[PATCH] target/riscv: rvzicbo: Fixup CBO extension register calculation

[Alistair Francis]

When running the instruction

```
    cbo.flush 0(x0)
```

QEMU would segfault.

The issue was in cpu_gpr[a->rs1] as QEMU does not have cpu_gpr[0]
allocated.

In order to fix this let's use the existing get_address()
helper. This also has the benefit of performing pointer mask
calculations on the address specified in rs1.

The pointer masking specificiation specifically states:

"""
Cache Management Operations: All instructions in Zicbom, Zicbop and Zicboz
"""

So this is the correct behaviour and we previously have been incorrectly
not masking the address.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reported-by: Fabian Thomas <fabian.thomas@cispa.de>
Fixes: e05da09b7cfd ("target/riscv: implement Zicbom extension")
---
 target/riscv/insn_trans/trans_rvzicbo.c.inc | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/target/riscv/insn_trans/trans_rvzicbo.c.inc 
b/target/riscv/insn_trans/trans_rvzicbo.c.inc
index d5d7095903..15711c3140 100644
--- a/target/riscv/insn_trans/trans_rvzicbo.c.inc
+++ b/target/riscv/insn_trans/trans_rvzicbo.c.inc
@@ -31,27 +31,35 @@
 static bool trans_cbo_clean(DisasContext *ctx, arg_cbo_clean *a)
 {
     REQUIRE_ZICBOM(ctx);
-    gen_helper_cbo_clean_flush(tcg_env, cpu_gpr[a->rs1]);
+    TCGv src = get_address(ctx, a->rs1, 0);
+
+    gen_helper_cbo_clean_flush(tcg_env, src);
     return true;
 }
 
 static bool trans_cbo_flush(DisasContext *ctx, arg_cbo_flush *a)
 {
     REQUIRE_ZICBOM(ctx);
-    gen_helper_cbo_clean_flush(tcg_env, cpu_gpr[a->rs1]);
+    TCGv src = get_address(ctx, a->rs1, 0);
+
+    gen_helper_cbo_clean_flush(tcg_env, src);
     return true;
 }
 
 static bool trans_cbo_inval(DisasContext *ctx, arg_cbo_inval *a)
 {
     REQUIRE_ZICBOM(ctx);
-    gen_helper_cbo_inval(tcg_env, cpu_gpr[a->rs1]);
+    TCGv src = get_address(ctx, a->rs1, 0);
+
+    gen_helper_cbo_inval(tcg_env, src);
     return true;
 }
 
 static bool trans_cbo_zero(DisasContext *ctx, arg_cbo_zero *a)
 {
     REQUIRE_ZICBOZ(ctx);
-    gen_helper_cbo_zero(tcg_env, cpu_gpr[a->rs1]);
+    TCGv src = get_address(ctx, a->rs1, 0);
+
+    gen_helper_cbo_zero(tcg_env, src);
     return true;
 }
-- 
2.45.0