519 lines
11 KiB
C
519 lines
11 KiB
C
// 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;
|
|
}
|
|
|
|
static 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;
|
|
}
|
|
|
|
static 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 obvious 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;
|
|
}
|
|
|
|
static 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");
|