micropython/unix/alloc.c

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/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2014 Fabian Vogt
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include "py/mpstate.h"
#include "py/gc.h"
#if MICROPY_EMIT_NATIVE || (MICROPY_PY_FFI && MICROPY_FORCE_PLAT_ALLOC_EXEC)
#if defined(__OpenBSD__) || defined(__MACH__)
#define MAP_ANONYMOUS MAP_ANON
#endif
// The memory allocated here is not on the GC heap (and it may contain pointers
// that need to be GC'd) so we must somehow trace this memory. We do it by
// keeping a linked list of all mmap'd regions, and tracing them explicitly.
typedef struct _mmap_region_t {
void *ptr;
size_t len;
struct _mmap_region_t *next;
} mmap_region_t;
void mp_unix_alloc_exec(mp_uint_t min_size, void **ptr, mp_uint_t *size) {
// size needs to be a multiple of the page size
*size = (min_size + 0xfff) & (~0xfff);
*ptr = mmap(NULL, *size, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (*ptr == MAP_FAILED) {
*ptr = NULL;
}
// add new link to the list of mmap'd regions
mmap_region_t *rg = m_new_obj(mmap_region_t);
rg->ptr = *ptr;
rg->len = min_size;
rg->next = MP_STATE_VM(mmap_region_head);
MP_STATE_VM(mmap_region_head) = rg;
}
void mp_unix_free_exec(void *ptr, mp_uint_t size) {
munmap(ptr, size);
// unlink the mmap'd region from the list
for (mmap_region_t **rg = (mmap_region_t**)&MP_STATE_VM(mmap_region_head); *rg != NULL; *rg = (*rg)->next) {
if ((*rg)->ptr == ptr) {
mmap_region_t *next = (*rg)->next;
m_del_obj(mmap_region_t, *rg);
*rg = next;
return;
}
}
}
void mp_unix_mark_exec(void) {
for (mmap_region_t *rg = MP_STATE_VM(mmap_region_head); rg != NULL; rg = rg->next) {
gc_collect_root(rg->ptr, rg->len / sizeof(mp_uint_t));
}
}
#if MICROPY_FORCE_PLAT_ALLOC_EXEC
// Provide implementation of libffi ffi_closure_* functions in terms
// of the functions above. On a normal Linux system, this save a lot
// of code size.
void *ffi_closure_alloc(size_t size, void **code);
void ffi_closure_free(void *ptr);
void *ffi_closure_alloc(size_t size, void **code) {
mp_uint_t dummy;
mp_unix_alloc_exec(size, code, &dummy);
return *code;
}
void ffi_closure_free(void *ptr) {
(void)ptr;
// TODO
}
#endif
#endif // MICROPY_EMIT_NATIVE || (MICROPY_PY_FFI && MICROPY_FORCE_PLAT_ALLOC_EXEC)