freebsd-dev/sys/kern/kern_sharedpage.c

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/*-
* Copyright (c) 2010, 2012 Konstantin Belousov <kib@FreeBSD.org>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_compat.h"
#include "opt_vm.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sysent.h>
#include <sys/sysctl.h>
#include <sys/vdso.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
static struct sx shared_page_alloc_sx;
static vm_object_t shared_page_obj;
static int shared_page_free;
char *shared_page_mapping;
void
shared_page_write(int base, int size, const void *data)
{
bcopy(data, shared_page_mapping + base, size);
}
static int
shared_page_alloc_locked(int size, int align)
{
int res;
res = roundup(shared_page_free, align);
if (res + size >= IDX_TO_OFF(shared_page_obj->size))
res = -1;
else
shared_page_free = res + size;
return (res);
}
int
shared_page_alloc(int size, int align)
{
int res;
sx_xlock(&shared_page_alloc_sx);
res = shared_page_alloc_locked(size, align);
sx_xunlock(&shared_page_alloc_sx);
return (res);
}
int
shared_page_fill(int size, int align, const void *data)
{
int res;
sx_xlock(&shared_page_alloc_sx);
res = shared_page_alloc_locked(size, align);
if (res != -1)
shared_page_write(res, size, data);
sx_xunlock(&shared_page_alloc_sx);
return (res);
}
static void
shared_page_init(void *dummy __unused)
{
vm_page_t m;
vm_offset_t addr;
sx_init(&shared_page_alloc_sx, "shpsx");
shared_page_obj = vm_pager_allocate(OBJT_PHYS, 0, PAGE_SIZE,
VM_PROT_DEFAULT, 0, NULL);
VM_OBJECT_LOCK(shared_page_obj);
m = vm_page_grab(shared_page_obj, 0, VM_ALLOC_RETRY | VM_ALLOC_NOBUSY |
VM_ALLOC_ZERO);
m->valid = VM_PAGE_BITS_ALL;
VM_OBJECT_UNLOCK(shared_page_obj);
addr = kmem_alloc_nofault(kernel_map, PAGE_SIZE);
pmap_qenter(addr, &m, 1);
shared_page_mapping = (char *)addr;
}
SYSINIT(shp, SI_SUB_EXEC, SI_ORDER_FIRST, (sysinit_cfunc_t)shared_page_init,
NULL);
static void
timehands_update(struct sysentvec *sv)
{
struct vdso_timehands th;
struct vdso_timekeep *tk;
uint32_t enabled, idx;
enabled = tc_fill_vdso_timehands(&th);
tk = (struct vdso_timekeep *)(shared_page_mapping +
sv->sv_timekeep_off);
idx = sv->sv_timekeep_curr;
atomic_store_rel_32(&tk->tk_th[idx].th_gen, 0);
if (++idx >= VDSO_TH_NUM)
idx = 0;
sv->sv_timekeep_curr = idx;
if (++sv->sv_timekeep_gen == 0)
sv->sv_timekeep_gen = 1;
th.th_gen = 0;
if (enabled)
tk->tk_th[idx] = th;
tk->tk_enabled = enabled;
atomic_store_rel_32(&tk->tk_th[idx].th_gen, sv->sv_timekeep_gen);
tk->tk_current = idx;
}
#ifdef COMPAT_FREEBSD32
static void
timehands_update32(struct sysentvec *sv)
{
struct vdso_timekeep32 *tk;
struct vdso_timehands32 th;
uint32_t enabled, idx;
enabled = tc_fill_vdso_timehands32(&th);
tk = (struct vdso_timekeep32 *)(shared_page_mapping +
sv->sv_timekeep_off);
idx = sv->sv_timekeep_curr;
atomic_store_rel_32(&tk->tk_th[idx].th_gen, 0);
if (++idx >= VDSO_TH_NUM)
idx = 0;
sv->sv_timekeep_curr = idx;
if (++sv->sv_timekeep_gen == 0)
sv->sv_timekeep_gen = 1;
th.th_gen = 0;
if (enabled)
tk->tk_th[idx] = th;
tk->tk_enabled = enabled;
atomic_store_rel_32(&tk->tk_th[idx].th_gen, sv->sv_timekeep_gen);
tk->tk_current = idx;
}
#endif
/*
* This is hackish, but easiest way to avoid creating list structures
* that needs to be iterated over from the hardclock interrupt
* context.
*/
static struct sysentvec *host_sysentvec;
#ifdef COMPAT_FREEBSD32
static struct sysentvec *compat32_sysentvec;
#endif
void
timekeep_push_vdso(void)
{
if (host_sysentvec != NULL && host_sysentvec->sv_timekeep_base != 0)
timehands_update(host_sysentvec);
#ifdef COMPAT_FREEBSD32
if (compat32_sysentvec != NULL &&
compat32_sysentvec->sv_timekeep_base != 0)
timehands_update32(compat32_sysentvec);
#endif
}
void
exec_sysvec_init(void *param)
{
struct sysentvec *sv;
int tk_base;
uint32_t tk_ver;
sv = (struct sysentvec *)param;
if ((sv->sv_flags & SV_SHP) == 0)
return;
sv->sv_shared_page_obj = shared_page_obj;
sv->sv_sigcode_base = sv->sv_shared_page_base +
shared_page_fill(*(sv->sv_szsigcode), 16, sv->sv_sigcode);
if ((sv->sv_flags & SV_ABI_MASK) != SV_ABI_FREEBSD)
return;
tk_ver = VDSO_TK_VER_CURR;
#ifdef COMPAT_FREEBSD32
if ((sv->sv_flags & SV_ILP32) != 0) {
tk_base = shared_page_alloc(sizeof(struct vdso_timekeep32) +
sizeof(struct vdso_timehands32) * VDSO_TH_NUM, 16);
KASSERT(tk_base != -1, ("tk_base -1 for 32bit"));
shared_page_write(tk_base + offsetof(struct vdso_timekeep32,
tk_ver), sizeof(uint32_t), &tk_ver);
KASSERT(compat32_sysentvec == 0,
("Native compat32 already registered"));
compat32_sysentvec = sv;
} else {
#endif
tk_base = shared_page_alloc(sizeof(struct vdso_timekeep) +
sizeof(struct vdso_timehands) * VDSO_TH_NUM, 16);
KASSERT(tk_base != -1, ("tk_base -1 for native"));
shared_page_write(tk_base + offsetof(struct vdso_timekeep,
tk_ver), sizeof(uint32_t), &tk_ver);
KASSERT(host_sysentvec == 0, ("Native already registered"));
host_sysentvec = sv;
#ifdef COMPAT_FREEBSD32
}
#endif
sv->sv_timekeep_base = sv->sv_shared_page_base + tk_base;
sv->sv_timekeep_off = tk_base;
timekeep_push_vdso();
}