Add interface for user-space drivers

1 files changed, 26 insertions, 0 deletions

diff --git a/microkernel/mach/gnumach/projects/mach_5.mdwn b/microkernel/mach/gnumach/projects/mach_5.mdwn
index b90f04d5..7b59170b 100644
--- a/microkernel/mach/gnumach/projects/mach_5.mdwn
+++ b/microkernel/mach/gnumach/projects/mach_5.mdwn
@@ -19,6 +19,8 @@ it, we could straighten out some of these problems.
 
 This page is a place to keep track of such changes.
 
+[[!toc startlevel=2 levels=1]]
+
 ## Protected payloads
 
 Protected payloads are a way of optimizing the receiver object lookup
@@ -135,3 +137,27 @@ A prototype exists.
 
 * <https://lists.gnu.org/archive/html/bug-hurd/2015-05/msg00000.html>
 * <https://lists.gnu.org/archive/html/bug-hurd/2016-09/msg00056.html>
+
+## Interface for userspace drivers
+
+We need to provide an interface suitable for implementing drivers in
+userspace:
+
+* A way to handle interrupts
+* and a way to allocate memory suitable for DMA buffers
+
+### Required ABI changes
+
+None.  This is a new interface.  Debian/Hurd uses a non-standard rpc
+id, so we do not change an existing procedure there.
+
+### Status
+
+A DDE-based solution is used in Debian/Hurd to provide network
+drivers.  A rump kernel prototype is implemented.  These use a kernel
+interface written by Zheng Da available in the
+"master-user_level_drivers" branch in the GNU Mach repository.
+
+### Discussions
+
+* <https://lists.gnu.org/archive/html/bug-hurd/2016-02/msg00126.html>