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[PATCH RFC 4/8] target/riscv: Support generic CSR indirect access
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From: |
Atish Patra |
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Subject: |
[PATCH RFC 4/8] target/riscv: Support generic CSR indirect access |
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Date: |
Fri, 16 Feb 2024 16:01:30 -0800 |
From: Kaiwen Xue <kaiwenx@rivosinc.com>
This adds the indirect access registers required by sscsrind/smcsrind
and the operations on them. Note that xiselect and xireg are used for
both AIA and sxcsrind, and the behavior of accessing them depends on
whether each extension is enabled and the value stored in xiselect.
Co-developed-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Kaiwen Xue <kaiwenx@rivosinc.com>
---
target/riscv/cpu_bits.h | 28 +++++++-
target/riscv/csr.c | 146 +++++++++++++++++++++++++++++++++++++++-
2 files changed, 169 insertions(+), 5 deletions(-)
diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index 0ee91e502e8f..3a66f83009b5 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -176,6 +176,13 @@
#define CSR_MISELECT 0x350
#define CSR_MIREG 0x351
+/* Machine Indirect Register Alias */
+#define CSR_MIREG2 0x352
+#define CSR_MIREG3 0x353
+#define CSR_MIREG4 0x355
+#define CSR_MIREG5 0x356
+#define CSR_MIREG6 0x357
+
/* Machine-Level Interrupts (AIA) */
#define CSR_MTOPEI 0x35c
#define CSR_MTOPI 0xfb0
@@ -225,6 +232,13 @@
#define CSR_SISELECT 0x150
#define CSR_SIREG 0x151
+/* Supervisor Indirect Register Alias */
+#define CSR_SIREG2 0x152
+#define CSR_SIREG3 0x153
+#define CSR_SIREG4 0x155
+#define CSR_SIREG5 0x156
+#define CSR_SIREG6 0x157
+
/* Supervisor-Level Interrupts (AIA) */
#define CSR_STOPEI 0x15c
#define CSR_STOPI 0xdb0
@@ -291,6 +305,13 @@
#define CSR_VSISELECT 0x250
#define CSR_VSIREG 0x251
+/* Virtual Supervisor Indirect Alias */
+#define CSR_VSIREG2 0x252
+#define CSR_VSIREG3 0x253
+#define CSR_VSIREG4 0x255
+#define CSR_VSIREG5 0x256
+#define CSR_VSIREG6 0x257
+
/* VS-Level Interrupts (H-extension with AIA) */
#define CSR_VSTOPEI 0x25c
#define CSR_VSTOPI 0xeb0
@@ -847,10 +868,13 @@ typedef enum RISCVException {
#define ISELECT_IMSIC_EIE63 0xff
#define ISELECT_IMSIC_FIRST ISELECT_IMSIC_EIDELIVERY
#define ISELECT_IMSIC_LAST ISELECT_IMSIC_EIE63
-#define ISELECT_MASK 0x1ff
+#define ISELECT_MASK_AIA 0x1ff
+
+/* MISELECT, SISELECT, and VSISELECT bits (AIA) */
+#define ISELECT_MASK_SXCSRIND 0xfff
/* Dummy [M|S|VS]ISELECT value for emulating [M|S|VS]TOPEI CSRs */
-#define ISELECT_IMSIC_TOPEI (ISELECT_MASK + 1)
+#define ISELECT_IMSIC_TOPEI (ISELECT_MASK_AIA + 1)
/* IMSIC bits (AIA) */
#define IMSIC_TOPEI_IID_SHIFT 16
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 89a1325a02a5..a1c10f1d010a 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -287,6 +287,17 @@ static int aia_any32(CPURISCVState *env, int csrno)
return any32(env, csrno);
}
+static RISCVException sxcsrind_any(CPURISCVState *env, int csrno)
+{
+ RISCVCPU *cpu = env_archcpu(env);
+
+ if (!cpu->cfg.ext_smcsrind) {
+ return RISCV_EXCP_ILLEGAL_INST;
+ }
+
+ return RISCV_EXCP_NONE;
+}
+
static int sxcsrind_or_aia_any(CPURISCVState *env, int csrno)
{
if (!riscv_cpu_cfg(env)->ext_smaia && !riscv_cpu_cfg(env)->ext_smcsrind) {
@@ -355,6 +366,17 @@ static int aia_smode32(CPURISCVState *env, int csrno)
return smode32(env, csrno);
}
+static RISCVException sxcsrind_smode(CPURISCVState *env, int csrno)
+{
+ RISCVCPU *cpu = env_archcpu(env);
+
+ if (!cpu->cfg.ext_sscsrind) {
+ return RISCV_EXCP_ILLEGAL_INST;
+ }
+
+ return smode(env, csrno);
+}
+
static int sxcsrind_or_aia_smode(CPURISCVState *env, int csrno)
{
if (!riscv_cpu_cfg(env)->ext_ssaia && !riscv_cpu_cfg(env)->ext_sscsrind) {
@@ -383,6 +405,17 @@ static RISCVException hmode32(CPURISCVState *env, int
csrno)
}
+static RISCVException sxcsrind_hmode(CPURISCVState *env, int csrno)
+{
+ RISCVCPU *cpu = env_archcpu(env);
+
+ if (!cpu->cfg.ext_sscsrind) {
+ return RISCV_EXCP_ILLEGAL_INST;
+ }
+
+ return hmode(env, csrno);
+}
+
static int sxcsrind_or_aia_hmode(CPURISCVState *env, int csrno)
{
if (!riscv_cpu_cfg(env)->ext_ssaia && !riscv_cpu_cfg(env)->ext_sscsrind) {
@@ -1926,7 +1959,12 @@ static int rmw_xiselect(CPURISCVState *env, int csrno,
target_ulong *val,
*val = *iselect;
}
- wr_mask &= ISELECT_MASK;
+ if (riscv_cpu_cfg(env)->ext_smcsrind || riscv_cpu_cfg(env)->ext_sscsrind) {
+ wr_mask &= ISELECT_MASK_SXCSRIND;
+ } else {
+ wr_mask &= ISELECT_MASK_AIA;
+ }
+
if (wr_mask) {
*iselect = (*iselect & ~wr_mask) | (new_val & wr_mask);
}
@@ -2065,6 +2103,59 @@ done:
return RISCV_EXCP_NONE;
}
+/*
+ * rmw_xireg_sxcsrind: Perform indirect access to xireg and xireg2-xireg6
+ *
+ * Perform indirect access to xireg and xireg2-xireg6.
+ * This is a generic interface for all xireg CSRs. Apart from AIA, all other
+ * extension using sxcsrind should be implemented here.
+ */
+static int rmw_xireg_sxcsrind(CPURISCVState *env, int csrno,
+ target_ulong isel, target_ulong *val,
+ target_ulong new_val, target_ulong wr_mask)
+{
+ return -EINVAL;
+}
+
+static int rmw_xiregi(CPURISCVState *env, int csrno, target_ulong *val,
+ target_ulong new_val, target_ulong wr_mask)
+{
+ bool virt = false;
+ int ret = -EINVAL;
+ target_ulong isel;
+
+ ret = smstateen_acc_ok(env, 0, SMSTATEEN0_SVSLCT);
+ if (ret != RISCV_EXCP_NONE) {
+ return ret;
+ }
+
+ /* Translate CSR number for VS-mode */
+ csrno = sxcsrind_xlate_vs_csrno(env, csrno);
+
+ if (CSR_MIREG <= csrno && csrno <= CSR_MIREG6 &&
+ csrno != CSR_MIREG4 - 1) {
+ isel = env->miselect;
+ } else if (CSR_SIREG <= csrno && csrno <= CSR_SIREG6 &&
+ csrno != CSR_SIREG4 - 1) {
+ isel = env->siselect;
+ } else if (CSR_VSIREG <= csrno && csrno <= CSR_VSIREG6 &&
+ csrno != CSR_VSIREG4 - 1) {
+ isel = env->vsiselect;
+ virt = true;
+ } else {
+ goto done;
+ }
+
+ return rmw_xireg_sxcsrind(env, csrno, isel, val, new_val, wr_mask);
+
+done:
+ if (ret) {
+ return (env->virt_enabled && virt) ?
+ RISCV_EXCP_VIRT_INSTRUCTION_FAULT : RISCV_EXCP_ILLEGAL_INST;
+ }
+ return RISCV_EXCP_NONE;
+}
+
static int rmw_xireg(CPURISCVState *env, int csrno, target_ulong *val,
target_ulong new_val, target_ulong wr_mask)
{
@@ -2096,8 +2187,21 @@ static int rmw_xireg(CPURISCVState *env, int csrno,
target_ulong *val,
goto done;
};
+ /*
+ * Use the xiselect range to determine actual op on xireg.
+ *
+ * Since we only checked the existence of AIA or Indirect Access in the
+ * predicate, we should check the existence of the exact extension when
+ * we get to a specific range and return illegal instruction exception even
+ * in VS-mode.
+ */
if (xiselect_aia_range(isel)) {
return rmw_xireg_aia(env, csrno, isel, val, new_val, wr_mask);
+ } else if (riscv_cpu_cfg(env)->ext_smcsrind ||
+ riscv_cpu_cfg(env)->ext_sscsrind) {
+ return rmw_xireg_sxcsrind(env, csrno, isel, val, new_val, wr_mask);
+ } else {
+ return RISCV_EXCP_ILLEGAL_INST;
}
done:
@@ -2480,7 +2584,7 @@ static RISCVException write_mstateen0(CPURISCVState *env,
int csrno,
* TODO: Do we need to check ssaia as well ? Can we enable ssaia without
* smaia ?
*/
- if (riscv_cpu_cfg(env)->ext_smaia) {
+ if (riscv_cpu_cfg(env)->ext_smaia || riscv_cpu_cfg(env)->ext_smcsrind) {
wr_mask |= SMSTATEEN0_SVSLCT;
}
@@ -2569,7 +2673,7 @@ static RISCVException write_hstateen0(CPURISCVState *env,
int csrno,
wr_mask |= SMSTATEEN0_FCSR;
}
- if (riscv_cpu_cfg(env)->ext_ssaia) {
+ if (riscv_cpu_cfg(env)->ext_ssaia || riscv_cpu_cfg(env)->ext_sscsrind) {
wr_mask |= SMSTATEEN0_SVSLCT;
}
@@ -4866,6 +4970,18 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
[CSR_MIREG] = { "mireg", sxcsrind_or_aia_any, NULL, NULL,
rmw_xireg },
+ /* Machine Indirect Register Alias */
+ [CSR_MIREG2] = { "mireg2", sxcsrind_any, NULL, NULL, rmw_xiregi,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
+ [CSR_MIREG3] = { "mireg3", sxcsrind_any, NULL, NULL, rmw_xiregi,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
+ [CSR_MIREG4] = { "mireg4", sxcsrind_any, NULL, NULL, rmw_xiregi,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
+ [CSR_MIREG5] = { "mireg5", sxcsrind_any, NULL, NULL, rmw_xiregi,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
+ [CSR_MIREG6] = { "mireg6", sxcsrind_any, NULL, NULL, rmw_xiregi,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
+
/* Machine-Level Interrupts (AIA) */
[CSR_MTOPEI] = { "mtopei", aia_any, NULL, NULL, rmw_xtopei },
[CSR_MTOPI] = { "mtopi", aia_any, read_mtopi },
@@ -4987,6 +5103,18 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
[CSR_SIREG] = { "sireg", sxcsrind_or_aia_smode, NULL, NULL,
rmw_xireg },
+ /* Supervisor Indirect Register Alias */
+ [CSR_SIREG2] = { "sireg2", sxcsrind_smode, NULL, NULL, rmw_xiregi,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
+ [CSR_SIREG3] = { "sireg3", sxcsrind_smode, NULL, NULL, rmw_xiregi,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
+ [CSR_SIREG4] = { "sireg4", sxcsrind_smode, NULL, NULL, rmw_xiregi,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
+ [CSR_SIREG5] = { "sireg5", sxcsrind_smode, NULL, NULL, rmw_xiregi,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
+ [CSR_SIREG6] = { "sireg6", sxcsrind_smode, NULL, NULL, rmw_xiregi,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
+
/* Supervisor-Level Interrupts (AIA) */
[CSR_STOPEI] = { "stopei", aia_smode, NULL, NULL, rmw_xtopei },
[CSR_STOPI] = { "stopi", aia_smode, read_stopi },
@@ -5069,6 +5197,18 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
[CSR_VSIREG] = { "vsireg", sxcsrind_or_aia_hmode, NULL, NULL,
rmw_xireg },
+ /* Virtual Supervisor Indirect Alias */
+ [CSR_VSIREG2] = { "vsireg2", sxcsrind_hmode, NULL, NULL, rmw_xiregi,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
+ [CSR_VSIREG3] = { "vsireg3", sxcsrind_hmode, NULL, NULL, rmw_xiregi,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
+ [CSR_VSIREG4] = { "vsireg4", sxcsrind_hmode, NULL, NULL, rmw_xiregi,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
+ [CSR_VSIREG5] = { "vsireg5", sxcsrind_hmode, NULL, NULL, rmw_xiregi,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
+ [CSR_VSIREG6] = { "vsireg6", sxcsrind_hmode, NULL, NULL, rmw_xiregi,
+ .min_priv_ver = PRIV_VERSION_1_12_0 },
+
/* VS-Level Interrupts (H-extension with AIA) */
[CSR_VSTOPEI] = { "vstopei", aia_hmode, NULL, NULL, rmw_xtopei },
[CSR_VSTOPI] = { "vstopi", aia_hmode, read_vstopi },
--
2.34.1
- [PATCH RFC 0/8] Add Counter delegation ISA extension support, Atish Patra, 2024/02/16
- [PATCH RFC 1/8] target/riscv: Add properties for Indirect CSR Access extension, Atish Patra, 2024/02/16
- [PATCH RFC 2/8] target/riscv: Decouple AIA processing from xiselect and xireg, Atish Patra, 2024/02/16
- [PATCH RFC 3/8] target/riscv: Enable S*stateen bits for AIA, Atish Patra, 2024/02/16
- [PATCH RFC 5/8] target/riscv: Add smcdeleg/ssccfg properties, Atish Patra, 2024/02/16
- [PATCH RFC 6/8] target/riscv: Add counter delegation definitions, Atish Patra, 2024/02/16
- [PATCH RFC 7/8] target/riscv: Add select value range check for counter delegation, Atish Patra, 2024/02/16
- [PATCH RFC 4/8] target/riscv: Support generic CSR indirect access,
Atish Patra <=
- [PATCH RFC 8/8] target/riscv: Add counter delegation/configuration support, Atish Patra, 2024/02/16
- Re: [PATCH RFC 0/8] Add Counter delegation ISA extension support, Daniel Henrique Barboza, 2024/02/21