On 29/08/2019 16:25, Andy Lutomirski wrote:

On Thu, Aug 29, 2019 at 4:19 AM Vincenzo Frascino
[off-list ref] wrote:

quoted

VDSO_HAS_32BIT_FALLBACK was introduced to address a regression which
caused seccomp to deny access to the applications to clock_gettime64()
and clock_getres64() because they are not enabled in the existing
filters.

The purpose of VDSO_HAS_32BIT_FALLBACK was to simplify the conditional
implementation of __cvdso_clock_get*time32() variants.

Now that all the architectures that support the generic vDSO library
have been converted to support the 32 bit fallbacks the conditional
can be removed.

Cc: Thomas Gleixner <redacted>
CC: Andy Lutomirski <luto@kernel.org>
References: c60a32ea4f45 ("lib/vdso/32: Provide legacy syscall fallbacks")
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
---
 lib/vdso/gettimeofday.c | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c
index a86e89e6dedc..2c4b311c226d 100644
--- a/lib/vdso/gettimeofday.c
+++ b/lib/vdso/gettimeofday.c

@@ -126,13 +126,8 @@ __cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res)

        ret = __cvdso_clock_gettime_common(clock, &ts);

-#ifdef VDSO_HAS_32BIT_FALLBACK
        if (unlikely(ret))
                return clock_gettime32_fallback(clock, res);
-#else
-       if (unlikely(ret))
-               ret = clock_gettime_fallback(clock, &ts);
-#endif

        if (likely(!ret)) {
                res->tv_sec = ts.tv_sec;

I think you could have a little follow-up patch to remove the if
statement -- by the time you get here, it's guaranteed that ret == 0.

Thanks, I will add a new patch that does that to v2 (with a comment).

--Andy

-- 
Regards,
Vincenzo

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