f2c49dd248
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)
186 lines
3.7 KiB
C
186 lines
3.7 KiB
C
/* $FreeBSD$ */
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/* From: NetBSD: asm.h,v 1.18 1997/11/03 04:22:06 ross Exp */
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/*
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* Copyright (c) 1991,1990,1989,1994,1995,1996 Carnegie Mellon University
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* All Rights Reserved.
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*
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* Permission to use, copy, modify and distribute this software and its
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* documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
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* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie Mellon
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* the rights to redistribute these changes.
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*/
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/*
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* Assembly coding style
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*
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* This file contains macros and register defines to
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* aid in writing more readable assembly code.
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* Some rules to make assembly code understandable by
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* a debugger are also noted.
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*/
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/*
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* Macro to make a local label name.
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*/
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#define LLABEL(name,num) L ## name ## num
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/*
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* MCOUNT
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*/
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#if !defined(GPROF) && !defined(PROF)
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#define MCOUNT /* nothing */
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#else
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#define MCOUNT \
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br.call.sptk.many b7=_mcount
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#endif
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/*
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* ENTRY
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* Declare a global leaf function.
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* A leaf function does not call other functions.
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*/
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#define ENTRY(_name_, _n_args_) \
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.global _name_; \
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.align 16; \
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.proc _name_; \
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_name_:; \
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.regstk _n_args_, 0, 0, 0 \
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MCOUNT
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#define ENTRY_NOPROFILE(_name_, _n_args_) \
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.global _name_; \
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.align 16; \
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.proc _name_; \
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_name_:; \
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.regstk _n_args_, 0, 0, 0
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/*
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* STATIC_ENTRY
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* Declare a local leaf function.
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*/
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#define STATIC_ENTRY(_name_, _n_args_) \
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.align 16; \
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.proc _name_; \
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_name_:; \
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.regstk _n_args_, 0, 0, 0 \
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MCOUNT
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/*
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* XENTRY
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* Global alias for a leaf function, or alternate entry point
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*/
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#define XENTRY(_name_) \
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.globl _name_; \
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_name_:
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/*
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* STATIC_XENTRY
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* Local alias for a leaf function, or alternate entry point
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*/
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#define STATIC_XENTRY(_name_) \
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_name_:
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/*
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* END
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* Function delimiter
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*/
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#define END(_name_) \
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.endp _name_
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/*
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* EXPORT
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* Export a symbol
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*/
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#define EXPORT(_name_) \
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.global _name_; \
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_name_:
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/*
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* IMPORT
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* Make an external name visible, typecheck the size
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*/
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#define IMPORT(_name_, _size_) \
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/* .extern _name_,_size_ */
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/*
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* ABS
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* Define an absolute symbol
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*/
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#define ABS(_name_, _value_) \
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.globl _name_; \
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_name_ = _value_
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/*
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* BSS
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* Allocate un-initialized space for a global symbol
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*/
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#define BSS(_name_,_numbytes_) \
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.comm _name_,_numbytes_
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/*
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* MSG
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* Allocate space for a message (a read-only ascii string)
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*/
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#define ASCIZ .asciz
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#define MSG(msg,reg,label) \
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addl reg,@ltoff(label),gp;; \
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ld8 reg=[reg];; \
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.data; \
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label: ASCIZ msg; \
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.text;
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/*
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* System call glue.
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*/
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#define SYSCALLNUM(name) SYS_ ## name
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#define CALLSYS_NOERROR(name) \
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{ .mmi ; \
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alloc r9 = ar.pfs, 0, 0, 8, 0 ; \
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mov r31 = ar.k5 ; \
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mov r10 = b0 ;; } \
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{ .mib ; \
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mov r8 = SYSCALLNUM(name) ; \
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mov b7 = r31 ; \
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br.call.sptk b0 = b7 ;; }
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/*
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* WEAK_ALIAS: create a weak alias (ELF only).
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*/
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#define WEAK_ALIAS(alias,sym) \
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.weak alias; \
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alias = sym
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/*
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* ID tag macros
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*/
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#if !defined(lint) && !defined(STRIP_FBSDID)
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#define __FBSDID(s) .ident s
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#else
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#define __FBSDID(s) /* nothing */
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#endif /* not lint and not STRIP_FBSDID */
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