arch/tile: Add driver to enable access to the user dynamic network.

This network (the "UDN") connects all the cpus on the chip in a
wormhole-routed dynamic network.  Subrectangles of the chip can
be allocated by a "create" ioctl on /dev/hardwall, and then to access the
UDN in that rectangle, tasks must perform an "activate" ioctl on that
same file object after affinitizing themselves to a single cpu in
the region.  Sending a wormhole-routed message that tries to leave
that subrectangle causes all activated tasks to receive a SIGILL
(just as they would if they tried to access the UDN without first
activating themselves to a hardwall rectangle).

The original submission of this code to LKML had the driver
instantiated under /proc/tile/hardwall.  Now we just use a character
device for this, conventionally /dev/hardwall.  Some futures planning
for the TILE-Gx chip suggests that we may want to have other types of
devices that share the general model of "bind a task to a cpu, then
'activate' a file descriptor on a pseudo-device that gives access to
some hardware resource".  As such, we are using a device rather
than, for example, a syscall, to set up and activate this code.

As part of this change, the compat_ptr() declaration was fixed and used
to pass the compat_ioctl argument to the normal ioctl.  So far we limit
compat code to 2GB, so the difference between zero-extend and sign-extend
(the latter being correct, eventually) had been overlooked.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 56 insertions, 0 deletions

diff --git a/arch/tile/include/asm/hardwall.h b/arch/tile/include/asm/hardwall.h
new file mode 100644
index 000000000000..0bed3ec7b42c
--- /dev/null
+++ b/arch/tile/include/asm/hardwall.h
@@ -0,0 +1,56 @@
+/*
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful, but
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ *
+ * Provide methods for the HARDWALL_FILE for accessing the UDN.
+ */
+
+#ifndef _ASM_TILE_HARDWALL_H
+#define _ASM_TILE_HARDWALL_H
+
+#include <linux/ioctl.h>
+
+#define HARDWALL_IOCTL_BASE 0xa2
+
+/*
+ * The HARDWALL_CREATE() ioctl is a macro with a "size" argument.
+ * The resulting ioctl value is passed to the kernel in conjunction
+ * with a pointer to a little-endian bitmask of cpus, which must be
+ * physically in a rectangular configuration on the chip.
+ * The "size" is the number of bytes of cpu mask data.
+ */
+#define _HARDWALL_CREATE 1
+#define HARDWALL_CREATE(size) \
+  _IOC(_IOC_READ, HARDWALL_IOCTL_BASE, _HARDWALL_CREATE, (size))
+
+#define _HARDWALL_ACTIVATE 2
+#define HARDWALL_ACTIVATE \
+  _IO(HARDWALL_IOCTL_BASE, _HARDWALL_ACTIVATE)
+
+#define _HARDWALL_DEACTIVATE 3
+#define HARDWALL_DEACTIVATE \
+ _IO(HARDWALL_IOCTL_BASE, _HARDWALL_DEACTIVATE)
+
+#ifndef __KERNEL__
+
+/* This is the canonical name expected by userspace. */
+#define HARDWALL_FILE "/dev/hardwall"
+
+#else
+
+/* Hook for /proc/tile/hardwall. */
+struct seq_file;
+int proc_tile_hardwall_show(struct seq_file *sf, void *v);
+
+#endif
+
+#endif /* _ASM_TILE_HARDWALL_H */