scratch: replace frames with "checkpoint" system
This commit is contained in:
Andrew Poelstra
parent
7623cf2b97
commit
98836b11f0
|
|
@ -653,15 +653,13 @@ static int secp256k1_ecmult_strauss_batch(const secp256k1_callback* error_callba
|
|||
secp256k1_scalar* scalars;
|
||||
struct secp256k1_strauss_state state;
|
||||
size_t i;
|
||||
const size_t scratch_checkpoint = secp256k1_scratch_checkpoint(error_callback, scratch);
|
||||
|
||||
secp256k1_gej_set_infinity(r);
|
||||
if (inp_g_sc == NULL && n_points == 0) {
|
||||
return 1;
|
||||
}
|
||||
|
||||
if (!secp256k1_scratch_allocate_frame(error_callback, scratch, secp256k1_strauss_scratch_size(n_points), STRAUSS_SCRATCH_OBJECTS)) {
|
||||
return 0;
|
||||
}
|
||||
points = (secp256k1_gej*)secp256k1_scratch_alloc(error_callback, scratch, n_points * sizeof(secp256k1_gej));
|
||||
scalars = (secp256k1_scalar*)secp256k1_scratch_alloc(error_callback, scratch, n_points * sizeof(secp256k1_scalar));
|
||||
state.prej = (secp256k1_gej*)secp256k1_scratch_alloc(error_callback, scratch, n_points * ECMULT_TABLE_SIZE(WINDOW_A) * sizeof(secp256k1_gej));
|
||||
|
|
@ -674,16 +672,21 @@ static int secp256k1_ecmult_strauss_batch(const secp256k1_callback* error_callba
|
|||
#endif
|
||||
state.ps = (struct secp256k1_strauss_point_state*)secp256k1_scratch_alloc(error_callback, scratch, n_points * sizeof(struct secp256k1_strauss_point_state));
|
||||
|
||||
if (points == NULL || scalars == NULL || state.prej == NULL || state.zr == NULL || state.pre_a == NULL) {
|
||||
secp256k1_scratch_apply_checkpoint(error_callback, scratch, scratch_checkpoint);
|
||||
return 0;
|
||||
}
|
||||
|
||||
for (i = 0; i < n_points; i++) {
|
||||
secp256k1_ge point;
|
||||
if (!cb(&scalars[i], &point, i+cb_offset, cbdata)) {
|
||||
secp256k1_scratch_deallocate_frame(error_callback, scratch);
|
||||
secp256k1_scratch_apply_checkpoint(error_callback, scratch, scratch_checkpoint);
|
||||
return 0;
|
||||
}
|
||||
secp256k1_gej_set_ge(&points[i], &point);
|
||||
}
|
||||
secp256k1_ecmult_strauss_wnaf(ctx, &state, r, n_points, points, scalars, inp_g_sc);
|
||||
secp256k1_scratch_deallocate_frame(error_callback, scratch);
|
||||
secp256k1_scratch_apply_checkpoint(error_callback, scratch, scratch_checkpoint);
|
||||
return 1;
|
||||
}
|
||||
|
||||
|
|
@ -986,6 +989,7 @@ static size_t secp256k1_pippenger_scratch_size(size_t n_points, int bucket_windo
|
|||
}
|
||||
|
||||
static int secp256k1_ecmult_pippenger_batch(const secp256k1_callback* error_callback, const secp256k1_ecmult_context *ctx, secp256k1_scratch *scratch, secp256k1_gej *r, const secp256k1_scalar *inp_g_sc, secp256k1_ecmult_multi_callback cb, void *cbdata, size_t n_points, size_t cb_offset) {
|
||||
const size_t scratch_checkpoint = secp256k1_scratch_checkpoint(error_callback, scratch);
|
||||
/* Use 2(n+1) with the endomorphism, n+1 without, when calculating batch
|
||||
* sizes. The reason for +1 is that we add the G scalar to the list of
|
||||
* other scalars. */
|
||||
|
|
@ -1010,15 +1014,21 @@ static int secp256k1_ecmult_pippenger_batch(const secp256k1_callback* error_call
|
|||
}
|
||||
|
||||
bucket_window = secp256k1_pippenger_bucket_window(n_points);
|
||||
if (!secp256k1_scratch_allocate_frame(error_callback, scratch, secp256k1_pippenger_scratch_size(n_points, bucket_window), PIPPENGER_SCRATCH_OBJECTS)) {
|
||||
return 0;
|
||||
}
|
||||
points = (secp256k1_ge *) secp256k1_scratch_alloc(error_callback, scratch, entries * sizeof(*points));
|
||||
scalars = (secp256k1_scalar *) secp256k1_scratch_alloc(error_callback, scratch, entries * sizeof(*scalars));
|
||||
state_space = (struct secp256k1_pippenger_state *) secp256k1_scratch_alloc(error_callback, scratch, sizeof(*state_space));
|
||||
if (points == NULL || scalars == NULL || state_space == NULL) {
|
||||
secp256k1_scratch_apply_checkpoint(error_callback, scratch, scratch_checkpoint);
|
||||
return 0;
|
||||
}
|
||||
|
||||
state_space->ps = (struct secp256k1_pippenger_point_state *) secp256k1_scratch_alloc(error_callback, scratch, entries * sizeof(*state_space->ps));
|
||||
state_space->wnaf_na = (int *) secp256k1_scratch_alloc(error_callback, scratch, entries*(WNAF_SIZE(bucket_window+1)) * sizeof(int));
|
||||
buckets = (secp256k1_gej *) secp256k1_scratch_alloc(error_callback, scratch, (1<<bucket_window) * sizeof(*buckets));
|
||||
if (state_space->ps == NULL || state_space->wnaf_na == NULL || buckets == NULL) {
|
||||
secp256k1_scratch_apply_checkpoint(error_callback, scratch, scratch_checkpoint);
|
||||
return 0;
|
||||
}
|
||||
|
||||
if (inp_g_sc != NULL) {
|
||||
scalars[0] = *inp_g_sc;
|
||||
|
|
@ -1032,7 +1042,7 @@ static int secp256k1_ecmult_pippenger_batch(const secp256k1_callback* error_call
|
|||
|
||||
while (point_idx < n_points) {
|
||||
if (!cb(&scalars[idx], &points[idx], point_idx + cb_offset, cbdata)) {
|
||||
secp256k1_scratch_deallocate_frame(error_callback, scratch);
|
||||
secp256k1_scratch_apply_checkpoint(error_callback, scratch, scratch_checkpoint);
|
||||
return 0;
|
||||
}
|
||||
idx++;
|
||||
|
|
@ -1056,7 +1066,7 @@ static int secp256k1_ecmult_pippenger_batch(const secp256k1_callback* error_call
|
|||
for(i = 0; i < 1<<bucket_window; i++) {
|
||||
secp256k1_gej_clear(&buckets[i]);
|
||||
}
|
||||
secp256k1_scratch_deallocate_frame(error_callback, scratch);
|
||||
secp256k1_scratch_apply_checkpoint(error_callback, scratch, scratch_checkpoint);
|
||||
return 1;
|
||||
}
|
||||
|
||||
|
|
|
|||
|
|
@ -7,17 +7,17 @@
|
|||
#ifndef _SECP256K1_SCRATCH_
|
||||
#define _SECP256K1_SCRATCH_
|
||||
|
||||
#define SECP256K1_SCRATCH_MAX_FRAMES 5
|
||||
|
||||
/* The typedef is used internally; the struct name is used in the public API
|
||||
* (where it is exposed as a different typedef) */
|
||||
typedef struct secp256k1_scratch_space_struct {
|
||||
/** guard against interpreting this object as other types */
|
||||
unsigned char magic[8];
|
||||
/** actual allocated data */
|
||||
void *data;
|
||||
void *current_frame;
|
||||
size_t offset[SECP256K1_SCRATCH_MAX_FRAMES];
|
||||
size_t frame_size[SECP256K1_SCRATCH_MAX_FRAMES];
|
||||
size_t frame;
|
||||
/** amount that has been allocated (i.e. `data + offset` is the next
|
||||
* available pointer) */
|
||||
size_t alloc_size;
|
||||
/** maximum size available to allocate */
|
||||
size_t max_size;
|
||||
} secp256k1_scratch;
|
||||
|
||||
|
|
@ -25,11 +25,13 @@ static secp256k1_scratch* secp256k1_scratch_create(const secp256k1_callback* err
|
|||
|
||||
static void secp256k1_scratch_destroy(const secp256k1_callback* error_callback, secp256k1_scratch* scratch);
|
||||
|
||||
/** Attempts to allocate a new stack frame with `n` available bytes. Returns 1 on success, 0 on failure */
|
||||
static int secp256k1_scratch_allocate_frame(const secp256k1_callback* error_callback, secp256k1_scratch* scratch, size_t n, size_t objects);
|
||||
/** Returns an opaque object used to "checkpoint" a scratch space. Used
|
||||
* with `secp256k1_scratch_apply_checkpoint` to undo allocations. */
|
||||
static size_t secp256k1_scratch_checkpoint(const secp256k1_callback* error_callback, const secp256k1_scratch* scratch);
|
||||
|
||||
/** Deallocates a stack frame */
|
||||
static void secp256k1_scratch_deallocate_frame(const secp256k1_callback* error_callback, secp256k1_scratch* scratch);
|
||||
/** Applies a check point received from `secp256k1_scratch_checkpoint`,
|
||||
* undoing all allocations since that point. */
|
||||
static void secp256k1_scratch_apply_checkpoint(const secp256k1_callback* error_callback, secp256k1_scratch* scratch, size_t checkpoint);
|
||||
|
||||
/** Returns the maximum allocation the scratch space will allow */
|
||||
static size_t secp256k1_scratch_max_allocation(const secp256k1_callback* error_callback, const secp256k1_scratch* scratch, size_t n_objects);
|
||||
|
|
|
|||
|
|
@ -25,7 +25,7 @@ static secp256k1_scratch* secp256k1_scratch_create(const secp256k1_callback* err
|
|||
|
||||
static void secp256k1_scratch_destroy(const secp256k1_callback* error_callback, secp256k1_scratch* scratch) {
|
||||
if (scratch != NULL) {
|
||||
VERIFY_CHECK(scratch->frame == 0);
|
||||
VERIFY_CHECK(scratch->alloc_size == 0); /* all checkpoints should be applied */
|
||||
if (memcmp(scratch->magic, "scratch", 8) != 0) {
|
||||
secp256k1_callback_call(error_callback, "invalid scratch space");
|
||||
return;
|
||||
|
|
@ -35,58 +35,39 @@ static void secp256k1_scratch_destroy(const secp256k1_callback* error_callback,
|
|||
}
|
||||
}
|
||||
|
||||
static size_t secp256k1_scratch_max_allocation(const secp256k1_callback* error_callback, const secp256k1_scratch* scratch, size_t objects) {
|
||||
size_t i = 0;
|
||||
size_t allocated = 0;
|
||||
static size_t secp256k1_scratch_checkpoint(const secp256k1_callback* error_callback, const secp256k1_scratch* scratch) {
|
||||
if (memcmp(scratch->magic, "scratch", 8) != 0) {
|
||||
secp256k1_callback_call(error_callback, "invalid scratch space");
|
||||
return 0;
|
||||
}
|
||||
for (i = 0; i < scratch->frame; i++) {
|
||||
allocated += scratch->frame_size[i];
|
||||
}
|
||||
if (scratch->max_size - allocated <= objects * (ALIGNMENT - 1)) {
|
||||
return 0;
|
||||
}
|
||||
return scratch->max_size - allocated - objects * (ALIGNMENT - 1);
|
||||
return scratch->alloc_size;
|
||||
}
|
||||
|
||||
static int secp256k1_scratch_allocate_frame(const secp256k1_callback* error_callback, secp256k1_scratch* scratch, size_t n, size_t objects) {
|
||||
VERIFY_CHECK(scratch->frame < SECP256K1_SCRATCH_MAX_FRAMES);
|
||||
|
||||
if (memcmp(scratch->magic, "scratch", 8) != 0) {
|
||||
secp256k1_callback_call(error_callback, "invalid scratch space");
|
||||
return 0;
|
||||
}
|
||||
|
||||
if (n <= secp256k1_scratch_max_allocation(error_callback, scratch, objects)) {
|
||||
n += objects * (ALIGNMENT - 1);
|
||||
scratch->current_frame = scratch->data;
|
||||
scratch->data = (void *) ((char *) scratch->data + n);
|
||||
scratch->frame_size[scratch->frame] = n;
|
||||
scratch->offset[scratch->frame] = 0;
|
||||
scratch->frame++;
|
||||
return 1;
|
||||
} else {
|
||||
return 0;
|
||||
}
|
||||
}
|
||||
|
||||
static void secp256k1_scratch_deallocate_frame(const secp256k1_callback* error_callback, secp256k1_scratch* scratch) {
|
||||
static void secp256k1_scratch_apply_checkpoint(const secp256k1_callback* error_callback, secp256k1_scratch* scratch, size_t checkpoint) {
|
||||
if (memcmp(scratch->magic, "scratch", 8) != 0) {
|
||||
secp256k1_callback_call(error_callback, "invalid scratch space");
|
||||
return;
|
||||
}
|
||||
if (checkpoint > scratch->alloc_size) {
|
||||
secp256k1_callback_call(error_callback, "invalid checkpoint");
|
||||
return;
|
||||
}
|
||||
scratch->alloc_size = checkpoint;
|
||||
}
|
||||
|
||||
VERIFY_CHECK(scratch->frame > 0);
|
||||
|
||||
scratch->frame--;
|
||||
scratch->data = (void *) ((char *) scratch->data - scratch->frame_size[scratch->frame]);
|
||||
static size_t secp256k1_scratch_max_allocation(const secp256k1_callback* error_callback, const secp256k1_scratch* scratch, size_t objects) {
|
||||
if (memcmp(scratch->magic, "scratch", 8) != 0) {
|
||||
secp256k1_callback_call(error_callback, "invalid scratch space");
|
||||
return 0;
|
||||
}
|
||||
if (scratch->max_size - scratch->alloc_size <= objects * (ALIGNMENT - 1)) {
|
||||
return 0;
|
||||
}
|
||||
return scratch->max_size - scratch->alloc_size - objects * (ALIGNMENT - 1);
|
||||
}
|
||||
|
||||
static void *secp256k1_scratch_alloc(const secp256k1_callback* error_callback, secp256k1_scratch* scratch, size_t size) {
|
||||
void *ret;
|
||||
size_t frame = scratch->frame - 1;
|
||||
size = ROUND_TO_ALIGN(size);
|
||||
|
||||
if (memcmp(scratch->magic, "scratch", 8) != 0) {
|
||||
|
|
@ -94,12 +75,12 @@ static void *secp256k1_scratch_alloc(const secp256k1_callback* error_callback, s
|
|||
return NULL;
|
||||
}
|
||||
|
||||
if (scratch->frame == 0 || size + scratch->offset[frame] > scratch->frame_size[frame]) {
|
||||
if (size > scratch->max_size - scratch->alloc_size) {
|
||||
return NULL;
|
||||
}
|
||||
ret = (void *) ((char *) scratch->current_frame + scratch->offset[frame]);
|
||||
ret = (void *) ((char *) scratch->data + scratch->alloc_size);
|
||||
memset(ret, 0, size);
|
||||
scratch->offset[frame] += size;
|
||||
scratch->alloc_size += size;
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
|
|
|||
69
src/tests.c
69
src/tests.c
|
|
@ -333,7 +333,11 @@ void run_context_tests(int use_prealloc) {
|
|||
}
|
||||
|
||||
void run_scratch_tests(void) {
|
||||
const size_t adj_alloc = ((500 + ALIGNMENT - 1) / ALIGNMENT) * ALIGNMENT;
|
||||
|
||||
int32_t ecount = 0;
|
||||
size_t checkpoint;
|
||||
size_t checkpoint_2;
|
||||
secp256k1_context *none = secp256k1_context_create(SECP256K1_CONTEXT_NONE);
|
||||
secp256k1_scratch_space *scratch;
|
||||
secp256k1_scratch_space local_scratch;
|
||||
|
|
@ -348,43 +352,54 @@ void run_scratch_tests(void) {
|
|||
|
||||
/* Test internal API */
|
||||
CHECK(secp256k1_scratch_max_allocation(&none->error_callback, scratch, 0) == 1000);
|
||||
CHECK(secp256k1_scratch_max_allocation(&none->error_callback, scratch, 1) < 1000);
|
||||
CHECK(secp256k1_scratch_max_allocation(&none->error_callback, scratch, 1) == 1000 - (ALIGNMENT - 1));
|
||||
CHECK(scratch->alloc_size == 0);
|
||||
CHECK(scratch->alloc_size % ALIGNMENT == 0);
|
||||
|
||||
/* Allocating 500 bytes with no frame fails */
|
||||
CHECK(secp256k1_scratch_alloc(&none->error_callback, scratch, 500) == NULL);
|
||||
CHECK(secp256k1_scratch_max_allocation(&none->error_callback, scratch, 0) == 1000);
|
||||
|
||||
/* ...but pushing a new stack frame does affect the max allocation */
|
||||
CHECK(secp256k1_scratch_allocate_frame(&none->error_callback, scratch, 500, 1) == 1);
|
||||
CHECK(secp256k1_scratch_max_allocation(&none->error_callback, scratch, 1) < 500); /* 500 - (ALIGNMENT - 1) */
|
||||
/* Allocating 500 bytes succeeds */
|
||||
checkpoint = secp256k1_scratch_checkpoint(&none->error_callback, scratch);
|
||||
CHECK(secp256k1_scratch_alloc(&none->error_callback, scratch, 500) != NULL);
|
||||
CHECK(secp256k1_scratch_max_allocation(&none->error_callback, scratch, 0) == 1000 - adj_alloc);
|
||||
CHECK(secp256k1_scratch_max_allocation(&none->error_callback, scratch, 1) == 1000 - adj_alloc - (ALIGNMENT - 1));
|
||||
CHECK(scratch->alloc_size != 0);
|
||||
CHECK(scratch->alloc_size % ALIGNMENT == 0);
|
||||
|
||||
/* Allocating another 500 bytes fails */
|
||||
CHECK(secp256k1_scratch_alloc(&none->error_callback, scratch, 500) == NULL);
|
||||
CHECK(secp256k1_scratch_max_allocation(&none->error_callback, scratch, 0) == 1000 - adj_alloc);
|
||||
CHECK(secp256k1_scratch_max_allocation(&none->error_callback, scratch, 1) == 1000 - adj_alloc - (ALIGNMENT - 1));
|
||||
CHECK(scratch->alloc_size != 0);
|
||||
CHECK(scratch->alloc_size % ALIGNMENT == 0);
|
||||
|
||||
CHECK(secp256k1_scratch_allocate_frame(&none->error_callback, scratch, 500, 1) == 0);
|
||||
|
||||
/* ...and this effect is undone by popping the frame */
|
||||
secp256k1_scratch_deallocate_frame(&none->error_callback, scratch);
|
||||
/* ...but it succeeds once we apply the checkpoint to undo it */
|
||||
secp256k1_scratch_apply_checkpoint(&none->error_callback, scratch, checkpoint);
|
||||
CHECK(scratch->alloc_size == 0);
|
||||
CHECK(secp256k1_scratch_max_allocation(&none->error_callback, scratch, 0) == 1000);
|
||||
CHECK(secp256k1_scratch_alloc(&none->error_callback, scratch, 500) == NULL);
|
||||
CHECK(secp256k1_scratch_alloc(&none->error_callback, scratch, 500) != NULL);
|
||||
CHECK(scratch->alloc_size != 0);
|
||||
|
||||
/* cleanup */
|
||||
secp256k1_scratch_space_destroy(none, scratch);
|
||||
/* try to apply a bad checkpoint */
|
||||
checkpoint_2 = secp256k1_scratch_checkpoint(&none->error_callback, scratch);
|
||||
secp256k1_scratch_apply_checkpoint(&none->error_callback, scratch, checkpoint);
|
||||
CHECK(ecount == 0);
|
||||
secp256k1_scratch_apply_checkpoint(&none->error_callback, scratch, checkpoint_2); /* checkpoint_2 is after checkpoint */
|
||||
CHECK(ecount == 1);
|
||||
secp256k1_scratch_apply_checkpoint(&none->error_callback, scratch, (size_t) -1); /* this is just wildly invalid */
|
||||
CHECK(ecount == 2);
|
||||
|
||||
/* try to use badly initialized scratch space */
|
||||
secp256k1_scratch_space_destroy(none, scratch);
|
||||
memset(&local_scratch, 0, sizeof(local_scratch));
|
||||
scratch = &local_scratch;
|
||||
CHECK(!secp256k1_scratch_max_allocation(&none->error_callback, scratch, 0));
|
||||
CHECK(ecount == 1);
|
||||
CHECK(secp256k1_scratch_allocate_frame(&none->error_callback, scratch, 500, 1) == 0);
|
||||
CHECK(ecount == 2);
|
||||
CHECK(secp256k1_scratch_alloc(&none->error_callback, scratch, 500) == NULL);
|
||||
CHECK(ecount == 3);
|
||||
secp256k1_scratch_deallocate_frame(&none->error_callback, scratch);
|
||||
CHECK(secp256k1_scratch_alloc(&none->error_callback, scratch, 500) == NULL);
|
||||
CHECK(ecount == 4);
|
||||
secp256k1_scratch_space_destroy(none, scratch);
|
||||
CHECK(ecount == 5);
|
||||
|
||||
/* cleanup */
|
||||
secp256k1_scratch_space_destroy(none, NULL); /* no-op */
|
||||
secp256k1_context_destroy(none);
|
||||
}
|
||||
|
||||
|
|
@ -2946,16 +2961,26 @@ void test_ecmult_multi_pippenger_max_points(void) {
|
|||
int bucket_window = 0;
|
||||
|
||||
for(; scratch_size < max_size; scratch_size+=256) {
|
||||
size_t i;
|
||||
size_t total_alloc;
|
||||
size_t checkpoint;
|
||||
scratch = secp256k1_scratch_create(&ctx->error_callback, scratch_size);
|
||||
CHECK(scratch != NULL);
|
||||
checkpoint = secp256k1_scratch_checkpoint(&ctx->error_callback, scratch);
|
||||
n_points_supported = secp256k1_pippenger_max_points(&ctx->error_callback, scratch);
|
||||
if (n_points_supported == 0) {
|
||||
secp256k1_scratch_destroy(&ctx->error_callback, scratch);
|
||||
continue;
|
||||
}
|
||||
bucket_window = secp256k1_pippenger_bucket_window(n_points_supported);
|
||||
CHECK(secp256k1_scratch_allocate_frame(&ctx->error_callback, scratch, secp256k1_pippenger_scratch_size(n_points_supported, bucket_window), PIPPENGER_SCRATCH_OBJECTS));
|
||||
secp256k1_scratch_deallocate_frame(&ctx->error_callback, scratch);
|
||||
/* allocate `total_alloc` bytes over `PIPPENGER_SCRATCH_OBJECTS` many allocations */
|
||||
total_alloc = secp256k1_pippenger_scratch_size(n_points_supported, bucket_window);
|
||||
for (i = 0; i < PIPPENGER_SCRATCH_OBJECTS - 1; i++) {
|
||||
CHECK(secp256k1_scratch_alloc(&ctx->error_callback, scratch, 1));
|
||||
total_alloc--;
|
||||
}
|
||||
CHECK(secp256k1_scratch_alloc(&ctx->error_callback, scratch, total_alloc));
|
||||
secp256k1_scratch_apply_checkpoint(&ctx->error_callback, scratch, checkpoint);
|
||||
secp256k1_scratch_destroy(&ctx->error_callback, scratch);
|
||||
}
|
||||
CHECK(bucket_window == PIPPENGER_MAX_BUCKET_WINDOW);
|
||||
|
|
|
|||
Loading…
Reference in New Issue