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>

1 files changed, 185 insertions, 0 deletions

diff --git a/arch/tile/kernel/sysfs.c b/arch/tile/kernel/sysfs.c
new file mode 100644
index 000000000000..b671a86f4515
--- /dev/null
+++ b/arch/tile/kernel/sysfs.c
@@ -0,0 +1,185 @@
+/*
+ * Copyright 2011 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.
+ *
+ * /sys entry support.
+ */
+
+#include <linux/sysdev.h>
+#include <linux/cpu.h>
+#include <linux/slab.h>
+#include <linux/smp.h>
+#include <hv/hypervisor.h>
+
+/* Return a string queried from the hypervisor, truncated to page size. */
+static ssize_t get_hv_confstr(char *page, int query)
+{
+        ssize_t n = hv_confstr(query, (unsigned long)page, PAGE_SIZE - 1);
+        n = n < 0 ? 0 : min(n, (ssize_t)PAGE_SIZE - 1) - 1;
+        if (n)
+                page[n++] = '\n';
+        page[n] = '\0';
+        return n;
+}
+
+static ssize_t chip_width_show(struct sysdev_class *dev,
+                               struct sysdev_class_attribute *attr,
+                               char *page)
+{
+        return sprintf(page, "%u\n", smp_width);
+}
+static SYSDEV_CLASS_ATTR(chip_width, 0444, chip_width_show, NULL);
+
+static ssize_t chip_height_show(struct sysdev_class *dev,
+                                struct sysdev_class_attribute *attr,
+                                char *page)
+{
+        return sprintf(page, "%u\n", smp_height);
+}
+static SYSDEV_CLASS_ATTR(chip_height, 0444, chip_height_show, NULL);
+
+static ssize_t chip_serial_show(struct sysdev_class *dev,
+                                struct sysdev_class_attribute *attr,
+                                char *page)
+{
+        return get_hv_confstr(page, HV_CONFSTR_CHIP_SERIAL_NUM);
+}
+static SYSDEV_CLASS_ATTR(chip_serial, 0444, chip_serial_show, NULL);
+
+static ssize_t chip_revision_show(struct sysdev_class *dev,
+                                  struct sysdev_class_attribute *attr,
+                                  char *page)
+{
+        return get_hv_confstr(page, HV_CONFSTR_CHIP_REV);
+}
+static SYSDEV_CLASS_ATTR(chip_revision, 0444, chip_revision_show, NULL);
+
+
+static ssize_t type_show(struct sysdev_class *dev,
+                            struct sysdev_class_attribute *attr,
+                            char *page)
+{
+        return sprintf(page, "tilera\n");
+}
+static SYSDEV_CLASS_ATTR(type, 0444, type_show, NULL);
+
+#define HV_CONF_ATTR(name, conf)                                        \
+        static ssize_t name ## _show(struct sysdev_class *dev,          \
+                                     struct sysdev_class_attribute *attr, \
+                                     char *page)                        \
+        {                                                               \
+                return get_hv_confstr(page, conf);                      \
+        }                                                               \
+        static SYSDEV_CLASS_ATTR(name, 0444, name ## _show, NULL);
+
+HV_CONF_ATTR(version,           HV_CONFSTR_HV_SW_VER)
+HV_CONF_ATTR(config_version,    HV_CONFSTR_HV_CONFIG_VER)
+
+HV_CONF_ATTR(board_part,        HV_CONFSTR_BOARD_PART_NUM)
+HV_CONF_ATTR(board_serial,      HV_CONFSTR_BOARD_SERIAL_NUM)
+HV_CONF_ATTR(board_revision,    HV_CONFSTR_BOARD_REV)
+HV_CONF_ATTR(board_description, HV_CONFSTR_BOARD_DESC)
+HV_CONF_ATTR(mezz_part,         HV_CONFSTR_MEZZ_PART_NUM)
+HV_CONF_ATTR(mezz_serial,       HV_CONFSTR_MEZZ_SERIAL_NUM)
+HV_CONF_ATTR(mezz_revision,     HV_CONFSTR_MEZZ_REV)
+HV_CONF_ATTR(mezz_description,  HV_CONFSTR_MEZZ_DESC)
+HV_CONF_ATTR(switch_control,    HV_CONFSTR_SWITCH_CONTROL)
+
+static struct attribute *board_attrs[] = {
+        &attr_board_part.attr,
+        &attr_board_serial.attr,
+        &attr_board_revision.attr,
+        &attr_board_description.attr,
+        &attr_mezz_part.attr,
+        &attr_mezz_serial.attr,
+        &attr_mezz_revision.attr,
+        &attr_mezz_description.attr,
+        &attr_switch_control.attr,
+        NULL
+};
+
+static struct attribute_group board_attr_group = {
+        .name   = "board",
+        .attrs  = board_attrs,
+};
+
+
+static struct bin_attribute hvconfig_bin;
+
+static ssize_t
+hvconfig_bin_read(struct file *filp, struct kobject *kobj,
+                  struct bin_attribute *bin_attr,
+                  char *buf, loff_t off, size_t count)
+{
+        static size_t size;
+
+        /* Lazily learn the true size (minus the trailing NUL). */
+        if (size == 0)
+                size = hv_confstr(HV_CONFSTR_HV_CONFIG, 0, 0) - 1;
+
+        /* Check and adjust input parameters. */
+        if (off > size)
+                return -EINVAL;
+        if (count > size - off)
+                count = size - off;
+
+        if (count) {
+                /* Get a copy of the hvc and copy out the relevant portion. */
+                char *hvc;
+
+                size = off + count;
+                hvc = kmalloc(size, GFP_KERNEL);
+                if (hvc == NULL)
+                        return -ENOMEM;
+                hv_confstr(HV_CONFSTR_HV_CONFIG, (unsigned long)hvc, size);
+                memcpy(buf, hvc + off, count);
+                kfree(hvc);
+        }
+
+        return count;
+}
+
+static int __init create_sysfs_entries(void)
+{
+        struct sysdev_class *cls = &cpu_sysdev_class;
+        int err = 0;
+
+#define create_cpu_attr(name)                                           \
+        if (!err)                                                       \
+                err = sysfs_create_file(&cls->kset.kobj, &attr_##name.attr);
+        create_cpu_attr(chip_width);
+        create_cpu_attr(chip_height);
+        create_cpu_attr(chip_serial);
+        create_cpu_attr(chip_revision);
+
+#define create_hv_attr(name)                                            \
+        if (!err)                                                       \
+                err = sysfs_create_file(hypervisor_kobj, &attr_##name.attr);
+        create_hv_attr(type);
+        create_hv_attr(version);
+        create_hv_attr(config_version);
+
+        if (!err)
+                err = sysfs_create_group(hypervisor_kobj, &board_attr_group);
+
+        if (!err) {
+                sysfs_bin_attr_init(&hvconfig_bin);
+                hvconfig_bin.attr.name = "hvconfig";
+                hvconfig_bin.attr.mode = S_IRUGO;
+                hvconfig_bin.read = hvconfig_bin_read;
+                hvconfig_bin.size = PAGE_SIZE;
+                err = sysfs_create_bin_file(hypervisor_kobj, &hvconfig_bin);
+        }
+
+        return err;
+}
+subsys_initcall(create_sysfs_entries);