freebsd-dev/sys/arm64/include/pte.h
Alan Cox 56e66ce802 Ordinarily, during a superpage promotion or demotion within a pmap, the
pmap's lock ensures that other operations on the pmap don't observe the
old mapping being broken before the new mapping is established.  However,
pmap_kextract() doesn't acquire the kernel pmap's lock, so it may observe
the broken mapping.  And, if it does, it returns an incorrect result.

This revision implements a lock-free solution to this problem in
pmap_update_entry() and pmap_kextract() because pmap_kextract() can't
acquire the kernel pmap's lock.

Reported by:	andrew, greg_unrelenting.technology
Reviewed by:	andrew, markj
Tested by:	greg_unrelenting.technology
X-MFC with:	r350579
Differential Revision:	https://reviews.freebsd.org/D21169
2019-08-08 06:26:34 +00:00

137 lines
4.5 KiB
C

/*-
* Copyright (c) 2014 Andrew Turner
* Copyright (c) 2014-2015 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Andrew Turner under
* sponsorship from the FreeBSD Foundation.
*
* 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.
*
* $FreeBSD$
*/
#ifndef _MACHINE_PTE_H_
#define _MACHINE_PTE_H_
#ifndef LOCORE
typedef uint64_t pd_entry_t; /* page directory entry */
typedef uint64_t pt_entry_t; /* page table entry */
#endif
/* Block and Page attributes */
#define ATTR_MASK_H UINT64_C(0xfffc000000000000)
#define ATTR_MASK_L UINT64_C(0x0000000000000fff)
#define ATTR_MASK (ATTR_MASK_H | ATTR_MASK_L)
/* Bits 58:55 are reserved for software */
#define ATTR_SW_UNUSED2 (1UL << 58)
#define ATTR_SW_UNUSED1 (1UL << 57)
#define ATTR_SW_MANAGED (1UL << 56)
#define ATTR_SW_WIRED (1UL << 55)
#define ATTR_UXN (1UL << 54)
#define ATTR_PXN (1UL << 53)
#define ATTR_XN (ATTR_PXN | ATTR_UXN)
#define ATTR_CONTIGUOUS (1UL << 52)
#define ATTR_DBM (1UL << 51)
#define ATTR_nG (1 << 11)
#define ATTR_AF (1 << 10)
#define ATTR_SH(x) ((x) << 8)
#define ATTR_SH_MASK ATTR_SH(3)
#define ATTR_SH_NS 0 /* Non-shareable */
#define ATTR_SH_OS 2 /* Outer-shareable */
#define ATTR_SH_IS 3 /* Inner-shareable */
#define ATTR_AP_RW_BIT (1 << 7)
#define ATTR_AP(x) ((x) << 6)
#define ATTR_AP_MASK ATTR_AP(3)
#define ATTR_AP_RW (0 << 1)
#define ATTR_AP_RO (1 << 1)
#define ATTR_AP_USER (1 << 0)
#define ATTR_NS (1 << 5)
#define ATTR_IDX(x) ((x) << 2)
#define ATTR_IDX_MASK (7 << 2)
#define ATTR_DEFAULT (ATTR_AF | ATTR_SH(ATTR_SH_IS))
#define ATTR_DESCR_MASK 3
#define ATTR_DESCR_VALID 1
#define ATTR_DESCR_TYPE_MASK 2
#define ATTR_DESCR_TYPE_TABLE 2
#define ATTR_DESCR_TYPE_PAGE 2
#define ATTR_DESCR_TYPE_BLOCK 0
/* Level 0 table, 512GiB per entry */
#define L0_SHIFT 39
#define L0_SIZE (1ul << L0_SHIFT)
#define L0_OFFSET (L0_SIZE - 1ul)
#define L0_INVAL 0x0 /* An invalid address */
/* 0x1 Level 0 doesn't support block translation */
/* 0x2 also marks an invalid address */
#define L0_TABLE 0x3 /* A next-level table */
/* Level 1 table, 1GiB per entry */
#define L1_SHIFT 30
#define L1_SIZE (1 << L1_SHIFT)
#define L1_OFFSET (L1_SIZE - 1)
#define L1_INVAL L0_INVAL
#define L1_BLOCK 0x1
#define L1_TABLE L0_TABLE
/* Level 2 table, 2MiB per entry */
#define L2_SHIFT 21
#define L2_SIZE (1 << L2_SHIFT)
#define L2_OFFSET (L2_SIZE - 1)
#define L2_INVAL L1_INVAL
#define L2_BLOCK L1_BLOCK
#define L2_TABLE L1_TABLE
#define L2_BLOCK_MASK UINT64_C(0xffffffe00000)
/* Level 3 table, 4KiB per entry */
#define L3_SHIFT 12
#define L3_SIZE (1 << L3_SHIFT)
#define L3_OFFSET (L3_SIZE - 1)
#define L3_SHIFT 12
#define L3_INVAL 0x0
/* 0x1 is reserved */
/* 0x2 also marks an invalid address */
#define L3_PAGE 0x3
#define PMAP_MAPDEV_EARLY_SIZE (L2_SIZE * 8)
#define L0_ENTRIES_SHIFT 9
#define L0_ENTRIES (1 << L0_ENTRIES_SHIFT)
#define L0_ADDR_MASK (L0_ENTRIES - 1)
#define Ln_ENTRIES_SHIFT 9
#define Ln_ENTRIES (1 << Ln_ENTRIES_SHIFT)
#define Ln_ADDR_MASK (Ln_ENTRIES - 1)
#define Ln_TABLE_MASK ((1 << 12) - 1)
#define pmap_l0_index(va) (((va) >> L0_SHIFT) & L0_ADDR_MASK)
#define pmap_l1_index(va) (((va) >> L1_SHIFT) & Ln_ADDR_MASK)
#define pmap_l2_index(va) (((va) >> L2_SHIFT) & Ln_ADDR_MASK)
#define pmap_l3_index(va) (((va) >> L3_SHIFT) & Ln_ADDR_MASK)
#endif /* !_MACHINE_PTE_H_ */
/* End of pte.h */