linux-kernel - Re: [PATCH 52/58] x86: vdso: Add prototypes for __vdso

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Date:	Mon, 19 Nov 2012 14:44:05 -0800
From:	Andy Lutomirski <luto@...capital.net>
To:	Josh Triplett <josh@...htriplett.org>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
	John Stultz <john.stultz@...aro.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 52/58] x86: vdso: Add prototypes for __vdso_* functions

On Mon, Nov 19, 2012 at 12:37 PM, Josh Triplett <josh@...htriplett.org> wrote:
> On Mon, Nov 19, 2012 at 12:04:23PM -0800, Andy Lutomirski wrote:
>> On Sun, Nov 18, 2012 at 9:28 PM, Josh Triplett <josh@...htriplett.org> wrote:
>> > arch/x86/vdso/vclock_gettime.c and arch/x86/vdso/vgetcpu.c define
>> > several functions prefixed by __vdso_*, used in the alias definitions
>> > for the actual vdso symbols calls.  Add prototypes of these functions
>> > right before their definitions, to satisfy gcc (-Wmissing-prototypes)
>> > and Sparse (-Wdecl).
>> >
>> > arch/x86/vdso/vclock_gettime.c:161:45: warning: no previous prototype for ‘__vdso_clock_gettime’ [-Wmissing-prototypes]
>> > arch/x86/vdso/vclock_gettime.c:185:45: warning: no previous prototype for ‘__vdso_gettimeofday’ [-Wmissing-prototypes]
>> > arch/x86/vdso/vclock_gettime.c:213:48: warning: no previous prototype for ‘__vdso_time’ [-Wmissing-prototypes]
>> > arch/x86/vdso/vgetcpu.c:16:1: warning: no previous prototype for ‘__vdso_getcpu’ [-Wmissing-prototypes]
>> >
>> > Signed-off-by: Josh Triplett <josh@...htriplett.org>
>> > ---
>> >  arch/x86/vdso/vclock_gettime.c |    3 +++
>> >  arch/x86/vdso/vgetcpu.c        |    2 ++
>> >  2 files changed, 5 insertions(+)
>> >
>> > diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
>> > index 4df6c37..bc8b276 100644
>> > --- a/arch/x86/vdso/vclock_gettime.c
>> > +++ b/arch/x86/vdso/vclock_gettime.c
>> > @@ -158,6 +158,7 @@ notrace static int do_monotonic_coarse(struct timespec *ts)
>> >         return 0;
>> >  }
>> >
>> > +int __vdso_clock_gettime(clockid_t clock, struct timespec *ts);
>> >  notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
>> >  {
>> >         int ret = VCLOCK_NONE;
>> > @@ -182,6 +183,7 @@ notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
>> >  int clock_gettime(clockid_t, struct timespec *)
>> >         __attribute__((weak, alias("__vdso_clock_gettime")));
>> >
>> > +int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz);
>> >  notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
>> >  {
>> >         long ret = VCLOCK_NONE;
>> > @@ -210,6 +212,7 @@ int gettimeofday(struct timeval *, struct timezone *)
>> >   * This will break when the xtime seconds get inaccurate, but that is
>> >   * unlikely
>> >   */
>> > +time_t __vdso_time(time_t *t);
>> >  notrace time_t __vdso_time(time_t *t)
>> >  {
>> >         /* This is atomic on x86_64 so we don't need any locks. */
>> > diff --git a/arch/x86/vdso/vgetcpu.c b/arch/x86/vdso/vgetcpu.c
>> > index 5463ad5..b55350f 100644
>> > --- a/arch/x86/vdso/vgetcpu.c
>> > +++ b/arch/x86/vdso/vgetcpu.c
>> > @@ -12,6 +12,8 @@
>> >  #include <asm/vsyscall.h>
>> >  #include <asm/vgtod.h>
>> >
>> > +long __vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused);
>> > +
>> >  notrace long
>> >  __vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
>> >  {
>> > --
>> > 1.7.10.4
>> >
>>
>> Acked-by: Andy Lutomirski <luto@...capital.net>
>>
>> In theory, this could go in arch/x86/include/uapi/asm/vdso.h.  No one
>> cares, I suspect, since there exactly two non-test-case users that I
>> know of.
>
> If you think it makes sense to put the VDSO prototypes in that UAPI
> header, I could prepare an alternate patch that does so.

That header doesn't actually exist.  Feel free to create it if you're
feeling ambitious :)

--Andy
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