/* * 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 #include #include #include #include #include #include #include #include /* * 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 idescriptor idt[IDT_ITEMS]; struct ptr_16_64 gdtr = {.limit = sizeof(gdt), .base= (__u64) &gdt }; struct ptr_16_64 idtr = {.limit = sizeof(idt), .base= (__u64) &idt }; static struct tss tss; struct tss *tss_p = NULL; /* 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 = gdtselector(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 *) gdtr.base; struct tss_descriptor *tss_desc; /* * 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_desc = (struct tss_descriptor *) (&gdt_p[TSS_DES]); tss_desc->present = 1; tss_desc->type = AR_TSS; tss_desc->dpl = PL_KERNEL; gdt_tss_setbase(&gdt_p[TSS_DES], (__address) tss_p); gdt_tss_setlimit(&gdt_p[TSS_DES], sizeof(struct tss) - 1); __asm__("lgdt %0" : : "m"(gdtr)); __asm__("lidt %0" : : "m"(idtr)); /* * 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 */ }