On Tue, Apr 21, 2020 at 8:56 AM Christophe Leroy <christophe.le...@c-s.fr> wrote: > Le 20/04/2020 à 21:57, Arnd Bergmann a écrit : > > Yes that was one of the objective, be able to add that as a second step. > First objective was adding the missing clocks and increasing > maintainability. > > I can add a patch for that now, it looks easy, but how do I test it ? > vdsotest from Nathan doesn't seem to test that.
I wasn't aware of vdsotest, but I suppose it should be fixed in there as well. It's only one extra call that is supposed to be available on all 32-bit architectures. The other thing to try is musl libc 1.2, or any distro based on it. https://distfiles.adelielinux.org/adelie/1.0/iso/rc1/ has a ppc32 image file. I think this is all you should need to do to enable vdso in musl: --- a/arch/powerpc/syscall_arch.h +++ b/arch/powerpc/syscall_arch.h @@ -92,3 +92,9 @@ static inline long __syscall6(long n, long a, long b, long c, long d, long e, lo #define SO_RCVTIMEO_OLD 18 #define SO_SNDTIMEO_OLD 19 + +#define VDSO_USEFUL +#define VDSO_CGT32_SYM "__vdso_clock_gettime" +#define VDSO_CGT32_VER "LINUX_2.6" +#define VDSO_CGT_SYM "__vdso_clock_gettime64" +#define VDSO_CGT_VER "LINUX_2.6" At the moment, the vdso is just disabled for powerpc because there is no __vdso_clock_gettime64 definition in the kernel. > > Without it, any 32-bit user space has to go through the system call > > for time()/getttimeofday()/clock_gettime() when built with a > > modern libc. > > > > How modern ? I have glibc 2.28, the only symbols it seems to know are > (extracted with 'strings') : > > __vdso_clock_gettime > __vdso_time > __vdso_get_tbfreq > __vdso_getcpu > __vdso_clock_getres > __vdso_sigtramp32 > __vdso_sigtramp_rt32 > __vdso_gettimeofday Mainline glibc still doesn't have it, I don't know when it will, presumably either the coming 2.32 release, or 2.33. There is a tree at https://github.com/lmajewski/y2038_glibc/commits/y2038_edge that has the necessary changes, and it is slowly getting merged upstream. Arnd
