diff options
| author | Michael Brown | 2012-11-05 17:09:38 +0100 |
|---|---|---|
| committer | Michael Brown | 2012-11-05 17:15:14 +0100 |
| commit | 1494d41d0a20a1facff7558ff825a2681b419e9d (patch) | |
| tree | 63950ade91da20fa06e2b47429dea8433625f441 /src/include/ipxe/uaccess.h | |
| parent | [list] Reduce overall code size by externalising many list functions (diff) | |
| download | ipxe-1494d41d0a20a1facff7558ff825a2681b419e9d.tar.gz ipxe-1494d41d0a20a1facff7558ff825a2681b419e9d.tar.xz ipxe-1494d41d0a20a1facff7558ff825a2681b419e9d.zip | |
[uaccess] Add userptr_sub() to find the difference between two user pointers
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Diffstat (limited to 'src/include/ipxe/uaccess.h')
| -rw-r--r-- | src/include/ipxe/uaccess.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/src/include/ipxe/uaccess.h b/src/include/ipxe/uaccess.h index b574c3183..95e943675 100644 --- a/src/include/ipxe/uaccess.h +++ b/src/include/ipxe/uaccess.h @@ -83,6 +83,18 @@ trivial_userptr_add ( userptr_t userptr, off_t offset ) { } /** + * Subtract user pointers + * + * @v userptr User pointer + * @v subtrahend User pointer to be subtracted + * @ret offset Offset + */ +static inline __always_inline off_t +trivial_userptr_sub ( userptr_t userptr, userptr_t subtrahend ) { + return ( userptr - subtrahend ); +} + +/** * Copy data between user buffers * * @v dest Destination @@ -240,6 +252,15 @@ void * user_to_virt ( userptr_t userptr, off_t offset ); userptr_t userptr_add ( userptr_t userptr, off_t offset ); /** + * Subtract user pointers + * + * @v userptr User pointer + * @v subtrahend User pointer to be subtracted + * @ret offset Offset + */ +off_t userptr_sub ( userptr_t userptr, userptr_t subtrahend ); + +/** * Convert virtual address to a physical address * * @v addr Virtual address |