zicfiss has following instructions
- sspopchk: pops a value from shadow stack and compares with x1/x5.
If they dont match, reports a sw check exception with tval = 3.
- sspush: pushes value in x1/x5 on shadow stack
- ssrdp: reads current shadow stack
- ssamoswap: swaps contents of shadow stack atomically
sspopchk/sspush/ssrdp default to zimop if zimop implemented and SSE=0
If SSE=0, ssamoswap is illegal instruction exception.
This patch implements shadow stack operations for qemu-user and shadow
stack is not protected.
Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Co-developed-by: Jim Shu <jim.shu@sifive.com>
Co-developed-by: Andy Chiu <andy.chiu@sifive.com>
---
target/riscv/cpu_bits.h | 2 ++
target/riscv/helper.h | 2 ++
target/riscv/insn32.decode | 17 +++++++--
target/riscv/insn_trans/trans_rva.c.inc | 47 +++++++++++++++++++++++++
target/riscv/op_helper.c | 9 +++++
target/riscv/translate.c | 1 +
6 files changed, 76 insertions(+), 2 deletions(-)
diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index 589326e516..8e179d6965 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -696,6 +696,8 @@ typedef enum RISCVException {
/* zicfilp defines lp violation results in sw check with tval = 2*/
#define RISCV_EXCP_SW_CHECK_FCFI_TVAL 2
+/* zicfiss defines ss violation results in sw check with tval = 3*/
+#define RISCV_EXCP_SW_CHECK_BCFI_TVAL 3
#define RISCV_EXCP_INT_FLAG 0x80000000
#define RISCV_EXCP_INT_MASK 0x7fffffff
diff --git a/target/riscv/helper.h b/target/riscv/helper.h
index ab55bbbf73..4efb7ba4df 100644
--- a/target/riscv/helper.h
+++ b/target/riscv/helper.h
@@ -124,6 +124,8 @@ DEF_HELPER_2(cbo_zero, void, env, tl)
/* Forward CFI label checking */
DEF_HELPER_2(cfi_jalr, void, env, int)
DEF_HELPER_2(cfi_check_landing_pad, void, env, int)
+/* helper for sschk mismatch (zicfiss) */
+DEF_HELPER_3(sschk_mismatch, void, env, tl, tl)
/* Special functions */
DEF_HELPER_2(csrr, tl, env, int)
diff --git a/target/riscv/insn32.decode b/target/riscv/insn32.decode
index c963c59c8e..c59c992ce2 100644
--- a/target/riscv/insn32.decode
+++ b/target/riscv/insn32.decode
@@ -65,8 +65,10 @@
# Formats 32:
@r ....... ..... ..... ... ..... ....... &r %rs2 %rs1 %rd
@i ............ ..... ... ..... ....... &i imm=%imm_i %rs1 %rd
+@ss_pop ............ ..... ... ..... ....... &i imm=0 %rs1 rd=0
@b ....... ..... ..... ... ..... ....... &b imm=%imm_b %rs2 %rs1
@s ....... ..... ..... ... ..... ....... &s imm=%imm_s %rs2 %rs1
+@ss_push ....... ..... ..... ... ..... ....... &s imm=0 %rs2 rs1=0
@u .................... ..... ....... &u imm=%imm_u %rd
@j .................... ..... ....... &j imm=%imm_j %rd
@@ -247,6 +249,7 @@ remud 0000001 ..... ..... 111 ..... 1111011 @r
lr_w 00010 . . 00000 ..... 010 ..... 0101111 @atom_ld
sc_w 00011 . . ..... ..... 010 ..... 0101111 @atom_st
amoswap_w 00001 . . ..... ..... 010 ..... 0101111 @atom_st
+ssamoswap_w 01001 . . ..... ..... 010 ..... 0101111 @atom_st
amoadd_w 00000 . . ..... ..... 010 ..... 0101111 @atom_st
amoxor_w 00100 . . ..... ..... 010 ..... 0101111 @atom_st
amoand_w 01100 . . ..... ..... 010 ..... 0101111 @atom_st
@@ -260,6 +263,7 @@ amomaxu_w 11100 . . ..... ..... 010 ..... 0101111 @atom_st
lr_d 00010 . . 00000 ..... 011 ..... 0101111 @atom_ld
sc_d 00011 . . ..... ..... 011 ..... 0101111 @atom_st
amoswap_d 00001 . . ..... ..... 011 ..... 0101111 @atom_st
+ssamoswap_d 01001 . . ..... ..... 011 ..... 0101111 @atom_st
amoadd_d 00000 . . ..... ..... 011 ..... 0101111 @atom_st
amoxor_d 00100 . . ..... ..... 011 ..... 0101111 @atom_st
amoand_d 01100 . . ..... ..... 011 ..... 0101111 @atom_st
@@ -1023,8 +1027,17 @@ amocas_d 00101 . . ..... ..... 011 ..... 0101111 @atom_st
amocas_q 00101 . . ..... ..... 100 ..... 0101111 @atom_st
# *** Zimop may-be-operation extension ***
-mop_r_n 1 . 00 .. 0111 .. ..... 100 ..... 1110011 @mop5
-mop_rr_n 1 . 00 .. 1 ..... ..... 100 ..... 1110011 @mop3
+{
+ # zicfiss instructions carved out of mop.r
+ ssrdp 1100110 11100 00000 100 ..... 1110011 %rd
+ sspopchk 1100110 11100 ..... 100 00000 1110011 @ss_pop
+ mop_r_n 1 . 00 .. 0111 .. ..... 100 ..... 1110011 @mop5
+}
+{
+ # zicfiss instruction carved out of mop.rr
+ sspush 1100111 ..... 00000 100 00000 1110011 @ss_push
+ mop_rr_n 1 . 00 .. 1 ..... ..... 100 ..... 1110011 @mop3
+}
# *** Zabhb Standard Extension ***
amoswap_b 00001 . . ..... ..... 000 ..... 0101111 @atom_st
diff --git a/target/riscv/insn_trans/trans_rva.c.inc b/target/riscv/insn_trans/trans_rva.c.inc
index 39bbf60f3c..db6c03f6a8 100644
--- a/target/riscv/insn_trans/trans_rva.c.inc
+++ b/target/riscv/insn_trans/trans_rva.c.inc
@@ -18,6 +18,8 @@
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include "exec/memop.h"
+
#define REQUIRE_A_OR_ZAAMO(ctx) do { \
if (!ctx->cfg_ptr->ext_zaamo && !has_ext(ctx, RVA)) { \
return false; \
@@ -114,6 +116,28 @@ static bool trans_amoswap_w(DisasContext *ctx, arg_amoswap_w *a)
return gen_amo(ctx, a, &tcg_gen_atomic_xchg_tl, MO_TESL);
}
+static bool trans_ssamoswap_w(DisasContext *ctx, arg_amoswap_w *a)
+{
+ REQUIRE_A_OR_ZAAMO(ctx);
+ /* default for qemu-user, use regular RW memory and thus mmu_idx=0 */
+ int ss_mmu_idx = 0;
+
+ /* back cfi was not enabled, return false */
+ if (!ctx->bcfi_enabled) {
+ return false;
+ }
+
+ TCGv dest = dest_gpr(ctx, a->rd);
+ TCGv src1, src2 = get_gpr(ctx, a->rs2, EXT_NONE);
+
+ decode_save_opc(ctx);
+ src1 = get_address(ctx, a->rs1, 0);
+
+ tcg_gen_atomic_xchg_tl(dest, src1, src2, ss_mmu_idx, (MO_ALIGN | MO_TESL));
+ gen_set_gpr(ctx, a->rd, dest);
+ return true;
+}
+
static bool trans_amoadd_w(DisasContext *ctx, arg_amoadd_w *a)
{
REQUIRE_A_OR_ZAAMO(ctx);
@@ -183,6 +207,29 @@ static bool trans_amoswap_d(DisasContext *ctx, arg_amoswap_d *a)
return gen_amo(ctx, a, &tcg_gen_atomic_xchg_tl, MO_TEUQ);
}
+static bool trans_ssamoswap_d(DisasContext *ctx, arg_amoswap_w *a)
+{
+ REQUIRE_64BIT(ctx);
+ REQUIRE_A_OR_ZAAMO(ctx);
+ /* default for qemu-user, use regular RW memory and thus mmu_idx=0 */
+ int ss_mmu_idx = 0;
+
+ /* back cfi was not enabled, return false */
+ if (!ctx->bcfi_enabled) {
+ return false;
+ }
+
+ TCGv dest = dest_gpr(ctx, a->rd);
+ TCGv src1, src2 = get_gpr(ctx, a->rs2, EXT_NONE);
+
+ decode_save_opc(ctx);
+ src1 = get_address(ctx, a->rs1, 0);
+
+ tcg_gen_atomic_xchg_tl(dest, src1, src2, ss_mmu_idx, (MO_ALIGN | MO_TESQ));
+ gen_set_gpr(ctx, a->rd, dest);
+ return true;
+}
+
static bool trans_amoadd_d(DisasContext *ctx, arg_amoadd_d *a)
{
REQUIRE_64BIT(ctx);
diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
index 2d152f0a00..54baa3a966 100644
--- a/target/riscv/op_helper.c
+++ b/target/riscv/op_helper.c
@@ -291,6 +291,15 @@ void helper_cfi_check_landing_pad(CPURISCVState *env, int lbl)
}
}
+void helper_sschk_mismatch(CPURISCVState *env, target_ulong rs1,
+ target_ulong ssra)
+{
+ if (rs1 != ssra) {
+ env->sw_check_code = RISCV_EXCP_SW_CHECK_BCFI_TVAL;
+ riscv_raise_exception(env, RISCV_EXCP_SW_CHECK, GETPC());
+ }
+}
+
#ifndef CONFIG_USER_ONLY
target_ulong helper_sret(CPURISCVState *env)
diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index 34c9bf093d..9152a963ee 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -1143,6 +1143,7 @@ static uint32_t opcode_at(DisasContextBase *dcbase, target_ulong pc)
#include "insn_trans/trans_rvzawrs.c.inc"
#include "insn_trans/trans_rvzicbo.c.inc"
#include "insn_trans/trans_rvzimop.c.inc"
+#include "insn_trans/trans_rvzicfiss.c.inc"
#include "insn_trans/trans_rvzfa.c.inc"
#include "insn_trans/trans_rvzfh.c.inc"
#include "insn_trans/trans_rvk.c.inc"
--
2.44.0