akaros/kern/arch/x86/Kconfig
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   1config X86
   2        select 64BIT
   3        def_bool y
   4
   5config X86_64
   6        def_bool 64BIT
   7
   8menu "x86 Options"
   9
  10config PCI_VERBOSE
  11        bool "Verbose PCI Output"
  12        default n
  13        help
  14          Will print out extra information related to PCI.
  15
  16config NOFASTCALL_FSBASE
  17        depends on X86_64
  18        bool "Disable fastcall to set FS base"
  19        default n
  20        help
  21          Disable the fast path syscall to set FS base.  If your hardware
  22          allows setting FS base from userspace, you can say y to disable the
  23          fastcall for a slight improvement for all syscalls.  If unsure, say
  24          n.
  25
  26endmenu
  27
  28menu "x86 Hacks"
  29
  30config LOUSY_LAPIC_TIMER
  31        bool "Lousy Local APIC Timer"
  32        default n
  33        help
  34          This turns our one-shot APIC timer into a periodic timer.  If your
  35          system seems to lock up until you hit the keyboard, say 'Y' here and
  36          report the results.
  37
  38          Qemu without KVM had issues firing a one-shot LAPIC timer (the timer
  39          IRQ would only go off when some other IRQ fired), but it worked with
  40          a periodic tick.  Since we aggressively disarm the timer, this config
  41          shouldn't be a performance hit.
  42
  43config NOMTRRS
  44        bool "Disable MTRRs"
  45        default y
  46        help
  47          Old debug option from when we were having issues with MTRRs.  If your
  48          machine won't boot, try turning this on.
  49
  50config KB_CORE0_ONLY
  51        bool "Keyboard from core0 only"
  52        default n
  53        help
  54          Say 'n' unless you are using a buggy x86 machine that can't handle
  55          polling the keyboard PIO from cores other than core 0.
  56
  57config X86_DISABLE_KEYBOARD
  58        bool "Disable Keyboard"
  59        default n
  60        help
  61          x86 machines with a legacy USB keyboard often implement the USB stack
  62          in SMM mode.  When doing anything with the keyboard, including
  63          polling the keyboard from the kernel monitor, SMM mode can
  64          dramatically interfere with other cores (like a 10-15x performance
  65          impact on some benchmarks).
  66
  67          Say 'y' if you have such a machine and do not need the keyboard.
  68
  69config ENABLE_LEGACY_USB
  70        bool "Enable Legacy USB"
  71        default n
  72        help
  73          Say 'y' if you want to use a USB keyboard.  Given that we do not have
  74          a USB stack, disabling legacy USB means USB keyboards will not work.
  75          We disable legacy USB by default, since our primary console
  76          communication is serial, and legacy USB support results in SMM
  77          interference that affects all cores.
  78
  79endmenu
  80