/* SPDX-License-Identifier: GPL-2.0 */#ifndef __VDSO_HELPERS_H#define __VDSO_HELPERS_H #ifndef __ASSEMBLY__ #include <vdso/datapage.h> static __always_inline u32 vdso_read_begin(const struct vdso_data *vd){	u32 seq; 	while (unlikely((seq = READ_ONCE(vd->seq)) & 1))		cpu_relax(); 	smp_rmb();	return seq;} static __always_inline u32 vdso_read_retry(const struct vdso_data *vd,					   u32 start){	u32 seq; 	smp_rmb();	seq = READ_ONCE(vd->seq);	return seq != start;} static __always_inline void vdso_write_begin(struct vdso_data *vd){	/*	 * WRITE_ONCE it is required otherwise the compiler can validly tear	 * updates to vd[x].seq and it is possible that the value seen by the	 * reader it is inconsistent.	 */	WRITE_ONCE(vd[CS_HRES_COARSE].seq, vd[CS_HRES_COARSE].seq + 1);	WRITE_ONCE(vd[CS_RAW].seq, vd[CS_RAW].seq + 1);	smp_wmb();} static __always_inline void vdso_write_end(struct vdso_data *vd){	smp_wmb();	/*	 * WRITE_ONCE it is required otherwise the compiler can validly tear	 * updates to vd[x].seq and it is possible that the value seen by the	 * reader it is inconsistent.	 */	WRITE_ONCE(vd[CS_HRES_COARSE].seq, vd[CS_HRES_COARSE].seq + 1);	WRITE_ONCE(vd[CS_RAW].seq, vd[CS_RAW].seq + 1);} #endif /* !__ASSEMBLY__ */ #endif /* __VDSO_HELPERS_H */