value and uses Generic timer physical counter
  value to increase the randomness of the generated key.
  The new function can be used for generation of all ARMv8.3-PAuth keys
- ARMv8.3-PAuth specific code placed in `lib\extensions\pauth`.
- New `pauth_init_enable_el1()` and `pauth_init_enable_el3()` functions
  generate, program and enable APIAKey_EL1 for EL1 and EL3 respectively;
  pauth_disable_el1()` and `pauth_disable_el3()` functions disable
  PAuth for EL1 and EL3 respectively;
  `pauth_load_bl31_apiakey()` loads saved per-CPU APIAKey_EL1 from
  cpu-data structure.
- Combined `save_gp_pauth_registers()` function replaces calls to
  `save_gp_registers()` and `pauth_context_save()`;
  `restore_gp_pauth_registers()` replaces `pauth_context_restore()`
  and `restore_gp_registers()` calls.
- `restore_gp_registers_eret()` function removed with corresponding
  code placed in `el3_exit()`.
- Fixed the issue when `pauth_t pauth_ctx` structure allocated space
  for 12 uint64_t PAuth registers instead of 10 by removal of macro
  CTX_PACGAKEY_END from `include/lib/el3_runtime/aarch64/context.h`
  and assigning its value to CTX_PAUTH_REGS_END.
- Use of MODE_SP_ELX and MODE_SP_EL0 macro definitions
  in `msr	spsel`  instruction instead of hard-coded values.
- Changes in documentation related to ARMv8.3-PAuth and ARMv8.5-BTI.

Change-Id: Id18b81cc46f52a783a7e6a09b9f149b6ce803211
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>

This patch adds support for the new Memory Tagging Extension arriving in
ARMv8.5. MTE support is now enabled by default on systems that support
at EL0. To enable it at ELx for both the non-secure and the secure
world, the compiler flag CTX_INCLUDE_MTE_REGS includes register saving
and restoring when necessary in order to prevent register leakage
between the worlds.

Change-Id: I2d4ea993d6b11654ea0d4757d00ca20d23acf36c
Signed-off-by: Justin Chadwell <justin.chadwell@arm.com>

This patch fixes an issue when secure world timing information
can be leaked because Secure Cycle Counter is not disabled.
For ARMv8.5 the counter gets disabled by setting MDCR_El3.SCCD
bit on CPU cold/warm boot.
For the earlier architectures PMCR_EL0 register is saved/restored
on secure world entry/exit from/to Non-secure state, and cycle
counting gets disabled by setting PMCR_EL0.DP bit.
'include\aarch64\arch.h' header file was tided up and new
ARMv8.5-PMU related definitions were added.

Change-Id: I6f56db6bc77504634a352388990ad925a69ebbfa
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>

Instruction key A was incorrectly restored in the instruction key B
registers.

Change-Id: I4cb81ac72180442c077898509cb696c9d992eda3
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>

Fix some typos and clarify some sentences.

Change-Id: Id276d1ced9a991b4eddc5c47ad9a825e6b29ef74
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

The previous commit added the infrastructure to load and save
ARMv8.3-PAuth registers during Non-secure <-> Secure world switches, but
didn't actually enable pointer authentication in the firmware.

This patch adds the functionality needed for platforms to provide
authentication keys for the firmware, and a new option (ENABLE_PAUTH) to
enable pointer authentication in the firmware itself. This option is
disabled by default, and it requires CTX_INCLUDE_PAUTH_REGS to be
enabled.

Change-Id: I35127ec271e1198d43209044de39fa712ef202a5
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

ARMv8.3-PAuth adds functionality that supports address authentication of
the contents of a register before that register is used as the target of
an indirect branch, or as a load.

This feature is supported only in AArch64 state.

This feature is mandatory in ARMv8.3 implementations.

This feature adds several registers to EL1. A new option called
CTX_INCLUDE_PAUTH_REGS has been added to select if the TF needs to save
them during Non-secure <-> Secure world switches. This option must be
enabled if the hardware has the registers or the values will be leaked
during world switches.

To prevent leaks, this patch also disables pointer authentication in the
Secure world if CTX_INCLUDE_PAUTH_REGS is 0. Any attempt to use it will
be trapped in EL3.

Change-Id: I27beba9907b9a86c6df1d0c5bf6180c972830855
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

Minor style cleanup.

Change-Id: Ief19dece41a989e2e8157859a265701549f6c585
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

Some CPUS may benefit from using a dynamic mitigation approach for
CVE-2018-3639.  A new SMC interface is defined to allow software
executing in lower ELs to enable or disable the mitigation for their
execution context.

It should be noted that regardless of the state of the mitigation for
lower ELs, code executing in EL3 is always mitigated against
CVE-2018-3639.

NOTE: This change is a compatibility break for any platform using
the declare_cpu_ops_workaround_cve_2017_5715 macro.  Migrate to
the declare_cpu_ops_wa macro instead.

Change-Id: I3509a9337ad217bbd96de9f380c4ff8bf7917013
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

RAS extensions are mandatory for ARMv8.2 CPUs, but are also optional
extensions to base ARMv8.0 architecture.

This patch adds build system support to enable RAS features in ARM
Trusted Firmware. A boolean build option RAS_EXTENSION is introduced for
this.

With RAS_EXTENSION, an Exception Synchronization Barrier (ESB) is
inserted at all EL3 vector entry and exit. ESBs will synchronize pending
external aborts before entering EL3, and therefore will contain and
attribute errors to lower EL execution. Any errors thus synchronized are
detected via. DISR_EL1 register.

When RAS_EXTENSION is set to 1, HANDLE_EL3_EA_FIRST must also be set to 1.

Change-Id: I38a19d84014d4d8af688bd81d61ba582c039383a
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>

At present, the function that restores general purpose registers also
does ERET. Refactor the restore code to restore general purpose
registers without ERET to complement the save function.

The macro save_x18_to_x29_sp_el0 was used only once, and is therefore
removed, and its contents expanded inline for readability.

No functional changes, but with this patch:

  - The SMC return path will incur an branch-return and an additional
    register load.

  - The unknown SMC path restores registers x0 to x3.

Change-Id: I7a1a63e17f34f9cde810685d70a0ad13ca3b7c50
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>

Factor out SPE operations in a separate file.  Use the publish
subscribe framework to drain the SPE buffers before entering secure
world.  Additionally, enable SPE before entering normal world.

A side effect of this change is that the profiling buffers are now
only drained when a transition from normal world to secure world
happens.  Previously they were drained also on return from secure
world, which is unnecessary as SPE is not supported in S-EL1.

Change-Id: I17582c689b4b525770dbb6db098b3a0b5777b70a
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

The FPEXC32_EL2 register controls SIMD and FP functionality when the
lower ELs are executing in AArch32 mode. It is architecturally mapped
to AArch32 system register FPEXC.

This patch removes FPEXC32_EL2 register from the System Register context
and adds it to the floating-point context. EL3 only saves / restores the
floating-point context if the build option CTX_INCLUDE_FPREGS is set to 1.

The rationale for this change is that if the Secure world is using FP
functionality and EL3 is not managing the FP context, then the Secure
world will save / restore the appropriate FP registers.

NOTE - this is a break in behaviour in the unlikely case that
CTX_INCLUDE_FPREGS is set to 0 and the platform contains an AArch32
Secure Payload that modifies FPEXC, but does not save and restore
this register

Change-Id: Iab80abcbfe302752d52b323b4abcc334b585c184
Signed-off-by: David Cunado <david.cunado@arm.com>

Currently TF does not initialise the PMCR_EL0 register in
the secure context or save/restore the register.

In particular, the DP field may not be set to one to prohibit
cycle counting in the secure state, even though event counting
generally is prohibited via the default setting of MDCR_EL3.SMPE
to 0.

This patch initialises PMCR_EL0.DP to one in the secure state
to prohibit cycle counting and also initialises other fields
that have an architectually UNKNOWN reset value.

Additionally, PMCR_EL0 is added to the list of registers that are
saved and restored during a world switch.

Similar changes are made for PMCR for the AArch32 execution state.

NOTE: secure world code at lower ELs that assume other values in PMCR_EL0
will be impacted.

Change-Id: Iae40e8c0a196d74053accf97063ebc257b4d2f3a
Signed-off-by: David Cunado <david.cunado@arm.com>

SPE is only supported in non-secure state.  Accesses to SPE specific
registers from SEL1 will trap to EL3.  During a world switch, before
`TTBR` is modified the SPE profiling buffers are drained.  This is to
avoid a potential invalid memory access in SEL1.

SPE is architecturally specified only for AArch64.

Change-Id: I04a96427d9f9d586c331913d815fdc726855f6b0
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>

To make software license auditing simpler, use SPDX[0] license
identifiers instead of duplicating the license text in every file.

NOTE: Files that have been imported by FreeBSD have not been modified.

[0]: https://spdx.org/



Change-Id: I80a00e1f641b8cc075ca5a95b10607ed9ed8761a
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>

This patch moves the PSCI services and BL31 frameworks like context
management and per-cpu data into new library components `PSCI` and
`el3_runtime` respectively. This enables PSCI to be built independently from
BL31. A new `psci_lib.mk` makefile is introduced which adds the relevant
PSCI library sources and gets included by `bl31.mk`. Other changes which
are done as part of this patch are:

* The runtime services framework is now moved to the `common/` folder to
  enable reuse.
* The `asm_macros.S` and `assert_macros.S` helpers are moved to architecture
  specific folder.
* The `plat_psci_common.c` is moved from the `plat/common/aarch64/` folder
  to `plat/common` folder. The original file location now has a stub which
  just includes the file from new location to maintain platform compatibility.

Most of the changes wouldn't affect platform builds as they just involve
changes to the generic bl1.mk and bl31.mk makefiles.

NOTE: THE `plat_psci_common.c` FILE HAS MOVED LOCATION AND THE STUB FILE AT
THE ORIGINAL LOCATION IS NOW DEPRECATED. PLATFORMS SHOULD MODIFY THEIR
MAKEFILES TO INCLUDE THE FILE FROM THE NEW LOCATION.

Change-Id: I6bd87d5b59424995c6a65ef8076d4fda91ad5e86

The system registers that are saved and restored in CPU context include
AArch32 systems registers like SPSR_ABT, SPSR_UND, SPSR_IRQ, SPSR_FIQ,
DACR32_EL2, IFSR32_EL2 and FPEXC32_EL2. Accessing these registers on an
AArch64-only (i.e. on hardware that does not implement AArch32, or at
least not at EL1 and higher ELs) platform leads to an exception. This patch
introduces the build option `CTX_INCLUDE_AARCH32_REGS` to specify whether to
include these AArch32 systems registers in the cpu context or not. By default
this build option is set to 1 to ensure compatibility. AArch64-only platforms
must set it to 0. A runtime check is added in BL1 and BL31 cold boot path to
verify this.

Fixes ARM-software/tf-issues#386

Change-Id: I720cdbd7ed7f7d8516635a2ec80d025f478b95ee

Change-Id: I6f49bd779f2a4d577c6443dd160290656cdbc59b

The upcoming Firmware Update feature needs transitioning across
Secure/Normal worlds to complete the FWU process and hence requires
context management code to perform this task.

Currently context management code is part of BL31 stage only.
This patch moves the code from (include)/bl31 to (include)/common.
Some function declarations/definitions and macros have also moved
to different files to help code sharing.

Change-Id: I3858b08aecdb76d390765ab2b099f457873f7b0c

The `fpregs_context_restore()` function used to restore the floating point
regsiter context had a typo error wherein it was doing `str` instead of
`ldr` for a register. This issue remained undetected becuase none of the ARM
Standard development platforms save and restore the floating point register
context when a context switch is done. This patch corrects the issue.

Change-Id: Id178e0ba254a5e0a4a844f54b39d71dc34e0f6ea

In order for the symbol table in the ELF file to contain the size of
functions written in assembly, it is necessary to report it to the
assembler using the .size directive.

To fulfil the above requirements, this patch introduces an 'endfunc'
macro which contains the .endfunc and .size directives. It also adds
a .func directive to the 'func' assembler macro.

The .func/.endfunc have been used so the assembler can fail if
endfunc is omitted.

Fixes ARM-Software/tf-issues#295

Change-Id: If8cb331b03d7f38fe7e3694d4de26f1075b278fc
Signed-off-by: Kévin Petit <kevin.petit@arm.com>

This patch gathers miscellaneous minor fixes to the documentation, and comments
in the source code.

Change-Id: I631e3dda5abafa2d90f464edaee069a1e58b751b
Co-Authored-By: Soby Mathew <soby.mathew@arm.com>
Co-Authored-By: Dan Handley <dan.handley@arm.com>

This patch further optimizes the EL3 register state stored in
cpu_context. The 2 registers which are removed from cpu_context are:

  * cntfrq_el0 is the system timer register which is writable
    only in EL3 and it can be programmed during cold/warm boot. Hence
    it need not be saved to cpu_context.

  * cptr_el3 controls access to Trace, Floating-point, and Advanced
    SIMD functionality and it is programmed every time during cold
    and warm boot. The current BL3-1 implementation does not need to
    modify the access controls during normal execution and hence
    they are expected to remain static.

Fixes ARM-software/tf-issues#197

Change-Id: I599ceee3b73a7dcfd37069fd41b60e3d397a7b18

This patch uses stacks allocated in normal memory to enable the MMU early in the
warm boot path thus removing the dependency on stacks allocated in coherent
memory. Necessary cache and stack maintenance is performed when a cpu is being
powered down and up. This avoids any coherency issues that can arise from
reading speculatively fetched stale stack memory from another CPUs cache. These
changes affect the warm boot path in both BL3-1 and BL3-2.

The EL3 system registers responsible for preserving the MMU state are not saved
and restored any longer. Static values are used to program these system
registers when a cpu is powered on or resumed from suspend.

Change-Id: I8357e2eb5eb6c5f448492c5094b82b8927603784

CTX_INCLUDE_FPREGS make variable allows us to include or exclude FP
registers from context structure, in case FP is not used by TSPD.

Fixes ARM-software/tf-issues#194

Change-Id: Iee41af382d691340c7ae21830ad1bbf95dad1f4b

Consolidate all BL3-1 CPU context initialization for cold boot, PSCI
and SPDs into two functions:
*  The first uses entry_point_info to initialize the relevant
   cpu_context for first entry into a lower exception level on a CPU
*  The second populates the EL1 and EL2 system registers as needed
   from the cpu_context to ensure correct entry into the lower EL

This patch alters the way that BL3-1 determines which exception level
is used when first entering EL1 or EL2 during cold boot - this is now
fully determined by the SPSR value in the entry_point_info for BL3-3,
as set up by the platform code in BL2 (or otherwise provided to BL3-1).

In the situation that EL1 (or svc mode) is selected for a processor
that supports EL2, the context management code will now configure all
essential EL2 register state to ensure correct execution of EL1. This
allows the platform code to run non-secure EL1 payloads directly
without requiring a small EL2 stub or OS loader.

Change-Id: If9fbb2417e82d2226e47568203d5a369f39d3b0f

At present, non-secure timer register contents are saved and restored as
part of world switch by BL3-1. This effectively means that the
non-secure timer stops, and non-secure timer interrupts are prevented
from asserting until BL3-1 switches back, introducing latency for
non-secure services. Often, secure world might depend on alternate
sources for secure interrupts (secure timer or platform timer) instead
of non-secure timers, in which case this save and restore is
unnecessary.

This patch introduces a boolean build-time configuration NS_TIMER_SWITCH
to choose whether or not to save and restore non-secure timer registers
upon world switch. The default choice is made not to save and restore
them.

Fixes ARM-software/tf-issues#148

Change-Id: I1b9d623606acb9797c3e0b02fb5ec7c0a414f37e

Reduce the number of header files included from other header
files as much as possible without splitting the files. Use forward
declarations where possible. This allows removal of some unnecessary
"#ifndef __ASSEMBLY__" statements.

Also, review the .c and .S files for which header files really need
including and reorder the #include statements alphabetically.

Fixes ARM-software/tf-issues#31

Change-Id: Iec92fb976334c77453e010b60bcf56f3be72bd3e

This extends the --gc-sections behaviour to the many assembler
support functions in the firmware images by placing each function
into its own code section. This is achieved by creating a 'func'
macro used to declare each function label.

Fixes ARM-software/tf-issues#80

Change-Id: I301937b630add292d2dec6d2561a7fcfa6fec690