On 7/7/16, 3:02 PM, "Laurent Vivier" <laur...@vivier.eu> wrote:
> > >Le 07/07/2016 à 20:49, Riku Voipio a écrit : >> On Sat, Jul 02, 2016 at 09:12:09PM +0100, Peter Maydell wrote: >>> On 2 July 2016 at 17:41, Laurent Vivier <laur...@vivier.eu> wrote: >>>> Sadly, this can't work: >>>> >>>> sparc/sparc64/cris use sys_select for NR_select AND NR_newselect. >>> >>>> Not sure all is correct, but it's what I've found: >>>> >>>> | __NR_select | __NR__newselect >>>> ------------+----------------+-----------------+ >>>> arm | sys_old_select | sys_select | >>>> ------------+----------------+-----------------+ >>>> aarch64 | sys_select | - | >>>> ------------+----------------+-----------------+ >>>> alpha | sys_select | - | >>>> ------------+----------------+-----------------+ >>>> cris | sys_select | sys_select | >>>> ------------+----------------+-----------------+ >>>> m68k | sys_old_select | sys_select | >>>> ------------+----------------+-----------------+ >>>> microblaze | sys_old_select | sys_select | >>>> ------------+----------------+-----------------+ >>>> mips | sys_old_select | sys_select | >>>> ------------+----------------+-----------------+ >>>> mips64 | sys_select | - | >>>> ------------+----------------+-----------------+ >>>> openrisc | sys_select | - | >>>> ------------+----------------+-----------------+ >>>> ppc | sys_old_select | sys_select | >>>> ------------+----------------+-----------------+ >>>> s390x | sys_select | - | >>>> ------------+----------------+-----------------+ >>>> sh4 | sys_old_select | sys_select | >>>> ------------+----------------+-----------------+ >>>> sparc | sys_select | sys_select | >>>> ------------+----------------+-----------------+ >>>> sparc64 | sys_select | sys_select | >>>> ------------+----------------+-----------------+ >>>> tilegx | sys_select | - | >>>> ------------+----------------+-----------------+ >>>> unicore32 | sys_select | - | >>>> ------------+----------------+-----------------+ >>>> x86_64 | sys_select | - | >>>> ------------+----------------+-----------------+ >>>> i386 | sys_old_select | sys_select | >>>> ------------+----------------+-----------------+ >>> >>> Hmm. Looking at current Linux git master, I get >>> slightly different results. The only architectures which >>> define __ARCH_WANT_SYS_OLD_SELECT are: >>> arm, m68k, mn10300, x86 >>> and no others use sys_old_select. >>> >>> So I think we have the following behaviours: >>> >>> (1) Define neither NR_select nor NR__newselect >>> (and use pselect6 syscall for select): >>> aarch64, openrisc, tilegx, unicore32, presumably any future arch >>> >>> (2) only define NR__newselect, it is new select: >>> mips, mips64, sh, s390 >>> >>> (3) Only define NR_select, want that to be new select: >>> alpha, x86_64, s390x >>> >>> (4) NR__newselect is new select, NR_select is old_select: >>> i386, m68k, arm if kernel is not CONFIG_AEABI >>> >>> (5) NR__newselect is new select, NR_select is defined but >>> if called returns ENOSYS: >>> microblaze, arm if CONFIG_AEABI, ppc64 >>> >>> (6) NR__newselect is new select, NR_select is a bonkers custom >>> thing that tries to autodetect the calling convention: >>> http://lxr.free-electrons.com/source/arch/powerpc/kernel/syscalls.c#L86 >>> ppc32 (but only native 32-bit; 32-bit compat support >>> on a ppc64 kernel is category 5, so I vote for ignoring >>> this weirdness and calling ppc category 5) >>> >>> (7) NR_select and NR__newselect are different numbers >>> but both are new select: >>> cris, sparc, sparc64 >>> >>> which is a pretty confusing mess, but I think it equates to: >>> (0) if defined, NR__newselect is always new select >>> (1) if NR_select is defined, the choices are: >>> (a) NR_select is old_select: >>> i386, m68k, arm >>> (b) NR_select is defined but should ENOSYS: >>> microblaze, ppc >>> (c) NR_select defined and is new select: >>> everything else (alpha, x86-64, s390x, cris, sparc, sparc64) >>> >>> and I think we should handle that by having the code in syscall.c >>> be something like: >>> >>> #ifdef TARGET_NR_select >>> case TARGET_NR_select: >>> #if defined(TARGET_WANT_NI_OLD_SELECT) >>> /* some architectures used to have old_select here >>> * but now ENOSYS it. >>> */ >>> ret = -TARGET_ENOSYS; >>> break; >>> #elif defined(TARGET_WANT_OLD_SYS_SELECT) >>> /* code for old select here; maybe factored out to >>> * its own function: ret = do_old_select() ? >>> */ >>> #else >>> /* select is new style select */ >>> ret = do_select(...); >>> #endif >>> #endif >> >> I agree, this seems to be the best way to fix select properly. > >Ok, if no one is already working on that, I'm going to send a patch >according to Peter's comments. > >Laurent I was hoping to, but I do not think that I will get around to it anytime soon. -Allan
