17 files changed, 287 insertions, 159 deletions

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index e4fb3374dcd2..2c2d2e5c1597 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -888,9 +888,8 @@ static int setup_blkring(struct xenbus_device *dev,
         if (err)
                 goto fail;
 
-        err = bind_evtchn_to_irqhandler(info->evtchn,
-                                        blkif_interrupt,
-                                        IRQF_SAMPLE_RANDOM, "blkif", info);
+        err = bind_evtchn_to_irqhandler(info->evtchn, blkif_interrupt, 0,
+                                        "blkif", info);
         if (err <= 0) {
                 xenbus_dev_fatal(dev, err,
                                  "bind_evtchn_to_irqhandler failed");
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 4ec04a754733..b86eae9b77df 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -125,21 +125,26 @@
  * The current exported interfaces for gathering environmental noise
  * from the devices are:
  *
+ *      void add_device_randomness(const void *buf, unsigned int size);
  *      void add_input_randomness(unsigned int type, unsigned int code,
  *                                unsigned int value);
- *      void add_interrupt_randomness(int irq);
+ *      void add_interrupt_randomness(int irq, int irq_flags);
  *      void add_disk_randomness(struct gendisk *disk);
  *
+ * add_device_randomness() is for adding data to the random pool that
+ * is likely to differ between two devices (or possibly even per boot).
+ * This would be things like MAC addresses or serial numbers, or the
+ * read-out of the RTC. This does *not* add any actual entropy to the
+ * pool, but it initializes the pool to different values for devices
+ * that might otherwise be identical and have very little entropy
+ * available to them (particularly common in the embedded world).
+ *
  * add_input_randomness() uses the input layer interrupt timing, as well as
  * the event type information from the hardware.
  *
- * add_interrupt_randomness() uses the inter-interrupt timing as random
- * inputs to the entropy pool.  Note that not all interrupts are good
- * sources of randomness!  For example, the timer interrupts is not a
- * good choice, because the periodicity of the interrupts is too
- * regular, and hence predictable to an attacker.  Network Interface
- * Controller interrupts are a better measure, since the timing of the
- * NIC interrupts are more unpredictable.
+ * add_interrupt_randomness() uses the interrupt timing as random
+ * inputs to the entropy pool. Using the cycle counters and the irq source
+ * as inputs, it feeds the randomness roughly once a second.
  *
  * add_disk_randomness() uses what amounts to the seek time of block
  * layer request events, on a per-disk_devt basis, as input to the
@@ -248,6 +253,8 @@
 #include <linux/percpu.h>
 #include <linux/cryptohash.h>
 #include <linux/fips.h>
+#include <linux/ptrace.h>
+#include <linux/kmemcheck.h>
 
 #ifdef CONFIG_GENERIC_HARDIRQS
 # include <linux/irq.h>
@@ -256,8 +263,12 @@
 #include <asm/processor.h>
 #include <asm/uaccess.h>
 #include <asm/irq.h>
+#include <asm/irq_regs.h>
 #include <asm/io.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/random.h>
+
 /*
  * Configuration information
  */
@@ -266,6 +277,8 @@
 #define SEC_XFER_SIZE 512
 #define EXTRACT_SIZE 10
 
+#define LONGS(x) (((x) + sizeof(unsigned long) - 1)/sizeof(unsigned long))
+
 /*
  * The minimum number of bits of entropy before we wake up a read on
  * /dev/random.  Should be enough to do a significant reseed.
@@ -420,8 +433,10 @@ struct entropy_store {
         /* read-write data: */
         spinlock_t lock;
         unsigned add_ptr;
+        unsigned input_rotate;
         int entropy_count;
-        int input_rotate;
+        int entropy_total;
+        unsigned int initialized:1;
         __u8 last_data[EXTRACT_SIZE];
 };
 
@@ -454,6 +469,10 @@ static struct entropy_store nonblocking_pool = {
         .pool = nonblocking_pool_data
 };
 
+static __u32 const twist_table[8] = {
+        0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158,
+        0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 };
+
 /*
  * This function adds bytes into the entropy "pool".  It does not
  * update the entropy estimate.  The caller should call
@@ -464,29 +483,24 @@ static struct entropy_store nonblocking_pool = {
  * it's cheap to do so and helps slightly in the expected case where
  * the entropy is concentrated in the low-order bits.
  */
-static void mix_pool_bytes_extract(struct entropy_store *r, const void *in,
-                                   int nbytes, __u8 out[64])
+static void _mix_pool_bytes(struct entropy_store *r, const void *in,
+                            int nbytes, __u8 out[64])
 {
-        static __u32 const twist_table[8] = {
-                0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158,
-                0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 };
         unsigned long i, j, tap1, tap2, tap3, tap4, tap5;
         int input_rotate;
         int wordmask = r->poolinfo->poolwords - 1;
         const char *bytes = in;
         __u32 w;
-        unsigned long flags;
 
-        /* Taps are constant, so we can load them without holding r->lock.  */
         tap1 = r->poolinfo->tap1;
         tap2 = r->poolinfo->tap2;
         tap3 = r->poolinfo->tap3;
         tap4 = r->poolinfo->tap4;
         tap5 = r->poolinfo->tap5;
 
-        spin_lock_irqsave(&r->lock, flags);
-        input_rotate = r->input_rotate;
-        i = r->add_ptr;
+        smp_rmb();
+        input_rotate = ACCESS_ONCE(r->input_rotate);
+        i = ACCESS_ONCE(r->add_ptr);
 
         /* mix one byte at a time to simplify size handling and churn faster */
         while (nbytes--) {
@@ -513,19 +527,61 @@ static void mix_pool_bytes_extract(struct entropy_store *r, const void *in,
                 input_rotate += i ? 7 : 14;
         }
 
-        r->input_rotate = input_rotate;
-        r->add_ptr = i;
+        ACCESS_ONCE(r->input_rotate) = input_rotate;
+        ACCESS_ONCE(r->add_ptr) = i;
+        smp_wmb();
 
         if (out)
                 for (j = 0; j < 16; j++)
                         ((__u32 *)out)[j] = r->pool[(i - j) & wordmask];
+}
+
+static void __mix_pool_bytes(struct entropy_store *r, const void *in,
+                             int nbytes, __u8 out[64])
+{
+        trace_mix_pool_bytes_nolock(r->name, nbytes, _RET_IP_);
+        _mix_pool_bytes(r, in, nbytes, out);
+}
+
+static void mix_pool_bytes(struct entropy_store *r, const void *in,
+                           int nbytes, __u8 out[64])
+{
+        unsigned long flags;
 
+        trace_mix_pool_bytes(r->name, nbytes, _RET_IP_);
+        spin_lock_irqsave(&r->lock, flags);
+        _mix_pool_bytes(r, in, nbytes, out);
         spin_unlock_irqrestore(&r->lock, flags);
 }
 
-static void mix_pool_bytes(struct entropy_store *r, const void *in, int bytes)
+struct fast_pool {
+        __u32           pool[4];
+        unsigned long   last;
+        unsigned short  count;
+        unsigned char   rotate;
+        unsigned char   last_timer_intr;
+};
+
+/*
+ * This is a fast mixing routine used by the interrupt randomness
+ * collector.  It's hardcoded for an 128 bit pool and assumes that any
+ * locks that might be needed are taken by the caller.
+ */
+static void fast_mix(struct fast_pool *f, const void *in, int nbytes)
 {
-       mix_pool_bytes_extract(r, in, bytes, NULL);
+        const char      *bytes = in;
+        __u32           w;
+        unsigned        i = f->count;
+        unsigned        input_rotate = f->rotate;
+
+        while (nbytes--) {
+                w = rol32(*bytes++, input_rotate & 31) ^ f->pool[i & 3] ^
+                        f->pool[(i + 1) & 3];
+                f->pool[i & 3] = (w >> 3) ^ twist_table[w & 7];
+                input_rotate += (i++ & 3) ? 7 : 14;
+        }
+        f->count = i;
+        f->rotate = input_rotate;
 }
 
 /*
@@ -533,30 +589,38 @@ static void mix_pool_bytes(struct entropy_store *r, const void *in, int bytes)
  */
 static void credit_entropy_bits(struct entropy_store *r, int nbits)
 {
-        unsigned long flags;
-        int entropy_count;
+        int entropy_count, orig;
 
         if (!nbits)
                 return;
 
-        spin_lock_irqsave(&r->lock, flags);
-
         DEBUG_ENT("added %d entropy credits to %s\n", nbits, r->name);
-        entropy_count = r->entropy_count;
+retry:
+        entropy_count = orig = ACCESS_ONCE(r->entropy_count);
         entropy_count += nbits;
+
         if (entropy_count < 0) {
                 DEBUG_ENT("negative entropy/overflow\n");
                 entropy_count = 0;
         } else if (entropy_count > r->poolinfo->POOLBITS)
                 entropy_count = r->poolinfo->POOLBITS;
-        r->entropy_count = entropy_count;
+        if (cmpxchg(&r->entropy_count, orig, entropy_count) != orig)
+                goto retry;
+
+        if (!r->initialized && nbits > 0) {
+                r->entropy_total += nbits;
+                if (r->entropy_total > 128)
+                        r->initialized = 1;
+        }
+
+        trace_credit_entropy_bits(r->name, nbits, entropy_count,
+                                  r->entropy_total, _RET_IP_);
 
         /* should we wake readers? */
         if (r == &input_pool && entropy_count >= random_read_wakeup_thresh) {
                 wake_up_interruptible(&random_read_wait);
                 kill_fasync(&fasync, SIGIO, POLL_IN);
         }
-        spin_unlock_irqrestore(&r->lock, flags);
 }
 
 /*********************************************************************
@@ -572,42 +636,24 @@ struct timer_rand_state {
         unsigned dont_count_entropy:1;
 };
 
-#ifndef CONFIG_GENERIC_HARDIRQS
-
-static struct timer_rand_state *irq_timer_state[NR_IRQS];
-
-static struct timer_rand_state *get_timer_rand_state(unsigned int irq)
-{
-        return irq_timer_state[irq];
-}
-
-static void set_timer_rand_state(unsigned int irq,
-                                 struct timer_rand_state *state)
-{
-        irq_timer_state[irq] = state;
-}
-
-#else
-
-static struct timer_rand_state *get_timer_rand_state(unsigned int irq)
-{
-        struct irq_desc *desc;
-
-        desc = irq_to_desc(irq);
-
-        return desc->timer_rand_state;
-}
-
-static void set_timer_rand_state(unsigned int irq,
-                                 struct timer_rand_state *state)
+/*
+ * Add device- or boot-specific data to the input and nonblocking
+ * pools to help initialize them to unique values.
+ *
+ * None of this adds any entropy, it is meant to avoid the
+ * problem of the nonblocking pool having similar initial state
+ * across largely identical devices.
+ */
+void add_device_randomness(const void *buf, unsigned int size)
 {
-        struct irq_desc *desc;
+        unsigned long time = get_cycles() ^ jiffies;
 
-        desc = irq_to_desc(irq);
-
-        desc->timer_rand_state = state;
+        mix_pool_bytes(&input_pool, buf, size, NULL);
+        mix_pool_bytes(&input_pool, &time, sizeof(time), NULL);
+        mix_pool_bytes(&nonblocking_pool, buf, size, NULL);
+        mix_pool_bytes(&nonblocking_pool, &time, sizeof(time), NULL);
 }
-#endif
+EXPORT_SYMBOL(add_device_randomness);
 
 static struct timer_rand_state input_timer_state;
 
@@ -637,13 +683,9 @@ static void add_timer_randomness(struct timer_rand_state *state, unsigned num)
                 goto out;
 
         sample.jiffies = jiffies;
-
-        /* Use arch random value, fall back to cycles */
-        if (!arch_get_random_int(&sample.cycles))
-                sample.cycles = get_cycles();
-
+        sample.cycles = get_cycles();
         sample.num = num;
-        mix_pool_bytes(&input_pool, &sample, sizeof(sample));
+        mix_pool_bytes(&input_pool, &sample, sizeof(sample), NULL);
 
         /*
          * Calculate number of bits of randomness we probably added.
@@ -700,17 +742,48 @@ void add_input_randomness(unsigned int type, unsigned int code,
 }
 EXPORT_SYMBOL_GPL(add_input_randomness);
 
-void add_interrupt_randomness(int irq)
+static DEFINE_PER_CPU(struct fast_pool, irq_randomness);
+
+void add_interrupt_randomness(int irq, int irq_flags)
 {
-        struct timer_rand_state *state;
+        struct entropy_store    *r;
+        struct fast_pool        *fast_pool = &__get_cpu_var(irq_randomness);
+        struct pt_regs          *regs = get_irq_regs();
+        unsigned long           now = jiffies;
+        __u32                   input[4], cycles = get_cycles();
+
+        input[0] = cycles ^ jiffies;
+        input[1] = irq;
+        if (regs) {
+                __u64 ip = instruction_pointer(regs);
+                input[2] = ip;
+                input[3] = ip >> 32;
+        }
 
-        state = get_timer_rand_state(irq);
+        fast_mix(fast_pool, input, sizeof(input));
 
-        if (state == NULL)
+        if ((fast_pool->count & 1023) &&
+            !time_after(now, fast_pool->last + HZ))
                 return;
 
-        DEBUG_ENT("irq event %d\n", irq);
-        add_timer_randomness(state, 0x100 + irq);
+        fast_pool->last = now;
+
+        r = nonblocking_pool.initialized ? &input_pool : &nonblocking_pool;
+        __mix_pool_bytes(r, &fast_pool->pool, sizeof(fast_pool->pool), NULL);
+        /*
+         * If we don't have a valid cycle counter, and we see
+         * back-to-back timer interrupts, then skip giving credit for
+         * any entropy.
+         */
+        if (cycles == 0) {
+                if (irq_flags & __IRQF_TIMER) {
+                        if (fast_pool->last_timer_intr)
+                                return;
+                        fast_pool->last_timer_intr = 1;
+                } else
+                        fast_pool->last_timer_intr = 0;
+        }
+        credit_entropy_bits(r, 1);
 }
 
 #ifdef CONFIG_BLOCK
@@ -742,7 +815,7 @@ static ssize_t extract_entropy(struct entropy_store *r, void *buf,
  */
 static void xfer_secondary_pool(struct entropy_store *r, size_t nbytes)
 {
-        __u32 tmp[OUTPUT_POOL_WORDS];
+        __u32   tmp[OUTPUT_POOL_WORDS];
 
         if (r->pull && r->entropy_count < nbytes * 8 &&
             r->entropy_count < r->poolinfo->POOLBITS) {
@@ -761,7 +834,7 @@ static void xfer_secondary_pool(struct entropy_store *r, size_t nbytes)
 
                 bytes = extract_entropy(r->pull, tmp, bytes,
                                         random_read_wakeup_thresh / 8, rsvd);
-                mix_pool_bytes(r, tmp, bytes);
+                mix_pool_bytes(r, tmp, bytes, NULL);
                 credit_entropy_bits(r, bytes*8);
         }
 }
@@ -820,13 +893,19 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min,
 static void extract_buf(struct entropy_store *r, __u8 *out)
 {
         int i;
-        __u32 hash[5], workspace[SHA_WORKSPACE_WORDS];
+        union {
+                __u32 w[5];
+                unsigned long l[LONGS(EXTRACT_SIZE)];
+        } hash;
+        __u32 workspace[SHA_WORKSPACE_WORDS];
         __u8 extract[64];
+        unsigned long flags;
 
         /* Generate a hash across the pool, 16 words (512 bits) at a time */
-        sha_init(hash);
+        sha_init(hash.w);
+        spin_lock_irqsave(&r->lock, flags);
         for (i = 0; i < r->poolinfo->poolwords; i += 16)
-                sha_transform(hash, (__u8 *)(r->pool + i), workspace);
+                sha_transform(hash.w, (__u8 *)(r->pool + i), workspace);
 
         /*
          * We mix the hash back into the pool to prevent backtracking
@@ -837,13 +916,14 @@ static void extract_buf(struct entropy_store *r, __u8 *out)
          * brute-forcing the feedback as hard as brute-forcing the
          * hash.
          */
-        mix_pool_bytes_extract(r, hash, sizeof(hash), extract);
+        __mix_pool_bytes(r, hash.w, sizeof(hash.w), extract);
+        spin_unlock_irqrestore(&r->lock, flags);
 
         /*
          * To avoid duplicates, we atomically extract a portion of the
          * pool while mixing, and hash one final time.
          */
-        sha_transform(hash, extract, workspace);
+        sha_transform(hash.w, extract, workspace);
         memset(extract, 0, sizeof(extract));
         memset(workspace, 0, sizeof(workspace));
 
@@ -852,20 +932,32 @@ static void extract_buf(struct entropy_store *r, __u8 *out)
          * pattern, we fold it in half. Thus, we always feed back
          * twice as much data as we output.
          */
-        hash[0] ^= hash[3];
-        hash[1] ^= hash[4];
-        hash[2] ^= rol32(hash[2], 16);
-        memcpy(out, hash, EXTRACT_SIZE);
-        memset(hash, 0, sizeof(hash));
+        hash.w[0] ^= hash.w[3];
+        hash.w[1] ^= hash.w[4];
+        hash.w[2] ^= rol32(hash.w[2], 16);
+
+        /*
+         * If we have a architectural hardware random number
+         * generator, mix that in, too.
+         */
+        for (i = 0; i < LONGS(EXTRACT_SIZE); i++) {
+                unsigned long v;
+                if (!arch_get_random_long(&v))
+                        break;
+                hash.l[i] ^= v;
+        }
+
+        memcpy(out, &hash, EXTRACT_SIZE);
+        memset(&hash, 0, sizeof(hash));
 }
 
 static ssize_t extract_entropy(struct entropy_store *r, void *buf,
-                               size_t nbytes, int min, int reserved)
+                                 size_t nbytes, int min, int reserved)
 {
         ssize_t ret = 0, i;
         __u8 tmp[EXTRACT_SIZE];
-        unsigned long flags;
 
+        trace_extract_entropy(r->name, nbytes, r->entropy_count, _RET_IP_);
         xfer_secondary_pool(r, nbytes);
         nbytes = account(r, nbytes, min, reserved);
 
@@ -873,6 +965,8 @@ static ssize_t extract_entropy(struct entropy_store *r, void *buf,
                 extract_buf(r, tmp);
 
                 if (fips_enabled) {
+                        unsigned long flags;
+
                         spin_lock_irqsave(&r->lock, flags);
                         if (!memcmp(tmp, r->last_data, EXTRACT_SIZE))
                                 panic("Hardware RNG duplicated output!\n");
@@ -898,6 +992,7 @@ static ssize_t extract_entropy_user(struct entropy_store *r, void __user *buf,
         ssize_t ret = 0, i;
         __u8 tmp[EXTRACT_SIZE];
 
+        trace_extract_entropy_user(r->name, nbytes, r->entropy_count, _RET_IP_);
         xfer_secondary_pool(r, nbytes);
         nbytes = account(r, nbytes, 0, 0);
 
@@ -931,17 +1026,35 @@ static ssize_t extract_entropy_user(struct entropy_store *r, void __user *buf,
 
 /*
  * This function is the exported kernel interface.  It returns some
- * number of good random numbers, suitable for seeding TCP sequence
- * numbers, etc.
+ * number of good random numbers, suitable for key generation, seeding
+ * TCP sequence numbers, etc.  It does not use the hw random number
+ * generator, if available; use get_random_bytes_arch() for that.
  */
 void get_random_bytes(void *buf, int nbytes)
 {
+        extract_entropy(&nonblocking_pool, buf, nbytes, 0, 0);
+}
+EXPORT_SYMBOL(get_random_bytes);
+
+/*
+ * This function will use the architecture-specific hardware random
+ * number generator if it is available.  The arch-specific hw RNG will
+ * almost certainly be faster than what we can do in software, but it
+ * is impossible to verify that it is implemented securely (as
+ * opposed, to, say, the AES encryption of a sequence number using a
+ * key known by the NSA).  So it's useful if we need the speed, but
+ * only if we're willing to trust the hardware manufacturer not to
+ * have put in a back door.
+ */
+void get_random_bytes_arch(void *buf, int nbytes)
+{
         char *p = buf;
 
+        trace_get_random_bytes(nbytes, _RET_IP_);
         while (nbytes) {
                 unsigned long v;
                 int chunk = min(nbytes, (int)sizeof(unsigned long));
-                
+
                 if (!arch_get_random_long(&v))
                         break;
                 
@@ -950,9 +1063,11 @@ void get_random_bytes(void *buf, int nbytes)
                 nbytes -= chunk;
         }
 
-        extract_entropy(&nonblocking_pool, p, nbytes, 0, 0);
+        if (nbytes)
+                extract_entropy(&nonblocking_pool, p, nbytes, 0, 0);
 }
-EXPORT_SYMBOL(get_random_bytes);
+EXPORT_SYMBOL(get_random_bytes_arch);
+
 
 /*
  * init_std_data - initialize pool with system data
@@ -966,23 +1081,30 @@ EXPORT_SYMBOL(get_random_bytes);
 static void init_std_data(struct entropy_store *r)
 {
         int i;
-        ktime_t now;
-        unsigned long flags;
+        ktime_t now = ktime_get_real();
+        unsigned long rv;
 
-        spin_lock_irqsave(&r->lock, flags);
         r->entropy_count = 0;
-        spin_unlock_irqrestore(&r->lock, flags);
-
-        now = ktime_get_real();
-        mix_pool_bytes(r, &now, sizeof(now));
-        for (i = r->poolinfo->POOLBYTES; i > 0; i -= sizeof flags) {
-                if (!arch_get_random_long(&flags))
+        r->entropy_total = 0;
+        mix_pool_bytes(r, &now, sizeof(now), NULL);
+        for (i = r->poolinfo->POOLBYTES; i > 0; i -= sizeof(rv)) {
+                if (!arch_get_random_long(&rv))
                         break;
-                mix_pool_bytes(r, &flags, sizeof(flags));
+                mix_pool_bytes(r, &rv, sizeof(rv), NULL);
         }
-        mix_pool_bytes(r, utsname(), sizeof(*(utsname())));
+        mix_pool_bytes(r, utsname(), sizeof(*(utsname())), NULL);
 }
 
+/*
+ * Note that setup_arch() may call add_device_randomness()
+ * long before we get here. This allows seeding of the pools
+ * with some platform dependent data very early in the boot
+ * process. But it limits our options here. We must use
+ * statically allocated structures that already have all
+ * initializations complete at compile time. We should also
+ * take care not to overwrite the precious per platform data
+ * we were given.
+ */
 static int rand_initialize(void)
 {
         init_std_data(&input_pool);
@@ -992,24 +1114,6 @@ static int rand_initialize(void)
 }
 module_init(rand_initialize);
 
-void rand_initialize_irq(int irq)
-{
-        struct timer_rand_state *state;
-
-        state = get_timer_rand_state(irq);
-
-        if (state)
-                return;
-
-        /*
-         * If kzalloc returns null, we just won't use that entropy
-         * source.
-         */
-        state = kzalloc(sizeof(struct timer_rand_state), GFP_KERNEL);
-        if (state)
-                set_timer_rand_state(irq, state);
-}
-
 #ifdef CONFIG_BLOCK
 void rand_initialize_disk(struct gendisk *disk)
 {
@@ -1117,7 +1221,7 @@ write_pool(struct entropy_store *r, const char __user *buffer, size_t count)
                 count -= bytes;
                 p += bytes;
 
-                mix_pool_bytes(r, buf, bytes);
+                mix_pool_bytes(r, buf, bytes, NULL);
                 cond_resched();
         }
 
@@ -1279,6 +1383,7 @@ static int proc_do_uuid(ctl_table *table, int write,
 }
 
 static int sysctl_poolsize = INPUT_POOL_WORDS * 32;
+extern ctl_table random_table[];
 ctl_table random_table[] = {
         {
                 .procname       = "poolsize",
@@ -1344,7 +1449,7 @@ late_initcall(random_int_secret_init);
  * value is not cryptographically secure but for several uses the cost of
  * depleting entropy is too high
  */
-DEFINE_PER_CPU(__u32 [MD5_DIGEST_WORDS], get_random_int_hash);
+static DEFINE_PER_CPU(__u32 [MD5_DIGEST_WORDS], get_random_int_hash);
 unsigned int get_random_int(void)
 {
         __u32 *hash;
diff --git a/drivers/crypto/n2_core.c b/drivers/crypto/n2_core.c
index 67b97c5fd859..a8bd0310f8fe 100644
--- a/drivers/crypto/n2_core.c
+++ b/drivers/crypto/n2_core.c
@@ -1610,8 +1610,7 @@ static int spu_map_ino(struct platform_device *dev, struct spu_mdesc_info *ip,
 
         sprintf(p->irq_name, "%s-%d", irq_name, index);
 
-        return request_irq(p->irq, handler, IRQF_SAMPLE_RANDOM,
-                           p->irq_name, p);
+        return request_irq(p->irq, handler, 0, p->irq_name, p);
 }
 
 static struct kmem_cache *queue_cache[2];
diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 153980be4ee6..b298158cb922 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -6,6 +6,7 @@
 #include <linux/dmi.h>
 #include <linux/efi.h>
 #include <linux/bootmem.h>
+#include <linux/random.h>
 #include <asm/dmi.h>
 
 /*
@@ -111,6 +112,8 @@ static int __init dmi_walk_early(void (*decode)(const struct dmi_header *,
 
         dmi_table(buf, dmi_len, dmi_num, decode, NULL);
 
+        add_device_randomness(buf, dmi_len);
+
         dmi_iounmap(buf, dmi_len);
         return 0;
 }
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index a220e5746d67..4748086eaaf2 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -545,8 +545,7 @@ static int vmbus_bus_init(int irq)
         if (ret)
                 goto err_cleanup;
 
-        ret = request_irq(irq, vmbus_isr, IRQF_SAMPLE_RANDOM,
-                        driver_name, hv_acpi_dev);
+        ret = request_irq(irq, vmbus_isr, 0, driver_name, hv_acpi_dev);
 
         if (ret != 0) {
                 pr_err("Unable to request IRQ %d\n",
diff --git a/drivers/i2c/busses/i2c-pmcmsp.c b/drivers/i2c/busses/i2c-pmcmsp.c
index 07b7447ecbc9..3d71395ae1f7 100644
--- a/drivers/i2c/busses/i2c-pmcmsp.c
+++ b/drivers/i2c/busses/i2c-pmcmsp.c
@@ -306,8 +306,7 @@ static int __devinit pmcmsptwi_probe(struct platform_device *pldev)
         pmcmsptwi_data.irq = platform_get_irq(pldev, 0);
         if (pmcmsptwi_data.irq) {
                 rc = request_irq(pmcmsptwi_data.irq, &pmcmsptwi_interrupt,
-                        IRQF_SHARED | IRQF_SAMPLE_RANDOM,
-                        pldev->name, &pmcmsptwi_data);
+                                 IRQF_SHARED, pldev->name, &pmcmsptwi_data);
                 if (rc == 0) {
                         /*
                          * Enable 'DONE' interrupt only.
diff --git a/drivers/input/serio/hp_sdc.c b/drivers/input/serio/hp_sdc.c
index 09a089996ded..d7a7e54f6465 100644
--- a/drivers/input/serio/hp_sdc.c
+++ b/drivers/input/serio/hp_sdc.c
@@ -878,7 +878,7 @@ static int __init hp_sdc_init(void)
 #endif
 
         errstr = "IRQ not available for";
-        if (request_irq(hp_sdc.irq, &hp_sdc_isr, IRQF_SHARED|IRQF_SAMPLE_RANDOM,
+        if (request_irq(hp_sdc.irq, &hp_sdc_isr, IRQF_SHARED,
                         "HP SDC", &hp_sdc))
                 goto err1;
 
diff --git a/drivers/mfd/ab3100-core.c b/drivers/mfd/ab3100-core.c
index 4276aab4f196..78fca2902c8d 100644
--- a/drivers/mfd/ab3100-core.c
+++ b/drivers/mfd/ab3100-core.c
@@ -409,8 +409,6 @@ static irqreturn_t ab3100_irq_handler(int irq, void *data)
         u32 fatevent;
         int err;
 
-        add_interrupt_randomness(irq);
-
         err = ab3100_get_register_page_interruptible(ab3100, AB3100_EVENTA1,
                                        event_regs, 3);
         if (err)
@@ -936,8 +934,6 @@ static int __devinit ab3100_probe(struct i2c_client *client,
                                         IRQF_ONESHOT, "ab3100-core", ab3100);
         if (err)
                 goto exit_no_irq;
-        /* This real unpredictable IRQ is of course sampled for entropy */
-        rand_initialize_irq(client->irq);
 
         err = abx500_register_ops(&client->dev, &ab3100_ops);
         if (err)
diff --git a/drivers/mfd/tps65010.c b/drivers/mfd/tps65010.c
index 93d5fdf020c7..da2691f22e11 100644
--- a/drivers/mfd/tps65010.c
+++ b/drivers/mfd/tps65010.c
@@ -563,8 +563,7 @@ static int tps65010_probe(struct i2c_client *client,
          */
         if (client->irq > 0) {
                 status = request_irq(client->irq, tps65010_irq,
-                        IRQF_SAMPLE_RANDOM | IRQF_TRIGGER_FALLING,
-                        DRIVER_NAME, tps);
+                                     IRQF_TRIGGER_FALLING, DRIVER_NAME, tps);
                 if (status < 0) {
                         dev_dbg(&client->dev, "can't get IRQ %d, err %d\n",
                                         client->irq, status);
diff --git a/drivers/mfd/wm831x-otp.c b/drivers/mfd/wm831x-otp.c
index f742745ff354..b90f3e06b6c9 100644
--- a/drivers/mfd/wm831x-otp.c
+++ b/drivers/mfd/wm831x-otp.c
@@ -18,6 +18,7 @@
 #include <linux/bcd.h>
 #include <linux/delay.h>
 #include <linux/mfd/core.h>
+#include <linux/random.h>
 
 #include <linux/mfd/wm831x/core.h>
 #include <linux/mfd/wm831x/otp.h>
@@ -66,6 +67,7 @@ static DEVICE_ATTR(unique_id, 0444, wm831x_unique_id_show, NULL);
 
 int wm831x_otp_init(struct wm831x *wm831x)
 {
+        char uuid[WM831X_UNIQUE_ID_LEN];
         int ret;
 
         ret = device_create_file(wm831x->dev, &dev_attr_unique_id);
@@ -73,6 +75,12 @@ int wm831x_otp_init(struct wm831x *wm831x)
                 dev_err(wm831x->dev, "Unique ID attribute not created: %d\n",
                         ret);
 
+        ret = wm831x_unique_id_read(wm831x, uuid);
+        if (ret == 0)
+                add_device_randomness(uuid, sizeof(uuid));
+        else
+                dev_err(wm831x->dev, "Failed to read UUID: %d\n", ret);
+
         return ret;
 }
 
diff --git a/drivers/power/pda_power.c b/drivers/power/pda_power.c
index 6a1ca735e935..7312f2651647 100644
--- a/drivers/power/pda_power.c
+++ b/drivers/power/pda_power.c
@@ -24,11 +24,7 @@
 
 static inline unsigned int get_irq_flags(struct resource *res)
 {
-        unsigned int flags = IRQF_SAMPLE_RANDOM | IRQF_SHARED;
-
-        flags |= res->flags & IRQF_TRIGGER_MASK;
-
-        return flags;
+        return IRQF_SHARED | (res->flags & IRQF_TRIGGER_MASK);
 }
 
 static struct device *dev;
diff --git a/drivers/rtc/rtc-wm831x.c b/drivers/rtc/rtc-wm831x.c
index 59c6245e0421..ea5c6f857ca5 100644
--- a/drivers/rtc/rtc-wm831x.c
+++ b/drivers/rtc/rtc-wm831x.c
@@ -24,7 +24,7 @@
 #include <linux/mfd/wm831x/core.h>
 #include <linux/delay.h>
 #include <linux/platform_device.h>
-
+#include <linux/random.h>
 
 /*
  * R16416 (0x4020) - RTC Write Counter
@@ -96,6 +96,26 @@ struct wm831x_rtc {
         unsigned int alarm_enabled:1;
 };
 
+static void wm831x_rtc_add_randomness(struct wm831x *wm831x)
+{
+        int ret;
+        u16 reg;
+
+        /*
+         * The write counter contains a pseudo-random number which is
+         * regenerated every time we set the RTC so it should be a
+         * useful per-system source of entropy.
+         */
+        ret = wm831x_reg_read(wm831x, WM831X_RTC_WRITE_COUNTER);
+        if (ret >= 0) {
+                reg = ret;
+                add_device_randomness(&reg, sizeof(reg));
+        } else {
+                dev_warn(wm831x->dev, "Failed to read RTC write counter: %d\n",
+                         ret);
+        }
+}
+
 /*
  * Read current time and date in RTC
  */
@@ -431,6 +451,8 @@ static int wm831x_rtc_probe(struct platform_device *pdev)
                         alm_irq, ret);
         }
 
+        wm831x_rtc_add_randomness(wm831x);
+
         return 0;
 
 err:
diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
index 6cd414341d5e..6579ffdd8e9b 100644
--- a/drivers/tty/serial/uartlite.c
+++ b/drivers/tty/serial/uartlite.c
@@ -216,8 +216,7 @@ static int ulite_startup(struct uart_port *port)
 {
         int ret;
 
-        ret = request_irq(port->irq, ulite_isr,
-                          IRQF_SHARED | IRQF_SAMPLE_RANDOM, "uartlite", port);
+        ret = request_irq(port->irq, ulite_isr, IRQF_SHARED, "uartlite", port);
         if (ret)
                 return ret;
 
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 821126eb8176..128a804c42f4 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -25,6 +25,7 @@
 #include <linux/kthread.h>
 #include <linux/mutex.h>
 #include <linux/freezer.h>
+#include <linux/random.h>
 
 #include <asm/uaccess.h>
 #include <asm/byteorder.h>
@@ -2181,6 +2182,14 @@ int usb_new_device(struct usb_device *udev)
         /* Tell the world! */
         announce_device(udev);
 
+        if (udev->serial)
+                add_device_randomness(udev->serial, strlen(udev->serial));
+        if (udev->product)
+                add_device_randomness(udev->product, strlen(udev->product));
+        if (udev->manufacturer)
+                add_device_randomness(udev->manufacturer,
+                                      strlen(udev->manufacturer));
+
         device_enable_async_suspend(&udev->dev);
 
         /*
diff --git a/drivers/usb/gadget/goku_udc.c b/drivers/usb/gadget/goku_udc.c
index 3d28fb976c78..9fd7886cfa9a 100644
--- a/drivers/usb/gadget/goku_udc.c
+++ b/drivers/usb/gadget/goku_udc.c
@@ -1836,7 +1836,7 @@ static int goku_probe(struct pci_dev *pdev, const struct pci_device_id *id)
         /* init to known state, then setup irqs */
         udc_reset(dev);
         udc_reinit (dev);
-        if (request_irq(pdev->irq, goku_irq, IRQF_SHARED/*|IRQF_SAMPLE_RANDOM*/,
+        if (request_irq(pdev->irq, goku_irq, IRQF_SHARED,
                         driver_name, dev) != 0) {
                 DBG(dev, "request interrupt %d failed\n", pdev->irq);
                 retval = -EBUSY;
diff --git a/drivers/usb/gadget/pxa25x_udc.c b/drivers/usb/gadget/pxa25x_udc.c
index 53c093b941e5..907ad3ecb341 100644
--- a/drivers/usb/gadget/pxa25x_udc.c
+++ b/drivers/usb/gadget/pxa25x_udc.c
@@ -2201,19 +2201,15 @@ static int __init pxa25x_udc_probe(struct platform_device *pdev)
 
 #ifdef CONFIG_ARCH_LUBBOCK
         if (machine_is_lubbock()) {
-                retval = request_irq(LUBBOCK_USB_DISC_IRQ,
-                                lubbock_vbus_irq,
-                                IRQF_SAMPLE_RANDOM,
-                                driver_name, dev);
+                retval = request_irq(LUBBOCK_USB_DISC_IRQ, lubbock_vbus_irq,
+                                     0, driver_name, dev);
                 if (retval != 0) {
                         pr_err("%s: can't get irq %i, err %d\n",
                                 driver_name, LUBBOCK_USB_DISC_IRQ, retval);
                         goto err_irq_lub;
                 }
-                retval = request_irq(LUBBOCK_USB_IRQ,
-                                lubbock_vbus_irq,
-                                IRQF_SAMPLE_RANDOM,
-                                driver_name, dev);
+                retval = request_irq(LUBBOCK_USB_IRQ, lubbock_vbus_irq,
+                                     0, driver_name, dev);
                 if (retval != 0) {
                         pr_err("%s: can't get irq %i, err %d\n",
                                 driver_name, LUBBOCK_USB_IRQ, retval);
diff --git a/drivers/usb/otg/isp1301_omap.c b/drivers/usb/otg/isp1301_omap.c
index 575fc815c932..7a88667742b6 100644
--- a/drivers/usb/otg/isp1301_omap.c
+++ b/drivers/usb/otg/isp1301_omap.c
@@ -1576,7 +1576,6 @@ isp1301_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
                 isp->irq_type = IRQF_TRIGGER_FALLING;
         }
 
-        isp->irq_type |= IRQF_SAMPLE_RANDOM;
         status = request_irq(i2c->irq, isp1301_irq,
                         isp->irq_type, DRIVER_NAME, isp);
         if (status < 0) {