arm64: Add stack information to on_accessible_stack

In preparation for enabling the stackleak plugin on arm64,
we need a way to get the bounds of the current stack. Extend
on_accessible_stack to get this information.

Acked-by: Alexander Popov <alex.popov@linux.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Laura Abbott <labbott@redhat.com>
[will: folded in fix for allmodconfig build breakage w/ sdei]
Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 61 insertions, 12 deletions

diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h
index 902f9edacbea..e86737b7c924 100644
--- a/arch/arm64/include/asm/stacktrace.h
+++ b/arch/arm64/include/asm/stacktrace.h
@@ -32,6 +32,21 @@ struct stackframe {
 #endif
 };
 
+enum stack_type {
+	STACK_TYPE_UNKNOWN,
+	STACK_TYPE_TASK,
+	STACK_TYPE_IRQ,
+	STACK_TYPE_OVERFLOW,
+	STACK_TYPE_SDEI_NORMAL,
+	STACK_TYPE_SDEI_CRITICAL,
+};
+
+struct stack_info {
+	unsigned long low;
+	unsigned long high;
+	enum stack_type type;
+};
+
 extern int unwind_frame(struct task_struct *tsk, struct stackframe *frame);
 extern void walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
 			    int (*fn)(struct stackframe *, void *), void *data);
@@ -39,7 +54,8 @@ extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk);
 
 DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
 
-static inline bool on_irq_stack(unsigned long sp)
+static inline bool on_irq_stack(unsigned long sp,
+				struct stack_info *info)
 {
 	unsigned long low = (unsigned long)raw_cpu_read(irq_stack_ptr);
 	unsigned long high = low + IRQ_STACK_SIZE;
@@ -47,46 +63,79 @@ static inline bool on_irq_stack(unsigned long sp)
 	if (!low)
 		return false;
 
-	return (low <= sp && sp < high);
+	if (sp < low || sp >= high)
+		return false;
+
+	if (info) {
+		info->low = low;
+		info->high = high;
+		info->type = STACK_TYPE_IRQ;
+	}
+
+	return true;
 }
 
-static inline bool on_task_stack(struct task_struct *tsk, unsigned long sp)
+static inline bool on_task_stack(struct task_struct *tsk, unsigned long sp,
+				struct stack_info *info)
 {
 	unsigned long low = (unsigned long)task_stack_page(tsk);
 	unsigned long high = low + THREAD_SIZE;
 
-	return (low <= sp && sp < high);
+	if (sp < low || sp >= high)
+		return false;
+
+	if (info) {
+		info->low = low;
+		info->high = high;
+		info->type = STACK_TYPE_TASK;
+	}
+
+	return true;
 }
 
 #ifdef CONFIG_VMAP_STACK
 DECLARE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack);
 
-static inline bool on_overflow_stack(unsigned long sp)
+static inline bool on_overflow_stack(unsigned long sp,
+				struct stack_info *info)
 {
 	unsigned long low = (unsigned long)raw_cpu_ptr(overflow_stack);
 	unsigned long high = low + OVERFLOW_STACK_SIZE;
 
-	return (low <= sp && sp < high);
+	if (sp < low || sp >= high)
+		return false;
+
+	if (info) {
+		info->low = low;
+		info->high = high;
+		info->type = STACK_TYPE_OVERFLOW;
+	}
+
+	return true;
 }
 #else
-static inline bool on_overflow_stack(unsigned long sp) { return false; }
+static inline bool on_overflow_stack(unsigned long sp,
+			struct stack_info *info) { return false; }
 #endif
 
+
 /*
  * We can only safely access per-cpu stacks from current in a non-preemptible
  * context.
  */
-static inline bool on_accessible_stack(struct task_struct *tsk, unsigned long sp)
+static inline bool on_accessible_stack(struct task_struct *tsk,
+					unsigned long sp,
+					struct stack_info *info)
 {
-	if (on_task_stack(tsk, sp))
+	if (on_task_stack(tsk, sp, info))
 		return true;
 	if (tsk != current || preemptible())
 		return false;
-	if (on_irq_stack(sp))
+	if (on_irq_stack(sp, info))
 		return true;
-	if (on_overflow_stack(sp))
+	if (on_overflow_stack(sp, info))
 		return true;
-	if (on_sdei_stack(sp))
+	if (on_sdei_stack(sp, info))
 		return true;
 
 	return false;