forked from mirrors/linux
fe7f9ed98d
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 <jan.kiszka@siemens.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ben Widawsky <ben@bwidawsk.net> Cc: Borislav Petkov <bp@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
68 lines
1.8 KiB
Python
68 lines
1.8 KiB
Python
#
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# gdb helper commands and functions for Linux kernel debugging
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#
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# per-cpu tools
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#
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# Copyright (c) Siemens AG, 2011-2013
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#
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# Authors:
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# Jan Kiszka <jan.kiszka@siemens.com>
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#
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# This work is licensed under the terms of the GNU GPL version 2.
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#
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import gdb
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from linux import tasks, utils
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MAX_CPUS = 4096
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def get_current_cpu():
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if utils.get_gdbserver_type() == utils.GDBSERVER_QEMU:
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return gdb.selected_thread().num - 1
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elif utils.get_gdbserver_type() == utils.GDBSERVER_KGDB:
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tid = gdb.selected_thread().ptid[2]
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if tid > (0x100000000 - MAX_CPUS - 2):
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return 0x100000000 - tid - 2
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else:
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return tasks.get_thread_info(tasks.get_task_by_pid(tid))['cpu']
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else:
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raise gdb.GdbError("Sorry, obtaining the current CPU is not yet "
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"supported with this gdb server.")
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def per_cpu(var_ptr, cpu):
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if cpu == -1:
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cpu = get_current_cpu()
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if utils.is_target_arch("sparc:v9"):
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offset = gdb.parse_and_eval(
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"trap_block[{0}].__per_cpu_base".format(str(cpu)))
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else:
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try:
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offset = gdb.parse_and_eval(
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"__per_cpu_offset[{0}]".format(str(cpu)))
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except gdb.error:
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# !CONFIG_SMP case
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offset = 0
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pointer = var_ptr.cast(utils.get_long_type()) + offset
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return pointer.cast(var_ptr.type).dereference()
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class PerCpu(gdb.Function):
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"""Return per-cpu variable.
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$lx_per_cpu("VAR"[, CPU]): Return the per-cpu variable called VAR for the
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given CPU number. If CPU is omitted, the CPU of the current context is used.
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Note that VAR has to be quoted as string."""
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def __init__(self):
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super(PerCpu, self).__init__("lx_per_cpu")
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def invoke(self, var_name, cpu=-1):
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var_ptr = gdb.parse_and_eval("&" + var_name.string())
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return per_cpu(var_ptr, cpu)
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PerCpu()
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