On 12/01/2016 05:51 AM, Jin Guojie wrote:
> Changes in v5:
> * Update against master(v2.8.0-rc2)
> * Fix a bug: 64-bit big-endian guests hang on mips64 little-endian
> hosts, and vice versa. This bug was first introduced in v2 patch,
> due to obvious misuse of ret/arg registers in tcg_out_bswap64().
>
> tcg_out_opc_reg(s, OPC_DSBH, ret, 0, arg);
> - tcg_out_opc_reg(s, OPC_DSHD, ret, 0, arg);
> + tcg_out_opc_reg(s, OPC_DSHD, ret, 0, ret);
Oops. Thanks.
> * Fix a style problem: checkpatch.pl forbids 'extern' to be used in .c.
>
> ERROR: externs should be avoided in .c files
> #28: FILE: tcg/mips/tcg-target.inc.c:39:
> +extern int link_error(void);
Hmph. This is checkpatch not being helpful, but your change is fine.
I've looked at a diff between your current patch and the last update I had to
my branch. This probably includes code that post-dates the v2 that you started
with. There are two things I'd like to point out:
@@ -1233,7 +1235,8 @@ static void tcg_out_tlb_load(TCGContext *s, TCGReg base,
TCGReg addrl,
if (a_bits < s_bits) {
a_bits = s_bits;
}
- mask = (target_ulong)TARGET_PAGE_MASK | ((1 << a_bits) - 1);
+
+ mask = TARGET_PAGE_MASK | ((1 << a_bits) - 1);
You need the target_ulong cast here for mips64.
See patch ebb90a005da67147245cd38fb04a965a87a961b7.
if (TCG_TARGET_REG_BITS > TARGET_LONG_BITS) {
- tcg_out_ext32u(s, base, addrl);
- addrl = base;
+ tcg_out_ext32u(s, TCG_TMP0, TCG_TMP0);
}
Why did you make this change? It is definitely wrong.
We should be zero-extending the guest address, not the address that we just
loaded from CMP_OFF. This is because we need to add an unsigned 32-bit
quantity to the full 64-bit host pointer that we load from ADD_OFF.
Did you notice a compare problem between TMP1 and TMP0 below? If so, I believe
that a partial solution is the TARGET_PAGE_MASK change above. I guess we also
need to do
tcg_out_ldst(s, (TARGET_LONG_BITS == 64 ? OPC_LD
TCG_TARGET_REG_BITS == 64 : OPC_LWU : OPC_LW),
TCG_TMP0, TCG_REG_A0, cmp_off);
in the else section of the tlb comparator load above, since mask will be 32-bit
unsigned for TARGET_LONG_BITS == 32, and we need an unsigned quantity to
compare that against.
r~
PS: Ignoring N32 for now. But as a note to ourselves for future: What is the
proper combination of zero/sign-extend vs ADDU/DADDU for 32/64-bit guests and
an N32 host? What we have now is technically illegal, with zero-extend + ADDU.
But I can imagine several valid scenarios.
