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>

arch/tile/Kconfig

@@ -310,6 +310,10 @@ config VMALLOC_RESERVE
 	hex
 	default 0x1000000
 
+config HARDWALL
+	bool "Hardwall support to allow access to user dynamic network"
+	default y
+
 endmenu  # Tilera-specific configuration
 
 menu "Bus options"

arch/tile/include/asm/compat.h

@@ -222,7 +222,7 @@ struct compat_shmid64_ds {
 
 static inline void __user *compat_ptr(compat_uptr_t uptr)
 {
-	return (void __user *)(unsigned long)uptr;
+	return (void __user *)(long)(s32)uptr;
 }
 
 static inline compat_uptr_t ptr_to_compat(void __user *uptr)

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 */

arch/tile/include/asm/processor.h

@@ -21,6 +21,7 @@
  * NOTE: we don't include <linux/ptrace.h> or <linux/percpu.h> as one
  * normally would, due to #include dependencies.
  */
+#include <linux/types.h>
 #include <asm/ptrace.h>
 #include <asm/percpu.h>
 
@@ -29,7 +30,6 @@
 
 struct task_struct;
 struct thread_struct;
-struct list_head;
 
 typedef struct {
 	unsigned long seg;
@@ -74,6 +74,9 @@ struct async_tlb {
 	unsigned long address;   /* what address faulted? */
 };
 
+#ifdef CONFIG_HARDWALL
+struct hardwall_info;
+#endif
 
 struct thread_struct {
 	/* kernel stack pointer */
@@ -100,6 +103,12 @@ struct thread_struct {
 	/* Any other miscellaneous processor state bits */
 	unsigned long proc_status;
 #endif
+#ifdef CONFIG_HARDWALL
+	/* Is this task tied to an activated hardwall? */
+	struct hardwall_info *hardwall;
+	/* Chains this task into the list at hardwall->list. */
+	struct list_head hardwall_list;
+#endif
 #if CHIP_HAS_TILE_DMA()
 	/* Async DMA TLB fault information */
 	struct async_tlb dma_async_tlb;
@@ -194,8 +203,6 @@ static inline void release_thread(struct task_struct *dead_task)
 
 extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
 
-/* Helper routines for setting home cache modes at exec() time. */
-
 
 /*
  * Return saved (kernel) PC of a blocked thread.
@@ -240,6 +247,10 @@ struct siginfo;
 extern void arch_coredump_signal(struct siginfo *, struct pt_regs *);
 #define arch_coredump_signal arch_coredump_signal
 
+/* Info on this processor (see fs/proc/cpuinfo.c) */
+struct seq_operations;
+extern const struct seq_operations cpuinfo_op;
+
 /* Provide information about the chip model. */
 extern char chip_model[64];
 

arch/tile/kernel/Makefile

@@ -8,6 +8,7 @@ obj-y := backtrace.o entry.o init_task.o irq.o messaging.o \
 	setup.o signal.o single_step.o stack.o sys.o time.o traps.o \
 	intvec_$(BITS).o regs_$(BITS).o tile-desc_$(BITS).o
 
+obj-$(CONFIG_HARDWALL)		+= hardwall.o
 obj-$(CONFIG_TILEGX)		+= futex_64.o
 obj-$(CONFIG_COMPAT)		+= compat.o compat_signal.o
 obj-$(CONFIG_SMP)		+= smpboot.o smp.o tlb.o