contiki/cpu/x86/mm/swseg-prot-domains.c
Michael LeMay e0aefd11d9 x86: Add support for SW-switched segment-based protection domains
This patch extends the protection domain framework with a third plugin
that is a hybrid of the previous two.  The hardware task switching
mechanism has a strictly-defined format for TSS data structures that
causes more space to be consumed than would otherwise be required.
This patch defines a smaller data structure that is allocated for each
protection domain, only requiring 32 bytes instead of 128 bytes.  It
uses the same multi-segment memory layout as the TSS-based plugin and
leaves paging disabled.  However, it uses a similar mechanism as the
paging plugin to perform system call dispatches and returns.

For additional information, please refer to cpu/x86/mm/README.md.
2016-04-22 08:16:43 -07:00

84 lines
3.2 KiB
C

/*
* Copyright (C) 2015, Intel Corporation. All rights reserved.
*
* 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.
*
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
* COPYRIGHT HOLDER 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.
*/
#include "gdt.h"
#include "helpers.h"
#include "multi-segment.h"
#include "prot-domains.h"
/*---------------------------------------------------------------------------*/
void
prot_domains_reg(dom_client_data_t ATTR_KERN_ADDR_SPACE *dcd,
uintptr_t mmio, size_t mmio_sz,
uintptr_t meta, size_t meta_sz,
bool pio)
{
volatile dom_kern_data_t ATTR_KERN_ADDR_SPACE *dkd;
dom_id_t dom_id;
KERN_READL(dom_id, dcd->dom_id);
if(PROT_DOMAINS_ACTUAL_CNT <= dom_id) {
halt();
}
dkd = prot_domains_kern_data + dom_id;
prot_domains_reg_multi_seg(dkd, mmio, mmio_sz, meta, meta_sz);
KERN_WRITEL(dkd->flags, pio ? PROT_DOMAINS_FLAG_PIO : 0);
}
/*---------------------------------------------------------------------------*/
static inline void __attribute__((always_inline))
prot_domains_switch(dom_id_t from_id, dom_id_t to_id,
interrupt_stack_t *intr_stk)
{
__asm__ __volatile__ (
"lldt %[_ldt_]\n\t"
"mov %[_meta_seg_], %%eax\n\t"
"lsl %%eax, %%ecx\n\t"
"jz 1f\n\t" /* ZF will only be set if the segment descriptor is valid. */
"xor %%eax, %%eax\n\t" /* Nullify metadata selector */
"1: mov %%eax, %%" SEG_META "s\n\t"
"mov %[_kern_seg_], %%eax\n\t"
"mov %%eax, %%" SEG_KERN "s\n\t"
:
: [_ldt_] "r" ((uint16_t)GDT_SEL_LDT(to_id)),
[_meta_seg_] "i" (LDT_SEL_META),
[_kern_seg_] "i" (LDT_SEL_KERN)
: "cc", "eax", "ecx"
);
}
/*---------------------------------------------------------------------------*/
/* Enable inter-procedural optimization with procedures in the following file:
*/
#include "syscalls-int.c"