Hi Thomas,
On 8/15/19 8:21 PM, Thomas Gleixner wrote:
> On Thu, 15 Aug 2019, Dmitry Safonov wrote:
>> ---
>> arch/Kconfig | 5 +++
>> arch/x86/Kconfig | 1 +
>> arch/x86/entry/vdso/vdso-layout.lds.S | 9 ++++-
>> arch/x86/entry/vdso/vdso2c.c | 3 ++
>> arch/x86/entry/vdso/vma.c | 12 +++++++
>> arch/x86/include/asm/vdso.h | 1 +
>> init/Kconfig | 1 +
>> lib/vdso/gettimeofday.c | 47 +++++++++++++++++++++++++++
>
> This needs to be split into the generic lib/vdso part and then x86 making
> use of it.
Ok
>> +#ifdef CONFIG_TIME_NS
>
> This should be COMPILE_WITH_TIME_NS and not CONFIG_TIME_NS
>
>> +extern u8 timens_page
>> + __attribute__((visibility("hidden")));
>> +
>> +notrace static __always_inline void clk_to_ns(clockid_t clk, struct
>> __kernel_timespec *ts)
>
> This needs notrace because?
Heh, well it's alive from the time it was in arch/x86.
I believe, functions there had it since commit 23adec554a76 ("x86: add
notrace annotations to vsyscall"). Probably, lib/vdso is compiled
without mcount in the Makefile somewhere.
Will drop.
[..]
>> + /*
>> + * The kernel allows to set a negative offset only if the current clock
>> + * value in a namespace is positive, so the result tv_sec can't be
>> + * negative here.
>> + */
>> + ts->tv_nsec += offset64->tv_nsec;
>> + ts->tv_sec += offset64->tv_sec;
>> + if (ts->tv_nsec >= NSEC_PER_SEC) {
>> + ts->tv_nsec -= NSEC_PER_SEC;
>> + ts->tv_sec++;
>> + }
>> + if (ts->tv_nsec < 0) {
>> + ts->tv_nsec += NSEC_PER_SEC;
>> + ts->tv_sec--;
>> + }
>
> That's broken for 32bit user space on 64bit hosts. On LE due to
> misalignment and on BE because 32bit will read always 0.
Ugh, will look into that.
Thanks,
Dmitry
