target/riscv: change RISCV_EXCP_SEMIHOST exception number to 63

The current semihost exception number (16) is a reserved number (range
[16-17]). The upcoming double trap specification uses that number for
the double trap exception. Since the privileged spec (Table 22) defines
ranges for custom uses change the semihosting exception number to 63
which belongs to the range [48-63] in order to avoid any future
collisions with reserved exception.

Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240422135840.1959967-1-cleger@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index fc2068ee4dcf725bc36b57f0014a95e3cbef39de..74318a925cabccfc6ebdb4397dede7783e6ff122 100644 (file)
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -670,11 +670,11 @@ typedef enum RISCVException {
     RISCV_EXCP_INST_PAGE_FAULT = 0xc, /* since: priv-1.10.0 */
     RISCV_EXCP_LOAD_PAGE_FAULT = 0xd, /* since: priv-1.10.0 */
     RISCV_EXCP_STORE_PAGE_FAULT = 0xf, /* since: priv-1.10.0 */
-    RISCV_EXCP_SEMIHOST = 0x10,
     RISCV_EXCP_INST_GUEST_PAGE_FAULT = 0x14,
     RISCV_EXCP_LOAD_GUEST_ACCESS_FAULT = 0x15,
     RISCV_EXCP_VIRT_INSTRUCTION_FAULT = 0x16,
     RISCV_EXCP_STORE_GUEST_AMO_ACCESS_FAULT = 0x17,
+    RISCV_EXCP_SEMIHOST = 0x3f,
 } RISCVException;
 
 #define RISCV_EXCP_INT_FLAG                0x80000000