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-rw-r--r--arch/x86/kernel/ptrace.c57
-rw-r--r--include/linux/hw_breakpoint.h4
-rw-r--r--include/linux/perf_event.h5
-rw-r--r--kernel/hw_breakpoint.c42
-rw-r--r--kernel/perf_event.c4
5 files changed, 66 insertions, 46 deletions
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index b361d28..7079dda 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -595,7 +595,7 @@ static unsigned long ptrace_get_dr7(struct perf_event *bp[])
return dr7;
}
-static struct perf_event *
+static int
ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
struct task_struct *tsk, int disabled)
{
@@ -609,11 +609,11 @@ ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
* written the address register first
*/
if (!bp)
- return ERR_PTR(-EINVAL);
+ return -EINVAL;
err = arch_bp_generic_fields(len, type, &gen_len, &gen_type);
if (err)
- return ERR_PTR(err);
+ return err;
attr = bp->attr;
attr.bp_len = gen_len;
@@ -658,28 +658,17 @@ restore:
if (!second_pass)
continue;
- thread->ptrace_bps[i] = NULL;
- bp = ptrace_modify_breakpoint(bp, len, type,
+ rc = ptrace_modify_breakpoint(bp, len, type,
tsk, 1);
- if (IS_ERR(bp)) {
- rc = PTR_ERR(bp);
- thread->ptrace_bps[i] = NULL;
+ if (rc)
break;
- }
- thread->ptrace_bps[i] = bp;
}
continue;
}
- bp = ptrace_modify_breakpoint(bp, len, type, tsk, 0);
-
- /* Incorrect bp, or we have a bug in bp API */
- if (IS_ERR(bp)) {
- rc = PTR_ERR(bp);
- thread->ptrace_bps[i] = NULL;
+ rc = ptrace_modify_breakpoint(bp, len, type, tsk, 0);
+ if (rc)
break;
- }
- thread->ptrace_bps[i] = bp;
}
/*
* Make a second pass to free the remaining unused breakpoints
@@ -737,26 +726,32 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
attr.disabled = 1;
bp = register_user_hw_breakpoint(&attr, ptrace_triggered, tsk);
+
+ /*
+ * CHECKME: the previous code returned -EIO if the addr wasn't
+ * a valid task virtual addr. The new one will return -EINVAL in
+ * this case.
+ * -EINVAL may be what we want for in-kernel breakpoints users,
+ * but -EIO looks better for ptrace, since we refuse a register
+ * writing for the user. And anyway this is the previous
+ * behaviour.
+ */
+ if (IS_ERR(bp))
+ return PTR_ERR(bp);
+
+ t->ptrace_bps[nr] = bp;
} else {
+ int err;
+
bp = t->ptrace_bps[nr];
- t->ptrace_bps[nr] = NULL;
attr = bp->attr;
attr.bp_addr = addr;
- bp = modify_user_hw_breakpoint(bp, &attr);
+ err = modify_user_hw_breakpoint(bp, &attr);
+ if (err)
+ return err;
}
- /*
- * CHECKME: the previous code returned -EIO if the addr wasn't a
- * valid task virtual addr. The new one will return -EINVAL in this
- * case.
- * -EINVAL may be what we want for in-kernel breakpoints users, but
- * -EIO looks better for ptrace, since we refuse a register writing
- * for the user. And anyway this is the previous behaviour.
- */
- if (IS_ERR(bp))
- return PTR_ERR(bp);
- t->ptrace_bps[nr] = bp;
return 0;
}
diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h
index 42da1ce..69f07a9 100644
--- a/include/linux/hw_breakpoint.h
+++ b/include/linux/hw_breakpoint.h
@@ -55,7 +55,7 @@ register_user_hw_breakpoint(struct perf_event_attr *attr,
struct task_struct *tsk);
/* FIXME: only change from the attr, and don't unregister */
-extern struct perf_event *
+extern int
modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr);
/*
@@ -91,7 +91,7 @@ static inline struct perf_event *
register_user_hw_breakpoint(struct perf_event_attr *attr,
perf_overflow_handler_t triggered,
struct task_struct *tsk) { return NULL; }
-static inline struct perf_event *
+static inline int
modify_user_hw_breakpoint(struct perf_event *bp,
struct perf_event_attr *attr) { return NULL; }
static inline struct perf_event *
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index bf33294..64a53f7 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -872,6 +872,8 @@ extern void perf_output_copy(struct perf_output_handle *handle,
const void *buf, unsigned int len);
extern int perf_swevent_get_recursion_context(void);
extern void perf_swevent_put_recursion_context(int rctx);
+extern void perf_event_enable(struct perf_event *event);
+extern void perf_event_disable(struct perf_event *event);
#else
static inline void
perf_event_task_sched_in(struct task_struct *task, int cpu) { }
@@ -902,7 +904,8 @@ static inline void perf_event_fork(struct task_struct *tsk) { }
static inline void perf_event_init(void) { }
static inline int perf_swevent_get_recursion_context(void) { return -1; }
static inline void perf_swevent_put_recursion_context(int rctx) { }
-
+static inline void perf_event_enable(struct perf_event *event) { }
+static inline void perf_event_disable(struct perf_event *event) { }
#endif
#define perf_output_put(handle, x) \
diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c
index 03a0773..366eedf 100644
--- a/kernel/hw_breakpoint.c
+++ b/kernel/hw_breakpoint.c
@@ -320,18 +320,40 @@ EXPORT_SYMBOL_GPL(register_user_hw_breakpoint);
* @triggered: callback to trigger when we hit the breakpoint
* @tsk: pointer to 'task_struct' of the process to which the address belongs
*/
-struct perf_event *
-modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr)
+int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr)
{
- /*
- * FIXME: do it without unregistering
- * - We don't want to lose our slot
- * - If the new bp is incorrect, don't lose the older one
- */
- unregister_hw_breakpoint(bp);
+ u64 old_addr = bp->attr.bp_addr;
+ int old_type = bp->attr.bp_type;
+ int old_len = bp->attr.bp_len;
+ int err = 0;
+
+ perf_event_disable(bp);
+
+ bp->attr.bp_addr = attr->bp_addr;
+ bp->attr.bp_type = attr->bp_type;
+ bp->attr.bp_len = attr->bp_len;
+
+ if (attr->disabled)
+ goto end;
- return perf_event_create_kernel_counter(attr, -1, bp->ctx->task->pid,
- bp->overflow_handler);
+ err = arch_validate_hwbkpt_settings(bp, bp->ctx->task);
+ if (!err)
+ perf_event_enable(bp);
+
+ if (err) {
+ bp->attr.bp_addr = old_addr;
+ bp->attr.bp_type = old_type;
+ bp->attr.bp_len = old_len;
+ if (!bp->attr.disabled)
+ perf_event_enable(bp);
+
+ return err;
+ }
+
+end:
+ bp->attr.disabled = attr->disabled;
+
+ return 0;
}
EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint);
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index fd43ff4..3b0cf86 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -567,7 +567,7 @@ static void __perf_event_disable(void *info)
* is the current context on this CPU and preemption is disabled,
* hence we can't get into perf_event_task_sched_out for this context.
*/
-static void perf_event_disable(struct perf_event *event)
+void perf_event_disable(struct perf_event *event)
{
struct perf_event_context *ctx = event->ctx;
struct task_struct *task = ctx->task;
@@ -971,7 +971,7 @@ static void __perf_event_enable(void *info)
* perf_event_for_each_child or perf_event_for_each as described
* for perf_event_disable.
*/
-static void perf_event_enable(struct perf_event *event)
+void perf_event_enable(struct perf_event *event)
{
struct perf_event_context *ctx = event->ctx;
struct task_struct *task = ctx->task;
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