target/riscv: th: make CSR insertion test a bit more intuitive

In preparation for generalizing the custom CSR functionality,
make the test return bool instead of int.  Make the insertion_test
optional, too.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/target/riscv/th_csr.c b/target/riscv/th_csr.c
index 6c970d4e813095cf0673f1c73ea9a5135c795daf..969a9fe3c802be816b678595774cf4fcf4f67de1 100644 (file)
--- a/target/riscv/th_csr.c
+++ b/target/riscv/th_csr.c
@@ -29,7 +29,7 @@
 
 typedef struct {
     int csrno;
-    int (*insertion_test)(RISCVCPU *cpu);
+    bool (*insertion_test)(RISCVCPU *cpu);
     riscv_csr_operations csr_ops;
 } riscv_csr;
 
@@ -42,13 +42,9 @@ static RISCVException smode(CPURISCVState *env, int csrno)
     return RISCV_EXCP_ILLEGAL_INST;
 }
 
-static int test_thead_mvendorid(RISCVCPU *cpu)
+static bool test_thead_mvendorid(RISCVCPU *cpu)
 {
-    if (cpu->cfg.mvendorid != THEAD_VENDOR_ID) {
-        return -1;
-    }
-
-    return 0;
+    return cpu->cfg.mvendorid == THEAD_VENDOR_ID;
 }
 
 static RISCVException read_th_sxstatus(CPURISCVState *env, int csrno,
@@ -66,13 +62,12 @@ static riscv_csr th_csr_list[] = {
         .csr_ops = { "th.sxstatus", smode, read_th_sxstatus }
     }
 };
-
 void th_register_custom_csrs(RISCVCPU *cpu)
 {
     for (size_t i = 0; i < ARRAY_SIZE(th_csr_list); i++) {
         int csrno = th_csr_list[i].csrno;
         riscv_csr_operations *csr_ops = &th_csr_list[i].csr_ops;
-        if (!th_csr_list[i].insertion_test(cpu)) {
+        if (!th_csr_list[i].insertion_test || th_csr_list[i].insertion_test(cpu)) {
             riscv_set_csr_ops(csrno, csr_ops);
         }
     }