393 lines
11 KiB
C
393 lines
11 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2010, 2012 Konstantin Belousov <kib@FreeBSD.org>
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* Copyright (c) 2015 The FreeBSD Foundation
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* All rights reserved.
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*
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* Portions of this software were developed by Konstantin Belousov
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* under sponsorship from the FreeBSD Foundation.
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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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#include <sys/cdefs.h>
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#include "opt_vm.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/rwlock.h>
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#include <sys/stddef.h>
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#include <sys/sysent.h>
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#include <sys/sysctl.h>
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#include <sys/vdso.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/pmap.h>
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#include <vm/vm_extern.h>
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#include <vm/vm_kern.h>
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#include <vm/vm_map.h>
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#include <vm/vm_object.h>
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#include <vm/vm_page.h>
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#include <vm/vm_pager.h>
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static struct sx shared_page_alloc_sx;
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static vm_object_t shared_page_obj;
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static int shared_page_free;
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char *shared_page_mapping;
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#ifdef RANDOM_FENESTRASX
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static struct vdso_fxrng_generation *fxrng_shpage_mapping;
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static bool fxrng_enabled = true;
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SYSCTL_BOOL(_debug, OID_AUTO, fxrng_vdso_enable, CTLFLAG_RWTUN, &fxrng_enabled,
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0, "Enable FXRNG VDSO");
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#endif
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void
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shared_page_write(int base, int size, const void *data)
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{
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bcopy(data, shared_page_mapping + base, size);
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}
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static int
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shared_page_alloc_locked(int size, int align)
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{
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int res;
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res = roundup(shared_page_free, align);
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if (res + size >= IDX_TO_OFF(shared_page_obj->size))
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res = -1;
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else
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shared_page_free = res + size;
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return (res);
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}
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int
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shared_page_alloc(int size, int align)
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{
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int res;
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sx_xlock(&shared_page_alloc_sx);
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res = shared_page_alloc_locked(size, align);
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sx_xunlock(&shared_page_alloc_sx);
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return (res);
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}
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int
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shared_page_fill(int size, int align, const void *data)
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{
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int res;
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sx_xlock(&shared_page_alloc_sx);
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res = shared_page_alloc_locked(size, align);
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if (res != -1)
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shared_page_write(res, size, data);
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sx_xunlock(&shared_page_alloc_sx);
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return (res);
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}
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static void
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shared_page_init(void *dummy __unused)
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{
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vm_page_t m;
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vm_offset_t addr;
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sx_init(&shared_page_alloc_sx, "shpsx");
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shared_page_obj = vm_pager_allocate(OBJT_PHYS, 0, PAGE_SIZE,
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VM_PROT_DEFAULT, 0, NULL);
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VM_OBJECT_WLOCK(shared_page_obj);
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m = vm_page_grab(shared_page_obj, 0, VM_ALLOC_ZERO);
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VM_OBJECT_WUNLOCK(shared_page_obj);
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vm_page_valid(m);
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vm_page_xunbusy(m);
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addr = kva_alloc(PAGE_SIZE);
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pmap_qenter(addr, &m, 1);
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shared_page_mapping = (char *)addr;
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}
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SYSINIT(shp, SI_SUB_EXEC, SI_ORDER_FIRST, (sysinit_cfunc_t)shared_page_init,
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NULL);
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/*
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* Push the timehands update to the shared page.
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*
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* The lockless update scheme is similar to the one used to update the
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* in-kernel timehands, see sys/kern/kern_tc.c:tc_windup() (which
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* calls us after the timehands are updated).
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*/
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static void
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timehands_update(struct vdso_sv_tk *svtk)
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{
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struct vdso_timehands th;
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struct vdso_timekeep *tk;
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uint32_t enabled, idx;
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enabled = tc_fill_vdso_timehands(&th);
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th.th_gen = 0;
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idx = svtk->sv_timekeep_curr;
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if (++idx >= VDSO_TH_NUM)
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idx = 0;
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svtk->sv_timekeep_curr = idx;
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if (++svtk->sv_timekeep_gen == 0)
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svtk->sv_timekeep_gen = 1;
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tk = (struct vdso_timekeep *)(shared_page_mapping +
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svtk->sv_timekeep_off);
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tk->tk_th[idx].th_gen = 0;
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atomic_thread_fence_rel();
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if (enabled)
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tk->tk_th[idx] = th;
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atomic_store_rel_32(&tk->tk_th[idx].th_gen, svtk->sv_timekeep_gen);
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atomic_store_rel_32(&tk->tk_current, idx);
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/*
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* The ordering of the assignment to tk_enabled relative to
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* the update of the vdso_timehands is not important.
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*/
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tk->tk_enabled = enabled;
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}
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#ifdef COMPAT_FREEBSD32
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static void
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timehands_update32(struct vdso_sv_tk *svtk)
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{
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struct vdso_timehands32 th;
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struct vdso_timekeep32 *tk;
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uint32_t enabled, idx;
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enabled = tc_fill_vdso_timehands32(&th);
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th.th_gen = 0;
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idx = svtk->sv_timekeep_curr;
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if (++idx >= VDSO_TH_NUM)
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idx = 0;
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svtk->sv_timekeep_curr = idx;
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if (++svtk->sv_timekeep_gen == 0)
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svtk->sv_timekeep_gen = 1;
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tk = (struct vdso_timekeep32 *)(shared_page_mapping +
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svtk->sv_timekeep_off);
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tk->tk_th[idx].th_gen = 0;
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atomic_thread_fence_rel();
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if (enabled)
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tk->tk_th[idx] = th;
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atomic_store_rel_32(&tk->tk_th[idx].th_gen, svtk->sv_timekeep_gen);
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atomic_store_rel_32(&tk->tk_current, idx);
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tk->tk_enabled = enabled;
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}
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#endif
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/*
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* This is hackish, but easiest way to avoid creating list structures
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* that needs to be iterated over from the hardclock interrupt
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* context.
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*/
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static struct vdso_sv_tk *host_svtk;
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#ifdef COMPAT_FREEBSD32
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static struct vdso_sv_tk *compat32_svtk;
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#endif
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void
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timekeep_push_vdso(void)
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{
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if (host_svtk != NULL)
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timehands_update(host_svtk);
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#ifdef COMPAT_FREEBSD32
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if (compat32_svtk != NULL)
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timehands_update32(compat32_svtk);
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#endif
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}
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struct vdso_sv_tk *
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alloc_sv_tk(void)
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{
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struct vdso_sv_tk *svtk;
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int tk_base;
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uint32_t tk_ver;
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tk_ver = VDSO_TK_VER_CURR;
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svtk = malloc(sizeof(struct vdso_sv_tk), M_TEMP, M_WAITOK | M_ZERO);
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tk_base = shared_page_alloc(sizeof(struct vdso_timekeep) +
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sizeof(struct vdso_timehands) * VDSO_TH_NUM, 16);
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KASSERT(tk_base != -1, ("tk_base -1 for native"));
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shared_page_write(tk_base + offsetof(struct vdso_timekeep, tk_ver),
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sizeof(uint32_t), &tk_ver);
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svtk->sv_timekeep_off = tk_base;
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timekeep_push_vdso();
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return (svtk);
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}
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#ifdef COMPAT_FREEBSD32
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struct vdso_sv_tk *
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alloc_sv_tk_compat32(void)
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{
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struct vdso_sv_tk *svtk;
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int tk_base;
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uint32_t tk_ver;
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svtk = malloc(sizeof(struct vdso_sv_tk), M_TEMP, M_WAITOK | M_ZERO);
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tk_ver = VDSO_TK_VER_CURR;
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tk_base = shared_page_alloc(sizeof(struct vdso_timekeep32) +
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sizeof(struct vdso_timehands32) * VDSO_TH_NUM, 16);
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KASSERT(tk_base != -1, ("tk_base -1 for 32bit"));
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shared_page_write(tk_base + offsetof(struct vdso_timekeep32,
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tk_ver), sizeof(uint32_t), &tk_ver);
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svtk->sv_timekeep_off = tk_base;
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timekeep_push_vdso();
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return (svtk);
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}
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#endif
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#ifdef RANDOM_FENESTRASX
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void
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fxrng_push_seed_generation(uint64_t gen)
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{
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if (fxrng_shpage_mapping == NULL || !fxrng_enabled)
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return;
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KASSERT(gen < INT32_MAX,
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("fxrng seed version shouldn't roll over a 32-bit counter "
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"for approximately 456,000 years"));
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atomic_store_rel_32(&fxrng_shpage_mapping->fx_generation32,
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(uint32_t)gen);
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}
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static void
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alloc_sv_fxrng_generation(void)
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{
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int base;
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/*
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* Allocate a full cache line for the fxrng root generation (64-bit
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* counter, or truncated 32-bit counter on ILP32 userspace). It is
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* important that the line is not shared with frequently dirtied data,
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* and the shared page allocator lacks a __read_mostly mechanism.
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* However, PAGE_SIZE is typically large relative to the amount of
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* stuff we've got in it so far, so maybe the possible waste isn't an
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* issue.
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*/
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base = shared_page_alloc(CACHE_LINE_SIZE, CACHE_LINE_SIZE);
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KASSERT(base != -1, ("%s: base allocation failed", __func__));
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fxrng_shpage_mapping = (void *)(shared_page_mapping + base);
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*fxrng_shpage_mapping = (struct vdso_fxrng_generation) {
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.fx_vdso_version = VDSO_FXRNG_VER_CURR,
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};
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}
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#endif /* RANDOM_FENESTRASX */
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void
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exec_sysvec_init(void *param)
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{
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struct sysentvec *sv;
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u_int flags;
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int res;
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sv = param;
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flags = sv->sv_flags;
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if ((flags & SV_SHP) == 0)
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return;
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MPASS(sv->sv_shared_page_obj == NULL);
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MPASS(sv->sv_shared_page_base != 0);
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sv->sv_shared_page_obj = shared_page_obj;
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if ((flags & SV_ABI_MASK) == SV_ABI_FREEBSD) {
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if ((flags & SV_DSO_SIG) != 0) {
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res = shared_page_fill((uintptr_t)sv->sv_szsigcode,
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16, sv->sv_sigcode);
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if (res == -1)
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panic("copying vdso to shared page");
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sv->sv_vdso_offset = res;
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sv->sv_sigcode_offset = res + sv->sv_sigcodeoff;
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} else {
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res = shared_page_fill(*(sv->sv_szsigcode),
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16, sv->sv_sigcode);
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if (res == -1)
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panic("copying sigtramp to shared page");
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sv->sv_sigcode_offset = res;
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}
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}
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if ((flags & SV_TIMEKEEP) != 0) {
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#ifdef COMPAT_FREEBSD32
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if ((flags & SV_ILP32) != 0) {
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if ((flags & SV_ABI_MASK) == SV_ABI_FREEBSD) {
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KASSERT(compat32_svtk == NULL,
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("Compat32 already registered"));
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compat32_svtk = alloc_sv_tk_compat32();
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} else {
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KASSERT(compat32_svtk != NULL,
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("Compat32 not registered"));
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}
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sv->sv_timekeep_offset = compat32_svtk->sv_timekeep_off;
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} else {
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#endif
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if ((flags & SV_ABI_MASK) == SV_ABI_FREEBSD) {
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KASSERT(host_svtk == NULL,
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("Host already registered"));
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host_svtk = alloc_sv_tk();
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} else {
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KASSERT(host_svtk != NULL,
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("Host not registered"));
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}
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sv->sv_timekeep_offset = host_svtk->sv_timekeep_off;
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#ifdef COMPAT_FREEBSD32
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}
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#endif
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}
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#ifdef RANDOM_FENESTRASX
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if ((flags & (SV_ABI_MASK | SV_RNG_SEED_VER)) ==
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(SV_ABI_FREEBSD | SV_RNG_SEED_VER)) {
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/*
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* Only allocate a single VDSO entry for multiple sysentvecs,
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* i.e., native and COMPAT32.
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*/
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if (fxrng_shpage_mapping == NULL)
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alloc_sv_fxrng_generation();
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sv->sv_fxrng_gen_offset =
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(char *)fxrng_shpage_mapping - shared_page_mapping;
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}
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#endif
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}
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void
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exec_sysvec_init_secondary(struct sysentvec *sv, struct sysentvec *sv2)
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{
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MPASS((sv2->sv_flags & SV_ABI_MASK) == (sv->sv_flags & SV_ABI_MASK));
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MPASS((sv2->sv_flags & SV_TIMEKEEP) == (sv->sv_flags & SV_TIMEKEEP));
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MPASS((sv2->sv_flags & SV_SHP) != 0 && (sv->sv_flags & SV_SHP) != 0);
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MPASS((sv2->sv_flags & SV_DSO_SIG) == (sv->sv_flags & SV_DSO_SIG));
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MPASS((sv2->sv_flags & SV_RNG_SEED_VER) ==
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(sv->sv_flags & SV_RNG_SEED_VER));
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sv2->sv_shared_page_obj = sv->sv_shared_page_obj;
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sv2->sv_sigcode_offset = sv->sv_sigcode_offset;
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sv2->sv_vdso_offset = sv->sv_vdso_offset;
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if ((sv2->sv_flags & SV_ABI_MASK) != SV_ABI_FREEBSD)
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return;
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sv2->sv_timekeep_offset = sv->sv_timekeep_offset;
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sv2->sv_fxrng_gen_offset = sv->sv_fxrng_gen_offset;
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}
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