linux_uaccess.h

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#ifndef _IPXE_LINUX_UACCESS_H
#define _IPXE_LINUX_UACCESS_H

/** @file
 *
 * iPXE user access API for Linux
 *
 * We run with no distinction between internal and external addresses,
 * so can use trivial_virt_to_user() et al.
 *
 * We have no concept of the underlying physical addresses, since
 * these are not exposed to userspace.  We provide a stub
 * implementation of user_to_phys() since this is required by
 * alloc_memblock().  We provide no implementation of phys_to_user();
 * any code attempting to access physical addresses will therefore
 * (correctly) fail to link.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#ifdef UACCESS_LINUX
#define UACCESS_PREFIX_linux
#else
#define UACCESS_PREFIX_linux __linux_
#endif

/**
 * Convert user pointer to physical address
 *
 * @v userptr           User pointer
 * @v offset            Offset from user pointer
 * @ret phys_addr       Physical address
 */
static inline __always_inline unsigned long
UACCESS_INLINE ( linux, user_to_phys ) ( userptr_t userptr, off_t offset ) {

        /* We do not know the real underlying physical address.  We
         * provide this stub implementation only because it is
         * required by alloc_memblock() (which allocates memory with
         * specified physical address alignment).  We assume that the
         * low-order bits of virtual addresses match the low-order
         * bits of physical addresses, and so simply returning the
         * virtual address will suffice for the purpose of determining
         * alignment.
         */
        return ( userptr + offset );
}

/**
 * Convert physical address to user pointer
 *
 * @v phys_addr         Physical address
 * @ret userptr         User pointer
 */
static inline __always_inline userptr_t
UACCESS_INLINE ( linux, phys_to_user ) ( physaddr_t phys_addr ) {

        /* For symmetry with the stub user_to_phys() */
        return phys_addr;
}

static inline __always_inline userptr_t
UACCESS_INLINE ( linux, virt_to_user ) ( volatile const void *addr ) {
        return trivial_virt_to_user ( addr );
}

static inline __always_inline void *
UACCESS_INLINE ( linux, user_to_virt ) ( userptr_t userptr, off_t offset ) {
        return trivial_user_to_virt ( userptr, offset );
}

static inline __always_inline userptr_t
UACCESS_INLINE ( linux, userptr_add ) ( userptr_t userptr, off_t offset ) {
        return trivial_userptr_add ( userptr, offset );
}

static inline __always_inline off_t
UACCESS_INLINE ( linux, userptr_sub ) ( userptr_t userptr,
                                        userptr_t subtrahend ) {
        return trivial_userptr_sub ( userptr, subtrahend );
}

static inline __always_inline void
UACCESS_INLINE ( linux, memcpy_user ) ( userptr_t dest, off_t dest_off,
                                        userptr_t src, off_t src_off,
                                        size_t len ) {
        trivial_memcpy_user ( dest, dest_off, src, src_off, len );
}

static inline __always_inline void
UACCESS_INLINE ( linux, memmove_user ) ( userptr_t dest, off_t dest_off,
                                         userptr_t src, off_t src_off,
                                         size_t len ) {
        trivial_memmove_user ( dest, dest_off, src, src_off, len );
}

static inline __always_inline int
UACCESS_INLINE ( linux, memcmp_user ) ( userptr_t first, off_t first_off,
                                        userptr_t second, off_t second_off,
                                        size_t len ) {
        return trivial_memcmp_user ( first, first_off, second, second_off, len);
}

static inline __always_inline void
UACCESS_INLINE ( linux, memset_user ) ( userptr_t buffer, off_t offset,
                                        int c, size_t len ) {
        trivial_memset_user ( buffer, offset, c, len );
}

static inline __always_inline size_t
UACCESS_INLINE ( linux, strlen_user ) ( userptr_t buffer, off_t offset ) {
        return trivial_strlen_user ( buffer, offset );
}

static inline __always_inline off_t
UACCESS_INLINE ( linux, memchr_user ) ( userptr_t buffer, off_t offset,
                                        int c, size_t len ) {
        return trivial_memchr_user ( buffer, offset, c, len );
}

#endif /* _IPXE_LINUX_UACCESS_H */