Date: Fri, 8 Aug 2008 14:27:42 -0400 From: John Baldwin <jhb@freebsd.org> To: Kostik Belousov <kostikbel@gmail.com> Cc: Stanislav Sedov <stas@freebsd.org>, cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/share/man/man4 Makefile cpuctl.4 src/sys/amd64/amd64 support.S src/sys/amd64/conf NOTES src/sys/amd64/include cpufunc.h specialreg.h src/sys/conf files.amd64 files.i386 src/sys/dev/cpuctl cpuctl.c ... Message-ID: <200808081427.42536.jhb@freebsd.org> In-Reply-To: <20080808181052.GF97161@deviant.kiev.zoral.com.ua> References: <200808081631.m78GVG9i088754@repoman.freebsd.org> <200808081251.17686.jhb@freebsd.org> <20080808181052.GF97161@deviant.kiev.zoral.com.ua>
next in thread | previous in thread | raw e-mail | index | archive | help
On Friday 08 August 2008 02:10:52 pm Kostik Belousov wrote: > On Fri, Aug 08, 2008 at 12:51:17PM -0400, John Baldwin wrote: > > On Friday 08 August 2008 12:26:53 pm Stanislav Sedov wrote: > > > stas 2008-08-08 16:26:53 UTC > > > > > > FreeBSD src repository > > > > > > Modified files: > > > share/man/man4 Makefile > > > sys/amd64/amd64 support.S > > > sys/amd64/conf NOTES > > > sys/amd64/include cpufunc.h specialreg.h > > > sys/conf files.amd64 files.i386 > > > sys/i386/conf NOTES > > > sys/i386/i386 support.s > > > sys/i386/include cpufunc.h specialreg.h > > > sys/modules Makefile > > > sys/sys priv.h > > > usr.sbin Makefile > > > Added files: > > > share/man/man4 cpuctl.4 > > > sys/dev/cpuctl cpuctl.c > > > sys/modules/cpuctl Makefile > > > sys/sys cpuctl.h > > > usr.sbin/cpucontrol Makefile amd.c amd.h cpucontrol.8 > > > cpucontrol.c cpucontrol.h intel.c intel.h > > > Log: > > > SVN rev 181430 on 2008-08-08 16:26:53Z by stas > > > > > > - Add cpuctl(4) pseudo-device driver to provide access to some low-level > > > features of CPUs like reading/writing machine-specific registers, > > > retrieving cpuid data, and updating microcode. > > > - Add cpucontrol(8) utility, that provides userland access to > > > the features of cpuctl(4). > > > - Add subsequent manpages. > > > > > > The cpuctl(4) device operates as follows. The pseudo-device node cpuctlX > > > is created for each cpu present in the systems. The pseudo-device minor > > > number corresponds to the cpu number in the system. The cpuctl(4) pseudo- > > > device allows a number of ioctl to be preformed, namely RDMSR/WRMSR/CPUID > > > and UPDATE. The first pair alows the caller to read/write machine-specific > > > registers from the correspondent CPU. cpuid data could be retrieved using > > > the CPUID call, and microcode updates are applied via UPDATE. > > > > > > The permissions are inforced based on the pseudo-device file permissions. > > > RDMSR/CPUID will be allowed when the caller has read access to the device > > > node, while WRMSR/UPDATE will be granted only when the node is opened > > > for writing. There're also a number of priv(9) checks. > > > > > > The cpucontrol(8) utility is intened to provide userland access to > > > the cpuctl(4) device features. The utility also allows one to apply > > > cpu microcode updates. > > > > > > Currently only Intel and AMD cpus are supported and were tested. > > > > Note that cpuid isn't a privileged instruction, so I'm not sure it's really > > worth having an ioctl for that particular case. > > It was discussed when patch was reviewed on current@. The ioctl allows > to get cpuid information for specific processor, as opposed to some > random core curthread happens to run ATM. You can achieve that now with cpuset. :) (See my ping-pong test program recently which used cpuid to fetch the APIC ID to test for ping-ponging in the scheduler.) -- John Baldwin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200808081427.42536.jhb>