Commit fe7f9ed9 authored by Jan Kiszka's avatar Jan Kiszka Committed by Linus Torvalds
Browse files

scripts/gdb: add internal helper and convenience function for per-cpu lookup

This function allows to obtain a per-cpu variable, either of the current
or an explicitly specified CPU.

Note: sparc64 version is untested.
Signed-off-by: Jan Kiszka's avatarJan Kiszka <>
Cc: "David S. Miller" <>
Cc: Thomas Gleixner <>
Cc: Jason Wessel <>
Cc: Andi Kleen <>
Cc: Ben Widawsky <>
Cc: Borislav Petkov <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent a4d86792
# gdb helper commands and functions for Linux kernel debugging
# per-cpu tools
# Copyright (c) Siemens AG, 2011-2013
# Authors:
# Jan Kiszka <>
# This work is licensed under the terms of the GNU GPL version 2.
import gdb
from linux import tasks, utils
MAX_CPUS = 4096
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
return tasks.get_thread_info(tasks.get_task_by_pid(tid))['cpu']
raise gdb.GdbError("Sorry, obtaining the current CPU is not yet "
"supported with this gdb server.")
def per_cpu(var_ptr, cpu):
if cpu == -1:
cpu = get_current_cpu()
if utils.is_target_arch("sparc:v9"):
offset = gdb.parse_and_eval(
offset = gdb.parse_and_eval(
except gdb.error:
# !CONFIG_SMP case
offset = 0
pointer = var_ptr.cast(utils.get_long_type()) + offset
return pointer.cast(var_ptr.type).dereference()
class PerCpu(gdb.Function):
"""Return per-cpu variable.
$lx_per_cpu("VAR"[, CPU]): Return the per-cpu variable called VAR for the
given CPU number. If CPU is omitted, the CPU of the current context is used.
Note that VAR has to be quoted as string."""
def __init__(self):
super(PerCpu, self).__init__("lx_per_cpu")
def invoke(self, var_name, cpu=-1):
var_ptr = gdb.parse_and_eval("&" + var_name.string())
return per_cpu(var_ptr, cpu)
......@@ -27,3 +27,4 @@ else:
import linux.modules
import linux.dmesg
import linux.tasks
import linux.cpus
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