zicfilp introduces a new state elp ("expected landing pad") in cpu.
During normal execution, elp is idle (NO_LP_EXPECTED) i.e not expecting
landing pad. On an indirect call, elp moves LP_EXPECTED. When elp is
LP_EXPECTED, only a subsquent landing pad instruction can set state back
to NO_LP_EXPECTED. On reset, elp is set to NO_LP_EXPECTED.
zicfilp is enabled via bit2 in *envcfg CSRs. Enabling control for M-mode
is in mseccfg CSR at bit position 10.
On trap, elp state is saved away in *status.
Adds elp to the migration state as well.
Signed-off-by: Deepak Gupta <de...@rivosinc.com>
Co-developed-by: Jim Shu <jim....@sifive.com>
Co-developed-by: Andy Chiu <andy.c...@sifive.com>
Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
Reviewed-by: Alistair Francis <alistair.fran...@wdc.com>
---
target/riscv/cpu.c | 3 +++
target/riscv/cpu.h | 2 ++
target/riscv/cpu_bits.h | 6 ++++++
target/riscv/csr.c | 31 +++++++++++++++++++++++++++++++
target/riscv/machine.c | 19 +++++++++++++++++++
target/riscv/pmp.c | 5 +++++
target/riscv/pmp.h | 3 ++-
7 files changed, 68 insertions(+), 1 deletion(-)
diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 43156ebb92..2d031e3e74 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -994,6 +994,9 @@ static void riscv_cpu_reset_hold(Object *obj, ResetType
type)
/* mmte is supposed to have pm.current hardwired to 1 */
env->mmte |= (EXT_STATUS_INITIAL | MMTE_M_PM_CURRENT);
+ /* on reset elp is clear */
+ env->elp = false;
+
/*
* Bits 10, 6, 2 and 12 of mideleg are read only 1 when the Hypervisor
* extension is enabled.
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 270a2a031c..b2dc419ad0 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -222,6 +222,8 @@ struct CPUArchState {
target_ulong jvt;
+ /* elp state for zicfilp extension */
+ bool elp;
#ifdef CONFIG_USER_ONLY
uint32_t elf_flags;
#endif
diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index c257c5ed7d..b05ebe6f29 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -545,6 +545,8 @@
#define MSTATUS_TVM 0x00100000 /* since: priv-1.10 */
#define MSTATUS_TW 0x00200000 /* since: priv-1.10 */
#define MSTATUS_TSR 0x00400000 /* since: priv-1.10 */
+#define MSTATUS_SPELP 0x00800000 /* zicfilp */
+#define MSTATUS_MPELP 0x020000000000 /* zicfilp */
#define MSTATUS_GVA 0x4000000000ULL
#define MSTATUS_MPV 0x8000000000ULL
@@ -575,6 +577,7 @@ typedef enum {
#define SSTATUS_XS 0x00018000
#define SSTATUS_SUM 0x00040000 /* since: priv-1.10 */
#define SSTATUS_MXR 0x00080000
+#define SSTATUS_SPELP MSTATUS_SPELP /* zicfilp */
#define SSTATUS64_UXL 0x0000000300000000ULL
@@ -747,6 +750,7 @@ typedef enum RISCVException {
/* Execution environment configuration bits */
#define MENVCFG_FIOM BIT(0)
+#define MENVCFG_LPE BIT(2) /* zicfilp */
#define MENVCFG_CBIE (3UL << 4)
#define MENVCFG_CBCFE BIT(6)
#define MENVCFG_CBZE BIT(7)
@@ -760,11 +764,13 @@ typedef enum RISCVException {
#define MENVCFGH_STCE BIT(31)
#define SENVCFG_FIOM MENVCFG_FIOM
+#define SENVCFG_LPE MENVCFG_LPE
#define SENVCFG_CBIE MENVCFG_CBIE
#define SENVCFG_CBCFE MENVCFG_CBCFE
#define SENVCFG_CBZE MENVCFG_CBZE
#define HENVCFG_FIOM MENVCFG_FIOM
+#define HENVCFG_LPE MENVCFG_LPE
#define HENVCFG_CBIE MENVCFG_CBIE
#define HENVCFG_CBCFE MENVCFG_CBCFE
#define HENVCFG_CBZE MENVCFG_CBZE
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 432c59dc66..5771a14848 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -1400,6 +1400,11 @@ static RISCVException write_mstatus(CPURISCVState *env,
int csrno,
}
}
+ /* If cfi lp extension is available, then apply cfi lp mask */
+ if (env_archcpu(env)->cfg.ext_zicfilp) {
+ mask |= (MSTATUS_MPELP | MSTATUS_SPELP);
+ }
+
mstatus = (mstatus & ~mask) | (val & mask);
env->mstatus = mstatus;
@@ -2101,6 +2106,10 @@ static RISCVException write_menvcfg(CPURISCVState *env,
int csrno,
mask |= (cfg->ext_svpbmt ? MENVCFG_PBMTE : 0) |
(cfg->ext_sstc ? MENVCFG_STCE : 0) |
(cfg->ext_svadu ? MENVCFG_ADUE : 0);
+
+ if (env_archcpu(env)->cfg.ext_zicfilp) {
+ mask |= MENVCFG_LPE;
+ }
}
env->menvcfg = (env->menvcfg & ~mask) | (val & mask);
@@ -2153,6 +2162,10 @@ static RISCVException write_senvcfg(CPURISCVState *env,
int csrno,
return ret;
}
+ if (env_archcpu(env)->cfg.ext_zicfilp) {
+ mask |= SENVCFG_LPE;
+ }
+
env->senvcfg = (env->senvcfg & ~mask) | (val & mask);
return RISCV_EXCP_NONE;
}
@@ -2190,6 +2203,10 @@ static RISCVException write_henvcfg(CPURISCVState *env,
int csrno,
if (riscv_cpu_mxl(env) == MXL_RV64) {
mask |= env->menvcfg & (HENVCFG_PBMTE | HENVCFG_STCE | HENVCFG_ADUE);
+
+ if (env_archcpu(env)->cfg.ext_zicfilp) {
+ mask |= HENVCFG_LPE;
+ }
}
env->henvcfg = (env->henvcfg & ~mask) | (val & mask);
@@ -2654,6 +2671,10 @@ static RISCVException read_sstatus_i128(CPURISCVState
*env, int csrno,
mask |= SSTATUS64_UXL;
}
+ if (env_archcpu(env)->cfg.ext_zicfilp) {
+ mask |= SSTATUS_SPELP;
+ }
+
*val = int128_make128(sstatus, add_status_sd(MXL_RV128, sstatus));
return RISCV_EXCP_NONE;
}
@@ -2665,6 +2686,11 @@ static RISCVException read_sstatus(CPURISCVState *env,
int csrno,
if (env->xl != MXL_RV32 || env->debugger) {
mask |= SSTATUS64_UXL;
}
+
+ if (env_archcpu(env)->cfg.ext_zicfilp) {
+ mask |= SSTATUS_SPELP;
+ }
+
/* TODO: Use SXL not MXL. */
*val = add_status_sd(riscv_cpu_mxl(env), env->mstatus & mask);
return RISCV_EXCP_NONE;
@@ -2680,6 +2706,11 @@ static RISCVException write_sstatus(CPURISCVState *env,
int csrno,
mask |= SSTATUS64_UXL;
}
}
+
+ if (env_archcpu(env)->cfg.ext_zicfilp) {
+ mask |= SSTATUS_SPELP;
+ }
+
target_ulong newval = (env->mstatus & ~mask) | (val & mask);
return write_mstatus(env, CSR_MSTATUS, newval);
}
diff --git a/target/riscv/machine.c b/target/riscv/machine.c
index 76f2150f78..873957c4ab 100644
--- a/target/riscv/machine.c
+++ b/target/riscv/machine.c
@@ -351,6 +351,24 @@ static const VMStateDescription vmstate_jvt = {
}
};
+static bool elp_needed(void *opaque)
+{
+ RISCVCPU *cpu = opaque;
+
+ return cpu->cfg.ext_zicfilp;
+}
+
+static const VMStateDescription vmstate_elp = {
+ .name = "cpu/elp",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .needed = elp_needed,
+ .fields = (const VMStateField[]) {
+ VMSTATE_BOOL(env.elp, RISCVCPU),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
const VMStateDescription vmstate_riscv_cpu = {
.name = "cpu",
.version_id = 10,
@@ -423,6 +441,7 @@ const VMStateDescription vmstate_riscv_cpu = {
&vmstate_debug,
&vmstate_smstateen,
&vmstate_jvt,
+ &vmstate_elp,
NULL
}
};
diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
index 9eea397e72..1111d08d08 100644
--- a/target/riscv/pmp.c
+++ b/target/riscv/pmp.c
@@ -598,6 +598,11 @@ void mseccfg_csr_write(CPURISCVState *env, target_ulong
val)
val &= ~(MSECCFG_MMWP | MSECCFG_MML | MSECCFG_RLB);
}
+ /* M-mode forward cfi to be enabled if cfi extension is implemented */
+ if (env_archcpu(env)->cfg.ext_zicfilp) {
+ val |= (val & MSECCFG_MLPE);
+ }
+
env->mseccfg = val;
}
diff --git a/target/riscv/pmp.h b/target/riscv/pmp.h
index f5c10ce85c..e0530a17a3 100644
--- a/target/riscv/pmp.h
+++ b/target/riscv/pmp.h
@@ -44,7 +44,8 @@ typedef enum {
MSECCFG_MMWP = 1 << 1,
MSECCFG_RLB = 1 << 2,
MSECCFG_USEED = 1 << 8,
- MSECCFG_SSEED = 1 << 9
+ MSECCFG_SSEED = 1 << 9,
+ MSECCFG_MLPE = 1 << 10,
} mseccfg_field_t;
typedef struct {
--
2.44.0
