c862dd3ee0
On amd64, arm64 and i386, we have the possibility to switch between TLS areas in userspace. The nice thing about this is that it makes it easier to do light-weight threading, if we ever feel like doing that. On armv6, let's go into the same direction by making it possible to safely use the TPIDRURW register, which is intended for this purpose. Clean up the ARMv6 code to remove md_tp entirely. Simply add a dedicated field to the PCB to hold the value of TPIDRURW across context switches, like we do for any other register. As userspace currently uses the read-only TPIDRURO register, simply ensure that we keep both values in sync where possible. The system calls for modifying the read-only register will simply write the intended value into both registers, so that it lazily ends up in the PCB during the next context switch. Reviewed by: https://reviews.freebsd.org/D7951 Approved by: andrew Reviewed by: imp Differential Revision: https://reviews.freebsd.org/D7951
142 lines
3.6 KiB
C
142 lines
3.6 KiB
C
/*-
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* Copyright (c) 1999 Luoqi Chen <luoqi@freebsd.org>
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* 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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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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: FreeBSD: src/sys/i386/include/globaldata.h,v 1.27 2001/04/27
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* $FreeBSD$
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*/
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#ifndef _MACHINE_PCPU_H_
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#define _MACHINE_PCPU_H_
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#ifdef _KERNEL
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#include <machine/cpuconf.h>
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#define ALT_STACK_SIZE 128
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struct vmspace;
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#endif /* _KERNEL */
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#if __ARM_ARCH >= 6
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#define PCPU_MD_FIELDS \
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unsigned int pc_vfpsid; \
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unsigned int pc_vfpmvfr0; \
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unsigned int pc_vfpmvfr1; \
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struct pmap *pc_curpmap; \
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vm_offset_t pc_qmap_addr; \
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void *pc_qmap_pte; \
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unsigned int pc_dbreg[32]; \
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int pc_dbreg_cmd; \
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char __pad[1]
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#else
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#define PCPU_MD_FIELDS \
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vm_offset_t qmap_addr; \
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void *pc_qmap_pte; \
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char __pad[149]
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#endif
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#ifdef _KERNEL
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#define PC_DBREG_CMD_NONE 0
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#define PC_DBREG_CMD_LOAD 1
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struct pcb;
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struct pcpu;
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extern struct pcpu *pcpup;
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#if __ARM_ARCH >= 6
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#define CPU_MASK (0xf)
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#ifndef SMP
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#define get_pcpu() (pcpup)
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#else
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#define get_pcpu() __extension__ ({ \
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int id; \
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__asm __volatile("mrc p15, 0, %0, c0, c0, 5" : "=r" (id)); \
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(pcpup + (id & CPU_MASK)); \
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})
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#endif
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static inline struct thread *
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get_curthread(void)
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{
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void *ret;
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__asm __volatile("mrc p15, 0, %0, c13, c0, 4" : "=r" (ret));
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return (ret);
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}
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static inline void
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set_curthread(struct thread *td)
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{
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__asm __volatile("mcr p15, 0, %0, c13, c0, 4" : : "r" (td));
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}
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static inline void *
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get_tls(void)
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{
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void *tls;
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/* TPIDRURW contains the authoritative value. */
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__asm __volatile("mrc p15, 0, %0, c13, c0, 2" : "=r" (tls));
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return (tls);
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}
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static inline void
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set_tls(void *tls)
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{
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/*
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* Update both TPIDRURW and TPIDRURO. TPIDRURW needs to be written
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* first to ensure that a context switch between the two writes will
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* still give the desired result of updating both.
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*/
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__asm __volatile(
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"mcr p15, 0, %0, c13, c0, 2\n"
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"mcr p15, 0, %0, c13, c0, 3\n"
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: : "r" (tls));
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}
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#define curthread get_curthread()
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#else
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#define get_pcpu() pcpup
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#endif
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#define PCPU_GET(member) (get_pcpu()->pc_ ## member)
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#define PCPU_ADD(member, value) (get_pcpu()->pc_ ## member += (value))
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#define PCPU_INC(member) PCPU_ADD(member, 1)
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#define PCPU_PTR(member) (&get_pcpu()->pc_ ## member)
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#define PCPU_SET(member,value) (get_pcpu()->pc_ ## member = (value))
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void pcpu0_init(void);
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#endif /* _KERNEL */
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#endif /* !_MACHINE_PCPU_H_ */
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