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[PATCH v4 5/8] target/riscv: Implementation of enhanced PMP (ePMP)
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From: |
Alistair Francis |
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Subject: |
[PATCH v4 5/8] target/riscv: Implementation of enhanced PMP (ePMP) |
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Date: |
Mon, 19 Apr 2021 16:17:11 +1000 |
From: Hou Weiying <weiying_hou@outlook.com>
This commit adds support for ePMP v0.9.1.
The ePMP spec can be found in:
https://docs.google.com/document/d/1Mh_aiHYxemL0umN3GTTw8vsbmzHZ_nxZXgjgOUzbvc8
Signed-off-by: Hongzheng-Li <Ethan.Lee.QNL@gmail.com>
Signed-off-by: Hou Weiying <weiying_hou@outlook.com>
Signed-off-by: Myriad-Dreamin <camiyoru@gmail.com>
Message-Id:
<SG2PR02MB263462CCDBCBBAD36983C2CD93450@SG2PR02MB2634.apcprd02.prod.outlook.com>
[ Changes by AF:
- Rebase on master
- Update to latest spec
- Use a switch case to handle ePMP MML permissions
- Fix a few bugs
]
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
target/riscv/pmp.c | 154 ++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 146 insertions(+), 8 deletions(-)
diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
index e35988eec2..e1f5776316 100644
--- a/target/riscv/pmp.c
+++ b/target/riscv/pmp.c
@@ -90,11 +90,42 @@ static inline uint8_t pmp_read_cfg(CPURISCVState *env,
uint32_t pmp_index)
static void pmp_write_cfg(CPURISCVState *env, uint32_t pmp_index, uint8_t val)
{
if (pmp_index < MAX_RISCV_PMPS) {
- if (!pmp_is_locked(env, pmp_index)) {
- env->pmp_state.pmp[pmp_index].cfg_reg = val;
- pmp_update_rule(env, pmp_index);
+ bool locked = true;
+
+ if (riscv_feature(env, RISCV_FEATURE_EPMP)) {
+ /* mseccfg.RLB is set */
+ if (MSECCFG_RLB_ISSET(env)) {
+ locked = false;
+ }
+
+ /* mseccfg.MML is not set */
+ if (!MSECCFG_MML_ISSET(env) && !pmp_is_locked(env, pmp_index)) {
+ locked = false;
+ }
+
+ /* mseccfg.MML is set */
+ if (MSECCFG_MML_ISSET(env)) {
+ /* not adding execute bit */
+ if ((val & PMP_LOCK) != 0 && (val & PMP_EXEC) != PMP_EXEC) {
+ locked = false;
+ }
+ /* shared region and not adding X bit */
+ if ((val & PMP_LOCK) != PMP_LOCK &&
+ (val & 0x7) != (PMP_WRITE | PMP_EXEC)) {
+ locked = false;
+ }
+ }
} else {
+ if (!pmp_is_locked(env, pmp_index)) {
+ locked = false;
+ }
+ }
+
+ if (locked) {
qemu_log_mask(LOG_GUEST_ERROR, "ignoring pmpcfg write - locked\n");
+ } else {
+ env->pmp_state.pmp[pmp_index].cfg_reg = val;
+ pmp_update_rule(env, pmp_index);
}
} else {
qemu_log_mask(LOG_GUEST_ERROR,
@@ -217,6 +248,32 @@ static bool pmp_hart_has_privs_default(CPURISCVState *env,
target_ulong addr,
{
bool ret;
+ if (riscv_feature(env, RISCV_FEATURE_EPMP)) {
+ if (MSECCFG_MMWP_ISSET(env)) {
+ /*
+ * The Machine Mode Whitelist Policy (mseccfg.MMWP) is set
+ * so we default to deny all, even for M-mode.
+ */
+ *allowed_privs = 0;
+ return false;
+ } else if (MSECCFG_MML_ISSET(env)) {
+ /*
+ * The Machine Mode Lockdown (mseccfg.MML) bit is set
+ * so we can only execute code in M-mode with an applicable
+ * rule. Other modes are disabled.
+ */
+ if (mode == PRV_M && !(privs & PMP_EXEC)) {
+ ret = true;
+ *allowed_privs = PMP_READ | PMP_WRITE;
+ } else {
+ ret = false;
+ *allowed_privs = 0;
+ }
+
+ return ret;
+ }
+ }
+
if ((!riscv_feature(env, RISCV_FEATURE_PMP)) || (mode == PRV_M)) {
/*
* Privileged spec v1.10 states if HW doesn't implement any PMP entry
@@ -294,13 +351,94 @@ bool pmp_hart_has_privs(CPURISCVState *env, target_ulong
addr,
pmp_get_a_field(env->pmp_state.pmp[i].cfg_reg);
/*
- * If the PMP entry is not off and the address is in range, do the priv
- * check
+ * Convert the PMP permissions to match the truth table in the
+ * ePMP spec.
*/
+ const uint8_t epmp_operation =
+ ((env->pmp_state.pmp[i].cfg_reg & PMP_LOCK) >> 4) |
+ ((env->pmp_state.pmp[i].cfg_reg & PMP_READ) << 2) |
+ (env->pmp_state.pmp[i].cfg_reg & PMP_WRITE) |
+ ((env->pmp_state.pmp[i].cfg_reg & PMP_EXEC) >> 2);
+
if (((s + e) == 2) && (PMP_AMATCH_OFF != a_field)) {
- *allowed_privs = PMP_READ | PMP_WRITE | PMP_EXEC;
- if ((mode != PRV_M) || pmp_is_locked(env, i)) {
- *allowed_privs &= env->pmp_state.pmp[i].cfg_reg;
+ /*
+ * If the PMP entry is not off and the address is in range,
+ * do the priv check
+ */
+ if (!MSECCFG_MML_ISSET(env)) {
+ /*
+ * If mseccfg.MML Bit is not set, do pmp priv check
+ * This will always apply to regular PMP.
+ */
+ *allowed_privs = PMP_READ | PMP_WRITE | PMP_EXEC;
+ if ((mode != PRV_M) || pmp_is_locked(env, i)) {
+ *allowed_privs &= env->pmp_state.pmp[i].cfg_reg;
+ }
+ } else {
+ /*
+ * If mseccfg.MML Bit set, do the enhanced pmp priv check
+ */
+ if (mode == PRV_M) {
+ switch (epmp_operation) {
+ case 0:
+ case 1:
+ case 4:
+ case 5:
+ case 6:
+ case 7:
+ case 8:
+ *allowed_privs = 0;
+ break;
+ case 2:
+ case 3:
+ case 14:
+ *allowed_privs = PMP_READ | PMP_WRITE;
+ break;
+ case 9:
+ case 10:
+ *allowed_privs = PMP_EXEC;
+ break;
+ case 11:
+ case 13:
+ *allowed_privs = PMP_READ | PMP_EXEC;
+ break;
+ case 12:
+ case 15:
+ *allowed_privs = PMP_READ;
+ break;
+ }
+ } else {
+ switch (epmp_operation) {
+ case 0:
+ case 8:
+ case 9:
+ case 12:
+ case 13:
+ case 14:
+ *allowed_privs = 0;
+ break;
+ case 1:
+ case 10:
+ case 11:
+ *allowed_privs = PMP_EXEC;
+ break;
+ case 2:
+ case 4:
+ case 15:
+ *allowed_privs = PMP_READ;
+ break;
+ case 3:
+ case 6:
+ *allowed_privs = PMP_READ | PMP_WRITE;
+ break;
+ case 5:
+ *allowed_privs = PMP_READ | PMP_EXEC;
+ break;
+ case 7:
+ *allowed_privs = PMP_READ | PMP_WRITE | PMP_EXEC;
+ break;
+ }
+ }
}
ret = ((privs & *allowed_privs) == privs);
--
2.31.1
- [PATCH v4 0/8] RISC-V: Add support for ePMP v0.9.1, Alistair Francis, 2021/04/19
- [PATCH v4 1/8] target/riscv: Fix the PMP is locked check when using TOR, Alistair Francis, 2021/04/19
- [PATCH v4 2/8] target/riscv: Define ePMP mseccfg, Alistair Francis, 2021/04/19
- [PATCH v4 3/8] target/riscv: Add the ePMP feature, Alistair Francis, 2021/04/19
- [PATCH v4 4/8] target/riscv: Add ePMP CSR access functions, Alistair Francis, 2021/04/19
- [PATCH v4 5/8] target/riscv: Implementation of enhanced PMP (ePMP),
Alistair Francis <=
- [PATCH v4 6/8] target/riscv: Add a config option for ePMP, Alistair Francis, 2021/04/19
- [PATCH v4 7/8] target/riscv/pmp: Remove outdated comment, Alistair Francis, 2021/04/19
- [PATCH v4 8/8] target/riscv: Add ePMP support for the Ibex CPU, Alistair Francis, 2021/04/19
- Re: [PATCH v4 0/8] RISC-V: Add support for ePMP v0.9.1, Alistair Francis, 2021/04/19