* precise-event based sampling (PEBS).
*
* It manages:
- * - per-thread and per-cpu allocation of BTS and PEBS
- * - buffer memory allocation (optional)
- * - buffer overflow handling
+ * - DS and BTS hardware configuration
+ * - buffer overflow handling (to be done)
* - buffer access
*
- * It assumes:
- * - get_task_struct on all parameter tasks
- * - current is allowed to trace parameter tasks
+ * It does not do:
+ * - security checking (is the caller allowed to trace the task)
+ * - buffer allocation (memory accounting)
*
*
* Copyright (C) 2007-2008 Intel Corporation.
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/mm.h>
+#include <linux/kernel.h>
/*
* The configuration for a particular DS hardware implementation.
*/
struct ds_configuration {
- /* the size of the DS structure in bytes */
- unsigned char sizeof_ds;
- /* the size of one pointer-typed field in the DS structure in bytes;
- this covers the first 8 fields related to buffer management. */
+ /* the name of the configuration */
+ const char *name;
+ /* the size of one pointer-typed field in the DS structure and
+ in the BTS and PEBS buffers in bytes;
+ this covers the first 8 DS fields related to buffer management. */
unsigned char sizeof_field;
/* the size of a BTS/PEBS record in bytes */
unsigned char sizeof_rec[2];
+ /* a series of bit-masks to control various features indexed
+ * by enum ds_feature */
+ unsigned long ctl[dsf_ctl_max];
};
-static struct ds_configuration ds_cfg;
+static DEFINE_PER_CPU(struct ds_configuration, ds_cfg_array);
+#define ds_cfg per_cpu(ds_cfg_array, smp_processor_id())
+
+#define MAX_SIZEOF_DS (12 * 8) /* maximal size of a DS configuration */
+#define MAX_SIZEOF_BTS (3 * 8) /* maximal size of a BTS record */
+#define DS_ALIGNMENT (1 << 3) /* BTS and PEBS buffer alignment */
+
+#define BTS_CONTROL \
+ (ds_cfg.ctl[dsf_bts] | ds_cfg.ctl[dsf_bts_kernel] | ds_cfg.ctl[dsf_bts_user] |\
+ ds_cfg.ctl[dsf_bts_overflow])
+
+
+/*
+ * A BTS or PEBS tracer.
+ *
+ * This holds the configuration of the tracer and serves as a handle
+ * to identify tracers.
+ */
+struct ds_tracer {
+ /* the DS context (partially) owned by this tracer */
+ struct ds_context *context;
+ /* the buffer provided on ds_request() and its size in bytes */
+ void *buffer;
+ size_t size;
+};
+
+struct bts_tracer {
+ /* the common DS part */
+ struct ds_tracer ds;
+ /* the trace including the DS configuration */
+ struct bts_trace trace;
+ /* buffer overflow notification function */
+ bts_ovfl_callback_t ovfl;
+};
+
+struct pebs_tracer {
+ /* the common DS part */
+ struct ds_tracer ds;
+ /* the trace including the DS configuration */
+ struct pebs_trace trace;
+ /* buffer overflow notification function */
+ pebs_ovfl_callback_t ovfl;
+};
/*
* Debug Store (DS) save area configuration (see Intel64 and IA32
/*
- * Locking is done only for allocating BTS or PEBS resources and for
- * guarding context and buffer memory allocation.
- *
- * Most functions require the current task to own the ds context part
- * they are going to access. All the locking is done when validating
- * access to the context.
+ * Locking is done only for allocating BTS or PEBS resources.
*/
-static spinlock_t ds_lock = __SPIN_LOCK_UNLOCKED(ds_lock);
-
-/*
- * Validate that the current task is allowed to access the BTS/PEBS
- * buffer of the parameter task.
- *
- * Returns 0, if access is granted; -Eerrno, otherwise.
- */
-static inline int ds_validate_access(struct ds_context *context,
- enum ds_qualifier qual)
-{
- if (!context)
- return -EPERM;
-
- if (context->owner[qual] == current)
- return 0;
-
- return -EPERM;
-}
+static DEFINE_SPINLOCK(ds_lock);
/*
* >0 number of per-thread tracers
* <0 number of per-cpu tracers
*
- * The below functions to get and put tracers and to check the
- * allocation type require the ds_lock to be held by the caller.
- *
* Tracers essentially gives the number of ds contexts for a certain
* type of allocation.
*/
-static long tracers;
+static atomic_t tracers = ATOMIC_INIT(0);
static inline void get_tracer(struct task_struct *task)
{
- tracers += (task ? 1 : -1);
+ if (task)
+ atomic_inc(&tracers);
+ else
+ atomic_dec(&tracers);
}
static inline void put_tracer(struct task_struct *task)
{
- tracers -= (task ? 1 : -1);
+ if (task)
+ atomic_dec(&tracers);
+ else
+ atomic_inc(&tracers);
}
static inline int check_tracer(struct task_struct *task)
{
- return (task ? (tracers >= 0) : (tracers <= 0));
+ return task ?
+ (atomic_read(&tracers) >= 0) :
+ (atomic_read(&tracers) <= 0);
}
*
* Contexts are use-counted. They are allocated on first access and
* deallocated when the last user puts the context.
- *
- * We distinguish between an allocating and a non-allocating get of a
- * context:
- * - the allocating get is used for requesting BTS/PEBS resources. It
- * requires the caller to hold the global ds_lock.
- * - the non-allocating get is used for all other cases. A
- * non-existing context indicates an error. It acquires and releases
- * the ds_lock itself for obtaining the context.
- *
- * A context and its DS configuration are allocated and deallocated
- * together. A context always has a DS configuration of the
- * appropriate size.
- */
-static DEFINE_PER_CPU(struct ds_context *, system_context);
-
-#define this_system_context per_cpu(system_context, smp_processor_id())
-
-/*
- * Returns the pointer to the parameter task's context or to the
- * system-wide context, if task is NULL.
- *
- * Increases the use count of the returned context, if not NULL.
*/
-static inline struct ds_context *ds_get_context(struct task_struct *task)
-{
- struct ds_context *context;
- unsigned long irq;
+struct ds_context {
+ /* pointer to the DS configuration; goes into MSR_IA32_DS_AREA */
+ unsigned char ds[MAX_SIZEOF_DS];
+ /* the owner of the BTS and PEBS configuration, respectively */
+ struct bts_tracer *bts_master;
+ struct pebs_tracer *pebs_master;
+ /* use count */
+ unsigned long count;
+ /* a pointer to the context location inside the thread_struct
+ * or the per_cpu context array */
+ struct ds_context **this;
+ /* a pointer to the task owning this context, or NULL, if the
+ * context is owned by a cpu */
+ struct task_struct *task;
+};
- spin_lock_irqsave(&ds_lock, irq);
+static DEFINE_PER_CPU(struct ds_context *, system_context_array);
- context = (task ? task->thread.ds_ctx : this_system_context);
- if (context)
- context->count++;
+#define system_context per_cpu(system_context_array, smp_processor_id())
- spin_unlock_irqrestore(&ds_lock, irq);
-
- return context;
-}
-/*
- * Same as ds_get_context, but allocates the context and it's DS
- * structure, if necessary; returns NULL; if out of memory.
- */
-static inline struct ds_context *ds_alloc_context(struct task_struct *task)
+static inline struct ds_context *ds_get_context(struct task_struct *task)
{
struct ds_context **p_context =
- (task ? &task->thread.ds_ctx : &this_system_context);
- struct ds_context *context = *p_context;
+ (task ? &task->thread.ds_ctx : &system_context);
+ struct ds_context *context = NULL;
+ struct ds_context *new_context = NULL;
unsigned long irq;
- if (!context) {
- context = kzalloc(sizeof(*context), GFP_KERNEL);
- if (!context)
- return NULL;
-
- context->ds = kzalloc(ds_cfg.sizeof_ds, GFP_KERNEL);
- if (!context->ds) {
- kfree(context);
- return NULL;
- }
+ /* Chances are small that we already have a context. */
+ new_context = kzalloc(sizeof(*new_context), GFP_KERNEL);
+ if (!new_context)
+ return NULL;
- spin_lock_irqsave(&ds_lock, irq);
+ spin_lock_irqsave(&ds_lock, irq);
- if (*p_context) {
- kfree(context->ds);
- kfree(context);
+ context = *p_context;
+ if (!context) {
+ context = new_context;
- context = *p_context;
- } else {
- *p_context = context;
+ context->this = p_context;
+ context->task = task;
+ context->count = 0;
- context->this = p_context;
- context->task = task;
+ if (task)
+ set_tsk_thread_flag(task, TIF_DS_AREA_MSR);
- if (task)
- set_tsk_thread_flag(task, TIF_DS_AREA_MSR);
+ if (!task || (task == current))
+ wrmsrl(MSR_IA32_DS_AREA, (unsigned long)context->ds);
- if (!task || (task == current))
- wrmsrl(MSR_IA32_DS_AREA,
- (unsigned long)context->ds);
- }
- spin_unlock_irqrestore(&ds_lock, irq);
+ *p_context = context;
}
context->count++;
+ spin_unlock_irqrestore(&ds_lock, irq);
+
+ if (context != new_context)
+ kfree(new_context);
+
return context;
}
-/*
- * Decreases the use count of the parameter context, if not NULL.
- * Deallocates the context, if the use count reaches zero.
- */
static inline void ds_put_context(struct ds_context *context)
{
unsigned long irq;
spin_lock_irqsave(&ds_lock, irq);
- if (--context->count)
- goto out;
+ if (--context->count) {
+ spin_unlock_irqrestore(&ds_lock, irq);
+ return;
+ }
*(context->this) = NULL;
if (!context->task || (context->task == current))
wrmsrl(MSR_IA32_DS_AREA, 0);
- put_tracer(context->task);
+ spin_unlock_irqrestore(&ds_lock, irq);
- /* free any leftover buffers from tracers that did not
- * deallocate them properly. */
- kfree(context->buffer[ds_bts]);
- kfree(context->buffer[ds_pebs]);
- kfree(context->ds);
kfree(context);
- out:
- spin_unlock_irqrestore(&ds_lock, irq);
}
/*
- * Handle a buffer overflow
+ * Call the tracer's callback on a buffer overflow.
*
- * task: the task whose buffers are overflowing;
- * NULL for a buffer overflow on the current cpu
* context: the ds context
* qual: the buffer type
*/
-static void ds_overflow(struct task_struct *task, struct ds_context *context,
- enum ds_qualifier qual)
+static void ds_overflow(struct ds_context *context, enum ds_qualifier qual)
{
- if (!context)
- return;
-
- if (context->callback[qual])
- (*context->callback[qual])(task);
-
- /* todo: do some more overflow handling */
+ switch (qual) {
+ case ds_bts:
+ if (context->bts_master &&
+ context->bts_master->ovfl)
+ context->bts_master->ovfl(context->bts_master);
+ break;
+ case ds_pebs:
+ if (context->pebs_master &&
+ context->pebs_master->ovfl)
+ context->pebs_master->ovfl(context->pebs_master);
+ break;
+ }
}
/*
- * Allocate a non-pageable buffer of the parameter size.
- * Checks the memory and the locked memory rlimit.
+ * Write raw data into the BTS or PEBS buffer.
*
- * Returns the buffer, if successful;
- * NULL, if out of memory or rlimit exceeded.
+ * The remainder of any partially written record is zeroed out.
*
- * size: the requested buffer size in bytes
- * pages (out): if not NULL, contains the number of pages reserved
+ * context: the DS context
+ * qual: the buffer type
+ * record: the data to write
+ * size: the size of the data
*/
-static inline void *ds_allocate_buffer(size_t size, unsigned int *pages)
+static int ds_write(struct ds_context *context, enum ds_qualifier qual,
+ const void *record, size_t size)
{
- unsigned long rlim, vm, pgsz;
- void *buffer;
+ int bytes_written = 0;
- pgsz = PAGE_ALIGN(size) >> PAGE_SHIFT;
+ if (!record)
+ return -EINVAL;
- rlim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
- vm = current->mm->total_vm + pgsz;
- if (rlim < vm)
- return NULL;
+ while (size) {
+ unsigned long base, index, end, write_end, int_th;
+ unsigned long write_size, adj_write_size;
- rlim = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
- vm = current->mm->locked_vm + pgsz;
- if (rlim < vm)
- return NULL;
+ /*
+ * write as much as possible without producing an
+ * overflow interrupt.
+ *
+ * interrupt_threshold must either be
+ * - bigger than absolute_maximum or
+ * - point to a record between buffer_base and absolute_maximum
+ *
+ * index points to a valid record.
+ */
+ base = ds_get(context->ds, qual, ds_buffer_base);
+ index = ds_get(context->ds, qual, ds_index);
+ end = ds_get(context->ds, qual, ds_absolute_maximum);
+ int_th = ds_get(context->ds, qual, ds_interrupt_threshold);
- buffer = kzalloc(size, GFP_KERNEL);
- if (!buffer)
- return NULL;
+ write_end = min(end, int_th);
- current->mm->total_vm += pgsz;
- current->mm->locked_vm += pgsz;
+ /* if we are already beyond the interrupt threshold,
+ * we fill the entire buffer */
+ if (write_end <= index)
+ write_end = end;
- if (pages)
- *pages = pgsz;
+ if (write_end <= index)
+ break;
+
+ write_size = min((unsigned long) size, write_end - index);
+ memcpy((void *)index, record, write_size);
- return buffer;
+ record = (const char *)record + write_size;
+ size -= write_size;
+ bytes_written += write_size;
+
+ adj_write_size = write_size / ds_cfg.sizeof_rec[qual];
+ adj_write_size *= ds_cfg.sizeof_rec[qual];
+
+ /* zero out trailing bytes */
+ memset((char *)index + write_size, 0,
+ adj_write_size - write_size);
+ index += adj_write_size;
+
+ if (index >= end)
+ index = base;
+ ds_set(context->ds, qual, ds_index, index);
+
+ if (index >= int_th)
+ ds_overflow(context, qual);
+ }
+
+ return bytes_written;
}
-static int ds_request(struct task_struct *task, void *base, size_t size,
- ds_ovfl_callback_t ovfl, enum ds_qualifier qual)
+
+/*
+ * Branch Trace Store (BTS) uses the following format. Different
+ * architectures vary in the size of those fields.
+ * - source linear address
+ * - destination linear address
+ * - flags
+ *
+ * Later architectures use 64bit pointers throughout, whereas earlier
+ * architectures use 32bit pointers in 32bit mode.
+ *
+ * We compute the base address for the first 8 fields based on:
+ * - the field size stored in the DS configuration
+ * - the relative field position
+ *
+ * In order to store additional information in the BTS buffer, we use
+ * a special source address to indicate that the record requires
+ * special interpretation.
+ *
+ * Netburst indicated via a bit in the flags field whether the branch
+ * was predicted; this is ignored.
+ *
+ * We use two levels of abstraction:
+ * - the raw data level defined here
+ * - an arch-independent level defined in ds.h
+ */
+
+enum bts_field {
+ bts_from,
+ bts_to,
+ bts_flags,
+
+ bts_qual = bts_from,
+ bts_jiffies = bts_to,
+ bts_pid = bts_flags,
+
+ bts_qual_mask = (bts_qual_max - 1),
+ bts_escape = ((unsigned long)-1 & ~bts_qual_mask)
+};
+
+static inline unsigned long bts_get(const char *base, enum bts_field field)
{
- struct ds_context *context;
- unsigned long buffer, adj;
- const unsigned long alignment = (1 << 3);
- unsigned long irq;
- int error = 0;
+ base += (ds_cfg.sizeof_field * field);
+ return *(unsigned long *)base;
+}
+
+static inline void bts_set(char *base, enum bts_field field, unsigned long val)
+{
+ base += (ds_cfg.sizeof_field * field);;
+ (*(unsigned long *)base) = val;
+}
- if (!ds_cfg.sizeof_ds)
- return -EOPNOTSUPP;
- /* we require some space to do alignment adjustments below */
- if (size < (alignment + ds_cfg.sizeof_rec[qual]))
+/*
+ * The raw BTS data is architecture dependent.
+ *
+ * For higher-level users, we give an arch-independent view.
+ * - ds.h defines struct bts_struct
+ * - bts_read translates one raw bts record into a bts_struct
+ * - bts_write translates one bts_struct into the raw format and
+ * writes it into the top of the parameter tracer's buffer.
+ *
+ * return: bytes read/written on success; -Eerrno, otherwise
+ */
+static int bts_read(struct bts_tracer *tracer, const void *at,
+ struct bts_struct *out)
+{
+ if (!tracer)
return -EINVAL;
- /* buffer overflow notification is not yet implemented */
- if (ovfl)
- return -EOPNOTSUPP;
+ if (at < tracer->trace.ds.begin)
+ return -EINVAL;
+ if (tracer->trace.ds.end < (at + tracer->trace.ds.size))
+ return -EINVAL;
- context = ds_alloc_context(task);
- if (!context)
- return -ENOMEM;
+ memset(out, 0, sizeof(*out));
+ if ((bts_get(at, bts_qual) & ~bts_qual_mask) == bts_escape) {
+ out->qualifier = (bts_get(at, bts_qual) & bts_qual_mask);
+ out->variant.timestamp.jiffies = bts_get(at, bts_jiffies);
+ out->variant.timestamp.pid = bts_get(at, bts_pid);
+ } else {
+ out->qualifier = bts_branch;
+ out->variant.lbr.from = bts_get(at, bts_from);
+ out->variant.lbr.to = bts_get(at, bts_to);
+
+ if (!out->variant.lbr.from && !out->variant.lbr.to)
+ out->qualifier = bts_invalid;
+ }
- spin_lock_irqsave(&ds_lock, irq);
+ return ds_cfg.sizeof_rec[ds_bts];
+}
- error = -EPERM;
- if (!check_tracer(task))
- goto out_unlock;
+static int bts_write(struct bts_tracer *tracer, const struct bts_struct *in)
+{
+ unsigned char raw[MAX_SIZEOF_BTS];
- get_tracer(task);
+ if (!tracer)
+ return -EINVAL;
- error = -EALREADY;
- if (context->owner[qual] == current)
- goto out_put_tracer;
- error = -EPERM;
- if (context->owner[qual] != NULL)
- goto out_put_tracer;
- context->owner[qual] = current;
+ if (MAX_SIZEOF_BTS < ds_cfg.sizeof_rec[ds_bts])
+ return -EOVERFLOW;
- spin_unlock_irqrestore(&ds_lock, irq);
+ switch (in->qualifier) {
+ case bts_invalid:
+ bts_set(raw, bts_from, 0);
+ bts_set(raw, bts_to, 0);
+ bts_set(raw, bts_flags, 0);
+ break;
+ case bts_branch:
+ bts_set(raw, bts_from, in->variant.lbr.from);
+ bts_set(raw, bts_to, in->variant.lbr.to);
+ bts_set(raw, bts_flags, 0);
+ break;
+ case bts_task_arrives:
+ case bts_task_departs:
+ bts_set(raw, bts_qual, (bts_escape | in->qualifier));
+ bts_set(raw, bts_jiffies, in->variant.timestamp.jiffies);
+ bts_set(raw, bts_pid, in->variant.timestamp.pid);
+ break;
+ default:
+ return -EINVAL;
+ }
+ return ds_write(tracer->ds.context, ds_bts, raw,
+ ds_cfg.sizeof_rec[ds_bts]);
+}
- error = -ENOMEM;
- if (!base) {
- base = ds_allocate_buffer(size, &context->pages[qual]);
- if (!base)
- goto out_release;
- context->buffer[qual] = base;
- }
- error = 0;
+static void ds_write_config(struct ds_context *context,
+ struct ds_trace *cfg, enum ds_qualifier qual)
+{
+ unsigned char *ds = context->ds;
+
+ ds_set(ds, qual, ds_buffer_base, (unsigned long)cfg->begin);
+ ds_set(ds, qual, ds_index, (unsigned long)cfg->top);
+ ds_set(ds, qual, ds_absolute_maximum, (unsigned long)cfg->end);
+ ds_set(ds, qual, ds_interrupt_threshold, (unsigned long)cfg->ith);
+}
+
+static void ds_read_config(struct ds_context *context,
+ struct ds_trace *cfg, enum ds_qualifier qual)
+{
+ unsigned char *ds = context->ds;
- context->callback[qual] = ovfl;
+ cfg->begin = (void *)ds_get(ds, qual, ds_buffer_base);
+ cfg->top = (void *)ds_get(ds, qual, ds_index);
+ cfg->end = (void *)ds_get(ds, qual, ds_absolute_maximum);
+ cfg->ith = (void *)ds_get(ds, qual, ds_interrupt_threshold);
+}
+
+static void ds_init_ds_trace(struct ds_trace *trace, enum ds_qualifier qual,
+ void *base, size_t size, size_t ith,
+ unsigned int flags) {
+ unsigned long buffer, adj;
/* adjust the buffer address and size to meet alignment
* constraints:
*/
buffer = (unsigned long)base;
- adj = ALIGN(buffer, alignment) - buffer;
+ adj = ALIGN(buffer, DS_ALIGNMENT) - buffer;
buffer += adj;
size -= adj;
- size /= ds_cfg.sizeof_rec[qual];
- size *= ds_cfg.sizeof_rec[qual];
-
- ds_set(context->ds, qual, ds_buffer_base, buffer);
- ds_set(context->ds, qual, ds_index, buffer);
- ds_set(context->ds, qual, ds_absolute_maximum, buffer + size);
+ trace->n = size / ds_cfg.sizeof_rec[qual];
+ trace->size = ds_cfg.sizeof_rec[qual];
- if (ovfl) {
- /* todo: select a suitable interrupt threshold */
- } else
- ds_set(context->ds, qual,
- ds_interrupt_threshold, buffer + size + 1);
+ size = (trace->n * trace->size);
- /* we keep the context until ds_release */
- return error;
-
- out_release:
- context->owner[qual] = NULL;
- ds_put_context(context);
- put_tracer(task);
- return error;
-
- out_put_tracer:
- spin_unlock_irqrestore(&ds_lock, irq);
- ds_put_context(context);
- put_tracer(task);
- return error;
+ trace->begin = (void *)buffer;
+ trace->top = trace->begin;
+ trace->end = (void *)(buffer + size);
+ /* The value for 'no threshold' is -1, which will set the
+ * threshold outside of the buffer, just like we want it.
+ */
+ trace->ith = (void *)(buffer + size - ith);
- out_unlock:
- spin_unlock_irqrestore(&ds_lock, irq);
- ds_put_context(context);
- return error;
+ trace->flags = flags;
}
-int ds_request_bts(struct task_struct *task, void *base, size_t size,
- ds_ovfl_callback_t ovfl)
-{
- return ds_request(task, base, size, ovfl, ds_bts);
-}
-int ds_request_pebs(struct task_struct *task, void *base, size_t size,
- ds_ovfl_callback_t ovfl)
-{
- return ds_request(task, base, size, ovfl, ds_pebs);
-}
-
-static int ds_release(struct task_struct *task, enum ds_qualifier qual)
+static int ds_request(struct ds_tracer *tracer, struct ds_trace *trace,
+ enum ds_qualifier qual, struct task_struct *task,
+ void *base, size_t size, size_t th, unsigned int flags)
{
struct ds_context *context;
int error;
- context = ds_get_context(task);
- error = ds_validate_access(context, qual);
- if (error < 0)
+ error = -EINVAL;
+ if (!base)
goto out;
- kfree(context->buffer[qual]);
- context->buffer[qual] = NULL;
-
- current->mm->total_vm -= context->pages[qual];
- current->mm->locked_vm -= context->pages[qual];
- context->pages[qual] = 0;
- context->owner[qual] = NULL;
-
- /*
- * we put the context twice:
- * once for the ds_get_context
- * once for the corresponding ds_request
- */
- ds_put_context(context);
- out:
- ds_put_context(context);
- return error;
-}
+ /* we require some space to do alignment adjustments below */
+ error = -EINVAL;
+ if (size < (DS_ALIGNMENT + ds_cfg.sizeof_rec[qual]))
+ goto out;
-int ds_release_bts(struct task_struct *task)
-{
- return ds_release(task, ds_bts);
-}
+ if (th != (size_t)-1) {
+ th *= ds_cfg.sizeof_rec[qual];
-int ds_release_pebs(struct task_struct *task)
-{
- return ds_release(task, ds_pebs);
-}
+ error = -EINVAL;
+ if (size <= th)
+ goto out;
+ }
-static int ds_get_index(struct task_struct *task, size_t *pos,
- enum ds_qualifier qual)
-{
- struct ds_context *context;
- unsigned long base, index;
- int error;
+ tracer->buffer = base;
+ tracer->size = size;
+ error = -ENOMEM;
context = ds_get_context(task);
- error = ds_validate_access(context, qual);
- if (error < 0)
+ if (!context)
goto out;
+ tracer->context = context;
- base = ds_get(context->ds, qual, ds_buffer_base);
- index = ds_get(context->ds, qual, ds_index);
+ ds_init_ds_trace(trace, qual, base, size, th, flags);
- error = ((index - base) / ds_cfg.sizeof_rec[qual]);
- if (pos)
- *pos = error;
+ error = 0;
out:
- ds_put_context(context);
return error;
}
-int ds_get_bts_index(struct task_struct *task, size_t *pos)
-{
- return ds_get_index(task, pos, ds_bts);
-}
-
-int ds_get_pebs_index(struct task_struct *task, size_t *pos)
+struct bts_tracer *ds_request_bts(struct task_struct *task,
+ void *base, size_t size,
+ bts_ovfl_callback_t ovfl, size_t th,
+ unsigned int flags)
{
- return ds_get_index(task, pos, ds_pebs);
-}
-
-static int ds_get_end(struct task_struct *task, size_t *pos,
- enum ds_qualifier qual)
-{
- struct ds_context *context;
- unsigned long base, end;
+ struct bts_tracer *tracer;
+ unsigned long irq;
int error;
- context = ds_get_context(task);
- error = ds_validate_access(context, qual);
- if (error < 0)
+ error = -EOPNOTSUPP;
+ if (!ds_cfg.ctl[dsf_bts])
goto out;
- base = ds_get(context->ds, qual, ds_buffer_base);
- end = ds_get(context->ds, qual, ds_absolute_maximum);
+ /* buffer overflow notification is not yet implemented */
+ error = -EOPNOTSUPP;
+ if (ovfl)
+ goto out;
- error = ((end - base) / ds_cfg.sizeof_rec[qual]);
- if (pos)
- *pos = error;
- out:
- ds_put_context(context);
- return error;
-}
+ error = -ENOMEM;
+ tracer = kzalloc(sizeof(*tracer), GFP_KERNEL);
+ if (!tracer)
+ goto out;
+ tracer->ovfl = ovfl;
-int ds_get_bts_end(struct task_struct *task, size_t *pos)
-{
- return ds_get_end(task, pos, ds_bts);
-}
+ error = ds_request(&tracer->ds, &tracer->trace.ds,
+ ds_bts, task, base, size, th, flags);
+ if (error < 0)
+ goto out_tracer;
-int ds_get_pebs_end(struct task_struct *task, size_t *pos)
-{
- return ds_get_end(task, pos, ds_pebs);
-}
-static int ds_access(struct task_struct *task, size_t index,
- const void **record, enum ds_qualifier qual)
-{
- struct ds_context *context;
- unsigned long base, idx;
- int error;
+ spin_lock_irqsave(&ds_lock, irq);
- if (!record)
- return -EINVAL;
+ error = -EPERM;
+ if (!check_tracer(task))
+ goto out_unlock;
+ get_tracer(task);
- context = ds_get_context(task);
- error = ds_validate_access(context, qual);
- if (error < 0)
- goto out;
+ error = -EPERM;
+ if (tracer->ds.context->bts_master)
+ goto out_put_tracer;
+ tracer->ds.context->bts_master = tracer;
- base = ds_get(context->ds, qual, ds_buffer_base);
- idx = base + (index * ds_cfg.sizeof_rec[qual]);
+ spin_unlock_irqrestore(&ds_lock, irq);
- error = -EINVAL;
- if (idx > ds_get(context->ds, qual, ds_absolute_maximum))
- goto out;
- *record = (const void *)idx;
- error = ds_cfg.sizeof_rec[qual];
- out:
- ds_put_context(context);
- return error;
-}
+ tracer->trace.read = bts_read;
+ tracer->trace.write = bts_write;
-int ds_access_bts(struct task_struct *task, size_t index, const void **record)
-{
- return ds_access(task, index, record, ds_bts);
-}
+ ds_write_config(tracer->ds.context, &tracer->trace.ds, ds_bts);
+ ds_resume_bts(tracer);
-int ds_access_pebs(struct task_struct *task, size_t index, const void **record)
-{
- return ds_access(task, index, record, ds_pebs);
+ return tracer;
+
+ out_put_tracer:
+ put_tracer(task);
+ out_unlock:
+ spin_unlock_irqrestore(&ds_lock, irq);
+ ds_put_context(tracer->ds.context);
+ out_tracer:
+ kfree(tracer);
+ out:
+ return ERR_PTR(error);
}
-static int ds_write(struct task_struct *task, const void *record, size_t size,
- enum ds_qualifier qual, int force)
+struct pebs_tracer *ds_request_pebs(struct task_struct *task,
+ void *base, size_t size,
+ pebs_ovfl_callback_t ovfl, size_t th,
+ unsigned int flags)
{
- struct ds_context *context;
+ struct pebs_tracer *tracer;
+ unsigned long irq;
int error;
- if (!record)
- return -EINVAL;
+ /* buffer overflow notification is not yet implemented */
+ error = -EOPNOTSUPP;
+ if (ovfl)
+ goto out;
- error = -EPERM;
- context = ds_get_context(task);
- if (!context)
+ error = -ENOMEM;
+ tracer = kzalloc(sizeof(*tracer), GFP_KERNEL);
+ if (!tracer)
goto out;
+ tracer->ovfl = ovfl;
- if (!force) {
- error = ds_validate_access(context, qual);
- if (error < 0)
- goto out;
- }
+ error = ds_request(&tracer->ds, &tracer->trace.ds,
+ ds_pebs, task, base, size, th, flags);
+ if (error < 0)
+ goto out_tracer;
- error = 0;
- while (size) {
- unsigned long base, index, end, write_end, int_th;
- unsigned long write_size, adj_write_size;
+ spin_lock_irqsave(&ds_lock, irq);
- /*
- * write as much as possible without producing an
- * overflow interrupt.
- *
- * interrupt_threshold must either be
- * - bigger than absolute_maximum or
- * - point to a record between buffer_base and absolute_maximum
- *
- * index points to a valid record.
- */
- base = ds_get(context->ds, qual, ds_buffer_base);
- index = ds_get(context->ds, qual, ds_index);
- end = ds_get(context->ds, qual, ds_absolute_maximum);
- int_th = ds_get(context->ds, qual, ds_interrupt_threshold);
+ error = -EPERM;
+ if (!check_tracer(task))
+ goto out_unlock;
+ get_tracer(task);
- write_end = min(end, int_th);
+ error = -EPERM;
+ if (tracer->ds.context->pebs_master)
+ goto out_put_tracer;
+ tracer->ds.context->pebs_master = tracer;
- /* if we are already beyond the interrupt threshold,
- * we fill the entire buffer */
- if (write_end <= index)
- write_end = end;
+ spin_unlock_irqrestore(&ds_lock, irq);
- if (write_end <= index)
- goto out;
+ ds_write_config(tracer->ds.context, &tracer->trace.ds, ds_bts);
+ ds_resume_pebs(tracer);
- write_size = min((unsigned long) size, write_end - index);
- memcpy((void *)index, record, write_size);
+ return tracer;
- record = (const char *)record + write_size;
- size -= write_size;
- error += write_size;
+ out_put_tracer:
+ put_tracer(task);
+ out_unlock:
+ spin_unlock_irqrestore(&ds_lock, irq);
+ ds_put_context(tracer->ds.context);
+ out_tracer:
+ kfree(tracer);
+ out:
+ return ERR_PTR(error);
+}
- adj_write_size = write_size / ds_cfg.sizeof_rec[qual];
- adj_write_size *= ds_cfg.sizeof_rec[qual];
+void ds_release_bts(struct bts_tracer *tracer)
+{
+ if (!tracer)
+ return;
- /* zero out trailing bytes */
- memset((char *)index + write_size, 0,
- adj_write_size - write_size);
- index += adj_write_size;
+ ds_suspend_bts(tracer);
- if (index >= end)
- index = base;
- ds_set(context->ds, qual, ds_index, index);
+ WARN_ON_ONCE(tracer->ds.context->bts_master != tracer);
+ tracer->ds.context->bts_master = NULL;
- if (index >= int_th)
- ds_overflow(task, context, qual);
- }
+ put_tracer(tracer->ds.context->task);
+ ds_put_context(tracer->ds.context);
- out:
- ds_put_context(context);
- return error;
+ kfree(tracer);
}
-int ds_write_bts(struct task_struct *task, const void *record, size_t size)
+void ds_suspend_bts(struct bts_tracer *tracer)
{
- return ds_write(task, record, size, ds_bts, /* force = */ 0);
-}
+ struct task_struct *task;
-int ds_write_pebs(struct task_struct *task, const void *record, size_t size)
-{
- return ds_write(task, record, size, ds_pebs, /* force = */ 0);
-}
+ if (!tracer)
+ return;
-int ds_unchecked_write_bts(struct task_struct *task,
- const void *record, size_t size)
-{
- return ds_write(task, record, size, ds_bts, /* force = */ 1);
-}
+ task = tracer->ds.context->task;
-int ds_unchecked_write_pebs(struct task_struct *task,
- const void *record, size_t size)
-{
- return ds_write(task, record, size, ds_pebs, /* force = */ 1);
+ if (!task || (task == current))
+ update_debugctlmsr(get_debugctlmsr() & ~BTS_CONTROL);
+
+ if (task) {
+ task->thread.debugctlmsr &= ~BTS_CONTROL;
+
+ if (!task->thread.debugctlmsr)
+ clear_tsk_thread_flag(task, TIF_DEBUGCTLMSR);
+ }
}
-static int ds_reset_or_clear(struct task_struct *task,
- enum ds_qualifier qual, int clear)
+void ds_resume_bts(struct bts_tracer *tracer)
{
- struct ds_context *context;
- unsigned long base, end;
- int error;
+ struct task_struct *task;
+ unsigned long control;
- context = ds_get_context(task);
- error = ds_validate_access(context, qual);
- if (error < 0)
- goto out;
+ if (!tracer)
+ return;
- base = ds_get(context->ds, qual, ds_buffer_base);
- end = ds_get(context->ds, qual, ds_absolute_maximum);
+ task = tracer->ds.context->task;
- if (clear)
- memset((void *)base, 0, end - base);
+ control = ds_cfg.ctl[dsf_bts];
+ if (!(tracer->trace.ds.flags & BTS_KERNEL))
+ control |= ds_cfg.ctl[dsf_bts_kernel];
+ if (!(tracer->trace.ds.flags & BTS_USER))
+ control |= ds_cfg.ctl[dsf_bts_user];
- ds_set(context->ds, qual, ds_index, base);
+ if (task) {
+ task->thread.debugctlmsr |= control;
+ set_tsk_thread_flag(task, TIF_DEBUGCTLMSR);
+ }
- error = 0;
- out:
- ds_put_context(context);
- return error;
+ if (!task || (task == current))
+ update_debugctlmsr(get_debugctlmsr() | control);
}
-int ds_reset_bts(struct task_struct *task)
+void ds_release_pebs(struct pebs_tracer *tracer)
{
- return ds_reset_or_clear(task, ds_bts, /* clear = */ 0);
+ if (!tracer)
+ return;
+
+ ds_suspend_pebs(tracer);
+
+ WARN_ON_ONCE(tracer->ds.context->pebs_master != tracer);
+ tracer->ds.context->pebs_master = NULL;
+
+ put_tracer(tracer->ds.context->task);
+ ds_put_context(tracer->ds.context);
+
+ kfree(tracer);
}
-int ds_reset_pebs(struct task_struct *task)
+void ds_suspend_pebs(struct pebs_tracer *tracer)
{
- return ds_reset_or_clear(task, ds_pebs, /* clear = */ 0);
+
}
-int ds_clear_bts(struct task_struct *task)
+void ds_resume_pebs(struct pebs_tracer *tracer)
{
- return ds_reset_or_clear(task, ds_bts, /* clear = */ 1);
+
}
-int ds_clear_pebs(struct task_struct *task)
+const struct bts_trace *ds_read_bts(struct bts_tracer *tracer)
{
- return ds_reset_or_clear(task, ds_pebs, /* clear = */ 1);
+ if (!tracer)
+ return NULL;
+
+ ds_read_config(tracer->ds.context, &tracer->trace.ds, ds_bts);
+ return &tracer->trace;
}
-int ds_get_pebs_reset(struct task_struct *task, u64 *value)
+const struct pebs_trace *ds_read_pebs(struct pebs_tracer *tracer)
{
- struct ds_context *context;
- int error;
+ if (!tracer)
+ return NULL;
+
+ ds_read_config(tracer->ds.context, &tracer->trace.ds, ds_pebs);
+ tracer->trace.reset_value =
+ *(u64 *)(tracer->ds.context->ds + (ds_cfg.sizeof_field * 8));
- if (!value)
+ return &tracer->trace;
+}
+
+int ds_reset_bts(struct bts_tracer *tracer)
+{
+ if (!tracer)
return -EINVAL;
- context = ds_get_context(task);
- error = ds_validate_access(context, ds_pebs);
- if (error < 0)
- goto out;
+ tracer->trace.ds.top = tracer->trace.ds.begin;
- *value = *(u64 *)(context->ds + (ds_cfg.sizeof_field * 8));
+ ds_set(tracer->ds.context->ds, ds_bts, ds_index,
+ (unsigned long)tracer->trace.ds.top);
- error = 0;
- out:
- ds_put_context(context);
- return error;
+ return 0;
}
-int ds_set_pebs_reset(struct task_struct *task, u64 value)
+int ds_reset_pebs(struct pebs_tracer *tracer)
{
- struct ds_context *context;
- int error;
+ if (!tracer)
+ return -EINVAL;
- context = ds_get_context(task);
- error = ds_validate_access(context, ds_pebs);
- if (error < 0)
- goto out;
+ tracer->trace.ds.top = tracer->trace.ds.begin;
- *(u64 *)(context->ds + (ds_cfg.sizeof_field * 8)) = value;
+ ds_set(tracer->ds.context->ds, ds_bts, ds_index,
+ (unsigned long)tracer->trace.ds.top);
- error = 0;
- out:
- ds_put_context(context);
- return error;
+ return 0;
+}
+
+int ds_set_pebs_reset(struct pebs_tracer *tracer, u64 value)
+{
+ if (!tracer)
+ return -EINVAL;
+
+ *(u64 *)(tracer->ds.context->ds + (ds_cfg.sizeof_field * 8)) = value;
+
+ return 0;
}
-static const struct ds_configuration ds_cfg_var = {
- .sizeof_ds = sizeof(long) * 12,
- .sizeof_field = sizeof(long),
- .sizeof_rec[ds_bts] = sizeof(long) * 3,
+static const struct ds_configuration ds_cfg_netburst = {
+ .name = "netburst",
+ .ctl[dsf_bts] = (1 << 2) | (1 << 3),
+ .ctl[dsf_bts_kernel] = (1 << 5),
+ .ctl[dsf_bts_user] = (1 << 6),
+
+ .sizeof_field = sizeof(long),
+ .sizeof_rec[ds_bts] = sizeof(long) * 3,
#ifdef __i386__
- .sizeof_rec[ds_pebs] = sizeof(long) * 10
+ .sizeof_rec[ds_pebs] = sizeof(long) * 10,
#else
- .sizeof_rec[ds_pebs] = sizeof(long) * 18
+ .sizeof_rec[ds_pebs] = sizeof(long) * 18,
#endif
};
-static const struct ds_configuration ds_cfg_64 = {
- .sizeof_ds = 8 * 12,
- .sizeof_field = 8,
- .sizeof_rec[ds_bts] = 8 * 3,
+static const struct ds_configuration ds_cfg_pentium_m = {
+ .name = "pentium m",
+ .ctl[dsf_bts] = (1 << 6) | (1 << 7),
+
+ .sizeof_field = sizeof(long),
+ .sizeof_rec[ds_bts] = sizeof(long) * 3,
#ifdef __i386__
- .sizeof_rec[ds_pebs] = 8 * 10
+ .sizeof_rec[ds_pebs] = sizeof(long) * 10,
#else
- .sizeof_rec[ds_pebs] = 8 * 18
+ .sizeof_rec[ds_pebs] = sizeof(long) * 18,
#endif
};
+static const struct ds_configuration ds_cfg_core2 = {
+ .name = "core 2",
+ .ctl[dsf_bts] = (1 << 6) | (1 << 7),
+ .ctl[dsf_bts_kernel] = (1 << 9),
+ .ctl[dsf_bts_user] = (1 << 10),
+
+ .sizeof_field = 8,
+ .sizeof_rec[ds_bts] = 8 * 3,
+ .sizeof_rec[ds_pebs] = 8 * 18,
+};
-static inline void
+static void
ds_configure(const struct ds_configuration *cfg)
{
+ memset(&ds_cfg, 0, sizeof(ds_cfg));
ds_cfg = *cfg;
+
+ printk(KERN_INFO "[ds] using %s configuration\n", ds_cfg.name);
+
+ if (!cpu_has_bts) {
+ ds_cfg.ctl[dsf_bts] = 0;
+ printk(KERN_INFO "[ds] bts not available\n");
+ }
+ if (!cpu_has_pebs)
+ printk(KERN_INFO "[ds] pebs not available\n");
+
+ WARN_ON_ONCE(MAX_SIZEOF_DS < (12 * ds_cfg.sizeof_field));
}
void __cpuinit ds_init_intel(struct cpuinfo_x86 *c)
switch (c->x86) {
case 0x6:
switch (c->x86_model) {
+ case 0 ... 0xC:
+ /* sorry, don't know about them */
+ break;
case 0xD:
case 0xE: /* Pentium M */
- ds_configure(&ds_cfg_var);
+ ds_configure(&ds_cfg_pentium_m);
break;
- case 0xF: /* Core2 */
- case 0x1C: /* Atom */
- ds_configure(&ds_cfg_64);
- break;
- default:
- /* sorry, don't know about them */
+ default: /* Core2, Atom, ... */
+ ds_configure(&ds_cfg_core2);
break;
}
break;
case 0x0:
case 0x1:
case 0x2: /* Netburst */
- ds_configure(&ds_cfg_var);
+ ds_configure(&ds_cfg_netburst);
break;
default:
/* sorry, don't know about them */
}
}
-void ds_free(struct ds_context *context)
+/*
+ * Change the DS configuration from tracing prev to tracing next.
+ */
+void ds_switch_to(struct task_struct *prev, struct task_struct *next)
+{
+ struct ds_context *prev_ctx = prev->thread.ds_ctx;
+ struct ds_context *next_ctx = next->thread.ds_ctx;
+
+ if (prev_ctx) {
+ update_debugctlmsr(0);
+
+ if (prev_ctx->bts_master &&
+ (prev_ctx->bts_master->trace.ds.flags & BTS_TIMESTAMPS)) {
+ struct bts_struct ts = {
+ .qualifier = bts_task_departs,
+ .variant.timestamp.jiffies = jiffies_64,
+ .variant.timestamp.pid = prev->pid
+ };
+ bts_write(prev_ctx->bts_master, &ts);
+ }
+ }
+
+ if (next_ctx) {
+ if (next_ctx->bts_master &&
+ (next_ctx->bts_master->trace.ds.flags & BTS_TIMESTAMPS)) {
+ struct bts_struct ts = {
+ .qualifier = bts_task_arrives,
+ .variant.timestamp.jiffies = jiffies_64,
+ .variant.timestamp.pid = next->pid
+ };
+ bts_write(next_ctx->bts_master, &ts);
+ }
+
+ wrmsrl(MSR_IA32_DS_AREA, (unsigned long)next_ctx->ds);
+ }
+
+ update_debugctlmsr(next->thread.debugctlmsr);
+}
+
+void ds_copy_thread(struct task_struct *tsk, struct task_struct *father)
+{
+ clear_tsk_thread_flag(tsk, TIF_DS_AREA_MSR);
+ tsk->thread.ds_ctx = NULL;
+}
+
+void ds_exit_thread(struct task_struct *tsk)
{
- /* This is called when the task owning the parameter context
- * is dying. There should not be any user of that context left
- * to disturb us, anymore. */
- unsigned long leftovers = context->count;
- while (leftovers--)
- ds_put_context(context);
+ WARN_ON(tsk->thread.ds_ctx);
}
projects / linux-2.6-omap-h63xx.git / blobdiff