From: David Laight <david.laight.linux@gmail.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Maciej W. Rozycki" <macro@orcam.me.uk>,
Christian Ludloff <ludloff@gmail.com>,
Dave Hansen <dave.hansen@intel.com>,
Richard Weinberger <richard@nod.at>,
Sohil Mehta <sohil.mehta@intel.com>,
"Ahmed S. Darwish" <darwi@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
x86@kernel.org, Thomas Gleixner <tglx@kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Tony Luck <tony.luck@intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/3] x86/cpu/intel: Simplify F00F bug notice using pr_notice_once()
Date: Mon, 1 Jun 2026 22:45:33 +0100 [thread overview]
Message-ID: <20260601224533.6dc1b37b@pumpkin> (raw)
In-Reply-To: <6C32834F-6EC5-4A36-A6A6-132C2D52E45A@zytor.com>
On Mon, 01 Jun 2026 07:43:32 -0700
"H. Peter Anvin" <hpa@zytor.com> wrote:
> On May 27, 2026 9:14:10 AM PDT, "Maciej W. Rozycki" <macro@orcam.me.uk> wrote:
> >On Wed, 27 May 2026, H. Peter Anvin wrote:
> >
> >> >> If full precision is enabled there are a whole lot of horrid corner cases.
> >> >> Mostly due to correctly generating the FP signals when the 80bit return
> >> >> value from a function is written to a 64bit 'double'.
> >> >
> >> > No IEEE quad for `long double' still, not even on 64-bit hw? Weird.
> >>
> >> The ABI was designed in 2003 or so...
> >
> > Hmm, usually it's hardware that gets features first with software to
> >follow. For instance by now the POWER port has gained three `long double'
> >formats in their psABI, all of which can coexist in a single system (I got
> >that covered in the course of the glibc test improvement effort too).
> >
> > Maciej
>
> The x87 psABI does have a __float128 type IIRC.
>
Isn't that the 16bit exponent, 64bit mantissa of the x87 fpu?
It has to aligned so there are 48bits unused.
-- David
next prev parent reply other threads:[~2026-06-01 21:45 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-15 0:24 [PATCH v2 0/3] x86: Fix a F00F bug warning and cleanup surrounding code Sohil Mehta
2026-05-15 0:24 ` [PATCH v2 1/3] x86/cpu/intel: Don't clear X86_BUG_F00F before setting it Sohil Mehta
2026-05-15 19:16 ` Ahmed S. Darwish
2026-05-15 0:24 ` [PATCH v2 2/3] x86/cpu/intel: Simplify F00F bug notice using pr_notice_once() Sohil Mehta
2026-05-15 19:14 ` Ahmed S. Darwish
2026-05-15 22:37 ` Sohil Mehta
2026-05-15 23:09 ` Ahmed S. Darwish
2026-05-15 23:23 ` Dave Hansen
2026-05-18 20:29 ` Sohil Mehta
2026-05-18 21:17 ` Dave Hansen
2026-05-18 21:23 ` H. Peter Anvin
2026-05-21 22:38 ` Maciej W. Rozycki
2026-05-22 6:11 ` Christian Ludloff
2026-05-22 20:27 ` Maciej W. Rozycki
2026-05-25 10:41 ` Maciej W. Rozycki
2026-05-26 20:56 ` Richard Weinberger
2026-05-27 0:25 ` Maciej W. Rozycki
2026-05-26 14:14 ` Dave Hansen
2026-05-26 15:01 ` Maciej W. Rozycki
2026-05-26 15:20 ` David Laight
2026-05-26 17:43 ` Christian Ludloff
2026-05-26 19:15 ` Maciej W. Rozycki
2026-05-26 20:49 ` H. Peter Anvin
2026-05-27 0:29 ` Maciej W. Rozycki
2026-05-27 6:13 ` H. Peter Anvin
2026-05-27 9:09 ` David Laight
2026-05-27 9:23 ` Maciej W. Rozycki
2026-05-27 15:36 ` H. Peter Anvin
2026-05-27 16:14 ` Maciej W. Rozycki
2026-06-01 14:43 ` H. Peter Anvin
2026-06-01 21:45 ` David Laight [this message]
2026-05-15 0:25 ` [PATCH v2 3/3] x86/cpufeature: Remove clear_cpu_bug() Sohil Mehta
2026-05-15 19:16 ` Ahmed S. Darwish
2026-05-15 6:18 ` [PATCH v2 0/3] x86: Fix a F00F bug warning and cleanup surrounding code Richard Weinberger
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