From: Deepak Gupta <de...@rivosinc.com>
Commit f06bfe3dc38c ("target/riscv: implement zicfiss instructions") adds
`ssamoswap` instruction. `ssamoswap` takes the code-point from existing
reserved encoding (and not a zimop like other shadow stack instructions).
If shadow stack is not enabled (via xenvcfg.SSE) and effective priv is
less than M then `ssamoswap` must result in an illegal instruction
exception. However if effective priv is M, then `ssamoswap` results in
store/AMO access fault. See Section "22.2.3. Shadow Stack Memory
Protection" of priv spec.
Fixes: f06bfe3dc38c ("target/riscv: implement zicfiss instructions")
Reported-by: Ved Shanbhogue <v...@rivosinc.com>
Signed-off-by: Deepak Gupta <de...@rivosinc.com>
Reviewed-by: Alistair Francis <alistair.fran...@wdc.com>
Message-ID: <20250306064636.452396-2-de...@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.fran...@wdc.com>
(cherry picked from commit d2c5759c8dd4c00195d4ebecc7d009e41df6baef)
Signed-off-by: Michael Tokarev <m...@tls.msk.ru>
diff --git a/target/riscv/insn_trans/trans_rvzicfiss.c.inc
b/target/riscv/insn_trans/trans_rvzicfiss.c.inc
index e3ebc4977c..b0096adcd0 100644
--- a/target/riscv/insn_trans/trans_rvzicfiss.c.inc
+++ b/target/riscv/insn_trans/trans_rvzicfiss.c.inc
@@ -15,6 +15,13 @@
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
+
+#define REQUIRE_ZICFISS(ctx) do { \
+ if (!ctx->cfg_ptr->ext_zicfiss) { \
+ return false; \
+ } \
+} while (0)
+
static bool trans_sspopchk(DisasContext *ctx, arg_sspopchk *a)
{
if (!ctx->bcfi_enabled) {
@@ -77,6 +84,11 @@ static bool trans_ssrdp(DisasContext *ctx, arg_ssrdp *a)
static bool trans_ssamoswap_w(DisasContext *ctx, arg_amoswap_w *a)
{
REQUIRE_A_OR_ZAAMO(ctx);
+ REQUIRE_ZICFISS(ctx);
+ if (ctx->priv == PRV_M) {
+ generate_exception(ctx, RISCV_EXCP_STORE_AMO_ACCESS_FAULT);
+ }
+
if (!ctx->bcfi_enabled) {
return false;
}
@@ -97,6 +109,11 @@ static bool trans_ssamoswap_d(DisasContext *ctx,
arg_amoswap_w *a)
{
REQUIRE_64BIT(ctx);
REQUIRE_A_OR_ZAAMO(ctx);
+ REQUIRE_ZICFISS(ctx);
+ if (ctx->priv == PRV_M) {
+ generate_exception(ctx, RISCV_EXCP_STORE_AMO_ACCESS_FAULT);
+ }
+
if (!ctx->bcfi_enabled) {
return false;
}
--
2.39.5
