[prim/security] Improve the code for prim_sparse_fsm security check
According to the discussion in PR #11129, we update the enum checks from
generate block to a function.
JasperGold does support simple function syntax.
Signed-off-by: Cindy Chen <chencindy@opentitan.org>
diff --git a/hw/ip/prim/rtl/prim_assert_sec_cm.svh b/hw/ip/prim/rtl/prim_assert_sec_cm.svh
index bcc72d6..9fbbf94 100644
--- a/hw/ip/prim/rtl/prim_assert_sec_cm.svh
+++ b/hw/ip/prim/rtl/prim_assert_sec_cm.svh
@@ -24,6 +24,6 @@
`ASSERT_ERROR_TRIGGER_ALERT(NAME_, PRIM_HIER_, ALERT_, MAX_CYCLES_, err_o)
`define ASSERT_PRIM_FSM_ERROR_TRIGGER_ALERT(NAME_, PRIM_HIER_, ALERT_, MAX_CYCLES_ = 7) \
- `ASSERT_ERROR_TRIGGER_ALERT(NAME_, PRIM_HIER_, ALERT_, MAX_CYCLES_, unused_valid_st)
+ `ASSERT_ERROR_TRIGGER_ALERT(NAME_, PRIM_HIER_, ALERT_, MAX_CYCLES_, unused_err_o)
`endif // PRIM_ASSERT_SEC_CM_SVH
diff --git a/hw/ip/prim/rtl/prim_sparse_fsm_flop.sv b/hw/ip/prim/rtl/prim_sparse_fsm_flop.sv
index 830cedd..a327457 100644
--- a/hw/ip/prim/rtl/prim_sparse_fsm_flop.sv
+++ b/hw/ip/prim/rtl/prim_sparse_fsm_flop.sv
@@ -18,7 +18,7 @@
output logic [Width-1:0] state_o
);
- logic unused_valid_st;
+ logic unused_err_o;
prim_flop #(
.Width(Width),
@@ -31,21 +31,17 @@
);
`ifdef INC_ASSERT
- StateEnumT tmp = tmp.first;
- // An array to hold all possible enum values based on the given width.
- StateEnumT declared_fsms [2**Width];
+ assign unused_err_o = is_undefined_state(state_o);
- // Loop through all possible FSM values and store the listed StateEnumT enum value in
- // `declared_fsms`.
- // Ideally we can use `i < tmp.num`, but Xcelium does not support this syntax. (error msg:
- // Hierarchical name ('tmp.num()') not allowed within a constant expression)
- for (genvar i = 0; i < 2**Width; i++) begin : gen_declared_enum_list
- if (i == 0) assign declared_fsms[0] = tmp;
- else assign declared_fsms[i] = declared_fsms[i-1].next;
+ function automatic logic is_undefined_state(logic [Width-1:0] sig);
+ for (int i = 0, StateEnumT t = t.first(); i < t.num(); i += 1, t = t.next()) begin
+ if (StateEnumT'(sig) === t) return 0;
end
- assign unused_valid_st = !(state_o inside {declared_fsms});
+ return 1;
+ endfunction
+
`else
- assign unused_valid_st = 1'b1;
+ assign unused_err_o = 1'b0;
`endif
// If ASSERT_PRIM_FSM_ERROR_TRIGGER_ALERT is declared, the unused_assert_connected signal will
