1 files changed, 42 insertions, 2 deletions
diff --git a/scripts/gdb/linux/cpus.py b/scripts/gdb/linux/cpus.py
index 008e62f3190d..cba589e5b57d 100644
--- a/scripts/gdb/linux/cpus.py
+++ b/scripts/gdb/linux/cpus.py
@@ -16,6 +16,9 @@ import gdb
 from linux import tasks, utils
 
 
+task_type = utils.CachedType("struct task_struct")
+
+
 MAX_CPUS = 4096
 
 
@@ -156,6 +159,44 @@ Note that VAR has to be quoted as string."""
 
 PerCpu()
 
+def get_current_task(cpu):
+    task_ptr_type = task_type.get_type().pointer()
+
+    if utils.is_target_arch("x86"):
+        if gdb.lookup_global_symbol("cpu_tasks"):
+            # This is a UML kernel, which stores the current task
+            # differently than other x86 sub architectures
+            var_ptr = gdb.parse_and_eval("(struct task_struct *)cpu_tasks[0].task")
+            return var_ptr.dereference()
+        else:
+            var_ptr = gdb.parse_and_eval("&pcpu_hot.current_task")
+            return per_cpu(var_ptr, cpu).dereference()
+    elif utils.is_target_arch("aarch64"):
+        current_task_addr = gdb.parse_and_eval("$SP_EL0")
+        if (current_task_addr >> 63) != 0:
+            current_task = current_task_addr.cast(task_ptr_type)
+            return current_task.dereference()
+        else:
+            raise gdb.GdbError("Sorry, obtaining the current task is not allowed "
+                               "while running in userspace(EL0)")
+    elif utils.is_target_arch("riscv"):
+        current_tp = gdb.parse_and_eval("$tp")
+        scratch_reg = gdb.parse_and_eval("$sscratch")
+
+        # by default tp points to current task
+        current_task = current_tp.cast(task_ptr_type)
+
+        # scratch register is set 0 in trap handler after entering kernel.
+        # When hart is in user mode, scratch register is pointing to task_struct.
+        # and tp is used by user mode. So when scratch register holds larger value
+        # (negative address as ulong is larger value) than tp, then use scratch register.
+        if (scratch_reg.cast(utils.get_ulong_type()) > current_tp.cast(utils.get_ulong_type())):
+            current_task = scratch_reg.cast(task_ptr_type)
+
+        return current_task.dereference()
+    else:
+        raise gdb.GdbError("Sorry, obtaining the current task is not yet "
+                           "supported with this arch")
 
 class LxCurrentFunc(gdb.Function):
     """Return current task.
@@ -167,8 +208,7 @@ number. If CPU is omitted, the CPU of the current context is used."""
         super(LxCurrentFunc, self).__init__("lx_current")
 
     def invoke(self, cpu=-1):
-        var_ptr = gdb.parse_and_eval("&current_task")
-        return per_cpu(var_ptr, cpu).dereference()
+        return get_current_task(cpu)
 
 
 LxCurrentFunc()