/*
* Copyright (C) 2003-2004 Jakub Jermar
* 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 <arch/mm/tlb.h>
#include <arch/mm/asid.h>
#include <mm/tlb.h>
#include <mm/page.h>
#include <mm/vm.h>
#include <arch/cp0.h>
#include <panic.h>
#include <arch.h>
#include <symtab.h>
#include <synch/spinlock.h>
#include <print.h>
static void tlb_refill_fail(struct exception_regdump *pstate);
static void tlb_invalid_fail(struct exception_regdump *pstate);
static void tlb_modified_fail(struct exception_regdump *pstate);
static pte_t *find_mapping_and_check(__address badvaddr);
static void prepare_entry_lo(struct entry_lo *lo, bool g, bool v, bool d, bool c, __address pfn);
/** Initialize TLB
*
* Initialize TLB.
* Invalidate all entries and mark wired entries.
*/
void tlb_init_arch(void)
{
int i;
cp0_pagemask_write(TLB_PAGE_MASK_16K);
cp0_entry_hi_write(0);
cp0_entry_lo0_write(0);
cp0_entry_lo1_write(0);
/*
* Invalidate all entries.
*/
for (i = 0; i < TLB_SIZE; i++) {
cp0_index_write(i);
tlbwi();
}
/*
* The kernel is going to make use of some wired
* entries (e.g. mapping kernel stacks in kseg3).
*/
cp0_wired_write(TLB_WIRED);
}
/** Process TLB Refill Exception
*
* Process TLB Refill Exception.
*
* @param pstate Interrupted register context.
*/
void tlb_refill(struct exception_regdump *pstate)
{
struct entry_lo lo;
__address badvaddr;
pte_t *pte;
badvaddr = cp0_badvaddr_read();
spinlock_lock(&VM->lock);
pte = find_mapping_and_check(badvaddr);
if (!pte)
goto fail;
/*
* Record access to PTE.
*/
pte->a = 1;
prepare_entry_lo(&lo, pte->g, pte->v, pte->d, pte->c, pte->pfn);
/*
* New entry is to be inserted into TLB
*/
if ((badvaddr/PAGE_SIZE) % 2 == 0) {
cp0_entry_lo0_write(*((__u32 *) &lo));
cp0_entry_lo1_write(0);
}
else {
cp0_entry_lo0_write(0);
cp0_entry_lo1_write(*((__u32 *) &lo));
}
tlbwr();
spinlock_unlock(&VM->lock);
return;
fail:
spinlock_unlock(&VM->lock);
tlb_refill_fail(pstate);
}
/** Process TLB Invalid Exception
*
* Process TLB Invalid Exception.
*
* @param pstate Interrupted register context.
*/
void tlb_invalid(struct exception_regdump *pstate)
{
struct index index;
__address badvaddr;
struct entry_lo lo;
pte_t *pte;
badvaddr = cp0_badvaddr_read();
/*
* Locate the faulting entry in TLB.
*/
tlbp();
*((__u32 *) &index) = cp0_index_read();
spinlock_lock(&VM->lock);
/*
* Fail if the entry is not in TLB.
*/
if (index.p)
goto fail;
pte = find_mapping_and_check(badvaddr);
if (!pte)
goto fail;
/*
* Read the faulting TLB entry.
*/
tlbr();
/*
* Record access to PTE.
*/
pte->a = 1;
prepare_entry_lo(&lo, pte->g, pte->v, pte->d, pte->c, pte->pfn);
/*
* The entry is to be updated in TLB.
*/
if ((badvaddr/PAGE_SIZE) % 2 == 0)
cp0_entry_lo0_write(*((__u32 *) &lo));
else
cp0_entry_lo1_write(*((__u32 *) &lo));
tlbwi();
spinlock_unlock(&VM->lock);
return;
fail:
spinlock_unlock(&VM->lock);
tlb_invalid_fail(pstate);
}
/** Process TLB Modified Exception
*
* Process TLB Modified Exception.
*
* @param pstate Interrupted register context.
*/
void tlb_modified(struct exception_regdump *pstate)
{
struct index index;
__address badvaddr;
struct entry_lo lo;
pte_t *pte;
badvaddr = cp0_badvaddr_read();
/*
* Locate the faulting entry in TLB.
*/
tlbp();
*((__u32 *) &index) = cp0_index_read();
spinlock_lock(&VM->lock);
/*
* Fail if the entry is not in TLB.
*/
if (index.p)
goto fail;
pte = find_mapping_and_check(badvaddr);
if (!pte)
goto fail;
/*
* Fail if the page is not writable.
*/
if (!pte->w)
goto fail;
/*
* Read the faulting TLB entry.
*/
tlbr();
/*
* Record access and write to PTE.
*/
pte->a = 1;
pte->d = 1;
prepare_entry_lo(&lo, pte->g, pte->v, pte->w, pte->c, pte->pfn);
/*
* The entry is to be updated in TLB.
*/
if ((badvaddr/PAGE_SIZE) % 2 == 0)
cp0_entry_lo0_write(*((__u32 *) &lo));
else
cp0_entry_lo1_write(*((__u32 *) &lo));
tlbwi();
spinlock_unlock(&VM->lock);
return;
fail:
spinlock_unlock(&VM->lock);
tlb_modified_fail(pstate);
}
void tlb_refill_fail(struct exception_regdump *pstate)
{
char *symbol = "";
char *sym2 = "";
char *s = get_symtab_entry(pstate->epc);
if (s)
symbol = s;
s = get_symtab_entry(pstate->ra);
if (s)
sym2 = s;
panic("%X: TLB Refill Exception at %X(%s<-%s)\n", cp0_badvaddr_read(), pstate->epc, symbol, sym2);
}
void tlb_invalid_fail(struct exception_regdump *pstate)
{
char *symbol = "";
char *s = get_symtab_entry(pstate->epc);
if (s)
symbol = s;
panic("%X: TLB Invalid Exception at %X(%s)\n", cp0_badvaddr_read(), pstate->epc, symbol);
}
void tlb_modified_fail(struct exception_regdump *pstate)
{
char *symbol = "";
char *s = get_symtab_entry(pstate->epc);
if (s)
symbol = s;
panic("%X: TLB Modified Exception at %X(%s)\n", cp0_badvaddr_read(), pstate->epc, symbol);
}
void tlb_invalidate(int asid)
{
pri_t pri;
pri = cpu_priority_high();
// TODO
cpu_priority_restore(pri);
}
/** Try to find PTE for faulting address
*
* Try to find PTE for faulting address.
* The VM->lock must be held on entry to this function.
*
* @param badvaddr Faulting virtual address.
*
* @return PTE on success, NULL otherwise.
*/
pte_t *find_mapping_and_check(__address badvaddr)
{
struct entry_hi hi;
pte_t *pte;
*((__u32 *) &hi) = cp0_entry_hi_read();
/*
* Handler cannot succeed if the ASIDs don't match.
*/
if (hi.asid != VM->asid)
return NULL;
/*
* Handler cannot succeed if badvaddr has no mapping.
*/
pte = find_mapping(badvaddr, 0);
if (!pte)
return NULL;
/*
* Handler cannot succeed if the mapping is marked as invalid.
*/
if (!pte->v)
return NULL;
return pte;
}
void prepare_entry_lo(struct entry_lo *lo, bool g, bool v, bool d, bool c, __address pfn)
{
lo->g = g;
lo->v = v;
lo->d = d;
lo->c = c;
lo->pfn = pfn;
lo->zero = 0;
}