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Diffstat (limited to 'arch/x86/kernel/ds.c')
-rw-r--r--arch/x86/kernel/ds.c81
1 files changed, 53 insertions, 28 deletions
diff --git a/arch/x86/kernel/ds.c b/arch/x86/kernel/ds.c
index 2b69994..a2d1176 100644
--- a/arch/x86/kernel/ds.c
+++ b/arch/x86/kernel/ds.c
@@ -21,8 +21,6 @@
*/
-#ifdef CONFIG_X86_DS
-
#include <asm/ds.h>
#include <linux/errno.h>
@@ -211,14 +209,15 @@ static DEFINE_PER_CPU(struct ds_context *, system_context);
static inline struct ds_context *ds_get_context(struct task_struct *task)
{
struct ds_context *context;
+ unsigned long irq;
- spin_lock(&ds_lock);
+ spin_lock_irqsave(&ds_lock, irq);
context = (task ? task->thread.ds_ctx : this_system_context);
if (context)
context->count++;
- spin_unlock(&ds_lock);
+ spin_unlock_irqrestore(&ds_lock, irq);
return context;
}
@@ -226,18 +225,16 @@ static inline struct ds_context *ds_get_context(struct task_struct *task)
/*
* Same as ds_get_context, but allocates the context and it's DS
* structure, if necessary; returns NULL; if out of memory.
- *
- * pre: requires ds_lock to be held
*/
static inline struct ds_context *ds_alloc_context(struct task_struct *task)
{
struct ds_context **p_context =
(task ? &task->thread.ds_ctx : &this_system_context);
struct ds_context *context = *p_context;
+ unsigned long irq;
if (!context) {
context = kzalloc(sizeof(*context), GFP_KERNEL);
-
if (!context)
return NULL;
@@ -247,18 +244,27 @@ static inline struct ds_context *ds_alloc_context(struct task_struct *task)
return NULL;
}
- *p_context = context;
+ spin_lock_irqsave(&ds_lock, irq);
- context->this = p_context;
- context->task = task;
+ if (*p_context) {
+ kfree(context->ds);
+ kfree(context);
+
+ context = *p_context;
+ } else {
+ *p_context = context;
- if (task)
- set_tsk_thread_flag(task, TIF_DS_AREA_MSR);
+ context->this = p_context;
+ context->task = task;
- if (!task || (task == current))
- wrmsr(MSR_IA32_DS_AREA, (unsigned long)context->ds, 0);
+ if (task)
+ set_tsk_thread_flag(task, TIF_DS_AREA_MSR);
- get_tracer(task);
+ if (!task || (task == current))
+ wrmsrl(MSR_IA32_DS_AREA,
+ (unsigned long)context->ds);
+ }
+ spin_unlock_irqrestore(&ds_lock, irq);
}
context->count++;
@@ -272,10 +278,12 @@ static inline struct ds_context *ds_alloc_context(struct task_struct *task)
*/
static inline void ds_put_context(struct ds_context *context)
{
+ unsigned long irq;
+
if (!context)
return;
- spin_lock(&ds_lock);
+ spin_lock_irqsave(&ds_lock, irq);
if (--context->count)
goto out;
@@ -297,7 +305,7 @@ static inline void ds_put_context(struct ds_context *context)
kfree(context->ds);
kfree(context);
out:
- spin_unlock(&ds_lock);
+ spin_unlock_irqrestore(&ds_lock, irq);
}
@@ -368,6 +376,7 @@ static int ds_request(struct task_struct *task, void *base, size_t size,
struct ds_context *context;
unsigned long buffer, adj;
const unsigned long alignment = (1 << 3);
+ unsigned long irq;
int error = 0;
if (!ds_cfg.sizeof_ds)
@@ -382,25 +391,27 @@ static int ds_request(struct task_struct *task, void *base, size_t size,
return -EOPNOTSUPP;
- spin_lock(&ds_lock);
-
- if (!check_tracer(task))
- return -EPERM;
-
- error = -ENOMEM;
context = ds_alloc_context(task);
if (!context)
+ return -ENOMEM;
+
+ spin_lock_irqsave(&ds_lock, irq);
+
+ error = -EPERM;
+ if (!check_tracer(task))
goto out_unlock;
+ get_tracer(task);
+
error = -EALREADY;
if (context->owner[qual] == current)
- goto out_unlock;
+ goto out_put_tracer;
error = -EPERM;
if (context->owner[qual] != NULL)
- goto out_unlock;
+ goto out_put_tracer;
context->owner[qual] = current;
- spin_unlock(&ds_lock);
+ spin_unlock_irqrestore(&ds_lock, irq);
error = -ENOMEM;
@@ -448,10 +459,17 @@ static int ds_request(struct task_struct *task, void *base, size_t size,
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;
out_unlock:
- spin_unlock(&ds_lock);
+ spin_unlock_irqrestore(&ds_lock, irq);
ds_put_context(context);
return error;
}
@@ -801,13 +819,21 @@ static const struct ds_configuration ds_cfg_var = {
.sizeof_ds = sizeof(long) * 12,
.sizeof_field = sizeof(long),
.sizeof_rec[ds_bts] = sizeof(long) * 3,
+#ifdef __i386__
.sizeof_rec[ds_pebs] = sizeof(long) * 10
+#else
+ .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,
+#ifdef __i386__
.sizeof_rec[ds_pebs] = 8 * 10
+#else
+ .sizeof_rec[ds_pebs] = 8 * 18
+#endif
};
static inline void
@@ -861,4 +887,3 @@ void ds_free(struct ds_context *context)
while (leftovers--)
ds_put_context(context);
}
-#endif /* CONFIG_X86_DS */
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