[uaccess] Formalise the uaccess API

The userptr_t is now the fundamental type that gets used for conversions.
For example, virt_to_phys() is implemented in terms of virt_to_user() and
user_to_phys().

3 files changed, 333 insertions, 20 deletions

diff --git a/src/include/gpxe/io.h b/src/include/gpxe/io.h
index 24cc180f..0fc7c74e 100644
--- a/src/include/gpxe/io.h
+++ b/src/include/gpxe/io.h
@@ -19,6 +19,7 @@
 #include <stdint.h>
 #include <gpxe/api.h>
 #include <config/ioapi.h>
+#include <gpxe/uaccess.h>
 
 /**
  * Calculate static inline I/O API function name
@@ -149,24 +150,20 @@
 	} while ( 0 )
 
 /**
- * Convert virtual address to a physical address
+ * Convert physical address to a bus address
  *
- * @v addr		Virtual address
- * @ret phys_addr	Physical address
+ * @v phys_addr		Physical address
+ * @ret bus_addr	Bus address
  */
-unsigned long virt_to_phys ( volatile const void *addr );
+unsigned long phys_to_bus ( unsigned long phys_addr );
 
 /**
- * Convert physical address to a virtual address
+ * Convert bus address to a physical address
  *
- * @v addr		Virtual address
+ * @v bus_addr		Bus address
  * @ret phys_addr	Physical address
- *
- * This operation isn't actually valid within our memory model, and is
- * impossible to achieve under -DKEEP_IT_REAL.  Some drivers haven't
- * been updated to avoid it yet, though.
  */
-void * phys_to_virt ( unsigned long phys_addr );
+unsigned long bus_to_phys ( unsigned long bus_addr );
 
 /**
  * Convert virtual address to a bus address
@@ -174,7 +171,10 @@ void * phys_to_virt ( unsigned long phys_addr );
  * @v addr		Virtual address
  * @ret bus_addr	Bus address
  */
-unsigned long virt_to_bus ( volatile const void *addr );
+static inline __always_inline unsigned long
+virt_to_bus ( volatile const void *addr ) {
+	return phys_to_bus ( virt_to_phys ( addr ) );
+}
 
 /**
  * Convert bus address to a virtual address
@@ -182,11 +182,11 @@ unsigned long virt_to_bus ( volatile const void *addr );
  * @v bus_addr		Bus address
  * @ret addr		Virtual address
  *
- * This operation isn't actually valid within our memory model, and is
- * impossible to achieve under -DKEEP_IT_REAL.  Some drivers haven't
- * been updated to avoid it yet, though.
+ * This operation is not available under all memory models.
  */
-void * bus_to_virt ( unsigned long bus_addr );
+static inline __always_inline void * bus_to_virt ( unsigned long bus_addr ) {
+	return phys_to_virt ( bus_to_phys ( bus_addr ) );
+}
 
 /**
  * Map bus address as an I/O address
diff --git a/src/include/gpxe/uaccess.h b/src/include/gpxe/uaccess.h
index 05f89e03..f677b7fd 100644
--- a/src/include/gpxe/uaccess.h
+++ b/src/include/gpxe/uaccess.h
@@ -19,9 +19,323 @@
  *
  */
 
-#include <bits/uaccess.h>
+#include <stdint.h>
+#include <string.h>
+#include <gpxe/api.h>
+#include <config/ioapi.h>
+
+/**
+ * A pointer to a user buffer
+ *
+ */
+typedef unsigned long userptr_t;
 
 /** Equivalent of NULL for user pointers */
 #define UNULL ( ( userptr_t ) 0 )
 
+/**
+ * @defgroup uaccess_trivial Trivial user access API implementations
+ *
+ * User access API implementations that can be used by environments in
+ * which virtual addresses allow access to all of memory.
+ *
+ * @{
+ *
+ */
+
+/**
+ * Convert virtual address to user pointer
+ *
+ * @v addr		Virtual address
+ * @ret userptr		User pointer
+ */
+static inline __always_inline userptr_t
+trivial_virt_to_user ( volatile const void *addr ) {
+	return ( ( userptr_t ) addr );
+}
+
+/**
+ * Convert user pointer to virtual address
+ *
+ * @v userptr		User pointer
+ * @v offset		Offset from user pointer
+ * @ret addr		Virtual address
+ *
+ * This operation is not available under all memory models.
+ */
+static inline __always_inline void *
+trivial_user_to_virt ( userptr_t userptr, off_t offset ) {
+	return ( ( void * ) userptr + offset );
+}
+
+/**
+ * Add offset to user pointer
+ *
+ * @v userptr		User pointer
+ * @v offset		Offset
+ * @ret userptr		New pointer value
+ */
+static inline __always_inline userptr_t
+trivial_userptr_add ( userptr_t userptr, off_t offset ) {
+	return ( userptr + offset );
+}
+
+/**
+ * Copy data between user buffers
+ *
+ * @v dest		Destination
+ * @v dest_off		Destination offset
+ * @v src		Source
+ * @v src_off		Source offset
+ * @v len		Length
+ */
+static inline __always_inline void
+trivial_memcpy_user ( userptr_t dest, off_t dest_off,
+		      userptr_t src, off_t src_off, size_t len ) {
+	memcpy ( ( ( void * ) dest + dest_off ),
+		 ( ( void * ) src + src_off ), len );
+}
+
+/**
+ * Copy data between user buffers, allowing for overlap
+ *
+ * @v dest		Destination
+ * @v dest_off		Destination offset
+ * @v src		Source
+ * @v src_off		Source offset
+ * @v len		Length
+ */
+static inline __always_inline void
+trivial_memmove_user ( userptr_t dest, off_t dest_off,
+		       userptr_t src, off_t src_off, size_t len ) {
+	memmove ( ( ( void * ) dest + dest_off ),
+		  ( ( void * ) src + src_off ), len );
+}
+
+/**
+ * Fill user buffer with a constant byte
+ *
+ * @v buffer		User buffer
+ * @v offset		Offset within buffer
+ * @v c			Constant byte with which to fill
+ * @v len		Length
+ */
+static inline __always_inline void
+trivial_memset_user ( userptr_t buffer, off_t offset, int c, size_t len ) {
+	memset ( ( ( void * ) buffer + offset ), c, len );
+}
+
+/**
+ * Find length of NUL-terminated string in user buffer
+ *
+ * @v buffer		User buffer
+ * @v offset		Offset within buffer
+ * @ret len		Length of string (excluding NUL)
+ */
+static inline __always_inline size_t
+trivial_strlen_user ( userptr_t buffer, off_t offset ) {
+	return strlen ( ( void * ) buffer + offset );
+}
+
+/**
+ * Find character in user buffer
+ *
+ * @v buffer		User buffer
+ * @v offset		Starting offset within buffer
+ * @v c			Character to search for
+ * @v len		Length of user buffer
+ * @ret offset		Offset of character, or <0 if not found
+ */
+static inline __always_inline off_t
+trivial_memchr_user ( userptr_t buffer, off_t offset, int c, size_t len ) {
+	void *found;
+
+	found = memchr ( ( ( void * ) buffer + offset ), c, len );
+	return ( found ? ( found - ( void * ) buffer ) : -1 );
+}
+
+/** @} */
+
+/**
+ * Calculate static inline user access API function name
+ *
+ * @v _prefix		Subsystem prefix
+ * @v _api_func		API function
+ * @ret _subsys_func	Subsystem API function
+ */
+#define UACCESS_INLINE( _subsys, _api_func ) \
+	SINGLE_API_INLINE ( UACCESS_PREFIX_ ## _subsys, _api_func )
+
+/**
+ * Provide an user access API implementation
+ *
+ * @v _prefix		Subsystem prefix
+ * @v _api_func		API function
+ * @v _func		Implementing function
+ */
+#define PROVIDE_UACCESS( _subsys, _api_func, _func ) \
+	PROVIDE_SINGLE_API ( UACCESS_PREFIX_ ## _subsys, _api_func, _func )
+
+/**
+ * Provide a static inline user access API implementation
+ *
+ * @v _prefix		Subsystem prefix
+ * @v _api_func		API function
+ */
+#define PROVIDE_UACCESS_INLINE( _subsys, _api_func ) \
+	PROVIDE_SINGLE_API_INLINE ( UACCESS_PREFIX_ ## _subsys, _api_func )
+
+/* Include all architecture-independent user access API headers */
+
+/* Include all architecture-dependent user access API headers */
+#include <bits/uaccess.h>
+
+/**
+ * Convert physical address to user pointer
+ *
+ * @v phys_addr		Physical address
+ * @ret userptr		User pointer
+ */
+userptr_t phys_to_user ( unsigned long phys_addr );
+
+/**
+ * Convert user pointer to physical address
+ *
+ * @v userptr		User pointer
+ * @v offset		Offset from user pointer
+ * @ret phys_addr	Physical address
+ */
+unsigned long user_to_phys ( userptr_t userptr, off_t offset );
+
+/**
+ * Convert virtual address to user pointer
+ *
+ * @v addr		Virtual address
+ * @ret userptr		User pointer
+ */
+userptr_t virt_to_user ( volatile const void *addr );
+
+/**
+ * Convert user pointer to virtual address
+ *
+ * @v userptr		User pointer
+ * @v offset		Offset from user pointer
+ * @ret addr		Virtual address
+ *
+ * This operation is not available under all memory models.
+ */
+void * user_to_virt ( userptr_t userptr, off_t offset );
+
+/**
+ * Add offset to user pointer
+ *
+ * @v userptr		User pointer
+ * @v offset		Offset
+ * @ret userptr		New pointer value
+ */
+userptr_t userptr_add ( userptr_t userptr, off_t offset );
+
+/**
+ * Convert virtual address to a physical address
+ *
+ * @v addr		Virtual address
+ * @ret phys_addr	Physical address
+ */
+static inline __always_inline unsigned long
+virt_to_phys ( volatile const void *addr ) {
+	return user_to_phys ( virt_to_user ( addr ), 0 );
+}
+
+/**
+ * Convert physical address to a virtual address
+ *
+ * @v addr		Virtual address
+ * @ret phys_addr	Physical address
+ *
+ * This operation is not available under all memory models.
+ */
+static inline __always_inline void * phys_to_virt ( unsigned long phys_addr ) {
+	return user_to_virt ( phys_to_user ( phys_addr ), 0 );
+}
+
+/**
+ * Copy data between user buffers
+ *
+ * @v dest		Destination
+ * @v dest_off		Destination offset
+ * @v src		Source
+ * @v src_off		Source offset
+ * @v len		Length
+ */
+void memcpy_user ( userptr_t dest, off_t dest_off,
+		   userptr_t src, off_t src_off, size_t len );
+
+/**
+ * Copy data to user buffer
+ *
+ * @v dest		Destination
+ * @v dest_off		Destination offset
+ * @v src		Source
+ * @v len		Length
+ */
+static inline __always_inline void
+copy_to_user ( userptr_t dest, off_t dest_off, const void *src, size_t len ) {
+	memcpy_user ( dest, dest_off, virt_to_user ( src ), 0, len );
+}
+
+/**
+ * Copy data from user buffer
+ *
+ * @v dest		Destination
+ * @v src		Source
+ * @v src_off		Source offset
+ * @v len		Length
+ */
+static inline __always_inline void
+copy_from_user ( void *dest, userptr_t src, off_t src_off, size_t len ) {
+	memcpy_user ( virt_to_user ( dest ), 0, src, src_off, len );
+}
+
+/**
+ * Copy data between user buffers, allowing for overlap
+ *
+ * @v dest		Destination
+ * @v dest_off		Destination offset
+ * @v src		Source
+ * @v src_off		Source offset
+ * @v len		Length
+ */
+void memmove_user ( userptr_t dest, off_t dest_off,
+		    userptr_t src, off_t src_off, size_t len );
+
+/**
+ * Fill user buffer with a constant byte
+ *
+ * @v userptr		User buffer
+ * @v offset		Offset within buffer
+ * @v c			Constant byte with which to fill
+ * @v len		Length
+ */
+void memset_user ( userptr_t userptr, off_t offset, int c, size_t len );
+
+/**
+ * Find length of NUL-terminated string in user buffer
+ *
+ * @v userptr		User buffer
+ * @v offset		Offset within buffer
+ * @ret len		Length of string (excluding NUL)
+ */
+size_t strlen_user ( userptr_t userptr, off_t offset );
+
+/**
+ * Find character in user buffer
+ *
+ * @v userptr		User buffer
+ * @v offset		Starting offset within buffer
+ * @v c			Character to search for
+ * @v len		Length of user buffer
+ * @ret offset		Offset of character, or <0 if not found
+ */
+off_t memchr_user ( userptr_t userptr, off_t offset, int c, size_t len );
+
 #endif /* _GPXE_UACCESS_H */
diff --git a/src/include/pxe_types.h b/src/include/pxe_types.h
index e31af062..dd9092ef 100644
--- a/src/include/pxe_types.h
+++ b/src/include/pxe_types.h
@@ -7,9 +7,8 @@
  *
  */
 
-#include "stdint.h"
-#include "pxe_addr.h" /* Architecture-specific PXE definitions */
-#include "errno.h" /* PXE status codes */
+#include <stdint.h>
+#include <errno.h> /* PXE status codes */
 
 /** @addtogroup pxe Preboot eXecution Environment (PXE) API
  *  @{