Replace call_smp_function with stop_machine_run in the Intel RNG driver.
CPU A has done read_lock(&lock)
CPU B has done write_lock_irq(&lock) and is waiting for A to release the lock.
A third CPU calls call_smp_function and issues the IPI. CPU A takes CPU
C's IPI. CPU B is waiting with interrupts disabled and does not see the
IPI. CPU C is stuck waiting for CPU B to respond to the IPI.
Deadlock.
The solution is to use stop_machine_run instead of call_smp_function
(call_smp_function should not be called in situations where the CPUs may be
suspended).
[haruo.tomita@toshiba.co.jp: fix a typo in mod_init()]
[haruo.tomita@toshiba.co.jp: fix memory leak]
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: "Tomita, Haruo" <haruo.tomita@toshiba.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This changes all HWRNG driver initcalls to module_init(). We must probe
the RNGs after the major kernel subsystems are already up and running (like
PCI).
This fixes Bug 7730.
http://bugzilla.kernel.org/show_bug.cgi?id=7730
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add a load option to intel-rng to allow skipping the FWH detection,
necessary in case the BIOS has locked read-only the firmware hub space.
Also prevent any attempt to write to firmware space if it cannot be write
enabled (apparently caused hangs on some systems not having an FWH and thus
also not having a respective RNG).
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Previously, since determination whether there was an Intel random number
generator was based on a single bit, on systems with a matching bridge
device but without a firmware hub, there was a 50% chance that the code
would incorrectly decide that the system had an RNG. This patch adds
detection of the firmware hub to better qualify the existence of an RNG.
There is one issue with the patch: I was unable to determine the LPC
equivalent for the PCI bridge 8086:2430 (since the old code didn't care
about which of the many devices provided by the ICH/ESB it was chose to use
the PCI bridge device, but the FWH settings live in the LPC device, so the
device list needed to be changed).
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The intel hwrng leaks an iomapped resource, if hwrng_register() failes.
This fixes it.
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
