arch/tile: more /proc and /sys file support

This change introduces a few of the less controversial /proc and
/proc/sys interfaces for tile, along with sysfs attributes for
various things that were originally proposed as /proc/tile files.
It also adjusts the "hardwall" proc API.

Arnd Bergmann reviewed the initial arch/tile submission, which
included a complete set of all the /proc/tile and /proc/sys/tile
knobs that we had added in a somewhat ad hoc way during initial
development, and provided feedback on where most of them should go.

One knob turned out to be similar enough to the existing
/proc/sys/debug/exception-trace that it was re-implemented to use
that model instead.

Another knob was /proc/tile/grid, which reported the "grid" dimensions
of a tile chip (e.g. 8x8 processors = 64-core chip).  Arnd suggested
looking at sysfs for that, so this change moves that information
to a pair of sysfs attributes (chip_width and chip_height) in the
/sys/devices/system/cpu directory.  We also put the "chip_serial"
and "chip_revision" information from our old /proc/tile/board file
as attributes in /sys/devices/system/cpu.

Other information collected via hypervisor APIs is now placed in
/sys/hypervisor.  We create a /sys/hypervisor/type file (holding the
constant string "tilera") to be parallel with the Xen use of
/sys/hypervisor/type holding "xen".  We create three top-level files,
"version" (the hypervisor's own version), "config_version" (the
version of the configuration file), and "hvconfig" (the contents of
the configuration file).  The remaining information from our old
/proc/tile/board and /proc/tile/switch files becomes an attribute
group appearing under /sys/hypervisor/board/.

Finally, after some feedback from Arnd Bergmann for the previous
version of this patch, the /proc/tile/hardwall file is split up into
two conceptual parts.  First, a directory /proc/tile/hardwall/ which
contains one file per active hardwall, each file named after the
hardwall's ID and holding a cpulist that says which cpus are enclosed by
the hardwall.  Second, a /proc/PID file "hardwall" that is either
empty (for non-hardwall-using processes) or contains the hardwall ID.

Finally, this change pushes the /proc/sys/tile/unaligned_fixup/
directory, with knobs controlling the kernel code for handling the
fixup of unaligned exceptions.

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

arch/tile/Kconfig

@@ -12,6 +12,7 @@ config TILE
 	select GENERIC_IRQ_PROBE
 	select GENERIC_PENDING_IRQ if SMP
 	select GENERIC_IRQ_SHOW
+	select SYS_HYPERVISOR
 
 # FIXME: investigate whether we need/want these options.
 #	select HAVE_IOREMAP_PROT

arch/tile/include/asm/hardwall.h

@@ -40,16 +40,25 @@
 #define HARDWALL_DEACTIVATE \
  _IO(HARDWALL_IOCTL_BASE, _HARDWALL_DEACTIVATE)
 
+#define _HARDWALL_GET_ID 4
+#define HARDWALL_GET_ID \
+ _IO(HARDWALL_IOCTL_BASE, _HARDWALL_GET_ID)
+
 #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);
+/* /proc hooks for hardwall. */
+struct proc_dir_entry;
+#ifdef CONFIG_HARDWALL
+void proc_tile_hardwall_init(struct proc_dir_entry *root);
+int proc_pid_hardwall(struct task_struct *task, char *buffer);
+#else
+static inline void proc_tile_hardwall_init(struct proc_dir_entry *root) {}
+#endif
 
 #endif
 

arch/tile/kernel/Makefile

@@ -5,7 +5,7 @@
 extra-y := vmlinux.lds head_$(BITS).o
 obj-y := backtrace.o entry.o init_task.o irq.o messaging.o \
 	pci-dma.o proc.o process.o ptrace.o reboot.o \
-	setup.o signal.o single_step.o stack.o sys.o time.o traps.o \
+	setup.o signal.o single_step.o stack.o sys.o sysfs.o time.o traps.o \
 	intvec_$(BITS).o regs_$(BITS).o tile-desc_$(BITS).o
 
 obj-$(CONFIG_HARDWALL)		+= hardwall.o

arch/tile/kernel/hardwall.c

@@ -40,16 +40,25 @@
 struct hardwall_info {
 	struct list_head list;             /* "rectangles" list */
 	struct list_head task_head;        /* head of tasks in this hardwall */
+	struct cpumask cpumask;            /* cpus in the rectangle */
 	int ulhc_x;                        /* upper left hand corner x coord */
 	int ulhc_y;                        /* upper left hand corner y coord */
 	int width;                         /* rectangle width */
 	int height;                        /* rectangle height */
+	int id;                            /* integer id for this hardwall */
 	int teardown_in_progress;          /* are we tearing this one down? */
 };
 
 /* Currently allocated hardwall rectangles */
 static LIST_HEAD(rectangles);
 
+/* /proc/tile/hardwall */
+static struct proc_dir_entry *hardwall_proc_dir;
+
+/* Functions to manage files in /proc/tile/hardwall. */
+static void hardwall_add_proc(struct hardwall_info *rect);
+static void hardwall_remove_proc(struct hardwall_info *rect);
+
 /*
  * Guard changes to the hardwall data structures.
  * This could be finer grained (e.g. one lock for the list of hardwall
@@ -105,6 +114,8 @@ static int setup_rectangle(struct hardwall_info *r, struct cpumask *mask)
 	r->ulhc_y = cpu_y(ulhc);
 	r->width = cpu_x(lrhc) - r->ulhc_x + 1;
 	r->height = cpu_y(lrhc) - r->ulhc_y + 1;
+	cpumask_copy(&r->cpumask, mask);
+	r->id = ulhc;   /* The ulhc cpu id can be the hardwall id. */
 
 	/* Width and height must be positive */
 	if (r->width <= 0 || r->height <= 0)
@@ -388,6 +399,9 @@ static struct hardwall_info *hardwall_create(
 	/* Set up appropriate hardwalling on all affected cpus. */
 	hardwall_setup(rect);
 
+	/* Create a /proc/tile/hardwall entry. */
+	hardwall_add_proc(rect);
+
 	return rect;
 }
 
@@ -645,6 +659,9 @@ static void hardwall_destroy(struct hardwall_info *rect)
 	/* Restart switch and disable firewall. */
 	on_each_cpu_mask(&mask, restart_udn_switch, NULL, 1);
 
+	/* Remove the /proc/tile/hardwall entry. */
+	hardwall_remove_proc(rect);
+
 	/* Now free the rectangle from the list. */
 	spin_lock_irqsave(&hardwall_lock, flags);
 	BUG_ON(!list_empty(&rect->task_head));
@@ -654,35 +671,57 @@ static void hardwall_destroy(struct hardwall_info *rect)
 }
 
 
-/*
- * Dump hardwall state via /proc; initialized in arch/tile/sys/proc.c.
- */
-int proc_tile_hardwall_show(struct seq_file *sf, void *v)
+static int hardwall_proc_show(struct seq_file *sf, void *v)
 {
-	struct hardwall_info *r;
+	struct hardwall_info *rect = sf->private;
+	char buf[256];
 
-	if (udn_disabled) {
-		seq_printf(sf, "%dx%d 0,0 pids:\n", smp_width, smp_height);
-		return 0;
-	}
-
-	spin_lock_irq(&hardwall_lock);
-	list_for_each_entry(r, &rectangles, list) {
-		struct task_struct *p;
-		seq_printf(sf, "%dx%d %d,%d pids:",
-			   r->width, r->height, r->ulhc_x, r->ulhc_y);
-		list_for_each_entry(p, &r->task_head, thread.hardwall_list) {
-			unsigned int cpu = cpumask_first(&p->cpus_allowed);
-			unsigned int x = cpu % smp_width;
-			unsigned int y = cpu / smp_width;
-			seq_printf(sf, " %d@%d,%d", p->pid, x, y);
-		}
-		seq_printf(sf, "\n");
-	}
-	spin_unlock_irq(&hardwall_lock);
+	int rc = cpulist_scnprintf(buf, sizeof(buf), &rect->cpumask);
+	buf[rc++] = '\n';
+	seq_write(sf, buf, rc);
 	return 0;
 }
 
+static int hardwall_proc_open(struct inode *inode,
+			      struct file *file)
+{
+	return single_open(file, hardwall_proc_show, PDE(inode)->data);
+}
+
+static const struct file_operations hardwall_proc_fops = {
+	.open		= hardwall_proc_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static void hardwall_add_proc(struct hardwall_info *rect)
+{
+	char buf[64];
+	snprintf(buf, sizeof(buf), "%d", rect->id);
+	proc_create_data(buf, 0444, hardwall_proc_dir,
+			 &hardwall_proc_fops, rect);
+}
+
+static void hardwall_remove_proc(struct hardwall_info *rect)
+{
+	char buf[64];
+	snprintf(buf, sizeof(buf), "%d", rect->id);
+	remove_proc_entry(buf, hardwall_proc_dir);
+}
+
+int proc_pid_hardwall(struct task_struct *task, char *buffer)
+{
+	struct hardwall_info *rect = task->thread.hardwall;
+	return rect ? sprintf(buffer, "%d\n", rect->id) : 0;
+}
+
+void proc_tile_hardwall_init(struct proc_dir_entry *root)
+{
+	if (!udn_disabled)
+		hardwall_proc_dir = proc_mkdir("hardwall", root);
+}
+
 
 /*
  * Character device support via ioctl/close.
@@ -716,6 +755,9 @@ static long hardwall_ioctl(struct file *file, unsigned int a, unsigned long b)
 			return -EINVAL;
 		return hardwall_deactivate(current);
 
+	case _HARDWALL_GET_ID:
+		return rect ? rect->id : -EINVAL;
+
 	default:
 		return -EINVAL;
 	}

arch/tile/kernel/proc.c

@@ -27,6 +27,7 @@
 #include <asm/processor.h>
 #include <asm/sections.h>
 #include <asm/homecache.h>
+#include <asm/hardwall.h>
 #include <arch/chip.h>
 
 
@@ -88,3 +89,75 @@ const struct seq_operations cpuinfo_op = {
 	.stop	= c_stop,
 	.show	= show_cpuinfo,
 };
+
+/*
+ * Support /proc/tile directory
+ */
+
+static int __init proc_tile_init(void)
+{
+	struct proc_dir_entry *root = proc_mkdir("tile", NULL);
+	if (root == NULL)
+		return 0;
+
+	proc_tile_hardwall_init(root);
+
+	return 0;
+}
+
+arch_initcall(proc_tile_init);
+
+/*
+ * Support /proc/sys/tile directory
+ */
+
+#ifndef __tilegx__  /* FIXME: GX: no support for unaligned access yet */
+static ctl_table unaligned_subtable[] = {
+	{
+		.procname	= "enabled",
+		.data		= &unaligned_fixup,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec
+	},
+	{
+		.procname	= "printk",
+		.data		= &unaligned_printk,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec
+	},
+	{
+		.procname	= "count",
+		.data		= &unaligned_fixup_count,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec
+	},
+	{}
+};
+
+static ctl_table unaligned_table[] = {
+	{
+		.procname	= "unaligned_fixup",
+		.mode		= 0555,
+		.child		= unaligned_subtable
+	},
+	{}
+};
+#endif
+
+static struct ctl_path tile_path[] = {
+	{ .procname = "tile" },
+	{ }
+};
+
+static int __init proc_sys_tile_init(void)
+{
+#ifndef __tilegx__  /* FIXME: GX: no support for unaligned access yet */
+	register_sysctl_paths(tile_path, unaligned_table);
+#endif
+	return 0;
+}
+
+arch_initcall(proc_sys_tile_init);