x86/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> (VDSO parts)
Acked-by: Juergen Gross <jgross@suse.com> (Xen parts)
Acked-by: Paolo Bonzini <pbonzini@redhat.com> (KVM parts)
Link: https://lkml.kernel.org/r/20200207124403.152039903@linutronix.de

arch/x86/Kconfig

@@ -57,7 +57,6 @@ config X86
 	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
 	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
 	select ARCH_32BIT_OFF_T			if X86_32
-	select ARCH_CLOCKSOURCE_DATA
 	select ARCH_CLOCKSOURCE_INIT
 	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
 	select ARCH_HAS_DEBUG_VIRTUAL
@@ -126,6 +125,7 @@ config X86
 	select GENERIC_STRNLEN_USER
 	select GENERIC_TIME_VSYSCALL
 	select GENERIC_GETTIMEOFDAY
+	select GENERIC_VDSO_CLOCK_MODE
 	select GENERIC_VDSO_TIME_NS
 	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
 	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64

arch/x86/entry/vdso/vma.c

@@ -221,7 +221,7 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
 	} else if (sym_offset == image->sym_pvclock_page) {
 		struct pvclock_vsyscall_time_info *pvti =
 			pvclock_get_pvti_cpu0_va();
-		if (pvti && vclock_was_used(VCLOCK_PVCLOCK)) {
+		if (pvti && vclock_was_used(VDSO_CLOCKMODE_PVCLOCK)) {
 			return vmf_insert_pfn_prot(vma, vmf->address,
 					__pa(pvti) >> PAGE_SHIFT,
 					pgprot_decrypted(vma->vm_page_prot));
@@ -229,7 +229,7 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
 	} else if (sym_offset == image->sym_hvclock_page) {
 		struct ms_hyperv_tsc_page *tsc_pg = hv_get_tsc_page();
 
-		if (tsc_pg && vclock_was_used(VCLOCK_HVCLOCK))
+		if (tsc_pg && vclock_was_used(VDSO_CLOCKMODE_HVCLOCK))
 			return vmf_insert_pfn(vma, vmf->address,
 					virt_to_phys(tsc_pg) >> PAGE_SHIFT);
 	} else if (sym_offset == image->sym_timens_page) {
@@ -447,7 +447,7 @@ __setup("vdso=", vdso_setup);
 
 static int __init init_vdso(void)
 {
-	BUILD_BUG_ON(VCLOCK_MAX >= 32);
+	BUILD_BUG_ON(VDSO_CLOCKMODE_MAX >= 32);
 
 	init_vdso_image(&vdso_image_64);
 

arch/x86/include/asm/clocksource.h

@@ -4,15 +4,10 @@
 #ifndef _ASM_X86_CLOCKSOURCE_H
 #define _ASM_X86_CLOCKSOURCE_H
 
-#define VCLOCK_NONE	0	/* No vDSO clock available.		*/
-#define VCLOCK_TSC	1	/* vDSO should use vread_tsc.		*/
-#define VCLOCK_PVCLOCK	2	/* vDSO should use vread_pvclock.	*/
-#define VCLOCK_HVCLOCK	3	/* vDSO should use vread_hvclock.	*/
-#define VCLOCK_MAX	3
-
-struct arch_clocksource_data {
-	int vclock_mode;
-};
+#define VDSO_ARCH_CLOCKMODES	\
+	VDSO_CLOCKMODE_TSC,	\
+	VDSO_CLOCKMODE_PVCLOCK,	\
+	VDSO_CLOCKMODE_HVCLOCK
 
 extern unsigned int vclocks_used;
 

arch/x86/include/asm/mshyperv.h

@@ -46,9 +46,9 @@ typedef int (*hyperv_fill_flush_list_func)(
 #define hv_set_reference_tsc(val) \
 	wrmsrl(HV_X64_MSR_REFERENCE_TSC, val)
 #define hv_set_clocksource_vdso(val) \
-	((val).archdata.vclock_mode = VCLOCK_HVCLOCK)
+	((val).vdso_clock_mode = VDSO_CLOCKMODE_HVCLOCK)
 #define hv_enable_vdso_clocksource() \
-	vclocks_set_used(VCLOCK_HVCLOCK);
+	vclocks_set_used(VDSO_CLOCKMODE_HVCLOCK);
 #define hv_get_raw_timer() rdtsc_ordered()
 
 void hyperv_callback_vector(void);

arch/x86/include/asm/vdso/gettimeofday.h

@@ -243,7 +243,7 @@ static u64 vread_hvclock(void)
 
 static inline u64 __arch_get_hw_counter(s32 clock_mode)
 {
-	if (likely(clock_mode == VCLOCK_TSC))
+	if (likely(clock_mode == VDSO_CLOCKMODE_TSC))
 		return (u64)rdtsc_ordered();
 	/*
 	 * For any memory-mapped vclock type, we need to make sure that gcc
@@ -252,13 +252,13 @@ static inline u64 __arch_get_hw_counter(s32 clock_mode)
 	 * question isn't enabled, which will segfault.  Hence the barriers.
 	 */
 #ifdef CONFIG_PARAVIRT_CLOCK
-	if (clock_mode == VCLOCK_PVCLOCK) {
+	if (clock_mode == VDSO_CLOCKMODE_PVCLOCK) {
 		barrier();
 		return vread_pvclock();
 	}
 #endif
 #ifdef CONFIG_HYPERV_TIMER
-	if (clock_mode == VCLOCK_HVCLOCK) {
+	if (clock_mode == VDSO_CLOCKMODE_HVCLOCK) {
 		barrier();
 		return vread_hvclock();
 	}

arch/x86/include/asm/vdso/vsyscall.h

@@ -21,13 +21,6 @@ struct vdso_data *__x86_get_k_vdso_data(void)
 }
 #define __arch_get_k_vdso_data __x86_get_k_vdso_data
 
-static __always_inline
-int __x86_get_clock_mode(struct timekeeper *tk)
-{
-	return tk->tkr_mono.clock->archdata.vclock_mode;
-}
-#define __arch_get_clock_mode __x86_get_clock_mode
-
 /* The asm-generic header needs to be included after the definitions above */
 #include <asm-generic/vdso/vsyscall.h>
 

arch/x86/kernel/kvmclock.c

@@ -161,7 +161,7 @@ bool kvm_check_and_clear_guest_paused(void)
 
 static int kvm_cs_enable(struct clocksource *cs)
 {
-	vclocks_set_used(VCLOCK_PVCLOCK);
+	vclocks_set_used(VDSO_CLOCKMODE_PVCLOCK);
 	return 0;
 }
 
@@ -279,7 +279,7 @@ static int __init kvm_setup_vsyscall_timeinfo(void)
 	if (!(flags & PVCLOCK_TSC_STABLE_BIT))
 		return 0;
 
-	kvm_clock.archdata.vclock_mode = VCLOCK_PVCLOCK;
+	kvm_clock.vdso_clock_mode = VDSO_CLOCKMODE_PVCLOCK;
 #endif
 
 	kvmclock_init_mem();

arch/x86/kernel/pvclock.c

@@ -145,7 +145,7 @@ void pvclock_read_wallclock(struct pvclock_wall_clock *wall_clock,
 
 void pvclock_set_pvti_cpu0_va(struct pvclock_vsyscall_time_info *pvti)
 {
-	WARN_ON(vclock_was_used(VCLOCK_PVCLOCK));
+	WARN_ON(vclock_was_used(VDSO_CLOCKMODE_PVCLOCK));
 	pvti_cpu0_va = pvti;
 }
 

arch/x86/kernel/time.c

@@ -122,18 +122,12 @@ void __init time_init(void)
  */
 void clocksource_arch_init(struct clocksource *cs)
 {
-	if (cs->archdata.vclock_mode == VCLOCK_NONE)
+	if (cs->vdso_clock_mode == VDSO_CLOCKMODE_NONE)
 		return;
 
-	if (cs->archdata.vclock_mode > VCLOCK_MAX) {
-		pr_warn("clocksource %s registered with invalid vclock_mode %d. Disabling vclock.\n",
-			cs->name, cs->archdata.vclock_mode);
-		cs->archdata.vclock_mode = VCLOCK_NONE;
-	}
-
 	if (cs->mask != CLOCKSOURCE_MASK(64)) {
-		pr_warn("clocksource %s registered with invalid mask %016llx. Disabling vclock.\n",
+		pr_warn("clocksource %s registered with invalid mask %016llx for VDSO. Disabling VDSO support.\n",
 			cs->name, cs->mask);
-		cs->archdata.vclock_mode = VCLOCK_NONE;
+		cs->vdso_clock_mode = VDSO_CLOCKMODE_NONE;
 	}
 }

arch/x86/kernel/tsc.c

@@ -1110,7 +1110,7 @@ static void tsc_cs_tick_stable(struct clocksource *cs)
 
 static int tsc_cs_enable(struct clocksource *cs)
 {
-	vclocks_set_used(VCLOCK_TSC);
+	vclocks_set_used(VDSO_CLOCKMODE_TSC);
 	return 0;
 }
 
@@ -1124,7 +1124,7 @@ static struct clocksource clocksource_tsc_early = {
 	.mask			= CLOCKSOURCE_MASK(64),
 	.flags			= CLOCK_SOURCE_IS_CONTINUOUS |
 				  CLOCK_SOURCE_MUST_VERIFY,
-	.archdata		= { .vclock_mode = VCLOCK_TSC },
+	.vdso_clock_mode	= VDSO_CLOCKMODE_TSC,
 	.enable			= tsc_cs_enable,
 	.resume			= tsc_resume,
 	.mark_unstable		= tsc_cs_mark_unstable,
@@ -1145,7 +1145,7 @@ static struct clocksource clocksource_tsc = {
 	.flags			= CLOCK_SOURCE_IS_CONTINUOUS |
 				  CLOCK_SOURCE_VALID_FOR_HRES |
 				  CLOCK_SOURCE_MUST_VERIFY,
-	.archdata		= { .vclock_mode = VCLOCK_TSC },
+	.vdso_clock_mode	= VDSO_CLOCKMODE_TSC,
 	.enable			= tsc_cs_enable,
 	.resume			= tsc_resume,
 	.mark_unstable		= tsc_cs_mark_unstable,

arch/x86/kvm/trace.h

@@ -815,8 +815,8 @@ TRACE_EVENT(kvm_write_tsc_offset,
 #ifdef CONFIG_X86_64
 
 #define host_clocks					\
-	{VCLOCK_NONE, "none"},				\
-	{VCLOCK_TSC,  "tsc"}				\
+	{VDSO_CLOCKMODE_NONE, "none"},			\
+	{VDSO_CLOCKMODE_TSC,  "tsc"}			\
 
 TRACE_EVENT(kvm_update_master_clock,
 	TP_PROTO(bool use_master_clock, unsigned int host_clock, bool offset_matched),

arch/x86/kvm/x86.c

@@ -1631,7 +1631,7 @@ static void update_pvclock_gtod(struct timekeeper *tk)
 	write_seqcount_begin(&vdata->seq);
 
 	/* copy pvclock gtod data */
-	vdata->clock.vclock_mode	= tk->tkr_mono.clock->archdata.vclock_mode;
+	vdata->clock.vclock_mode	= tk->tkr_mono.clock->vdso_clock_mode;
 	vdata->clock.cycle_last		= tk->tkr_mono.cycle_last;
 	vdata->clock.mask		= tk->tkr_mono.mask;
 	vdata->clock.mult		= tk->tkr_mono.mult;
@@ -1639,7 +1639,7 @@ static void update_pvclock_gtod(struct timekeeper *tk)
 	vdata->clock.base_cycles	= tk->tkr_mono.xtime_nsec;
 	vdata->clock.offset		= tk->tkr_mono.base;
 
-	vdata->raw_clock.vclock_mode	= tk->tkr_raw.clock->archdata.vclock_mode;
+	vdata->raw_clock.vclock_mode	= tk->tkr_raw.clock->vdso_clock_mode;
 	vdata->raw_clock.cycle_last	= tk->tkr_raw.cycle_last;
 	vdata->raw_clock.mask		= tk->tkr_raw.mask;
 	vdata->raw_clock.mult		= tk->tkr_raw.mult;
@@ -1840,7 +1840,7 @@ static u64 compute_guest_tsc(struct kvm_vcpu *vcpu, s64 kernel_ns)
 
 static inline int gtod_is_based_on_tsc(int mode)
 {
-	return mode == VCLOCK_TSC || mode == VCLOCK_HVCLOCK;
+	return mode == VDSO_CLOCKMODE_TSC || mode == VDSO_CLOCKMODE_HVCLOCK;
 }
 
 static void kvm_track_tsc_matching(struct kvm_vcpu *vcpu)
@@ -1933,7 +1933,7 @@ static inline bool kvm_check_tsc_unstable(void)
 	 * TSC is marked unstable when we're running on Hyper-V,
 	 * 'TSC page' clocksource is good.
 	 */
-	if (pvclock_gtod_data.clock.vclock_mode == VCLOCK_HVCLOCK)
+	if (pvclock_gtod_data.clock.vclock_mode == VDSO_CLOCKMODE_HVCLOCK)
 		return false;
 #endif
 	return check_tsc_unstable();
@@ -2088,30 +2088,30 @@ static inline u64 vgettsc(struct pvclock_clock *clock, u64 *tsc_timestamp,
 	u64 tsc_pg_val;
 
 	switch (clock->vclock_mode) {
-	case VCLOCK_HVCLOCK:
+	case VDSO_CLOCKMODE_HVCLOCK:
 		tsc_pg_val = hv_read_tsc_page_tsc(hv_get_tsc_page(),
 						  tsc_timestamp);
 		if (tsc_pg_val != U64_MAX) {
 			/* TSC page valid */
-			*mode = VCLOCK_HVCLOCK;
+			*mode = VDSO_CLOCKMODE_HVCLOCK;
 			v = (tsc_pg_val - clock->cycle_last) &
 				clock->mask;
 		} else {
 			/* TSC page invalid */
-			*mode = VCLOCK_NONE;
+			*mode = VDSO_CLOCKMODE_NONE;
 		}
 		break;
-	case VCLOCK_TSC:
-		*mode = VCLOCK_TSC;
+	case VDSO_CLOCKMODE_TSC:
+		*mode = VDSO_CLOCKMODE_TSC;
 		*tsc_timestamp = read_tsc();
 		v = (*tsc_timestamp - clock->cycle_last) &
 			clock->mask;
 		break;
 	default:
-		*mode = VCLOCK_NONE;
+		*mode = VDSO_CLOCKMODE_NONE;
 	}
 
-	if (*mode == VCLOCK_NONE)
+	if (*mode == VDSO_CLOCKMODE_NONE)
 		*tsc_timestamp = v = 0;
 
 	return v * clock->mult;

arch/x86/xen/time.c

@@ -147,7 +147,7 @@ static struct notifier_block xen_pvclock_gtod_notifier = {
 
 static int xen_cs_enable(struct clocksource *cs)
 {
-	vclocks_set_used(VCLOCK_PVCLOCK);
+	vclocks_set_used(VDSO_CLOCKMODE_PVCLOCK);
 	return 0;
 }
 
@@ -419,12 +419,13 @@ void xen_restore_time_memory_area(void)
 	ret = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_time_memory_area, 0, &t);
 
 	/*
-	 * We don't disable VCLOCK_PVCLOCK entirely if it fails to register the
-	 * secondary time info with Xen or if we migrated to a host without the
-	 * necessary flags. On both of these cases what happens is either
-	 * process seeing a zeroed out pvti or seeing no PVCLOCK_TSC_STABLE_BIT
-	 * bit set. Userspace checks the latter and if 0, it discards the data
-	 * in pvti and fallbacks to a system call for a reliable timestamp.
+	 * We don't disable VDSO_CLOCKMODE_PVCLOCK entirely if it fails to
+	 * register the secondary time info with Xen or if we migrated to a
+	 * host without the necessary flags. On both of these cases what
+	 * happens is either process seeing a zeroed out pvti or seeing no
+	 * PVCLOCK_TSC_STABLE_BIT bit set. Userspace checks the latter and
+	 * if 0, it discards the data in pvti and fallbacks to a system
+	 * call for a reliable timestamp.
 	 */
 	if (ret != 0)
 		pr_notice("Cannot restore secondary vcpu_time_info (err %d)",
@@ -450,7 +451,7 @@ static void xen_setup_vsyscall_time_info(void)
 
 	ret = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_time_memory_area, 0, &t);
 	if (ret) {
-		pr_notice("xen: VCLOCK_PVCLOCK not supported (err %d)\n", ret);
+		pr_notice("xen: VDSO_CLOCKMODE_PVCLOCK not supported (err %d)\n", ret);
 		free_page((unsigned long)ti);
 		return;
 	}
@@ -467,14 +468,14 @@ static void xen_setup_vsyscall_time_info(void)
 		if (!ret)
 			free_page((unsigned long)ti);
 
-		pr_notice("xen: VCLOCK_PVCLOCK not supported (tsc unstable)\n");
+		pr_notice("xen: VDSO_CLOCKMODE_PVCLOCK not supported (tsc unstable)\n");
 		return;
 	}
 
 	xen_clock = ti;
 	pvclock_set_pvti_cpu0_va(xen_clock);
 
-	xen_clocksource.archdata.vclock_mode = VCLOCK_PVCLOCK;
+	xen_clocksource.vdso_clock_mode = VDSO_CLOCKMODE_PVCLOCK;
 }
 
 static void __init xen_time_init(void)