powerpc/vdso: Fix clock_gettime_fallback for vdso32

The second argument of __kernel_clock_gettime64 points to a struct
__kernel_timespec, with 64-bit time_t, so use the clock_gettime64
syscall in the fallback function for the 32-bit VDSO. Similarly,
clock_getres_fallback should use the clock_getres_time64 syscall,
though it isn't yet called from the 32-bit VDSO.

Fixes: d0e3fc6 ("powerpc/vdso: Provide __kernel_clock_gettime64() on vdso32")
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
[chleroy: Moved into a single #ifdef __powerpc64__ block]
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0c0ab0eb3cc80687c326f76ff0dd5762b8812ecc.1610452505.git.christophe.leroy@csgroup.eu

Author: andreas-schwab

arch/powerpc/include/asm/vdso/gettimeofday.h

@@ -103,6 +103,8 @@ int gettimeofday_fallback(struct __kernel_old_timeval *_tv, struct timezone *_tz
 	return do_syscall_2(__NR_gettimeofday, (unsigned long)_tv, (unsigned long)_tz);
 }
 
+#ifdef __powerpc64__
+
 static __always_inline
 int clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
 {
@@ -115,10 +117,22 @@ int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
 	return do_syscall_2(__NR_clock_getres, _clkid, (unsigned long)_ts);
 }
 
-#ifdef CONFIG_VDSO32
+#else
 
 #define BUILD_VDSO32		1
 
+static __always_inline
+int clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
+{
+	return do_syscall_2(__NR_clock_gettime64, _clkid, (unsigned long)_ts);
+}
+
+static __always_inline
+int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
+{
+	return do_syscall_2(__NR_clock_getres_time64, _clkid, (unsigned long)_ts);
+}
+
 static __always_inline
 int clock_gettime32_fallback(clockid_t _clkid, struct old_timespec32 *_ts)
 {