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>

arch/arm64/kernel/ptrace.c

@@ -132,7 +132,7 @@ static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
 {
 	return ((addr & ~(THREAD_SIZE - 1))  ==
 		(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1))) ||
-		on_irq_stack(addr);
+		on_irq_stack(addr, NULL);
 }
 
 /**

arch/arm64/kernel/sdei.c

@@ -13,6 +13,7 @@
 #include <asm/mmu.h>
 #include <asm/ptrace.h>
 #include <asm/sections.h>
+#include <asm/stacktrace.h>
 #include <asm/sysreg.h>
 #include <asm/vmap_stack.h>
 
@@ -88,23 +89,55 @@ static int init_sdei_stacks(void)
 	return err;
 }
 
-bool _on_sdei_stack(unsigned long sp)
+bool on_sdei_normal_stack(unsigned long sp,
+			struct stack_info *info)
 {
-	unsigned long low, high;
+	unsigned long low = (unsigned long)raw_cpu_read(sdei_stack_normal_ptr);
+	unsigned long high = low + SDEI_STACK_SIZE;
 
+	if (sp < low || sp >= high)
+		return false;
+
+	if (info) {
+		info->low = low;
+		info->high = high;
+		info->type = STACK_TYPE_SDEI_NORMAL;
+	}
+
+	return true;
+}
+
+bool on_sdei_critical_stack(unsigned long sp,
+			struct stack_info *info)
+{
+	unsigned long low = (unsigned long)raw_cpu_read(sdei_stack_critical_ptr);
+	unsigned long high = low + SDEI_STACK_SIZE;
+
+	if (sp < low || sp >= high)
+		return false;
+
+	if (info) {
+		info->low = low;
+		info->high = high;
+		info->type = STACK_TYPE_SDEI_CRITICAL;
+	}
+
+	return true;
+}
+
+bool _on_sdei_stack(unsigned long sp,
+		struct stack_info *info)
+{
 	if (!IS_ENABLED(CONFIG_VMAP_STACK))
 		return false;
 
-	low = (unsigned long)raw_cpu_read(sdei_stack_critical_ptr);
-	high = low + SDEI_STACK_SIZE;
-
-	if (low <= sp && sp < high)
+	if (on_sdei_critical_stack(sp, info))
 		return true;
 
-	low = (unsigned long)raw_cpu_read(sdei_stack_normal_ptr);
-	high = low + SDEI_STACK_SIZE;
+	if (on_sdei_normal_stack(sp, info))
+		return true;
 
-	return (low <= sp && sp < high);
+	return false;
 }
 
 unsigned long sdei_arch_get_entry_point(int conduit)

arch/arm64/kernel/stacktrace.c

@@ -50,7 +50,7 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
 	if (!tsk)
 		tsk = current;
 
-	if (!on_accessible_stack(tsk, fp))
+	if (!on_accessible_stack(tsk, fp, NULL))
 		return -EINVAL;
 
 	frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp));