On 7/7/16, 3:09 PM, "Laurent Vivier" <laur...@vivier.eu> wrote:
> > >Le 07/07/2016 à 21:04, Wirth, Allan a écrit : >> >> >> 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. > >If I provide a patch, could you test it for your test case? > >Thanks, >Laurent Definitely I would be happy to. I would be very grateful if you did. Thanks, Allan
