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freebsd-skq/sys/sparc64/include/wstate.h

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Implement a slightly different window spill/fill algorithm for dealing with user windows in kernel mode. We split the windows using %otherwin, but instead of spilling user window directly to the pcb, we attempt to spill to user space. If this fails because a stack page is not resident (or the stack is smashed), the fault handler at tl 2 will detect the situation and resume at tl 1 again where recovery code can spill to the pcb. Any windows that have been saved to the pcb will be copied out to the user stack on return from kernel mode. Add a first stab at 32 bit window handling. This uses much of the same recovery code as above because the alignment of the stack pointer is used to detect 32 bit code. Attempting to spill a 32 bit window to a 64 bit stack, or vice versa, will cause an alignment fault. The recovery code then changes the window state to vector to a 32 bit spill/fill handler and retries the faulting instruction. Add ktr traces in useful places during trap processing. Adjust comments to reflect new code and add many more.
2001-09-03 23:10:45 +00:00
/*-
* Copyright (c) 1997 Berkeley Software Design, Inc. 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.
* 3. Berkeley Software Design Inc's name may not be used to endorse or
* promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``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 BERKELEY SOFTWARE DESIGN INC 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.
*
* from: BSDI: wstate.h,v 1.4 1997/09/18 13:05:51 torek Exp
* $FreeBSD$
*/
#ifndef _MACHINE_WSTATE_H_
#define _MACHINE_WSTATE_H_
/*
- The firmware of Sun Fire V1280 has a misfeature of setting %wstate to 7 which corresponds to WSTATE_KMIX in OpenSolaris whenever calling into it which totally screws us even when restoring %wstate afterwards as spill/fill traps can happen while in OFW. The rather hackish OpenBSD approach of just setting the equivalent of WSTATE_KERNEL to 7 also is no option as we treat %wstate as a bit field. So in order to deal with this problem actually implement spill/fill handlers for %wstate 7 which just act as the WSTATE_KERNEL ones except of theoretically also handling 32-bit, turn off interrupts completely so we don't even take IPIs while in OFW which should ensure we only take spill/fill traps at most and restore %wstate after calling into OFW once we have taken over the trap table. While at it, actually set WSTATE_{,PROM}_KMIX before calling into OFW just like OpenSolaris does, which should at least help testing this change on non-V1280. - Remove comments referring to the %wstate usage in BSD/OS. - Remove the no longer used RSF_ALIGN_RETRY macro. - Correct some trap table addresses in comments. - Ensure %wstate is set to WSTATE_KERNEL when taking over the trap table. - Ensure PSTATE_AM is off when entering or exiting to OFW as well as that interrupts are also completely off when exiting to OFW as the firmware trap table shouldn't be used to handle our interrupts.
2010-03-21 13:09:54 +00:00
* Window state register bits
Implement a slightly different window spill/fill algorithm for dealing with user windows in kernel mode. We split the windows using %otherwin, but instead of spilling user window directly to the pcb, we attempt to spill to user space. If this fails because a stack page is not resident (or the stack is smashed), the fault handler at tl 2 will detect the situation and resume at tl 1 again where recovery code can spill to the pcb. Any windows that have been saved to the pcb will be copied out to the user stack on return from kernel mode. Add a first stab at 32 bit window handling. This uses much of the same recovery code as above because the alignment of the stack pointer is used to detect 32 bit code. Attempting to spill a 32 bit window to a 64 bit stack, or vice versa, will cause an alignment fault. The recovery code then changes the window state to vector to a 32 bit spill/fill handler and retries the faulting instruction. Add ktr traces in useful places during trap processing. Adjust comments to reflect new code and add many more.
2001-09-03 23:10:45 +00:00
*
* There really are no bits per se, just the two fields WSTATE.NORMAL
* and WSTATE.OTHER. The rest is up to software.
*
* We use WSTATE_NORMAL to represent user mode or kernel mode saves
* (whichever is currently in effect) and WSTATE_OTHER to represent
* user mode saves (only).
*
* Note that locore.s assumes this same bit layout (since the translation
* from "bits" to "{spill,fill}_N_{normal,other}" is done in hardware).
*/
Implement a nested window state. This avoids attempting to spill a user window to the user stack while in a nested kernel trap. We do this for entry to the kernel from user mode, but if we get an interrupt in kernel mode while there are still user windows in the cpu, and we attempt to spill to the user stack, we may take too many nested traps and overflow the trap stack, causing a red state exception. This is needed by upcoming changes to allow the user tsb to not be locked in the tlb. Reviewed by: tmm
2002-02-25 18:37:17 +00:00
#define WSTATE_NORMAL_MASK 1 /* wstate normal minus transition */
Rename definitions to better match the hardware wstate fields. Don't include WSTATE_TRANSITION in WSTATE_NORMAL_MASK.
2001-12-29 07:12:30 +00:00
#define WSTATE_OTHER_SHIFT 3 /* for wstate other / user */
Implement a nested window state. This avoids attempting to spill a user window to the user stack while in a nested kernel trap. We do this for entry to the kernel from user mode, but if we get an interrupt in kernel mode while there are still user windows in the cpu, and we attempt to spill to the user stack, we may take too many nested traps and overflow the trap stack, causing a red state exception. This is needed by upcoming changes to allow the user tsb to not be locked in the tlb. Reviewed by: tmm
2002-02-25 18:37:17 +00:00
#define WSTATE_OTHER_MASK /* wstate other minus nested */ \
(WSTATE_NORMAL_MASK << WSTATE_OTHER_SHIFT)
Implement a slightly different window spill/fill algorithm for dealing with user windows in kernel mode. We split the windows using %otherwin, but instead of spilling user window directly to the pcb, we attempt to spill to user space. If this fails because a stack page is not resident (or the stack is smashed), the fault handler at tl 2 will detect the situation and resume at tl 1 again where recovery code can spill to the pcb. Any windows that have been saved to the pcb will be copied out to the user stack on return from kernel mode. Add a first stab at 32 bit window handling. This uses much of the same recovery code as above because the alignment of the stack pointer is used to detect 32 bit code. Attempting to spill a 32 bit window to a 64 bit stack, or vice versa, will cause an alignment fault. The recovery code then changes the window state to vector to a 32 bit spill/fill handler and retries the faulting instruction. Add ktr traces in useful places during trap processing. Adjust comments to reflect new code and add many more.
2001-09-03 23:10:45 +00:00
Add a definition for normal kernel window state.
2001-10-20 17:08:33 +00:00
#define WSTATE_KERNEL 0 /* normal kernel wstate */
Implement a nested window state. This avoids attempting to spill a user window to the user stack while in a nested kernel trap. We do this for entry to the kernel from user mode, but if we get an interrupt in kernel mode while there are still user windows in the cpu, and we attempt to spill to the user stack, we may take too many nested traps and overflow the trap stack, causing a red state exception. This is needed by upcoming changes to allow the user tsb to not be locked in the tlb. Reviewed by: tmm
2002-02-25 18:37:17 +00:00
#define WSTATE_USER_64 0 /* normal 64bit user wstate */
#define WSTATE_USER_32 1 /* normal 32bit user wstate */
#define WSTATE_TRANSITION 2 /* if set, force user window */
#define WSTATE_NESTED /* if set, spill must not fault */ \
(WSTATE_TRANSITION << WSTATE_OTHER_SHIFT)
Add a definition for normal kernel window state.
2001-10-20 17:08:33 +00:00
- The firmware of Sun Fire V1280 has a misfeature of setting %wstate to 7 which corresponds to WSTATE_KMIX in OpenSolaris whenever calling into it which totally screws us even when restoring %wstate afterwards as spill/fill traps can happen while in OFW. The rather hackish OpenBSD approach of just setting the equivalent of WSTATE_KERNEL to 7 also is no option as we treat %wstate as a bit field. So in order to deal with this problem actually implement spill/fill handlers for %wstate 7 which just act as the WSTATE_KERNEL ones except of theoretically also handling 32-bit, turn off interrupts completely so we don't even take IPIs while in OFW which should ensure we only take spill/fill traps at most and restore %wstate after calling into OFW once we have taken over the trap table. While at it, actually set WSTATE_{,PROM}_KMIX before calling into OFW just like OpenSolaris does, which should at least help testing this change on non-V1280. - Remove comments referring to the %wstate usage in BSD/OS. - Remove the no longer used RSF_ALIGN_RETRY macro. - Correct some trap table addresses in comments. - Ensure %wstate is set to WSTATE_KERNEL when taking over the trap table. - Ensure PSTATE_AM is off when entering or exiting to OFW as well as that interrupts are also completely off when exiting to OFW as the firmware trap table shouldn't be used to handle our interrupts.
2010-03-21 13:09:54 +00:00
/* Values used by the PROM and (Open)Solaris */
#define WSTATE_PROM_KMIX 7
#define WSTATE_PROM_MASK 7
Implement a slightly different window spill/fill algorithm for dealing with user windows in kernel mode. We split the windows using %otherwin, but instead of spilling user window directly to the pcb, we attempt to spill to user space. If this fails because a stack page is not resident (or the stack is smashed), the fault handler at tl 2 will detect the situation and resume at tl 1 again where recovery code can spill to the pcb. Any windows that have been saved to the pcb will be copied out to the user stack on return from kernel mode. Add a first stab at 32 bit window handling. This uses much of the same recovery code as above because the alignment of the stack pointer is used to detect 32 bit code. Attempting to spill a 32 bit window to a 64 bit stack, or vice versa, will cause an alignment fault. The recovery code then changes the window state to vector to a 32 bit spill/fill handler and retries the faulting instruction. Add ktr traces in useful places during trap processing. Adjust comments to reflect new code and add many more.
2001-09-03 23:10:45 +00:00
#endif /* !_MACHINE_WSTATE_H_ */
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