1 files changed, 227 insertions, 0 deletions
diff --git a/scripts/gdb/linux/cpus.py b/scripts/gdb/linux/cpus.py
new file mode 100644
index 000000000000..6edf4ef61636
--- /dev/null
+++ b/scripts/gdb/linux/cpus.py
@@ -0,0 +1,227 @@
+#
+# gdb helper commands and functions for Linux kernel debugging
+#
+#  per-cpu tools
+#
+# Copyright (c) Siemens AG, 2011-2013
+#
+# Authors:
+#  Jan Kiszka <jan.kiszka@siemens.com>
+#
+# This work is licensed under the terms of the GNU GPL version 2.
+#
+
+import gdb
+
+from linux import tasks, utils
+
+
+task_type = utils.CachedType("struct task_struct")
+
+
+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:
+        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.")
+
+
+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(
+            "trap_block[{0}].__per_cpu_base".format(str(cpu)))
+    else:
+        try:
+            offset = gdb.parse_and_eval(
+                "__per_cpu_offset[{0}]".format(str(cpu)))
+        except gdb.error:
+            # !CONFIG_SMP case
+            offset = 0
+    pointer = var_ptr.cast(utils.get_long_type()) + offset
+    return pointer.cast(var_ptr.type)
+
+
+cpu_mask = {}
+
+
+def cpu_mask_invalidate(event):
+    global cpu_mask
+    cpu_mask = {}
+    gdb.events.stop.disconnect(cpu_mask_invalidate)
+    if hasattr(gdb.events, 'new_objfile'):
+        gdb.events.new_objfile.disconnect(cpu_mask_invalidate)
+
+
+def cpu_list(mask_name):
+    global cpu_mask
+    mask = None
+    if mask_name in cpu_mask:
+        mask = cpu_mask[mask_name]
+    if mask is None:
+        mask = gdb.parse_and_eval(mask_name + ".bits")
+        if hasattr(gdb, 'events'):
+            cpu_mask[mask_name] = mask
+            gdb.events.stop.connect(cpu_mask_invalidate)
+            if hasattr(gdb.events, 'new_objfile'):
+                gdb.events.new_objfile.connect(cpu_mask_invalidate)
+    bits_per_entry = mask[0].type.sizeof * 8
+    num_entries = mask.type.sizeof * 8 / bits_per_entry
+    entry = -1
+    bits = 0
+
+    while True:
+        while bits == 0:
+            entry += 1
+            if entry == num_entries:
+                return
+            bits = mask[entry]
+            if bits != 0:
+                bit = 0
+                break
+
+        while bits & 1 == 0:
+            bits >>= 1
+            bit += 1
+
+        cpu = entry * bits_per_entry + bit
+
+        bits >>= 1
+        bit += 1
+
+        yield int(cpu)
+
+
+def each_online_cpu():
+    for cpu in cpu_list("__cpu_online_mask"):
+        yield cpu
+
+
+def each_present_cpu():
+    for cpu in cpu_list("__cpu_present_mask"):
+        yield cpu
+
+
+def each_possible_cpu():
+    for cpu in cpu_list("__cpu_possible_mask"):
+        yield cpu
+
+
+def each_active_cpu():
+    for cpu in cpu_list("__cpu_active_mask"):
+        yield cpu
+
+
+class LxCpus(gdb.Command):
+    """List CPU status arrays
+
+Displays the known state of each CPU based on the kernel masks
+and can help identify the state of hotplugged CPUs"""
+
+    def __init__(self):
+        super(LxCpus, self).__init__("lx-cpus", gdb.COMMAND_DATA)
+
+    def invoke(self, arg, from_tty):
+        gdb.write("Possible CPUs : {}\n".format(list(each_possible_cpu())))
+        gdb.write("Present CPUs  : {}\n".format(list(each_present_cpu())))
+        gdb.write("Online CPUs   : {}\n".format(list(each_online_cpu())))
+        gdb.write("Active CPUs   : {}\n".format(list(each_active_cpu())))
+
+
+LxCpus()
+
+
+class PerCpu(gdb.Function):
+    """Return per-cpu variable.
+
+$lx_per_cpu(VAR[, CPU]): Return the per-cpu variable called VAR for the
+given CPU number. If CPU is omitted, the CPU of the current context is used.
+Note that VAR has to be quoted as string."""
+
+    def __init__(self):
+        super(PerCpu, self).__init__("lx_per_cpu")
+
+    def invoke(self, var, cpu=-1):
+        return per_cpu(var.address, cpu).dereference()
+
+
+PerCpu()
+
+
+class PerCpuPtr(gdb.Function):
+    """Return per-cpu pointer.
+
+$lx_per_cpu_ptr(VAR[, CPU]): Return the per-cpu pointer 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(PerCpuPtr, self).__init__("lx_per_cpu_ptr")
+
+    def invoke(self, var, cpu=-1):
+        return per_cpu(var, cpu)
+
+
+PerCpuPtr()
+
+
+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("&current_task")
+            return per_cpu(var_ptr, cpu).dereference()
+    elif utils.is_target_arch("aarch64"):
+        current_task_addr = gdb.parse_and_eval("(unsigned long)$SP_EL0")
+        if (current_task_addr >> 63) != 0:
+            current_task = current_task_addr.cast(task_ptr_type)
+            return current_task.dereference()
+        else:
+            raise gdb.GdbError("Sorry, obtaining the current task is not allowed "
+                               "while running in userspace(EL0)")
+    elif utils.is_target_arch("riscv"):
+        current_tp = gdb.parse_and_eval("$tp")
+        scratch_reg = gdb.parse_and_eval("$sscratch")
+
+        # by default tp points to current task
+        current_task = current_tp.cast(task_ptr_type)
+
+        # scratch register is set 0 in trap handler after entering kernel.
+        # When hart is in user mode, scratch register is pointing to task_struct.
+        # and tp is used by user mode. So when scratch register holds larger value
+        # (negative address as ulong is larger value) than tp, then use scratch register.
+        if (scratch_reg.cast(utils.get_ulong_type()) > current_tp.cast(utils.get_ulong_type())):
+            current_task = scratch_reg.cast(task_ptr_type)
+
+        return current_task.dereference()
+    else:
+        raise gdb.GdbError("Sorry, obtaining the current task is not yet "
+                           "supported with this arch")
+
+class LxCurrentFunc(gdb.Function):
+    """Return current task.
+
+$lx_current([CPU]): Return the per-cpu task variable for the given CPU
+number. If CPU is omitted, the CPU of the current context is used."""
+
+    def __init__(self):
+        super(LxCurrentFunc, self).__init__("lx_current")
+
+    def invoke(self, cpu=-1):
+        return get_current_task(cpu)
+
+
+LxCurrentFunc()