linux-toradex.git/arch/x86_64/kernel/process.c, branch v2.6.16.11

[PATCH] i386/x86-64: Fix x87 information leak between processes (CVE-2006-1056)

2006-04-19T05:54:44+00:00

AMD K7/K8 CPUs only save/restore the FOP/FIP/FDP x87 registers in FXSAVE
when an exception is pending.  This means the value leak through context
switches and allow processes to observe some x87 instruction state of
other processes.

This was actually documented by AMD, but nobody recognized it as being
different from Intel before.

The fix first adds an optimization: instead of unconditionally calling
FNCLEX after each FXSAVE test if ES is pending and skip it when not
needed. Then do a x87 load from a kernel variable to clear FOP/FIP/FDP.

This means other processes always will only see a constant value defined
by the kernel in their FP state.

I took some pain to make sure to chose a variable that's already in L1
during context switch to make the overhead of this low.

Also alternative() is used to patch away the new code on CPUs who don't
need it.

Patch for both i386/x86-64.

The problem was discovered originally by Jan Beulich. Richard Brunner
provided the basic code for the workarounds, with contribution from Jan.

This is CVE-2006-1056

Cc: richard.brunner@amd.com
Cc: jbeulich@novell.com
Signed-off-by: Andi Kleen 
Signed-off-by: Greg Kroah-Hartman

[PATCH] x86_64: Don't allow kprobes on __switch_to

2006-02-05T00:43:14+00:00

kprobes cannot deal with the funny calling conventions when it
runs on a different stack when it returns. If someone wants
to instrument context switch they can add a probe to schedule()
instead.

Cc: jkenisto@us.ibm.com, prasanna@in.ibm.com

Signed-off-by: Andi Kleen 
Signed-off-by: Linus Torvalds

[PATCH] amd64: task_stack_page()

2006-01-12T17:08:51+00:00

Signed-off-by: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] amd64: task_pt_regs()

2006-01-12T17:08:51+00:00

Signed-off-by: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] amd64: task_thread_info()

2006-01-12T17:08:51+00:00

Signed-off-by: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] x86_64: Add idle notifiers

2006-01-12T03:04:55+00:00

This adds a new notifier chain that is called with IDLE_START
when a CPU goes idle and IDLE_END when it goes out of idle.
The context can be idle thread or interrupt context.

Since we cannot rely on MONITOR/MWAIT existing the idle
end check currently has to be done in all interrupt
handlers.

They were originally inspired by the similar s390 implementation.

They have a variety of applications:
- They will be needed for CONFIG_NO_IDLE_HZ
- They can be used for oprofile to fix up the missing time
in idle when performance counters don't tick.
- They can be used for better C state management in ACPI
- They could be used for microstate accounting.

This is just infrastructure so far, no users.

Signed-off-by: Andi Kleen 
Signed-off-by: Linus Torvalds

[PATCH] x86_64: Remove enable/disable_hlt

2006-01-12T03:01:12+00:00

Was only used by the floppy driver to work around some ancient
hardware bug that should never occur on any 64bit system.

Signed-off-by: Andi Kleen 
Signed-off-by: Linus Torvalds

[PATCH] cpu hotplug/x86_64: disable interrupt in play_dead

2006-01-06T16:33:39+00:00

With physical CPU hotplug, the CPU is hot removed and it should not receive
any interrupts.  Disabling interrupt is much safer.  This basically is what we
do in ia64 & x86.

Signed-off-by: Shaohua Li 
Cc: Andi Kleen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] kprobes: Fix return probes on sys_execve

2005-11-24T00:08:39+00:00

Fix a bug in kprobes that can cause an Oops or even a crash when a return
probe is installed on one of the following functions: sys_execve,
do_execve, load_*_binary, flush_old_exec, or flush_thread.  The fix is to
remove the call to kprobe_flush_task() in flush_thread().  This fix has
been tested on all architectures for which the return-probes feature has
been implemented (i386, x86_64, ppc64, ia64).  Please apply.

BACKGROUND

Up to now, we have called kprobe_flush_task() under two situations: when a
task exits, and when it execs.  Flushing kretprobe_instances on exit is
correct because (a) do_exit() doesn't return, and (b) one or more
return-probed functions may be active when a task calls do_exit().  Neither
is the case for sys_execve() and its callees.

Initially, the mistaken call to kprobe_flush_task() on exec was harmless
because we put the "real" return address of each active probed function
back in the stack, just to be safe, when we recycled its
kretprobe_instance.  When support for ppc64 and ia64 was added, this safety
measure couldn't be employed, and was eventually dropped even for i386 and
x86_64.  sys_execve() and its callees were informally blacklisted for
return probes until this fix was developed.

Acked-by: Prasanna S Panchamukhi 
Signed-off-by: Jim Keniston 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge x86-64 update from Andi

2005-11-15T03:56:02+00:00