[PATCH 7/7] arm64/boot: Enable EL2 requirements for FEAT_PMUv3p9

[Rob Herring]

On Fri, Dec 20, 2024 at 12:52:40PM +0530, Anshuman Khandual wrote:
> FEAT_PMUv3p9 registers such as PMICNTR_EL0, PMICFILTR_EL0, and PMUACR_EL1
> access from EL1 requires appropriate EL2 fine grained trap configuration
> via FEAT_FGT2 based trap control registers HDFGRTR2_EL2 and HDFGWTR2_EL2.
> Otherwise such register accesses will result in traps into EL2.
> 
> Add a new helper __init_el2_fgt2() which initializes FEAT_FGT2 based fine
> grained trap control registers HDFGRTR2_EL2 and HDFGWTR2_EL2 (setting the
> bits nPMICNTR_EL0, nPMICFILTR_EL0 and nPMUACR_EL1) to enable access into
> PMICNTR_EL0, PMICFILTR_EL0, and PMUACR_EL1 registers.
> 
> Also update booting.rst with SCR_EL3.FGTEn2 requirement for all FEAT_FGT2
> based registers to be accessible in EL2.
> 
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Cc: Will Deacon <will at kernel.org>
> Cc: Mark Rutland <mark.rutland at arm.com>
> Cc: Rob Herring <robh at kernel.org>
> Cc: Jonathan Corbet <corbet at lwn.net>
> Cc: Marc Zyngier <maz at kernel.org>
> Cc: Oliver Upton <oliver.upton at linux.dev>
> Cc: linux-arm-kernel at lists.infradead.org
> Cc: linux-doc at vger.kernel.org
> Cc: linux-kernel at vger.kernel.org
> Cc: kvmarm at lists.linux.dev
> Signed-off-by: Anshuman Khandual <anshuman.khandual at arm.com>
> ---
>  Documentation/arch/arm64/booting.rst | 18 ++++++++++++++++++
>  arch/arm64/include/asm/el2_setup.h   | 25 +++++++++++++++++++++++++
>  2 files changed, 43 insertions(+)

Tested-by: Rob Herring (Arm) <robh at kernel.org>
Reviewed-by: Rob Herring (Arm) <robh at kernel.org>