Messages in this thread Patch in this message | | | Date | Mon, 11 Oct 2021 14:33:09 +0100 | From | Catalin Marinas <> | Subject | Re: [PATCH] arm64: asm: vdso: gettimeofday: export common variables |
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On Mon, Oct 11, 2021 at 02:47:56PM +0200, Arnd Bergmann wrote: > On Mon, Oct 11, 2021 at 12:03 PM Will Deacon <will@kernel.org> wrote: > > On Thu, Oct 07, 2021 at 09:57:54PM +0200, Anders Roxell wrote: > > > When building the kernel with sparse enabled 'C=1' the following > > > warnings can be seen: > > > > > > arch/arm64/kernel/vdso/vgettimeofday.c:9:5: warning: symbol '__kernel_clock_gettime' was not declared. Should it be static? > > > arch/arm64/kernel/vdso/vgettimeofday.c:15:5: warning: symbol '__kernel_gettimeofday' was not declared. Should it be static? > > > arch/arm64/kernel/vdso/vgettimeofday.c:21:5: warning: symbol '__kernel_clock_getres' was not declared. Should it be static? > > > > > > Rework so the variables are exported, since these variables are > > > created and used in vdso/vgettimeofday.c, also used in vdso.lds.S. > > > > Hmm, these functions are part of the vDSO and shouldn't be called from the > > kernel, so I don't think it makes sense to add prototypes for them to a > > kernel header, to be honest. > > It's a recurring problem, and I have recommended this method to Anders as > I don't see any of the alternatives as better. > > The thing is that both sparse (with make C=1) and gcc/clang (with make W=1) > warn about missing prototypes, and this catches a lot of real bugs. I hope > that we can eventually get to the point of enabling the warning by default for > all files, but that means we need a declaration for each global function and > variable.
I don't think there's anything in the asm/vdso/gettimeofday.h that is required by the kernel. However, it gets dragged in via the datapage.h. If I got it right, something like this should avoid it and we can include the prototypes:
diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h index 73eb622e7663..a8d26d7d042d 100644 --- a/include/vdso/datapage.h +++ b/include/vdso/datapage.h @@ -121,22 +121,6 @@ struct vdso_data { extern struct vdso_data _vdso_data[CS_BASES] __attribute__((visibility("hidden"))); extern struct vdso_data _timens_data[CS_BASES] __attribute__((visibility("hidden"))); -/* - * The generic vDSO implementation requires that gettimeofday.h - * provides: - * - __arch_get_vdso_data(): to get the vdso datapage. - * - __arch_get_hw_counter(): to get the hw counter based on the - * clock_mode. - * - gettimeofday_fallback(): fallback for gettimeofday. - * - clock_gettime_fallback(): fallback for clock_gettime. - * - clock_getres_fallback(): fallback for clock_getres. - */ -#ifdef ENABLE_COMPAT_VDSO -#include <asm/vdso/compat_gettimeofday.h> -#else -#include <asm/vdso/gettimeofday.h> -#endif /* ENABLE_COMPAT_VDSO */ - #endif /* !__ASSEMBLY__ */ #endif /* __VDSO_DATAPAGE_H */ diff --git a/include/vdso/gettimeofday.h b/include/vdso/gettimeofday.h new file mode 100644 index 000000000000..0270da504fe3 --- /dev/null +++ b/include/vdso/gettimeofday.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * The generic vDSO implementation requires that gettimeofday.h + * provides: + * - __arch_get_vdso_data(): to get the vdso datapage. + * - __arch_get_hw_counter(): to get the hw counter based on the + * clock_mode. + * - gettimeofday_fallback(): fallback for gettimeofday. + * - clock_gettime_fallback(): fallback for clock_gettime. + * - clock_getres_fallback(): fallback for clock_getres. + */ +#ifdef ENABLE_COMPAT_VDSO +#include <asm/vdso/compat_gettimeofday.h> +#else +#include <asm/vdso/gettimeofday.h> +#endif /* ENABLE_COMPAT_VDSO */ diff --git a/include/vdso/helpers.h b/include/vdso/helpers.h index 9a2af9fca45e..cb7a456323e3 100644 --- a/include/vdso/helpers.h +++ b/include/vdso/helpers.h @@ -6,6 +6,8 @@ #include <vdso/datapage.h> +#include <asm/barrier.h> + static __always_inline u32 vdso_read_begin(const struct vdso_data *vd) { u32 seq; diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c index ce2f69552003..8c1786ae59d8 100644 --- a/lib/vdso/gettimeofday.c +++ b/lib/vdso/gettimeofday.c @@ -3,6 +3,7 @@ * Generic userspace implementations of gettimeofday() and similar. */ #include <vdso/datapage.h> +#include <vdso/gettimeofday.h> #include <vdso/helpers.h> #ifndef vdso_calc_delta -- Catalin
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