x86/tsc: Remove obsolete ART to TSC conversion functions

JIRA: https://issues.redhat.com/browse/RHEL-61639

commit 0f532a7
Author: Lakshmi Sowjanya D <lakshmi.sowjanya.d@intel.com>
Date:   Mon May 13 16:08:09 2024 +0530

    x86/tsc: Remove obsolete ART to TSC conversion functions

    convert_art_to_tsc() and convert_art_ns_to_tsc() interfaces are no
    longer required. The conversion is now handled by the core code.

    Signed-off-by: Lakshmi Sowjanya D <lakshmi.sowjanya.d@intel.com>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Link: https://lore.kernel.org/r/20240513103813.5666-9-lakshmi.sowjanya.d@intel.com

Signed-off-by: Ivan Vecera <ivecera@redhat.com>

Author: ivecera

arch/x86/include/asm/tsc.h

@@ -27,9 +27,6 @@ static inline cycles_t get_cycles(void)
 }
 #define get_cycles get_cycles
 
-extern struct system_counterval_t convert_art_to_tsc(u64 art);
-extern struct system_counterval_t convert_art_ns_to_tsc(u64 art_ns);
-
 extern void tsc_early_init(void);
 extern void tsc_init(void);
 extern void mark_tsc_unstable(char *reason);

arch/x86/kernel/tsc.c

@@ -1297,66 +1297,6 @@ int unsynchronized_tsc(void)
 	return 0;
 }
 
-/*
- * Convert ART to TSC given numerator/denominator found in detect_art()
- */
-struct system_counterval_t convert_art_to_tsc(u64 art)
-{
-	u64 tmp, res, rem;
-
-	rem = do_div(art, art_base_clk.denominator);
-
-	res = art * art_base_clk.numerator;
-	tmp = rem * art_base_clk.numerator;
-
-	do_div(tmp, art_base_clk.denominator);
-	res += tmp + art_base_clk.offset;
-
-	return (struct system_counterval_t) {
-		.cs_id	= have_art ? CSID_X86_TSC : CSID_GENERIC,
-		.cycles	= res,
-	};
-}
-EXPORT_SYMBOL(convert_art_to_tsc);
-
-/**
- * convert_art_ns_to_tsc() - Convert ART in nanoseconds to TSC.
- * @art_ns: ART (Always Running Timer) in unit of nanoseconds
- *
- * PTM requires all timestamps to be in units of nanoseconds. When user
- * software requests a cross-timestamp, this function converts system timestamp
- * to TSC.
- *
- * This is valid when CPU feature flag X86_FEATURE_TSC_KNOWN_FREQ is set
- * indicating the tsc_khz is derived from CPUID[15H]. Drivers should check
- * that this flag is set before conversion to TSC is attempted.
- *
- * Return:
- * struct system_counterval_t - system counter value with the ID of the
- *	corresponding clocksource:
- *	cycles:		System counter value
- *	cs_id:		The clocksource ID for validating comparability
- */
-
-struct system_counterval_t convert_art_ns_to_tsc(u64 art_ns)
-{
-	u64 tmp, res, rem;
-
-	rem = do_div(art_ns, USEC_PER_SEC);
-
-	res = art_ns * tsc_khz;
-	tmp = rem * tsc_khz;
-
-	do_div(tmp, USEC_PER_SEC);
-	res += tmp;
-
-	return (struct system_counterval_t) {
-		.cs_id	= have_art ? CSID_X86_TSC : CSID_GENERIC,
-		.cycles	= res,
-	};
-}
-EXPORT_SYMBOL(convert_art_ns_to_tsc);
-
 static void tsc_refine_calibration_work(struct work_struct *work);
 static DECLARE_DELAYED_WORK(tsc_irqwork, tsc_refine_calibration_work);
 /**