On Tuesday 03 May 2016 10:00:45 Catalin Marinas wrote:

On Fri, Apr 29, 2016 at 07:30:19PM +0200, Arnd Bergmann wrote:

quoted

On Friday 29 April 2016 17:01:55 Catalin Marinas wrote:

quoted

On Wed, Apr 06, 2016 at 01:08:46AM +0300, Yury Norov wrote:

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ILP32 VDSO exports next symbols:
 __kernel_rt_sigreturn;
 __kernel_gettimeofday;
 __kernel_clock_gettime;
 __kernel_clock_getres;

[...]

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+$(obj)/gettimeofday-ilp32.o: $(src)/../vdso/gettimeofday.S
+ $(call if_changed_dep,vdso-ilp32as)

Are struct timeval and timespec the same between ILP32 and LP64? For
example, __kernel_gettimeofday() assumes TVAL_TV_SEC offset defined in
asm-offsets.c based on the LP64 timeval.

No, ilp32 uses the generic 32-bit data structures, which have a 32-bit
time_t. I guess that means it can work for little-endian but not
big-endian, right?

I don't think it works for little-endian either. The LP64 struct timeval
is 16 bytes while the ILP32 one is 8 bytes. The VDSO gettimeofday is
storing 16 bytes (stp x10, x11, [x0, #TVAL_TV_SEC])

You are right. Yury asked pointed out the same thing on IRC as well.
Using the 64-bit gettimeofday() will put the right number in the
.tv_sec member on little-endian, but will write zeroes to tv_nsec
and corrupt the memory following it.

Yury also tried it out and noticed that for a (so far) unknown reason,
the vdso gets never used by his glibc build, so it has not triggered
any test case failures.

	Arnd