zephyr/lib/posix/options/mmap.c

129 lines
2.4 KiB
C

/*
* Copyright (c) 2024, Tenstorrent AI ULC
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <errno.h>
#include <stddef.h>
#include <sys/types.h>
#include <kernel_arch_interface.h>
#include <zephyr/kernel.h>
#include <zephyr/kernel/mm.h>
#include <zephyr/sys/fdtable.h>
#include <zephyr/posix/sys/mman.h>
#include <zephyr/posix/unistd.h>
#define _page_size COND_CODE_1(CONFIG_MMU, (CONFIG_MMU_PAGE_SIZE), (PAGE_SIZE))
int zvfs_ioctl(int fd, int cmd, va_list args);
static int p2z(int prot, int pflags)
{
bool rw = (prot & PROT_WRITE) != 0;
bool ex = (prot & PROT_EXEC) != 0;
bool fixed = (pflags & MAP_FIXED) != 0;
bool shared = (pflags & MAP_SHARED) != 0;
bool private = (pflags & MAP_PRIVATE) != 0;
if (!(shared ^ private)) {
return -1;
}
return (rw * K_MEM_PERM_RW) | (ex * K_MEM_PERM_EXEC) | (fixed * K_MEM_DIRECT_MAP);
}
static inline int zvfs_ioctl_wrap(int fd, int cmd, ...)
{
int ret;
va_list args;
va_start(args, cmd);
ret = zvfs_ioctl(fd, cmd, args);
va_end(args);
return ret;
}
void *mmap(void *addr, size_t len, int prot, int flags, int fd, off_t off)
{
void *virt;
uintptr_t phys;
int zflags = p2z(prot, flags);
if ((len == 0) || (zflags == -1)) {
errno = EINVAL;
return MAP_FAILED;
}
if ((flags & MAP_ANONYMOUS) != 0) {
/* force behaviour to be in-line with Linux, fd is ignored */
fd = -1;
}
if (fd > 0) {
/* non-anonymous mapping */
virt = NULL;
if (zvfs_ioctl_wrap(fd, ZFD_IOCTL_MMAP, addr, len, prot, flags, off, &virt) < 0) {
return MAP_FAILED;
}
return virt;
}
if (!IS_ENABLED(CONFIG_MMU)) {
errno = ENOTSUP;
return MAP_FAILED;
}
if ((flags & MAP_FIXED) == 0) {
/* anonymous mapping */
virt = k_mem_map(len, zflags);
} else {
/* a physical mapping. Care should be taken not to map the same page twice */
virt = NULL;
phys = POINTER_TO_UINT(addr);
k_mem_map_phys_bare((uint8_t **)&virt, phys, (size_t)ROUND_UP(len, _page_size),
zflags);
}
if (virt == NULL) {
errno = ENOMEM;
return MAP_FAILED;
}
return virt;
}
int msync(void *addr, size_t length, int flags)
{
ARG_UNUSED(addr);
ARG_UNUSED(length);
ARG_UNUSED(flags);
return 0;
}
int munmap(void *addr, size_t len)
{
if (len == 0) {
errno = EINVAL;
return -1;
}
if (!IS_ENABLED(CONFIG_MMU)) {
/* cannot munmap without an MPU */
errno = ENOTSUP;
return -1;
}
uintptr_t phys = 0;
if (arch_page_phys_get(addr, &phys) == 0) {
k_mem_unmap(addr, ROUND_UP(len, _page_size));
}
return 0;
}