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Andrea ParriandGreg Kroah-Hartman
a2977c0ca3
commitd6cfd1770fupstream. The membarrier system call requires a full memory barrier after storing to rq->curr, before going back to user-space. The barrier is only needed when switching between processes: the barrier is implied by mmdrop() when switching from kernel to userspace, and it's not needed when switching from userspace to kernel. Rely on the feature/mechanism ARCH_HAS_MEMBARRIER_CALLBACKS and on the primitive membarrier_arch_switch_mm(), already adopted by the PowerPC architecture, to insert the required barrier. Fixes:fab957c11e("RISC-V: Atomic and Locking Code") Signed-off-by: Andrea Parri <parri.andrea@gmail.com> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/r/20240131144936.29190-2-parri.andrea@gmail.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com> Signed-off-by: WangYuli <wangyuli@uniontech.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>