Date: Tue, 15 Dec 2009 20:04:59 +0100 From: Patrick Lamaiziere <patfbsd@davenulle.org> To: bug-followup@freebsd.org Cc: freebsd-amd64@FreeBSD.org Subject: Re: amd64/135014: [padlock] Using padlock(4) in 8-current triggers "fpudna in kernel mode!" warnings Message-ID: <20091215200459.3dbe84eb@baby-jane.lamaiziere.net> In-Reply-To: <20091216005926.T34815@delplex.bde.org> References: <200912150035.nBF0ZsLi088804@freefall.freebsd.org> <20091216005926.T34815@delplex.bde.org>
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Le Wed, 16 Dec 2009 01:35:07 +1100 (EST), Bruce Evans <brde@optusnet.com.au> a =E9crit : > [This probably won't make it into the followup, since gnats still > doesn't generate useful followup addresses and I didn't tyy to edit > the headers.] >=20 > > Synopsis: [padlock] Using padlock(4) in 8-current triggers "fpudna > > in kernel mode!" warnings >=20 > > By request of Michael Moll in followup, reclassify this as an amd64 > > bug. His theory is that the floating-point registers may not be > > being handled correctly in the kernel. >=20 > This seems to be a bug in padlock(4). Apparently the inline asm that > it uses requires the FPU. But use of the FPU in the kernel is not > supported. (except the obsolete i586 copy optimizations). According to the Linux code, padlock does not use the FPU but can generate a DNA fault: http://fxr.watson.org/fxr/source/drivers/crypto/padlock-aes.c?v=3Dlinux-2.6= #L182 =20 They use a irq_ts_save() / restore operation between padlock intruction. I don't know if there are similar things into the FreeBSD kernel: http://fxr.watson.org/fxr/source/drivers/crypto/padlock-aes.c?v=3Dlinux-2.6= #L296 See also this thread: http://lkml.indiana.edu/hypermail/linux/kernel/0808.1/0306.html HTH, regards.
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