linux-stable/include
Andrea Arcangeli ffaa8bd6c9 [PATCH] seccomp: tsc disable
I believe at least for seccomp it's worth to turn off the tsc, not just for
HT but for the L2 cache too.  So it's up to you, either you turn it off
completely (which isn't very nice IMHO) or I recommend to apply this below
patch.

This has been tested successfully on x86-64 against current cogito
repository (i686 compiles so I didn't bother testing ;).  People selling
the cpu through cpushare may appreciate this bit for a peace of mind.

There's no way to get any timing info anymore with this applied
(gettimeofday is forbidden of course).  The seccomp environment is
completely deterministic so it can't be allowed to get timing info, it has
to be deterministic so in the future I can enable a computing mode that
does a parallel computing for each task with server side transparent
checkpointing and verification that the output is the same from all the 2/3
seller computers for each task, without the buyer even noticing (for now
the verification is left to the buyer client side and there's no
checkpointing, since that would require more kernel changes to track the
dirty bits but it'll be easy to extend once the basic mode is finished).

Eliminating a cold-cache read of the cr4 global variable will save one
cacheline during the tlb flush while making the code per-cpu-safe at the
same time.  Thanks to Mikael Pettersson for noticing the tlb flush wasn't
per-cpu-safe.

The global tlb flush can run from irq (IPI calling do_flush_tlb_all) but
it'll be transparent to the switch_to code since the IPI won't make any
change to the cr4 contents from the point of view of the interrupted code
and since it's now all per-cpu stuff, it will not race.  So no need to
disable irqs in switch_to slow path.

Signed-off-by: Andrea Arcangeli <andrea@cpushare.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-27 15:11:44 -07:00
..
acpi Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
asm-alpha [PATCH] remove non-DISCONTIG use of pgdat->node_mem_map 2005-06-23 09:45:00 -07:00
asm-arm [PATCH] ARM: 2759/1: Fix IXP4xx debug code (again) 2005-06-27 21:48:48 +01:00
asm-arm26 [PATCH] streamline preempt_count type across archs 2005-06-23 09:45:19 -07:00
asm-cris [PATCH] streamline preempt_count type across archs 2005-06-23 09:45:19 -07:00
asm-frv [PATCH] streamline preempt_count type across archs 2005-06-23 09:45:19 -07:00
asm-generic [PATCH] kexec: vmlinux: fix physical addresses 2005-06-25 16:24:47 -07:00
asm-h8300 [PATCH] streamline preempt_count type across archs 2005-06-23 09:45:19 -07:00
asm-i386 [PATCH] seccomp: tsc disable 2005-06-27 15:11:44 -07:00
asm-ia64 [PATCH] Update cfq io scheduler to time sliced design 2005-06-27 14:33:29 -07:00
asm-m32r [PATCH] streamline preempt_count type across archs 2005-06-23 09:45:19 -07:00
asm-m68k [PATCH] streamline preempt_count type across archs 2005-06-23 09:45:19 -07:00
asm-m68knommu [PATCH] streamline preempt_count type across archs 2005-06-23 09:45:19 -07:00
asm-mips [PATCH] sched: cleanup context switch locking 2005-06-25 16:24:43 -07:00
asm-parisc [PATCH] compat: introduce compat_time_t 2005-06-23 09:45:32 -07:00
asm-ppc [PATCH] ppc32: Bump PMU interrupt priority 2005-06-27 15:11:42 -07:00
asm-ppc64 [PATCH] ppc64: kexec support for ppc64 2005-06-25 16:24:51 -07:00
asm-s390 [PATCH] kexec: s390 support 2005-06-25 16:24:51 -07:00
asm-sh [PATCH] streamline preempt_count type across archs 2005-06-23 09:45:19 -07:00
asm-sh64 [PATCH] streamline preempt_count type across archs 2005-06-23 09:45:19 -07:00
asm-sparc [PATCH] sched: cleanup context switch locking 2005-06-25 16:24:43 -07:00
asm-sparc64 [PATCH] sched: cleanup context switch locking 2005-06-25 16:24:43 -07:00
asm-um [PATCH] uml: add profile_pc for i386 2005-06-25 16:24:36 -07:00
asm-v850 [PATCH] streamline preempt_count type across archs 2005-06-23 09:45:19 -07:00
asm-x86_64 [PATCH] seccomp: tsc disable 2005-06-27 15:11:44 -07:00
asm-xtensa [PATCH] xtensa: Architecture support for Tensilica Xtensa Part 8 2005-06-24 00:05:22 -07:00
linux [PATCH] seccomp: tsc disable 2005-06-27 15:11:44 -07:00
math-emu Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
media [PATCH] v4l: update for SAA7134 cards 2005-06-24 00:06:39 -07:00
mtd Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
net [PATCH] bring over ieee80211.h from mainline 2005-06-27 00:23:54 -04:00
pcmcia [PATCH] yenta TI: turn off interrupts during card power-on #2 2005-06-23 09:45:31 -07:00
rxrpc Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
scsi [PATCH] I2O: Adaptec specific SG_IO access, firmware access through sysfs and 2400A workaround 2005-06-24 00:05:28 -07:00
sound [PATCH] create a kstrdup library function 2005-06-23 09:45:18 -07:00
video [PATCH] Clean-up and bug fix for tdfxfb framebuffer size detection 2005-05-01 08:59:25 -07:00