CPU does not save ss and esp on stack if execution was already in kernel mode
at the time of NMI occurrence. This leads to saving of erractic values for ss
and esp. This patch fixes the issue.
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
o Following patch exports kexec global variable "crash_notes" to user space
through sysfs as kernel attribute in /sys/kernel.
Signed-off-by: Maneesh Soni <maneesh@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In the case of a crash/panic an architecture specific function
machine_crash_shutdown is called. This patch adds to the x86 machine_crash
function the standard kernel code for shutting down apics.
Every line of code added to that function increases the risk that we will call
code after a kernel panic that is not safe.
This patch should not make it to the stable kernel without a being reviewed a
lot more. It is unclear how much a hardned kernel can take when it comes to
misconfigured apics. So since a normal kernel has problems this patch does a
clean shutdown.
It is my expectation this patch will be dropped from future generations of the
kexec work. But for the moment it is a crutch to keep from breaking
everything.
Signed-off-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
After the kernel panics if we wish to generate an entire machine core file it
is very nice to know the register state at the time the machine crashed.
After long discussion it was realized that if you are going to be saving the
information anyway it is reasonable to store the information in a format that
it will be used and recognized in so the register state is stored in the
standard ELF note format.
Signed-off-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
One of the dangers when switching from one kernel to another is what happens
to all of the other cpus that were running in the crashed kernel. In an
attempt to avoid that problem this patch adds a nmi handler and attempts to
shoot down the other cpus by sending them non maskable interrupts.
The code then waits for 1 second or until all known cpus have stopped running
and then jumps from the running kernel that has crashed to the kernel in
reserved memory.
The kernel spin loop is used for the delay as that should behave continue to
be safe even in after a crash.
Signed-off-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is the i386 implementation of kexec.
Signed-off-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Vivek Goyal