// Copyright (c) 1997-2009 Nokia Corporation and/or its subsidiary(-ies).
// All rights reserved.
// This component and the accompanying materials are made available
// under the terms of the License "Eclipse Public License v1.0"
// which accompanies this distribution, and is available
// at the URL "http://www.eclipse.org/legal/epl-v10.html".
//
// Initial Contributors:
// Nokia Corporation - initial contribution.
//
// Contributors:
//
// Description:
//
#define INCLUDED_FROM_ASM

#include <e32cia.h>
#include <arm_mem.h>
#include "nk_cpu.h"
#include "xdefs.h"
#include "cache_maintenance.h"

#define iMState		iWaitLink.iSpare1

//#define __DEBUG_BAD_ADDR

#ifdef __REQUEST_COMPLETE_MACHINE_CODED__
#if defined(_DEBUG)
extern "C" void __DebugMsgRequestComplete(TInt a0, TInt a1, TInt a2);
extern "C" void __DebugMsgReqCompleteWrite(TInt a0, TInt a1, TInt a2);
#endif

__NAKED__ void DoRequestComplete(DThread* /*aThread*/, TRequestStatus* /*aStatus*/, TInt /*aReason*/)
	{
	// r0 -> DThread, r1 -> TRequestStatus in user space, r2 = aReason

	ASM_ASSERT_DATA_PAGING_SAFE;
	
#ifdef BTRACE_REQUESTS
	asm("stmdb sp!,{r0-r3,lr}");
	asm("mov r3,r2");											// arg3 = aReason
	asm("mov r2,r1");											// arg2 = aStatus
	asm("add r1,r0,#%a0" : : "i" _FOFF(DThread,iNThread));		// arg1 = &this->iNThread
	asm("ldr r0,_threadReqequestCompleteTraceHeader");			// arg0 = header
	asm("bl " CSM_ZN6BTrace4OutXEmmmm);
	asm("ldmia sp!,{r0-r3,lr}");
#endif

	ASM_DEBUG3(RequestComplete,r0,r1,r2);

	asm("ldrb r12, [r0, #%a0]" : : "i" _FOFF(DThread,iMState));
#ifdef __SMP__
	GET_RWNO_TID(,r3);		// NOTE: Can't migrate because we hold system lock
#else
	asm("ldr r3, __TheScheduler ");
#endif
	asm("stmfd sp!, {r4-r9} ");
	asm("add r6, r0, #%a0" : : "i" _FOFF(DThread,iNThread));				// r6->target NThread
#ifdef __SMP__
	asm("ldr r4, [r3, #%a0]" : : "i" _FOFF(TSubScheduler,iAddressSpace));	// r4->current process
#else
	asm("ldr r4, [r3, #%a0]" : : "i" _FOFF(TScheduler,iAddressSpace));		// r4->current process
#endif
	asm("ldr r0, [r0, #%a0]" : : "i" _FOFF(DThread,iOwningProcess));		// r0->target process
	asm("cmp r12, #%a0" : : "i" (DThread::EDead));	// test if iMState=EDead
	asm("beq req_complete_dead_thread ");	// if it is, finished
#ifdef __SMP__
	asm("ldr r5, [r3, #%a0]" : : "i" _FOFF(TSubScheduler,iCurrentThread));	// r5->current NThread
#else
	asm("ldr r5, [r3, #%a0]" : : "i" _FOFF(TScheduler,iCurrentThread));		// r5->current NThread
#endif

	asm("mrc p15, 0, r7, c2, c0, 0 ");		// save TTBR0
	asm("ldr r9, [r0, #%a0]" : : "i" _FOFF(DMemModelProcess,iPageDir));		// r9 -> target process page directory
	asm("and r12, r7, #%a0" : : "i" ((TInt)KTTBRExtraBitsMask));			// r12 = page table cache attributes
	// Get the os asid of the aThread's owning process, no need to open a reference 
	// as aThread is not dead and the system lock is held so it can't be made dead.
	asm("ldr r8, [r0, #%a0]" : : "i" _FOFF(DMemModelProcess,iOsAsid));		// r8 = target ASID
	asm("orr r9, r9, r12 ");				// r9 = new TTBR0 value

	__ASM_CLI(); // disable all interrupts
	__ASM_SET_ADDRESS_SPACE(r8,r9,r12);
#ifdef __SMP__
	asm("str r0, [r3, #%a0]" : : "i" _FOFF(TSubScheduler,iAddressSpace));
#else
	asm("str r0, [r3, #%a0]" : : "i" _FOFF(TScheduler,iAddressSpace));
#endif
	asm("str r0, [r5, #%a0]" : : "i" _FOFF(NThread,iAddressSpace));
	__ASM_STI(); // enable all interrupts

	USER_MEMORY_GUARD_OFF(,r12,r12);
	asm(".global __magic_address_reqc ");	// NOTE: Z flag always clear here
	asm("__magic_address_reqc: ");			// this instruction is magically immune from exceptions
	asm("strt r2, [r1] ");					// store completion code with user permissions
											// MAY MODIFY Z and R12
	USER_MEMORY_GUARD_ON(,r12,r12);

	asm("mrs r9, cpsr ");					// save CPSR and Z flag which indicates whether write succeeded
	// Read current process's os asid no reference required as it can't be freed as it is the current process. 
	asm("ldr r2, [r4, #%a0]" : : "i" _FOFF(DMemModelProcess,iOsAsid));		// r2 = current process ASID

	__ASM_CLI(); // disable all interrupts
	__ASM_SET_ADDRESS_SPACE(r2,r7,r12);
#ifdef __SMP__
	asm("str r4, [r3, #%a0]" : : "i" _FOFF(TSubScheduler,iAddressSpace));
#else
	asm("str r4, [r3, #%a0]" : : "i" _FOFF(TScheduler,iAddressSpace));
#endif
	asm("str r4, [r5, #%a0]" : : "i" _FOFF(NThread,iAddressSpace));

	asm("msr cpsr, r9 ");					// restore interrupts and Z flag

#ifdef __DEBUG_BAD_ADDR
	asm("moveq r12, #0xde000000 ");
	asm("streq r12, [r12, #0xaf] ");		//HACK-CRASH SYSTEM IF WRITE FAILED
#endif

	asm("movne r0, r6 ");					// if write OK, r0->iNThread
	asm("req_complete_dead_thread: ");		// NOTE: Z flag set if thread dead
	asm("ldmfd sp!, {r4-r9} ");				// restore registers whether OK or not
	asm("movne r1, #0 ");
	asm("bne " CSM_ZN5NKern19ThreadRequestSignalEP7NThreadP10NFastMutex );
	asm("b " CSM_ZN5NKern12UnlockSystemEv);	// if any error, unlock system and return

#ifdef BTRACE_REQUESTS
	asm("_threadReqequestCompleteTraceHeader:");
	asm(".word %a0" : : "i" (BTRACE_HEADER_C(16,BTrace::ERequests,BTrace::ERequestComplete)));
#endif
	}
#endif	//	__REQUEST_COMPLETE_MACHINE_CODED__


GLDEF_C __NAKED__ void DoProcessSwitch()
	{
	// Enter and return with kernel locked
	// UP: r0->scheduler, r3->current thread r2 = ContextID>>8
	// SMP: r11->subscheduler, r3->current thread r2 = ContextID>>8
	// r5->old process, r9->new process
	// UP: Must preserve r0,r3, can modify other registers
	// SMP: Must preserve r3,r10,r11, can modify other registers

	// Read the new process os asid, no need to open a reference as it is about 
	// to become the current thread.
	asm("ldr r4, [r9, #%a0]" : : "i" _FOFF(DMemModelProcess, iOsAsid));
	asm("ldr r6, [r3, #%a0]" : : "i" (_FOFF(DMemModelThread, iAliasLinAddr)-_FOFF(DThread, iNThread)) );
	asm("cmp r5, r9 ");					// check if current address space correct
	asm("orr r2, r4, r2, lsl #8 ");		// r2 = ContextID :  ASID
	asm("beq same_process");			// skip if address space change not required

	// switching to another process...
	asm("ldr r7, [r9, #%a0]" : : "i" _FOFF(DMemModelProcess, iPageDir));
	asm("mrc p15, 0, r8, c2, c0, 0 ");	// read current TTBR0
	asm("and r8, r8, #%a0" : : "i" ((TInt)KTTBRExtraBitsMask));
	asm("orr r7, r7, r8 ");
	// r7 now = new TTBR0

	__ASM_SET_ADDRESS_SPACE(r2,r7,r12);
#ifdef __SMP__
	asm("str r9, [r11, #%a0]" : : "i" _FOFF(TSubScheduler, iAddressSpace));
#else
	asm("str r9, [r0, #%a0]" : : "i" _FOFF(TScheduler, iAddressSpace));
#endif

	asm("cmp r6, #0");					// check if thread has an alias in place
	asm("bne got_alias");
	__JUMP(,lr);

	// 'switching' to same process, just update debug thread ID...
	asm("same_process:");
	__DATA_SYNC_BARRIER_Z__(r12);		// needed before change to ContextID
	asm("mcr p15, 0, r2, c13, c0, 1 ");	// set ASID + debugging thread ID
	__INST_SYNC_BARRIER__(r12);
	asm("cmp r6, #0");					// check if thread has an alias in place
	asm("bne got_alias");
	__JUMP(,lr);

	// restore alias...
	asm("got_alias:");
	asm("ldr r8, [r3, #%a0]" : : "i" (_FOFF(DMemModelThread, iAliasPdePtr)-_FOFF(DThread, iNThread)) );
	asm("ldr r7, [r3, #%a0]" : : "i" (_FOFF(DMemModelThread, iAliasPde)-_FOFF(DThread, iNThread)) );
	asm("orr r6, r6, r4");				// put ASID into address for TLB flush later...
	asm("str r7, [r8]");				// restore PDE for alias
	
	CACHE_MAINTENANCE_PDE_PTE_UPDATED(r8);

#if defined(__CPU_ARM11MP__) // why?...
	asm("mcr p15, 0, r6, c8, c7, 3 ");	// flush TLB for aliased page
#else
	asm("mcr p15, 0, r6, c8, c7, 1 ");	// flush TLB for aliased page
#endif
	asm("mov r8,#0");
	asm("mcr p15, 0, r8, c7, c5, 6 ");	// BPIALL (Branch predictor invalidate all)
	__DATA_SYNC_BARRIER__(r8);
	__INST_SYNC_BARRIER__(r8);
	__JUMP(,lr);

#ifndef __SMP__
	asm("__TheScheduler: ");
	asm(".word TheScheduler ");
#endif
	};

/**
Restore the address space of the current thread so it matches its owning process.
*/
__NAKED__ void DMemModelThread::RestoreAddressSpace()
	{
	asm("stmfd sp!, {lr} ");
#ifdef __SMP__
	GET_RWNO_TID(,r12);
	asm("ldr r3, [r12, #%a0]" : : "i" _FOFF(TSubScheduler,iCurrentThread));	// r3->current NThread
#else
	asm("ldr r12, __TheScheduler ");										// r12->TheScheduler
	asm("ldr r3, [r12, #%a0]" : : "i" _FOFF(TScheduler,iCurrentThread));	// r3->current NThread
#endif
	asm("ldr r0, [r3, #%a0]" : : "i" (-_FOFF(DThread,iNThread)+_FOFF(DThread,iOwningProcess)));		// r0->process

	// switch address space to process r0...
	asm("ldr r1, [r0, #%a0]" : : "i" _FOFF(DMemModelProcess,iPageDir));	// r1->process page directory
	asm("mrc p15, 0, r2, c2, c0, 0 ");
	asm("and r2, r2, #%a0" : : "i" ((TInt)KTTBRExtraBitsMask));
	asm("orr r1, r1, r2 ");
	// Get the os asid of the current process, no need to open a reference as it is the current process.
	asm("ldr r2, [r0, #%a0]" : : "i" _FOFF(DMemModelProcess,iOsAsid));		// r2 = ASID

	__ASM_CLI(); // disable all interrupts
	__ASM_SET_ADDRESS_SPACE(r2,r1,lr);
#ifdef __SMP__
	asm("str r0, [r12, #%a0]" : : "i" _FOFF(TSubScheduler,iAddressSpace));
#else
	asm("str r0, [r12, #%a0]" : : "i" _FOFF(TScheduler,iAddressSpace));
#endif
	asm("str r0, [r3, #%a0]" : : "i" _FOFF(NThread,iAddressSpace));
	__ASM_STI(); // enable all interrupts

	__POPRET("");
	}