vdso: Use CONFIG_PAGE_SHIFT in vdso/datapage.h

Both the vdso rework and the CONFIG_PAGE_SHIFT changes were merged during
the v6.9 merge window, so it is now possible to use CONFIG_PAGE_SHIFT
instead of including asm/page.h in the vdso.

This avoids the workaround for arm64 - commit 8b3843ae3634 ("vdso/datapage:
Quick fix - use asm/page-def.h for ARM64") and addresses a build warning
for powerpc64:

In file included from <built-in>:4:
In file included from /home/arnd/arm-soc/arm-soc/lib/vdso/gettimeofday.c:5:
In file included from ../include/vdso/datapage.h:25:
arch/powerpc/include/asm/page.h:230:9: error: result of comparison of constant 13835058055282163712 with expression of type 'unsigned long' is always true [-Werror,-Wtautological-constant-out-of-range-compare]
230 | return __pa(kaddr) >> PAGE_SHIFT;
| ^~~~~~~~~~~
arch/powerpc/include/asm/page.h:217:37: note: expanded from macro '__pa'
217 | VIRTUAL_WARN_ON((unsigned long)(x) < PAGE_OFFSET); \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~
arch/powerpc/include/asm/page.h:202:73: note: expanded from macro 'VIRTUAL_WARN_ON'
202 | #define VIRTUAL_WARN_ON(x) WARN_ON(IS_ENABLED(CONFIG_DEBUG_VIRTUAL) && (x))
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
arch/powerpc/include/asm/bug.h:88:25: note: expanded from macro 'WARN_ON'
88 | int __ret_warn_on = !!(x); \
| ^

Signed-off-by: Arnd Bergmann <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>
Reviewed-by: Kees Cook <[e-mail]>
Acked-by: Michael Ellerman <[e-mail]> (powerpc)
Link: https://lore.kernel.org/r/[e-mail]

arch/powerpc/include/asm/vdso/gettimeofday.h

···
 
 #ifndef __ASSEMBLY__
 
-#include <asm/page.h>
 #include <asm/vdso/timebase.h>
 #include <asm/barrier.h>
 #include <asm/unistd.h>
···
 static __always_inline
 const struct vdso_data *__arch_get_timens_vdso_data(const struct vdso_data *vd)
 {
-	return (void *)vd + PAGE_SIZE;
+	return (void *)vd + (1U << CONFIG_PAGE_SHIFT);
 }
 #endif
 

include/vdso/datapage.h

···
 #include <vdso/time32.h>
 #include <vdso/time64.h>
 
-#ifdef CONFIG_ARM64
-#include <asm/page-def.h>
-#else
-#include <asm/page.h>
-#endif
-
 #ifdef CONFIG_ARCH_HAS_VDSO_DATA
 #include <asm/vdso/data.h>
 #else
···
  */
 union vdso_data_store {
 	struct vdso_data	data[CS_BASES];
-	u8			page[PAGE_SIZE];
+	u8			page[1U << CONFIG_PAGE_SHIFT];
 };
 
 /*