target/riscv: Restrict mideleg/medeleg/medelegh access to S-mode harts

RISC-V Privileged Spec states:
"In harts with S-mode, the medeleg and mideleg registers must exist, and
setting a bit in medeleg or mideleg will delegate the corresponding trap
, when occurring in S-mode or U-mode, to the S-mode trap handler. In
harts without S-mode, the medeleg and mideleg registers should not
exist."

Add smode predicate to ensure these CSRs are only accessible when S-mode
is supported.

Reviewed-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Jay Chang <jay.chang@sifive.com>
Reviewed-by: Nutty Liu<liujingqi@lanxincomputing.com>
Message-ID: <20250701030021.99218-2-jay.chang@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 9bebfae3f031fe967eda4630f3f3107efc71b6c7..5a6de074867e0b2d0d6d46edb356a9aad032ba5a 100644 (file)
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -5862,8 +5862,8 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
                           NULL,                read_mstatus_i128           },
     [CSR_MISA]        = { "misa",       any,   read_misa,    write_misa,
                           NULL,                read_misa_i128              },
-    [CSR_MIDELEG]     = { "mideleg",    any,   NULL, NULL,   rmw_mideleg   },
-    [CSR_MEDELEG]     = { "medeleg",    any,   read_medeleg, write_medeleg },
+    [CSR_MIDELEG]     = { "mideleg",    smode,   NULL, NULL,   rmw_mideleg   },
+    [CSR_MEDELEG]     = { "medeleg",    smode,   read_medeleg, write_medeleg },
     [CSR_MIE]         = { "mie",        any,   NULL, NULL,   rmw_mie       },
     [CSR_MTVEC]       = { "mtvec",      any,   read_mtvec,   write_mtvec   },
     [CSR_MCOUNTEREN]  = { "mcounteren", umode, read_mcounteren,
@@ -5871,7 +5871,7 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
 
     [CSR_MSTATUSH]    = { "mstatush",   any32, read_mstatush,
                           write_mstatush                                   },
-    [CSR_MEDELEGH]    = { "medelegh",   any32, read_zero, write_ignore,
+    [CSR_MEDELEGH]    = { "medelegh",   smode32, read_zero, write_ignore,
                           .min_priv_ver = PRIV_VERSION_1_13_0              },
     [CSR_HEDELEGH]    = { "hedelegh",   hmode32, read_hedelegh, write_hedelegh,
                           .min_priv_ver = PRIV_VERSION_1_13_0              },