cpu: Move the softmmu tlb to CPUNegativeOffsetState

We have for some time had code within the tcg backends to
handle large positive offsets from env.  This move makes
sure that need not happen.  Indeed, we are able to assert
at build time that simple offsets suffice for all hosts.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 8 insertions, 32 deletions

diff --git a/tcg/arm/tcg-target.inc.c b/tcg/arm/tcg-target.inc.c
index 38de6d59c7..b066e30f0e 100644
--- a/tcg/arm/tcg-target.inc.c
+++ b/tcg/arm/tcg-target.inc.c
@@ -1220,9 +1220,9 @@ static TCGReg tcg_out_arg_reg64(TCGContext *s, TCGReg argreg,
 
 #define TLB_SHIFT	(CPU_TLB_ENTRY_BITS + CPU_TLB_BITS)
 
-/* We expect to use a 20-bit unsigned offset from ENV.  */
-QEMU_BUILD_BUG_ON(offsetof(CPUArchState, tlb_.f[NB_MMU_MODES - 1].table)
-                  > 0xfffff);
+/* We expect to use an 9-bit sign-magnitude negative offset from ENV.  */
+QEMU_BUILD_BUG_ON(TLB_MASK_TABLE_OFS(0) > 0);
+QEMU_BUILD_BUG_ON(TLB_MASK_TABLE_OFS(0) < -256);
 
 /* Load and compare a TLB entry, leaving the flags set.  Returns the register
    containing the addend of the tlb entry.  Clobbers R0, R1, R2, TMP.  */
@@ -1232,39 +1232,15 @@ static TCGReg tcg_out_tlb_read(TCGContext *s, TCGReg addrlo, TCGReg addrhi,
 {
     int cmp_off = (is_load ? offsetof(CPUTLBEntry, addr_read)
                    : offsetof(CPUTLBEntry, addr_write));
-    int mask_off = offsetof(CPUArchState, tlb_.f[mem_index].mask);
-    int table_off = offsetof(CPUArchState, tlb_.f[mem_index].table);
-    TCGReg mask_base = TCG_AREG0, table_base = TCG_AREG0;
+    int fast_off = TLB_MASK_TABLE_OFS(mem_index);
+    int mask_off = fast_off + offsetof(CPUTLBDescFast, mask);
+    int table_off = fast_off + offsetof(CPUTLBDescFast, table);
     unsigned s_bits = opc & MO_SIZE;
     unsigned a_bits = get_alignment_bits(opc);
 
-    if (table_off > 0xfff) {
-        int mask_hi = mask_off & ~0xfff;
-        int table_hi = table_off & ~0xfff;
-        int rot;
-
-        table_base = TCG_REG_R2;
-        if (mask_hi == table_hi) {
-            mask_base = table_base;
-        } else if (mask_hi) {
-            mask_base = TCG_REG_TMP;
-            rot = encode_imm(mask_hi);
-            assert(rot >= 0);
-            tcg_out_dat_imm(s, COND_AL, ARITH_ADD, mask_base, TCG_AREG0,
-                            rotl(mask_hi, rot) | (rot << 7));
-        }
-        rot = encode_imm(table_hi);
-        assert(rot >= 0);
-        tcg_out_dat_imm(s, COND_AL, ARITH_ADD, table_base, TCG_AREG0,
-                        rotl(table_hi, rot) | (rot << 7));
-
-        mask_off -= mask_hi;
-        table_off -= table_hi;
-    }
-
     /* Load tlb_mask[mmu_idx] and tlb_table[mmu_idx].  */
-    tcg_out_ld(s, TCG_TYPE_I32, TCG_REG_TMP, mask_base, mask_off);
-    tcg_out_ld(s, TCG_TYPE_I32, TCG_REG_R2, table_base, table_off);
+    tcg_out_ld(s, TCG_TYPE_I32, TCG_REG_TMP, TCG_AREG0, mask_off);
+    tcg_out_ld(s, TCG_TYPE_I32, TCG_REG_R2, TCG_AREG0, table_off);
 
     /* Extract the tlb index from the address into TMP.  */
     tcg_out_dat_reg(s, COND_AL, ARITH_AND, TCG_REG_TMP, TCG_REG_TMP, addrlo,