[apple/xnu.git] / osfmk / ppc / atomic_switch.s

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
#include	<ppc/asm.h>
#include	<ppc/proc_reg.h>
#include	<ppc/exception.h>
#include	<mach/ppc/vm_param.h>
#include	<assym.s>

/*
 *	Classic atomic switch and fast trap code
 *	Written by: Mark Gorlinsky
 */

/*
**
** Blue Box Fast Trap entry
**
**
** The registers at entry are as hw_exceptions left them. Which means
** that the Blue Box data area is pointed to be R26.
**
** We exit here through the fast path exit point in hw_exceptions.  That means that
** upon exit, R4 must not change.  It is the savearea with the current user context
** to restore.
**
** Input registers are:
** r0  = Syscall number
** r4  = Current context savearea (do not modify)
** r13 = THREAD_TOP_ACT pointer
** r26 = base of ACT_MACH_BDA in kernel address space
** -- for Traps --
** r24 = Index into TWI table (x4)
**
**
*/


ENTRY(atomic_switch_syscall, TAG_NO_FRAME_USED)
	
/*
 *			Note: the BlueBox fast path system calls (-1 and -2) we handled as
 *			an ultra-fast trap in lowmem_vectors.
 */
			lwz		r5,bbSysCall(r13)					; Pick up the syscall vector
			b		.L_CallPseudoKernel

ENTRY(atomic_switch_trap, TAG_NO_FRAME_USED)

/*
** functions 0-15 -> Call PseudoKernel
**             16 -> Exit PseudoKernel
*/

			cmplwi	cr7,r24,BB_RFI_TRAP					; Is this an RFI?
			beq		cr7,.L_ExitPseudoKernel				; Yes...

			lwz		r5,bbTrap(r13)						; Pick up the trap vector

/******************************************************************************
 * void CallPseudoKernel ( int vector, thread_act_t * act, BEDA_t * beda, savearea *sv )
 *
 * This op provides a means of invoking the BlueBox PseudoKernel from a
 * system (68k) or native (PPC) context while changing BlueBox interruption
 * state atomically.  As an added bonus, this op leaves all but R1/PC of the user 
 * state registers intact.  R1/PC are saved in a per thread save area, the base of
 * which is located in the bbDescAddr member of the thread_act structure.
 *
 * This op is invoked from the Emulator Trap dispatch table or from a System
 * Call when Mach SCs have been disabled. A vectorindex is passed in to indicate
 * which vector should be taken.
 *
 * If this op is invoked from the Emulator Trap dispatch table, the kernel is
 * aware of starting address of this table.  It used the users PC (SRR0) 
 * and the start of the Trap dispatch table address to verify the trap exception 
 * as a atomic_switch trap.  If a trap exception is verified as a atomic_switch
 * trap we enter here with the following registers loaded.
 *
 * Input registers are:
 * r5	= Vector to take
 * r13 	= Current thread context data
 * r26	= Base address of BlueBox exception data area in kernel address space
 * r4	= Current context savearea (do not modify)
 *
 ******************************************************************************/

.L_CallPseudoKernel:

			mfsprg	r2,1								; Get the current activation
			lwz		r2,ACT_PER_PROC(r2)					; Get the per_proc block
			rlwinm	r6,r26,0,0,19						; Start of page is bttd
			lwz		r7,ACT_MACT_SPF(r13)				; Get special flags 
			lwz		r1,BTTD_INTERRUPT_VECTOR(r6)		; Get interrupt vector
			rlwinm	r7,r7,0,bbNoMachSCbit+1,bbNoMachSCbit-1	
														; Reactivate Mach SCs
			lwz		r8,BTTD_INTCONTROLWORD(r6)			; Get Interrupt Control Word
			cmpwi	r1,0								; Is this a preemptive thread ?
			stw		r7,ACT_MACT_SPF(r13)				; Update special flags
			stw		r7,spcFlags(r2)						; Update per_proc version
			beq		.L_CallFromPreemptiveThread			; No int vector means preemptive thread

			rlwinm	r1,r8,0,INTSTATEMASK_B,INTSTATEMASK_E
														; Extract current Interrupt state
			rlwinm	r8,r8,0,INTSTATEMASK_E+1,INTSTATEMASK_B-1
														; Clear current interrupt state
			xoris	r2,r1,SYSCONTEXTSTATE				; Setup for System Context check 
			lwz		r1,savecr(r4)						; Load current CR bits
			cmpwi	r2,0								; Check if state is System Context?
			oris	r8,r8,PSEUDOKERNELSTATE				; Update state for entering the PK
			bne		.L_CallFromAlternateContext			; No, then do not save CR2 bits

			rlwimi	r8,r1,32-INTCR2TOBACKUPSHIFT,INTBACKUPCR2MASK_B,INTBACKUPCR2MASK_E
														; Insert live CR2 in ICW BackupCR2
.L_CallFromAlternateContext:

			stw		r8,BTTD_INTCONTROLWORD(r6)			; Update ICW

.L_CallFromPreemptiveThread:

			lwz		r1,savesrr0+4(r4)					; Get current PC
			lwz		r2,saver1+4(r4)						; Get current R1
			lwz		r3,savesrr1+4(r4)					; Get current MSR
			stw		r1,BEDA_SRR0(r26)					; Save current PC
			rlwinm	r3,r3,0,MSR_BE_BIT+1,MSR_SE_BIT-1				
														; Clear SE|BE bits in MSR
			stw		r2,BEDA_SPRG1(r26)					; Save current R1 
			stw		r3,savesrr1+4(r4)					; Load new MSR

			lwz		r1,BEDA_SPRG0(r26)					; Get replacement R1
			stw		r5,savesrr0+4(r4)					; Save vector as PC
			stw		r3,BEDA_SRR1(r26)					; Update saved MSR
			stw		r1,saver1+4(r4)						; Load up new R1

			b		EXT(fastexit)						; Go back and take the fast path exit...

/******************************************************************************
 * void ExitPseudoKernel ( thread_act_t * act, BEDA_t * beda, savearea * sv  )
 *
 * This op provides a means of exiting from the BlueBox PseudoKernel to a
 * user context.  This op attempts to simulate an RFI for the returning
 * Traps (atomic_switch_trap) and SysCalls (atomic_switch_syscall).  Only the
 * Blue Thread handling interrupts is allowed to atomically change
 * interruption state and handle pending interrupts.
 *
 * If an interrupt is pending and we are returning to the alternate context,
 * the exit is aborted and we return to an pending interrupt handler in the
 * Blue Box pseudokernel.  
 *
 * It also allows the MSR's FE0, FE1, BE and SE bits to updated for the user
 * and completes the PPC register loading.
 *
 * Input registers are:
 * r4  = Current context savearea (do not modify)
 * r13 = Pointer to the current active thread's data
 * r26 = Base address of BlueBox Data in kernel address space 
 *
 ******************************************************************************/

.L_ExitPseudoKernel:

			rlwinm	r6,r26,0,0,19						; Start of page is bttd
			lwz		r7,ACT_MACT_SPF(r13)				; Get special flags
			lwz		r2,BTTD_INTERRUPT_VECTOR(r6)		; Get the interrupt vector
			lwz		r1,BEDA_SPRG1(r26)					; Get saved CTR
			ori		r7,r7,(0x8000 >> (bbNoMachSCbit - 16))	; Disable Mach SCs for Blue Box

			cmpwi	r2,0								; Is this a preemptive thread
			stw		r1,savectr+4(r4)					; Update CTR
			beq		.L_ExitFromPreemptiveThread

			lwz		r8,BTTD_INTCONTROLWORD(r6)			; Get ICW
			lwz		r1,BTTD_NEWEXITSTATE(r6)			; New interrupt state
			lwz		r2,BTTD_TESTINTMASK(r6)				; Get pending interrupt mask
			lis		r3,SYSCONTEXTSTATE					; Setup for check in system context
			rlwimi	r8,r1,0,INTSTATEMASK_B,INTSTATEMASK_E
														; Insert new state
			cmplw	cr1,r1,r3							; System context ?
			and.	r2,r8,r2							; Any pending interrupt?
			lwz		r1,savecr(r4)						; Get current CR
			
			beq		cr1,.L_ExitToSystemContext			; We are in system context
			beq		.L_ExitUpdateRuptControlWord		; We do not have a pending interrupt

			lwz		r2,saver1+4(r4)						; Get current R1
			lwz		r1,BEDA_SPRG0(r26)					; Get replacement R1
			stw		r2,BEDA_SPRG1(r26)					; Save current R1
			stw		r1,saver1+4(r4)						; Load up new R1
			lwz		r3,bbPending(r13)					; Get pending interrupt PC
			b		.L_ExitAbortExit					; Abort and Exit

.L_ExitToSystemContext:
			rlwimi	r1,r8,INTCR2TOBACKUPSHIFT,INTCR2MASK_B,INTCR2MASK_E
														; Insert live CR2 into backup CR2
.L_ExitUpdateRuptControlWord:
			stw		r8,BTTD_INTCONTROLWORD(r6)			; Update ICW
			stw		r1,savecr(r4)						; Update CR

.L_ExitFromPreemptiveThread:
			mfsprg	r3,1								; Get the current activation
			lwz		r3,ACT_PER_PROC(r3)					; Get the per_proc block
			lwz		r2,savesrr1+4(r4)					; Get current MSR	
			lwz		r1,BEDA_SRR1(r26)					; Get new MSR
			stw		r7,ACT_MACT_SPF(r13)				; Update special flags
			stw		r7,spcFlags(r3)						; Update per_proc version
			rlwimi	r2,r1,0,MSR_FE0_BIT,MSR_FE1_BIT
														; Insert FE0,FE1,SE,BE bits
			lwz		r3,BEDA_SRR0(r26)					; Get new PC
			stw		r2,savesrr1+4(r4)					; Update MSR

.L_ExitAbortExit:
			stw		r3,savesrr0+4(r4)					; Update PC

			b		EXT(fastexit)						; Go back and take the fast path exit...
Commit	Line	Data
1c79356b A	1	/*
	2	* Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
e5568f75 A	6	* The contents of this file constitute Original Code as defined in and
	7	* are subject to the Apple Public Source License Version 1.1 (the
	8	* "License"). You may not use this file except in compliance with the
	9	* License. Please obtain a copy of the License at
	10	* http://www.apple.com/publicsource and read it before using this file.
1c79356b	11	*
e5568f75 A	12	* This Original Code and all software distributed under the License are
e5568f75 A	13	* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
1c79356b A	14	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
1c79356b A	15	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
e5568f75 A	16	* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
	17	* License for the specific language governing rights and limitations
	18	* under the License.
1c79356b A	19	*
	20	* @APPLE_LICENSE_HEADER_END@
	21	*/
	22	#include <ppc/asm.h>
	23	#include <ppc/proc_reg.h>
	24	#include <ppc/exception.h>
	25	#include <mach/ppc/vm_param.h>
	26	#include <assym.s>
	27
	28	/*
	29	* Classic atomic switch and fast trap code
	30	* Written by: Mark Gorlinsky
	31	*/
	32
	33	/*
	34	**
	35	** Blue Box Fast Trap entry
	36	**
	37	**
	38	** The registers at entry are as hw_exceptions left them. Which means
	39	** that the Blue Box data area is pointed to be R26.
	40	**
	41	** We exit here through the fast path exit point in hw_exceptions. That means that
	42	** upon exit, R4 must not change. It is the savearea with the current user context
	43	** to restore.
	44	**
	45	** Input registers are:
	46	** r0 = Syscall number
	47	** r4 = Current context savearea (do not modify)
	48	** r13 = THREAD_TOP_ACT pointer
	49	** r26 = base of ACT_MACH_BDA in kernel address space
	50	** -- for Traps --
	51	** r24 = Index into TWI table (x4)
	52	**
	53	**
	54	*/
	55
	56
	57	ENTRY(atomic_switch_syscall, TAG_NO_FRAME_USED)
	58
	59	/*
0b4e3aa0 A	60	* Note: the BlueBox fast path system calls (-1 and -2) we handled as
0b4e3aa0 A	61	* an ultra-fast trap in lowmem_vectors.
1c79356b	62	*/
55e303ae	63	lwz r5,bbSysCall(r13) ; Pick up the syscall vector
1c79356b A	64	b .L_CallPseudoKernel
	65
	66	ENTRY(atomic_switch_trap, TAG_NO_FRAME_USED)
	67
	68	/*
	69	** functions 0-15 -> Call PseudoKernel
	70	** 16 -> Exit PseudoKernel
	71	*/
	72
	73	cmplwi cr7,r24,BB_RFI_TRAP ; Is this an RFI?
	74	beq cr7,.L_ExitPseudoKernel ; Yes...
	75
55e303ae	76	lwz r5,bbTrap(r13) ; Pick up the trap vector
1c79356b A	77
	78	/******************************************************************************
	79	* void CallPseudoKernel ( int vector, thread_act_t * act, BEDA_t * beda, savearea *sv )
	80	*
	81	* This op provides a means of invoking the BlueBox PseudoKernel from a
	82	* system (68k) or native (PPC) context while changing BlueBox interruption
	83	* state atomically. As an added bonus, this op leaves all but R1/PC of the user
	84	* state registers intact. R1/PC are saved in a per thread save area, the base of
	85	* which is located in the bbDescAddr member of the thread_act structure.
	86	*
	87	* This op is invoked from the Emulator Trap dispatch table or from a System
	88	* Call when Mach SCs have been disabled. A vectorindex is passed in to indicate
	89	* which vector should be taken.
	90	*
	91	* If this op is invoked from the Emulator Trap dispatch table, the kernel is
	92	* aware of starting address of this table. It used the users PC (SRR0)
	93	* and the start of the Trap dispatch table address to verify the trap exception
	94	* as a atomic_switch trap. If a trap exception is verified as a atomic_switch
	95	* trap we enter here with the following registers loaded.
	96	*
	97	* Input registers are:
	98	* r5 = Vector to take
	99	* r13 = Current thread context data
	100	* r26 = Base address of BlueBox exception data area in kernel address space
	101	* r4 = Current context savearea (do not modify)
	102	*
	103	******************************************************************************/
	104
	105	.L_CallPseudoKernel:
	106
91447636 A	107	mfsprg r2,1 ; Get the current activation
91447636 A	108	lwz r2,ACT_PER_PROC(r2) ; Get the per_proc block
1c79356b A	109	rlwinm r6,r26,0,0,19 ; Start of page is bttd
	110	lwz r7,ACT_MACT_SPF(r13) ; Get special flags
	111	lwz r1,BTTD_INTERRUPT_VECTOR(r6) ; Get interrupt vector
	112	rlwinm r7,r7,0,bbNoMachSCbit+1,bbNoMachSCbit-1
	113	; Reactivate Mach SCs
	114	lwz r8,BTTD_INTCONTROLWORD(r6) ; Get Interrupt Control Word
	115	cmpwi r1,0 ; Is this a preemptive thread ?
	116	stw r7,ACT_MACT_SPF(r13) ; Update special flags
0b4e3aa0	117	stw r7,spcFlags(r2) ; Update per_proc version
1c79356b A	118	beq .L_CallFromPreemptiveThread ; No int vector means preemptive thread
	119
	120	rlwinm r1,r8,0,INTSTATEMASK_B,INTSTATEMASK_E
	121	; Extract current Interrupt state
	122	rlwinm r8,r8,0,INTSTATEMASK_E+1,INTSTATEMASK_B-1
	123	; Clear current interrupt state
	124	xoris r2,r1,SYSCONTEXTSTATE ; Setup for System Context check
	125	lwz r1,savecr(r4) ; Load current CR bits
	126	cmpwi r2,0 ; Check if state is System Context?
	127	oris r8,r8,PSEUDOKERNELSTATE ; Update state for entering the PK
	128	bne .L_CallFromAlternateContext ; No, then do not save CR2 bits
	129
	130	rlwimi r8,r1,32-INTCR2TOBACKUPSHIFT,INTBACKUPCR2MASK_B,INTBACKUPCR2MASK_E
	131	; Insert live CR2 in ICW BackupCR2
	132	.L_CallFromAlternateContext:
	133
	134	stw r8,BTTD_INTCONTROLWORD(r6) ; Update ICW
	135
	136	.L_CallFromPreemptiveThread:
	137
55e303ae A	138	lwz r1,savesrr0+4(r4) ; Get current PC
	139	lwz r2,saver1+4(r4) ; Get current R1
	140	lwz r3,savesrr1+4(r4) ; Get current MSR
1c79356b A	141	stw r1,BEDA_SRR0(r26) ; Save current PC
	142	rlwinm r3,r3,0,MSR_BE_BIT+1,MSR_SE_BIT-1
	143	; Clear SE\|BE bits in MSR
	144	stw r2,BEDA_SPRG1(r26) ; Save current R1
55e303ae	145	stw r3,savesrr1+4(r4) ; Load new MSR
1c79356b A	146
1c79356b A	147	lwz r1,BEDA_SPRG0(r26) ; Get replacement R1
55e303ae	148	stw r5,savesrr0+4(r4) ; Save vector as PC
1c79356b	149	stw r3,BEDA_SRR1(r26) ; Update saved MSR
55e303ae	150	stw r1,saver1+4(r4) ; Load up new R1
1c79356b A	151
	152	b EXT(fastexit) ; Go back and take the fast path exit...
	153
	154	/******************************************************************************
	155	* void ExitPseudoKernel ( thread_act_t * act, BEDA_t * beda, savearea * sv )
	156	*
	157	* This op provides a means of exiting from the BlueBox PseudoKernel to a
	158	* user context. This op attempts to simulate an RFI for the returning
	159	* Traps (atomic_switch_trap) and SysCalls (atomic_switch_syscall). Only the
	160	* Blue Thread handling interrupts is allowed to atomically change
	161	* interruption state and handle pending interrupts.
	162	*
	163	* If an interrupt is pending and we are returning to the alternate context,
	164	* the exit is aborted and we return to an pending interrupt handler in the
	165	* Blue Box pseudokernel.
	166	*
	167	* It also allows the MSR's FE0, FE1, BE and SE bits to updated for the user
	168	* and completes the PPC register loading.
	169	*
	170	* Input registers are:
	171	* r4 = Current context savearea (do not modify)
	172	* r13 = Pointer to the current active thread's data
	173	* r26 = Base address of BlueBox Data in kernel address space
	174	*
	175	******************************************************************************/
	176
	177	.L_ExitPseudoKernel:
	178
	179	rlwinm r6,r26,0,0,19 ; Start of page is bttd
	180	lwz r7,ACT_MACT_SPF(r13) ; Get special flags
	181	lwz r2,BTTD_INTERRUPT_VECTOR(r6) ; Get the interrupt vector
	182	lwz r1,BEDA_SPRG1(r26) ; Get saved CTR
0b4e3aa0	183	ori r7,r7,(0x8000 >> (bbNoMachSCbit - 16)) ; Disable Mach SCs for Blue Box
1c79356b A	184
1c79356b A	185	cmpwi r2,0 ; Is this a preemptive thread
55e303ae	186	stw r1,savectr+4(r4) ; Update CTR
1c79356b A	187	beq .L_ExitFromPreemptiveThread
	188
	189	lwz r8,BTTD_INTCONTROLWORD(r6) ; Get ICW
	190	lwz r1,BTTD_NEWEXITSTATE(r6) ; New interrupt state
	191	lwz r2,BTTD_TESTINTMASK(r6) ; Get pending interrupt mask
	192	lis r3,SYSCONTEXTSTATE ; Setup for check in system context
	193	rlwimi r8,r1,0,INTSTATEMASK_B,INTSTATEMASK_E
	194	; Insert new state
	195	cmplw cr1,r1,r3 ; System context ?
	196	and. r2,r8,r2 ; Any pending interrupt?
	197	lwz r1,savecr(r4) ; Get current CR
	198
	199	beq cr1,.L_ExitToSystemContext ; We are in system context
	200	beq .L_ExitUpdateRuptControlWord ; We do not have a pending interrupt
	201
55e303ae	202	lwz r2,saver1+4(r4) ; Get current R1
1c79356b A	203	lwz r1,BEDA_SPRG0(r26) ; Get replacement R1
1c79356b A	204	stw r2,BEDA_SPRG1(r26) ; Save current R1
55e303ae A	205	stw r1,saver1+4(r4) ; Load up new R1
55e303ae A	206	lwz r3,bbPending(r13) ; Get pending interrupt PC
1c79356b A	207	b .L_ExitAbortExit ; Abort and Exit
	208
	209	.L_ExitToSystemContext:
	210	rlwimi r1,r8,INTCR2TOBACKUPSHIFT,INTCR2MASK_B,INTCR2MASK_E
	211	; Insert live CR2 into backup CR2
	212	.L_ExitUpdateRuptControlWord:
	213	stw r8,BTTD_INTCONTROLWORD(r6) ; Update ICW
	214	stw r1,savecr(r4) ; Update CR
	215
	216	.L_ExitFromPreemptiveThread:
91447636 A	217	mfsprg r3,1 ; Get the current activation
91447636 A	218	lwz r3,ACT_PER_PROC(r3) ; Get the per_proc block
55e303ae	219	lwz r2,savesrr1+4(r4) ; Get current MSR
1c79356b A	220	lwz r1,BEDA_SRR1(r26) ; Get new MSR
1c79356b A	221	stw r7,ACT_MACT_SPF(r13) ; Update special flags
0b4e3aa0	222	stw r7,spcFlags(r3) ; Update per_proc version
1c79356b A	223	rlwimi r2,r1,0,MSR_FE0_BIT,MSR_FE1_BIT
	224	; Insert FE0,FE1,SE,BE bits
	225	lwz r3,BEDA_SRR0(r26) ; Get new PC
55e303ae	226	stw r2,savesrr1+4(r4) ; Update MSR
1c79356b A	227
1c79356b A	228	.L_ExitAbortExit:
55e303ae	229	stw r3,savesrr0+4(r4) ; Update PC
1c79356b A	230
	231	b EXT(fastexit) ; Go back and take the fast path exit...
	232