freebsd-skq/sys/conf/options.ia64
Marcel Moolenaar f2c49dd248 Revamp of the syscall path, exception and context handling. The
prime objectives are:
o  Implement a syscall path based on the epc inststruction (see
   sys/ia64/ia64/syscall.s).
o  Revisit the places were we need to save and restore registers
   and define those contexts in terms of the register sets (see
   sys/ia64/include/_regset.h).

Secundairy objectives:
o  Remove the requirement to use contigmalloc for kernel stacks.
o  Better handling of the high FP registers for SMP systems.
o  Switch to the new cpu_switch() and cpu_throw() semantics.
o  Add a good unwinder to reconstruct contexts for the rare
   cases we need to (see sys/contrib/ia64/libuwx)

Many files are affected by this change. Functionally it boils
down to:
o  The EPC syscall doesn't preserve registers it does not need
   to preserve and places the arguments differently on the stack.
   This affects libc and truss.
o  The address of the kernel page directory (kptdir) had to
   be unstaticized for use by the nested TLB fault handler.
   The name has been changed to ia64_kptdir to avoid conflicts.
   The renaming affects libkvm.
o  The trapframe only contains the special registers and the
   scratch registers. For syscalls using the EPC syscall path
   no scratch registers are saved. This affects all places where
   the trapframe is accessed. Most notably the unaligned access
   handler, the signal delivery code and the debugger.
o  Context switching only partly saves the special registers
   and the preserved registers. This affects cpu_switch() and
   triggered the move to the new semantics, which additionally
   affects cpu_throw().
o  The high FP registers are either in the PCB or on some
   CPU. context switching for them is done lazily. This affects
   trap().
o  The mcontext has room for all registers, but not all of them
   have to be defined in all cases. This mostly affects signal
   delivery code now. The *context syscalls are as of yet still
   unimplemented.

Many details went into the removal of the requirement to use
contigmalloc for kernel stacks. The details are mostly CPU
specific and limited to exception_save() and exception_restore().
The few places where we create, destroy or switch stacks were
mostly simplified by not having to construct physical addresses
and additionally saving the virtual addresses for later use.

Besides more efficient context saving and restoring, which of
course yields a noticable speedup, this also fixes the dreaded
SMP bootup problem as a side-effect. The details of which are
still not fully understood.

This change includes all the necessary backward compatibility
code to have it handle older userland binaries that use the
break instruction for syscalls. Support for break-based syscalls
has been pessimized in favor of a clean implementation. Due to
the overall better performance of the kernel, this will still
be notived as an improvement if it's noticed at all.

Approved by: re@ (jhb)
2003-05-16 21:26:42 +00:00

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# $FreeBSD$
# Options specific to the ia64 platform kernels
ITANIUM opt_global.h
ITANIUM2 opt_global.h
IA32 opt_global.h
PAGE_SIZE_4K opt_global.h
PAGE_SIZE_8K opt_global.h
PAGE_SIZE_16K opt_global.h
PPC_PROBE_CHIPSET opt_ppc.h
PPC_DEBUG opt_ppc.h
MAXCONS opt_syscons.h
SC_ALT_MOUSE_IMAGE opt_syscons.h
SC_CUT_SPACES2TABS opt_syscons.h
SC_CUT_SEPCHARS opt_syscons.h
SC_DEBUG_LEVEL opt_syscons.h
SC_DFLT_FONT opt_syscons.h
SC_DISABLE_DDBKEY opt_syscons.h
SC_DISABLE_REBOOT opt_syscons.h
SC_HISTORY_SIZE opt_syscons.h
SC_KERNEL_CONS_ATTR opt_syscons.h
SC_KERNEL_CONS_REV_ATTR opt_syscons.h
SC_MOUSE_CHAR opt_syscons.h
SC_NO_CUTPASTE opt_syscons.h
SC_NO_FONT_LOADING opt_syscons.h
SC_NO_HISTORY opt_syscons.h
SC_NO_SYSMOUSE opt_syscons.h
SC_NORM_ATTR opt_syscons.h
SC_NORM_REV_ATTR opt_syscons.h
SC_PIXEL_MODE opt_syscons.h
SC_RENDER_DEBUG opt_syscons.h
SC_TWOBUTTON_MOUSE opt_syscons.h
SC_NO_SUSPEND_VTYSWITCH opt_syscons.h
VGA_ALT_SEQACCESS opt_vga.h
VGA_DEBUG opt_vga.h
VGA_NO_FONT_LOADING opt_vga.h
VGA_NO_MODE_CHANGE opt_vga.h
VGA_SLOW_IOACCESS opt_vga.h
VGA_WIDTH90 opt_vga.h
PSM_HOOKRESUME opt_psm.h
PSM_RESETAFTERSUSPEND opt_psm.h
PSM_DEBUG opt_psm.h
# Atkbd options
ATKBD_DFLT_KEYMAP opt_atkbd.h
# Kbd options
KBD_DISABLE_KEYMAP_LOAD opt_kbd.h
KBD_INSTALL_CDEV opt_kbd.h
KBD_MAXRETRY opt_kbd.h
KBD_MAXWAIT opt_kbd.h
KBD_RESETDELAY opt_kbd.h
KBDIO_DEBUG opt_kbd.h
# Clock options
CLK_USE_I8254_CALIBRATION opt_clock.h
TIMER_FREQ opt_clock.h
# SKI emulator options
SKI opt_ski.h
SKI_ROOT_FILESYSTEM opt_ski.h
SSC_NSECT opt_ski.h
# Device options
DEV_SPLASH opt_splash.h
DEV_ACPI opt_acpi.h