From c7b375747cffb627d02543d946b28525455d7d46 Mon Sep 17 00:00:00 2001
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From: "Hongzhi.Song" <hongzhi.song@windriver.com>
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Date: Fri, 13 Jul 2018 06:06:19 -0700
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Subject: [PATCH] vm: add some funtions to support musl libc
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Signed-off-by: Hongzhi.Song <hongzhi.song@windriver.com>
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---
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tools/testing/selftests/vm/userfaultfd.c | 298 +++++++++++++++++++++++++++++++
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1 file changed, 298 insertions(+)
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diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
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index de2f9ec..dc73021 100644
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--- a/tools/testing/selftests/vm/userfaultfd.c
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+++ b/tools/testing/selftests/vm/userfaultfd.c
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@@ -71,6 +71,304 @@
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#ifdef __NR_userfaultfd
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+/* Linear congruential. */
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+#define TYPE_0 0
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+#define BREAK_0 8
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+#define DEG_0 0
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+#define SEP_0 0
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+
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+/* x**7 + x**3 + 1. */
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+#define TYPE_1 1
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+#define BREAK_1 32
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+#define DEG_1 7
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+#define SEP_1 3
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+
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+/* x**15 + x + 1. */
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+#define TYPE_2 2
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+#define BREAK_2 64
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+#define DEG_2 15
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+#define SEP_2 1
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+
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+/* x**31 + x**3 + 1. */
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+#define TYPE_3 3
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+#define BREAK_3 128
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+#define DEG_3 31
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+#define SEP_3 3
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+
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+/* x**63 + x + 1. */
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+#define TYPE_4 4
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+#define BREAK_4 256
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+#define DEG_4 63
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+#define SEP_4 1
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+
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+/* Array versions of the above information to make code run faster.
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+ Relies on fact that TYPE_i == i. */
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+
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+#define MAX_TYPES 5 /* Max number of types above. */
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+
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+#define __set_errno(val) (errno = (val))
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+
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+struct random_data
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+ {
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+ int32_t *fptr; /* Front pointer. */
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+ int32_t *rptr; /* Rear pointer. */
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+ int32_t *state; /* Array of state values. */
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+ int rand_type; /* Type of random number generator. */
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+ int rand_deg; /* Degree of random number generator. */
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+ int rand_sep; /* Distance between front and rear. */
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+ int32_t *end_ptr; /* Pointer behind state table. */
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+ };
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+
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+struct random_poly_info
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+{
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+ int seps[MAX_TYPES];
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+ int degrees[MAX_TYPES];
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+};
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+
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+static const struct random_poly_info random_poly_info =
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+{
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+ { SEP_0, SEP_1, SEP_2, SEP_3, SEP_4 },
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+ { DEG_0, DEG_1, DEG_2, DEG_3, DEG_4 }
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+};
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+
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+/* If we are using the trivial TYPE_0 R.N.G., just do the old linear
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+ congruential bit. Otherwise, we do our fancy trinomial stuff, which is the
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+ same in all the other cases due to all the global variables that have been
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+ set up. The basic operation is to add the number at the rear pointer into
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+ the one at the front pointer. Then both pointers are advanced to the next
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+ location cyclically in the table. The value returned is the sum generated,
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+ reduced to 31 bits by throwing away the "least random" low bit.
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+ Note: The code takes advantage of the fact that both the front and
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+ rear pointers can't wrap on the same call by not testing the rear
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+ pointer if the front one has wrapped. Returns a 31-bit random number. */
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+
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+int random_r (struct random_data *buf, int32_t *result)
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+{
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+ int32_t *state;
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+
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+ if (buf == NULL || result == NULL)
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+ goto fail;
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+
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+ state = buf->state;
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+
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+ if (buf->rand_type == TYPE_0)
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+ {
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+ int32_t val = ((state[0] * 1103515245U) + 12345U) & 0x7fffffff;
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+ state[0] = val;
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+ *result = val;
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+ }
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+ else
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+ {
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+ int32_t *fptr = buf->fptr;
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+ int32_t *rptr = buf->rptr;
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+ int32_t *end_ptr = buf->end_ptr;
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+ uint32_t val;
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+
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+ val = *fptr += (uint32_t) *rptr;
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+ /* Chucking least random bit. */
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+ *result = val >> 1;
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+ ++fptr;
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+ if (fptr >= end_ptr)
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+ {
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+ fptr = state;
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+ ++rptr;
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+ }
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+ else
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+ {
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+ ++rptr;
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+ if (rptr >= end_ptr)
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+ rptr = state;
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+ }
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+ buf->fptr = fptr;
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+ buf->rptr = rptr;
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+ }
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+ return 0;
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+
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+ fail:
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+ __set_errno (EINVAL);
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+ return -1;
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+}
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+
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+/* Initialize the random number generator based on the given seed. If the
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+ type is the trivial no-state-information type, just remember the seed.
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+ Otherwise, initializes state[] based on the given "seed" via a linear
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+ congruential generator. Then, the pointers are set to known locations
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+ that are exactly rand_sep places apart. Lastly, it cycles the state
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+ information a given number of times to get rid of any initial dependencies
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+ introduced by the L.C.R.N.G. Note that the initialization of randtbl[]
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+ for default usage relies on values produced by this routine. */
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+int srandom_r (unsigned int seed, struct random_data *buf)
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+{
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+ int type;
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+ int32_t *state;
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+ long int i;
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+ int32_t word;
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+ int32_t *dst;
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+ int kc;
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+
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+ if (buf == NULL)
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+ goto fail;
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+ type = buf->rand_type;
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+ if ((unsigned int) type >= MAX_TYPES)
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+ goto fail;
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+
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+ state = buf->state;
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+ /* We must make sure the seed is not 0. Take arbitrarily 1 in this case. */
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+ if (seed == 0)
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+ seed = 1;
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+ state[0] = seed;
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+ if (type == TYPE_0)
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+ goto done;
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+
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+ dst = state;
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+ word = seed;
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+ kc = buf->rand_deg;
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+ for (i = 1; i < kc; ++i)
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+ {
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+ /* This does:
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+ state[i] = (16807 * state[i - 1]) % 2147483647;
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+ but avoids overflowing 31 bits. */
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+ long int hi = word / 127773;
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+ long int lo = word % 127773;
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+ word = 16807 * lo - 2836 * hi;
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+ if (word < 0)
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+ word += 2147483647;
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+ *++dst = word;
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+ }
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+
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+ buf->fptr = &state[buf->rand_sep];
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+ buf->rptr = &state[0];
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+ kc *= 10;
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+ while (--kc >= 0)
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+ {
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+ int32_t discard;
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+ (void) random_r (buf, &discard);
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+ }
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+
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+ done:
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+ return 0;
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+
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+ fail:
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+ return -1;
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+}
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+
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+/* Initialize the state information in the given array of N bytes for
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+ future random number generation. Based on the number of bytes we
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+ are given, and the break values for the different R.N.G.'s, we choose
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+ the best (largest) one we can and set things up for it. srandom is
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+ then called to initialize the state information. Note that on return
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+ from srandom, we set state[-1] to be the type multiplexed with the current
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+ value of the rear pointer; this is so successive calls to initstate won't
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+ lose this information and will be able to restart with setstate.
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+ Note: The first thing we do is save the current state, if any, just like
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+ setstate so that it doesn't matter when initstate is called.
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+ Returns 0 on success, non-zero on failure. */
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+int initstate_r (unsigned int seed, char *arg_state, size_t n,
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+ struct random_data *buf)
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+{
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+ if (buf == NULL)
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+ goto fail;
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+
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+ int32_t *old_state = buf->state;
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+ if (old_state != NULL)
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+ {
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+ int old_type = buf->rand_type;
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+ if (old_type == TYPE_0)
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+ old_state[-1] = TYPE_0;
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+ else
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+ old_state[-1] = (MAX_TYPES * (buf->rptr - old_state)) + old_type;
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+ }
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+
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+ int type;
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+ if (n >= BREAK_3)
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+ type = n < BREAK_4 ? TYPE_3 : TYPE_4;
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+ else if (n < BREAK_1)
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+ {
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+ if (n < BREAK_0)
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+ goto fail;
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+
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+ type = TYPE_0;
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+ }
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+ else
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+ type = n < BREAK_2 ? TYPE_1 : TYPE_2;
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+
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+ int degree = random_poly_info.degrees[type];
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+ int separation = random_poly_info.seps[type];
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+
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+ buf->rand_type = type;
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+ buf->rand_sep = separation;
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+ buf->rand_deg = degree;
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+ int32_t *state = &((int32_t *) arg_state)[1]; /* First location. */
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+ /* Must set END_PTR before srandom. */
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+ buf->end_ptr = &state[degree];
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+
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+ buf->state = state;
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+
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+ srandom_r (seed, buf);
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+
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+ state[-1] = TYPE_0;
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+ if (type != TYPE_0)
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+ state[-1] = (buf->rptr - state) * MAX_TYPES + type;
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+
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+ return 0;
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+
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+ fail:
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+ __set_errno (EINVAL);
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+ return -1;
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+}
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+
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+/* Restore the state from the given state array.
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+ Note: It is important that we also remember the locations of the pointers
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+ in the current state information, and restore the locations of the pointers
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+ from the old state information. This is done by multiplexing the pointer
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+ location into the zeroth word of the state information. Note that due
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+ to the order in which things are done, it is OK to call setstate with the
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+ same state as the current state
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+ Returns 0 on success, non-zero on failure. */
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+int setstate_r (char *arg_state, struct random_data *buf)
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+{
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+ int32_t *new_state = 1 + (int32_t *) arg_state;
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+ int type;
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+ int old_type;
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+ int32_t *old_state;
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+ int degree;
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+ int separation;
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+
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+ if (arg_state == NULL || buf == NULL)
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+ goto fail;
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+
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+ old_type = buf->rand_type;
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+ old_state = buf->state;
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+ if (old_type == TYPE_0)
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+ old_state[-1] = TYPE_0;
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+ else
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+ old_state[-1] = (MAX_TYPES * (buf->rptr - old_state)) + old_type;
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+
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+ type = new_state[-1] % MAX_TYPES;
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+ if (type < TYPE_0 || type > TYPE_4)
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+ goto fail;
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+
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+ buf->rand_deg = degree = random_poly_info.degrees[type];
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+ buf->rand_sep = separation = random_poly_info.seps[type];
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+ buf->rand_type = type;
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+
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+ if (type != TYPE_0)
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+ {
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+ int rear = new_state[-1] / MAX_TYPES;
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+ buf->rptr = &new_state[rear];
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+ buf->fptr = &new_state[(rear + separation) % degree];
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+ }
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+ buf->state = new_state;
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+ /* Set end_ptr too. */
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+ buf->end_ptr = &new_state[degree];
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+
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+ return 0;
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+
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+ fail:
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+ __set_errno (EINVAL);
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+ return -1;
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+}
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+
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static unsigned long nr_cpus, nr_pages, nr_pages_per_cpu, page_size;
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#define BOUNCE_RANDOM (1<<0)
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--
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2.11.0
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