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xtensa: fix OOB TLB entry access #42

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xtensa: fix OOB TLB entry access #42

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45 changes: 34 additions & 11 deletions arch/xtensa/mmu_helper.c
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Original file line number Diff line number Diff line change
Expand Up @@ -201,20 +201,29 @@ static void split_tlb_entry_spec_way(const CPUState *env, uint32_t v, bool dtlb,
* Split TLB address into TLB way, entry index and VPN (with index).
* See ISA, 4.6.5.5 - 4.6.5.8 for the TLB addressing format
*/
static void split_tlb_entry_spec(CPUState *env, uint32_t v, bool dtlb, uint32_t *vpn, uint32_t *wi, uint32_t *ei)
static bool split_tlb_entry_spec(CPUState *env, uint32_t v, bool dtlb, uint32_t *vpn, uint32_t *wi, uint32_t *ei)
{
if(xtensa_option_enabled(env->config, XTENSA_OPTION_MMU)) {
*wi = v & (dtlb ? 0xf : 0x7);
split_tlb_entry_spec_way(env, v, dtlb, vpn, *wi, ei);
if(*wi < (dtlb ? env->config->dtlb.nways : env->config->itlb.nways)) {
split_tlb_entry_spec_way(env, v, dtlb, vpn, *wi, ei);
return true;
} else {
return false;
}
} else {
*vpn = v & REGION_PAGE_MASK;
*wi = 0;
*ei = (v >> 29) & 0x7;
return true;
}
}

static xtensa_tlb_entry *xtensa_tlb_get_entry(CPUState *env, bool dtlb, unsigned wi, unsigned ei)
{
const xtensa_tlb *tlb = dtlb ? &env->config->dtlb : &env->config->itlb;

tlib_assert(wi < tlb->nways && ei < tlb->way_size[wi]);
return dtlb ? env->dtlb[wi] + ei : env->itlb[wi] + ei;
}

Expand All @@ -224,11 +233,14 @@ static xtensa_tlb_entry *get_tlb_entry(CPUState *env, uint32_t v, bool dtlb, uin
uint32_t wi;
uint32_t ei;

split_tlb_entry_spec(env, v, dtlb, &vpn, &wi, &ei);
if(pwi) {
*pwi = wi;
if(split_tlb_entry_spec(env, v, dtlb, &vpn, &wi, &ei)) {
if(pwi) {
*pwi = wi;
}
return xtensa_tlb_get_entry(env, dtlb, wi, ei);
} else {
return NULL;
}
return xtensa_tlb_get_entry(env, dtlb, wi, ei);
}

static void xtensa_tlb_set_entry_mmu(const CPUState *env, xtensa_tlb_entry *entry, bool dtlb, unsigned wi, unsigned ei,
Expand Down Expand Up @@ -416,7 +428,12 @@ uint32_t HELPER(rtlb0)(CPUState *env, uint32_t v, uint32_t dtlb)
if(xtensa_option_enabled(env->config, XTENSA_OPTION_MMU)) {
uint32_t wi;
const xtensa_tlb_entry *entry = get_tlb_entry(env, v, dtlb, &wi);
return (entry->vaddr & get_vpn_mask(env, dtlb, wi)) | entry->asid;

if(entry) {
return (entry->vaddr & get_vpn_mask(env, dtlb, wi)) | entry->asid;
} else {
return 0;
}
} else {
return v & REGION_PAGE_MASK;
}
Expand All @@ -425,15 +442,20 @@ uint32_t HELPER(rtlb0)(CPUState *env, uint32_t v, uint32_t dtlb)
uint32_t HELPER(rtlb1)(CPUState *env, uint32_t v, uint32_t dtlb)
{
const xtensa_tlb_entry *entry = get_tlb_entry(env, v, dtlb, NULL);
return entry->paddr | entry->attr;

if(entry) {
return entry->paddr | entry->attr;
} else {
return 0;
}
}

void HELPER(itlb)(CPUState *env, uint32_t v, uint32_t dtlb)
{
if(xtensa_option_enabled(env->config, XTENSA_OPTION_MMU)) {
uint32_t wi;
xtensa_tlb_entry *entry = get_tlb_entry(env, v, dtlb, &wi);
if(entry->variable && entry->asid) {
if(entry && entry->variable && entry->asid) {
tlb_flush_page(env, entry->vaddr, true);
entry->asid = 0;
}
Expand Down Expand Up @@ -471,8 +493,9 @@ void HELPER(wtlb)(CPUState *env, uint32_t p, uint32_t v, uint32_t dtlb)
uint32_t vpn;
uint32_t wi;
uint32_t ei;
split_tlb_entry_spec(env, v, dtlb, &vpn, &wi, &ei);
xtensa_tlb_set_entry(env, dtlb, wi, ei, vpn, p);
if(split_tlb_entry_spec(env, v, dtlb, &vpn, &wi, &ei)) {
xtensa_tlb_set_entry(env, dtlb, wi, ei, vpn, p);
}
}

/*!
Expand Down