7bc6e7456e
of the kernel address space already. Intel recommend this anyway, because using a non-4GB limit adds an additional clock cycle to address generation. We were able to install 4GB segments into the LDT, so any limits we imposed on %cs and %ds were academic anyway. More importantly, this allows us to make a page in the kernel readable to user applications, for holding things like the signal trampoline and other fun things. Move the user %cs/%ds segments from the LDT to the GDT. There was no good reason for them to be there anyway. The old LDT entries are still there but we can now relax the restriction that prevented users from emptying the default LDT entries. Putting user and kernel %cs and %ds together allows us to access the fast sysenter/sysexit/syscall/sysret instructions. syscall/sysret in particular require that the user/kernel segments be laid out this way. Reserve a slot specifically for NDIS while here. Create two user controllable slots in the GDT that are context switched with the (kernel) thread. This allows user applications to set two user privilige selectors to arbitary values. Create i386_set_fsbase(void *base) and friends. (get/set, fs/gs). For i386, %gs is used by tls and the thread libraries and this means that user processes no longer have to have the cost of having a custom LDT, and we will no longer to do a ldt switch when activating a kthread/ithread in the usual case any more. In other words, we can now set the base address for %fs and %gs to arbitary addresses without the pain of messing with ldt segments.
177 lines
5.4 KiB
C
177 lines
5.4 KiB
C
/*-
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* Copyright (c) Peter Wemm <peter@netplex.com.au>
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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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* 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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _MACHINE_PCPU_H_
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#define _MACHINE_PCPU_H_
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#ifndef _SYS_CDEFS_H_
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#error this file needs sys/cdefs.h as a prerequisite
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#endif
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#ifdef _KERNEL
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#include <machine/segments.h>
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#include <machine/tss.h>
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/*
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* The SMP parts are setup in pmap.c and locore.s for the BSP, and
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* mp_machdep.c sets up the data for the AP's to "see" when they awake.
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* The reason for doing it via a struct is so that an array of pointers
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* to each CPU's data can be set up for things like "check curproc on all
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* other processors"
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*/
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#define PCPU_MD_FIELDS \
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struct pcpu *pc_prvspace; /* Self-reference */ \
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struct pmap *pc_curpmap; \
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struct i386tss pc_common_tss; \
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struct segment_descriptor pc_common_tssd; \
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struct segment_descriptor *pc_tss_gdt; \
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struct segment_descriptor *pc_fsgs_gdt; \
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int pc_currentldt; \
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u_int pc_acpi_id; \
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u_int pc_apic_id
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#if defined(lint)
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extern struct pcpu *pcpup;
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#define PCPU_GET(member) (pcpup->pc_ ## member)
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#define PCPU_PTR(member) (&pcpup->pc_ ## member)
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#define PCPU_SET(member,value) (pcpup->pc_ ## member = (value))
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#elif defined(__GNUCLIKE_ASM) && defined(__GNUCLIKE___TYPEOF) \
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&& defined(__GNUCLIKE___OFFSETOF)
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/*
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* Evaluates to the byte offset of the per-cpu variable name.
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*/
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#define __pcpu_offset(name) \
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__offsetof(struct pcpu, name)
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/*
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* Evaluates to the type of the per-cpu variable name.
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*/
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#define __pcpu_type(name) \
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__typeof(((struct pcpu *)0)->name)
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/*
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* Evaluates to the address of the per-cpu variable name.
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*/
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#define __PCPU_PTR(name) __extension__ ({ \
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__pcpu_type(name) *__p; \
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\
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__asm __volatile("movl %%fs:%1,%0; addl %2,%0" \
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: "=r" (__p) \
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: "m" (*(struct pcpu *)(__pcpu_offset(pc_prvspace))), \
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"i" (__pcpu_offset(name))); \
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\
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__p; \
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})
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/*
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* Evaluates to the value of the per-cpu variable name.
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*/
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#define __PCPU_GET(name) __extension__ ({ \
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__pcpu_type(name) __result; \
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\
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if (sizeof(__result) == 1) { \
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u_char __b; \
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__asm __volatile("movb %%fs:%1,%0" \
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: "=r" (__b) \
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: "m" (*(u_char *)(__pcpu_offset(name)))); \
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__result = *(__pcpu_type(name) *)(void *)&__b; \
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} else if (sizeof(__result) == 2) { \
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u_short __w; \
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__asm __volatile("movw %%fs:%1,%0" \
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: "=r" (__w) \
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: "m" (*(u_short *)(__pcpu_offset(name)))); \
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__result = *(__pcpu_type(name) *)(void *)&__w; \
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} else if (sizeof(__result) == 4) { \
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u_int __i; \
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__asm __volatile("movl %%fs:%1,%0" \
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: "=r" (__i) \
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: "m" (*(u_int *)(__pcpu_offset(name)))); \
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__result = *(__pcpu_type(name) *)(void *)&__i; \
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} else { \
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__result = *__PCPU_PTR(name); \
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} \
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\
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__result; \
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})
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/*
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* Sets the value of the per-cpu variable name to value val.
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*/
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#define __PCPU_SET(name, val) { \
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__pcpu_type(name) __val = (val); \
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\
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if (sizeof(__val) == 1) { \
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u_char __b; \
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__b = *(u_char *)&__val; \
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__asm __volatile("movb %1,%%fs:%0" \
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: "=m" (*(u_char *)(__pcpu_offset(name))) \
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: "r" (__b)); \
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} else if (sizeof(__val) == 2) { \
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u_short __w; \
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__w = *(u_short *)&__val; \
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__asm __volatile("movw %1,%%fs:%0" \
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: "=m" (*(u_short *)(__pcpu_offset(name))) \
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: "r" (__w)); \
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} else if (sizeof(__val) == 4) { \
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u_int __i; \
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__i = *(u_int *)&__val; \
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__asm __volatile("movl %1,%%fs:%0" \
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: "=m" (*(u_int *)(__pcpu_offset(name))) \
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: "r" (__i)); \
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} else { \
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*__PCPU_PTR(name) = __val; \
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} \
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}
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#define PCPU_GET(member) __PCPU_GET(pc_ ## member)
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#define PCPU_PTR(member) __PCPU_PTR(pc_ ## member)
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#define PCPU_SET(member, val) __PCPU_SET(pc_ ## member, val)
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static __inline struct thread *
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__curthread(void)
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{
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struct thread *td;
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__asm __volatile("movl %%fs:0,%0" : "=r" (td));
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return (td);
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}
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#define curthread (__curthread())
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#else
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#error this file needs to be ported to your compiler
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#endif
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#endif /* _KERNEL */
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#endif /* ! _MACHINE_PCPU_H_ */
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