ARM: arch_timer: stop virtual timer when booted in HYP mode

When booting the kernel, a bootloader could have left the virtual
timer ticking away, potentially generating interrupts. This could
be troublesome if the user of the virtual timer is not careful
when enabling the interrupt.

In order to avoid any surprise, stop the virtual timer from
interrupting us when booted in HYP mode, as we'll use the physical
timer in this case.

Reported-by: Giridhar Maruthy <giridhar.m@samsung.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Dave Martin <dave.martin@linaro.org>

diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index dbe2110..4910232 100644 (file)
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -155,6 +155,11 @@ THUMB(     orr     r7, #(1 << 30)  )       @ HSCTLR.TE
        mcr     p15, 4, r7, c14, c1, 0  @ CNTHCTL
        mov     r7, #0
        mcrr    p15, 4, r7, r7, c14     @ CNTVOFF
+
+       @ Disable virtual timer in case it was counting
+       mrc     p15, 0, r7, c14, c3, 1  @ CNTV_CTL
+       bic     r7, #1                  @ Clear ENABLE
+       mcr     p15, 0, r7, c14, c3, 1  @ CNTV_CTL
 1:
 #endif