/*
* 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 kernel_ppc32_mm
* @{
*/
/** @file
*/
#include <arch/mm/pht.h>
#include <arch/mm/tlb.h>
#include <assert.h>
#include <interrupt.h>
#include <mm/as.h>
#include <mm/page.h>
#include <macros.h>
#include <typedefs.h>
static unsigned int seed = 42;
/** Try to find PTE for faulting address
*
* @param as Address space.
* @param badvaddr Faulting virtual address.
* @param access Access mode that caused the fault.
* @param istate Pointer to interrupted state.
* @param[out] pte Structure that will receive a copy of the found PTE.
*
* @return True if the mapping was found, false otherwise.
*
*/
static bool find_mapping_and_check(as_t *as, uintptr_t badvaddr, int access,
istate_t *istate, pte_t *pte)
{
/*
* Check if the mapping exists in page tables.
*/
bool found = page_mapping_find(as, badvaddr, true, pte);
if (found && pte->present) {
/*
* Mapping found in page tables.
* Immediately succeed.
*/
return true;
}
/*
* Mapping not found in page tables.
* Resort to higher-level page fault handler.
*/
if (as_page_fault(badvaddr, access, istate) == AS_PF_OK) {
/*
* The higher-level page fault handler succeeded,
* The mapping ought to be in place.
*/
found = page_mapping_find(as, badvaddr, true, pte);
assert(found);
assert(pte->present);
return found;
}
return false;
}
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 = sr_get(vaddr);
uint32_t sdr1 = sdr1_get();
// FIXME: compute size of PHT exactly
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 Exception
*
* @param n Exception vector number.
* @param istate Interrupted register context.
*
*/
void pht_refill(unsigned int n, istate_t *istate)
{
uintptr_t badvaddr;
if (n == VECTOR_DATA_STORAGE)
badvaddr = istate->dar;
else
badvaddr = istate->pc;
pte_t pte;
bool found = find_mapping_and_check(AS, badvaddr,
PF_ACCESS_READ /* FIXME */, istate, &pte);
if (found) {
/* Record access to PTE */
pte.accessed = 1;
pht_insert(badvaddr, &pte);
}
}
void pht_invalidate(as_t *as, uintptr_t page, size_t pages)
{
uint32_t sdr1 = sdr1_get();
// FIXME: compute size of PHT exactly
phte_t *phte = (phte_t *) PA2KA(sdr1 & 0xffff0000);
// FIXME: this invalidates all PHT entries,
// which is an overkill, invalidate only
// selectively
for (size_t i = 0; i < 8192; i++) {
phte[i].v = 0;
}
}
/** @}
*/