L4HQ - IA32 Architecture

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IA32 Architecture

Supported Kernels

The L4Ka::Pistachio kernel offers support for the IA32 architecture (486, Intel Pentium, Pentium II, and Pentium III, Pentium 4, VMWare Workstation 4.5 and the SIMICS simulator). See L4Ka.org for more information about L4Ka::Pistachio. The IA32 port of L4Ka::Pistachio is the reference architecture and therefore in the most complete state. It supports most features of the Version 4 API and has relatively well-tested SMP support.
Note, that all SMP support is still in an experimental stage. Multi-processors and APIC/IOAPIC support requires a system with ACPI. Older MP systems only providing Intel's MP structure are not supported and can therefore only be used in PIC and uniprocessor mode. L4Ka::Pistachio/ia32 was tested on the following multi-processor systems:

Dell PowerEdge 6400, 4way Pentium 3 Xeon 700MHz with 1MB L2 cache, 1.25GB RAM
Dual Pentium 3 800MHz, 256K L2 cache, 768MB RAM
IBM eServer xSeries 445, 8-way Intel Xeon 2.2 GHz (HT), 12 KB I-Cache, 8 KB D-Cache, 512/2048 KB L2/L3 U-cache, 2 GB RAM

IA32 Hardware References

Intel® IA32 Architecture Software Developer's Manual, Vol.1 Vol.2a Vol.2b Vol.3
Intel® IA32 Architecture Software Optimization Reference Manual

IA32 Related Websites

Intel® Developer Central

Building Pistachio on an IA32 processor

Kernel

The kernel can be built using GCC 2.95.2 and higher. However, we highly recommend using GCC 3.2 to make use of the far better code optimizations and thereby getting better performance results. Since most development systems are IA32 we assume that cross compilation is a non-issue. The kernel debugger can direct its I/O via the serial line or the keyboard/screen. Be sure to configure your kernel for the appropriate I/O device. The binary distribution includes the kernel configurations for the respective kernel binaries.

User-Level

The user-level applications are configured to use the serial port for I/O by default. To use screen I/O, run the configure script with the --without-comport command line option. If you want to use the serial port, you can choose a particular port by either specifying an index (0, 1, 2, or 3), or its physical device address (e.g. 0x3f8), with the --with-comport= command line option.

Booting Pistachio on an IA32 processor

The kernel can be booted using GRUB and L4Ka::KickStart; latter is part of the kernel distribution. GRUB requires a configuration file which contains all modules to be loaded. Besides the kernel image itself further modules can be loaded. The kernel requires at least sigma0 and the root task. Following an example menu.lst file:

title=L4Ka::Pistachio
kernel=/kickstart
module=/ia32-kernel
module=/sigma0
module=/roottask

GRUB supports network booting using the TFTP protocol. For more details refer to the corresponding documentations. A ready-to-run GRUB floppy image can be generated and downloaded from here.
After booting, GRUB starts L4Ka::KickStart which then configures the kernel configuration page using the boot-loader provided configuration information. Afterwards, L4Ka::Kickstart hands over control to the kernel which bootstraps sigma0, sigma1 (if available), and the root task.

Runtime Output

The kernel prints diagnostic information to the screen (if the kernel debugger is enabled). The information appears as "spinning" characters in the upper right corner, one row per processor. The character will change upon kernel events. The events, in reverse display order (right to left), are

idler invocation 
timer interrupt 
hardware interrupts 
end-of-timeslice 
cross-processor

If the kernel prints the error message "CPU does not support all features (XYZ) -- halting" then the processor does not support required features to operate the kernel. XYZ represents a feature mask, which is validated against the CPUID instruction. When the kernel is configured for verbose init, it will print cryptic strings representing the missing features (the cryptic strings correlate to features enumerated in the ia32 manuals). To solve the problem, configure the kernel to use an older generation processor.

Missing Features / Known Bugs

Lipc() not implemented
IPC() does not return local thread IDs on intra-address space IPC
Kernel-ptab synchronization has race on SMP systems
SMP support for pre-ACPI systems missing