Date: Mon, 10 Feb 2020 21:15:58 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: John Baldwin <jhb@freebsd.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r357695 - in head: sys/kern sys/sys usr.bin/procstat Message-ID: <20200210191558.GX4808@kib.kiev.ua> In-Reply-To: <d04de408-be97-9405-b77d-d5f4cfdb248d@FreeBSD.org> References: <202002091210.019CAciS006085@repo.freebsd.org> <d04de408-be97-9405-b77d-d5f4cfdb248d@FreeBSD.org>
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On Mon, Feb 10, 2020 at 10:11:43AM -0800, John Baldwin wrote: > On 2/9/20 4:10 AM, Konstantin Belousov wrote: > > Author: kib > > Date: Sun Feb 9 12:10:37 2020 > > New Revision: 357695 > > URL: https://svnweb.freebsd.org/changeset/base/357695 > > > > Log: > > Add AT_BSDFLAGS auxv entry. > > > > The intent is to provide bsd-specific flags relevant to interpreter > > and C runtime. I did not want to reuse AT_FLAGS which is common ELF > > auxv entry. > > > > Use bsdflags to report kernel support for sigfastblock(2). This > > allows rtld and libthr to safely infer the syscall presence without > > SIGSYS. The tunable kern.elf{32,64}.sigfastblock blocks reporting. > > > > Tested by: pho > > Disscussed with: cem, emaste, jilles > > Sponsored by: The FreeBSD Foundation > > Differential revision: https://reviews.freebsd.org/D12773 > > I find adding a new auxv type curious. The MIPS ABI doc says that > "bits under the 0xff000000 mask are reserved for system semantics". > The powerpc and x86-64 docs don't define any bits at all. In > practice I think we are free to use AT_FLAGS however we wish as no > use cases of "standard" bits have arisen since AT_FLAGS was first > defined. So you would prefer to have me used AT_FLAGS for sigfastblock indicator ? I am feeling uncomfortable doing that. My reasoning, to reformulate it from what I wrote in the commit message, is to not pollute neither compilation nor ABI namespace for bsd-specific flags. AT_FLAGS was not touched by anybody and I do not want to open it for use, since ABI group my finally find some use for it.
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