Commit d10bcd47 authored by Will Deacon's avatar Will Deacon
Browse files

arm64: head.S: initialise mdcr_el2 in el2_setup

When entering the kernel at EL2, we fail to initialise the MDCR_EL2
register which controls debug access and PMU capabilities at EL1.

This patch ensures that the register is initialised so that all traps
are disabled and all the PMU counters are available to the host. When a
guest is scheduled, KVM takes care to configure trapping appropriately.

Cc: <>
Acked-by: default avatarMarc Zyngier <>
Signed-off-by: default avatarWill Deacon <>
parent 2314ee4d
......@@ -523,6 +523,11 @@ CPU_LE( movk x0, #0x30d0, lsl #16 ) // Clear EE and E0E on LE systems
msr hstr_el2, xzr // Disable CP15 traps to EL2
/* EL2 debug */
mrs x0, pmcr_el0 // Disable debug access traps
ubfx x0, x0, #11, #5 // to EL2 and allow access to
msr mdcr_el2, x0 // all PMU counters from EL1
/* Stage-2 translation */
msr vttbr_el2, xzr
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment