[PATCH v3 4/6] target/riscv: Add support to record CTR entries.

Rajnesh Kanwal posted 6 patches 2 weeks, 4 days ago
[PATCH v3 4/6] target/riscv: Add support to record CTR entries.
Posted by Rajnesh Kanwal 2 weeks, 4 days ago
This commit adds logic to records CTR entries of different types
and adds required hooks in TCG and interrupt/Exception logic to
record events.

This commit also adds support to invoke freeze CTR logic for breakpoint
exceptions and counter overflow interrupts.

Signed-off-by: Rajnesh Kanwal <rkanwal@rivosinc.com>
---
 target/riscv/cpu.h                             |   7 +
 target/riscv/cpu_helper.c                      | 259 +++++++++++++++++++++++++
 target/riscv/helper.h                          |   8 +-
 target/riscv/insn_trans/trans_privileged.c.inc |   6 +-
 target/riscv/insn_trans/trans_rvi.c.inc        |  31 +++
 target/riscv/insn_trans/trans_rvzce.c.inc      |  20 ++
 target/riscv/op_helper.c                       | 126 +++++++++++-
 target/riscv/translate.c                       |  10 +
 8 files changed, 461 insertions(+), 6 deletions(-)

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 0ffe0d5a74aa699fc34453e072bed27001819a5e..189dba78970c414bff8aa252507c4585844bd846 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -310,6 +310,10 @@ struct CPUArchState {
     uint32_t sctrstatus;
     uint64_t vsctrctl;
 
+    uint64_t ctr_src[16 << SCTRDEPTH_MAX];
+    uint64_t ctr_dst[16 << SCTRDEPTH_MAX];
+    uint64_t ctr_data[16 << SCTRDEPTH_MAX];
+
     /* Machine and Supervisor interrupt priorities */
     uint8_t miprio[64];
     uint8_t siprio[64];
@@ -608,6 +612,9 @@ RISCVException smstateen_acc_ok(CPURISCVState *env, int index, uint64_t bit);
 
 void riscv_cpu_set_mode(CPURISCVState *env, target_ulong newpriv, bool virt_en);
 
+void riscv_ctr_add_entry(CPURISCVState *env, target_long src, target_long dst,
+    enum CTRType type, target_ulong prev_priv, bool prev_virt);
+
 void riscv_translate_init(void);
 G_NORETURN void riscv_raise_exception(CPURISCVState *env,
                                       uint32_t exception, uintptr_t pc);
diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 395a1d9140615d697408054ed680ad1f9b26a83e..06defc870cf85ed7c646ca6b066ce556bab1e757 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -691,6 +691,247 @@ void riscv_cpu_set_aia_ireg_rmw_fn(CPURISCVState *env, uint32_t priv,
     }
 }
 
+static void riscv_ctr_freeze(CPURISCVState *env, uint64_t freeze_mask,
+                             bool virt)
+{
+    uint64_t ctl = virt ? env->vsctrctl : env->mctrctl;
+
+    assert((freeze_mask & (~(XCTRCTL_BPFRZ | XCTRCTL_LCOFIFRZ))) == 0);
+
+    if (ctl & freeze_mask) {
+        env->sctrstatus |= SCTRSTATUS_FROZEN;
+    }
+}
+
+static uint64_t riscv_ctr_priv_to_mask(target_ulong priv, bool virt)
+{
+    switch (priv) {
+    case PRV_M:
+        return MCTRCTL_M;
+    case PRV_S:
+        if (virt) {
+            return XCTRCTL_S;
+        }
+        return XCTRCTL_S;
+    case PRV_U:
+        if (virt) {
+            return XCTRCTL_U;
+        }
+        return XCTRCTL_U;
+    }
+
+    g_assert_not_reached();
+}
+
+static uint64_t riscv_ctr_get_control(CPURISCVState *env, target_long priv,
+                                      bool virt)
+{
+    switch (priv) {
+    case PRV_M:
+        return env->mctrctl;
+    case PRV_S:
+    case PRV_U:
+        if (virt) {
+            return env->vsctrctl;
+        }
+        return env->mctrctl;
+    }
+
+    g_assert_not_reached();
+}
+
+/*
+ * This function assumes that src privilege and target privilege are not same
+ * and src privilege is less than target privilege. This includes the virtual
+ * state as well.
+ */
+static bool riscv_ctr_check_xte(CPURISCVState *env, target_long src_prv,
+                                bool src_virt)
+{
+    target_long tgt_prv = env->priv;
+    bool res = true;
+
+    /*
+     * VS and U mode are same in terms of xTE bits required to record an
+     * external trap. See 6.1.2. External Traps, table 8 External Trap Enable
+     * Requirements. This changes VS to U to simplify the logic a bit.
+     */
+    if (src_virt && src_prv == PRV_S) {
+        src_prv = PRV_U;
+    } else if (env->virt_enabled && tgt_prv == PRV_S) {
+        tgt_prv = PRV_U;
+    }
+
+    /* VU mode is an outlier here. */
+    if (src_virt && src_prv == PRV_U) {
+        res &= !!(env->vsctrctl & XCTRCTL_STE);
+    }
+
+    switch (src_prv) {
+    case PRV_U:
+        if (tgt_prv == PRV_U) {
+            break;
+        }
+        res &= !!(env->mctrctl & XCTRCTL_STE);
+        /* fall-through */
+    case PRV_S:
+        if (tgt_prv == PRV_S) {
+            break;
+        }
+        res &= !!(env->mctrctl & MCTRCTL_MTE);
+        /* fall-through */
+    case PRV_M:
+        break;
+    }
+
+    return res;
+}
+
+/*
+ * Special cases for traps and trap returns:
+ *
+ * 1- Traps, and trap returns, between enabled modes are recorded as normal.
+ * 2- Traps from an inhibited mode to an enabled mode, and trap returns from an
+ * enabled mode back to an inhibited mode, are partially recorded.  In such
+ * cases, the PC from the inhibited mode (source PC for traps, and target PC
+ * for trap returns) is 0.
+ *
+ * 3- Trap returns from an inhibited mode to an enabled mode are not recorded.
+ * Traps from an enabled mode to an inhibited mode, known as external traps,
+ * receive special handling.
+ * By default external traps are not recorded, but a handshake mechanism exists
+ * to allow partial recording.  Software running in the target mode of the trap
+ * can opt-in to allowing CTR to record traps into that mode even when the mode
+ * is inhibited.  The MTE, STE, and VSTE bits allow M-mode, S-mode, and VS-mode,
+ * respectively, to opt-in. When an External Trap occurs, and xTE=1, such that
+ * x is the target privilege mode of the trap, will CTR record the trap. In such
+ * cases, the target PC is 0.
+ */
+/*
+ * CTR arrays are implemented as circular buffers and new entry is stored at
+ * sctrstatus.WRPTR, but they are presented to software as moving circular
+ * buffers. Which means, software get's the illusion that whenever a new entry
+ * is added the whole buffer is moved by one place and the new entry is added at
+ * the start keeping new entry at idx 0 and older ones follow.
+ *
+ * Depth = 16.
+ *
+ * buffer [0] [1] [2] [3] [4] [5] [6] [7] [8] [9] [A] [B] [C] [D] [E] [F]
+ * WRPTR                                   W
+ * entry   7   6   5   4   3   2   1   0   F   E   D   C   B   A   9   8
+ *
+ * When a new entry is added:
+ * buffer [0] [1] [2] [3] [4] [5] [6] [7] [8] [9] [A] [B] [C] [D] [E] [F]
+ * WRPTR                                       W
+ * entry   8   7   6   5   4   3   2   1   0   F   E   D   C   B   A   9
+ *
+ * entry here denotes the logical entry number that software can access
+ * using ctrsource, ctrtarget and ctrdata registers. So xiselect 0x200
+ * will return entry 0 i-e buffer[8] and 0x201 will return entry 1 i-e
+ * buffer[7]. Here is how we convert entry to buffer idx.
+ *
+ *    entry = isel - CTR_ENTRIES_FIRST;
+ *    idx = (sctrstatus.WRPTR - entry - 1) & (depth - 1);
+ */
+void riscv_ctr_add_entry(CPURISCVState *env, target_long src, target_long dst,
+    enum CTRType type, target_ulong src_priv, bool src_virt)
+{
+    bool tgt_virt = env->virt_enabled;
+    uint64_t src_mask = riscv_ctr_priv_to_mask(src_priv, src_virt);
+    uint64_t tgt_mask = riscv_ctr_priv_to_mask(env->priv, tgt_virt);
+    uint64_t src_ctrl = riscv_ctr_get_control(env, src_priv, src_virt);
+    uint64_t tgt_ctrl = riscv_ctr_get_control(env, env->priv, tgt_virt);
+    uint64_t depth, head;
+    bool ext_trap = false;
+
+    /*
+     * Return immediately if both target and src recording is disabled or if
+     * CTR is in frozen state.
+     */
+    if ((!(src_ctrl & src_mask) && !(tgt_ctrl & tgt_mask)) ||
+        env->sctrstatus & SCTRSTATUS_FROZEN) {
+        return;
+    }
+
+    /*
+     * With RAS Emul enabled, only allow Indirect, direct calls, Function
+     * returns and Co-routine swap types.
+     */
+    if (tgt_ctrl & XCTRCTL_RASEMU &&
+        type != CTRDATA_TYPE_INDIRECT_CALL &&
+        type != CTRDATA_TYPE_DIRECT_CALL &&
+        type != CTRDATA_TYPE_RETURN &&
+        type != CTRDATA_TYPE_CO_ROUTINE_SWAP) {
+        return;
+    }
+
+    if (type == CTRDATA_TYPE_EXCEPTION || type == CTRDATA_TYPE_INTERRUPT) {
+        /* Case 2 for traps. */
+        if (!(src_ctrl & src_mask)) {
+            src = 0;
+        } else if (!(tgt_ctrl & tgt_mask)) {
+            /* Check if target priv-mode has allowed external trap recording. */
+            if (!riscv_ctr_check_xte(env, src_priv, src_virt)) {
+                return;
+            }
+
+            ext_trap = true;
+            dst = 0;
+        }
+    } else if (type == CTRDATA_TYPE_EXCEP_INT_RET) {
+        /*
+         * Case 3 for trap returns.  Trap returns from inhibited mode are not
+         * recorded.
+         */
+        if (!(src_ctrl & src_mask)) {
+            return;
+        }
+
+        /* Case 2 for trap returns. */
+        if (!(tgt_ctrl & tgt_mask)) {
+            dst = 0;
+        }
+    }
+
+    /* Ignore filters in case of RASEMU mode or External trap. */
+    if (!(tgt_ctrl & XCTRCTL_RASEMU) && !ext_trap) {
+        /*
+         * Check if the specific type is inhibited. Not taken branch filter is
+         * an enable bit and needs to be checked separatly.
+         */
+        bool check = tgt_ctrl & BIT_ULL(type + XCTRCTL_INH_START);
+        if ((type == CTRDATA_TYPE_NONTAKEN_BRANCH && !check) ||
+            (type != CTRDATA_TYPE_NONTAKEN_BRANCH && check)) {
+            return;
+        }
+    }
+
+    head = get_field(env->sctrstatus, SCTRSTATUS_WRPTR_MASK);
+
+    depth = 16 << get_field(env->sctrdepth, SCTRDEPTH_MASK);
+    if (tgt_ctrl & XCTRCTL_RASEMU && type == CTRDATA_TYPE_RETURN) {
+        head = (head - 1) & (depth - 1);
+
+        env->ctr_src[head] &= ~CTRSOURCE_VALID;
+        env->sctrstatus =
+            set_field(env->sctrstatus, SCTRSTATUS_WRPTR_MASK, head);
+        return;
+    }
+
+    /* In case of Co-routine SWAP we overwrite latest entry. */
+    if (tgt_ctrl & XCTRCTL_RASEMU && type == CTRDATA_TYPE_CO_ROUTINE_SWAP) {
+        head = (head - 1) & (depth - 1);
+    }
+
+    env->ctr_src[head] = src | CTRSOURCE_VALID;
+    env->ctr_dst[head] = dst & ~CTRTARGET_MISP;
+    env->ctr_data[head] = set_field(0, CTRDATA_TYPE_MASK, type);
+
+    head = (head + 1) & (depth - 1);
+
+    env->sctrstatus = set_field(env->sctrstatus, SCTRSTATUS_WRPTR_MASK, head);
+}
+
 void riscv_cpu_set_mode(CPURISCVState *env, target_ulong newpriv, bool virt_en)
 {
     g_assert(newpriv <= PRV_M && newpriv != PRV_RESERVED);
@@ -1666,10 +1907,13 @@ void riscv_cpu_do_interrupt(CPUState *cs)
         !(env->mip & (1 << cause));
     bool vs_injected = env->hvip & (1 << cause) & env->hvien &&
         !(env->mip & (1 << cause));
+    const bool prev_virt = env->virt_enabled;
+    const target_ulong prev_priv = env->priv;
     target_ulong tval = 0;
     target_ulong tinst = 0;
     target_ulong htval = 0;
     target_ulong mtval2 = 0;
+    target_ulong src;
 
     if (!async) {
         /* set tval to badaddr for traps with address information */
@@ -1804,6 +2048,8 @@ void riscv_cpu_do_interrupt(CPUState *cs)
         env->pc = (env->stvec >> 2 << 2) +
                   ((async && (env->stvec & 3) == 1) ? cause * 4 : 0);
         riscv_cpu_set_mode(env, PRV_S, virt);
+
+        src = env->sepc;
     } else {
         /* handle the trap in M-mode */
         if (riscv_has_ext(env, RVH)) {
@@ -1835,6 +2081,19 @@ void riscv_cpu_do_interrupt(CPUState *cs)
         env->pc = (env->mtvec >> 2 << 2) +
                   ((async && (env->mtvec & 3) == 1) ? cause * 4 : 0);
         riscv_cpu_set_mode(env, PRV_M, virt);
+        src = env->mepc;
+    }
+
+    if (riscv_cpu_cfg(env)->ext_smctr || riscv_cpu_cfg(env)->ext_ssctr) {
+        if (async && cause == IRQ_PMU_OVF) {
+            riscv_ctr_freeze(env, XCTRCTL_LCOFIFRZ, virt);
+        } else if (!async && cause == RISCV_EXCP_BREAKPOINT) {
+            riscv_ctr_freeze(env, XCTRCTL_BPFRZ, virt);
+        }
+
+        riscv_ctr_add_entry(env, src, env->pc,
+                        async ? CTRDATA_TYPE_INTERRUPT : CTRDATA_TYPE_EXCEPTION,
+                        prev_priv, prev_virt);
     }
 
     /*
diff --git a/target/riscv/helper.h b/target/riscv/helper.h
index 451261ce5a4f6138a06afb1e4abc0c838acb283e..b8fb7c87348d1f850628ab3769afda08158739be 100644
--- a/target/riscv/helper.h
+++ b/target/riscv/helper.h
@@ -129,12 +129,16 @@ DEF_HELPER_2(csrr_i128, tl, env, int)
 DEF_HELPER_4(csrw_i128, void, env, int, tl, tl)
 DEF_HELPER_6(csrrw_i128, tl, env, int, tl, tl, tl, tl)
 #ifndef CONFIG_USER_ONLY
-DEF_HELPER_1(sret, tl, env)
-DEF_HELPER_1(mret, tl, env)
+DEF_HELPER_2(sret, tl, env, tl)
+DEF_HELPER_2(mret, tl, env, tl)
 DEF_HELPER_1(wfi, void, env)
 DEF_HELPER_1(wrs_nto, void, env)
 DEF_HELPER_1(tlb_flush, void, env)
 DEF_HELPER_1(tlb_flush_all, void, env)
+DEF_HELPER_4(ctr_branch, void, env, tl, tl, tl)
+DEF_HELPER_4(ctr_jal, void, env, tl, tl, tl)
+DEF_HELPER_5(ctr_jalr, void, env, tl, tl, tl, tl)
+DEF_HELPER_3(ctr_popret, void, env, tl, tl)
 /* Native Debug */
 DEF_HELPER_1(itrigger_match, void, env)
 #endif
diff --git a/target/riscv/insn_trans/trans_privileged.c.inc b/target/riscv/insn_trans/trans_privileged.c.inc
index 4eccdddeaaf0c242cf3b2c268bae3230126dbc7c..339d65915173482507849ad36ff4eb3d1403c148 100644
--- a/target/riscv/insn_trans/trans_privileged.c.inc
+++ b/target/riscv/insn_trans/trans_privileged.c.inc
@@ -78,9 +78,10 @@ static bool trans_sret(DisasContext *ctx, arg_sret *a)
 {
 #ifndef CONFIG_USER_ONLY
     if (has_ext(ctx, RVS)) {
+        TCGv src = tcg_constant_tl(ctx->base.pc_next);
         decode_save_opc(ctx);
         translator_io_start(&ctx->base);
-        gen_helper_sret(cpu_pc, tcg_env);
+        gen_helper_sret(cpu_pc, tcg_env, src);
         exit_tb(ctx); /* no chaining */
         ctx->base.is_jmp = DISAS_NORETURN;
     } else {
@@ -95,9 +96,10 @@ static bool trans_sret(DisasContext *ctx, arg_sret *a)
 static bool trans_mret(DisasContext *ctx, arg_mret *a)
 {
 #ifndef CONFIG_USER_ONLY
+    TCGv src = tcg_constant_tl(ctx->base.pc_next);
     decode_save_opc(ctx);
     translator_io_start(&ctx->base);
-    gen_helper_mret(cpu_pc, tcg_env);
+    gen_helper_mret(cpu_pc, tcg_env, src);
     exit_tb(ctx); /* no chaining */
     ctx->base.is_jmp = DISAS_NORETURN;
     return true;
diff --git a/target/riscv/insn_trans/trans_rvi.c.inc b/target/riscv/insn_trans/trans_rvi.c.inc
index 98e3806d5e5a31715981244ba48acf770e2b894b..54c304c63aececba4d5166a3e2ad3c6aa4d6ea8f 100644
--- a/target/riscv/insn_trans/trans_rvi.c.inc
+++ b/target/riscv/insn_trans/trans_rvi.c.inc
@@ -75,6 +75,14 @@ static bool trans_jalr(DisasContext *ctx, arg_jalr *a)
     gen_set_gpr(ctx, a->rd, succ_pc);
 
     tcg_gen_mov_tl(cpu_pc, target_pc);
+#ifndef CONFIG_USER_ONLY
+    if (ctx->cfg_ptr->ext_smctr || ctx->cfg_ptr->ext_ssctr) {
+        TCGv src = tcg_constant_tl(ctx->base.pc_next);
+        TCGv rs1 = tcg_constant_tl(a->rs1);
+        TCGv rd = tcg_constant_tl(a->rd);
+        gen_helper_ctr_jalr(tcg_env, src, cpu_pc, rd, rs1);
+    }
+#endif
     lookup_and_goto_ptr(ctx);
 
     if (misaligned) {
@@ -164,6 +172,11 @@ static bool gen_branch(DisasContext *ctx, arg_b *a, TCGCond cond)
     TCGv src1 = get_gpr(ctx, a->rs1, EXT_SIGN);
     TCGv src2 = get_gpr(ctx, a->rs2, EXT_SIGN);
     target_ulong orig_pc_save = ctx->pc_save;
+#ifndef CONFIG_USER_ONLY
+    TCGv src = tcg_constant_tl(ctx->base.pc_next);
+    TCGv taken;
+    TCGv dest;
+#endif
 
     if (get_xl(ctx) == MXL_RV128) {
         TCGv src1h = get_gprh(ctx, a->rs1);
@@ -176,6 +189,16 @@ static bool gen_branch(DisasContext *ctx, arg_b *a, TCGCond cond)
     } else {
         tcg_gen_brcond_tl(cond, src1, src2, l);
     }
+
+#ifndef CONFIG_USER_ONLY
+    if (ctx->cfg_ptr->ext_smctr || ctx->cfg_ptr->ext_ssctr) {
+        dest = tcg_constant_tl(ctx->base.pc_next + ctx->cur_insn_len);
+        taken = tcg_constant_tl(0);
+
+        gen_helper_ctr_branch(tcg_env, src, dest, taken);
+    }
+#endif
+
     gen_goto_tb(ctx, 1, ctx->cur_insn_len);
     ctx->pc_save = orig_pc_save;
 
@@ -188,6 +211,14 @@ static bool gen_branch(DisasContext *ctx, arg_b *a, TCGCond cond)
         gen_pc_plus_diff(target_pc, ctx, a->imm);
         gen_exception_inst_addr_mis(ctx, target_pc);
     } else {
+#ifndef CONFIG_USER_ONLY
+        if (ctx->cfg_ptr->ext_smctr || ctx->cfg_ptr->ext_ssctr) {
+            dest = tcg_constant_tl(ctx->base.pc_next + a->imm);
+            taken = tcg_constant_tl(1);
+
+            gen_helper_ctr_branch(tcg_env, src, dest, taken);
+        }
+#endif
         gen_goto_tb(ctx, 0, a->imm);
     }
     ctx->pc_save = -1;
diff --git a/target/riscv/insn_trans/trans_rvzce.c.inc b/target/riscv/insn_trans/trans_rvzce.c.inc
index cd234ad960724c936b92afb6fd1f3c7c2a37cb80..377d3fff70bcbd21199e485161d51c6ef31593c5 100644
--- a/target/riscv/insn_trans/trans_rvzce.c.inc
+++ b/target/riscv/insn_trans/trans_rvzce.c.inc
@@ -204,6 +204,12 @@ static bool gen_pop(DisasContext *ctx, arg_cmpp *a, bool ret, bool ret_val)
     if (ret) {
         TCGv ret_addr = get_gpr(ctx, xRA, EXT_SIGN);
         tcg_gen_mov_tl(cpu_pc, ret_addr);
+#ifndef CONFIG_USER_ONLY
+        if (ctx->cfg_ptr->ext_smctr || ctx->cfg_ptr->ext_ssctr) {
+            TCGv src = tcg_constant_tl(ctx->base.pc_next);
+            gen_helper_ctr_popret(tcg_env, src, cpu_pc);
+        }
+#endif
         tcg_gen_lookup_and_goto_ptr();
         ctx->base.is_jmp = DISAS_NORETURN;
     }
@@ -309,6 +315,20 @@ static bool trans_cm_jalt(DisasContext *ctx, arg_cm_jalt *a)
         gen_set_gpr(ctx, xRA, succ_pc);
     }
 
+#ifndef CONFIG_USER_ONLY
+    if (ctx->cfg_ptr->ext_smctr || ctx->cfg_ptr->ext_ssctr) {
+        /*
+         * We are reusing helper_ctr_jal() here. If rd is x1 or x5,
+         * this will record a direct call (cm.jalt) and if it's x0
+         * then this will record a direct jump (cm.jt).
+         */
+        TCGv rd = tcg_constant_tl(a->index >= 32 ? 1 : 0);
+        TCGv src = tcg_constant_tl(ctx->base.pc_next);
+        gen_helper_ctr_jal(tcg_env, src, addr, rd);
+    }
+#endif
+
+
     tcg_gen_mov_tl(cpu_pc, addr);
 
     tcg_gen_lookup_and_goto_ptr();
diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
index 25a5263573b94c064fea7b6ee71549db9777b59f..5a1e92c45ed108d038ad30f5c7031b05855ac110 100644
--- a/target/riscv/op_helper.c
+++ b/target/riscv/op_helper.c
@@ -259,10 +259,12 @@ void helper_cbo_inval(CPURISCVState *env, target_ulong address)
 
 #ifndef CONFIG_USER_ONLY
 
-target_ulong helper_sret(CPURISCVState *env)
+target_ulong helper_sret(CPURISCVState *env, target_ulong curr_pc)
 {
     uint64_t mstatus;
     target_ulong prev_priv, prev_virt = env->virt_enabled;
+    const target_ulong src_priv = env->priv;
+    const bool src_virt = env->virt_enabled;
 
     if (!(env->priv >= PRV_S)) {
         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
@@ -309,10 +311,15 @@ target_ulong helper_sret(CPURISCVState *env)
 
     riscv_cpu_set_mode(env, prev_priv, prev_virt);
 
+    if (riscv_cpu_cfg(env)->ext_smctr || riscv_cpu_cfg(env)->ext_ssctr) {
+        riscv_ctr_add_entry(env, curr_pc, retpc, CTRDATA_TYPE_EXCEP_INT_RET,
+                            src_priv, src_virt);
+    }
+
     return retpc;
 }
 
-target_ulong helper_mret(CPURISCVState *env)
+target_ulong helper_mret(CPURISCVState *env, target_ulong curr_pc)
 {
     if (!(env->priv >= PRV_M)) {
         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
@@ -350,9 +357,124 @@ target_ulong helper_mret(CPURISCVState *env)
 
     riscv_cpu_set_mode(env, prev_priv, prev_virt);
 
+    if (riscv_cpu_cfg(env)->ext_smctr || riscv_cpu_cfg(env)->ext_ssctr) {
+        riscv_ctr_add_entry(env, curr_pc, retpc, CTRDATA_TYPE_EXCEP_INT_RET,
+                            PRV_M, false);
+    }
+
     return retpc;
 }
 
+/*
+ * Indirect calls
+ * - jalr x1, rs where rs != x5;
+ * - jalr x5, rs where rs != x1;
+ * - c.jalr rs1 where rs1 != x5;
+ *
+ * Indirect jumps
+ * - jalr x0, rs where rs != x1 and rs != x5;
+ * - c.jr rs1 where rs1 != x1 and rs1 != x5.
+ *
+ * Returns
+ * - jalr rd, rs where (rs == x1 or rs == x5) and rd != x1 and rd != x5;
+ * - c.jr rs1 where rs1 == x1 or rs1 == x5.
+ *
+ * Co-routine swap
+ * - jalr x1, x5;
+ * - jalr x5, x1;
+ * - c.jalr x5.
+ *
+ * Other indirect jumps
+ * - jalr rd, rs where rs != x1, rs != x5, rd != x0, rd != x1 and rd != x5.
+ */
+void helper_ctr_jalr(CPURISCVState *env, target_ulong src, target_ulong dest,
+                     target_ulong rd, target_ulong rs1)
+{
+    target_ulong curr_priv = env->priv;
+    bool curr_virt = env->virt_enabled;
+
+    if ((rd == 1 && rs1 != 5) || (rd == 5 && rs1 != 1)) {
+        riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_INDIRECT_CALL,
+                            curr_priv, curr_virt);
+    } else if (rd == 0 && rs1 != 1 && rs1 != 5) {
+        riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_INDIRECT_JUMP,
+                            curr_priv, curr_virt);
+    } else if ((rs1 == 1 || rs1 == 5) && (rd != 1 && rd != 5)) {
+        riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_RETURN,
+                            curr_priv, curr_virt);
+    } else if ((rs1 == 1 && rd == 5) || (rs1 == 5 && rd == 1)) {
+        riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_CO_ROUTINE_SWAP,
+                            curr_priv, curr_virt);
+    } else {
+        riscv_ctr_add_entry(env, src, dest,
+                            CTRDATA_TYPE_OTHER_INDIRECT_JUMP, curr_priv,
+                            curr_virt);
+    }
+}
+
+/*
+ * Direct calls
+ * - jal x1;
+ * - jal x5;
+ * - c.jal.
+ * - cm.jalt.
+ *
+ * Direct jumps
+ * - jal x0;
+ * - c.j;
+ * - cm.jt.
+ *
+ * Other direct jumps
+ * - jal rd where rd != x1 and rd != x5 and rd != x0;
+ */
+void helper_ctr_jal(CPURISCVState *env, target_ulong src, target_ulong dest,
+                    target_ulong rd)
+{
+    target_ulong priv = env->priv;
+    bool virt = env->virt_enabled;
+
+    /*
+     * If rd is x1 or x5 link registers, treat this as direct call otherwise
+     * its a direct jump.
+     */
+    if (rd == 1 || rd == 5) {
+        riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_DIRECT_CALL, priv,
+                            virt);
+    } else if (rd == 0) {
+        riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_DIRECT_JUMP, priv,
+                            virt);
+    } else {
+        riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_OTHER_DIRECT_JUMP,
+                            priv, virt);
+    }
+}
+
+/*
+ * Returns
+ * - cm.popret
+ * - cm.popretz
+ */
+void helper_ctr_popret(CPURISCVState *env, target_ulong src, target_ulong dest)
+{
+    riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_RETURN,
+                            env->priv, env->virt_enabled);
+}
+
+void helper_ctr_branch(CPURISCVState *env, target_ulong src, target_ulong dest,
+                       target_ulong branch_taken)
+{
+    target_ulong curr_priv = env->priv;
+    bool curr_virt = env->virt_enabled;
+
+    if (branch_taken) {
+        riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_TAKEN_BRANCH,
+                            curr_priv, curr_virt);
+    } else {
+        riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_NONTAKEN_BRANCH,
+                            curr_priv, curr_virt);
+    }
+}
+
 void helper_wfi(CPURISCVState *env)
 {
     CPUState *cs = env_cpu(env);
diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index acba90f170257cec428bb117652f7ccbb6800c4d..f3ab07755cbcc2db7d225513d96353a6c179a985 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -569,6 +569,16 @@ static void gen_jal(DisasContext *ctx, int rd, target_ulong imm)
         }
     }
 
+#ifndef CONFIG_USER_ONLY
+    if (ctx->cfg_ptr->ext_smctr || ctx->cfg_ptr->ext_ssctr) {
+        TCGv dest = tcg_constant_tl(ctx->base.pc_next + imm);
+        TCGv src = tcg_constant_tl(ctx->base.pc_next);
+        TCGv tcg_rd = tcg_constant_tl((target_ulong)rd);
+
+        gen_helper_ctr_jal(tcg_env, src, dest, tcg_rd);
+    }
+#endif
+
     gen_pc_plus_diff(succ_pc, ctx, ctx->cur_insn_len);
     gen_set_gpr(ctx, rd, succ_pc);
 

-- 
2.34.1
Re: [PATCH v3 4/6] target/riscv: Add support to record CTR entries.
Posted by Richard Henderson 2 weeks, 4 days ago
On 11/4/24 21:51, Rajnesh Kanwal wrote:
> +/*
> + * Indirect calls
> + * - jalr x1, rs where rs != x5;
> + * - jalr x5, rs where rs != x1;
> + * - c.jalr rs1 where rs1 != x5;
> + *
> + * Indirect jumps
> + * - jalr x0, rs where rs != x1 and rs != x5;
> + * - c.jr rs1 where rs1 != x1 and rs1 != x5.
> + *
> + * Returns
> + * - jalr rd, rs where (rs == x1 or rs == x5) and rd != x1 and rd != x5;
> + * - c.jr rs1 where rs1 == x1 or rs1 == x5.
> + *
> + * Co-routine swap
> + * - jalr x1, x5;
> + * - jalr x5, x1;
> + * - c.jalr x5.
> + *
> + * Other indirect jumps
> + * - jalr rd, rs where rs != x1, rs != x5, rd != x0, rd != x1 and rd != x5.
> + */
> +void helper_ctr_jalr(CPURISCVState *env, target_ulong src, target_ulong dest,
> +                     target_ulong rd, target_ulong rs1)
> +{
> +    target_ulong curr_priv = env->priv;
> +    bool curr_virt = env->virt_enabled;
> +
> +    if ((rd == 1 && rs1 != 5) || (rd == 5 && rs1 != 1)) {
> +        riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_INDIRECT_CALL,
> +                            curr_priv, curr_virt);
> +    } else if (rd == 0 && rs1 != 1 && rs1 != 5) {
> +        riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_INDIRECT_JUMP,
> +                            curr_priv, curr_virt);
> +    } else if ((rs1 == 1 || rs1 == 5) && (rd != 1 && rd != 5)) {
> +        riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_RETURN,
> +                            curr_priv, curr_virt);
> +    } else if ((rs1 == 1 && rd == 5) || (rs1 == 5 && rd == 1)) {
> +        riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_CO_ROUTINE_SWAP,
> +                            curr_priv, curr_virt);
> +    } else {
> +        riscv_ctr_add_entry(env, src, dest,
> +                            CTRDATA_TYPE_OTHER_INDIRECT_JUMP, curr_priv,
> +                            curr_virt);
> +    }
> +}

All of these if's are constant at translation time.
You should move this decision tree...

> --- a/target/riscv/translate.c
> +++ b/target/riscv/translate.c
> @@ -569,6 +569,16 @@ static void gen_jal(DisasContext *ctx, int rd, target_ulong imm)
>          }
>      }
>  
> +#ifndef CONFIG_USER_ONLY
> +    if (ctx->cfg_ptr->ext_smctr || ctx->cfg_ptr->ext_ssctr) {
> +        TCGv dest = tcg_constant_tl(ctx->base.pc_next + imm);
> +        TCGv src = tcg_constant_tl(ctx->base.pc_next);
> +        TCGv tcg_rd = tcg_constant_tl((target_ulong)rd);
> +
> +        gen_helper_ctr_jal(tcg_env, src, dest, tcg_rd);
> +    }
> +#endif

... here.  All you need is to expose helper_ctr_add_entry().

With that,

> +void helper_ctr_popret(CPURISCVState *env, target_ulong src, target_ulong dest)
> +{
> +    riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_RETURN,
> +                            env->priv, env->virt_enabled);
> +}
> +
> +void helper_ctr_branch(CPURISCVState *env, target_ulong src, target_ulong dest,
> +                       target_ulong branch_taken)
> +{
> +    target_ulong curr_priv = env->priv;
> +    bool curr_virt = env->virt_enabled;
> +
> +    if (branch_taken) {
> +        riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_TAKEN_BRANCH,
> +                            curr_priv, curr_virt);
> +    } else {
> +        riscv_ctr_add_entry(env, src, dest, CTRDATA_TYPE_NONTAKEN_BRANCH,
> +                            curr_priv, curr_virt);
> +    }
> +}

these can go away, simply passing the correct CTRDATA_* constant at the right place.


r~