In order to support vDSO, hv_read_tsc_page() should be able to be called from userspace if tsc page mapped. As a result, hv_get_raw_timer(), called by hv_read_tsc_page() requires to be called by both kernel and vDSO. Currently, it's defined as arch_timer_read_counter(), which is a function pointer initialized (using a kernel address) by the arch timer driver, therefore not usable in vDSO. Fix this by allowing a previous definition to override the default one, so that in vDSO code, we can define it as a function callable in userspace. Signed-off-by: Boqun Feng (Microsoft) <boqun.feng@xxxxxxxxx> --- arch/arm64/include/asm/mshyperv.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/mshyperv.h index a8468a611912..9cc4aeddf2d0 100644 --- a/arch/arm64/include/asm/mshyperv.h +++ b/arch/arm64/include/asm/mshyperv.h @@ -97,8 +97,15 @@ extern void hv_get_vpreg_128(u32 reg, struct hv_get_vp_register_output *result); #define hv_disable_stimer0_percpu_irq(irq) disable_percpu_irq(irq) #endif -/* ARM64 specific code to read the hardware clock */ +/* + * ARM64 specific code to read the hardware clock. + * + * This could be used in both kernel space and userspace (vDSO), so make it + * possible for a previous definition to override the default one. + */ +#ifndef hv_get_raw_timer #define hv_get_raw_timer() arch_timer_read_counter() +#endif #include <asm-generic/mshyperv.h> -- 2.24.0
