diff options
| author | Florian Rommel <mail@florommel.de> | 2024-04-25 17:35:01 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-05-08 08:41:28 -0700 |
| commit | 40eea5abbb9ccae6df55dfd94c3c85c023e2521b (patch) | |
| tree | 19ca37ca7816fd808fafd27d3fcd2443ccc7ad3a /scripts/gdb | |
| parent | 7566b063e9e4af908123ebe8b80cc0d0c7429507 (diff) | |
scripts/gdb: fix detection of current CPU in KGDB
Directly read the current CPU number from the kgdb_active variable.
Before, the active CPU was obtained through the current task, which
required searching the task list for the pid of GDB's selected thread.
Obtaining the pid was buggy: GDB may use selected_thread().ptid[1] (LWPID)
instead of .ptid[2] (TID) to store the threads pid; see
https://sourceware.org/gdb/current/onlinedocs/gdb.html/Threads-In-Python.html
As a result, the detection could return the wrong CPU number, leading to
incorrect results for $lx_per_cpu and $lx_current.
As a side effect, the patch significantly speeds up $lx_per_cpu and
$lx_current in KGDB by avoiding the task-list iteration.
Link: https://lkml.kernel.org/r/20240425153501.749966-5-mail@florommel.de
Signed-off-by: Florian Rommel <mail@florommel.de>
Cc: Andrew Jones <ajones@ventanamicro.com>
Cc: Deepak Gupta <debug@rivosinc.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'scripts/gdb')
| -rw-r--r-- | scripts/gdb/linux/cpus.py | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/scripts/gdb/linux/cpus.py b/scripts/gdb/linux/cpus.py index 2b51a3abd363..2f11c4f9c345 100644 --- a/scripts/gdb/linux/cpus.py +++ b/scripts/gdb/linux/cpus.py @@ -26,11 +26,7 @@ def get_current_cpu(): if utils.get_gdbserver_type() == utils.GDBSERVER_QEMU: return gdb.selected_thread().num - 1 elif utils.get_gdbserver_type() == utils.GDBSERVER_KGDB: - tid = gdb.selected_thread().ptid[2] - if tid > (0x100000000 - MAX_CPUS - 2): - return 0x100000000 - tid - 2 - else: - return tasks.get_thread_info(tasks.get_task_by_pid(tid))['cpu'] + return gdb.parse_and_eval("kgdb_active.counter") else: raise gdb.GdbError("Sorry, obtaining the current CPU is not yet " "supported with this gdb server.") |