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 have no concept of the underlying physical addresses, since
 * these are not exposed to userspace.  We provide a stub
 * implementation of virt_to_phys() since this is required by the heap
 * allocator to determine physical address alignment.  We provide a
 * matching stub implementation of phys_to_virt().
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
FILE_SECBOOT ( PERMITTED );

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

/**
 * Convert virtual address to physical address
 *
 * @v virt              Virtual address
 * @ret phys            Physical address
 */
static inline __always_inline physaddr_t
UACCESS_INLINE ( linux, virt_to_phys ) ( volatile const void *virt ) {

        /* We do not know the real underlying physical address.  We
         * provide this stub implementation only because it is
         * required in order to allocate memory with a 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 ( ( physaddr_t ) virt );
}

/**
 * Convert physical address to virtual address
 *
 * @v phys              Physical address
 * @ret virt            Virtual address
 */
static inline __always_inline void *
UACCESS_INLINE ( linux, phys_to_virt ) ( physaddr_t phys ) {

        /* For symmetry with the stub virt_to_phys() */
        return ( ( void * ) phys );
}

#endif /* _IPXE_LINUX_UACCESS_H */