target/riscv: Add x-zba, x-zbb, x-zbc and x-zbs properties

The bitmanipulation ISA extensions will be ratified as individual
small extension packages instead of a large B-extension.  The first
new instructions through the door (these have completed public review)
are Zb[abcs].

This adds new 'x-zba', 'x-zbb', 'x-zbc' and 'x-zbs' properties for
these in target/riscv/cpu.[ch].

Signed-off-by: Philipp Tomsich <philipp.tomsich@vrull.eu>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Message-id: 20210911140016.834071-5-philipp.tomsich@vrull.eu
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.c

@@ -617,6 +617,10 @@ static Property riscv_cpu_properties[] = {
     DEFINE_PROP_BOOL("u", RISCVCPU, cfg.ext_u, true),
     /* This is experimental so mark with 'x-' */
     DEFINE_PROP_BOOL("x-b", RISCVCPU, cfg.ext_b, false),
+    DEFINE_PROP_BOOL("x-zba", RISCVCPU, cfg.ext_zba, false),
+    DEFINE_PROP_BOOL("x-zbb", RISCVCPU, cfg.ext_zbb, false),
+    DEFINE_PROP_BOOL("x-zbc", RISCVCPU, cfg.ext_zbc, false),
+    DEFINE_PROP_BOOL("x-zbs", RISCVCPU, cfg.ext_zbs, false),
     DEFINE_PROP_BOOL("x-h", RISCVCPU, cfg.ext_h, false),
     DEFINE_PROP_BOOL("x-v", RISCVCPU, cfg.ext_v, false),
     DEFINE_PROP_BOOL("Counters", RISCVCPU, cfg.ext_counters, true),

target/riscv/cpu.h

@@ -293,6 +293,10 @@ struct RISCVCPU {
         bool ext_u;
         bool ext_h;
         bool ext_v;
+        bool ext_zba;
+        bool ext_zbb;
+        bool ext_zbc;
+        bool ext_zbs;
         bool ext_counters;
         bool ext_ifencei;
         bool ext_icsr;