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Subject[PATCH v2 2/2] scripts/gdb: Support getting current task struct in UML
Date
A running x86 UML kernel reports with architecture "i386:x86-64" as
it is a sub-architecture. However, a difference with bare-metal x86
kernels is in how it manages tasks and the current task struct. To
identify that the inferior is a UML kernel and not bare-metal, check
for the existence of the UML specific symbol "cpu_tasks" which
contains the current task struct.

Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
---
scripts/gdb/linux/cpus.py | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/scripts/gdb/linux/cpus.py b/scripts/gdb/linux/cpus.py
index 3e02a1866751..4b4ce6464dee 100644
--- a/scripts/gdb/linux/cpus.py
+++ b/scripts/gdb/linux/cpus.py
@@ -163,8 +163,14 @@ def get_current_task(cpu):
task_ptr_type = task_type.get_type().pointer()

if utils.is_target_arch("x86"):
- var_ptr = gdb.parse_and_eval("&current_task")
- return per_cpu(var_ptr, cpu).dereference()
+ 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("&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:
--
2.30.2
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