4.2.8-ckt3 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------ From: Will Deacon <[email protected]> commit d8d23fa0f27f3b2942a7bbc7378c7735324ed519 upstream. We don't want to expose the DCC to userspace, particularly as there is a kernel console driver for it. This patch resets mdscr_el1 to disable userspace access to the DCC registers on the cold boot path. Signed-off-by: Will Deacon <[email protected]> [ kamal: 4.2-stable prereq for 60792ad arm64: kernel: enforce pmuserenr_el0 initialization and restore ] Signed-off-by: Kamal Mostafa <[email protected]> --- arch/arm64/mm/proc.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 39139a3..f28a1fe 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -156,7 +156,8 @@ ENTRY(__cpu_setup) mov x0, #3 << 20 msr cpacr_el1, x0 // Enable FP/ASIMD - msr mdscr_el1, xzr // Reset mdscr_el1 + mov x0, #1 << 12 // Reset mdscr_el1 and disable + msr mdscr_el1, x0 // access to the DCC from EL0 /* * Memory region attributes for LPAE: * -- 1.9.1
