Re: [Qemu-devel] [PATCH v2] linux-user: make getcpu optional

From: Laurent Vivier <laurent@vivier.eu>
To: Mike Frysinger <vapier@gentoo.org>,
	qemu-devel@nongnu.org, Riku Voipio <riku.voipio@iki.fi>
Cc: samuel.thibault@ens-lyon.org
Subject: Re: [Qemu-devel] [PATCH v2] linux-user: make getcpu optional
Date: Sat, 17 Feb 2018 11:35:30 +0100	[thread overview]
Message-ID: <1d0dedd8-4f7e-4b8b-1c69-c581852c95b2@vivier.eu> (raw)
In-Reply-To: <20180217020230.1759-1-vapier@gentoo.org>

Le 17/02/2018 à 03:02, Mike Frysinger a écrit :
> Not all arches implement this, and the kernel doesn't require them to.
> Add ifdef logic to disable it when not available.
> 
> Signed-off-by: Mike Frysinger <vapier@gentoo.org>
> ---
>  linux-user/syscall.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 799c8e2800ea..a9904fac791f 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -290,8 +290,10 @@ _syscall3(int, sys_sched_getaffinity, pid_t, pid, unsigned int, len,
>  #define __NR_sys_sched_setaffinity __NR_sched_setaffinity
>  _syscall3(int, sys_sched_setaffinity, pid_t, pid, unsigned int, len,
>            unsigned long *, user_mask_ptr);
> +#ifdef TARGET_NR_getcpu
>  #define __NR_sys_getcpu __NR_getcpu
>  _syscall3(int, sys_getcpu, unsigned *, cpu, unsigned *, node, void *, tcache);
> +#endif

I didn't find any arch that doesn't have it in linux-user/*/syscall_nr.h
Which arches are you speaking about?

As it can be also undefined for the host arch, you should use:

    #if defined(TARGET_NR_getcpu) && defined(__NR_getcpu)

Thanks,
Laurent