mirror of
https://github.com/oliverschmidt/contiki.git
synced 2024-06-29 18:29:41 +00:00
e0aefd11d9
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.
110 lines
4.3 KiB
C
110 lines
4.3 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.
|
|
*/
|
|
|
|
#ifndef CPU_X86_MM_STACKS_H_
|
|
#define CPU_X86_MM_STACKS_H_
|
|
|
|
#include "prot-domains.h"
|
|
|
|
#if X86_CONF_PROT_DOMAINS == X86_CONF_PROT_DOMAINS__NONE
|
|
#define STACKS_SIZE_INT 0
|
|
#else
|
|
/**
|
|
* The necessary amount of space for the interrupt and exception stacks is
|
|
* determined by the amount of data pushed on the stack by the CPU when
|
|
* delivering an interrupt or exception, and by the additional data pushed
|
|
* on the stack by the interrupt dispatcher. See interrupt.h for more details.
|
|
*/
|
|
#define STACKS_SIZE_INT (14 * 4)
|
|
#endif
|
|
|
|
#if X86_CONF_PROT_DOMAINS == X86_CONF_PROT_DOMAINS__PAGING
|
|
/**
|
|
* The system call and return dispatchers use this stack, so its size was
|
|
* determined by observing their behavior. It is possible that the dispatchers
|
|
* could overflow the stack and overwrite data on the other stacks. An
|
|
* alternative design that would facilitate detection of such overflows would
|
|
* place the exception handler stack on a separate page surrounded by guard
|
|
* bands, but that would consume a substantial amount of additional memory.
|
|
*
|
|
* All stack sizes should be a multiple of 4 to accommodate a 4-byte alignment.
|
|
*/
|
|
#ifdef __clang__
|
|
#define STACKS_SIZE_EXC 512
|
|
#else
|
|
#define STACKS_SIZE_EXC 256
|
|
#endif
|
|
#elif X86_CONF_PROT_DOMAINS == X86_CONF_PROT_DOMAINS__SWSEG
|
|
#ifdef __clang__
|
|
#define STACKS_SIZE_EXC 512
|
|
#else
|
|
#define STACKS_SIZE_EXC 256
|
|
#endif
|
|
#elif X86_CONF_PROT_DOMAINS == X86_CONF_PROT_DOMAINS__TSS
|
|
/**
|
|
* This should be large enough to execute the exception handler with the
|
|
* largest stack requirement: double_fault_handler:
|
|
* - 1 word for the return address from calling double_fault_handler
|
|
* - 1 word for the saved frame pointer in double_fault_handler
|
|
* - 2 words that GCC has been observed to skip on the stack to align it
|
|
* to a preferred boundary
|
|
* - 1 word for the return address for calling halt
|
|
*/
|
|
#define STACKS_SIZE_EXC (STACKS_SIZE_INT + (6 * 4))
|
|
#else
|
|
#define STACKS_SIZE_EXC STACKS_SIZE_INT
|
|
#endif
|
|
/**
|
|
* The combined size of the stacks should be an even multiple of the 4K page
|
|
* size so that they precisely fill some number of pages when paging-based
|
|
* protection domains are in use. The stacks are arranged contiguously by
|
|
* the linker scripts. See those and README.md for more details.
|
|
*/
|
|
#define STACKS_SIZE_MAIN (8192 - (STACKS_SIZE_INT + STACKS_SIZE_EXC))
|
|
|
|
#if !__ASSEMBLER__
|
|
/**
|
|
* Stack for exception handlers. Also used for system call and return
|
|
* dispatchers when paging-based protection domains are enabled.
|
|
*/
|
|
extern uint8_t stacks_exc[STACKS_SIZE_EXC];
|
|
/** Stack for interrupt handlers. */
|
|
extern uint8_t stacks_int[STACKS_SIZE_INT];
|
|
/** Main C stack. */
|
|
extern uint8_t stacks_main[STACKS_SIZE_MAIN];
|
|
|
|
#define STACKS_INIT_TOP \
|
|
((uintptr_t)stacks_main + STACKS_SIZE_MAIN - \
|
|
(PROT_DOMAINS_INIT_RET_ADDR_CNT * sizeof(uintptr_t)))
|
|
|
|
#endif
|
|
|
|
#endif /* CPU_X86_MM_STACKS_H_ */
|