On 04/09/2024 16:05, Christophe Leroy wrote: > > > Le 04/09/2024 à 16:52, Arnd Bergmann a écrit : >> On Tue, Sep 3, 2024, at 15:14, Vincenzo Frascino wrote: >> ... >>> + >>> +#ifndef __ASSEMBLY__ >>> + >>> +#include <asm/page_types.h> >>> + >>> +#define VDSO_PAGE_MASK PAGE_MASK >>> +#define VDSO_PAGE_SIZE PAGE_SIZE >>> + >>> +#endif /* !__ASSEMBLY__ */ >>> + >>> +#endif /* __ASM_VDSO_PAGE_H */ >> >> I don't get this one: the x86 asm/page_types.h still includes other >> headers outside of the vdso namespace, but you seem to only need these >> two definitions that are the same across everything. >> >> Why not put PAGE_MASK and PAGE_SIZE into a global vdso/page.h >> header? I did spend a lot of time a few months ago ensuring that >> we can have a single definition for all architectures based on >> CONFIG_PAGE_SHIFT, so all the extra copies should just go away. >> > > Just wondering, after looking at x86, powerpc and arm64, is there any difference > between: > > X86,ARM64: > #define PAGE_SIZE (_AC(1,UL) << PAGE_SHIFT) > #define PAGE_MASK (~(PAGE_SIZE-1)) > > POWERPC: > #define PAGE_SIZE (ASM_CONST(1) << PAGE_SHIFT) > /* > * Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we > * assign PAGE_MASK to a larger type it gets extended the way we want > * (i.e. with 1s in the high bits) > */ > #define PAGE_MASK (~((1 << PAGE_SHIFT) - 1)) > > > Which one should be taken in vdso/page.h ? > I am not sure either on this point. That's the main reason why I proposed an indirection for the definitions. > Christophe -- Regards, Vincenzo
