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Message-Id: <20231211094414.8078-3-parri.andrea@gmail.com>
Date: Mon, 11 Dec 2023 10:44:12 +0100
From: Andrea Parri <parri.andrea@...il.com>
To: mathieu.desnoyers@...icios.com, paulmck@...nel.org,
palmer@...belt.com, paul.walmsley@...ive.com, aou@...s.berkeley.edu
Cc: mmaas@...gle.com, hboehm@...gle.com, striker@...ibm.com,
charlie@...osinc.com, rehn@...osinc.com,
linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
Andrea Parri <parri.andrea@...il.com>
Subject: [PATCH v2 2/4] locking: Introduce prepare_sync_core_cmd()
Introduce an architecture function that architectures can use to set
up ("prepare") SYNC_CORE commands.
The function will be used by RISC-V to update its "deferred icache-
flush" data structures (icache_stale_mask).
Architectures defining prepare_sync_core_cmd() static inline need to
select ARCH_HAS_PREPARE_SYNC_CORE_CMD.
Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Signed-off-by: Andrea Parri <parri.andrea@...il.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
---
include/linux/sync_core.h | 16 +++++++++++++++-
init/Kconfig | 3 +++
kernel/sched/membarrier.c | 1 +
3 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/include/linux/sync_core.h b/include/linux/sync_core.h
index 013da4b8b3272..67bb9794b8758 100644
--- a/include/linux/sync_core.h
+++ b/include/linux/sync_core.h
@@ -17,5 +17,19 @@ static inline void sync_core_before_usermode(void)
}
#endif
-#endif /* _LINUX_SYNC_CORE_H */
+#ifdef CONFIG_ARCH_HAS_PREPARE_SYNC_CORE_CMD
+#include <asm/sync_core.h>
+#else
+/*
+ * This is a dummy prepare_sync_core_cmd() implementation that can be used on
+ * all architectures which provide unconditional core serializing instructions
+ * in switch_mm().
+ * If your architecture doesn't provide such core serializing instructions in
+ * switch_mm(), you may need to write your own functions.
+ */
+static inline void prepare_sync_core_cmd(struct mm_struct *mm)
+{
+}
+#endif
+#endif /* _LINUX_SYNC_CORE_H */
diff --git a/init/Kconfig b/init/Kconfig
index 9ffb103fc927b..87daf50838f02 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1972,6 +1972,9 @@ source "kernel/Kconfig.locks"
config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
bool
+config ARCH_HAS_PREPARE_SYNC_CORE_CMD
+ bool
+
config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
bool
diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c
index 2ad881d07752c..58f801e013988 100644
--- a/kernel/sched/membarrier.c
+++ b/kernel/sched/membarrier.c
@@ -320,6 +320,7 @@ static int membarrier_private_expedited(int flags, int cpu_id)
MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE_READY))
return -EPERM;
ipi_func = ipi_sync_core;
+ prepare_sync_core_cmd(mm);
} else if (flags == MEMBARRIER_FLAG_RSEQ) {
if (!IS_ENABLED(CONFIG_RSEQ))
return -EINVAL;
--
2.34.1
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