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 <da...@gibson.dropbear.id.au>
Reviewed-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
---
target-ppc/mmu-hash64.c | 99 ++++++++++++++++++++-----------------------------
1 file changed, 41 insertions(+), 58 deletions(-)
diff --git a/target-ppc/mmu-hash64.c b/target-ppc/mmu-hash64.c
index a15ef83..6d3428e 100644
--- a/target-ppc/mmu-hash64.c
+++ b/target-ppc/mmu-hash64.c
@@ -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;
+ }
+
+ 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;
}
- return 0;
- case 24:
- if ((pte1 & 0xff000) == 0) {
- return 24;
+
+ 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;
}
- return 0;
+
+ 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)
{
--
2.7.4
