extern void ffi_closure_SYSV (void) FFI_HIDDEN;
extern void ffi_closure_SYSV_V (void) FFI_HIDDEN;
+#if FFI_EXEC_TRAMPOLINE_TABLE
+
+#include <mach/mach.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+extern void *ffi_closure_trampoline_table_page;
+
+typedef struct ffi_trampoline_table ffi_trampoline_table;
+typedef struct ffi_trampoline_table_entry ffi_trampoline_table_entry;
+
+struct ffi_trampoline_table
+{
+ /* contiguous writable and executable pages */
+ vm_address_t config_page;
+ vm_address_t trampoline_page;
+
+ /* free list tracking */
+ uint16_t free_count;
+ ffi_trampoline_table_entry *free_list;
+ ffi_trampoline_table_entry *free_list_pool;
+
+ ffi_trampoline_table *prev;
+ ffi_trampoline_table *next;
+};
+
+struct ffi_trampoline_table_entry
+{
+ void *(*trampoline) ();
+ ffi_trampoline_table_entry *next;
+};
+
+/* The trampoline configuration is placed a page prior to the trampoline's entry point */
+#define FFI_TRAMPOLINE_CODELOC_CONFIG(codeloc) ((void **) (((uint8_t *) codeloc) - PAGE_SIZE));
+
+/* Total number of trampolines that fit in one trampoline table */
+#define FFI_TRAMPOLINE_COUNT (PAGE_SIZE / FFI_TRAMPOLINE_SIZE)
+
+static pthread_mutex_t ffi_trampoline_lock = PTHREAD_MUTEX_INITIALIZER;
+static ffi_trampoline_table *ffi_trampoline_tables = NULL;
+
+static ffi_trampoline_table *
+ffi_trampoline_table_alloc ()
+{
+ ffi_trampoline_table *table = NULL;
+
+ /* Loop until we can allocate two contiguous pages */
+ while (table == NULL)
+ {
+ vm_address_t config_page = 0x0;
+ kern_return_t kt;
+
+ /* Try to allocate two pages */
+ kt =
+ vm_allocate (mach_task_self (), &config_page, PAGE_SIZE * 2,
+ VM_FLAGS_ANYWHERE);
+ if (kt != KERN_SUCCESS)
+ {
+ fprintf (stderr, "vm_allocate() failure: %d at %s:%d\n", kt,
+ __FILE__, __LINE__);
+ break;
+ }
+
+ /* Now drop the second half of the allocation to make room for the trampoline table */
+ vm_address_t trampoline_page = config_page + PAGE_SIZE;
+ kt = vm_deallocate (mach_task_self (), trampoline_page, PAGE_SIZE);
+ if (kt != KERN_SUCCESS)
+ {
+ fprintf (stderr, "vm_deallocate() failure: %d at %s:%d\n", kt,
+ __FILE__, __LINE__);
+ break;
+ }
+
+ /* Remap the trampoline table to directly follow the config page */
+ vm_prot_t cur_prot;
+ vm_prot_t max_prot;
+
+ kt =
+ vm_remap (mach_task_self (), &trampoline_page, PAGE_SIZE, 0x0, FALSE,
+ mach_task_self (),
+ (vm_address_t) & ffi_closure_trampoline_table_page, FALSE,
+ &cur_prot, &max_prot, VM_INHERIT_SHARE);
+
+ /* If we lost access to the destination trampoline page, drop our config allocation mapping and retry */
+ if (kt != KERN_SUCCESS)
+ {
+ /* Log unexpected failures */
+ if (kt != KERN_NO_SPACE)
+ {
+ fprintf (stderr, "vm_remap() failure: %d at %s:%d\n", kt,
+ __FILE__, __LINE__);
+ }
+
+ vm_deallocate (mach_task_self (), config_page, PAGE_SIZE);
+ continue;
+ }
+
+ /* We have valid trampoline and config pages */
+ table = calloc (1, sizeof (ffi_trampoline_table));
+ table->free_count = FFI_TRAMPOLINE_COUNT;
+ table->config_page = config_page;
+ table->trampoline_page = trampoline_page;
+
+ /* Create and initialize the free list */
+ table->free_list_pool =
+ calloc (FFI_TRAMPOLINE_COUNT, sizeof (ffi_trampoline_table_entry));
+
+ uint16_t i;
+ for (i = 0; i < table->free_count; i++)
+ {
+ ffi_trampoline_table_entry *entry = &table->free_list_pool[i];
+ entry->trampoline =
+ (void *) (table->trampoline_page + (i * FFI_TRAMPOLINE_SIZE));
+
+ if (i < table->free_count - 1)
+ entry->next = &table->free_list_pool[i + 1];
+ }
+
+ table->free_list = table->free_list_pool;
+ }
+
+ return table;
+}
+
+void *
+ffi_closure_alloc (size_t size, void **code)
+{
+ /* Create the closure */
+ ffi_closure *closure = malloc (size);
+ if (closure == NULL)
+ return NULL;
+
+ pthread_mutex_lock (&ffi_trampoline_lock);
+
+ /* Check for an active trampoline table with available entries. */
+ ffi_trampoline_table *table = ffi_trampoline_tables;
+ if (table == NULL || table->free_list == NULL)
+ {
+ table = ffi_trampoline_table_alloc ();
+ if (table == NULL)
+ {
+ free (closure);
+ return NULL;
+ }
+
+ /* Insert the new table at the top of the list */
+ table->next = ffi_trampoline_tables;
+ if (table->next != NULL)
+ table->next->prev = table;
+
+ ffi_trampoline_tables = table;
+ }
+
+ /* Claim the free entry */
+ ffi_trampoline_table_entry *entry = ffi_trampoline_tables->free_list;
+ ffi_trampoline_tables->free_list = entry->next;
+ ffi_trampoline_tables->free_count--;
+ entry->next = NULL;
+
+ pthread_mutex_unlock (&ffi_trampoline_lock);
+
+ /* Initialize the return values */
+ *code = entry->trampoline;
+ closure->trampoline_table = table;
+ closure->trampoline_table_entry = entry;
+
+ return closure;
+}
+
+void
+ffi_closure_free (void *ptr)
+{
+ ffi_closure *closure = ptr;
+
+ pthread_mutex_lock (&ffi_trampoline_lock);
+
+ /* Fetch the table and entry references */
+ ffi_trampoline_table *table = closure->trampoline_table;
+ ffi_trampoline_table_entry *entry = closure->trampoline_table_entry;
+
+ /* Return the entry to the free list */
+ entry->next = table->free_list;
+ table->free_list = entry;
+ table->free_count++;
+
+ /* If all trampolines within this table are free, and at least one other table exists, deallocate
+ * the table */
+ if (table->free_count == FFI_TRAMPOLINE_COUNT
+ && ffi_trampoline_tables != table)
+ {
+ /* Remove from the list */
+ if (table->prev != NULL)
+ table->prev->next = table->next;
+
+ if (table->next != NULL)
+ table->next->prev = table->prev;
+
+ /* Deallocate pages */
+ kern_return_t kt;
+ kt = vm_deallocate (mach_task_self (), table->config_page, PAGE_SIZE);
+ if (kt != KERN_SUCCESS)
+ fprintf (stderr, "vm_deallocate() failure: %d at %s:%d\n", kt,
+ __FILE__, __LINE__);
+
+ kt =
+ vm_deallocate (mach_task_self (), table->trampoline_page, PAGE_SIZE);
+ if (kt != KERN_SUCCESS)
+ fprintf (stderr, "vm_deallocate() failure: %d at %s:%d\n", kt,
+ __FILE__, __LINE__);
+
+ /* Deallocate free list */
+ free (table->free_list_pool);
+ free (table);
+ }
+ else if (ffi_trampoline_tables != table)
+ {
+ /* Otherwise, bump this table to the top of the list */
+ table->prev = NULL;
+ table->next = ffi_trampoline_tables;
+ if (ffi_trampoline_tables != NULL)
+ ffi_trampoline_tables->prev = table;
+
+ ffi_trampoline_tables = table;
+ }
+
+ pthread_mutex_unlock (&ffi_trampoline_lock);
+
+ /* Free the closure */
+ free (closure);
+}
+
+#endif
+
ffi_status
ffi_prep_closure_loc (ffi_closure *closure,
ffi_cif* cif,
void *user_data,
void *codeloc)
{
+ if (cif->abi != FFI_SYSV)
+ return FFI_BAD_ABI;
+
+ void (*start)(void);
+
+ if (cif->flags & AARCH64_FLAG_ARG_V)
+ start = ffi_closure_SYSV_V;
+ else
+ start = ffi_closure_SYSV;
+
+#if FFI_EXEC_TRAMPOLINE_TABLE
+ void **config = FFI_TRAMPOLINE_CODELOC_CONFIG (codeloc);
+ config[0] = closure;
+ config[1] = start;
+#else
static const unsigned char trampoline[16] = {
0x90, 0x00, 0x00, 0x58, /* ldr x16, tramp+16 */
0xf1, 0xff, 0xff, 0x10, /* adr x17, tramp+0 */
0x00, 0x02, 0x1f, 0xd6 /* br x16 */
};
char *tramp = closure->tramp;
- void (*start)(void);
+
+ memcpy (tramp, trampoline, sizeof(trampoline));
+
+ *(UINT64 *)(tramp + 16) = (uintptr_t)start;
- if (cif->abi != FFI_SYSV)
- return FFI_BAD_ABI;
+ ffi_clear_cache(tramp, tramp + FFI_TRAMPOLINE_SIZE);
+#endif
closure->cif = cif;
closure->fun = fun;
closure->user_data = user_data;
- memcpy (tramp, trampoline, sizeof(trampoline));
-
- if (cif->flags & AARCH64_FLAG_ARG_V)
- start = ffi_closure_SYSV_V;
- else
- start = ffi_closure_SYSV;
- *(UINT64 *)(tramp + 16) = (uintptr_t)start;
-
- ffi_clear_cache(tramp, tramp + FFI_TRAMPOLINE_SIZE);
-
return FFI_OK;
}
projects / platform / upstream / libffi.git / commitdiff