target/mips: Fix TLBWI shadow flush for EHINV,XI,RI

Writing specific TLB entries with TLBWI flushes shadow TLB entries
unless an existing entry is having its access permissions upgraded. This
is necessary as software would from then on expect the previous mapping
in that entry to no longer be in effect (even if QEMU has quietly
evicted it to the shadow TLB on a TLBWR).

However it won't do this if only EHINV, XI, or RI bits have been set,
even if that results in a reduction of permissions, so add the necessary
checks to invoke the flush when these bits are set.

Backports commit eff6ff9431aa9776062a5f4a08d1f6503ca9995a from qemu
This commit is contained in:
James Hogan 2018-03-03 23:39:16 -05:00 committed by Lioncash
parent fe0de45a26
commit 310e3f0a1d
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GPG key ID: 4E3C3CC1031BA9C7

View file

@ -2007,7 +2007,7 @@ void r4k_helper_tlbwi(CPUMIPSState *env)
int idx;
target_ulong VPN;
uint16_t ASID;
bool G, V0, D0, V1, D1;
bool EHINV, G, V0, D0, V1, D1, XI0, XI1, RI0, RI1;
idx = (env->CP0_Index & ~0x80000000) % env->tlb->nb_tlb;
tlb = &env->tlb->mmu.r4k.tlb[idx];
@ -2016,17 +2016,25 @@ void r4k_helper_tlbwi(CPUMIPSState *env)
VPN &= env->SEGMask;
#endif
ASID = env->CP0_EntryHi & env->CP0_EntryHi_ASID_mask;
EHINV = (env->CP0_EntryHi & (1 << CP0EnHi_EHINV)) != 0;
G = env->CP0_EntryLo0 & env->CP0_EntryLo1 & 1;
V0 = (env->CP0_EntryLo0 & 2) != 0;
D0 = (env->CP0_EntryLo0 & 4) != 0;
XI0 = (env->CP0_EntryLo0 >> CP0EnLo_XI) &1;
RI0 = (env->CP0_EntryLo0 >> CP0EnLo_RI) &1;
V1 = (env->CP0_EntryLo1 & 2) != 0;
D1 = (env->CP0_EntryLo1 & 4) != 0;
XI1 = (env->CP0_EntryLo1 >> CP0EnLo_XI) &1;
RI1 = (env->CP0_EntryLo1 >> CP0EnLo_RI) &1;
/* Discard cached TLB entries, unless tlbwi is just upgrading access
permissions on the current entry. */
if (tlb->VPN != VPN || tlb->ASID != ASID || tlb->G != G ||
(!tlb->EHINV && EHINV) ||
(tlb->V0 && !V0) || (tlb->D0 && !D0) ||
(tlb->V1 && !V1) || (tlb->D1 && !D1)) {
(!tlb->XI0 && XI0) || (!tlb->RI0 && RI0) ||
(tlb->V1 && !V1) || (tlb->D1 && !D1) ||
(!tlb->XI1 && XI1) || (!tlb->RI1 && RI1)) {
r4k_mips_tlb_flush_extra(env, env->tlb->nb_tlb);
}