NetBSD-5.0.2/sys/arch/amd64/amd64/gdt.c
/* $NetBSD: gdt.c,v 1.19.8.1 2009/04/04 17:39:09 snj Exp $ */
/*-
* Copyright (c) 1996, 1997, 2009 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by John T. Kohl, by Charles M. Hannum, and by Andrew Doran.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Modified to deal with variable-length entries for NetBSD/x86_64 by
* fvdl@wasabisystems.com, may 2001
* XXX this file should be shared with the i386 code, the difference
* can be hidden in macros.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: gdt.c,v 1.19.8.1 2009/04/04 17:39:09 snj Exp $");
#include "opt_multiprocessor.h"
#include "opt_xen.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/mutex.h>
#include <sys/user.h>
#include <sys/cpu.h>
#include <uvm/uvm.h>
#include <machine/gdt.h>
#ifdef XEN
#include <xen/hypervisor.h>
#endif
int gdt_size; /* size of GDT in bytes */
int gdt_dyncount; /* number of dyn. allocated GDT entries in use */
int gdt_dynavail;
int gdt_next; /* next available slot for sweeping */
int gdt_free; /* next free slot; terminated with GNULL_SEL */
void gdt_init(void);
void gdt_grow(void);
int gdt_get_slot(void);
void gdt_put_slot(int);
void
set_mem_gdt(struct mem_segment_descriptor *sd, void *base, size_t limit,
int type, int dpl, int gran, int def32, int is64)
{
#if 0
CPU_INFO_ITERATOR cii;
struct cpu_info *ci;
int off;
#endif
set_mem_segment(sd, base, limit, type, dpl, gran, def32, is64);
#if 0
off = (char *)sd - gdtstore;
for (CPU_INFO_FOREACH(cii, ci)) {
if (ci->ci_gdt != NULL)
*(struct mem_segment_descriptor *)(ci->ci_gdt + off) =
*sd;
}
#endif
}
void
set_sys_gdt(struct sys_segment_descriptor *sd, void *base, size_t limit,
int type, int dpl, int gran)
{
#if 0
CPU_INFO_ITERATOR cii;
struct cpu_info *ci;
int off;
#endif
set_sys_segment(sd, base, limit, type, dpl, gran);
#if 0
off = (char *)sd - gdtstore;
for (CPU_INFO_FOREACH(cii, ci)) {
if (ci->ci_gdt != NULL)
*(struct sys_segment_descriptor *)(ci->ci_gdt + off) =
*sd;
}
#endif
}
/*
* Initialize the GDT.
*/
void
gdt_init(void)
{
char *old_gdt;
struct vm_page *pg;
vaddr_t va;
struct cpu_info *ci = &cpu_info_primary;
gdt_size = MINGDTSIZ;
gdt_dyncount = 0;
gdt_next = 0;
gdt_free = GNULL_SEL;
gdt_dynavail =
(gdt_size - DYNSEL_START) / sizeof (struct sys_segment_descriptor);
old_gdt = gdtstore;
gdtstore = (char *)uvm_km_alloc(kernel_map, MAXGDTSIZ, 0,
UVM_KMF_VAONLY);
for (va = (vaddr_t)gdtstore; va < (vaddr_t)gdtstore + MINGDTSIZ;
va += PAGE_SIZE) {
pg = uvm_pagealloc(NULL, 0, NULL, UVM_PGA_ZERO);
if (pg == NULL) {
panic("gdt_init: no pages");
}
pmap_kenter_pa(va, VM_PAGE_TO_PHYS(pg),
VM_PROT_READ | VM_PROT_WRITE);
}
pmap_update(pmap_kernel());
memcpy(gdtstore, old_gdt, DYNSEL_START);
ci->ci_gdt = (void *)gdtstore;
#ifndef XEN
set_sys_segment(GDT_ADDR_SYS(gdtstore, GLDT_SEL), ldtstore,
LDT_SIZE - 1, SDT_SYSLDT, SEL_KPL, 0);
#endif
gdt_init_cpu(ci);
}
/*
* Allocate shadow GDT for a slave CPU.
*/
void
gdt_alloc_cpu(struct cpu_info *ci)
{
#if 0
ci->ci_gdt = (void *)uvm_km_valloc(kernel_map, MAXGDTSIZ);
uvm_map_pageable(kernel_map, (vaddr_t)ci->ci_gdt,
(vaddr_t)ci->ci_gdt + MINGDTSIZ, false, false);
memset(ci->ci_gdt, 0, MINGDTSIZ);
memcpy(ci->ci_gdt, gdtstore,
DYNSEL_START + gdt_dyncount * sizeof(struct sys_segment_descriptor));
#else
ci->ci_gdt = (void *)gdtstore;
#endif
}
/*
* Load appropriate gdt descriptor; we better be running on *ci
* (for the most part, this is how a CPU knows who it is).
*/
void
gdt_init_cpu(struct cpu_info *ci)
{
struct region_descriptor region;
#ifndef XEN
setregion(®ion, ci->ci_gdt, (uint16_t)(MAXGDTSIZ - 1));
#else
/* Enter only allocated frames */
setregion(®ion, ci->ci_gdt, (uint16_t)(gdt_size - 1));
#endif
lgdt(®ion);
}
#ifdef MULTIPROCESSOR
void
gdt_reload_cpu(struct cpu_info *ci)
{
struct region_descriptor region;
#ifndef XEN
setregion(®ion, ci->ci_gdt, MAXGDTSIZ - 1);
#else
/* Enter only allocated frames */
setregion(®ion, ci->ci_gdt, gdt_size - 1);
#endif
lgdt(®ion);
}
#endif
/*
* Grow or shrink the GDT.
*/
void
gdt_grow(void)
{
size_t old_len, new_len;
struct vm_page *pg;
vaddr_t va;
old_len = gdt_size;
gdt_size <<= 1;
new_len = old_len << 1;
gdt_dynavail =
(gdt_size - DYNSEL_START) / sizeof (struct sys_segment_descriptor);
for (va = (vaddr_t)gdtstore + old_len; va < (vaddr_t)gdtstore + new_len;
va += PAGE_SIZE) {
while ((pg = uvm_pagealloc(NULL, 0, NULL, UVM_PGA_ZERO)) ==
NULL) {
uvm_wait("gdt_grow");
}
pmap_kenter_pa(va, VM_PAGE_TO_PHYS(pg),
VM_PROT_READ | VM_PROT_WRITE);
}
pmap_update(pmap_kernel());
}
/*
* Allocate a GDT slot as follows:
* 1) If there are entries on the free list, use those.
* 2) If there are fewer than gdt_dynavail entries in use, there are free slots
* near the end that we can sweep through.
* 3) As a last resort, we increase the size of the GDT, and sweep through
* the new slots.
*/
int
gdt_get_slot(void)
{
int slot;
struct sys_segment_descriptor *gdt;
gdt = (struct sys_segment_descriptor *)&gdtstore[DYNSEL_START];
KASSERT(mutex_owned(&cpu_lock));
if (gdt_free != GNULL_SEL) {
slot = gdt_free;
gdt_free = gdt[slot].sd_xx3; /* XXXfvdl res. field abuse */
} else {
#ifdef DIAGNOSTIC
if (gdt_next != gdt_dyncount)
panic("gdt_get_slot botch 1");
#endif
if (gdt_next >= gdt_dynavail) {
#ifdef DIAGNOSTIC
if (gdt_size >= MAXGDTSIZ)
panic("gdt_get_slot botch 2");
#endif
gdt_grow();
}
slot = gdt_next++;
}
gdt_dyncount++;
return (slot);
}
/*
* Deallocate a GDT slot, putting it on the free list.
*/
void
gdt_put_slot(int slot)
{
struct sys_segment_descriptor *gdt;
KASSERT(mutex_owned(&cpu_lock));
gdt = (struct sys_segment_descriptor *)&gdtstore[DYNSEL_START];
gdt_dyncount--;
gdt[slot].sd_type = SDT_SYSNULL;
gdt[slot].sd_xx3 = gdt_free;
gdt_free = slot;
}
int
tss_alloc(struct x86_64_tss *tss)
{
#ifndef XEN
int slot;
struct sys_segment_descriptor *gdt;
gdt = (struct sys_segment_descriptor *)&gdtstore[DYNSEL_START];
mutex_enter(&cpu_lock);
slot = gdt_get_slot();
#if 0
printf("tss_alloc: slot %d addr %p\n", slot, &gdt[slot]);
#endif
set_sys_gdt(&gdt[slot], tss, sizeof (struct x86_64_tss)-1,
SDT_SYS386TSS, SEL_KPL, 0);
mutex_exit(&cpu_lock);
#if 0
printf("lolimit %lx lobase %lx type %lx dpl %lx p %lx hilimit %lx\n"
"xx1 %lx gran %lx hibase %lx xx2 %lx zero %lx xx3 %lx pad %lx\n",
(unsigned long)gdt[slot].sd_lolimit,
(unsigned long)gdt[slot].sd_lobase,
(unsigned long)gdt[slot].sd_type,
(unsigned long)gdt[slot].sd_dpl,
(unsigned long)gdt[slot].sd_p,
(unsigned long)gdt[slot].sd_hilimit,
(unsigned long)gdt[slot].sd_xx1,
(unsigned long)gdt[slot].sd_gran,
(unsigned long)gdt[slot].sd_hibase,
(unsigned long)gdt[slot].sd_xx2,
(unsigned long)gdt[slot].sd_zero,
(unsigned long)gdt[slot].sd_xx3);
#endif
return GDYNSEL(slot, SEL_KPL);
#else /* XEN */
/* TSS, what for? */
return GSEL(GNULL_SEL, SEL_KPL);
#endif
}
void
tss_free(int sel)
{
#ifndef XEN
mutex_enter(&cpu_lock);
gdt_put_slot(IDXDYNSEL(sel));
mutex_exit(&cpu_lock);
#else
KASSERT(sel == GSEL(GNULL_SEL, SEL_KPL));
#endif
}
void
ldt_alloc(struct pmap *pmap, char *ldt, size_t len)
{
int slot;
struct sys_segment_descriptor *gdt;
KASSERT(mutex_owned(&cpu_lock));
gdt = (struct sys_segment_descriptor *)&gdtstore[DYNSEL_START];
slot = gdt_get_slot();
set_sys_gdt(&gdt[slot], ldt, len - 1, SDT_SYSLDT, SEL_KPL, 0);
pmap->pm_ldt_sel = GSEL(slot, SEL_KPL);
}
void
ldt_free(struct pmap *pmap)
{
int slot;
KASSERT(mutex_owned(&cpu_lock));
slot = IDXDYNSEL(pmap->pm_ldt_sel);
gdt_put_slot(slot);
}
#ifdef XEN
void
lgdt(desc)
struct region_descriptor *desc;
{
paddr_t frames[16];
int i;
vaddr_t va;
/*
* XXX: Xen even checks descriptors AFTER limit.
* Zero out last frame after limit if needed.
*/
va = desc->rd_base + desc->rd_limit + 1;
__PRINTK(("memset 0x%lx -> 0x%lx\n", va, roundup(va, PAGE_SIZE)));
memset((void *) va, 0, roundup(va, PAGE_SIZE) - va);
for (i = 0; i < roundup(desc->rd_limit,PAGE_SIZE) >> PAGE_SHIFT; i++) {
/*
* The lgdt instr uses virtual addresses, do some translation fo
r Xen.
* Mark pages R/O too, else Xen will refuse to use them
*/
frames[i] = ((paddr_t) xpmap_ptetomach(
(pt_entry_t *) (desc->rd_base + (i << PAGE_SHIFT
))))
>> PAGE_SHIFT;
__PRINTK(("frames[%d] = 0x%lx (pa 0x%lx)\n", i, frames[i],
xpmap_mtop(frames[i] << PAGE_SHIFT)));
pmap_pte_clearbits(kvtopte(desc->rd_base + (i << PAGE_SHIFT)),
PG_RW);
}
__PRINTK(("HYPERVISOR_set_gdt(%d)\n", (desc->rd_limit + 1) >> 3));
if (HYPERVISOR_set_gdt(frames, (desc->rd_limit + 1) >> 3))
panic("lgdt(): HYPERVISOR_set_gdt() failed");
lgdt_finish();
}
#endif