Messages in this thread | | | Date | Tue, 06 Nov 2018 16:08:12 -0800 (PST) | Subject | Re: [PATCH] riscv: add asm/unistd.h UAPI header | From | Palmer Dabbelt <> |
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On Mon, 05 Nov 2018 12:56:15 PST (-0800), Arnd Bergmann wrote: > On 11/5/18, David Abdurachmanov <david.abdurachmanov@gmail.com> wrote: >> Marcin Juszkiewicz reported issues while generating syscall table for riscv >> using 4.20-rc1. The patch refactors our unistd.h files to match some other >> architectures. >> >> - Add asm/unistd.h UAPI header, which has __ARCH_WANT_NEW_STAT >> - Remove asm/syscalls.h UAPI header and merge to asm/unistd.h >> - Adjust kernel asm/unistd.h >> >> So now asm/unistd.h UAPI header should show all syscalls for riscv. >> >> Before this, Makefile simply put `#include <asm-generic/unistd.h>` into >> generated asm/unistd.h UAPI header thus user didn't see: >> >> - __NR_riscv_flush_icache >> - __NR_newfstatat >> - __NR_fstat >> >> which are supported by riscv kernel. >> >> Signed-off-by: David Abdurachmanov <david.abdurachmanov@gmail.com> >> Cc: Arnd Bergmann <arnd@arndb.de> >> Cc: Marcin Juszkiewicz <marcin.juszkiewicz@linaro.org> >> Cc: Guenter Roeck <linux@roeck-us.net> > > Thanks for addressing this, your patch correctly fixes riscv64, and > I should have noticed the mistake when I originally merged the > broken patch. > > However, looking closer I found another problem with the original > patch that your fix does not address: > > __ARCH_WANT_NEW_STAT should only be set on 64-bit > architectures. > > For a 32-bit architecture, we only want __ARCH_WANT_STAT64 if > any. For 64-bit architectures with compat mode, we still need to > set __ARCH_WANT_STAT64 from the non-uapi file so we get > the syscall implementation. > > If we don't care about the riscv32 ABI changing yet, we can > decide to leave out __ARCH_WANT_STAT64 here, and require > glibc to implement it using statx() like any new architecture. > stat64 is not y2038 safe, and statx replaces it because of that.
Thanks for pointing this out. A while ago we decided the rv32 ABI was "slushy": it can change if it has a good reason to. Right now the only planned changes are the y2038 changes, which I consider this a part of. For some reason I thought we'd already done this, but since we haven't then I think it should go in sooner rather than later -- that will help the glibc guys get everything lined up.
The target is still the next glibc release (Feb 1st) for a stable RV32I ABI. That's progressing well, with one last blocking issue related to some of our floating-point emulation routines before we can submit the port. This should give us ample time to line up the ABIs correctly so everything works.
So I think the correct answer here is to drop __ARCH_WANT_STAT64 from RISC-V.
>> Fixes: 67314ec7b025 > > That line should be formatted as > > Fixes: 67314ec7b025 ("RISC-V: Request newstat syscalls")
Yep, and I have
[pretty] fixes = Fixes: %h (\"%s\")
to make that slightly easier for me to remember :).
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