Re: [PATCH 15/22] arch: vdso: consolidate gettime prototypes

Christophe Leroy
2023-11-08T18:31:23Z

Hi Arnd,

Le 08/11/2023 à 13:58, Arnd Bergmann a écrit :
> From: Arnd Bergmann <arnd@arndb.de>
>
> The VDSO functions are defined as globals in the kernel sources but intended
> to be called from userspace, so there is no need to declare them in a kernel
> side header.
>
> Without a prototype, this now causes warnings such as
>
> arch/mips/vdso/vgettimeofday.c:14:5: error: no previous prototype for '__vdso_clock_gettime' [-Werror=missing-prototypes]
> arch/mips/vdso/vgettimeofday.c:28:5: error: no previous prototype for '__vdso_gettimeofday' [-Werror=missing-prototypes]
> arch/mips/vdso/vgettimeofday.c:36:5: error: no previous prototype for '__vdso_clock_getres' [-Werror=missing-prototypes]
> arch/mips/vdso/vgettimeofday.c:42:5: error: no previous prototype for '__vdso_clock_gettime64' [-Werror=missing-prototypes]
> arch/sparc/vdso/vclock_gettime.c:254:1: error: no previous prototype for '__vdso_clock_gettime' [-Werror=missing-prototypes]
> arch/sparc/vdso/vclock_gettime.c:282:1: error: no previous prototype for '__vdso_clock_gettime_stick' [-Werror=missing-prototypes]
> arch/sparc/vdso/vclock_gettime.c:307:1: error: no previous prototype for '__vdso_gettimeofday' [-Werror=missing-prototypes]
> arch/sparc/vdso/vclock_gettime.c:343:1: error: no previous prototype for '__vdso_gettimeofday_stick' [-Werror=missing-prototypes]
>
> Most architectures have already added workarounds for these by adding
> declarations somewhere, but since these are all compatible, we should
> really just have one copy, with an #ifdef check for the 32-bit vs
> 64-bit variant and use that everywhere.
>
> Unfortunately, the sparc version is currently incompatible since
> that never added support for __vdso_clock_gettime64() in 32-bit
> userland. For the moment, I'm leaving this one out, as I can't
> easily test it and it requires a larger rework.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> arch/arm/include/asm/vdso.h | 5 -----
> arch/arm/vdso/vgettimeofday.c | 1 +
> arch/arm64/kernel/vdso32/vgettimeofday.c | 1 +
> arch/csky/kernel/vdso/vgettimeofday.c | 11 +----------
> arch/loongarch/vdso/vgettimeofday.c | 7 +------
> arch/mips/vdso/vgettimeofday.c | 1 +
> arch/riscv/kernel/vdso/vgettimeofday.c | 7 +------
> arch/x86/entry/vdso/vclock_gettime.c | 10 +---------
> arch/x86/include/asm/vdso/gettimeofday.h | 2 --
> arch/x86/um/vdso/um_vdso.c | 1 +
> include/vdso/gettime.h | 23 +++++++++++++++++++++++
> 11 files changed, 31 insertions(+), 38 deletions(-)
> create mode 100644 include/vdso/gettime.h

powerpc has functions doing more or less the same, they are called
__c_kernel_clock_gettime() and alike with their prototypes siting in
arch/powerpc/include/asm/vdso/gettimeofday.h

Should those prototypes be moved to include/vdso/gettime.h too and
eventually renamed, or are they considered too powerpc specific ?

Christophe