PR/57833 CVS commit: src/sys/external/bsd/drm2/dist/drm/i915/gem

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

The following reply was made to PR kern/57833; it has been noted by GNATS.

From: "Taylor R Campbell" <riastradh%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/57833 CVS commit: src/sys/external/bsd/drm2/dist/drm/i915/gem
Date: Fri, 19 Jan 2024 22:23:04 +0000

 Module Name:	src
 Committed By:	riastradh
 Date:		Fri Jan 19 22:23:04 UTC 2024
 
 Modified Files:
 	src/sys/external/bsd/drm2/dist/drm/i915/gem: i915_gem_phys.c
 
 Log Message:
 i915_gem_phys: Fill sg_pgs.
 
 This is needed by i915 gem fault, which maps user virtual addresses
 to those pages, and by i915 gem object destruction, which does
 pmap_page_protect on the pages to remove any of those user virtual
 mappings.
 
 This needs pmap_kenter_pa rather than pmap_enter(pmap_kernel(), ...)
 in order to preserve the _kernel's_ mapping of the pages after
 pmap_page_protect.
 
 But bus_dmamem_map currently uses pmap_enter(pmap_kernel(), ...)
 instead which creates a mapping that is removed by pmap_page_protect.
 
 So we use a variant of bus_dmamem_map that uses pmap_kenter_pa
 instead.  Perhaps bus_dmamem_map should do this itself, but this
 change is less risky to pull up than a change to bus_dmamem_map
 itself.
 
 PR kern/57833: kernel panic on xorg exit
 
 XXX pullup-10
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.8 -r1.9 \
     src/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_phys.c
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.