Date: Thu, 12 Mar 2015 14:46:53 -0700 From: Nathan Whitehorn <nwhitehorn@freebsd.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r279937 - in head/sys/powerpc: include powerpc Message-ID: <5502094D.5090001@freebsd.org> In-Reply-To: <20150312213530.GT2379@kib.kiev.ua> References: <201503122115.t2CLFdmi026986@svn.freebsd.org> <20150312212234.GS2379@kib.kiev.ua> <55020547.7050102@freebsd.org> <20150312213530.GT2379@kib.kiev.ua>
next in thread | previous in thread | raw e-mail | index | archive | help
On 03/12/15 14:35, Konstantin Belousov wrote: > On Thu, Mar 12, 2015 at 02:29:43PM -0700, Nathan Whitehorn wrote: >> On 03/12/15 14:22, Konstantin Belousov wrote: >>> On Thu, Mar 12, 2015 at 09:15:39PM +0000, Nathan Whitehorn wrote: >>>> Author: nwhitehorn >>>> Date: Thu Mar 12 21:15:38 2015 >>>> New Revision: 279937 >>>> URL: https://svnweb.freebsd.org/changeset/base/279937 >>>> >>>> Log: >>>> Provide VSX context in ucontext(3) API. >>>> >>>> Modified: >>>> head/sys/powerpc/include/ucontext.h >>>> head/sys/powerpc/powerpc/exec_machdep.c >>>> >>>> Modified: head/sys/powerpc/include/ucontext.h >>>> ============================================================================== >>>> --- head/sys/powerpc/include/ucontext.h Thu Mar 12 20:14:48 2015 (r279936) >>>> +++ head/sys/powerpc/include/ucontext.h Thu Mar 12 21:15:38 2015 (r279937) >>>> @@ -46,6 +46,7 @@ typedef struct __mcontext { >>>> uint32_t mc_av[2]; >>>> register_t mc_frame[42]; >>>> uint64_t mc_fpreg[33]; >>>> + uint64_t mc_vsxfpreg[32]; /* low-order half of VSR0-31 */ >>>> } mcontext_t __aligned(16); >>>> >>>> #if defined(_KERNEL) && defined(__powerpc64__) >>>> @@ -60,6 +61,7 @@ typedef struct __mcontext32 { >>>> uint32_t mc_av[2]; >>>> uint32_t mc_frame[42]; >>>> uint64_t mc_fpreg[33]; >>>> + uint64_t mc_vsxfpreg[32]; /* low-order half of VSR0-31 */ >>>> } mcontext32_t __aligned(16); >>>> #endif >>> It looks as if you broken the ABI compatibility by the change. Am I wrong ? >>> >> That is correct. It's a tier-2 platform and -CURRENT, so I'm not sure >> it's worth the compatibility shims. I'm happy to add them if you think >> otherwise. > You are main maintainer of PowerPC port, IMO, so it is your decision. > > Note that 'this is current' argument is not applicable, since the change > also breaks stable/* binaries. > > I do understand the argument of PowerPC being tier 2 architecture, but this > makes me sad. Anyway, it is yours. For x86, I have to introduce > getcontextx(3) mechanism. > This is a good point. I'll try to fix it. Is my understanding of how this works correct? 1. Provide a sysarch() for the extended FPU state. 2. Implement getcontextx() in the C library to fill extra properties if required. 3. Store state for signal trampoline in variable-sized stack area Implementation of (2) seems to rely on having spare members in ucontext, which PowerPC unfortunately does not have. Is there a way around that? -Nathan
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?5502094D.5090001>