Print the message about disabled Spectre workarounds only once. The
message is printed each time CPU goes out from idling state on NVIDIA
Tegra boards, causing storm in KMSG that makes system unusable.
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Jon reports that the Spectre-BHB init code is filling up the kernel log
with spurious notifications about which mitigation has been enabled,
every time any CPU comes out of a low power state.
Given that Spectre-BHB mitigations are system wide, only a single
mitigation can be enabled, and we already print an error if two types of
CPUs coexist in a single system that require different Spectre-BHB
mitigations.
This means that the pr_info() that describes the selected mitigation
does not need to be emitted for each CPU anyway, and so we can simply
emit it only once.
In order to clarify the above in the log message, update it to describe
that the selected mitigation will be enabled on all CPUs, including ones
that are unaffected. If another CPU comes up later that is affected and
requires a different mitigation, we report an error as before.
Fixes: b9baf5c8c5 ("ARM: Spectre-BHB workaround")
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
The Spectre-BHB mitigations were inadvertently left disabled for
Cortex-A15, due to the fact that cpu_v7_bugs_init() is not called in
that case. So fix that.
Fixes: b9baf5c8c5 ("ARM: Spectre-BHB workaround")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
The kernel test robot discovered that building without
HARDEN_BRANCH_PREDICTOR issues a warning due to a missing
argument to pr_info().
Add the missing argument.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 9dd78194a3 ("ARM: report Spectre v2 status through sysfs")
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Workaround the Spectre BHB issues for Cortex-A15, Cortex-A57,
Cortex-A72, Cortex-A73 and Cortex-A75. We also include Brahma B15 as
well to be safe, which is affected by Spectre V2 in the same ways as
Cortex-A15.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
As per other architectures, add support for reporting the Spectre
vulnerability status via sysfs CPU.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
When the default processor handling was added to the function
cpu_v7_spectre_init() it only excluded other ARM implemented processor
cores. The Broadcom Brahma B53 core is not implemented by ARM so it
ended up falling through into the set of processors that attempt to use
the ARM_SMCCC_ARCH_WORKAROUND_1 service to harden the branch predictor.
Since this workaround is not necessary for the Brahma-B53 this commit
explicitly checks for it and prevents it from applying a branch
predictor hardening workaround.
Fixes: 10115105cb ("ARM: spectre-v2: add firmware based hardening")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Rather than directly choosing which function to use based on
psci_ops.conduit, use the new arm_smccc_1_1 wrapper instead.
In some cases we still need to do some operations based on the
conduit, but the code duplication is removed.
No functional change.
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Now that we have arm_smccc_1_1_get_conduit(), we can hide the PSCI
implementation details from the arm spectre-v2 code, so let's do so.
As arm_smccc_1_1_get_conduit() implicitly checks that the SMCCC version
is at least SMCCC_VERSION_1_1, we no longer need to check this
explicitly where switch statements have a default case.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
In big.Little systems, some CPUs require the Spectre workarounds in
paths such as the context switch, but other CPUs do not. In order
to handle these differences, we need per-CPU vtables.
We are unable to use the kernel's per-CPU variables to support this
as per-CPU is not initialised at times when we need access to the
vtables, so we have to use an array indexed by logical CPU number.
We use an array-of-pointers to avoid having function pointers in
the kernel's read/write .data section.
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Warn at error level if the context switching function is not what we
are expecting. This can happen with big.Little systems, which we
currently do not support.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Add firmware based hardening for cores that require more complex
handling in firmware.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
In order to prevent aliasing attacks on the branch predictor,
invalidate the BTB or instruction cache on CPUs that are known to be
affected when taking an abort on a address that is outside of a user
task limit:
Cortex A8, A9, A12, A17, A73, A75: flush BTB.
Cortex A15, Brahma B15: invalidate icache.
If the IBE bit is not set, then there is little point to enabling the
workaround.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
When the branch predictor hardening is enabled, firmware must have set
the IBE bit in the auxiliary control register. If this bit has not
been set, the Spectre workarounds will not be functional.
Add validation that this bit is set, and print a warning at alert level
if this is not the case.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Dmitry Osipenko