diff options
Diffstat (limited to 'tcg/tcg.c')
| -rw-r--r-- | tcg/tcg.c | 651 |
1 files changed, 49 insertions, 602 deletions
diff --git a/tcg/tcg.c b/tcg/tcg.c index 0dc271aac9..ca482c2301 100644 --- a/tcg/tcg.c +++ b/tcg/tcg.c @@ -43,11 +43,6 @@ #define NO_CPU_IO_DEFS #include "exec/exec-all.h" - -#if !defined(CONFIG_USER_ONLY) -#include "hw/boards.h" -#endif - #include "tcg/tcg-op.h" #if UINTPTR_MAX == UINT32_MAX @@ -63,6 +58,7 @@ #include "elf.h" #include "exec/log.h" +#include "tcg-internal.h" /* Forward declarations for functions declared in tcg-target.c.inc and used here. */ @@ -153,10 +149,12 @@ static bool tcg_target_const_match(int64_t val, TCGType type, int ct); static int tcg_out_ldst_finalize(TCGContext *s); #endif -#define TCG_HIGHWATER 1024 +TCGContext tcg_init_ctx; +__thread TCGContext *tcg_ctx; -static TCGContext **tcg_ctxs; -static unsigned int n_tcg_ctxs; +TCGContext **tcg_ctxs; +unsigned int tcg_cur_ctxs; +unsigned int tcg_max_ctxs; TCGv_env cpu_env = 0; const void *tcg_code_gen_epilogue; uintptr_t tcg_splitwx_diff; @@ -165,42 +163,6 @@ uintptr_t tcg_splitwx_diff; tcg_prologue_fn *tcg_qemu_tb_exec; #endif -struct tcg_region_tree { - QemuMutex lock; - GTree *tree; - /* padding to avoid false sharing is computed at run-time */ -}; - -/* - * We divide code_gen_buffer into equally-sized "regions" that TCG threads - * dynamically allocate from as demand dictates. Given appropriate region - * sizing, this minimizes flushes even when some TCG threads generate a lot - * more code than others. - */ -struct tcg_region_state { - QemuMutex lock; - - /* fields set at init time */ - void *start; - void *start_aligned; - void *end; - size_t n; - size_t size; /* size of one region */ - size_t stride; /* .size + guard size */ - - /* fields protected by the lock */ - size_t current; /* current region index */ - size_t agg_size_full; /* aggregate size of full regions */ -}; - -static struct tcg_region_state region; -/* - * This is an array of struct tcg_region_tree's, with padding. - * We use void * to simplify the computation of region_trees[i]; each - * struct is found every tree_size bytes. - */ -static void *region_trees; -static size_t tree_size; static TCGRegSet tcg_target_available_regs[TCG_TYPE_COUNT]; static TCGRegSet tcg_target_call_clobber_regs; @@ -457,456 +419,6 @@ static const TCGTargetOpDef constraint_sets[] = { #include "tcg-target.c.inc" -/* compare a pointer @ptr and a tb_tc @s */ -static int ptr_cmp_tb_tc(const void *ptr, const struct tb_tc *s) -{ - if (ptr >= s->ptr + s->size) { - return 1; - } else if (ptr < s->ptr) { - return -1; - } - return 0; -} - -static gint tb_tc_cmp(gconstpointer ap, gconstpointer bp) -{ - const struct tb_tc *a = ap; - const struct tb_tc *b = bp; - - /* - * When both sizes are set, we know this isn't a lookup. - * This is the most likely case: every TB must be inserted; lookups - * are a lot less frequent. - */ - if (likely(a->size && b->size)) { - if (a->ptr > b->ptr) { - return 1; - } else if (a->ptr < b->ptr) { - return -1; - } - /* a->ptr == b->ptr should happen only on deletions */ - g_assert(a->size == b->size); - return 0; - } - /* - * All lookups have either .size field set to 0. - * From the glib sources we see that @ap is always the lookup key. However - * the docs provide no guarantee, so we just mark this case as likely. - */ - if (likely(a->size == 0)) { - return ptr_cmp_tb_tc(a->ptr, b); - } - return ptr_cmp_tb_tc(b->ptr, a); -} - -static void tcg_region_trees_init(void) -{ - size_t i; - - tree_size = ROUND_UP(sizeof(struct tcg_region_tree), qemu_dcache_linesize); - region_trees = qemu_memalign(qemu_dcache_linesize, region.n * tree_size); - for (i = 0; i < region.n; i++) { - struct tcg_region_tree *rt = region_trees + i * tree_size; - - qemu_mutex_init(&rt->lock); - rt->tree = g_tree_new(tb_tc_cmp); - } -} - -static struct tcg_region_tree *tc_ptr_to_region_tree(const void *p) -{ - size_t region_idx; - - /* - * Like tcg_splitwx_to_rw, with no assert. The pc may come from - * a signal handler over which the caller has no control. - */ - if (!in_code_gen_buffer(p)) { - p -= tcg_splitwx_diff; - if (!in_code_gen_buffer(p)) { - return NULL; - } - } - - if (p < region.start_aligned) { - region_idx = 0; - } else { - ptrdiff_t offset = p - region.start_aligned; - - if (offset > region.stride * (region.n - 1)) { - region_idx = region.n - 1; - } else { - region_idx = offset / region.stride; - } - } - return region_trees + region_idx * tree_size; -} - -void tcg_tb_insert(TranslationBlock *tb) -{ - struct tcg_region_tree *rt = tc_ptr_to_region_tree(tb->tc.ptr); - - g_assert(rt != NULL); - qemu_mutex_lock(&rt->lock); - g_tree_insert(rt->tree, &tb->tc, tb); - qemu_mutex_unlock(&rt->lock); -} - -void tcg_tb_remove(TranslationBlock *tb) -{ - struct tcg_region_tree *rt = tc_ptr_to_region_tree(tb->tc.ptr); - - g_assert(rt != NULL); - qemu_mutex_lock(&rt->lock); - g_tree_remove(rt->tree, &tb->tc); - qemu_mutex_unlock(&rt->lock); -} - -/* - * Find the TB 'tb' such that - * tb->tc.ptr <= tc_ptr < tb->tc.ptr + tb->tc.size - * Return NULL if not found. - */ -TranslationBlock *tcg_tb_lookup(uintptr_t tc_ptr) -{ - struct tcg_region_tree *rt = tc_ptr_to_region_tree((void *)tc_ptr); - TranslationBlock *tb; - struct tb_tc s = { .ptr = (void *)tc_ptr }; - - if (rt == NULL) { - return NULL; - } - - qemu_mutex_lock(&rt->lock); - tb = g_tree_lookup(rt->tree, &s); - qemu_mutex_unlock(&rt->lock); - return tb; -} - -static void tcg_region_tree_lock_all(void) -{ - size_t i; - - for (i = 0; i < region.n; i++) { - struct tcg_region_tree *rt = region_trees + i * tree_size; - - qemu_mutex_lock(&rt->lock); - } -} - -static void tcg_region_tree_unlock_all(void) -{ - size_t i; - - for (i = 0; i < region.n; i++) { - struct tcg_region_tree *rt = region_trees + i * tree_size; - - qemu_mutex_unlock(&rt->lock); - } -} - -void tcg_tb_foreach(GTraverseFunc func, gpointer user_data) -{ - size_t i; - - tcg_region_tree_lock_all(); - for (i = 0; i < region.n; i++) { - struct tcg_region_tree *rt = region_trees + i * tree_size; - - g_tree_foreach(rt->tree, func, user_data); - } - tcg_region_tree_unlock_all(); -} - -size_t tcg_nb_tbs(void) -{ - size_t nb_tbs = 0; - size_t i; - - tcg_region_tree_lock_all(); - for (i = 0; i < region.n; i++) { - struct tcg_region_tree *rt = region_trees + i * tree_size; - - nb_tbs += g_tree_nnodes(rt->tree); - } - tcg_region_tree_unlock_all(); - return nb_tbs; -} - -static gboolean tcg_region_tree_traverse(gpointer k, gpointer v, gpointer data) -{ - TranslationBlock *tb = v; - - tb_destroy(tb); - return FALSE; -} - -static void tcg_region_tree_reset_all(void) -{ - size_t i; - - tcg_region_tree_lock_all(); - for (i = 0; i < region.n; i++) { - struct tcg_region_tree *rt = region_trees + i * tree_size; - - g_tree_foreach(rt->tree, tcg_region_tree_traverse, NULL); - /* Increment the refcount first so that destroy acts as a reset */ - g_tree_ref(rt->tree); - g_tree_destroy(rt->tree); - } - tcg_region_tree_unlock_all(); -} - -static void tcg_region_bounds(size_t curr_region, void **pstart, void **pend) -{ - void *start, *end; - - start = region.start_aligned + curr_region * region.stride; - end = start + region.size; - - if (curr_region == 0) { - start = region.start; - } - if (curr_region == region.n - 1) { - end = region.end; - } - - *pstart = start; - *pend = end; -} - -static void tcg_region_assign(TCGContext *s, size_t curr_region) -{ - void *start, *end; - - tcg_region_bounds(curr_region, &start, &end); - - s->code_gen_buffer = start; - s->code_gen_ptr = start; - s->code_gen_buffer_size = end - start; - s->code_gen_highwater = end - TCG_HIGHWATER; -} - -static bool tcg_region_alloc__locked(TCGContext *s) -{ - if (region.current == region.n) { - return true; - } - tcg_region_assign(s, region.current); - region.current++; - return false; -} - -/* - * Request a new region once the one in use has filled up. - * Returns true on error. - */ -static bool tcg_region_alloc(TCGContext *s) -{ - bool err; - /* read the region size now; alloc__locked will overwrite it on success */ - size_t size_full = s->code_gen_buffer_size; - - qemu_mutex_lock(®ion.lock); - err = tcg_region_alloc__locked(s); - if (!err) { - region.agg_size_full += size_full - TCG_HIGHWATER; - } - qemu_mutex_unlock(®ion.lock); - return err; -} - -/* - * Perform a context's first region allocation. - * This function does _not_ increment region.agg_size_full. - */ -static inline bool tcg_region_initial_alloc__locked(TCGContext *s) -{ - return tcg_region_alloc__locked(s); -} - -/* Call from a safe-work context */ -void tcg_region_reset_all(void) -{ - unsigned int n_ctxs = qatomic_read(&n_tcg_ctxs); - unsigned int i; - - qemu_mutex_lock(®ion.lock); - region.current = 0; - region.agg_size_full = 0; - - for (i = 0; i < n_ctxs; i++) { - TCGContext *s = qatomic_read(&tcg_ctxs[i]); - bool err = tcg_region_initial_alloc__locked(s); - - g_assert(!err); - } - qemu_mutex_unlock(®ion.lock); - - tcg_region_tree_reset_all(); -} - -#ifdef CONFIG_USER_ONLY -static size_t tcg_n_regions(void) -{ - return 1; -} -#else -/* - * It is likely that some vCPUs will translate more code than others, so we - * first try to set more regions than max_cpus, with those regions being of - * reasonable size. If that's not possible we make do by evenly dividing - * the code_gen_buffer among the vCPUs. - */ -static size_t tcg_n_regions(void) -{ - size_t i; - - /* Use a single region if all we have is one vCPU thread */ -#if !defined(CONFIG_USER_ONLY) - MachineState *ms = MACHINE(qdev_get_machine()); - unsigned int max_cpus = ms->smp.max_cpus; -#endif - if (max_cpus == 1 || !qemu_tcg_mttcg_enabled()) { - return 1; - } - - /* Try to have more regions than max_cpus, with each region being >= 2 MB */ - for (i = 8; i > 0; i--) { - size_t regions_per_thread = i; - size_t region_size; - - region_size = tcg_init_ctx.code_gen_buffer_size; - region_size /= max_cpus * regions_per_thread; - - if (region_size >= 2 * 1024u * 1024) { - return max_cpus * regions_per_thread; - } - } - /* If we can't, then just allocate one region per vCPU thread */ - return max_cpus; -} -#endif - -/* - * Initializes region partitioning. - * - * Called at init time from the parent thread (i.e. the one calling - * tcg_context_init), after the target's TCG globals have been set. - * - * Region partitioning works by splitting code_gen_buffer into separate regions, - * and then assigning regions to TCG threads so that the threads can translate - * code in parallel without synchronization. - * - * In softmmu the number of TCG threads is bounded by max_cpus, so we use at - * least max_cpus regions in MTTCG. In !MTTCG we use a single region. - * Note that the TCG options from the command-line (i.e. -accel accel=tcg,[...]) - * must have been parsed before calling this function, since it calls - * qemu_tcg_mttcg_enabled(). - * - * In user-mode we use a single region. Having multiple regions in user-mode - * is not supported, because the number of vCPU threads (recall that each thread - * spawned by the guest corresponds to a vCPU thread) is only bounded by the - * OS, and usually this number is huge (tens of thousands is not uncommon). - * Thus, given this large bound on the number of vCPU threads and the fact - * that code_gen_buffer is allocated at compile-time, we cannot guarantee - * that the availability of at least one region per vCPU thread. - * - * However, this user-mode limitation is unlikely to be a significant problem - * in practice. Multi-threaded guests share most if not all of their translated - * code, which makes parallel code generation less appealing than in softmmu. - */ -void tcg_region_init(void) -{ - void *buf = tcg_init_ctx.code_gen_buffer; - void *aligned; - size_t size = tcg_init_ctx.code_gen_buffer_size; - size_t page_size = qemu_real_host_page_size; - size_t region_size; - size_t n_regions; - size_t i; - - n_regions = tcg_n_regions(); - - /* The first region will be 'aligned - buf' bytes larger than the others */ - aligned = QEMU_ALIGN_PTR_UP(buf, page_size); - g_assert(aligned < tcg_init_ctx.code_gen_buffer + size); - /* - * Make region_size a multiple of page_size, using aligned as the start. - * As a result of this we might end up with a few extra pages at the end of - * the buffer; we will assign those to the last region. - */ - region_size = (size - (aligned - buf)) / n_regions; - region_size = QEMU_ALIGN_DOWN(region_size, page_size); - - /* A region must have at least 2 pages; one code, one guard */ - g_assert(region_size >= 2 * page_size); - - /* init the region struct */ - qemu_mutex_init(®ion.lock); - region.n = n_regions; - region.size = region_size - page_size; - region.stride = region_size; - region.start = buf; - region.start_aligned = aligned; - /* page-align the end, since its last page will be a guard page */ - region.end = QEMU_ALIGN_PTR_DOWN(buf + size, page_size); - /* account for that last guard page */ - region.end -= page_size; - - /* - * Set guard pages in the rw buffer, as that's the one into which - * buffer overruns could occur. Do not set guard pages in the rx - * buffer -- let that one use hugepages throughout. - */ - for (i = 0; i < region.n; i++) { - void *start, *end; - - tcg_region_bounds(i, &start, &end); - - /* - * macOS 11.2 has a bug (Apple Feedback FB8994773) in which mprotect - * rejects a permission change from RWX -> NONE. Guard pages are - * nice for bug detection but are not essential; ignore any failure. - */ - (void)qemu_mprotect_none(end, page_size); - } - - tcg_region_trees_init(); - - /* In user-mode we support only one ctx, so do the initial allocation now */ -#ifdef CONFIG_USER_ONLY - { - bool err = tcg_region_initial_alloc__locked(tcg_ctx); - - g_assert(!err); - } -#endif -} - -#ifdef CONFIG_DEBUG_TCG -const void *tcg_splitwx_to_rx(void *rw) -{ - /* Pass NULL pointers unchanged. */ - if (rw) { - g_assert(in_code_gen_buffer(rw)); - rw += tcg_splitwx_diff; - } - return rw; -} - -void *tcg_splitwx_to_rw(const void *rx) -{ - /* Pass NULL pointers unchanged. */ - if (rx) { - rx -= tcg_splitwx_diff; - /* Assert that we end with a pointer in the rw region. */ - g_assert(in_code_gen_buffer(rx)); - } - return (void *)rx; -} -#endif /* CONFIG_DEBUG_TCG */ - static void alloc_tcg_plugin_context(TCGContext *s) { #ifdef CONFIG_PLUGIN @@ -939,10 +451,8 @@ void tcg_register_thread(void) #else void tcg_register_thread(void) { - MachineState *ms = MACHINE(qdev_get_machine()); TCGContext *s = g_malloc(sizeof(*s)); unsigned int i, n; - bool err; *s = tcg_init_ctx; @@ -956,79 +466,19 @@ void tcg_register_thread(void) } /* Claim an entry in tcg_ctxs */ - n = qatomic_fetch_inc(&n_tcg_ctxs); - g_assert(n < ms->smp.max_cpus); + n = qatomic_fetch_inc(&tcg_cur_ctxs); + g_assert(n < tcg_max_ctxs); qatomic_set(&tcg_ctxs[n], s); if (n > 0) { alloc_tcg_plugin_context(s); + tcg_region_initial_alloc(s); } tcg_ctx = s; - qemu_mutex_lock(®ion.lock); - err = tcg_region_initial_alloc__locked(tcg_ctx); - g_assert(!err); - qemu_mutex_unlock(®ion.lock); } #endif /* !CONFIG_USER_ONLY */ -/* - * Returns the size (in bytes) of all translated code (i.e. from all regions) - * currently in the cache. - * See also: tcg_code_capacity() - * Do not confuse with tcg_current_code_size(); that one applies to a single - * TCG context. - */ -size_t tcg_code_size(void) -{ - unsigned int n_ctxs = qatomic_read(&n_tcg_ctxs); - unsigned int i; - size_t total; - - qemu_mutex_lock(®ion.lock); - total = region.agg_size_full; - for (i = 0; i < n_ctxs; i++) { - const TCGContext *s = qatomic_read(&tcg_ctxs[i]); - size_t size; - - size = qatomic_read(&s->code_gen_ptr) - s->code_gen_buffer; - g_assert(size <= s->code_gen_buffer_size); - total += size; - } - qemu_mutex_unlock(®ion.lock); - return total; -} - -/* - * Returns the code capacity (in bytes) of the entire cache, i.e. including all - * regions. - * See also: tcg_code_size() - */ -size_t tcg_code_capacity(void) -{ - size_t guard_size, capacity; - - /* no need for synchronization; these variables are set at init time */ - guard_size = region.stride - region.size; - capacity = region.end + guard_size - region.start; - capacity -= region.n * (guard_size + TCG_HIGHWATER); - return capacity; -} - -size_t tcg_tb_phys_invalidate_count(void) -{ - unsigned int n_ctxs = qatomic_read(&n_tcg_ctxs); - unsigned int i; - size_t total = 0; - - for (i = 0; i < n_ctxs; i++) { - const TCGContext *s = qatomic_read(&tcg_ctxs[i]); - - total += qatomic_read(&s->tb_phys_invalidate_count); - } - return total; -} - /* pool based memory allocation */ void *tcg_malloc_internal(TCGContext *s, int size) { @@ -1101,8 +551,9 @@ static void process_op_defs(TCGContext *s); static TCGTemp *tcg_global_reg_new_internal(TCGContext *s, TCGType type, TCGReg reg, const char *name); -void tcg_context_init(TCGContext *s) +static void tcg_context_init(unsigned max_cpus) { + TCGContext *s = &tcg_init_ctx; int op, total_args, n, i; TCGOpDef *def; TCGArgConstraint *args_ct; @@ -1167,11 +618,11 @@ void tcg_context_init(TCGContext *s) */ #ifdef CONFIG_USER_ONLY tcg_ctxs = &tcg_ctx; - n_tcg_ctxs = 1; + tcg_cur_ctxs = 1; + tcg_max_ctxs = 1; #else - MachineState *ms = MACHINE(qdev_get_machine()); - unsigned int max_cpus = ms->smp.max_cpus; - tcg_ctxs = g_new(TCGContext *, max_cpus); + tcg_max_ctxs = max_cpus; + tcg_ctxs = g_new0(TCGContext *, max_cpus); #endif tcg_debug_assert(!tcg_regset_test_reg(s->reserved_regs, TCG_AREG0)); @@ -1179,6 +630,12 @@ void tcg_context_init(TCGContext *s) cpu_env = temp_tcgv_ptr(ts); } +void tcg_init(size_t tb_size, int splitwx, unsigned max_cpus) +{ + tcg_context_init(max_cpus); + tcg_region_init(tb_size, splitwx, max_cpus); +} + /* * Allocate TBs right before their corresponding translated code, making * sure that TBs and code are on different cache lines. @@ -1206,32 +663,16 @@ TranslationBlock *tcg_tb_alloc(TCGContext *s) void tcg_prologue_init(TCGContext *s) { - size_t prologue_size, total_size; - void *buf0, *buf1; - - /* Put the prologue at the beginning of code_gen_buffer. */ - buf0 = s->code_gen_buffer; - total_size = s->code_gen_buffer_size; - s->code_ptr = buf0; - s->code_buf = buf0; - s->data_gen_ptr = NULL; + size_t prologue_size; - /* - * The region trees are not yet configured, but tcg_splitwx_to_rx - * needs the bounds for an assert. - */ - region.start = buf0; - region.end = buf0 + total_size; + s->code_ptr = s->code_gen_ptr; + s->code_buf = s->code_gen_ptr; + s->data_gen_ptr = NULL; #ifndef CONFIG_TCG_INTERPRETER - tcg_qemu_tb_exec = (tcg_prologue_fn *)tcg_splitwx_to_rx(buf0); + tcg_qemu_tb_exec = (tcg_prologue_fn *)tcg_splitwx_to_rx(s->code_ptr); #endif - /* Compute a high-water mark, at which we voluntarily flush the buffer - and start over. The size here is arbitrary, significantly larger - than we expect the code generation for any one opcode to require. */ - s->code_gen_highwater = s->code_gen_buffer + (total_size - TCG_HIGHWATER); - #ifdef TCG_TARGET_NEED_POOL_LABELS s->pool_labels = NULL; #endif @@ -1248,32 +689,25 @@ void tcg_prologue_init(TCGContext *s) } #endif - buf1 = s->code_ptr; + prologue_size = tcg_current_code_size(s); + #ifndef CONFIG_TCG_INTERPRETER - flush_idcache_range((uintptr_t)tcg_splitwx_to_rx(buf0), (uintptr_t)buf0, - tcg_ptr_byte_diff(buf1, buf0)); + flush_idcache_range((uintptr_t)tcg_splitwx_to_rx(s->code_buf), + (uintptr_t)s->code_buf, prologue_size); #endif - /* Deduct the prologue from the buffer. */ - prologue_size = tcg_current_code_size(s); - s->code_gen_ptr = buf1; - s->code_gen_buffer = buf1; - s->code_buf = buf1; - total_size -= prologue_size; - s->code_gen_buffer_size = total_size; - - tcg_register_jit(tcg_splitwx_to_rx(s->code_gen_buffer), total_size); + tcg_region_prologue_set(s); #ifdef DEBUG_DISAS if (qemu_loglevel_mask(CPU_LOG_TB_OUT_ASM)) { FILE *logfile = qemu_log_lock(); qemu_log("PROLOGUE: [size=%zu]\n", prologue_size); if (s->data_gen_ptr) { - size_t code_size = s->data_gen_ptr - buf0; + size_t code_size = s->data_gen_ptr - s->code_gen_ptr; size_t data_size = prologue_size - code_size; size_t i; - log_disas(buf0, code_size); + log_disas(s->code_gen_ptr, code_size); for (i = 0; i < data_size; i += sizeof(tcg_target_ulong)) { if (sizeof(tcg_target_ulong) == 8) { @@ -1287,7 +721,7 @@ void tcg_prologue_init(TCGContext *s) } } } else { - log_disas(buf0, prologue_size); + log_disas(s->code_gen_ptr, prologue_size); } qemu_log("\n"); qemu_log_flush(); @@ -2649,6 +2083,19 @@ void tcg_op_remove(TCGContext *s, TCGOp *op) #endif } +void tcg_remove_ops_after(TCGOp *op) +{ + TCGContext *s = tcg_ctx; + + while (true) { + TCGOp *last = tcg_last_op(); + if (last == op) { + return; + } + tcg_op_remove(s, last); + } +} + static TCGOp *tcg_op_alloc(TCGOpcode opc) { TCGContext *s = tcg_ctx; @@ -4480,7 +3927,7 @@ static void tcg_reg_alloc_call(TCGContext *s, TCGOp *op) static inline void tcg_profile_snapshot(TCGProfile *prof, bool counters, bool table) { - unsigned int n_ctxs = qatomic_read(&n_tcg_ctxs); + unsigned int n_ctxs = qatomic_read(&tcg_cur_ctxs); unsigned int i; for (i = 0; i < n_ctxs; i++) { @@ -4543,7 +3990,7 @@ void tcg_dump_op_count(void) int64_t tcg_cpu_exec_time(void) { - unsigned int n_ctxs = qatomic_read(&n_tcg_ctxs); + unsigned int n_ctxs = qatomic_read(&tcg_cur_ctxs); unsigned int i; int64_t ret = 0; |