GitLab

Initial Spectre Variant 1 mitigations (CVE-2017-5753).
A potential speculative data leak was found in PSCI code, this depends
on a non-robust implementation of the `plat_get_core_pos_by_mpidr()`
function. This is considered very low-risk. This patch adds a macro to
mitigate this. Note not all code paths could be analyzed with current
tools.

Add a macro which makes a variable 'speculation safe', using the
 __builtin_speculation_safe_value function of GCC and llvm. This will be
available in GCC 9, and is planned for llvm, but is not currently in
mainline GCC or llvm. In order to implement this mitigation the compiler
must support this builtin. Support is indicated by the
__HAVE_SPECULATION_SAFE_VALUE flag.

The -mtrack-speculation option maintains a 'tracker' register, which
determines if the processor is in false speculation at any point. This
adds instructions and increases code size, but avoids the performance
impact of a hard barrier.

Without the -mtrack-speculation option, __builtin_speculation_safe_value
expands to a

    ISB
    DSB SY

sequence after a conditional branch, before the
speculation safe variable is used. With -mtrack-speculation a

    CSEL tracker, tracker, XZR, [cond];
    AND safeval,tracker;
    CSDB

sequence is added instead, clearing the vulnerable variable by
AND'ing it with the tracker register, which is zero during speculative
execution. [cond] are the status flags which will only be true during
speculative execution. For more information on
__builtin_speculation_safe_value and the -mtrack-speculation option see
https://developer.arm.com/support/arm-security-updates/speculative-processor-vulnerability/compiler-support-for-mitigations



The -mtracking option was not added, as the performance impact of the
mitigation is low, and there is only one occurence.

Change-Id: Ic9e66d1f4a5155e42e3e4055594974c230bfba3c
Signed-off-by: Joel Hutton <Joel.Hutton@Arm.com>

MISRA C-2012 Rules 10.1, 10.3 and 20.7.

Change-Id: I972ce63f0d8fa157ed17e826b84f218fe498c517
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

Initializes each element of the last_cpu_in_non_cpu_pd array in PSCI
stat implementation to -1, the reset value. This satisfies MISRA rule
9.3.

Previously, only the first element of the array was initialized to -1.

Change-Id: I666c71e6c073710c67c6d24c07a219b1feb5b773
Signed-off-by: Jonathan Wright <jonathan.wright@arm.com>

Call svc_suspend_finish if registered.
psci_get_stat() is static to psci_stat.c
Fix types used in comparison.
Fix coding style (empty line between variable definition and instructions
block).
Signed-off-by: Etienne Carriere <etienne.carriere@st.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 introduces the following three platform interfaces:

* void plat_psci_stat_accounting_start(const psci_power_state_t *state_info)

  This is an optional hook that platforms can implement in order
  to perform accounting before entering a low power state.  This
  typically involves capturing a timestamp.

* void plat_psci_stat_accounting_stop(const psci_power_state_t *state_info)

  This is an optional hook that platforms can implement in order
  to perform accounting after exiting from a low power state.  This
  typically involves capturing a timestamp.

* u_register_t plat_psci_stat_get_residency(unsigned int lvl,
	const psci_power_state_t *state_info,
	unsigned int last_cpu_index)

  This is an optional hook that platforms can implement in order
  to calculate the PSCI stat residency.

If any of these interfaces are overridden by the platform, it is
recommended that all of them are.

By default `ENABLE_PSCI_STAT` is disabled.  If `ENABLE_PSCI_STAT`
is set but `ENABLE_PMF` is not set then an alternative PSCI stat
collection backend must be provided.  If both are set, then default
weak definitions of these functions are provided, using PMF to
calculate the residency.

NOTE: Previously, platforms did not have to explicitly set
`ENABLE_PMF` since this was automatically done by the top-level
Makefile.

Change-Id: I17b47804dea68c77bc284df15ee1ccd66bc4b79b
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>

This patch adds a runtime check that psci_find_target_suspend_lvl()
returns a valid value back to psci_cpu_suspend() and psci_get_stat().
If it is invalid, BL31 will now panic.

Note that on the PSCI CPU suspend path there is already a debug
assertion checking the validity of the target composite power state,
which effectively also checks the validity of the target suspend level.
Therefore, the error condition would already be caught in debug builds,
but in a release build this assertion would be compiled out.

On the PSCI stat path, there is currently no debug assertion checking
the validity of the power state before using it as an index into
the power domain state array.

Although BL31 platforms ports are responsible for validating the
power state parameter, the security impact (i.e. an out-of-bounds
array access) of a potential platform port bug in this code would
be quite high, given that this parameter comes from an untrusted
source. The cost of checking this in runtime generic code is low.

Change-Id: Icea85b8020e39928ac03ec0cd49805b5857b3906

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

This patch adds following optional PSCI STAT functions:

- PSCI_STAT_RESIDENCY: This call returns the amount of time spent
  in power_state in microseconds, by the node represented by the
  `target_cpu` and the highest level of `power_state`.

- PSCI_STAT_COUNT: This call returns the number of times a
  `power_state` has been used by the node represented by the
  `target_cpu` and the highest power level of `power_state`.

These APIs provides residency statistics for power states that has
been used by the platform. They are implemented according to v1.0
of the PSCI specification.

By default this optional feature is disabled in the PSCI
implementation. To enable it, set the boolean flag
`ENABLE_PSCI_STAT` to 1. This also sets `ENABLE_PMF` to 1.

Change-Id: Ie62e9d37d6d416ccb1813acd7f616d1ddd3e8aff