dlan17/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

vdso/helpers: Prepare introduction of struct vdso_clock

Browse Source 
To support multiple PTP clocks, the VDSO data structure needs to be
reworked. All clock specific data will end up in struct vdso_clock and in
struct vdso_time_data there will be an array of VDSO clocks. For now,
vdso_clock is simply a define which maps vdso_clock to vdso_time_data.

Prepare all functions which need the pointer to the vdso_clock array to
work well after the structures get reworked. Replace the struct vdso_time_data
pointer with a struct vdso_clock pointer where applicable.

No functional change.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250303-vdso-clock-v1-5-c1b5c69a166f@linutronix.de
This commit is contained in:
Anna-Maria Behnsen
2025-03-08 14:37:40 +01:00
committed by Thomas Gleixner
parent a05f14de04
commit e15bf9e34b
1 changed files with 12 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/vdso/helpers.h
+12 -8
View File
@@ -7,49 +7,53 @@
#include <asm/barrier.h>
#include <vdso/datapage.h>
static __always_inline u32 vdso_read_begin(const struct vdso_time_data *vd)
static __always_inline u32 vdso_read_begin(const struct vdso_clock *vc)
{
u32 seq;
while (unlikely((seq = READ_ONCE(vd->seq)) & 1))
while (unlikely((seq = READ_ONCE(vc->seq)) & 1))
cpu_relax();
smp_rmb();
return seq;
}
static __always_inline u32 vdso_read_retry(const struct vdso_time_data *vd,
static __always_inline u32 vdso_read_retry(const struct vdso_clock *vc,
u32 start)
{
u32 seq;
smp_rmb();
seq = READ_ONCE(vd->seq);
seq = READ_ONCE(vc->seq);
return seq != start;
}
static __always_inline void vdso_write_begin(struct vdso_time_data *vd)
{
struct vdso_clock *vc = vd;
/*
* WRITE_ONCE() is required otherwise the compiler can validly tear
* updates to vd[x].seq and it is possible that the value seen by the
* reader 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);
WRITE_ONCE(vc[CS_HRES_COARSE].seq, vc[CS_HRES_COARSE].seq + 1);
WRITE_ONCE(vc[CS_RAW].seq, vc[CS_RAW].seq + 1);
smp_wmb();
}
static __always_inline void vdso_write_end(struct vdso_time_data *vd)
{
struct vdso_clock *vc = vd;
smp_wmb();
/*
* WRITE_ONCE() is required otherwise the compiler can validly tear
* updates to vd[x].seq and it is possible that the value seen by the
* reader 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);
WRITE_ONCE(vc[CS_HRES_COARSE].seq, vc[CS_HRES_COARSE].seq + 1);
WRITE_ONCE(vc[CS_RAW].seq, vc[CS_RAW].seq + 1);
}
#endif /* !__ASSEMBLY__ */