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add a comment explaining DRM_NETBSD_ADDR2HANDLE/DRM_NETBSD_HANDLE2ADDR:

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* This hack strips the top bit from amd64 addresses, which avoid
 * udv_attach() returning NULL for "negative" offset.
 * A better hack would be to encode the offset of some kernel data
 * structure..

add a new DRM_HANDLE_NEEDS_MASK macro to check whether the above need to
be applied for various mapping types (_DRM_SHM and _DRM_SCATTER_GATHER.)
This commit is contained in:
mrg 2009-03-29 17:00:50 +00:00
parent 94f59b4d43
commit b9bbc2157f
1 changed files with 12 additions and 4 deletions
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16
sys/dev/drm/drmP.h
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@ -1,4 +1,4 @@
/* $NetBSD: drmP.h,v 1.32 2008/07/07 00:33:23 mrg Exp $ */
/* $NetBSD: drmP.h,v 1.33 2009/03/29 17:00:50 mrg Exp $ */
/* drmP.h -- Private header for Direct Rendering Manager -*- linux-c -*-
* Created: Mon Jan 4 10:05:05 1999 by faith@precisioninsight.com
@ -313,12 +313,20 @@ extern drm_device_t *drm_units[];
#define DRM_DEVICE \
drm_device_t *dev = (minor(kdev) < DRM_MAXUNITS) ? \
drm_units[minor(kdev)] : NULL
#ifdef __x86_64__
#define DRM_NETBSD_ADDR2HANDLE(addr) (addr & 0x7fffffffffffffff)
#define DRM_NETBSD_HANDLE2ADDR(handle) (handle | 0x8000000000000000)
/*
* This hack strips the top bit from amd64 addresses, which avoid
* udv_attach() returning NULL for "negative" offset.
* A better hack would be to encode the offset of some kernel data
* structure..
*/
#if defined(__x86_64__) && 1
#define DRM_NETBSD_ADDR2HANDLE(addr) ((addr) & 0x7fffffffffffffff)
#define DRM_NETBSD_HANDLE2ADDR(handle) ((handle) | 0x8000000000000000)
#define DRM_HANDLE_NEEDS_MASK(type) ((type) == _DRM_SHM || (type) == _DRM_SCATTER_GATHER)
#else
#define DRM_NETBSD_ADDR2HANDLE(addr) (addr)
#define DRM_NETBSD_HANDLE2ADDR(handle) (handle)
#define DRM_HANDLE_NEEDS_MASK(type) 0
#endif
#elif defined(__OpenBSD__)
#define DRM_DEVICE \