/*
* 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.
*/
/** @addtogroup ia32
* @{
*/
/** @file
*/
#include <arch/pm.h>
#include <config.h>
#include <arch/types.h>
#include <typedefs.h>
#include <arch/interrupt.h>
#include <arch/asm.h>
#include <arch/context.h>
#include <panic.h>
#include <arch/mm/page.h>
#include <mm/slab.h>
#include <memstr.h>
#include <arch/boot/boot.h>
#include <interrupt.h>
/*
* Early ia32 configuration functions and data structures.
*/
/*
* We have no use for segmentation 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.
*
* One is for GS register which holds pointer to the TLS thread
* structure in it's base.
*/
descriptor_t gdt[GDT_ITEMS] = {
/* NULL descriptor */
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
/* KTEXT descriptor */
{ 0xffff, 0, 0, AR_PRESENT | AR_CODE | DPL_KERNEL, 0xf, 0, 0, 1, 1, 0 },
/* KDATA descriptor */
{ 0xffff, 0, 0, AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_KERNEL, 0xf, 0, 0, 1, 1, 0 },
/* UTEXT descriptor */
{ 0xffff, 0, 0, AR_PRESENT | AR_CODE | DPL_USER, 0xf, 0, 0, 1, 1, 0 },
/* UDATA descriptor */
{ 0xffff, 0, 0, AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_USER, 0xf, 0, 0, 1, 1, 0 },
/* TSS descriptor - set up will be completed later */
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
/* TLS descriptor */
{ 0xffff, 0, 0, AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_USER, 0xf, 0, 0, 1, 1, 0 },
/* VESA Init descriptor */
#ifdef CONFIG_FB
{ 0xffff, 0, VESA_INIT_SEGMENT>>12, AR_PRESENT | AR_CODE | DPL_KERNEL, 0xf, 0, 0, 0, 0, 0 }
#endif
};
static idescriptor_t idt[IDT_ITEMS];
static tss_t tss;
tss_t *tss_p = NULL;
/* gdtr is changed by kmp before next CPU is initialized */
ptr_16_32_t bootstrap_gdtr = { .limit = sizeof(gdt), .base = KA2PA((uintptr_t) gdt) };
ptr_16_32_t gdtr = { .limit = sizeof(gdt), .base = (uintptr_t) gdt };
void gdt_setbase(descriptor_t *d, uintptr_t base)
{
d->base_0_15 = base & 0xffff;
d->base_16_23 = ((base) >> 16) & 0xff;
d->base_24_31 = ((base) >> 24) & 0xff;
}
void gdt_setlimit(descriptor_t *d, uint32_t limit)
{
d->limit_0_15 = limit & 0xffff;
d->limit_16_19 = (limit >> 16) & 0xf;
}
void idt_setoffset(idescriptor_t *d, uintptr_t offset)
{
/*
* Offset is a linear address.
*/
d->offset_0_15 = offset & 0xffff;
d->offset_16_31 = offset >> 16;
}
void tss_initialize(tss_t *t)
{
memsetb((uintptr_t) t, sizeof(struct tss), 0);
}
/*
* This function takes care of proper setup of IDT and IDTR.
*/
void idt_init(void)
{
idescriptor_t *d;
int i;
for (i = 0; i < IDT_ITEMS; i++) {
d = &idt[i];
d->unused = 0;
d->selector = selector(KTEXT_DES);
d->access = AR_PRESENT | AR_INTERRUPT; /* masking interrupt */
if (i == VECTOR_SYSCALL) {
/*
* The syscall interrupt gate must be calleable from userland.
*/
d->access |= DPL_USER;
}
idt_setoffset(d, ((uintptr_t) interrupt_handlers) + i * interrupt_handler_size);
}
}
/* Clean IOPL(12,13) and NT(14) flags in EFLAGS register */
static void clean_IOPL_NT_flags(void)
{
asm volatile (
"pushfl\n"
"pop %%eax\n"
"and $0xffff8fff, %%eax\n"
"push %%eax\n"
"popfl\n"
: : : "eax"
);
}
/* Clean AM(18) flag in CR0 register */
static void clean_AM_flag(void)
{
asm volatile (
"mov %%cr0, %%eax\n"
"and $0xfffbffff, %%eax\n"
"mov %%eax, %%cr0\n"
: : : "eax"
);
}
void pm_init(void)
{
descriptor_t *gdt_p = (descriptor_t *) gdtr.base;
ptr_16_32_t idtr;
/*
* Update addresses in GDT and IDT to their virtual counterparts.
*/
idtr.limit = sizeof(idt);
idtr.base = (uintptr_t) idt;
gdtr_load(&gdtr);
idtr_load(&idtr);
/*
* 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
= (tss_t
*) malloc(sizeof(tss_t
), FRAME_ATOMIC
); if (!tss_p)
panic("could not allocate TSS\n");
}
tss_initialize(tss_p);
gdt_p[TSS_DES].access = AR_PRESENT | AR_TSS | DPL_KERNEL;
gdt_p[TSS_DES].special = 1;
gdt_p[TSS_DES].granularity = 0;
gdt_setbase(&gdt_p[TSS_DES], (uintptr_t) tss_p);
gdt_setlimit(&gdt_p[TSS_DES], TSS_BASIC_SIZE - 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.
*/
tr_load(selector(TSS_DES));
clean_IOPL_NT_flags(); /* Disable I/O on nonprivileged levels and clear NT flag. */
clean_AM_flag(); /* Disable alignment check */
}
void set_tls_desc(uintptr_t tls)
{
ptr_16_32_t cpugdtr;
descriptor_t *gdt_p;
gdtr_store(&cpugdtr);
gdt_p = (descriptor_t *) cpugdtr.base;
gdt_setbase(&gdt_p[TLS_DES], tls);
/* Reload gdt register to update GS in CPU */
gdtr_load(&cpugdtr);
}
/** @}
*/