tlb.c

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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.
 */

#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>


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
}


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);
}


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);
}

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