aarch32: Implement static workaround for CVE-2018-3639 ...

Implement static mitigation for CVE-2018-3639 on
Cortex A57 and A72.

Change-Id: I83409a16238729b84142b19e258c23737cc1ddc3
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

Implement static workaround for CVE-2018-3639 ...

For affected CPUs, this approach enables the mitigation during EL3
initialization, following every PE reset. No mechanism is provided to
disable the mitigation at runtime.

This approach permanently mitigates the entire software stack and no
additional mitigation code is required in other software components.

TF-A implements this approach for the following affected CPUs:

*   Cortex-A57 and Cortex-A72, by setting bit 55 (Disable load pass store) of
    `CPUACTLR_EL1` (`S3_1_C15_C2_0`).

*   Cortex-A73, by setting bit 3 of `S3_0_C15_C0_0` (not documented in the
    Technical Reference Manual (TRM)).

*   Cortex-A75, by setting bit 35 (reserved in TRM) of `CPUACTLR_EL1`
    (`S3_0_C15_C1_0`).

Additionally, a new SMC interface is implemented to allow software
executing in lower ELs to discover whether the system is mitigated
against CVE-2018-3639.

Refer to "Firmware interfaces for mitigating cache speculation
vulnerabilities System Software on Arm Systems"[0] for more
information.

[0] https://developer.arm.com/cache-speculation-vulnerability-firmware-specification

Change-Id: I084aa7c3bc7c26bf2df2248301270f77bed22ceb
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

Rename symbols and files relating to CVE-2017-5715 ...

This patch renames symbols and files relating to CVE-2017-5715 to make
it easier to introduce new symbols and files for new CVE mitigations.

Change-Id: I24c23822862ca73648c772885f1690bed043dbc7
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

Workaround for CVE-2017-5715 on NVIDIA Denver CPUs ...

Flush the indirect branch predictor and RSB on entry to EL3 by issuing
a newly added instruction for Denver CPUs. Support for this operation
can be determined by comparing bits 19:16 of ID_AFR0_EL1 with 0b0001.

To achieve this without performing any branch instruction, a per-cpu
vbar is installed which executes the workaround and then branches off
to the corresponding vector entry in the main vector table. A side
effect of this change is that the main vbar is configured before any
reset handling. This is to allow the per-cpu reset function to override
the vbar setting.

Change-Id: Ief493cd85935bab3cfee0397e856db5101bc8011
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>

Check presence of fix for errata 835769 in Cortex-A53 ...

A fix for errata 835769 may be available in revisions r0p2, r0p3 or r0p4
of the Cortex-A53 processor. The presence of the fix is determined by
checking bit 7 in the REVIDR register.

If the fix is present we report ERRATA_NOT_APPLIES which silences the
erroneous 'missing workaround' warning.

Change-Id: Ib75b008e755e9ac648554ca9398024fdbea4a91a
Signed-off-by: Jonathan Wright <jonathan.wright@arm.com>

Check presence of fix for errata 843419 in Cortex-A53 ...

A fix for errata 843419 may be available in revision r0p4 of the
Cortex-A53 processor. The presence of the fix is determined by checking
bit 8 in the REVIDR register.

If the fix is present we report ERRATA_NOT_APPLIES which silences the
erroneous 'missing workaround' warning.

Change-Id: Ibd2a478df3e2a6325442a6a48a0bb0259dcfc1d7
Signed-off-by: Jonathan Wright <jonathan.wright@arm.com>

Fixup `SMCCC_ARCH_FEATURES` semantics ...

When querying `SMCCC_ARCH_WORKAROUND_1` through `SMCCC_ARCH_FEATURES`,
return either:
  * -1 to indicate the PE on which `SMCCC_ARCH_FEATURES` is called
    requires firmware mitigation for CVE-2017-5715 but the mitigation
    is not compiled in.
  * 0 to indicate that firmware mitigation is required, or
  * 1 to indicate that no firmware mitigation is required.

This patch complies with v1.2 of the firmware interfaces
specification (ARM DEN 0070A).

Change-Id: Ibc32d6620efdac6c340758ec502d95554a55f02a
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

Use PFR0 to identify need for mitigation of CVE-2017-5715 ...

If the CSV2 field reads as 1 then branch targets trained in one
context cannot affect speculative execution in a different context.
In that case skip the workaround on Cortex A72 and A73.

Change-Id: Ide24fb6efc77c548e4296295adc38dca87d042ee
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

MISRA fixes for Cortex A75 AMU implementation ...

Change-Id: I61c9fdfda0c0b3c3ec6249519db23602cf4c2100
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

Refactor AMU support for Cortex A75 ...

This patch also fixes the assumption that the counters are disabled on
the resume path.  This is incorrect as the AMU counters are enabled
early in the CPU reset function before `cpuamu_context_restore()`
runs.

Change-Id: I38a94eb166a523f00de18e86860434ffccff2131
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

Factor out CPU AMU helpers ...

This patch also fixes `cpuamu_write_cpuamcntenclr_el0()` to use an MSR
instruction instead of an MRS instruction.

Change-Id: Ia6531f64b5ebc60ba432124eaa8d8eaccba40ed0
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

Fixup AArch32 errata printing framework ...

The AArch32 assembly implementation of `print_errata_status` did not save
a register which was getting clobbered by a `get_cpu_ops_ptr`. This
patch fixes that.

Change-Id: Id0711e46b7c685a18a10328d4b513e952a5d860b
Signed-off-by: Soby Mathew <soby.mathew@arm.com>

Merge pull request #1253 from dp-arm/dp/amu32 ...

AMUv1 support for AArch32

AMU: Implement context save/restore for aarch32 ...

Add amu_context_save() and amu_context_restore() functions for aarch32

Change-Id: I4df83d447adeaa9d9f203e16dc5a919ffc04d87a
Signed-off-by: Joel Hutton <joel.hutton@arm.com>

Optimize SMCCC_ARCH_WORKAROUND_1 on Cortex A57/A72/A73 and A75 ...

This patch implements a fast path for this SMC call on affected PEs by
detecting and returning immediately after executing the workaround.

NOTE: The MMU disable/enable workaround now assumes that the MMU was
enabled on entry to EL3.  This is a valid assumption as the code turns
on the MMU after reset and leaves it on until the core powers off.

Change-Id: I13c336d06a52297620a9760fb2461b4d606a30b3
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

Optimize/cleanup BPIALL workaround ...

In the initial implementation of this workaround we used a dedicated
workaround context to save/restore state.  This patch reduces the
footprint as no additional context is needed.

Additionally, this patch reduces the memory loads and stores by 20%,
reduces the instruction count and exploits static branch prediction to
optimize the SMC path.

Change-Id: Ia9f6bf06fbf8a9037cfe7f1f1fb32e8aec38ec7d
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

Merge pull request #1228 from dp-arm/dp/cve_2017_5715 ...

Workarounds for CVE-2017-5715 on A9/A15 and A17 + serial console reporting

Merge pull request #1229 from manojkumar-arm/manojkumar-arm/ca72-aarch32-reset-fix ...

lib/cpus: fix branching in reset function for cortex-a72 AARCH32 mode

Merge pull request #1200 from robertovargas-arm/bl2-el3 ...

Add BL2_AT_EL3 build option

lib/cpus: fix branching in reset function for cortex-a72 AARCH32 mode ...

In AARCH32 mode, cortex_a72_reset_func branches to address in lr
register instead of r5 register. This leads to linux boot failure
of Cortex-A72 cores in AARCH32 mode on Juno-R2 board.

This patch fixes the branching of cortex_a72_reset_func to r5
register as in cortex_a57_reset_func implementation.

Signed-off-by: Manoj Kumar <manoj.kumar3@arm.com>

Workaround for CVE-2017-5715 for Cortex A9, A15 and A17 ...

A per-cpu vbar is installed that implements the workaround by
invalidating the branch target buffer (BTB) directly in the case of A9
and A17 and indirectly by invalidating the icache in the case of A15.

For Cortex A57 and A72 there is currently no workaround implemented
when EL3 is in AArch32 mode so report it as missing.

For other vulnerable CPUs (e.g. Cortex A73 and Cortex A75), there are
no changes since there is currently no upstream AArch32 EL3 support
for these CPUs.

Change-Id: Ib42c6ef0b3c9ff2878a9e53839de497ff736258f
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

Print erratum application report for CVE-2017-5715 ...

Even though the workaround for CVE-2017-5715 is not a CPU erratum, the
code is piggybacking on the errata framework to print whether the
workaround was applied, missing or not needed.

Change-Id: I821197a4b8560c73fd894cd7cd9ecf9503c72fa3
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

Change the default errata format string ...

As we are using the errata framework to handle workarounds in a more
general sense, change the default string to reflect that.

Change-Id: I2e266af2392c9d95e18fe4e965f9a1d46fd0e95e
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

bl2-el3: Add BL2_EL3 image ...

This patch enables BL2 to execute at the highest exception level
without any dependancy on TF BL1. This enables platforms which already
have a non-TF Boot ROM to directly load and execute BL2 and subsequent BL
stages without need for BL1.  This is not currently possible because
BL2 executes at S-EL1 and cannot jump straight to EL3.

Change-Id: Ief1efca4598560b1b8c8e61fbe26d1f44e929d69
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>

Merge pull request #1197 from dp-arm/dp/amu ...

AMUv1 support

Add hooks to save/restore AMU context for Cortex A75 ...

Change-Id: I504d3f65ca5829bc1f4ebadb764931f8379ee81f
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

Use PFR0 to identify need for mitigation of CVE-2017-5915 ...

If the CSV2 field reads as 1 then branch targets trained in one
context cannot affect speculative execution in a different context.
In that case skip the workaround on Cortex A75.

Change-Id: I4d5504cba516a67311fb5f0657b08f72909cbd38
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

Workaround for CVE-2017-5715 on Cortex A73 and A75 ...

Invalidate the Branch Target Buffer (BTB) on entry to EL3 by
temporarily dropping into AArch32 Secure-EL1 and executing the
`BPIALL` instruction.

This is achieved by using 3 vector tables.  There is the runtime
vector table which is used to handle exceptions and 2 additional
tables which are required to implement this workaround.  The
additional tables are `vbar0` and `vbar1`.

The sequence of events for handling a single exception is
as follows:

1) Install vector table `vbar0` which saves the CPU context on entry
   to EL3 and sets up the Secure-EL1 context to execute in AArch32 mode
   with the MMU disabled and I$ enabled.  This is the default vector table.

2) Before doing an ERET into Secure-EL1, switch vbar to point to
   another vector table `vbar1`.  This is required to restore EL3 state
   when returning from the workaround, before proceeding with normal EL3
   exception handling.

3) While in Secure-EL1, the `BPIALL` instruction is executed and an
   SMC call back to EL3 is performed.

4) On entry to EL3 from Secure-EL1, the saved context from step 1) is
   restored.  The vbar is switched to point to `vbar0` in preparation to
   handle further exceptions.  Finally a branch to the runtime vector
   table entry is taken to complete the handling of the original
   exception.

This workaround is enabled by default on the affected CPUs.

NOTE
====

There are 4 different stubs in Secure-EL1.  Each stub corresponds to
an exception type such as Sync/IRQ/FIQ/SError.  Each stub will move a
different value in `R0` before doing an SMC call back into EL3.
Without this piece of information it would not be possible to know
what the original exception type was as we cannot use `ESR_EL3` to
distinguish between IRQs and FIQs.

Change-Id: I90b32d14a3735290b48685d43c70c99daaa4b434
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

Workaround for CVE-2017-5715 on Cortex A57 and A72 ...

Invalidate the Branch Target Buffer (BTB) on entry to EL3 by disabling
and enabling the MMU.  To achieve this without performing any branch
instruction, a per-cpu vbar is installed which executes the workaround
and then branches off to the corresponding vector entry in the main
vector table.  A side effect of this change is that the main vbar is
configured before any reset handling.  This is to allow the per-cpu
reset function to override the vbar setting.

This workaround is enabled by default on the affected CPUs.

Change-Id: I97788d38463a5840a410e3cea85ed297a1678265
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

Merge pull request #1168 from matt2048/master ...

Replace macro ASM_ASSERTION with macro ENABLE_ASSERTIONS