perf tools build broken for RISCV 32 bit

[Emiliano Ingrassia]

Hi Arnd,

thank you for the quick reply and support.

On Mon, Jan 18, 2021 at 12:56:11PM +0100, Arnd Bergmann wrote:
> On Mon, Jan 18, 2021 at 12:35 PM Emiliano Ingrassia
> <ingrassia at epigenesys.com> wrote:
> > |#if __WORDSIZE == 32
> > |/* Workarounds for generic code needing to handle 64-bit time_t.
> > |...
> > |/* Fix sysdeps/nptl/lowlevellock-futex.h.  */
> > |#define __NR_futex              __NR_futex_time64
> >
> > a possible solution to fix the build of perf tool on RISCV 32 bit could
> > be the following patch to file tools/arch/riscv/include/uapi/asm/unistd.h:
> > |+
> > |+#ifndef __NR_futex
> > |+#define __NR_futex __NR_futex_time64
> > |+#endif
> >
> > What do you think about it? Could it be a correct solution?
>
> No, that would be much worse: __NR_futex must only ever point
> to the system call that takes the old timespec argument. If you define
> something like this, it breaks applications that try to do the right thing.
>
>        Arnd

OK, but what should be the right solution for RISCV 32 bit in this case?
Is it a problem in the libc implementation or in RISCV/perf implementation?

Thank you, best regards.

Emiliano