freebsd-skq/sys/powerpc/include/slb.h
Nathan Whitehorn 54c562081f Restructure the way the copyin/copyout segment is stored to prevent a
concurrency bug. Since all SLB/SR entries were invalidated during an
exception, a decrementer exception could cause the user segment to be
invalidated during a copyin()/copyout() without a thread switch that
would cause it to be restored from the PCB, potentially causing the
operation to continue on invalid memory. This is now handled by explicit
restoration of segment 12 from the PCB on 32-bit systems and a check in
the Data Segment Exception handler on 64-bit.

While here, cause copyin()/copyout() to check whether the requested
user segment is already installed, saving some pipeline flushes, and
fix the synchronization primitives around the mtsr and slbmte
instructions to prevent accessing stale segments.

MFC after:	2 weeks
2010-10-30 23:07:30 +00:00

78 lines
3.0 KiB
C

/*-
* Copyright (C) 2009 Nathan Whitehorn
* 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 ``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 TOOLS GMBH 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_SLB_H_
#define _MACHINE_SLB_H_
/*
* Bit definitions for segment lookaside buffer entries.
*
* PowerPC Microprocessor Family: The Programming Environments for 64-bit
* Microprocessors, section 7.4.2.1
*
* Note that these bitmasks are relative to the values for one of the two
* values for slbmte, slbmfee, and slbmfev, not the internal SLB
* representation.
*/
#define SLBV_KS 0x0000000000000800UL /* Supervisor-state prot key */
#define SLBV_KP 0x0000000000000400UL /* User-state prot key */
#define SLBV_N 0x0000000000000200UL /* No-execute protection */
#define SLBV_L 0x0000000000000100UL /* Large page selector */
#define SLBV_CLASS 0x0000000000000080UL /* Class selector */
#define SLBV_VSID_MASK 0xfffffffffffff000UL /* Virtual segment ID mask */
#define SLBV_VSID_SHIFT 12
/*
* Make a predictable 1:1 map from ESIDs to VSIDs for the kernel. Hash table
* coverage is increased by swizzling the ESID and multiplying by a prime
* number (0x13bb).
*/
#define KERNEL_VSID_BIT 0x0000001000000000UL /* Bit set in all kernel VSIDs */
#define KERNEL_VSID(esid) ((((((uint64_t)esid << 8) | ((uint64_t)esid >> 28)) \
* 0x13bbUL) & (KERNEL_VSID_BIT - 1)) | \
KERNEL_VSID_BIT)
#define SLBE_VALID 0x0000000008000000UL /* SLB entry valid */
#define SLBE_INDEX_MASK 0x0000000000000fffUL /* SLB index mask*/
#define SLBE_ESID_MASK 0xfffffffff0000000UL /* Effective segment ID mask */
#define SLBE_ESID_SHIFT 28
/*
* User segment for copyin/out
*/
#define USER_SLB_SLOT 63
#define USER_SLB_SLBE (((USER_ADDR >> ADDR_SR_SHFT) << SLBE_ESID_SHIFT) | \
SLBE_VALID | USER_SLB_SLOT)
struct slb {
uint64_t slbv;
uint64_t slbe;
};
#endif /* !_MACHINE_SLB_H_ */