--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Tests for Generic Reed Solomon encoder / decoder library
+ *
+ * Written by Ferdinand Blomqvist
+ * Based on previous work by Phil Karn, KA9Q
+ */
+#include <linux/rslib.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+
+enum verbosity {
+ V_SILENT,
+ V_PROGRESS,
+ V_CSUMMARY
+};
+
+enum method {
+ CORR_BUFFER,
+ CALLER_SYNDROME,
+ IN_PLACE
+};
+
+#define __param(type, name, init, msg) \
+ static type name = init; \
+ module_param(name, type, 0444); \
+ MODULE_PARM_DESC(name, msg)
+
+__param(int, v, V_PROGRESS, "Verbosity level");
+__param(int, ewsc, 1, "Erasures without symbol corruption");
+__param(int, bc, 1, "Test for correct behaviour beyond error correction capacity");
+
+struct etab {
+ int symsize;
+ int genpoly;
+ int fcs;
+ int prim;
+ int nroots;
+ int ntrials;
+};
+
+/* List of codes to test */
+static struct etab Tab[] = {
+ {2, 0x7, 1, 1, 1, 100000 },
+ {3, 0xb, 1, 1, 2, 100000 },
+ {3, 0xb, 1, 1, 3, 100000 },
+ {3, 0xb, 2, 1, 4, 100000 },
+ {4, 0x13, 1, 1, 4, 10000 },
+ {5, 0x25, 1, 1, 6, 1000 },
+ {6, 0x43, 3, 1, 8, 1000 },
+ {7, 0x89, 1, 1, 14, 500 },
+ {8, 0x11d, 1, 1, 30, 100 },
+ {8, 0x187, 112, 11, 32, 100 },
+ {9, 0x211, 1, 1, 33, 80 },
+ {0, 0, 0, 0, 0, 0},
+};
+
+
+struct estat {
+ int dwrong;
+ int irv;
+ int wepos;
+ int nwords;
+};
+
+struct bcstat {
+ int rfail;
+ int rsuccess;
+ int noncw;
+ int nwords;
+};
+
+struct wspace {
+ uint16_t *c; /* sent codeword */
+ uint16_t *r; /* received word */
+ uint16_t *s; /* syndrome */
+ uint16_t *corr; /* correction buffer */
+ int *errlocs;
+ int *derrlocs;
+};
+
+struct pad {
+ int mult;
+ int shift;
+};
+
+static struct pad pad_coef[] = {
+ { 0, 0 },
+ { 1, 2 },
+ { 1, 1 },
+ { 3, 2 },
+ { 1, 0 },
+};
+
+static void free_ws(struct wspace *ws)
+{
+ if (!ws)
+ return;
+
+ kfree(ws->errlocs);
+ kfree(ws->c);
+ kfree(ws);
+}
+
+static struct wspace *alloc_ws(struct rs_codec *rs)
+{
+ int nroots = rs->nroots;
+ struct wspace *ws;
+ int nn = rs->nn;
+
+ ws = kzalloc(sizeof(*ws), GFP_KERNEL);
+ if (!ws)
+ return NULL;
+
+ ws->c = kmalloc_array(2 * (nn + nroots),
+ sizeof(uint16_t), GFP_KERNEL);
+ if (!ws->c)
+ goto err;
+
+ ws->r = ws->c + nn;
+ ws->s = ws->r + nn;
+ ws->corr = ws->s + nroots;
+
+ ws->errlocs = kmalloc_array(nn + nroots, sizeof(int), GFP_KERNEL);
+ if (!ws->errlocs)
+ goto err;
+
+ ws->derrlocs = ws->errlocs + nn;
+ return ws;
+
+err:
+ free_ws(ws);
+ return NULL;
+}
+
+
+/*
+ * Generates a random codeword and stores it in c. Generates random errors and
+ * erasures, and stores the random word with errors in r. Erasure positions are
+ * stored in derrlocs, while errlocs has one of three values in every position:
+ *
+ * 0 if there is no error in this position;
+ * 1 if there is a symbol error in this position;
+ * 2 if there is an erasure without symbol corruption.
+ *
+ * Returns the number of corrupted symbols.
+ */
+static int get_rcw_we(struct rs_control *rs, struct wspace *ws,
+ int len, int errs, int eras)
+{
+ int nroots = rs->codec->nroots;
+ int *derrlocs = ws->derrlocs;
+ int *errlocs = ws->errlocs;
+ int dlen = len - nroots;
+ int nn = rs->codec->nn;
+ uint16_t *c = ws->c;
+ uint16_t *r = ws->r;
+ int errval;
+ int errloc;
+ int i;
+
+ /* Load c with random data and encode */
+ for (i = 0; i < dlen; i++)
+ c[i] = prandom_u32() & nn;
+
+ memset(c + dlen, 0, nroots * sizeof(*c));
+ encode_rs16(rs, c, dlen, c + dlen, 0);
+
+ /* Make copyand add errors and erasures */
+ memcpy(r, c, len * sizeof(*r));
+ memset(errlocs, 0, len * sizeof(*errlocs));
+ memset(derrlocs, 0, nroots * sizeof(*derrlocs));
+
+ /* Generating random errors */
+ for (i = 0; i < errs; i++) {
+ do {
+ /* Error value must be nonzero */
+ errval = prandom_u32() & nn;
+ } while (errval == 0);
+
+ do {
+ /* Must not choose the same location twice */
+ errloc = prandom_u32() % len;
+ } while (errlocs[errloc] != 0);
+
+ errlocs[errloc] = 1;
+ r[errloc] ^= errval;
+ }
+
+ /* Generating random erasures */
+ for (i = 0; i < eras; i++) {
+ do {
+ /* Must not choose the same location twice */
+ errloc = prandom_u32() % len;
+ } while (errlocs[errloc] != 0);
+
+ derrlocs[i] = errloc;
+
+ if (ewsc && (prandom_u32() & 1)) {
+ /* Erasure with the symbol intact */
+ errlocs[errloc] = 2;
+ } else {
+ /* Erasure with corrupted symbol */
+ do {
+ /* Error value must be nonzero */
+ errval = prandom_u32() & nn;
+ } while (errval == 0);
+
+ errlocs[errloc] = 1;
+ r[errloc] ^= errval;
+ errs++;
+ }
+ }
+
+ return errs;
+}
+
+static void fix_err(uint16_t *data, int nerrs, uint16_t *corr, int *errlocs)
+{
+ int i;
+
+ for (i = 0; i < nerrs; i++)
+ data[errlocs[i]] ^= corr[i];
+}
+
+static void compute_syndrome(struct rs_control *rsc, uint16_t *data,
+ int len, uint16_t *syn)
+{
+ struct rs_codec *rs = rsc->codec;
+ uint16_t *alpha_to = rs->alpha_to;
+ uint16_t *index_of = rs->index_of;
+ int nroots = rs->nroots;
+ int prim = rs->prim;
+ int fcr = rs->fcr;
+ int i, j;
+
+ /* Calculating syndrome */
+ for (i = 0; i < nroots; i++) {
+ syn[i] = data[0];
+ for (j = 1; j < len; j++) {
+ if (syn[i] == 0) {
+ syn[i] = data[j];
+ } else {
+ syn[i] = data[j] ^
+ alpha_to[rs_modnn(rs, index_of[syn[i]]
+ + (fcr + i) * prim)];
+ }
+ }
+ }
+
+ /* Convert to index form */
+ for (i = 0; i < nroots; i++)
+ syn[i] = rs->index_of[syn[i]];
+}
+
+/* Test up to error correction capacity */
+static void test_uc(struct rs_control *rs, int len, int errs,
+ int eras, int trials, struct estat *stat,
+ struct wspace *ws, int method)
+{
+ int dlen = len - rs->codec->nroots;
+ int *derrlocs = ws->derrlocs;
+ int *errlocs = ws->errlocs;
+ uint16_t *corr = ws->corr;
+ uint16_t *c = ws->c;
+ uint16_t *r = ws->r;
+ uint16_t *s = ws->s;
+ int derrs, nerrs;
+ int i, j;
+
+ for (j = 0; j < trials; j++) {
+ nerrs = get_rcw_we(rs, ws, len, errs, eras);
+
+ switch (method) {
+ case CORR_BUFFER:
+ derrs = decode_rs16(rs, r, r + dlen, dlen,
+ NULL, eras, derrlocs, 0, corr);
+ fix_err(r, derrs, corr, derrlocs);
+ break;
+ case CALLER_SYNDROME:
+ compute_syndrome(rs, r, len, s);
+ derrs = decode_rs16(rs, NULL, NULL, dlen,
+ s, eras, derrlocs, 0, corr);
+ fix_err(r, derrs, corr, derrlocs);
+ break;
+ case IN_PLACE:
+ derrs = decode_rs16(rs, r, r + dlen, dlen,
+ NULL, eras, derrlocs, 0, NULL);
+ break;
+ default:
+ continue;
+ }
+
+ if (derrs != nerrs)
+ stat->irv++;
+
+ if (method != IN_PLACE) {
+ for (i = 0; i < derrs; i++) {
+ if (errlocs[derrlocs[i]] != 1)
+ stat->wepos++;
+ }
+ }
+
+ if (memcmp(r, c, len * sizeof(*r)))
+ stat->dwrong++;
+ }
+ stat->nwords += trials;
+}
+
+int ex_rs_helper(struct rs_control *rs, struct wspace *ws,
+ int len, int trials, int method)
+{
+ static const char * const desc[] = {
+ "Testing correction buffer interface...",
+ "Testing with caller provided syndrome...",
+ "Testing in-place interface..."
+ };
+
+ struct estat stat = {0, 0, 0, 0};
+ int nroots = rs->codec->nroots;
+ int errs, eras, retval;
+
+ if (v >= V_PROGRESS)
+ pr_info(" %s\n", desc[method]);
+
+ for (errs = 0; errs <= nroots / 2; errs++)
+ for (eras = 0; eras <= nroots - 2 * errs; eras++)
+ test_uc(rs, len, errs, eras, trials, &stat, ws, method);
+
+ if (v >= V_CSUMMARY) {
+ pr_info(" Decodes wrong: %d / %d\n",
+ stat.dwrong, stat.nwords);
+ pr_info(" Wrong return value: %d / %d\n",
+ stat.irv, stat.nwords);
+ if (method != IN_PLACE)
+ pr_info(" Wrong error position: %d\n", stat.wepos);
+ }
+
+ retval = stat.dwrong + stat.wepos + stat.irv;
+ if (retval && v >= V_PROGRESS)
+ pr_warn(" FAIL: %d decoding failures!\n", retval);
+
+ return retval;
+}
+
+int exercise_rs(struct rs_control *rs, struct wspace *ws,
+ int len, int trials)
+{
+
+ int retval = 0;
+ int i;
+
+ if (v >= V_PROGRESS)
+ pr_info("Testing up to error correction capacity...\n");
+
+ for (i = 0; i <= IN_PLACE; i++)
+ retval |= ex_rs_helper(rs, ws, len, trials, i);
+
+ return retval;
+}
+
+/* Tests for correct behaviour beyond error correction capacity */
+static void test_bc(struct rs_control *rs, int len, int errs,
+ int eras, int trials, struct bcstat *stat,
+ struct wspace *ws)
+{
+ int nroots = rs->codec->nroots;
+ int dlen = len - nroots;
+ int *derrlocs = ws->derrlocs;
+ uint16_t *corr = ws->corr;
+ uint16_t *r = ws->r;
+ int derrs, j;
+
+ for (j = 0; j < trials; j++) {
+ get_rcw_we(rs, ws, len, errs, eras);
+ derrs = decode_rs16(rs, r, r + dlen, dlen,
+ NULL, eras, derrlocs, 0, corr);
+ fix_err(r, derrs, corr, derrlocs);
+
+ if (derrs >= 0) {
+ stat->rsuccess++;
+
+ /*
+ * We check that the returned word is actually a
+ * codeword. The obious way to do this would be to
+ * compute the syndrome, but we don't want to replicate
+ * that code here. However, all the codes are in
+ * systematic form, and therefore we can encode the
+ * returned word, and see whether the parity changes or
+ * not.
+ */
+ memset(corr, 0, nroots * sizeof(*corr));
+ encode_rs16(rs, r, dlen, corr, 0);
+
+ if (memcmp(r + dlen, corr, nroots * sizeof(*corr)))
+ stat->noncw++;
+ } else {
+ stat->rfail++;
+ }
+ }
+ stat->nwords += trials;
+}
+
+int exercise_rs_bc(struct rs_control *rs, struct wspace *ws,
+ int len, int trials)
+{
+ struct bcstat stat = {0, 0, 0, 0};
+ int nroots = rs->codec->nroots;
+ int errs, eras, cutoff;
+
+ if (v >= V_PROGRESS)
+ pr_info("Testing beyond error correction capacity...\n");
+
+ for (errs = 1; errs <= nroots; errs++) {
+ eras = nroots - 2 * errs + 1;
+ if (eras < 0)
+ eras = 0;
+
+ cutoff = nroots <= len - errs ? nroots : len - errs;
+ for (; eras <= cutoff; eras++)
+ test_bc(rs, len, errs, eras, trials, &stat, ws);
+ }
+
+ if (v >= V_CSUMMARY) {
+ pr_info(" decoder gives up: %d / %d\n",
+ stat.rfail, stat.nwords);
+ pr_info(" decoder returns success: %d / %d\n",
+ stat.rsuccess, stat.nwords);
+ pr_info(" not a codeword: %d / %d\n",
+ stat.noncw, stat.rsuccess);
+ }
+
+ if (stat.noncw && v >= V_PROGRESS)
+ pr_warn(" FAIL: %d silent failures!\n", stat.noncw);
+
+ return stat.noncw;
+}
+
+static int run_exercise(struct etab *e)
+{
+ int nn = (1 << e->symsize) - 1;
+ int kk = nn - e->nroots;
+ struct rs_control *rsc;
+ int retval = -ENOMEM;
+ int max_pad = kk - 1;
+ int prev_pad = -1;
+ struct wspace *ws;
+ int i;
+
+ rsc = init_rs(e->symsize, e->genpoly, e->fcs, e->prim, e->nroots);
+ if (!rsc)
+ return retval;
+
+ ws = alloc_ws(rsc->codec);
+ if (!ws)
+ goto err;
+
+ retval = 0;
+ for (i = 0; i < ARRAY_SIZE(pad_coef); i++) {
+ int pad = (pad_coef[i].mult * max_pad) >> pad_coef[i].shift;
+ int len = nn - pad;
+
+ if (pad == prev_pad)
+ continue;
+
+ prev_pad = pad;
+ if (v >= V_PROGRESS) {
+ pr_info("Testing (%d,%d)_%d code...\n",
+ len, kk - pad, nn + 1);
+ }
+
+ retval |= exercise_rs(rsc, ws, len, e->ntrials);
+ if (bc)
+ retval |= exercise_rs_bc(rsc, ws, len, e->ntrials);
+ }
+
+ free_ws(ws);
+
+err:
+ free_rs(rsc);
+ return retval;
+}
+
+static int __init test_rslib_init(void)
+{
+ int i, fail = 0;
+
+ for (i = 0; Tab[i].symsize != 0 ; i++) {
+ int retval;
+
+ retval = run_exercise(Tab + i);
+ if (retval < 0)
+ return -ENOMEM;
+
+ fail |= retval;
+ }
+
+ if (fail)
+ pr_warn("rslib: test failed\n");
+ else
+ pr_info("rslib: test ok\n");
+
+ return -EAGAIN; /* Fail will directly unload the module */
+}
+
+static void __exit test_rslib_exit(void)
+{
+}
+
+module_init(test_rslib_init)
+module_exit(test_rslib_exit)
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Ferdinand Blomqvist");
+MODULE_DESCRIPTION("Reed-Solomon library test");
projects / linux-2.6-block.git / blobdiff