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/*

 * Copyright (c) 2006 Martin Decky

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - 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.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * 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 THE AUTHOR 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.

 */

/** @addtogroup ppc32mm	

 * @{

 */

/** @file

 */

#include <mm/tlb.h>

#include <arch/mm/tlb.h>

#include <arch/interrupt.h>

#include <interrupt.h>

#include <mm/as.h>

#include <arch.h>

#include <print.h>

#include <symtab.h>

#include <macros.h>

static unsigned int seed = 10;

static unsigned int seed_real __attribute__ ((section("K_UNMAPPED_DATA_START"))) = 42;

/** Try to find PTE for faulting address

 *

 * Try to find PTE for faulting address.

 * The as->lock must be held on entry to this function

 * if lock is true.

 *

 * @param as		Address space.

 * @param lock		Lock/unlock the address space.

 * @param badvaddr	Faulting virtual address.

 * @param access	Access mode that caused the fault.

 * @param istate	Pointer to interrupted state.

 * @param pfrc		Pointer to variable where as_page_fault() return code

 * 			will be stored.

 * @return		PTE on success, NULL otherwise.

 *

 */

static pte_t *

find_mapping_and_check(as_t *as, bool lock, uintptr_t badvaddr, int access,

    istate_t *istate, int *pfrc)

{

	/*

	 * Check if the mapping exists in page tables.

	 */	

	pte_t *pte = page_mapping_find(as, badvaddr);

	if ((pte) && (pte->present)) {

		/*

		 * Mapping found in page tables.

		 * Immediately succeed.

		 */

		return pte;

	} else {

		int rc;

		/*

		 * Mapping not found in page tables.

		 * Resort to higher-level page fault handler.

		 */

		page_table_unlock(as, lock);

		switch (rc = as_page_fault(badvaddr, access, istate)) {

		case AS_PF_OK:

			/*

			 * The higher-level page fault handler succeeded,

			 * The mapping ought to be in place.

			 */

			page_table_lock(as, lock);

			pte = page_mapping_find(as, badvaddr);

			ASSERT((pte) && (pte->present));

			*pfrc = 0;

			return pte;

		case AS_PF_DEFER:

			page_table_lock(as, lock);

			*pfrc = rc;

			return NULL;

		case AS_PF_FAULT:

			page_table_lock(as, lock);

			*pfrc = rc;

			return NULL;

		default:

			panic("Unexpected rc (%d).", rc);

		}	

	}

}

static void pht_refill_fail(uintptr_t badvaddr, istate_t *istate)

{

	char *symbol = "";

	char *sym2 = "";

	char *str = get_symtab_entry(istate->pc);

	if (str)

		symbol = str;

	str = get_symtab_entry(istate->lr);

	if (str)

		sym2 = str;

	fault_if_from_uspace(istate,

	    "PHT Refill Exception on %p.", badvaddr);

	panic("%p: PHT Refill Exception at %p (%s<-%s).", badvaddr,

	    istate->pc, symbol, sym2);

}

static void pht_insert(const uintptr_t vaddr, const pte_t *pte)

{

	uint32_t page = (vaddr >> 12) & 0xffff;

	uint32_t api = (vaddr >> 22) & 0x3f;

	uint32_t vsid;

	asm volatile (

		"mfsrin %0, %1\n"

		: "=r" (vsid)

		: "r" (vaddr)

	);

	uint32_t sdr1;

	asm volatile (

		"mfsdr1 %0\n"

		: "=r" (sdr1)

	);

	phte_t *phte = (phte_t *) PA2KA(sdr1 & 0xffff0000);

	/* Primary hash (xor) */

	uint32_t h = 0;

	uint32_t hash = vsid ^ page;

	uint32_t base = (hash & 0x3ff) << 3;

	uint32_t i;

	bool found = false;

	/* Find colliding PTE in PTEG */

	for (i = 0; i < 8; i++) {

		if ((phte[base + i].v)

		    && (phte[base + i].vsid == vsid)

		    && (phte[base + i].api == api)

		    && (phte[base + i].h == 0)) {

			found = true;

			break;

		}

	}

	if (!found) {

		/* Find unused PTE in PTEG */

		for (i = 0; i < 8; i++) {

			if (!phte[base + i].v) {

				found = true;

				break;

			}

		}

	}

	if (!found) {

		/* Secondary hash (not) */

		uint32_t base2 = (~hash & 0x3ff) << 3;

		/* Find colliding PTE in PTEG */

		for (i = 0; i < 8; i++) {

			if ((phte[base2 + i].v)

			    && (phte[base2 + i].vsid == vsid)

			    && (phte[base2 + i].api == api)

			    && (phte[base2 + i].h == 1)) {

				found = true;

				base = base2;

				h = 1;

				break;

			}

		}

		if (!found) {

			/* Find unused PTE in PTEG */

			for (i = 0; i < 8; i++) {

				if (!phte[base2 + i].v) {

					found = true;

					base = base2;

					h = 1;

					break;

				}

			}

		}

		if (!found)

			i = RANDI(seed) % 8;

	}

	phte[base + i].v = 1;

	phte[base + i].vsid = vsid;

	phte[base + i].h = h;

	phte[base + i].api = api;

	phte[base + i].rpn = pte->pfn;

	phte[base + i].r = 0;

	phte[base + i].c = 0;

	phte[base + i].wimg = (pte->page_cache_disable ? WIMG_NO_CACHE : 0);

	phte[base + i].pp = 2; // FIXME

}

/** Process Instruction/Data Storage Interrupt

 *

 * @param n		Interrupt vector number.

 * @param istate	Interrupted register context.

 *

 */

void pht_refill(int n, istate_t *istate)

{

	uintptr_t badvaddr;

	pte_t *pte;

	int pfrc;

	as_t *as;

	bool lock;

	if (AS == NULL) {

		as = AS_KERNEL;

		lock = false;

	} else {

		as = AS;

		lock = true;

	}

	if (n == VECTOR_DATA_STORAGE)

		badvaddr = istate->dar;

	else

		badvaddr = istate->pc;

	page_table_lock(as, lock);

	pte = find_mapping_and_check(as, lock, badvaddr,

	    PF_ACCESS_READ /* FIXME */, istate, &pfrc);

	if (!pte) {

		switch (pfrc) {

		case AS_PF_FAULT:

			goto fail;

			break;

		case AS_PF_DEFER:

			/*

			 * The page fault came during copy_from_uspace()

			 * or copy_to_uspace().

			 */

			page_table_unlock(as, lock);

			return;

		default:

			panic("Unexpected pfrc (%d).", pfrc);

		}

	}

	pte->accessed = 1; /* Record access to PTE */

	pht_insert(badvaddr, pte);

	page_table_unlock(as, lock);

	return;

fail:

	page_table_unlock(as, lock);

	pht_refill_fail(badvaddr, istate);

}

/** Process Instruction/Data Storage Interrupt in Real Mode

 *

 * @param n		Interrupt vector number.

 * @param istate	Interrupted register context.

 *

 */

bool pht_refill_real(int n, istate_t *istate)

{

	uintptr_t badvaddr;

	if (n == VECTOR_DATA_STORAGE)

		badvaddr = istate->dar;

	else

		badvaddr = istate->pc;

	uint32_t physmem;

	asm volatile (

		"mfsprg3 %0\n"

		: "=r" (physmem)

	);

	if ((badvaddr < PA2KA(0)) || (badvaddr >= PA2KA(physmem)))

		return false;

	uint32_t page = (badvaddr >> 12) & 0xffff;

	uint32_t api = (badvaddr >> 22) & 0x3f;

	uint32_t vsid;

	asm volatile (

		"mfsrin %0, %1\n"

		: "=r" (vsid)

		: "r" (badvaddr)

	);

	uint32_t sdr1;

	asm volatile (

		"mfsdr1 %0\n"

		: "=r" (sdr1)

	);

	phte_t *phte_real = (phte_t *) (sdr1 & 0xffff0000);

	/* Primary hash (xor) */

	uint32_t h = 0;

	uint32_t hash = vsid ^ page;

	uint32_t base = (hash & 0x3ff) << 3;

	uint32_t i;

	bool found = false;

	/* Find colliding PTE in PTEG */

	for (i = 0; i < 8; i++) {

		if ((phte_real[base + i].v)

		    && (phte_real[base + i].vsid == vsid)

		    && (phte_real[base + i].api == api)

		    && (phte_real[base + i].h == 0)) {

			found = true;

			break;

		}

	}

	if (!found) {

		/* Find unused PTE in PTEG */

		for (i = 0; i < 8; i++) {

			if (!phte_real[base + i].v) {

				found = true;

				break;

			}

		}

	}

	if (!found) {

		/* Secondary hash (not) */

		uint32_t base2 = (~hash & 0x3ff) << 3;

		/* Find colliding PTE in PTEG */

		for (i = 0; i < 8; i++) {

			if ((phte_real[base2 + i].v)

			    && (phte_real[base2 + i].vsid == vsid)

			    && (phte_real[base2 + i].api == api)

			    && (phte_real[base2 + i].h == 1)) {

				found = true;

				base = base2;

				h = 1;

				break;

			}

		}

		if (!found) {

			/* Find unused PTE in PTEG */

			for (i = 0; i < 8; i++) {

				if (!phte_real[base2 + i].v) {

					found = true;

					base = base2;

					h = 1;

					break;

				}

			}

		}

		if (!found) {

			/* Use secondary hash to avoid collisions

			   with usual PHT refill handler. */

			i = RANDI(seed_real) % 8;

			base = base2;

			h = 1;

		}

	}

	phte_real[base + i].v = 1;

	phte_real[base + i].vsid = vsid;

	phte_real[base + i].h = h;

	phte_real[base + i].api = api;

	phte_real[base + i].rpn = KA2PA(badvaddr) >> 12;

	phte_real[base + i].r = 0;

	phte_real[base + i].c = 0;

	phte_real[base + i].wimg = 0;

	phte_real[base + i].pp = 2; // FIXME

	return true;

}

void tlb_arch_init(void)

{

	tlb_invalidate_all();

}

void tlb_invalidate_all(void)

{

	asm volatile (

		"tlbsync\n"

	);

}

void tlb_invalidate_asid(asid_t asid)

{

	uint32_t sdr1;

	asm volatile (

		"mfsdr1 %0\n"

		: "=r" (sdr1)

	);

	phte_t *phte = (phte_t *) PA2KA(sdr1 & 0xffff0000);

	uint32_t i;

	for (i = 0; i < 8192; i++) {

		if ((phte[i].v) && (phte[i].vsid >= (asid << 4)) &&

		    (phte[i].vsid < ((asid << 4) + 16)))

			phte[i].v = 0;

	}

	tlb_invalidate_all();

}

void tlb_invalidate_pages(asid_t asid, uintptr_t page, count_t cnt)

{

	// TODO

	tlb_invalidate_all();

}

#define PRINT_BAT(name, ureg, lreg) \

	asm volatile ( \

		"mfspr %0," #ureg "\n" \

		"mfspr %1," #lreg "\n" \

		: "=r" (upper), "=r" (lower) \

	); \

	mask = (upper & 0x1ffc) >> 2; \

	if (upper & 3) { \

		uint32_t tmp = mask; \

		length = 128; \

		while (tmp) { \

			if ((tmp & 1) == 0) { \

				printf("ibat[0]: error in mask\n"); \

				break; \

			} \

			length <<= 1; \

			tmp >>= 1; \

		} \

	} else \

		length = 0; \

	printf(name ": page=%.*p frame=%.*p length=%d KB (mask=%#x)%s%s\n", \

	    sizeof(upper) * 2, upper & 0xffff0000, sizeof(lower) * 2, \

	    lower & 0xffff0000, length, mask, \

	    ((upper >> 1) & 1) ? " supervisor" : "", \

	    (upper & 1) ? " user" : "");

void tlb_print(void)

{

	uint32_t sr;

	for (sr = 0; sr < 16; sr++) {

		uint32_t vsid;

		asm volatile (

			"mfsrin %0, %1\n"

			: "=r" (vsid)

			: "r" (sr << 28)

		);

		printf("sr[%02u]: vsid=%.*p (asid=%u)%s%s\n", sr,

		    sizeof(vsid) * 2, vsid & 0xffffff, (vsid & 0xffffff) >> 4,

		    ((vsid >> 30) & 1) ? " supervisor" : "",

		    ((vsid >> 29) & 1) ? " user" : "");

	}

	uint32_t upper;

	uint32_t lower;

	uint32_t mask;

	uint32_t length;

	PRINT_BAT("ibat[0]", 528, 529);

	PRINT_BAT("ibat[1]", 530, 531);

	PRINT_BAT("ibat[2]", 532, 533);

	PRINT_BAT("ibat[3]", 534, 535);

	PRINT_BAT("dbat[0]", 536, 537);

	PRINT_BAT("dbat[1]", 538, 539);

	PRINT_BAT("dbat[2]", 540, 541);

	PRINT_BAT("dbat[3]", 542, 543);

}

/** @}

 */