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@efficios.com>
Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/r/20240131144936.29190-4-parri.andrea@gmail.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Andrea Parri 2024-01-31 15:49:35 +01:00 committed by Palmer Dabbelt
parent a14d11a0f5
commit 4ff4c745a1
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3 changed files with 19 additions and 1 deletions

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@ -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 */

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@ -1970,6 +1970,9 @@ 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

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@ -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;