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Profiling the ACPICA Namespace and Event Handing

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Profiling the ACPICA Namespace and Event Handing
September, 2019, SUSE Labs Conference 2019, Špindlerův

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Profiling the ACPICA Namespace and Event Handing

  1. 1. Profiling the ACPICA Namespace and Event Handing September, 2019, SUSE Labs Conference 2019, Špindlerův mlýn Joey Lee SUSE Labs Taipei jlee@suse.com
  2. 2. 2 Agenda • Components in ACPICA • ACPICA in Linux Kernel • Definition blocks and ACPI Namespace • The Fixed event and GPE handling • Q&A
  3. 3. 3 ACPICA • The ACPI Component Architecture (CA) is the core of Advanced Configuration and Power Interface (ACPI) subsystem in Linux kernel. • The ACPICA provides the fundamental ACPI services that are independent of any operating system. [1] • Mainly maintained by Intel ‒ https://github.com/acpica/acpica.git
  4. 4. 4 ACPICA (cont.) • ACPICA’s services include an AML parser/interpreter, ACPI namespace management, ACPI table management and event handling [1]. • The OS Services Layer (OSL) is a conversion layer between the OS-independent ACPICA to a particular host operating system. [1]
  5. 5. 5 ACPI Namespace and Event handing • ACPI Namespace ‒ A static tree structure reflects to AML definition blocks which is an abstract layer of hardware devices in platform. • ACPI Event handing ‒ ACPICA provides event mechanisms to define and to handle the dynamic behavior at runtime.
  6. 6. Components in ACPICA
  7. 7. 7 ACPICA components • ACPI fundamental: Namespace Management, Table Management, Event Handling, Resource Manager, Hardware Management, Utilities • AML interpreter: Dispatcher, Executer, Parser, Disassembler, Debugger • OS Services Layer (OSL) ‒ ACPICA implements OSL for user space of Unix, Linux, Windows and BSD. ‒ Linux Kernel’s ACPI subsystem maintains a OSL (drivers/acpi/osl.c) to adapt ACPICA.
  8. 8. 8 Kernel or Userland ACPICA Core Components ACPICA root Namespace AML Interpreter Tables node node Events OSL Parser Resources Hardware Utilities Disassembler Dispatcher Executer Debuggernode node node AcpiOs* Acpi*Acpi* Acpi* Acpi* Acpi* Acpi*
  9. 9. 9 ACPICA tools • iasl: ASL compiler / AML decompiler • Tools: acpidump, acpixtract, acpinames, acpiexec... • Tests: ASL grammar validation Test Suite (ASLTS), ASL test cases • Generate: generation tools, release tools
  10. 10. 10 ACPICA and Tools Components Namespace AML Interpreter Tables Events OSL Parser Resources Hardware Utilities Disassembler Dispatcher Executer Debugger Tools acpidump acpiexec Compiler TestsGenerate release linux msvc unix msvc9 efi acpixtract root node node node node node iasl osunix* oslinux* oswin* osbsd* efi* aslts Acpi*Acpi* AcpiOs*
  11. 11. ACPICA in Linux Kernel
  12. 12. 12 ACPI host and ACPICA • OSL in Linux Kernel: drivers/acpi/osl.c • ACPICA-to-host: All ACPICA-to-host interactions pass through the OSL via direct calls to the AcpiOs* interfaces from ACPICA. [1] • Host-to-ACPICA ‒ Synchronous: the host making direct calls to the various public Acpi* interfaces. [1] ‒ Asynchronous: The host calls ACPICA to install an appropriate handler at initialization time. This handler is then invoked by ACPICA whenever the requested event occurs. (handle fixed events or GPE) [1]
  13. 13. 13 OSL Services • Environmental: enable acpi mode • Memory Management: mm • Multitasking Support • Mutual Exclusion and Synchronization • Interrupt handling: IRQ • Address Spaces • Stream I/O: printk
  14. 14. 14 Platform Kernel ACPICA in Linux Kernel Firmware ACPI Tables RSDP XSDT Hardware ACPI ACPICA root bus driver device Namespace AML Interpreter Tables node node Event FADT DSDT SSDT2SSDT1 Resource Hardware mm OSL resource printkEFIIRQqueue PCI CPU Memory pm AcpiOs* Acpi* Acpi*
  15. 15. Definition blocks and ACPI Namespace
  16. 16. 16 ACPI Tables • Definition blocks tables ‒ AML (ACPI Machine Language) format ‒ DSDT (differentiated system description table), SSDT (secondary system description tables) • Data tables ‒ TDL (Table Definition Language) ‒ FADT, MADT, ECDT, SRAT, etc. - essentially any table other than a DSDT or SSDT. [2] • The iasl tool supports AML and TDL
  17. 17. 17 ACPI Namespace • The ACPI Namespace is a large data structure that is constructed and maintained by the ACPICA Subsystem component. [1] • Constructed primarily from the AML defined within an ACPI Differentiated System Description Table (DSDT), the namespace contains a hierarchy of named ACPI objects. [1] root Namespace node node
  18. 18. 18 Definition blocks, Namespace and ACPI devices Tables OSL EFI ACPI Tables RSDP XSDT FADT DSDT SSDT2SSDT1 root Namespace AML Interpreter node node bus driver device
  19. 19. 19 Definition blocks, Namespace and ACPI devices [1]Load
  20. 20. 20 Definition blocks, Namespace and ACPI devices [1]Load [2]
  21. 21. 21 Definition blocks, Namespace and ACPI devices [1]Load [2] [3] Parse
  22. 22. 22 Definition blocks, Namespace and ACPI devices [1]Load [2] [3] Parse [4] handle
  23. 23. 23 Definition blocks, Namespace and ACPI devices [1]Load [2] [3] Parse PCI CPU Memory Companion Companion Companion PCI CPU Memory [4] handle
  24. 24. 24 Namespace Initialization • Firmware puts definition blocks tables (DSDT and SSDT*) to memory. • Table Management component loads DSDT and SSDT. ‒ OSL helps to get RSDP for loading ACPI tables • Table Management component forwards DSDT/SSDT points to Namespace Management component. • Namespace Management component requests AML interpreter to parse tables. • Base on parsing result, Namespace Management component creates ACPI namespace.
  25. 25. 25 ACPICA Table to Namespace tables 2) AcpiTbLoadNamespace namespace 2.1.1) AcpiNsParseTable AcpiNsExecuteTable 3.1) AcpiNsInitOneObject 2.1) AcpiNsLoadTable 3) AcpiNsInitializeObjects 2.1.2) AcpiDsInitializeObjects 0) acpi_load_tables (AcpiLoadTables) Kernel drivers/acpi/bus.c events 1) AcpiEvInstallRegionHandlers dispatcher AcpiPsExecuteTable parser AcpiPsCreateScopeOp AcpiPsParseAml AcpiDsCreateWalkState AcpiDsInitAmlWalk AcpiDsScopeStackPush AcpiDsDeleteWalkState AcpiPsDeleteParseTree
  26. 26. 26 ACPICA Evaluate method/object namespace 1) AcpiNsValidateHandle 2) AcpiNsEvaluate 2.1) AcpiNsGetNode 2.4) AcpiNsCheckReturnValue 3) AcpiNsResolveReferences 0) acpi_evaluate_object (AcpiEvaluateObject) Kernel drivers/acpi/utils.c tables 2.2.1) AcpiTbCheckDsdtHeader dispatcher 2.2) AcpiPsExecuteMethod parser 2.2.3) AcpiPsUpdateParameterList 2.2.4) AcpiPsCreateScopeOp 2.2.7) AcpiPsParseAml 2.2.8) AcpiPsDeleteParseTree 2.2.9) AcpiPsUpdateParameterList 2.2.2) AcpiDsBeginMethodExecution 2.2.5) AcpiDsCreateWalkState 2.2.6) AcpiDsInitAmlWalk executer 2.3) AcpiExResolveNodeToValue
  27. 27. 27 The relation between layers
  28. 28. 28 The relation between layers
  29. 29. 29 The relation between layers
  30. 30. 30 The relation between layers
  31. 31. 31 The relation between layers
  32. 32. 32 The relation between layers
  33. 33. 33 The relation between layers
  34. 34. 34 The relation between layers
  35. 35. 35 The relation between layers
  36. 36. 36 Class diagram for ACPI Namespace
  37. 37. The Fixed event and GPE handling
  38. 38. 38 Event types in ACPICA • ACPI Fixed Events and General Purpose Events (GPEs) ‒ System Control Interrupts (SCIs) be generated • Event types in control method ‒ Notify events that are generated via the execution of the ASL Notify keyword in a control method. [1] ‒ Events that are caused by accesses to an address space or operation region during the execution of a control method. [1]
  39. 39. 39 System Control Interrupts (SCIs) • SCI ‒ IRQ9 on x86. (otherwise checking SCI_INT in FADT) • SCI handlers ‒ AcpiEvGpeXruptHandler, AcpiEvSciXruptHandler in ACPICA ‒ acpi_global_event_handler in Linux Kernel
  40. 40. 40 ACPI Events OSL root Namespace AML Interpreter node node bus driver device Hardware Event Platform Firmware ACPI Registers Hardware FADT PM1a IRQ GPE0 PM1b GPE1 Sleep Timer
  41. 41. 41 ACPI Events [1]Set
  42. 42. 42 ACPI Events [1]Set [2]SCI[2]SCI
  43. 43. 43 ACPI Events [1]Set [2]SCI[2]SCI [3] [3]Read Clear
  44. 44. 44 ACPI Events (Fixed Event) [1]Set [2]SCI[2]SCI [3] [3]Read Clear [4] Button
  45. 45. 45 ACPI Events (Fixed Event) [1]Set [2]SCI[2]SCI [3] [3]Read Clear [4] Button Input [5] input [5]Keycode
  46. 46. 46 ACPI Events (GPE) [1]Set [2]SCI[2]SCI [3] [3]Read Clear _Exx _Lxx _GPE
  47. 47. 47 ACPI Events (GPE) [1]Set [2]SCI[2]SCI [3] [3]Read Clear [4] _Exx _Lxx _GPE [5]
  48. 48. 48 ACPI Events (GPE) [1]Set [2]SCI[2]SCI [3] [3]Read Clear [4] _Exx _Lxx _GPE [5] [6]Access Address space [6] Notify
  49. 49. 49 ACPI Events (GPE) [1]Set [2]SCI[2]SCI [3] [3]Read Clear [4] _Exx _Lxx _GPE [5] [6]Access Address space [6] NotifyPCI CPU Memory PCI CPU Memory Interactive Interactive interactive
  50. 50. 50 Fixed Events • Fixed Events ‒ ACPI events that have a predefined meaning in the ACPI specification. e.g. power button, timer overflows. ‒ These events are handled directly by the OS handlers. [2] ‒ ACPI register: PM1 = PM1a | PM1b ‒ PM1x_STS.8: PWRBTN_STS ‒ PM1x_STS.9: SLPBTN_STS ‒ PM1x_STS.10: RTC_STS ….
  51. 51. 51 ACPICA Events (fixed) events 1) AcpiEvFixedEventDetect 1.3) AcpiEvFixedEventDispatch 2) AcpiEvGpeDetect 3) AcpiEvSciDispatch Kernel 0) acpi_ev_sci_xrupt_handler (AcpiEvSciXruptHandler) 1.1) AcpiHwRegisterRead Kernel/irq drivers/acpi 1.2) acpi_global_event_handler (AcpiGbl_GlobalEventHandler) bus.csysfs.c 1.3.1) acpi_device_fixed_event (AcpiGbl_FixedEventHandlers[Event].Handle) button.c 1.3.1.x) notify hardware
  52. 52. 52 GPEs • GPEs ‒ GPEs are ACPI events that are not predefined by the ACPI specification. ‒ These events are usually handled by evaluating control methods, which are objects in the namespace and can access system hardware. ‒ ACPI registers: GPE0_BLK, GPE1_BLK ‒ Control Methods: _GPE._Lxx, _GPE._Exx ‒ X86: reference GPE0_STS register in the Intel I/O Controller Hub (ICH) datasheet. ‒ watch -n 1 cat /sys/firmware/acpi/interrupts/gpe[012] [0123456789ABCDEF]
  53. 53. 53 ACPICA Events (GPE) events 1) AcpiEvFixedEventDetect 2) AcpiEvGpeDetect 2.1) AcpiEvDetectGpe 2.1.4) AcpiEvGpeDispatch AcpiEvQueueNotifyRequest 3) AcpiEvSciDispatch Kernel 0) acpi_ev_sci_xrupt_handler (AcpiEvSciXruptHandler) hardware AcpiPsExecuteMethod executer AcpiExResolveNodeToValue Kernel/irq drivers/acpi ec.csysfs.c osl.c 2.1.1) AcpiHwRead AcpiHwLowSetGpe AcpiHwClearGpe 2.1.2) acpi_global_event_handler (AcpiGbl_GlobalEventHandler) 2.1.3) acpi_ec_gpe_handler (GpeHandlerInfo->Address) Kernel/workqueue queue Namespace AcpiNsGetNode AcpiNsCheckReturnValue AcpiNsEvaluate parser AcpiEvAsynchExecuteGpeMethod acpi_os_execute
  54. 54. 54 Example: EC and _Qxx • A general-purpose event is raised from the GPE bit tied to an embedded controller, the embedded controller driver uses another naming convention defined by ACPI for the embedded controller driver to determine which control method to queue for execution. • The name of the control method to queue is always of the form _Qxx where xx is the number of the query acknowledged by the embedded controller.
  55. 55. 55 Class diagram for _Qxx event handling
  56. 56. 56 Summary • The interactive between two framework: Linux Kernel and ACPICA • ACPI Namespace: An abstract layer between hardware platform and OS • ACPI event handing: To define and handle the dynamic behavior between platform and OS
  57. 57. Q&A
  58. 58. 58 Reference • [1] ACPI Component Architecture User Guide and Programmer Reference Revision 6.2, May 31, 2017 • [2] Advanced Configuration and Power Interface (ACPI) Specification Version 6.3, January 2019
  59. 59. Thank you. 59 Feedback to jlee@suse.com
  60. 60. Corporate Headquarters Maxfeldstrasse 5 90409 Nuremberg Germany +49 911 740 53 0 (Worldwide) www.suse.com Join us on: www.opensuse.org 61
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