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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)
50 lines
2.0 KiB
C
50 lines
2.0 KiB
C
/*-
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* Copyright (c) 1999 Marcel Moolenaar
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer
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* in this position and unchanged.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _MACHINE_UCONTEXT_H_
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#define _MACHINE_UCONTEXT_H_
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#include <machine/_regset.h>
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typedef struct __mcontext {
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uint64_t mc_flags;
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#define IA64_MC_FLAGS_SCRATCH_VALID 1
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#define IA64_MC_FLAGS_HIGHFP_VALID 2
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uint64_t _reserved_;
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struct _special mc_special;
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struct _callee_saved mc_preserved;
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struct _callee_saved_fp mc_preserved_fp;
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struct _caller_saved mc_scratch;
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struct _caller_saved_fp mc_scratch_fp;
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struct _high_fp mc_high_fp;
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} mcontext_t;
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#endif /* !_MACHINE_UCONTEXT_H_ */
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