x86/mce: Make timer handling more robust

Erik reported that on a preproduction hardware a CMCI storm triggers the
BUG_ON in add_timer_on(). The reason is that the per CPU MCE timer is
started by the CMCI logic before the MCE CPU hotplug callback starts the
timer with add_timer_on(). So the timer is already queued which triggers
the BUG.

Using add_timer_on() is pretty pointless in this code because the timer is
strictlty per CPU, initialized as pinned and all operations which arm the
timer happen on the CPU to which the timer belongs.

Simplify the whole machinery by using mod_timer() instead of add_timer_on()
which avoids the problem because mod_timer() can handle already queued
timers. Use __start_timer() everywhere so the earliest armed expiry time is
preserved.

Reported-by: Erik Veijola <erik.veijola@intel.com>
Tested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1701310936080.3457@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

path: root/include/crypto/ablk_helper.h

/*
 * Shared async block cipher helpers
 */

#ifndef _CRYPTO_ABLK_HELPER_H
#define _CRYPTO_ABLK_HELPER_H

#include <linux/crypto.h>
#include <linux/kernel.h>
#include <crypto/cryptd.h>

struct async_helper_ctx {
	struct cryptd_ablkcipher *cryptd_tfm;
};

extern int ablk_set_key(struct crypto_ablkcipher *tfm, const u8 *key,
			unsigned int key_len);

extern int __ablk_encrypt(struct ablkcipher_request *req);

extern int ablk_encrypt(struct ablkcipher_request *req);

extern int ablk_decrypt(struct ablkcipher_request *req);

extern void ablk_exit(struct crypto_tfm *tfm);

extern int ablk_init_common(struct crypto_tfm *tfm, const char *drv_name);

extern int ablk_init(struct crypto_tfm *tfm);

#endif /* _CRYPTO_ABLK_HELPER_H */