VIPT caches are non-aliasing if the index is derived from address bits that
are always equal between VA and PA. Classifying these as aliasing results in
unnecessary flushing which may hurt performance.
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

This adds helper functions and #defines to <asm/cachetype.h> to read the
line size and the number of sets from the level 1 instruction cache.
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

This removes an unfortunately placed semi-colon resulting in all instruction
caches being classified as AIVIVT.
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Due to a missing newline in the I-cache policy detection log output,
it's possible to get some ratehr unfortunate output at boot time:

CPU1: Booted secondary processor
Detected VIPT I-cache on CPU1CPU2: Booted secondary processor
Detected VIPT I-cache on CPU2CPU3: Booted secondary processor
Detected VIPT I-cache on CPU3CPU4: Booted secondary processor
Detected PIPT I-cache on CPU4CPU5: Booted secondary processor
Detected PIPT I-cache on CPU5Brought up 6 CPUs
SMP: Total of 6 processors activated.

This patch adds the missing newline to the format string, cleaning up
the output.

Fixes: 59ccc0d4 ("arm64: cachetype: report weakest cache policy")
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Unexpected variation in certain system register values across CPUs is an
indicator of potential problems with a system. The kernel expects CPUs
to be mostly identical in terms of supported features, even in systems
with heterogeneous CPUs, with uniform instruction set support being
critical for the correct operation of userspace.

To help detect issues early where hardware violates the expectations of
the kernel, this patch adds simple runtime sanity checks on important ID
registers in the bring up path of each CPU.

Where CPUs are fundamentally mismatched, set TAINT_CPU_OUT_OF_SPEC.
Given that the kernel assumes CPUs are identical feature wise, let's not
pretend that we expect such configurations to work. Supporting such
configurations would require massive rework, and hopefully they will
never exist.
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Reviewed-by: NWill Deacon <will.deacon@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

In big.LITTLE systems, the I-cache policy may differ across CPUs, and
thus we must always meet the most stringent maintenance requirements of
any I-cache in the system when performing maintenance to ensure
correctness. Unfortunately this requirement is not met as we always look
at the current CPU's cache type register to determine the maintenance
requirements.

This patch causes the I-cache policy of all CPUs to be taken into
account for icache_is_aliasing and icache_is_aivivt. If any I-cache in
the system is aliasing or AIVIVT, the respective function will return
true. At boot each CPU may set flags to identify that at least one
I-cache in the system is aliasing and/or AIVIVT.

The now unused and potentially misleading icache_policy function is
removed.
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
Reviewed-by: NWill Deacon <will.deacon@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

Several kernel subsystems need to know details about CPU system register
values, sometimes for CPUs other than that they are executing on. Rather
than hard-coding system register accesses and cross-calls for these
cases, this patch adds logic to record various system register values at
boot-time. This may be used for feature reporting, firmware bug
detection, etc.

Separate hooks are added for the boot and hotplug paths to enable
one-time intialisation and cold/warm boot value mismatch detection in
later patches.
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Reviewed-by: NWill Deacon <will.deacon@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>