[PATCH v3 18/20] target/riscv: add trace-hooks for each case of sw-check exception

[Deepak Gupta <debug@rivosinc.com>]

Violations to control flow rules setup by zicfilp and zicfiss lead to
software check exceptions. To debug and fix such sw check issues in guest
, add trace-hooks for each case.

Signed-off-by: Jim Shu <jim.shu@sifive.com>
Signed-off-by: Deepak Gupta <debug@rivosinc.com>
---
 target/riscv/insn_trans/trans_rvi.c.inc |  6 ++++--
 target/riscv/op_helper.c                | 24 ++++++++++++++++++++++++
 target/riscv/trace-events               |  6 ++++++
 target/riscv/translate.c                |  2 +-
 4 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/target/riscv/insn_trans/trans_rvi.c.inc b/target/riscv/insn_trans/trans_rvi.c.inc
index cbd7d5c395..0f5d5def60 100644
--- a/target/riscv/insn_trans/trans_rvi.c.inc
+++ b/target/riscv/insn_trans/trans_rvi.c.inc
@@ -65,7 +65,8 @@ static bool trans_lpad(DisasContext *ctx, arg_lpad *a)
              */
             gen_helper_raise_sw_check_excep(tcg_env,
                 tcg_constant_tl(RISCV_EXCP_SW_CHECK_FCFI_TVAL),
-                tcg_constant_tl(MISALIGNED_LPAD), tcg_constant_tl(0));
+                tcg_constant_tl(MISALIGNED_LPAD),
+                tcg_constant_tl(ctx->base.pc_next));
             return true;
         }
     }
@@ -81,7 +82,8 @@ static bool trans_lpad(DisasContext *ctx, arg_lpad *a)
         tcg_gen_brcondi_tl(TCG_COND_EQ, tmp, a->imm_cfi20, skip);
         gen_helper_raise_sw_check_excep(tcg_env,
             tcg_constant_tl(RISCV_EXCP_SW_CHECK_FCFI_TVAL),
-            tcg_constant_tl(LABEL_MISMATCH_LPAD), tcg_constant_tl(0));
+            tcg_constant_tl(LABEL_MISMATCH_LPAD),
+            tcg_constant_tl(a->imm_cfi20));
         gen_set_label(skip);
     }
 
diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
index 3b47fb34ea..07990e6589 100644
--- a/target/riscv/op_helper.c
+++ b/target/riscv/op_helper.c
@@ -24,6 +24,7 @@
 #include "exec/exec-all.h"
 #include "exec/cpu_ldst.h"
 #include "exec/helper-proto.h"
+#include "trace.h"
 
 /* Exceptions processing helpers */
 G_NORETURN void riscv_raise_exception(CPURISCVState *env,
@@ -262,6 +263,29 @@ void helper_cbo_inval(CPURISCVState *env, target_ulong address)
 void helper_raise_sw_check_excep(CPURISCVState *env, target_ulong swcheck_code,
                                  target_ulong arg1, target_ulong arg2)
 {
+    switch (swcheck_code) {
+    case RISCV_EXCP_SW_CHECK_FCFI_TVAL:
+        switch (arg1) {
+        case MISSING_LPAD:
+            trace_zicfilp_missing_lpad_instr(arg2);
+            break;
+        case MISALIGNED_LPAD:
+            trace_zicfilp_unaligned_lpad_instr(arg2);
+            break;
+        case LABEL_MISMATCH_LPAD:
+            trace_zicfilp_lpad_reg_mismatch(arg2);
+            break;
+        }
+        break;
+    case RISCV_EXCP_SW_CHECK_BCFI_TVAL:
+        trace_zicfiss_sspopchk_reg_mismatch(arg1, arg2);
+        break;
+    default:
+        /* any other value of swcheck_code is asserted */
+        assert(swcheck_code || (swcheck_code == 0));
+        break;
+    }
+
     env->sw_check_code = swcheck_code;
     riscv_raise_exception(env, RISCV_EXCP_SW_CHECK, GETPC());
 }
diff --git a/target/riscv/trace-events b/target/riscv/trace-events
index 49ec4d3b7d..0e8807f0d4 100644
--- a/target/riscv/trace-events
+++ b/target/riscv/trace-events
@@ -9,3 +9,9 @@ pmpaddr_csr_write(uint64_t mhartid, uint32_t addr_index, uint64_t val) "hart %"
 
 mseccfg_csr_read(uint64_t mhartid, uint64_t val) "hart %" PRIu64 ": read mseccfg, val: 0x%" PRIx64
 mseccfg_csr_write(uint64_t mhartid, uint64_t val) "hart %" PRIu64 ": write mseccfg, val: 0x%" PRIx64
+
+# zicfiss/lp
+zicfiss_sspopchk_reg_mismatch(uint64_t ssra, uint64_t rs1) "shadow_stack_ra: 0x%" PRIx64 ", rs1: 0x%" PRIx64
+zicfilp_missing_lpad_instr(uint64_t pc_first) "pc_first: 0x%" PRIx64
+zicfilp_unaligned_lpad_instr(uint64_t pc_next) "pc_next: 0x%" PRIx64
+zicfilp_lpad_reg_mismatch(int lpad_label) "lpad_label: 0x%x"
diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index 4772191bd8..9ef1f220e0 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -1302,7 +1302,7 @@ static void riscv_tr_tb_start(DisasContextBase *db, CPUState *cpu)
         tcg_gen_brcondi_i32(TCG_COND_EQ, immediate, 0, l);
         gen_helper_raise_sw_check_excep(tcg_env,
             tcg_constant_tl(RISCV_EXCP_SW_CHECK_FCFI_TVAL),
-            tcg_constant_tl(MISSING_LPAD), tcg_constant_tl(0));
+            tcg_constant_tl(MISSING_LPAD), tcg_constant_tl(ctx->base.pc_first));
         gen_set_label(l);
         /*
          * Despite the use of gen_exception_illegal(), the rest of
-- 
2.44.0