4cdb7ba9b6
This patch extends the protection domain framework with an additional plugin to use Task-State Segment (TSS) structures to offload much of the work of switching protection domains to the CPU. This can save space compared to paging, since paging requires two 4KiB page tables and one 32-byte page table plus one whole-system TSS and an additional 32-byte data structure for each protection domain, whereas the approach implemented by this patch just requires a 128-byte data structure for each protection domain. Only a small number of protection domains will typically be used, so n * 128 < 8328 + (n * 32). For additional information, please refer to cpu/x86/mm/README.md. GCC 6 is introducing named address spaces for the FS and GS segments [1]. LLVM Clang also provides address spaces for the FS and GS segments [2]. This patch also adds support to the multi-segment X86 memory management subsystem for using these features instead of inline assembly blocks, which enables type checking to detect some address space mismatches. [1] https://gcc.gnu.org/onlinedocs/gcc/Named-Address-Spaces.html [2] http://llvm.org/releases/3.3/tools/clang/docs/LanguageExtensions.html#target-specific-extensions
162 lines
5.9 KiB
C
162 lines
5.9 KiB
C
/*
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* Copyright (C) 2015-2016, Intel Corporation. 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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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* 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,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stdint.h>
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#include <string.h>
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#include "gdt.h"
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#include "helpers.h"
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#include "idt.h"
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#include "prot-domains.h"
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#include "stacks.h"
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#include "syscalls.h"
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#include "tss.h"
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uint32_t prot_domains_main_esp;
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syscalls_entrypoint_t ATTR_KERN_ADDR_SPACE *prot_domains_syscall;
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/*---------------------------------------------------------------------------*/
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void app_main(void);
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void
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prot_domains_reg(dom_client_data_t ATTR_KERN_ADDR_SPACE *dcd,
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uintptr_t mmio, size_t mmio_sz,
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uintptr_t meta, size_t meta_sz,
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bool pio)
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{
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segment_desc_t desc;
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uint32_t eflags;
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dom_id_t dom_id;
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volatile struct dom_kern_data ATTR_KERN_ADDR_SPACE *dkd;
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KERN_READL(dom_id, dcd->dom_id);
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dkd = prot_domains_kern_data + dom_id;
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prot_domains_reg_multi_seg(dkd, mmio, mmio_sz, meta, meta_sz);
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/* Only the kernel protection domain requires port I/O access outside of the
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* interrupt handlers.
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*/
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eflags = EFLAGS_IOPL(pio ? PRIV_LVL_USER : PRIV_LVL_INT);
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if(dom_id == DOM_ID_app) {
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eflags |= EFLAGS_IF;
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}
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/* Keep this initialization in sync with the register definitions in
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* tss-prot-domains-asm.S.
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*/
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KERN_WRITEL(dkd->tss.ebp, 0);
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KERN_WRITEL(dkd->tss.ebx, 0);
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KERN_WRITEL(dkd->tss.esi, BIT(dom_id));
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KERN_WRITEL(dkd->tss.eip,
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(dom_id == DOM_ID_app) ?
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(uint32_t)app_main :
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(uint32_t)prot_domains_syscall_dispatcher);
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KERN_WRITEL(dkd->tss.cs, GDT_SEL_CODE);
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KERN_WRITEL(dkd->tss.ds, GDT_SEL_DATA);
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KERN_WRITEL(dkd->tss.es, GDT_SEL_DATA);
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KERN_WRITEL(dkd->tss.fs, LDT_SEL_KERN);
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KERN_WRITEL(dkd->tss.gs,
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(meta_sz == 0) ? GDT_SEL_NULL : LDT_SEL_META);
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KERN_WRITEL(dkd->tss.ss, GDT_SEL_STK);
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/* This stack pointer is only actually used in application protection domain.
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* Other domains enter at system call dispatcher, which switches to main
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* stack.
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*/
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KERN_WRITEL(dkd->tss.esp,
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/* Two return addresses have been consumed: */
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STACKS_INIT_TOP + (2 * sizeof(uintptr_t)));
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KERN_WRITEL(dkd->tss.eflags, eflags);
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KERN_WRITEL(dkd->tss.ldt, GDT_SEL_LDT(dom_id));
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KERN_WRITEL(dkd->tss.esp2, STACKS_SIZE_MAIN + STACKS_SIZE_INT);
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KERN_WRITEL(dkd->tss.ss2, GDT_SEL_STK_INT);
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KERN_WRITEL(dkd->tss.esp0,
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STACKS_SIZE_MAIN + STACKS_SIZE_INT + STACKS_SIZE_EXC);
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KERN_WRITEL(dkd->tss.ss0, GDT_SEL_STK_EXC);
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KERN_WRITEW(dkd->tss.t, 0);
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KERN_WRITEW(dkd->tss.iomap_base, sizeof(tss_t));
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KERN_WRITEL(dkd->tss.cr3, 0);
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segment_desc_init(&desc,
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KERN_DATA_OFF_TO_PHYS_ADDR((uint32_t)&(dkd->tss)),
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sizeof(dkd->tss),
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/* It should be possible for code at any privilege level to invoke the task's
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* system call dispatcher.
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*/
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SEG_FLAG(DPL, PRIV_LVL_USER) | SEG_TYPE_TSS32_AVAIL);
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gdt_insert(GDT_IDX_TSS(dom_id), desc);
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KERN_WRITEW(dcd->tss_sel, GDT_SEL(GDT_IDX_TSS(dom_id), PRIV_LVL_USER));
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}
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/*---------------------------------------------------------------------------*/
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void dev_not_avail_isr(void);
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void
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prot_domains_impl_init(void)
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{
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__asm__ __volatile__ ("ltr %0" :: "r" ((uint16_t)GDT_SEL_TSS(DOM_ID_kern)));
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__asm__ __volatile__ ("lldt %0" :: "r" ((uint16_t)GDT_SEL_LDT(DOM_ID_kern)));
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idt_set_intr_gate_desc(7,
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(uint32_t)dev_not_avail_isr,
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GDT_SEL_CODE_EXC, PRIV_LVL_EXC);
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}
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/*---------------------------------------------------------------------------*/
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int main();
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void
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prot_domains_launch_kernel(void)
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{
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multi_segment_launch_kernel();
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/* Activate kernel protection domain, entering the kernel at main. */
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__asm__ __volatile__ (
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"pushl %[_ss_]\n\t"
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"pushl %[_top_of_stk_]\n\t"
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"pushl %[_eflags_]\n\t"
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"pushl %[_cs_]\n\t"
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"pushl %[_kern_start_]\n\t"
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"iretl\n\t"
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:
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: [_ss_] "g" (GDT_SEL_STK),
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[_eflags_] "g" (EFLAGS_IOPL(PRIV_LVL_USER)),
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[_cs_] "g" (GDT_SEL_CODE),
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[_kern_start_] "g" (main),
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/* one address has already been consumed */
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[_top_of_stk_] "g" (STACKS_INIT_TOP + sizeof(uint32_t))
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);
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}
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/*---------------------------------------------------------------------------*/
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void
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prot_domains_launch_app()
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{
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far_pointer_t app_ptr = { 0, GDT_SEL_TSS(DOM_ID_app) };
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__asm__ __volatile__ ("ljmp *%0" :: "m" (app_ptr));
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}
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/*---------------------------------------------------------------------------*/
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