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  2. Technische Fakultät
  3. Department Informatik
Friedrich-Alexander-Universität Lehrstuhl für Informatik 4 (Systemsoftware)
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      • Aufgabe 0: C++ Streams
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                      Aufgabe 2: Unterbrechungen

                      Namespaces | Classes | Enumerations | Functions | Constants
                      Core Namespace Reference

                      Implements an abstraction for CPU internals. More...

                      Namespaces

                      namespace  Interrupt
                       Exception and Interrupt control.
                       

                      Classes

                      class  CR
                       Access to the Control Register. More...
                       
                      class  MSR
                       Access to the Model-Specific Register (MSR) More...
                       

                      Enumerations

                      enum  CR0 : uintptr_t {
                        CR0_PE = 1U << 0 ,
                        CR0_MP = 1U << 1 ,
                        CR0_EM = 1U << 2 ,
                        CR0_TS = 1U << 3 ,
                        CR0_ET = 1U << 4 ,
                        CR0_NE = 1U << 5 ,
                        CR0_WP = 1U << 16 ,
                        CR0_AM = 1U << 18 ,
                        CR0_NW = 1U << 29 ,
                        CR0_CD = 1U << 30 ,
                        CR0_PG = 1U << 31
                      }
                       Control Register 0. More...
                       
                      enum  CR4 : uintptr_t {
                        CR4_VME = 1U << 0 ,
                        CR4_PVI = 1U << 1 ,
                        CR4_TSD = 1U << 2 ,
                        CR4_DE = 1U << 3 ,
                        CR4_PSE = 1U << 4 ,
                        CR4_PAE = 1U << 5 ,
                        CR4_MCE = 1U << 6 ,
                        CR4_PGE = 1U << 7 ,
                        CR4_PCE = 1U << 8 ,
                        CR4_OSFXSR = 1U << 9 ,
                        CR4_OSXMMEXCPT = 1U << 10 ,
                        CR4_UMIP = 1U << 11 ,
                        CR4_VMXE = 1U << 13 ,
                        CR4_SMXE = 1U << 14 ,
                        CR4_FSGSBASE = 1U << 16 ,
                        CR4_PCIDE = 1U << 17 ,
                        CR4_OSXSAVE = 1U << 18 ,
                        CR4_SMEP = 1U << 20 ,
                        CR4_SMAP = 1U << 21 ,
                        CR4_PKE = 1U << 22
                      }
                       Control Register 4. More...
                       
                      enum  MSRs : uint32_t {
                        MSR_PLATFORM_INFO = 0xceU ,
                        MSR_TSC_DEADLINE = 0x6e0U ,
                        MSR_EFER = 0xC0000080U ,
                        MSR_STAR = 0xC0000081U ,
                        MSR_LSTAR = 0xC0000082U ,
                        MSR_SFMASK = 0xC0000084U ,
                        MSR_FS_BASE = 0xC0000100U ,
                        MSR_GS_BASE = 0xC0000101U ,
                        MSR_SHADOW_GS_BASE = 0xC0000102U
                      }
                       Model-Specific Register Identifiers. More...
                       
                      enum  MSR_EFER : uintptr_t {
                        MSR_EFER_SCE = 1U << 0 ,
                        MSR_EFER_LME = 1U << 8 ,
                        MSR_EFER_LMA = 1U << 10 ,
                        MSR_EFER_NXE = 1U << 11 ,
                        MSR_EFER_SVME = 1U << 12 ,
                        MSR_EFER_LMSLE = 1U << 13 ,
                        MSR_EFER_FFXSR = 1U << 14 ,
                        MSR_EFER_TCE = 1U << 15
                      }
                       

                      Functions

                      void init ()
                       Initialize this CPU core. More...
                       
                      void exit ()
                       Deinitialize this CPU core. More...
                       
                      unsigned getID ()
                       Get the ID of the current CPU core using LAPIC::getID() with an internal lookup table. More...
                       
                      unsigned count ()
                       Get number of available CPU cores. More...
                       
                      unsigned countOnline ()
                       Get number of successfully started (and currently active) CPU cores. More...
                       
                      bool isOnline (uint8_t core_id)
                       Check if CPU core is currently active. More...
                       
                      void pause ()
                       Gives the core a hint that it is executing a spinloop and should sleep "shortly". More...
                       
                      void idle ()
                       Halt the CPU core until the next interrupt. More...
                       
                      void die ()
                       Permanently halts the core. More...
                       

                      Constants

                      const unsigned MAX = 8
                       Maximum number of supported CPUs.
                       

                      Detailed Description

                      Implements an abstraction for CPU internals.

                      These internals include functions to allow or deny interrupts, access control registers.

                      Enumeration Type Documentation

                      enum Core::CR0 : uintptr_t

                      Control Register 0.

                      See also
                      ISDMv3, 2.5 Control Registers
                      Enumerator
                      CR0_PE 

                      Protected Mode enabled.

                      CR0_MP 

                      Monitor co-processor.

                      CR0_EM 

                      Emulation (no x87 floating-point unit present)

                      CR0_TS 

                      Task switched.

                      CR0_ET 

                      Extension type.

                      CR0_NE 

                      Numeric error.

                      CR0_WP 

                      Write protect.

                      CR0_AM 

                      Alignment mask.

                      CR0_NW 

                      Not-write through caching.

                      CR0_CD 

                      Cache disable.

                      CR0_PG 

                      Paging.

                      enum Core::CR4 : uintptr_t

                      Control Register 4.

                      See also
                      ISDMv3, 2.5 Control Registers
                      Enumerator
                      CR4_VME 

                      Virtual 8086 Mode Extensions.

                      CR4_PVI 

                      Protected-mode Virtual Interrupts.

                      CR4_TSD 

                      Time Stamp Disable.

                      CR4_DE 

                      Debugging Extensions.

                      CR4_PSE 

                      Page Size Extension.

                      CR4_PAE 

                      Physical Address Extension.

                      CR4_MCE 

                      Machine Check Exception.

                      CR4_PGE 

                      Page Global Enabled.

                      CR4_PCE 

                      Performance-Monitoring Counter enable.

                      CR4_OSFXSR 

                      Operating system support for FXSAVE and FXRSTOR instructions.

                      CR4_OSXMMEXCPT 

                      Operating System Support for Unmasked SIMD Floating-Point Exceptions.

                      CR4_UMIP 

                      User-Mode Instruction Prevention.

                      CR4_VMXE 

                      Virtual Machine Extensions Enable.

                      CR4_SMXE 

                      Safer Mode Extensions Enable.

                      CR4_FSGSBASE 

                      Enables the instructions RDFSBASE, RDGSBASE, WRFSBASE, and WRGSBASE.

                      CR4_PCIDE 

                      PCID Enable.

                      CR4_OSXSAVE 

                      XSAVE and Processor Extended States Enable.

                      CR4_SMEP 

                      Supervisor Mode Execution Protection Enable.

                      CR4_SMAP 

                      Supervisor Mode Access Prevention Enable.

                      CR4_PKE 

                      Protection Key Enable.

                      enum Core::MSRs : uint32_t

                      Model-Specific Register Identifiers.

                      Selection of useful identifiers.

                      See also
                      ISDMv4
                      Enumerator
                      MSR_PLATFORM_INFO 

                      Platform information including bus frequency (Intel)

                      MSR_TSC_DEADLINE 

                      Register for LAPIC::Timer Deadline mode.

                      MSR_EFER 

                      Extended Feature Enable Register,.

                      See also
                      Core::MSR_EFER
                      MSR_STAR 

                      eip (protected mode), ring 0 and 3 segment bases

                      MSR_LSTAR 

                      rip (long mode)

                      MSR_SFMASK 

                      lower 32 bit: flag mask, if bit is set corresponding rflag is cleared through syscall

                      MSR_GS_BASE 

                      Current GS base pointer.

                      MSR_SHADOW_GS_BASE 

                      Usually called MSR_KERNEL_GS_BASE but this is misleading.

                      enum Core::MSR_EFER : uintptr_t
                      Enumerator
                      MSR_EFER_SCE 

                      System Call Extensions.

                      MSR_EFER_LME 

                      Long mode enable.

                      MSR_EFER_LMA 

                      Long mode active.

                      MSR_EFER_NXE 

                      No-Execute Enable.

                      MSR_EFER_SVME 

                      Secure Virtual Machine Enable.

                      MSR_EFER_LMSLE 

                      Long Mode Segment Limit Enable.

                      MSR_EFER_FFXSR 

                      Fast FXSAVE/FXRSTOR instruction.

                      MSR_EFER_TCE 

                      Translation Cache Extension.

                      Function Documentation

                      void Core::init ( )

                      Initialize this CPU core.

                      Mark this core as online and setup the cores LAPIC by assigning it a unique logical APIC ID

                      Note
                      Should only be called from kernel_init() during startup.
                      void Core::exit ( )

                      Deinitialize this CPU core.

                      Mark this Core as offline

                      Note
                      Should only be called from kernel_init() after returning from main() or main_ap().
                      unsigned Core::getID ( )

                      Get the ID of the current CPU core using LAPIC::getID() with an internal lookup table.

                      Returns
                      ID of current Core (a number between 0 and Core::MAX)
                      unsigned Core::count ( )

                      Get number of available CPU cores.

                      Returns
                      total number of cores
                      unsigned Core::countOnline ( )

                      Get number of successfully started (and currently active) CPU cores.

                      Returns
                      total number of online cores
                      bool Core::isOnline ( uint8_t  core_id)

                      Check if CPU core is currently active.

                      Parameters
                      core_idID of the CPU core
                      Returns
                      true if successfully started and is currently active
                      void Core::pause ( )
                      inline

                      Gives the core a hint that it is executing a spinloop and should sleep "shortly".

                      Improves the over-all performance when executing a spinloop by waiting a short moment reduce the load on the memory.

                      See also
                      ISDMv2, Chapter 4. PAUSE - Spin Loop Hint
                      void Core::idle ( )
                      inline

                      Halt the CPU core until the next interrupt.

                      Halts the current CPU core such that it will wake up on the next interrupt. Internally, this function first enables the interrupts via sti and then halts the core using hlt. Halted cores can only be woken by interrupts. The effect of sti is delayed by one instruction, making the sequence sti hlt atomic (if interrupts were disabled previously).

                      See also
                      ISDMv2, Chapter 4. STI - Set Interrupt Flag
                      ISDMv2, Chapter 3. HLT - Halt
                      void Core::die ( )
                      inline

                      Permanently halts the core.

                      Permanently halts the current CPU core. Internally, this function first disables the interrupts via cli and then halts the CPU core using hlt. As halted CPU cores can only be woken by interrupts, it is guaranteed that this core will be halted until the next reboot. The execution of die never returns. On multicore systems, only the executing CPU core will be halted permanently, other cores will continue execution.

                      See also
                      ISDMv2, Chapter 3. CLI - Clear Interrupt Flag
                      ISDMv2, Chapter 3. HLT - Halt
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