vdso/treewide: Add vdso_data pointer argument to __arch_get_hw_counter()

MIPS already uses and S390 will need the vdso data pointer in
__arch_get_hw_counter().

This works nicely as long as the architecture does not support time
namespaces in the VDSO. With time namespaces enabled the regular
accessor to the vdso data pointer __arch_get_vdso_data() will return the
namespace specific VDSO data page for tasks which are part of a
non-root time namespace. This would cause the architectures which need
the vdso data pointer in __arch_get_hw_counter() to access the wrong
vdso data page.

Add a vdso_data pointer argument to __arch_get_hw_counter() and hand it in
from the call sites in the core code. For architectures which do not need
the data pointer in their counter accessor function the compiler will just
optimize it out.

Fix up all existing architecture implementations and make MIPS utilize the
pointer instead of invoking the accessor function.

No functional change and no change in the resulting object code (except
MIPS).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/draft-87wo2ekuzn.fsf@nanos.tec.linutronix.de

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/arm/include/asm/vdso/gettimeofday.h b/arch/arm/include/asm/vdso/gettimeofday.h
index 1b207cf07697..2134cbd5469f 100644
--- a/arch/arm/include/asm/vdso/gettimeofday.h
+++ b/arch/arm/include/asm/vdso/gettimeofday.h
@@ -113,7 +113,8 @@ static inline bool arm_vdso_hres_capable(void)
 }
 #define __arch_vdso_hres_capable arm_vdso_hres_capable
 
-static __always_inline u64 __arch_get_hw_counter(int clock_mode)
+static __always_inline u64 __arch_get_hw_counter(int clock_mode,
+						 const struct vdso_data *vd)
 {
 #ifdef CONFIG_ARM_ARCH_TIMER
 	u64 cycle_now;