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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
        • Aufgabe 1: Ein-/Ausgabe
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                Aufgabe 1: Ein-/Ausgabe

                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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