mips: vdso: Use generic VDSO clock mode storage

Switch to the generic VDSO clock mode storage.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lkml.kernel.org/r/20200207124403.244684017@linutronix.de

arch/mips/Kconfig

@@ -4,7 +4,6 @@ config MIPS
 	default y
 	select ARCH_32BIT_OFF_T if !64BIT
 	select ARCH_BINFMT_ELF_STATE if MIPS_FP_SUPPORT
-	select ARCH_CLOCKSOURCE_DATA
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_PTE_SPECIAL if !(32BIT && CPU_HAS_RIXI)
@@ -38,6 +37,7 @@ config MIPS
 	select GENERIC_SCHED_CLOCK if !CAVIUM_OCTEON_SOC
 	select GENERIC_SMP_IDLE_THREAD
 	select GENERIC_TIME_VSYSCALL
+	select GENERIC_VDSO_CLOCK_MODE
 	select GUP_GET_PTE_LOW_HIGH if CPU_MIPS32 && PHYS_ADDR_T_64BIT
 	select HANDLE_DOMAIN_IRQ
 	select HAVE_ARCH_COMPILER_H

arch/mips/include/asm/clocksource.h

@@ -3,23 +3,11 @@
  * Copyright (C) 2015 Imagination Technologies
  * Author: Alex Smith <alex.smith@imgtec.com>
  */
-
 #ifndef __ASM_CLOCKSOURCE_H
 #define __ASM_CLOCKSOURCE_H
 
-#include <linux/types.h>
-
-/* VDSO clocksources. */
-#define VDSO_CLOCK_NONE		0	/* No suitable clocksource. */
-#define VDSO_CLOCK_R4K		1	/* Use the coprocessor 0 count. */
-#define VDSO_CLOCK_GIC		2	/* Use the GIC. */
-
-/**
- * struct arch_clocksource_data - Architecture-specific clocksource information.
- * @vdso_clock_mode: Method the VDSO should use to access the clocksource.
- */
-struct arch_clocksource_data {
-	u8 vdso_clock_mode;
-};
+#define VDSO_ARCH_CLOCKMODES	\
+	VDSO_CLOCKMODE_R4K,	\
+	VDSO_CLOCKMODE_GIC
 
 #endif /* __ASM_CLOCKSOURCE_H */

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

@@ -24,8 +24,6 @@
 
 #define VDSO_HAS_CLOCK_GETRES		1
 
-#define __VDSO_USE_SYSCALL		ULLONG_MAX
-
 static __always_inline long gettimeofday_fallback(
 				struct __kernel_old_timeval *_tv,
 				struct timezone *_tz)
@@ -175,28 +173,20 @@ static __always_inline u64 read_gic_count(const struct vdso_data *data)
 
 static __always_inline u64 __arch_get_hw_counter(s32 clock_mode)
 {
-#ifdef CONFIG_CLKSRC_MIPS_GIC
-	const struct vdso_data *data = get_vdso_data();
-#endif
-	u64 cycle_now;
-
-	switch (clock_mode) {
 #ifdef CONFIG_CSRC_R4K
-	case VDSO_CLOCK_R4K:
-		cycle_now = read_r4k_count();
-		break;
+	if (clock_mode == VDSO_CLOCKMODE_R4K)
+		return read_r4k_count();
 #endif
 #ifdef CONFIG_CLKSRC_MIPS_GIC
-	case VDSO_CLOCK_GIC:
-		cycle_now = read_gic_count(data);
-		break;
+	if (clock_mode == VDSO_CLOCKMODE_GIC)
+		return read_gic_count(get_vdso_data());
 #endif
-	default:
-		cycle_now = __VDSO_USE_SYSCALL;
-		break;
-	}
-
-	return cycle_now;
+	/*
+	 * Core checks mode already. So this raced against a concurrent
+	 * update. Return something. Core will do another round see the
+	 * change and fallback to syscall.
+	 */
+	return 0;
 }
 
 static inline bool mips_vdso_hres_capable(void)

arch/mips/include/asm/vdso/vsyscall.h

@@ -19,15 +19,6 @@ struct vdso_data *__mips_get_k_vdso_data(void)
 }
 #define __arch_get_k_vdso_data __mips_get_k_vdso_data
 
-static __always_inline
-int __mips_get_clock_mode(struct timekeeper *tk)
-{
-	u32 clock_mode = tk->tkr_mono.clock->archdata.vdso_clock_mode;
-
-	return clock_mode;
-}
-#define __arch_get_clock_mode __mips_get_clock_mode
-
 /* The asm-generic header needs to be included after the definitions above */
 #include <asm-generic/vdso/vsyscall.h>
 

arch/mips/kernel/csrc-r4k.c

@@ -78,7 +78,7 @@ int __init init_r4k_clocksource(void)
 	 * by the VDSO (HWREna is configured by configure_hwrena()).
 	 */
 	if (cpu_has_mips_r2_r6 && rdhwr_count_usable())
-		clocksource_mips.archdata.vdso_clock_mode = VDSO_CLOCK_R4K;
+		clocksource_mips.vdso_clock_mode = VDSO_CLOCKMODE_R4K;
 
 	clocksource_register_hz(&clocksource_mips, mips_hpt_frequency);
 

drivers/clocksource/mips-gic-timer.c

@@ -155,10 +155,10 @@ static u64 gic_hpt_read(struct clocksource *cs)
 }
 
 static struct clocksource gic_clocksource = {
-	.name		= "GIC",
-	.read		= gic_hpt_read,
-	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
-	.archdata	= { .vdso_clock_mode = VDSO_CLOCK_GIC },
+	.name			= "GIC",
+	.read			= gic_hpt_read,
+	.flags			= CLOCK_SOURCE_IS_CONTINUOUS,
+	.vdso_clock_mode	= VDSO_CLOCKMODE_GIC,
 };
 
 static int __init __gic_clocksource_init(void)