5 files changed, 374 insertions, 32 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index fd5c913c33c1..1205505798cc 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1888,6 +1888,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         timer: [X86] Force use of architectural NMI
                                 timer mode (see also oprofile.timer
                                 for generic hr timer mode)
+                                [s390] Force legacy basic mode sampling
+                                (report cpu_type "timer")
 
         oops=panic      Always panic on oopses. Default is to just kill the
                         process, but there is a small probability of
diff --git a/arch/s390/oprofile/hwsampler.c b/arch/s390/oprofile/hwsampler.c
index f43c0e4282af..9daee91e6c3f 100644
--- a/arch/s390/oprofile/hwsampler.c
+++ b/arch/s390/oprofile/hwsampler.c
@@ -22,6 +22,7 @@
 #include <asm/irq.h>
 
 #include "hwsampler.h"
+#include "op_counter.h"
 
 #define MAX_NUM_SDB 511
 #define MIN_NUM_SDB 1
@@ -896,6 +897,8 @@ static void add_samples_to_oprofile(unsigned int cpu, unsigned long *sdbt,
                 if (sample_data_ptr->P == 1) {
                         /* userspace sample */
                         unsigned int pid = sample_data_ptr->prim_asn;
+                        if (!counter_config.user)
+                                goto skip_sample;
                         rcu_read_lock();
                         tsk = pid_task(find_vpid(pid), PIDTYPE_PID);
                         if (tsk)
@@ -903,6 +906,8 @@ static void add_samples_to_oprofile(unsigned int cpu, unsigned long *sdbt,
                         rcu_read_unlock();
                 } else {
                         /* kernelspace sample */
+                        if (!counter_config.kernel)
+                                goto skip_sample;
                         regs = task_pt_regs(current);
                 }
 
@@ -910,7 +915,7 @@ static void add_samples_to_oprofile(unsigned int cpu, unsigned long *sdbt,
                 oprofile_add_ext_hw_sample(sample_data_ptr->ia, regs, 0,
                                 !sample_data_ptr->P, tsk);
                 mutex_unlock(&hws_sem);
-
+        skip_sample:
                 sample_data_ptr++;
         }
 }
diff --git a/arch/s390/oprofile/init.c b/arch/s390/oprofile/init.c
index 6efc18b5e60a..6cf2286d0405 100644
--- a/arch/s390/oprofile/init.c
+++ b/arch/s390/oprofile/init.c
@@ -2,10 +2,11 @@
  * arch/s390/oprofile/init.c
  *
  * S390 Version
- *   Copyright (C) 2003 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ *   Copyright (C) 2002-2011 IBM Deutschland Entwicklung GmbH, IBM Corporation
  *   Author(s): Thomas Spatzier (tspat@de.ibm.com)
  *   Author(s): Mahesh Salgaonkar (mahesh@linux.vnet.ibm.com)
  *   Author(s): Heinz Graalfs (graalfs@linux.vnet.ibm.com)
+ *   Author(s): Andreas Krebbel (krebbel@linux.vnet.ibm.com)
  *
  * @remark Copyright 2002-2011 OProfile authors
  */
@@ -14,6 +15,8 @@
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/fs.h>
+#include <linux/module.h>
+#include <asm/processor.h>
 
 #include "../../../drivers/oprofile/oprof.h"
 
@@ -22,6 +25,7 @@ extern void s390_backtrace(struct pt_regs * const regs, unsigned int depth);
 #ifdef CONFIG_64BIT
 
 #include "hwsampler.h"
+#include "op_counter.h"
 
 #define DEFAULT_INTERVAL        4127518
 
@@ -35,16 +39,41 @@ static unsigned long oprofile_max_interval;
 static unsigned long oprofile_sdbt_blocks = DEFAULT_SDBT_BLOCKS;
 static unsigned long oprofile_sdb_blocks = DEFAULT_SDB_BLOCKS;
 
-static int hwsampler_file;
+static int hwsampler_enabled;
 static int hwsampler_running;   /* start_mutex must be held to change */
+static int hwsampler_available;
 
 static struct oprofile_operations timer_ops;
 
+struct op_counter_config counter_config;
+
+enum __force_cpu_type {
+        reserved = 0,           /* do not force */
+        timer,
+};
+static int force_cpu_type;
+
+static int set_cpu_type(const char *str, struct kernel_param *kp)
+{
+        if (!strcmp(str, "timer")) {
+                force_cpu_type = timer;
+                printk(KERN_INFO "oprofile: forcing timer to be returned "
+                                 "as cpu type\n");
+        } else {
+                force_cpu_type = 0;
+        }
+
+        return 0;
+}
+module_param_call(cpu_type, set_cpu_type, NULL, NULL, 0);
+MODULE_PARM_DESC(cpu_type, "Force legacy basic mode sampling"
+                           "(report cpu_type \"timer\"");
+
 static int oprofile_hwsampler_start(void)
 {
         int retval;
 
-        hwsampler_running = hwsampler_file;
+        hwsampler_running = hwsampler_enabled;
 
         if (!hwsampler_running)
                 return timer_ops.start();
@@ -72,10 +101,16 @@ static void oprofile_hwsampler_stop(void)
         return;
 }
 
+/*
+ * File ops used for:
+ * /dev/oprofile/0/enabled
+ * /dev/oprofile/hwsampling/hwsampler  (cpu_type = timer)
+ */
+
 static ssize_t hwsampler_read(struct file *file, char __user *buf,
                 size_t count, loff_t *offset)
 {
-        return oprofilefs_ulong_to_user(hwsampler_file, buf, count, offset);
+        return oprofilefs_ulong_to_user(hwsampler_enabled, buf, count, offset);
 }
 
 static ssize_t hwsampler_write(struct file *file, char const __user *buf,
@@ -91,6 +126,9 @@ static ssize_t hwsampler_write(struct file *file, char const __user *buf,
         if (retval)
                 return retval;
 
+        if (val != 0 && val != 1)
+                return -EINVAL;
+
         if (oprofile_started)
                 /*
                  * save to do without locking as we set
@@ -99,7 +137,7 @@ static ssize_t hwsampler_write(struct file *file, char const __user *buf,
                  */
                 return -EBUSY;
 
-        hwsampler_file = val;
+        hwsampler_enabled = val;
 
         return count;
 }
@@ -109,38 +147,311 @@ static const struct file_operations hwsampler_fops = {
         .write          = hwsampler_write,
 };
 
+/*
+ * File ops used for:
+ * /dev/oprofile/0/count
+ * /dev/oprofile/hwsampling/hw_interval  (cpu_type = timer)
+ *
+ * Make sure that the value is within the hardware range.
+ */
+
+static ssize_t hw_interval_read(struct file *file, char __user *buf,
+                                size_t count, loff_t *offset)
+{
+        return oprofilefs_ulong_to_user(oprofile_hw_interval, buf,
+                                        count, offset);
+}
+
+static ssize_t hw_interval_write(struct file *file, char const __user *buf,
+                                 size_t count, loff_t *offset)
+{
+        unsigned long val;
+        int retval;
+
+        if (*offset)
+                return -EINVAL;
+        retval = oprofilefs_ulong_from_user(&val, buf, count);
+        if (retval)
+                return retval;
+        if (val < oprofile_min_interval)
+                oprofile_hw_interval = oprofile_min_interval;
+        else if (val > oprofile_max_interval)
+                oprofile_hw_interval = oprofile_max_interval;
+        else
+                oprofile_hw_interval = val;
+
+        return count;
+}
+
+static const struct file_operations hw_interval_fops = {
+        .read           = hw_interval_read,
+        .write          = hw_interval_write,
+};
+
+/*
+ * File ops used for:
+ * /dev/oprofile/0/event
+ * Only a single event with number 0 is supported with this counter.
+ *
+ * /dev/oprofile/0/unit_mask
+ * This is a dummy file needed by the user space tools.
+ * No value other than 0 is accepted or returned.
+ */
+
+static ssize_t hwsampler_zero_read(struct file *file, char __user *buf,
+                                    size_t count, loff_t *offset)
+{
+        return oprofilefs_ulong_to_user(0, buf, count, offset);
+}
+
+static ssize_t hwsampler_zero_write(struct file *file, char const __user *buf,
+                                     size_t count, loff_t *offset)
+{
+        unsigned long val;
+        int retval;
+
+        if (*offset)
+                return -EINVAL;
+
+        retval = oprofilefs_ulong_from_user(&val, buf, count);
+        if (retval)
+                return retval;
+        if (val != 0)
+                return -EINVAL;
+        return count;
+}
+
+static const struct file_operations zero_fops = {
+        .read           = hwsampler_zero_read,
+        .write          = hwsampler_zero_write,
+};
+
+/* /dev/oprofile/0/kernel file ops.  */
+
+static ssize_t hwsampler_kernel_read(struct file *file, char __user *buf,
+                                     size_t count, loff_t *offset)
+{
+        return oprofilefs_ulong_to_user(counter_config.kernel,
+                                        buf, count, offset);
+}
+
+static ssize_t hwsampler_kernel_write(struct file *file, char const __user *buf,
+                                      size_t count, loff_t *offset)
+{
+        unsigned long val;
+        int retval;
+
+        if (*offset)
+                return -EINVAL;
+
+        retval = oprofilefs_ulong_from_user(&val, buf, count);
+        if (retval)
+                return retval;
+
+        if (val != 0 && val != 1)
+                return -EINVAL;
+
+        counter_config.kernel = val;
+
+        return count;
+}
+
+static const struct file_operations kernel_fops = {
+        .read           = hwsampler_kernel_read,
+        .write          = hwsampler_kernel_write,
+};
+
+/* /dev/oprofile/0/user file ops. */
+
+static ssize_t hwsampler_user_read(struct file *file, char __user *buf,
+                                   size_t count, loff_t *offset)
+{
+        return oprofilefs_ulong_to_user(counter_config.user,
+                                        buf, count, offset);
+}
+
+static ssize_t hwsampler_user_write(struct file *file, char const __user *buf,
+                                    size_t count, loff_t *offset)
+{
+        unsigned long val;
+        int retval;
+
+        if (*offset)
+                return -EINVAL;
+
+        retval = oprofilefs_ulong_from_user(&val, buf, count);
+        if (retval)
+                return retval;
+
+        if (val != 0 && val != 1)
+                return -EINVAL;
+
+        counter_config.user = val;
+
+        return count;
+}
+
+static const struct file_operations user_fops = {
+        .read           = hwsampler_user_read,
+        .write          = hwsampler_user_write,
+};
+
+
+/*
+ * File ops used for: /dev/oprofile/timer/enabled
+ * The value always has to be the inverted value of hwsampler_enabled. So
+ * no separate variable is created. That way we do not need locking.
+ */
+
+static ssize_t timer_enabled_read(struct file *file, char __user *buf,
+                                  size_t count, loff_t *offset)
+{
+        return oprofilefs_ulong_to_user(!hwsampler_enabled, buf, count, offset);
+}
+
+static ssize_t timer_enabled_write(struct file *file, char const __user *buf,
+                                   size_t count, loff_t *offset)
+{
+        unsigned long val;
+        int retval;
+
+        if (*offset)
+                return -EINVAL;
+
+        retval = oprofilefs_ulong_from_user(&val, buf, count);
+        if (retval)
+                return retval;
+
+        if (val != 0 && val != 1)
+                return -EINVAL;
+
+        /* Timer cannot be disabled without having hardware sampling.  */
+        if (val == 0 && !hwsampler_available)
+                return -EINVAL;
+
+        if (oprofile_started)
+                /*
+                 * save to do without locking as we set
+                 * hwsampler_running in start() when start_mutex is
+                 * held
+                 */
+                return -EBUSY;
+
+        hwsampler_enabled = !val;
+
+        return count;
+}
+
+static const struct file_operations timer_enabled_fops = {
+        .read           = timer_enabled_read,
+        .write          = timer_enabled_write,
+};
+
+
 static int oprofile_create_hwsampling_files(struct super_block *sb,
-                                                struct dentry *root)
+                                            struct dentry *root)
 {
-        struct dentry *hw_dir;
+        struct dentry *dir;
+
+        dir = oprofilefs_mkdir(sb, root, "timer");
+        if (!dir)
+                return -EINVAL;
+
+        oprofilefs_create_file(sb, dir, "enabled", &timer_enabled_fops);
+
+        if (!hwsampler_available)
+                return 0;
 
         /* reinitialize default values */
-        hwsampler_file = 1;
+        hwsampler_enabled = 1;
+        counter_config.kernel = 1;
+        counter_config.user = 1;
 
-        hw_dir = oprofilefs_mkdir(sb, root, "hwsampling");
-        if (!hw_dir)
-                return -EINVAL;
+        if (!force_cpu_type) {
+                /*
+                 * Create the counter file system.  A single virtual
+                 * counter is created which can be used to
+                 * enable/disable hardware sampling dynamically from
+                 * user space.  The user space will configure a single
+                 * counter with a single event.  The value of 'event'
+                 * and 'unit_mask' are not evaluated by the kernel code
+                 * and can only be set to 0.
+                 */
+
+                dir = oprofilefs_mkdir(sb, root, "0");
+                if (!dir)
+                        return -EINVAL;
 
-        oprofilefs_create_file(sb, hw_dir, "hwsampler", &hwsampler_fops);
-        oprofilefs_create_ulong(sb, hw_dir, "hw_interval",
-                                &oprofile_hw_interval);
-        oprofilefs_create_ro_ulong(sb, hw_dir, "hw_min_interval",
-                                &oprofile_min_interval);
-        oprofilefs_create_ro_ulong(sb, hw_dir, "hw_max_interval",
-                                &oprofile_max_interval);
-        oprofilefs_create_ulong(sb, hw_dir, "hw_sdbt_blocks",
-                                &oprofile_sdbt_blocks);
+                oprofilefs_create_file(sb, dir, "enabled", &hwsampler_fops);
+                oprofilefs_create_file(sb, dir, "event", &zero_fops);
+                oprofilefs_create_file(sb, dir, "count", &hw_interval_fops);
+                oprofilefs_create_file(sb, dir, "unit_mask", &zero_fops);
+                oprofilefs_create_file(sb, dir, "kernel", &kernel_fops);
+                oprofilefs_create_file(sb, dir, "user", &user_fops);
+                oprofilefs_create_ulong(sb, dir, "hw_sdbt_blocks",
+                                        &oprofile_sdbt_blocks);
 
+        } else {
+                /*
+                 * Hardware sampling can be used but the cpu_type is
+                 * forced to timer in order to deal with legacy user
+                 * space tools.  The /dev/oprofile/hwsampling fs is
+                 * provided in that case.
+                 */
+                dir = oprofilefs_mkdir(sb, root, "hwsampling");
+                if (!dir)
+                        return -EINVAL;
+
+                oprofilefs_create_file(sb, dir, "hwsampler",
+                                       &hwsampler_fops);
+                oprofilefs_create_file(sb, dir, "hw_interval",
+                                       &hw_interval_fops);
+                oprofilefs_create_ro_ulong(sb, dir, "hw_min_interval",
+                                           &oprofile_min_interval);
+                oprofilefs_create_ro_ulong(sb, dir, "hw_max_interval",
+                                           &oprofile_max_interval);
+                oprofilefs_create_ulong(sb, dir, "hw_sdbt_blocks",
+                                        &oprofile_sdbt_blocks);
+        }
         return 0;
 }
 
 static int oprofile_hwsampler_init(struct oprofile_operations *ops)
 {
+        /*
+         * Initialize the timer mode infrastructure as well in order
+         * to be able to switch back dynamically.  oprofile_timer_init
+         * is not supposed to fail.
+         */
+        if (oprofile_timer_init(ops))
+                BUG();
+
+        memcpy(&timer_ops, ops, sizeof(timer_ops));
+        ops->create_files = oprofile_create_hwsampling_files;
+
+        /*
+         * If the user space tools do not support newer cpu types,
+         * the force_cpu_type module parameter
+         * can be used to always return \"timer\" as cpu type.
+         */
+        if (force_cpu_type != timer) {
+                struct cpuid id;
+
+                get_cpu_id (&id);
+
+                switch (id.machine) {
+                case 0x2097: case 0x2098: ops->cpu_type = "s390/z10"; break;
+                case 0x2817: case 0x2818: ops->cpu_type = "s390/z196"; break;
+                default: return -ENODEV;
+                }
+        }
+
         if (hwsampler_setup())
                 return -ENODEV;
 
         /*
-         * create hwsampler files only if hwsampler_setup() succeeds.
+         * Query the range for the sampling interval from the
+         * hardware.
          */
         oprofile_min_interval = hwsampler_query_min_interval();
         if (oprofile_min_interval == 0)
@@ -155,23 +466,17 @@ static int oprofile_hwsampler_init(struct oprofile_operations *ops)
         if (oprofile_hw_interval > oprofile_max_interval)
                 oprofile_hw_interval = oprofile_max_interval;
 
-        if (oprofile_timer_init(ops))
-                return -ENODEV;
-
-        printk(KERN_INFO "oprofile: using hardware sampling\n");
-
-        memcpy(&timer_ops, ops, sizeof(timer_ops));
+        printk(KERN_INFO "oprofile: System z hardware sampling "
+               "facility found.\n");
 
         ops->start = oprofile_hwsampler_start;
         ops->stop = oprofile_hwsampler_stop;
-        ops->create_files = oprofile_create_hwsampling_files;
 
         return 0;
 }
 
 static void oprofile_hwsampler_exit(void)
 {
-        oprofile_timer_exit();
         hwsampler_shutdown();
 }
 
@@ -182,7 +487,15 @@ int __init oprofile_arch_init(struct oprofile_operations *ops)
         ops->backtrace = s390_backtrace;
 
 #ifdef CONFIG_64BIT
-        return oprofile_hwsampler_init(ops);
+
+        /*
+         * -ENODEV is not reported to the caller.  The module itself
+         * will use the timer mode sampling as fallback and this is
+         * always available.
+         */
+        hwsampler_available = oprofile_hwsampler_init(ops) == 0;
+
+        return 0;
 #else
         return -ENODEV;
 #endif
diff --git a/arch/s390/oprofile/op_counter.h b/arch/s390/oprofile/op_counter.h
new file mode 100644
index 000000000000..1a8d3ca09014
--- /dev/null
+++ b/arch/s390/oprofile/op_counter.h
@@ -0,0 +1,23 @@
+/**
+ * arch/s390/oprofile/op_counter.h
+ *
+ *   Copyright (C) 2011 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ *   Author(s): Andreas Krebbel (krebbel@linux.vnet.ibm.com)
+ *
+ * @remark Copyright 2011 OProfile authors
+ */
+
+#ifndef OP_COUNTER_H
+#define OP_COUNTER_H
+
+struct op_counter_config {
+        /* `enabled' maps to the hwsampler_file variable.  */
+        /* `count' maps to the oprofile_hw_interval variable.  */
+        /* `event' and `unit_mask' are unused. */
+        unsigned long kernel;
+        unsigned long user;
+};
+
+extern struct op_counter_config counter_config;
+
+#endif /* OP_COUNTER_H */
diff --git a/drivers/oprofile/oprof.h b/drivers/oprofile/oprof.h
index 769fb0fcac44..d32ef816337c 100644
--- a/drivers/oprofile/oprof.h
+++ b/drivers/oprofile/oprof.h
@@ -35,7 +35,6 @@ struct dentry;
 
 void oprofile_create_files(struct super_block *sb, struct dentry *root);
 int oprofile_timer_init(struct oprofile_operations *ops);
-void oprofile_timer_exit(void);
 #ifdef CONFIG_OPROFILE_NMI_TIMER
 int op_nmi_timer_init(struct oprofile_operations *ops);
 #else