iommulib.py

# Copyright (c) 2014, The Linux Foundation. All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 and
# only version 2 as published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

import rb_tree
import linux_list as llist

class Domain(object):
    def __init__(self, domain_num, pg_table, redirect, ctx_list, client_name):
        self.domain_num = domain_num
        self.pg_table = pg_table
        self.redirect = redirect
        self.ctx_list = ctx_list
        self.client_name = client_name

    def __repr__(self):
        return "#%d: %s" % (self.domain_num, self.client_name)

class IommuLib(object):
    def __init__(self, ramdump):
        self.ramdump = ramdump
        self.domain_list = []

        root = self.ramdump.read_word('domain_root')
        if root is None:
            return
        rb_walker = rb_tree.RbTreeWalker(self.ramdump)
        rb_walker.walk(root, self._iommu_domain_func, self.domain_list)

    def _iommu_list_func(self, node, ctx_list):
        ctx_drvdata_name_ptr = self.ramdump.read_word(
            node + self.ramdump.field_offset('struct msm_iommu_ctx_drvdata', 'name'))
        ctxdrvdata_num_offset = self.ramdump.field_offset(
            'struct msm_iommu_ctx_drvdata', 'num')
        num = self.ramdump.read_u32(node + ctxdrvdata_num_offset)
        if ctx_drvdata_name_ptr != 0:
            name = self.ramdump.read_cstring(ctx_drvdata_name_ptr, 100)
            ctx_list.append((num, name))

    def _iommu_domain_func(self, node, domain_list):
        domain_num = self.ramdump.read_u32(self.ramdump.sibling_field_addr(
            node, 'struct msm_iova_data', 'node', 'domain_num'))
        domain = self.ramdump.read_word(self.ramdump.sibling_field_addr(
            node, 'struct msm_iova_data', 'node', 'domain'))
        priv_ptr = self.ramdump.read_word(
            domain + self.ramdump.field_offset('struct iommu_domain', 'priv'))

        client_name_offset = self.ramdump.field_offset(
            'struct msm_iommu_priv', 'client_name')

        if client_name_offset is not None:
            client_name_ptr = self.ramdump.read_word(
                priv_ptr + self.ramdump.field_offset(
                    'struct msm_iommu_priv', 'client_name'))
            if client_name_ptr != 0:
                client_name = self.ramdump.read_cstring(client_name_ptr, 100)
            else:
                client_name = '(null)'
        else:
            client_name = 'unknown'

        list_attached_offset = self.ramdump.field_offset(
                'struct msm_iommu_priv', 'list_attached')

        if list_attached_offset is not None:
            list_attached = self.ramdump.read_word(priv_ptr + list_attached_offset)
        else:
            list_attached = None

        priv_pt_offset = self.ramdump.field_offset('struct msm_iommu_priv', 'pt')
        pgtable_offset = self.ramdump.field_offset('struct msm_iommu_pt', 'fl_table')
        redirect_offset = self.ramdump.field_offset('struct msm_iommu_pt', 'redirect')

        if priv_pt_offset is not None:
            pg_table = self.ramdump.read_word(
                priv_ptr + priv_pt_offset + pgtable_offset)
            redirect = self.ramdump.read_u32(
                priv_ptr + priv_pt_offset + redirect_offset)
        else:
            # On some builds we are unable to look up the offsets so hardcode
            # the offsets.
            pg_table = self.ramdump.read_word(priv_ptr + 0)
            redirect = self.ramdump.read_u32(priv_ptr + self.ramdump.sizeof('void *'))

            # Note: On some code bases we don't have this pg_table and redirect in the priv structure (see msm_iommu_sec.c). It only
            # contains list_attached. If this is the case we can detect that by checking whether
            # pg_table == redirect (prev == next pointers of the attached
            # list).
            if pg_table == redirect:
                # This is a secure domain. We don't have access to the page
                # tables.
                pg_table = 0
                redirect = None

        ctx_list = []
        if list_attached is not None and list_attached != 0:
            list_walker = llist.ListWalker(
                self.ramdump, list_attached,
                self.ramdump.field_offset('struct msm_iommu_ctx_drvdata', 'attached_elm'))
            list_walker.walk(list_attached, self._iommu_list_func, ctx_list)

        domain_list.append(
            Domain(domain_num, pg_table, redirect, ctx_list, client_name))