From: "Christoph Müllner" <christoph.muellner@vrull.eu>
To: qemu-riscv@nongnu.org, qemu-devel@nongnu.org,
Alistair Francis <alistair.francis@wdc.com>,
Bin Meng <bin.meng@windriver.com>,
Philipp Tomsich <philipp.tomsich@vrull.eu>,
Palmer Dabbelt <palmer@dabbelt.com>,
Richard Henderson <richard.henderson@linaro.org>,
Daniel Henrique Barboza <dbarboza@ventanamicro.com>,
Andrew Jones <ajones@ventanamicro.com>
Cc: "Christoph Müllner" <christoph.muellner@vrull.eu>,
"Laurent Vivier" <laurent@vivier.eu>,
"Weiwei Li" <liwei1518@gmail.com>,
"Liu Zhiwei" <zhiwei_liu@linux.alibaba.com>
Subject: [RFC PATCH v2 4/4] linux-user/riscv: Implement dynamic memory consistency model support
Date: Fri, 9 Feb 2024 07:41:17 +0100 [thread overview]
Message-ID: <20240209064117.2746701-5-christoph.muellner@vrull.eu> (raw)
In-Reply-To: <20240209064117.2746701-1-christoph.muellner@vrull.eu>
This patch implements the dynamic memory consistency model prctl calls
for RISC-V. The implementation introduces a single boolean variable to
keep the DTSO state.
Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>
---
linux-user/riscv/target_prctl.h | 76 ++++++++++++++++++++++++++++++++-
target/riscv/cpu.c | 5 +++
target/riscv/cpu.h | 1 +
3 files changed, 81 insertions(+), 1 deletion(-)
diff --git a/linux-user/riscv/target_prctl.h b/linux-user/riscv/target_prctl.h
index eb53b31ad5..e54321d872 100644
--- a/linux-user/riscv/target_prctl.h
+++ b/linux-user/riscv/target_prctl.h
@@ -1 +1,75 @@
-/* No special prctl support required. */
+/*
+ * RISC-V specific prctl functions for linux-user
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#ifndef RISCV_TARGET_PRCTL_H
+#define RISCV_TARGET_PRCTL_H
+
+static inline void riscv_dtso_set_enable(CPURISCVState *env, bool enable)
+{
+ env->dtso_ena = enable;
+}
+
+static inline bool riscv_dtso_is_enabled(CPURISCVState *env)
+{
+ return env->dtso_ena;
+}
+
+static abi_long do_prctl_set_memory_consistency_model(CPUArchState *cpu_env,
+ abi_long arg2)
+{
+ RISCVCPU *cpu = env_archcpu(cpu_env);
+ bool dtso_ena_old = riscv_dtso_is_enabled(cpu_env);
+ bool dtso_ena_new;
+ bool has_dtso = cpu->cfg.ext_ssdtso;
+
+ switch (arg2) {
+ case PR_MEMORY_CONSISTENCY_MODEL_RISCV_WMO:
+ dtso_ena_new = false;
+ break;
+ case PR_MEMORY_CONSISTENCY_MODEL_RISCV_TSO:
+ dtso_ena_new = true;
+ break;
+ default:
+ return -TARGET_EINVAL;
+ }
+
+ /* No change requested. */
+ if (dtso_ena_old == dtso_ena_new)
+ return 0;
+
+ /* Enabling TSO only works if DTSO is available. */
+ if (dtso_ena_new && !has_dtso)
+ return -TARGET_EINVAL;
+
+ /* Switchin TSO->WMO is not allowed. */
+ if (!dtso_ena_new)
+ return -TARGET_EINVAL;
+
+ riscv_dtso_set_enable(cpu_env, dtso_ena_new);
+
+ /*
+ * No need to reschedule other threads, because the emulation
+ * of DTSO is fine (from a memory model view) if they are out
+ * of sync until they will eventually reschedule.
+ */
+
+ return 0;
+}
+
+#define do_prctl_set_memory_consistency_model \
+ do_prctl_set_memory_consistency_model
+
+static abi_long do_prctl_get_memory_consistency_model(CPUArchState *cpu_env)
+{
+ if (riscv_dtso_is_enabled(cpu_env))
+ return PR_MEMORY_CONSISTENCY_MODEL_RISCV_TSO;
+
+ return PR_MEMORY_CONSISTENCY_MODEL_RISCV_WMO;
+}
+
+#define do_prctl_get_memory_consistency_model \
+ do_prctl_get_memory_consistency_model
+
+#endif /* RISCV_TARGET_PRCTL_H */
diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index ee90c09600..2e2aac73dc 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -922,6 +922,11 @@ static void riscv_cpu_reset_hold(Object *obj)
if (mcc->parent_phases.hold) {
mcc->parent_phases.hold(obj);
}
+#ifdef CONFIG_USER_ONLY
+ /* Default is true if Ztso is enabled, false otherwise. */
+ env->dtso_ena = cpu->cfg.ext_ztso;
+#endif
+
#ifndef CONFIG_USER_ONLY
env->misa_mxl = mcc->misa_mxl_max;
env->priv = PRV_M;
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index f52dce78ba..69420b2ae3 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -200,6 +200,7 @@ struct CPUArchState {
#ifdef CONFIG_USER_ONLY
uint32_t elf_flags;
+ bool dtso_ena; /* Dynamic TSO enable */
#endif
#ifndef CONFIG_USER_ONLY
--
2.43.0
prev parent reply other threads:[~2024-02-09 6:42 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-09 6:41 [RFC PATCH v2 0/4] RISC-V: Add dynamic TSO support Christoph Müllner
2024-02-09 6:41 ` [RFC PATCH v2 1/4] RISC-V: Add support for Ssdtso Christoph Müllner
2024-02-09 6:41 ` [RFC PATCH v2 2/4] linux-user/riscv: Add Ssdtso extension to hwprobe Christoph Müllner
2024-02-09 6:41 ` [RFC PATCH v2 3/4] linux-user/prctl: Add dynamic memory consistency model prctl API Christoph Müllner
2024-02-09 6:41 ` Christoph Müllner [this message]
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