From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752657AbaE0OLv (ORCPT ); Tue, 27 May 2014 10:11:51 -0400 Received: from verein.lst.de ([213.95.11.211]:60030 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751869AbaE0OLu (ORCPT ); Tue, 27 May 2014 10:11:50 -0400 Date: Tue, 27 May 2014 16:11:44 +0200 From: Torsten Duwe To: Andy Lutomirski Cc: "H. Peter Anvin" , "Theodore Ts'o" , Greg Kroah-Hartman , Andrew Morton , Matt Mackall , Herbert Xu , Arnd Bergmann , Rusty Russell , Satoru Takeuchi , ingo.tuchscherer@de.ibm.com, "linux-kernel@vger.kernel.org" , Hans-Georg Markgraf , Gerald Schaefer , Martin Schwidefsky , Heiko Carstens , Joe Perches Subject: [Patch v5.1 03/03]: hwrng: khwrngd derating per device Message-ID: <20140527141144.GE14099@lst.de> References: <20140321143342.GK1763@lst.de> <533375C1.5060904@mit.edu> <158d2776-1ea4-4f32-a9e9-0488047e6b70@email.android.com> <20140414160211.GE711@lst.de> <20140414160653.GC29351@lst.de> <20140415085126.GA17327@lst.de> <20140527134156.GA14099@lst.de> <20140527134645.GD14099@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140527134645.GD14099@lst.de> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [checkpatch tells me not to 0-init...] This patch introduces a derating factor to struct hwrng for the random bits going into the kernel input pool, and a common default derating for drivers which do not specify one. Signed-off-by: Torsten Duwe --- drivers/char/hw_random/core.c | 11 ++++++++++- include/linux/hw_random.h | 3 +++ 2 files changed, 13 insertions(+), 1 deletion(-) --- linux/include/linux/hw_random.h.orig +++ linux/include/linux/hw_random.h @@ -29,6 +29,8 @@ * @read: New API. drivers can fill up to max bytes of data * into the buffer. The buffer is aligned for any type. * @priv: Private data, for use by the RNG driver. + * @quality: Estimation of true entropy in RNG's bitstream + * (per mill). */ struct hwrng { const char *name; @@ -38,6 +39,7 @@ struct hwrng { int (*data_read)(struct hwrng *rng, u32 *data); int (*read)(struct hwrng *rng, void *data, size_t max, bool wait); unsigned long priv; + unsigned short quality; /* internal. */ struct list_head list; --- linux/drivers/char/hw_random/core.c.orig +++ linux/drivers/char/hw_random/core.c @@ -56,11 +56,15 @@ static LIST_HEAD(rng_list); static DEFINE_MUTEX(rng_mutex); static int data_avail; static u8 *rng_buffer, *rng_fillbuf; -static unsigned short current_quality = 700; /* an arbitrary 70% */ +static unsigned short current_quality; +static unsigned short default_quality; /* = 0; default to "off" */ module_param(current_quality, ushort, 0644); MODULE_PARM_DESC(current_quality, "current hwrng entropy estimation per mill"); +module_param(default_quality, ushort, 0644); +MODULE_PARM_DESC(default_quality, + "default entropy content of hwrng per mill"); static void start_khwrngd(void); @@ -79,6 +83,11 @@ static inline int hwrng_init(struct hwrn if (err) return err; + current_quality = rng->quality ? : default_quality; + current_quality &= 1023; + + if (current_quality == 0 && hwrng_fill) + kthread_stop(hwrng_fill); if (current_quality > 0 && !hwrng_fill) start_khwrngd();