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| Started by | "H. Peter Anvin" <hpa@zytor.com> |
|---|---|
| First post | 2015-09-19 02:10 +0200 |
| Last post | 2015-09-19 02:10 +0200 |
| Articles | 1 — 1 participant |
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Re: [Ksummit-discuss] 2038 Kernel Summit Discussion Fodder "H. Peter Anvin" <hpa@zytor.com> - 2015-09-19 02:10 +0200
| From | "H. Peter Anvin" <hpa@zytor.com> |
|---|---|
| Date | 2015-09-19 02:10 +0200 |
| Subject | Re: [Ksummit-discuss] 2038 Kernel Summit Discussion Fodder |
| Message-ID | <qadT4-1Db-9@gated-at.bofh.it> |
On 08/13/2014 01:06 PM, Arnd Bergmann wrote: > On Wednesday 13 August 2014 03:06:53 Ben Hutchings wrote: >>> On the kernel side, it also adds more complexity, where we have to add >>> even more complex compat support for 64bit systems to handle all the >>> various 32bit applications possible. >> [...] >> >> Didn't we need to do this already to support x32? Have compat ioctls >> involving time been botched? > > AFAICT, every ioctl that involves passing a __kernel_ulong_t or > __kernel_ulong_t is potentially broken on x32, and this includes > everything passing a time_t or timespec. > > The problem is that the libc ioctl() function ends up in the kernel's > compat_ioctl handler, which expects the 32-bit ABI, not the 64-bit ABI. > Most other syscalls in x32 however use the 64-bit ABI. > > It works only for drivers that use the same function for .ioctl and > .compat_ioctl, and that encode the size of the data structure correctly > in the ioctl command code. I assume this is how we will do it for all > 32-bit architectures with 64-bit time_t, but on x32 it also concerns > other types that use __kernel_long_t. > OK, super-late reply. Actually we have by and large dealt with that. Sadly this meant an increase in the number of paths with conditional ABI. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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