/*
* Copyright (C) 2001-2004 Jakub Jermar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
#include <arch/pm.h>
#include <arch/mm/page.h>
#include <arch/types.h>
#include <arch/interrupt.h>
#include <arch/asm.h>
#include <config.h>
#include <memstr.h>
#include <mm/heap.h>
#include <debug.h>
/*
* There is no segmentation in long mode so we set up flat mode. In this
* mode, we use, for each privilege level, two segments spanning the
* whole memory. One is for code and one is for data.
*/
struct descriptor gdt[GDT_ITEMS] = {
/* NULL descriptor */
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
/* KTEXT descriptor */
{ .limit_0_15 = 0xffff,
.base_0_15 = 0,
.base_16_23 = 0,
.access = AR_PRESENT | AR_CODE | DPL_KERNEL | AR_READABLE ,
.limit_16_19 = 0xf,
.available = 0,
.longmode = 1,
.special = 0,
.granularity = 1,
.base_24_31 = 0 },
/* KDATA descriptor */
{ .limit_0_15 = 0xffff,
.base_0_15 = 0,
.base_16_23 = 0,
.access = AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_KERNEL,
.limit_16_19 = 0xf,
.available = 0,
.longmode = 0,
.special = 0,
.granularity = 1,
.base_24_31 = 0 },
/* UTEXT descriptor */
{ .limit_0_15 = 0xffff,
.base_0_15 = 0,
.base_16_23 = 0,
.access = AR_PRESENT | AR_CODE | DPL_USER,
.limit_16_19 = 0xf,
.available = 0,
.longmode = 1,
.special = 0,
.granularity = 1,
.base_24_31 = 0 },
/* UDATA descriptor */
{ .limit_0_15 = 0xffff,
.base_0_15 = 0,
.base_16_23 = 0,
.access = AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_USER,
.limit_16_19 = 0xf,
.available = 0,
.longmode = 0,
.special = 1,
.granularity = 1,
.base_24_31 = 0 },
/* KTEXT 16-bit protected */
{ .limit_0_15 = 0xffff,
.base_0_15 = 0,
.base_16_23 = 0,
.access = AR_PRESENT | AR_CODE | DPL_KERNEL | AR_READABLE,
.limit_16_19 = 0xf,
.available = 0,
.longmode = 0,
.special = 0,
.granularity = 1,
.base_24_31 = 0 },
/* TSS descriptor - set up will be completed later,
* on AMD64 it is 64-bit - 2 items in table */
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
};
struct ptr_16_64 gdtr = {.limit = sizeof(gdtr), .base= (__u64) &gdtr };
struct idescriptor idt[IDT_ITEMS];
static struct tss tss;
/* TODO: Does not compile correctly if it does not exist ???? */
int __attribute__ ((section ("K_DATA_START"))) __fake;
void gdt_tss_setbase(struct descriptor *d, __address base)
{
struct tss_descriptor *td = (struct tss_descriptor *) d;
td->base_0_15 = base & 0xffff;
td->base_16_23 = ((base) >> 16) & 0xff;
td->base_24_31 = ((base) >> 24) & 0xff;
td->base_32_63 = ((base) >> 32);
}
void gdt_tss_setlimit(struct descriptor *d, __u32 limit)
{
struct tss_descriptor *td = (struct tss_descriptor *) d;
td->limit_0_15 = limit & 0xffff;
td->limit_16_19 = (limit >> 16) & 0xf;
}
void idt_setoffset(struct idescriptor *d, __address offset)
{
/*
* Offset is a linear address.
*/
d->offset_0_15 = offset & 0xffff;
d->offset_16_31 = offset >> 16 & 0xffff;
d->offset_32_63 = offset >> 32;
}
void tss_initialize(struct tss *t)
{
memsetb((__address) t, sizeof(struct tss), 0);
}
/*
* This function takes care of proper setup of IDT and IDTR.
*/
void idt_init(void)
{
struct idescriptor *d;
int i;
for (i = 0; i < IDT_ITEMS; i++) {
d = &idt[i];
d->unused = 0;
d->selector = idtselector(KTEXT_DES);
d->present = 1;
d->type = AR_INTERRUPT; /* masking interrupt */
if (i == VECTOR_SYSCALL) {
/*
* The syscall interrupt gate must be calleable from userland.
*/
d->dpl |= PL_USER;
}
idt_setoffset(d, ((__address) interrupt_handlers) + i*interrupt_handler_size);
trap_register(i, null_interrupt);
}
trap_register(13, gp_fault);
trap_register( 7, nm_fault);
trap_register(12, ss_fault);
}
/* Clean IOPL(12,13) and NT(14) flags in EFLAGS register */
static void clean_IOPL_NT_flags(void)
{
asm
(
"pushfq;"
"pop %%rax;"
"and $~(0x7000),%%rax;"
"pushq %%rax;"
"popfq;"
:
:
:"%rax"
);
}
/* Clean AM(18) flag in CR0 register */
static void clean_AM_flag(void)
{
asm
(
"mov %%cr0,%%rax;"
"and $~(0x40000),%%rax;"
"mov %%rax,%%cr0;"
:
:
:"%rax"
);
}
void pm_init(void)
{
struct descriptor *gdt_p = (struct descriptor *) PA2KA(gdtr.base);
struct tss_descriptor *tss_d;
/*
* Each CPU has its private GDT and TSS.
* All CPUs share one IDT.
*/
if (config.cpu_active == 1) {
idt_init();
/*
* NOTE: bootstrap CPU has statically allocated TSS, because
* the heap hasn't been initialized so far.
*/
tss_p = &tss;
}
else {
tss_p
= (struct tss
*) malloc(sizeof(struct tss
)); if (!tss_p)
panic("could not allocate TSS\n");
}
tss_initialize(tss_p);
tss_d = (struct tss_descriptor *) &gdt_p[TSS_DES];
tss_d[TSS_DES].present = 1;
tss_d[TSS_DES].type = AR_TSS;
tss_d[TSS_DES].dpl = PL_KERNEL;
gdt_tss_setbase(&gdt_p[TSS_DES], (__address) tss_p);
gdt_tss_setlimit(&gdt_p[TSS_DES], sizeof(struct tss) - 1);
/*
* As of this moment, the current CPU has its own GDT pointing
* to its own TSS. We just need to load the TR register.
*/
__asm__("ltr %0" : : "r" ((__u16) gdtselector(TSS_DES)));
clean_IOPL_NT_flags(); /* Disable I/O on nonprivileged levels */
clean_AM_flag(); /* Disable alignment check */
}