powerpc: remove the last remnants of cputime_t

cputime_t was a core kernel type, removed by commits
ed5c8c85..b672592f. As explained in commit b672592f
("sched/cputime: Remove generic asm headers"), the final cleanup
is for the arch to provide cputime_to_nsec[s](). Commit ade7667a
("powerpc: Add cputime_to_nsecs()") did that, but justdidn't remove
the then-unused cputime_to_usecs(), cputime_t type, and associated
remnants.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221006105653.115829-1-npiggin@gmail.com

arch/powerpc/include/asm/cputime.h

@@ -21,23 +21,8 @@
 #include <asm/param.h>
 #include <asm/firmware.h>
 
-typedef u64 __nocast cputime_t;
-typedef u64 __nocast cputime64_t;
-
-#define cmpxchg_cputime(ptr, old, new) cmpxchg(ptr, old, new)
-
 #ifdef __KERNEL__
-/*
- * Convert cputime <-> microseconds
- */
-extern u64 __cputime_usec_factor;
-
-static inline unsigned long cputime_to_usecs(const cputime_t ct)
-{
-	return mulhdu((__force u64) ct, __cputime_usec_factor);
-}
-
-#define cputime_to_nsecs(cputime) tb_to_ns((__force u64)cputime)
+#define cputime_to_nsecs(cputime) tb_to_ns(cputime)
 
 /*
  * PPC64 uses PACA which is task independent for storing accounting data while

arch/powerpc/kernel/time.c

@@ -130,7 +130,7 @@ unsigned long tb_ticks_per_jiffy;
 unsigned long tb_ticks_per_usec = 100; /* sane default */
 EXPORT_SYMBOL(tb_ticks_per_usec);
 unsigned long tb_ticks_per_sec;
-EXPORT_SYMBOL(tb_ticks_per_sec);	/* for cputime_t conversions */
+EXPORT_SYMBOL(tb_ticks_per_sec);	/* for cputime conversions */
 
 DEFINE_SPINLOCK(rtc_lock);
 EXPORT_SYMBOL_GPL(rtc_lock);
@@ -150,21 +150,6 @@ EXPORT_SYMBOL_GPL(ppc_tb_freq);
 bool tb_invalid;
 
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
-/*
- * Factor for converting from cputime_t (timebase ticks) to
- * microseconds. This is stored as 0.64 fixed-point binary fraction.
- */
-u64 __cputime_usec_factor;
-EXPORT_SYMBOL(__cputime_usec_factor);
-
-static void calc_cputime_factors(void)
-{
-	struct div_result res;
-
-	div128_by_32(1000000, 0, tb_ticks_per_sec, &res);
-	__cputime_usec_factor = res.result_low;
-}
-
 /*
  * Read the SPURR on systems that have it, otherwise the PURR,
  * or if that doesn't exist return the timebase value passed in.
@@ -369,10 +354,7 @@ void vtime_flush(struct task_struct *tsk)
 	acct->hardirq_time = 0;
 	acct->softirq_time = 0;
 }
-
-#else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
-#define calc_cputime_factors()
-#endif
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
 
 void __delay(unsigned long loops)
 {
@@ -914,7 +896,6 @@ void __init time_init(void)
 	tb_ticks_per_jiffy = ppc_tb_freq / HZ;
 	tb_ticks_per_sec = ppc_tb_freq;
 	tb_ticks_per_usec = ppc_tb_freq / 1000000;
-	calc_cputime_factors();
 
 	/*
 	 * Compute scale factor for sched_clock.