y2038: vdso: powerpc: avoid timespec references

As a preparation to stop using 'struct timespec' in the kernel,
change the powerpc vdso implementation:

- split up the vdso data definition to have equivalent members
   for seconds and nanoseconds instead of an xtime structure

- use timespec64 as an intermediate for the xtime update

- change the asm-offsets definition to be based the appropriate
  fixed-length types

This is only a temporary fix for changing the types, in order
to actually support a 64-bit safe vdso32 version of clock_gettime(),
the entire powerpc vdso should be replaced with the generic
lib/vdso/ implementation. If that happens first, this patch
becomes obsolete.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/powerpc/include/asm/vdso_datapage.h

@@ -81,7 +81,8 @@ struct vdso_data {
 	__u32 stamp_sec_fraction;		/* fractional seconds of stamp_xtime */
 	__s32 wtom_clock_nsec;			/* Wall to monotonic clock nsec */
 	__s64 wtom_clock_sec;			/* Wall to monotonic clock sec */
-	struct timespec stamp_xtime;		/* xtime as at tb_orig_stamp */
+	__s64 stamp_xtime_sec;			/* xtime secs as at tb_orig_stamp */
+	__s64 stamp_xtime_nsec;			/* xtime nsecs as at tb_orig_stamp */
    	__u32 syscall_map_64[SYSCALL_MAP_SIZE]; /* map of syscalls  */
    	__u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
 };
@@ -101,7 +102,8 @@ struct vdso_data {
 	__u32 tz_dsttime;		/* Type of dst correction	0x5C */
 	__s32 wtom_clock_sec;			/* Wall to monotonic clock */
 	__s32 wtom_clock_nsec;
-	struct timespec stamp_xtime;	/* xtime as at tb_orig_stamp */
+	__s32 stamp_xtime_sec;		/* xtime seconds as at tb_orig_stamp */
+	__s32 stamp_xtime_nsec;		/* xtime nsecs as at tb_orig_stamp */
 	__u32 stamp_sec_fraction;	/* fractional seconds of stamp_xtime */
    	__u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
 	__u32 dcache_block_size;	/* L1 d-cache block size     */

arch/powerpc/kernel/asm-offsets.c

@@ -385,7 +385,8 @@ int main(void)
 	OFFSET(CFG_SYSCALL_MAP32, vdso_data, syscall_map_32);
 	OFFSET(WTOM_CLOCK_SEC, vdso_data, wtom_clock_sec);
 	OFFSET(WTOM_CLOCK_NSEC, vdso_data, wtom_clock_nsec);
-	OFFSET(STAMP_XTIME, vdso_data, stamp_xtime);
+	OFFSET(STAMP_XTIME_SEC, vdso_data, stamp_xtime_sec);
+	OFFSET(STAMP_XTIME_NSEC, vdso_data, stamp_xtime_nsec);
 	OFFSET(STAMP_SEC_FRAC, vdso_data, stamp_sec_fraction);
 	OFFSET(CFG_ICACHE_BLOCKSZ, vdso_data, icache_block_size);
 	OFFSET(CFG_DCACHE_BLOCKSZ, vdso_data, dcache_block_size);
@@ -395,18 +396,13 @@ int main(void)
 	OFFSET(CFG_SYSCALL_MAP64, vdso_data, syscall_map_64);
 	OFFSET(TVAL64_TV_SEC, __kernel_old_timeval, tv_sec);
 	OFFSET(TVAL64_TV_USEC, __kernel_old_timeval, tv_usec);
+#endif
+	OFFSET(TSPC64_TV_SEC, __kernel_timespec, tv_sec);
+	OFFSET(TSPC64_TV_NSEC, __kernel_timespec, tv_nsec);
 	OFFSET(TVAL32_TV_SEC, old_timeval32, tv_sec);
 	OFFSET(TVAL32_TV_USEC, old_timeval32, tv_usec);
-	OFFSET(TSPC64_TV_SEC, timespec, tv_sec);
-	OFFSET(TSPC64_TV_NSEC, timespec, tv_nsec);
 	OFFSET(TSPC32_TV_SEC, old_timespec32, tv_sec);
 	OFFSET(TSPC32_TV_NSEC, old_timespec32, tv_nsec);
-#else
-	OFFSET(TVAL32_TV_SEC, __kernel_old_timeval, tv_sec);
-	OFFSET(TVAL32_TV_USEC, __kernel_old_timeval, tv_usec);
-	OFFSET(TSPC32_TV_SEC, timespec, tv_sec);
-	OFFSET(TSPC32_TV_NSEC, timespec, tv_nsec);
-#endif
 	/* timeval/timezone offsets for use by vdso */
 	OFFSET(TZONE_TZ_MINWEST, timezone, tz_minuteswest);
 	OFFSET(TZONE_TZ_DSTTIME, timezone, tz_dsttime);

arch/powerpc/kernel/time.c

@@ -885,7 +885,7 @@ static notrace u64 timebase_read(struct clocksource *cs)
 
 void update_vsyscall(struct timekeeper *tk)
 {
-	struct timespec xt;
+	struct timespec64 xt;
 	struct clocksource *clock = tk->tkr_mono.clock;
 	u32 mult = tk->tkr_mono.mult;
 	u32 shift = tk->tkr_mono.shift;
@@ -957,7 +957,8 @@ void update_vsyscall(struct timekeeper *tk)
 	vdso_data->tb_to_xs = new_tb_to_xs;
 	vdso_data->wtom_clock_sec = tk->wall_to_monotonic.tv_sec;
 	vdso_data->wtom_clock_nsec = tk->wall_to_monotonic.tv_nsec;
-	vdso_data->stamp_xtime = xt;
+	vdso_data->stamp_xtime_sec = xt.tv_sec;
+	vdso_data->stamp_xtime_nsec = xt.tv_nsec;
 	vdso_data->stamp_sec_fraction = frac_sec;
 	smp_wmb();
 	++(vdso_data->tb_update_count);

arch/powerpc/kernel/vdso32/gettimeofday.S

@@ -15,10 +15,8 @@
 /* Offset for the low 32-bit part of a field of long type */
 #ifdef CONFIG_PPC64
 #define LOPART	4
-#define TSPEC_TV_SEC	TSPC64_TV_SEC+LOPART
 #else
 #define LOPART	0
-#define TSPEC_TV_SEC	TSPC32_TV_SEC
 #endif
 
 	.text
@@ -192,7 +190,7 @@ V_FUNCTION_BEGIN(__kernel_time)
 	bl	__get_datapage@local
 	mr	r9, r3			/* datapage ptr in r9 */
 
-	lwz	r3,STAMP_XTIME+TSPEC_TV_SEC(r9)
+	lwz	r3,STAMP_XTIME_SEC+LOWPART(r9)
 
 	cmplwi	r11,0			/* check if t is NULL */
 	beq	2f
@@ -268,7 +266,7 @@ __do_get_tspec:
 	 * as a 32.32 fixed-point number in r3 and r4.
 	 * Load & add the xtime stamp.
 	 */
-	lwz	r5,STAMP_XTIME+TSPEC_TV_SEC(r9)
+	lwz	r5,STAMP_XTIME_SEC+LOWPART(r9)
 	lwz	r6,STAMP_SEC_FRAC(r9)
 	addc	r4,r4,r6
 	adde	r3,r3,r5

arch/powerpc/kernel/vdso64/gettimeofday.S

@@ -116,8 +116,8 @@ V_FUNCTION_BEGIN(__kernel_clock_gettime)
 	 * CLOCK_REALTIME_COARSE, below values are needed for MONOTONIC_COARSE
 	 * too
 	 */
-	ld      r4,STAMP_XTIME+TSPC64_TV_SEC(r3)
-	ld      r5,STAMP_XTIME+TSPC64_TV_NSEC(r3)
+	ld      r4,STAMP_XTIME_SEC(r3)
+	ld      r5,STAMP_XTIME_NSEC(r3)
 	bne     cr6,75f
 
 	/* CLOCK_MONOTONIC_COARSE */
@@ -220,7 +220,7 @@ V_FUNCTION_BEGIN(__kernel_time)
 	mr	r11,r3			/* r11 holds t */
 	bl	V_LOCAL_FUNC(__get_datapage)
 
-	ld	r4,STAMP_XTIME+TSPC64_TV_SEC(r3)
+	ld	r4,STAMP_XTIME_SEC(r3)
 
 	cmpldi	r11,0			/* check if t is NULL */
 	beq	2f
@@ -265,7 +265,7 @@ V_FUNCTION_BEGIN(__do_get_tspec)
 	mulhdu	r6,r6,r5		/* in units of 2^-32 seconds */
 
 	/* Add stamp since epoch */
-	ld	r4,STAMP_XTIME+TSPC64_TV_SEC(r3)
+	ld	r4,STAMP_XTIME_SEC(r3)
 	lwz	r5,STAMP_SEC_FRAC(r3)
 	or	r0,r4,r5
 	or	r0,r0,r6