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correctly for the data contained on each memory page. There are several components to this change: * Add a variable to indicate the start of the R/W portion of the initial memory. * Stop detecting NX bit support for each AP. Instead, use the value from the BSP and, if supported, activate the feature on the other APs just before loading the correct page table. (Functionally, we already assume that the BSP and all APs had the same support or lack of support for the NX bit.) * Set the RW and NX bits correctly for the kernel text, data, and BSS (subject to some caveats below). * Ensure DDB can write to memory when necessary (such as to set a breakpoint). * Ensure GDB can write to memory when necessary (such as to set a breakpoint). For this purpose, add new MD functions gdb_begin_write() and gdb_end_write() which the GDB support code can call before and after writing to memory. This change is not comprehensive: * It doesn't do anything to protect modules. * It doesn't do anything for kernel memory allocated after the kernel starts running. * In order to avoid excessive memory inefficiency, it may let multiple types of data share a 2M page, and assigns the most permissions needed for data on that page. Reviewed by: jhb, kib Discussed with: emaste MFC after: 2 weeks Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D14282
98 lines
3.0 KiB
C
98 lines
3.0 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* William Jolitz.
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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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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR 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, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)cpu.h 5.4 (Berkeley) 5/9/91
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* $FreeBSD$
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*/
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#ifndef _MACHINE_CPU_H_
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#define _MACHINE_CPU_H_
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/*
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* Definitions unique to i386 cpu support.
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*/
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#include <machine/psl.h>
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#include <machine/frame.h>
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#include <machine/segments.h>
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#define cpu_exec(p) /* nothing */
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#define cpu_swapin(p) /* nothing */
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#define cpu_getstack(td) ((td)->td_frame->tf_rsp)
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#define cpu_setstack(td, ap) ((td)->td_frame->tf_rsp = (ap))
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#define cpu_spinwait() ia32_pause()
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#define TRAPF_USERMODE(framep) \
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(ISPL((framep)->tf_cs) == SEL_UPL)
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#define TRAPF_PC(framep) ((framep)->tf_rip)
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#ifdef _KERNEL
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/*
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* Struct containing pointers to CPU management functions whose
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* implementation is run time selectable. Selection can be made,
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* for example, based on detection of a particular CPU variant or
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* hypervisor environment.
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*/
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struct cpu_ops {
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void (*cpu_init)(void);
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void (*cpu_resume)(void);
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};
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extern struct cpu_ops cpu_ops;
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extern char brwsection[];
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extern char btext[];
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extern char _end[];
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extern char etext[];
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/* Resume hook for VMM. */
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extern void (*vmm_resume_p)(void);
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void cpu_halt(void);
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void cpu_reset(void);
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void fork_trampoline(void);
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void swi_vm(void *);
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/*
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* Return contents of in-cpu fast counter as a sort of "bogo-time"
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* for random-harvesting purposes.
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*/
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static __inline u_int64_t
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get_cyclecount(void)
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{
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return (rdtsc());
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}
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#endif
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#endif /* !_MACHINE_CPU_H_ */
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