On 2014/4/24 11:28 PM, Catalin Marinas wrote: > On Thu, Apr 24, 2014 at 09:55:25AM +0100, Chung-Lin Tang wrote: >> On 2014/4/24 02:26 PM, Chung-Lin Tang wrote: >>> On 2014/4/24 上午 02:15, Pinski, Andrew wrote: >>>> >>>>>> On Apr 23, 2014, at 10:59 AM, "Chung-Lin Tang" <cltang@xxxxxxxxxxxxxxxx> wrote: >>>>>> >>>>>>>> On 2014/4/22 07:20 PM, Ley Foon Tan wrote: >>>>>>>> On Tue, Apr 22, 2014 at 6:56 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote: >>>>>>>>>>>> On Tuesday 22 April 2014 18:37:11 Ley Foon Tan wrote: >>>>>>>>>>>>>>>> Hi Arnd and Peter Anvin, >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Other than 64-bit time_t, clock_t and suseconds_t, can you confirm >>>>>>>>>>>>>>>> that we don't need to have 64 bit off_t? See detail in link below. >>>>>>>>>>>>>>>> I can submit the patches for 64-bit time changes >>>>>>>>>>>>>>>> (include/asm-generic/posix_types.h and other archs) if everyone is >>>>>>>>>>>>>>>> agreed on this. >>>>>>>>>>>> >>>>>>>>>>>> Yes. >>>>>>>> Okay, will doing that. >>>>>> >>>>>> I believe that arm64 ILP32 will also be affected. What is the status of >>>>>> this configuration? Has the glibc/kernel ABI been finalized? >>>> Not yet. I am still working out the signal handling part. But we >>>> already agreed on 64bit time_t, clock_t, and suseconds_t. And we >>>> agreed to a 64bit offset_t too. >>>> >>>> On a related note suseconds in the timespec in posix is defined to >>>> be long. So it would nice if the kernel ignores the upper 32bits so >>>> we (glibc developers) can fix this for new targets including x32 >>>> and arm64/ilp32. >>> >>> Hmm, but that means for purely 32-bit architectures like nios2, which >>> unlike x86_64 or arm64, never has a 64-bit mode, suseconds_t as a 64-bit >>> type in the kernel is simply wasted. >> >> The more I think of this, the more I feel that suseconds_t should jsut >> be 'long', not strictly 64-bitified. An ILP32 sub-mode in a 64-bit >> kernel should be using compat_* code paths, something like a >> COMPAT_USE_32BIT_SUSECONDS case. > > ILP32 mode should use LP64 syscalls as much as possible and that's the > aim with arm64 as well (of course, we still have a few that wouldn't be > possible and we route them via compat). > > But here if time_t is 64-bit while susecconds_t is 32-bit, the compat > code wouldn't help. Why not? You can define the arm64 'struct compat_timeval' with suseconds_t as s32, and add the 32<-->64 case in the compat_get/put_timeval path, triggered when the process is ILP32 (test wrapped in the above hypothetical COMPAT_USE_32BIT_SUSECONDS macro). Similar to how x32 does COMPAT_USE_64BIT_TIME. Chung-Lin -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
