| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <alpine.DEB.2.11.1512081948020.3595@nanos> Date: Tue, 8 Dec 2015 19:48:19 +0100 (CET) From: Thomas Gleixner <tglx@...utronix.de> To: Dave Hansen <dave@...1.net> cc: linux-kernel@...r.kernel.org, linux-mm@...ck.org, x86@...nel.org, dave.hansen@...ux.intel.com Subject: Re: [PATCH 30/34] x86, fpu: allow setting of XSAVE state On Thu, 3 Dec 2015, Dave Hansen wrote: > > From: Dave Hansen <dave.hansen@...ux.intel.com> > > We want to modify the Protection Key rights inside the kernel, so > we need to change PKRU's contents. But, if we do a plain > 'wrpkru', when we return to userspace we might do an XRSTOR and > wipe out the kernel's 'wrpkru'. So, we need to go after PKRU in > the xsave buffer. > > We do this by: > 1. Ensuring that we have the XSAVE registers (fpregs) in the > kernel FPU buffer (fpstate) > 2. Looking up the location of a given state in the buffer > 3. Filling in the stat > 4. Ensuring that the hardware knows that state is present there > (basically that the 'init optimization' is not in place). > 5. Copying the newly-modified state back to the registers if > necessary. > > Signed-off-by: Dave Hansen <dave.hansen@...ux.intel.com> Reviewed-by: Thomas Gleixner <tglx@...utronix.de> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists