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target-ppc: Correct page size decoding in ppc_hash64_pteg_search() 

The architecture specifies that when searching a PTEG for PTEs, entries
with a page size encoding that's not valid for the current segment should
be ignored, continuing the search.

The current implementation does this with ppc_hash64_pte_size_decode()
which is a very incomplete implementation of this check.  We already have
code to do a full and correct page size decode in hpte_page_shift().

This patch moves hpte_page_shift() so it can be used in
ppc_hash64_pteg_search() and adjusts the latter's parameters to include
a full SLBE instead of just a segment page shift.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
David Gibson 2016-07-05 12:17:56 +10:00
parent 1f0252e66e
commit 651060aba7
1 changed files with 43 additions and 60 deletions
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103
target-ppc/mmu-hash64.c
View File

@ -450,30 +450,45 @@ void ppc_hash64_stop_access(PowerPCCPU *cpu, uint64_t token)
}
}
/* Returns the effective page shift or 0. MPSS isn't supported yet so
* this will always be the slb_pshift or 0
*/
static uint32_t ppc_hash64_pte_size_decode(uint64_t pte1, uint32_t slb_pshift)
static unsigned hpte_page_shift(const struct ppc_one_seg_page_size *sps,
uint64_t pte0, uint64_t pte1)
{
switch (slb_pshift) {
case 12:
int i;
if (!(pte0 & HPTE64_V_LARGE)) {
if (sps->page_shift != 12) {
/* 4kiB page in a non 4kiB segment */
return 0;
}
/* Normal 4kiB page */
return 12;
case 16:
if ((pte1 & 0xf000) == 0x1000) {
return 16;
}
return 0;
case 24:
if ((pte1 & 0xff000) == 0) {
return 24;
}
return 0;
}
return 0;
for (i = 0; i < PPC_PAGE_SIZES_MAX_SZ; i++) {
const struct ppc_one_page_size *ps = &sps->enc[i];
uint64_t mask;
if (!ps->page_shift) {
break;
}
if (ps->page_shift == 12) {
/* L bit is set so this can't be a 4kiB page */
continue;
}
mask = ((1ULL << ps->page_shift) - 1) & HPTE64_R_RPN;
if ((pte1 & mask) == (ps->pte_enc << HPTE64_R_RPN_SHIFT)) {
return ps->page_shift;
}
}
return 0; /* Bad page size encoding */
}
static hwaddr ppc_hash64_pteg_search(PowerPCCPU *cpu, hwaddr hash,
uint32_t slb_pshift, bool secondary,
ppc_slb_t *slb, bool secondary,
target_ulong ptem, ppc_hash_pte64_t *pte)
{
CPUPPCState *env = &cpu->env;
@ -494,7 +509,14 @@ static hwaddr ppc_hash64_pteg_search(PowerPCCPU *cpu, hwaddr hash,
if ((pte0 & HPTE64_V_VALID)
&& (secondary == !!(pte0 & HPTE64_V_SECONDARY))
&& HPTE64_V_COMPARE(pte0, ptem)) {
uint32_t pshift = ppc_hash64_pte_size_decode(pte1, slb_pshift);
unsigned pshift = hpte_page_shift(slb->sps, pte0, pte1);
/*
* If there is no match, ignore the PTE, it could simply
* be for a different segment size encoding and the
* architecture specifies we should not match. Linux will
* potentially leave behind PTEs for the wrong base page
* size when demoting segments.
*/
if (pshift == 0) {
continue;
}
@ -554,8 +576,7 @@ static hwaddr ppc_hash64_htab_lookup(PowerPCCPU *cpu,
" vsid=" TARGET_FMT_lx " ptem=" TARGET_FMT_lx
" hash=" TARGET_FMT_plx "\n",
env->htab_base, env->htab_mask, vsid, ptem, hash);
pte_offset = ppc_hash64_pteg_search(cpu, hash, slb->sps->page_shift,
0, ptem, pte);
pte_offset = ppc_hash64_pteg_search(cpu, hash, slb, 0, ptem, pte);
if (pte_offset == -1) {
/* Secondary PTEG lookup */
@ -565,50 +586,12 @@ static hwaddr ppc_hash64_htab_lookup(PowerPCCPU *cpu,
" hash=" TARGET_FMT_plx "\n", env->htab_base,
env->htab_mask, vsid, ptem, ~hash);
pte_offset = ppc_hash64_pteg_search(cpu, ~hash, slb->sps->page_shift, 1,
ptem, pte);
pte_offset = ppc_hash64_pteg_search(cpu, ~hash, slb, 1, ptem, pte);
}
return pte_offset;
}
static unsigned hpte_page_shift(const struct ppc_one_seg_page_size *sps,
uint64_t pte0, uint64_t pte1)
{
int i;
if (!(pte0 & HPTE64_V_LARGE)) {
if (sps->page_shift != 12) {
/* 4kiB page in a non 4kiB segment */
return 0;
}
/* Normal 4kiB page */
return 12;
}
for (i = 0; i < PPC_PAGE_SIZES_MAX_SZ; i++) {
const struct ppc_one_page_size *ps = &sps->enc[i];
uint64_t mask;
if (!ps->page_shift) {
break;
}
if (ps->page_shift == 12) {
/* L bit is set so this can't be a 4kiB page */
continue;
}
mask = ((1ULL << ps->page_shift) - 1) & HPTE64_R_RPN;
if ((pte1 & mask) == (ps->pte_enc << HPTE64_R_RPN_SHIFT)) {
return ps->page_shift;
}
}
return 0; /* Bad page size encoding */
}
unsigned ppc_hash64_hpte_page_shift_noslb(PowerPCCPU *cpu,
uint64_t pte0, uint64_t pte1)
{