[PATCH v5 2/7] arm64: head.S: Initialise MPAM EL2 registers and disable traps

[Gavin Shan]

On 10/15/24 11:39 PM, Joey Gouly wrote:
> From: James Morse <james.morse at arm.com>
> 
> Add code to head.S's el2_setup to detect MPAM and disable any EL2 traps.
> This register resets to an unknown value, setting it to the default
> parititons/pmg before we enable the MMU is the best thing to do.
> 
> Kexec/kdump will depend on this if the previous kernel left the CPU
> configured with a restrictive configuration.
> 
> If linux is booted at the highest implemented exception level el2_setup
> will clear the enable bit, disabling MPAM.
> 
> This code can't be enabled until a subsequent patch adds the Kconfig
> and cpufeature boiler plate.
> 
> Signed-off-by: James Morse <james.morse at arm.com>
> Signed-off-by: Joey Gouly <joey.gouly at arm.com>
> ---
>   arch/arm64/include/asm/el2_setup.h | 16 ++++++++++++++++
>   1 file changed, 16 insertions(+)
> 

Reviewed-by: Gavin Shan <gshan at redhat.com>