mips: Add support for generic vDSO

The mips vDSO library requires some adaptations to take advantage of the
newly introduced generic vDSO library.

Introduce the following changes:
 - Modification of vdso.c to be compliant with the common vdso datapage
 - Use of lib/vdso for gettimeofday

Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
[paul.burton@mips.com: Prepend $(src) to config-n32-o32-env.c path.]
Signed-off-by: Paul Burton <paul.burton@mips.com>

1 files changed, 2 insertions, 76 deletions

diff --git a/arch/mips/include/asm/vdso.h b/arch/mips/include/asm/vdso.h
index a013fa4a3682..cc7b516129a8 100644
--- a/arch/mips/include/asm/vdso.h
+++ b/arch/mips/include/asm/vdso.h
@@ -8,6 +8,7 @@
 #define __ASM_VDSO_H
 
 #include <linux/mm_types.h>
+#include <vdso/datapage.h>
 
 #include <asm/barrier.h>
 
@@ -49,84 +50,9 @@ extern struct mips_vdso_image vdso_image_o32;
 extern struct mips_vdso_image vdso_image_n32;
 #endif
 
-/**
- * union mips_vdso_data - Data provided by the kernel for the VDSO.
- * @xtime_sec:		Current real time (seconds part).
- * @xtime_nsec:		Current real time (nanoseconds part, shifted).
- * @wall_to_mono_sec:	Wall-to-monotonic offset (seconds part).
- * @wall_to_mono_nsec:	Wall-to-monotonic offset (nanoseconds part).
- * @seq_count:		Counter to synchronise updates (odd = updating).
- * @cs_shift:		Clocksource shift value.
- * @clock_mode:		Clocksource to use for time functions.
- * @cs_mult:		Clocksource multiplier value.
- * @cs_cycle_last:	Clock cycle value at last update.
- * @cs_mask:		Clocksource mask value.
- * @tz_minuteswest:	Minutes west of Greenwich (from timezone).
- * @tz_dsttime:		Type of DST correction (from timezone).
- *
- * This structure contains data needed by functions within the VDSO. It is
- * populated by the kernel and mapped read-only into user memory. The time
- * fields are mirrors of internal data from the timekeeping infrastructure.
- *
- * Note: Care should be taken when modifying as the layout must remain the same
- * for both 64- and 32-bit (for 32-bit userland on 64-bit kernel).
- */
 union mips_vdso_data {
-	struct {
-		u64 xtime_sec;
-		u64 xtime_nsec;
-		u64 wall_to_mono_sec;
-		u64 wall_to_mono_nsec;
-		u32 seq_count;
-		u32 cs_shift;
-		u8 clock_mode;
-		u32 cs_mult;
-		u64 cs_cycle_last;
-		u64 cs_mask;
-		s32 tz_minuteswest;
-		s32 tz_dsttime;
-	};
-
+	struct vdso_data data[CS_BASES];
 	u8 page[PAGE_SIZE];
 };
 
-static inline u32 vdso_data_read_begin(const union mips_vdso_data *data)
-{
-	u32 seq;
-
-	while (true) {
-		seq = READ_ONCE(data->seq_count);
-		if (likely(!(seq & 1))) {
-			/* Paired with smp_wmb() in vdso_data_write_*(). */
-			smp_rmb();
-			return seq;
-		}
-
-		cpu_relax();
-	}
-}
-
-static inline bool vdso_data_read_retry(const union mips_vdso_data *data,
-					u32 start_seq)
-{
-	/* Paired with smp_wmb() in vdso_data_write_*(). */
-	smp_rmb();
-	return unlikely(data->seq_count != start_seq);
-}
-
-static inline void vdso_data_write_begin(union mips_vdso_data *data)
-{
-	++data->seq_count;
-
-	/* Ensure sequence update is written before other data page values. */
-	smp_wmb();
-}
-
-static inline void vdso_data_write_end(union mips_vdso_data *data)
-{
-	/* Ensure data values are written before updating sequence again. */
-	smp_wmb();
-	++data->seq_count;
-}
-
 #endif /* __ASM_VDSO_H */