XDB – Intel® System Debugger 2015
Overview Training
Robert Mueller-Albrecht, TCE, SSG DPD ECDL
Agenda
1) What is XDB?
2) Debugger startup and device/platform support
3) Debugger usage (Android* an Linux*)
4) System State Inspection
5) Instruction Trace
6) UEFI debug
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What is XDB? - Summary
Source level Debugger for System Software
Key Features
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Linux* and Windows* host
JTAG debug for Intel® Core™, Xeon® & Quark SoC-based platforms
EFI/UEFI Firmware, bootloader debug, Linux* OS awareness
UEFI debugging, optionally with Agent module
Dynamically loaded Linux kernel module debug
JTAG system debug with event tracing (SVEN)
Full CPU register description and bitfield editor
Access to page translation and descriptor tables
LBR, IPT On-Chip instruction trace support, SMP run control support
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Intel® System Debugger for the Internet of Things
The only complete system debug solution for the Intel based Internet of Things
JTAG based bootloader, OS and device driver debug
Agent based UEFI debug
In depth visualization of memory configuration, system state and register sets
Common debugger front-end for all debug protocols
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OpenOCD*
Dfx Abstraction Layer
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Example: Galileo,
Intel® Quark SoC X1000
Example: Bayley Bay,
Intel® Atom™ Processor E3800
Deep Insights into memory and system configuration
Fast issue resolution with low-level system debuggers
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Intel® System Debugger and Intel® Quark SoC (1)
Supported Devices:
Intel® ITP-XDP3
Go to https://designintools.intel.com/, select the Debug Tools product
category and add ITP-XDP BR3 to your cart.
TinCanTools* FLYSWATTER2
Go to http://www.tincantools.com/wiki/Compiling_OpenOCD
Olimex* ARM-USB-OCD-H
Go to https://www.olimex.com/Products/ARM/JTAG/ARM-USB-OCD-H/
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Intel® System Debugger and Intel® Quark SoC (2)
Recommended setup for debugging with
OpenOCD*
• Host System
• USB 2.0 male-male A-B cable
• JTAG Probe
• ARM-JTAG-20-10 Adapter
• JTAG Port
• Intel® Galileo Board
• Serial Cable to view boot process
• Power Supply
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Supported Formats & Software
Object File formats:
 ELF/DWARF from GCC/ICC Compilers
 PE/COFF+PDB from Microsoft Compilers
 Multiple simultaneous modules / mixed formats
Linux-specific Features:
 Auto-detect Kernel Module load/unload
 Kernel Data structure viewer
 Includes kernel threads, process list, process address space, and more.
EFI-specific Features:
 Load sources for PEI, DXE, and SMM modules (by address)
 Agent-based debugging without JTAG…
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Supported Target Connection Methods
The debugger can connect via multiple methods:
Dfx Abstraction Layer API
for current Intel® Atom™ Processor, Intel® Quark SoC, Intel® Core™ Processors, Intel® Xeon™ Processors
Connect via conventional JTAG using ITP-XDP3 probe
Can be used concurrently with other Intel® ITPII clients
TCI API for older Intel® Atom™ Processors
Connect via conventional JTAG using ITP-XDP3 probe or Macraigor* usb2Demon*
OpenOCD* API for Intel® Quark SoC
Connect via conventional JTAG using low-cost JTAG probe (e.g. Olimex*, Flyswatter*)
Agent-based UEFI Debugger
Debug of UEFI firmware over USB/Serial using a target-side agent
Deployable on production hardware (no JTAG port)
Debug SEC/PEI/DXE with burned-in agent, or soft-load agent for post-shell work
User experience is identical regardless of target access method
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Starting the Debugger
Step 1:
Open the folder where XDB was installed
Step 2:
Select a startup script and launch it,
“start_xdb_2015_products” or
“start_xdb_UEFI_agent” or
“start_xdb_legacy_products” or
“start_xdb_gdb_remote”
Step 3:
Connect to your target using the “Connect” button
(or Ctrl-R)
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Intel® System Debugger Launcher
integrated into Eclipse* and Wind River* Workbench*
1. Define which debugger start-up to launch under “Launcher Options …”
2. Launch Debugger
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Standard Debugger Features
Multiple Source
Files
Linux & EFI
Support
Syntax-highlights
Execution Trace
CPU Structures
Breakpoints
Program State
And more!
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Initial Startup & overview
Connect/Disconnect
Toolbars / Menus
Most functions available
from menus & buttons
Assembly Window
Console Window
Displays status messages
(keep it open!)
Command-driven
operation also possible
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Connecting To Targets
Step 1: Click the
connect icon
Step 2: Select your probe
Step 3: Select your target platform
Step 3a (optional): Enter advanced
connection parameters
Step 4: Connect!
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Target Run Control
Run Control
•Run/stop the CPU
•Step into, over, out
ASM step over
ASM step into
Run until caller
Step Over function call
Step program until next source line
Restart target
Halt execution
Resume Execution
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Multiple HW threads
The debugger can display how the multiple logical cores are used and
indicate
which logical core is used by the current code displayed.
You can select a logical core and continue debugging the SW running there.
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OS Debug – Getting Started
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Loading the symbols
Browse to find the
identical binary file as
Loaded on the target.
Download = download into
Target RAM. Do not tick this if
You will debug SW already
on the target
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How to find the sources
The debugger will try to find the source file
which matches the current instruction pointer.
If it cannot find the file it will ask you to do a
manual search.
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Select source files to view
With the ‘Source Files’ icon you can open a
window which contains the source tree as found
in the binary file loaded in the debugger.
Just double click on any of the source
file names to open the file in the source window.
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Evaluate symbols
Hover the cursor over a variable and the debugger will show you its value
Highlight a variable and use the ‘right mouse click’ – additional options are now available
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Local variables
Local variable window will
display all variables which
are accessible from within
current scope
The example above shows part of the ‘rq’ structure
In expression field indicate that this is a compound element and that it has been
Expanded ( > for not expanded)
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How did I reach the current location?
Source file:
line number
Current file
Function tree – bottom up
Only address presented when no debug information available
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Create a breakpoint
Minimum - code location is required.
Hard option allows you to set a breakpoint
even if the memory location is not
accessible
For Watchpoints the location,
access type and length are important
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Debugging loadable modules
There is a Linux kernel module [xdbntf] provided with the debugger which you can
build and install – you then can load & debug Linux kernel modules and device drivers
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Inspecting Android* & Linux* Kernel State
View all kernel thread with process id, current state, active flags, launch arguments
and call tree dependency.
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What happened?
Inspecting System State
XDB presents state in a “Human Readable” format
Relationships: “show the nesting of structure members”
High-level decode: “show the names of bits in a register”
Context: “show the documentation for a register”
Program State:
Memory contents -> “Memory Window”
Program State -> “Locals Window / Eval Window”
CPU State:
General and Extended Registers
Page Tables
IA CPU data structures (GDT, IDT, LDT)
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Overview of State Windows:
Callstack & HW Threads
Program Variables
Memory & Registers
Page Tables
Linux Kernel State
PCI Topology & Devices
Processor Structures
Execution Trace
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Program State:
Callstack Window
Show call stack for the currently
selected hardware thread
“Locals” Window
Program state for the
currently selected callstack
frame
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CPU State: Register Windows
GP Registers
CPU Registers
Model-Specific Registers
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CPU State: Detailed Register View
Bit-level Breakdown
Text Documentation
Set/Restore Values
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What about paging?
Double click on a page table/directory
entry and You will have the ability to
modify the attribute bits with the
bit field editor
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Virtual -> physical address mapping
Select an address and press Translate to find the address mapping.
When you press OK the page directory/table involved will be shown in the Paging window
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Execution Trace
XDB supports execution trace via:
Intel Processor Trace (Intel PT)
Last-Branch Record (LBR)
Trace data is presented as C source
code, view is integrated with other
source debug features
User is not concerned with underlying mechanism, it
“just works”
XDB Execution
Trace Viewer
Trace
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Execution Trace GUI Overview
Execution Trace GUI is fully integrated with source
debug, user can view trace data simultaneously with
source, ASM , callstack…
Source window
ASM window
Execution Trace
history
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Execution Trace Features
Expand source lines
to reveal assembly
Jump to this line’s
source file or
instruction
Keep source and/or
assembler window
in-sync with trace
window
Clear trace buffers
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Execution Trace Features (continued)
Colors indicating how recently
the instruction/line was executed
Intuitive
following of
execution flow
“+” indicates
multiple hits
Coloring can be configured in Options -> GUI Preferences
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PCI Scan Tool Technology Preview
Scan for devices, display device-specific registers:
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SVEN SoC Trace – low overhead technology for
static instrumentation of key SoC components
User
Event
Recorder
V
Device
Kernel
Intrumented Software Modules of
Devices & Systems
JTAG Device
• Event tracing with JTAG
• Smart breakpoints
• Interrupt execution on key events
• Visualize, Analyze and
Debug system event traces
• Command line interface
• Graphical interface
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SVEN Event:
SVEN - A Stethoscope for your System System & SoC trace through JTAG
Trace Visualization
 Advanced navigation, search & filter
 Graphical and textual event display
 User controlled trace line grouping
Smart Event Triggers
 Live JTAG system debug with event tracing
 Smart breakpoints that interrupt execution on trace event calls
 Set smart breakpoints for in-depth analysis
• Timeline view
For example:
• Search & Filter
 Break on any event from the USB driver
• Smart Event Trigger
definition
 Break on any Debug String that starts with “ERROR”
 Break if register X is accessed
 Break if register X bits [7-9] have value 0b101
Enhance system stability through powerful JTAG & event tracing
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UEFI Debug – Getting Started
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EFI BIOS Support
General EFI Features:
Active Mode (agent-based):
 Source-level debug in any phase of EFI,
from reset to OS boot
 Receive notifications from agent as
modules are loaded/unloaded
 Load symbols for all or selected modules
 Break at init of a named module,
regardless of load position
 Simultaneous debug of MSVC and GCCbuilt modules
Passive mode (interrogation-based):
 Requires debug agent
“SourceLevelDebugPkg” in EDKII
 Inspect target memory to locate
modules, load symbols
 Can be used on production BIOS
 Requires JTAG
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Stepping into BIOS code…
Before we can load symbols/source for EFI we need to be in protected mode
Using the Assembly-level Run Control features you can step from the reset
vector to the jump to protected mode:
You can also use the context menu in the ASM window:
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Loading Symbols for EFI BIOS
Once in protected mode we can use an XDB function to load symbols for EFI:
“loadthis” command
 Key to EFI debug: searches memory for a relocatable EFI module, uses module
metadata to locate debug symbols & sources
 Works in all phases of EFI (SEC, PEI, DXE)
 Searches from the current IP or from the a supplied address
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Debugging in SEC with sources:
Once XDB has symbols loaded it can locate source code for the current instruction point.
Both Source and ASM-level run control is now possible:
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Setting a Breakpoint in Source Code
Using the “Source Files” window: find and open a specific file
Using the context menu: set a breakpoint on a source line
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Run to your Breakpoint!
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Summary
XDB – Intel® System Debugger is
• Intel’s system software debug solution for
UEFI BIOS, firmware, bootloader, OS and device driver debug.
• It supports JTAG via ITP-XDP3
• It supports UEFI BIOS debug via EDKII debug agent and JTAG
• It is available as part of Intel System Studio in public and NDA versions
Find out more at http://intel.ly/system-studio
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COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT.
Software and workloads used in performance tests may have been optimized for performance only on Intel microprocessors.
Performance tests, such as SYSmark and MobileMark, are measured using specific computer systems, components, software,
operations and functions. Any change to any of those factors may cause the results to vary. You should consult other
information and performance tests to assist you in fully evaluating your contemplated purchases, including the performance of
that product when combined with other products.
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trademarks of Intel Corporation in the U.S. and other countries.
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Intel’s compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel
microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the
availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent
optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture
are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the
specific instruction sets covered by this notice.
Notice revision #20110804
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10/25/2014