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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 <mm/as.h>
#include <arch.h>
#include <print.h>
#include <symtab.h>


/** 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, __address 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->p)) {
        /*
         * 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->p));
                return pte;
            case AS_PF_DEFER:
                page_table_lock(as, lock);
                *pfrc = rc;
                return NULL;
            case AS_PF_FAULT:
                page_table_lock(as, lock);
                printf("Page fault.\n");
                *pfrc = rc;
                return NULL;
            default:
                panic("unexpected rc (%d)\n", rc);
        }  
    }
}


static void pht_refill_fail(__address badvaddr, istate_t *istate)
{
    char *symbol = "";
    char *sym2 = "";

    char *s = get_symtab_entry(istate->pc);
    if (s)
        symbol = s;
    s = get_symtab_entry(istate->lr);
    if (s)
        sym2 = s;
    panic("%p: PHT Refill Exception at %p (%s<-%s)\n", badvaddr, istate->pc, symbol, sym2);
}


static void pht_insert(const __address vaddr, const pfn_t pfn)
{
    __u32 page = (vaddr >> 12) & 0xffff;
    __u32 api = (vaddr >> 22) & 0x3f;
   
    __u32 vsid;
    asm volatile (
        "mfsrin %0, %1\n"
        : "=r" (vsid)
        : "r" (vaddr)
    );
   
    __u32 sdr1;
    asm volatile (
        "mfsdr1 %0\n"
        : "=r" (sdr1)
    );
    phte_t *phte = (phte_t *) PA2KA(sdr1 & 0xffff0000);
   
    /* Primary hash (xor) */
    __u32 h = 0;
    __u32 hash = vsid ^ page;
    __u32 base = (hash & 0x3ff) << 3;
    __u32 i;
    bool found = false;
   
    /* Find unused or 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))) {
            found = true;
            break;
        }
    }
   
    if (!found) {
        /* Secondary hash (not) */
        __u32 base2 = (~hash & 0x3ff) << 3;
       
        /* Find unused or 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))) {
                found = true;
                base = base2;
                h = 1;
                break;
            }
        }
       
        if (!found) {
            // TODO: A/C precedence groups
            i = page % 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 = pfn;
    phte[base + i].r = 0;
    phte[base + i].c = 0;
    phte[base + i].pp = 2; // FIXME
}


static void pht_real_insert(const __address vaddr, const pfn_t pfn)
{
    __u32 page = (vaddr >> 12) & 0xffff;
    __u32 api = (vaddr >> 22) & 0x3f;
   
    __u32 vsid;
    asm volatile (
        "mfsrin %0, %1\n"
        : "=r" (vsid)
        : "r" (vaddr)
    );
   
    __u32 sdr1;
    asm volatile (
        "mfsdr1 %0\n"
        : "=r" (sdr1)
    );
    phte_t *phte_physical = (phte_t *) (sdr1 & 0xffff0000);
   
    /* Primary hash (xor) */
    __u32 h = 0;
    __u32 hash = vsid ^ page;
    __u32 base = (hash & 0x3ff) << 3;
    __u32 i;
    bool found = false;
   
    /* Find unused or colliding
       PTE in PTEG */

    for (i = 0; i < 8; i++) {
        if ((!phte_physical[base + i].v) || ((phte_physical[base + i].vsid == vsid) && (phte_physical[base + i].api == api))) {
            found = true;
            break;
        }
    }
   
    if (!found) {
        /* Secondary hash (not) */
        __u32 base2 = (~hash & 0x3ff) << 3;
       
        /* Find unused or colliding
           PTE in PTEG */

        for (i = 0; i < 8; i++) {
            if ((!phte_physical[base2 + i].v) || ((phte_physical[base2 + i].vsid == vsid) && (phte_physical[base2 + i].api == api))) {
                found = true;
                base = base2;
                h = 1;
                break;
            }
        }
       
        if (!found) {
            // TODO: A/C precedence groups
            i = page % 8;
        }
    }
   
    phte_physical[base + i].v = 1;
    phte_physical[base + i].vsid = vsid;
    phte_physical[base + i].h = h;
    phte_physical[base + i].api = api;
    phte_physical[base + i].rpn = pfn;
    phte_physical[base + i].r = 0;
    phte_physical[base + i].c = 0;
    phte_physical[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)
{
    __address 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) {
        asm volatile (
            "mfdar %0\n"
            : "=r" (badvaddr)
        );
    } 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)\n", pfrc);
        }
    }
   
    pte->a = 1; /* Record access to PTE */
    pht_insert(badvaddr, pte->pfn);
   
    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_real_refill(int n, istate_t *istate)
{
    __address badvaddr;
   
    if (n == VECTOR_DATA_STORAGE) {
        asm volatile (
            "mfdar %0\n"
            : "=r" (badvaddr)
        );
    } else
        badvaddr = istate->pc;
   
    __u32 physmem;
    asm volatile (
        "mfsprg3 %0\n"
        : "=r" (physmem)
    );
   
    if ((badvaddr >= PA2KA(0)) && (badvaddr < PA2KA(physmem))) {
        pht_real_insert(badvaddr, KA2PA(badvaddr) >> 12);
        return true;
    }
   
    return false;
}


void tlb_arch_init(void)
{
    tlb_invalidate_all();
}


void tlb_invalidate_all(void)
{
    asm volatile (
        "tlbia\n"
        "tlbsync\n"
    );
}


void tlb_invalidate_asid(asid_t asid)
{
    // TODO
    tlb_invalidate_all();
}


void tlb_invalidate_pages(asid_t asid, __address 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) { \
        __u32 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)
{
    __u32 sr;
   
    for (sr = 0; sr < 16; sr++) {
        __u32 vsid;
        asm volatile (
            "mfsrin %0, %1\n"
            : "=r" (vsid)
            : "r" (sr << 28)
        );
        printf("vsid[%d]: VSID=%.*p (ASID=%d)%s%s\n", sr, sizeof(vsid) * 2, vsid & 0xffffff, (vsid & 0xffffff) >> 4, ((vsid >> 30) & 1) ? " supervisor" : "", ((vsid >> 29) & 1) ? " user" : "");
    }
   
    __u32 upper;
    __u32 lower;
    __u32 mask;
    __u32 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);
}

/** @}
 */