On 25/06/24 16:48, Helge Deller wrote: > On 6/24/24 22:31, Adhemerval Zanella Netto wrote: >> >> >> On 21/06/24 16:26, Helge Deller wrote: >>> The upcoming parisc (hppa) v6.11 Linux kernel will include vDSO >>> support for gettimeofday(), clock_gettime() and clock_gettime64() >>> syscalls for 32- and 64-bit userspace. >>> The patch below adds the necessary glue code for glibc. >>> >>> Signed-off-by: Helge Deller <deller@xxxxxx> >>> >>> Changes in v2: >>> - add vsyscalls for 64-bit too >>> >>> diff -up ./sysdeps/unix/sysv/linux/hppa/sysdep.h.org ./sysdeps/unix/sysv/linux/hppa/sysdep.h >>> --- ./sysdeps/unix/sysv/linux/hppa/sysdep.h.org 2024-06-15 20:20:58.992000000 +0000 >>> +++ ./sysdeps/unix/sysv/linux/hppa/sysdep.h 2024-06-21 19:19:02.132000000 +0000 >>> @@ -468,6 +468,18 @@ L(pre_end): ASM_LINE_SEP \ >>> #define CLOB_ARGS_1 CLOB_ARGS_2, "%r25" >>> #define CLOB_ARGS_0 CLOB_ARGS_1, "%r26" >>> >>> +#define VDSO_NAME "LINUX_6.11" >>> +#define VDSO_HASH 182951793 >>> + >>> +#ifdef __LP64__ >>> +# define HAVE_CLOCK_GETTIME_VSYSCALL "__vdso_clock_gettime" >>> +# define HAVE_GETTIMEOFDAY_VSYSCALL "__vdso_gettimeofday" >>> +#else >>> +# define HAVE_CLOCK_GETTIME_VSYSCALL "__vdso_clock_gettime" >>> +# define HAVE_CLOCK_GETTIME64_VSYSCALL "__vdso_clock_gettime64" >>> +# define HAVE_GETTIMEOFDAY_VSYSCALL "__vdso_gettimeofday" >>> +#endif /* __LP64__ */ >>> + >>> #endif /* __ASSEMBLER__ */ >> >> Not sure why you have added the gettimeofday support, currently 32 bits >> it is already routed to to clock_gettime (which will use >> __vdso_clock_gettime64 anyway). > > Yep, you are right. > I actually didn't checked if it's being used but just saw it's defined > for other arches too, so I assumed it to be used. > >> For hppa to actually use, it would require to add a way to call it >> for !USE_IFUNC_GETTIMEOFDAY gettimeofday, which I am not it really be >> an improvement here. > > Yes, that doesn't make sense. > > Looking at the code it seems riscv, sparc, arm, mips and s390 define it > too, without being used. Do you suggest we should remove gettimeofday > vsyscall from hppa again (or just keep like the others even if not being used)? The riscv only added it for CONFIG_64BIT, while old ABIs like arm, sparc, mips, and s390 added before 64 bit time_t landed on 5.1. With current 32 bits ABIs moving to 64 bit time_t userland, there is no much sense in providing a 32 bit gettimeofday, nor I think I adding a gettimeoday64 would make much sense (maybe on really high sensitive workloads that require low-latency timestamping, but clock_gettime would work better anyway). It is highly unlikely that the symbol will ever be used by userland, and I think it only make sense to provide clock_gettime64. The glibc 32 bit time_t clock_gettime routes to clock_gettime64 and it will only fallback to 32 bit vDSO symbol if the 64 bit time_t one is not present.
