[patch V2 09/17] x86/vdso: Use generic VDSO clock mode storage

From: Thomas Gleixner
Date: Fri Feb 07 2020 - 08:26:02 EST

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

Switch to the generic VDSO clock mode storage.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Juergen Gross <jgross@xxxxxxxx> (Xen parts)

---
arch/x86/Kconfig | 2 +-
arch/x86/entry/vdso/vma.c | 6 +++---
arch/x86/include/asm/clocksource.h | 13 ++++---------
arch/x86/include/asm/mshyperv.h | 4 ++--
arch/x86/include/asm/vdso/gettimeofday.h | 6 +++---
arch/x86/include/asm/vdso/vsyscall.h | 7 -------
arch/x86/kernel/kvmclock.c | 4 ++--
arch/x86/kernel/pvclock.c | 2 +-
arch/x86/kernel/time.c | 12 +++---------
arch/x86/kernel/tsc.c | 6 +++---
arch/x86/kvm/trace.h | 4 ++--
arch/x86/kvm/x86.c | 22 +++++++++++-----------
arch/x86/xen/time.c | 21 +++++++++++----------
13 files changed, 46 insertions(+), 63 deletions(-)

--- a/arch/x86/Kconfig
+++ b/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
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -221,7 +221,7 @@ static vm_fault_t vvar_fault(const struc
} 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 struc
} 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 @@ static __init int vdso_setup(char *s)

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);

--- a/arch/x86/include/asm/clocksource.h
+++ b/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;

--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -46,9 +46,9 @@ typedef int (*hyperv_fill_flush_list_fun
#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);
--- a/arch/x86/include/asm/vdso/gettimeofday.h
+++ b/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(
* 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();
}
--- a/arch/x86/include/asm/vdso/vsyscall.h
+++ b/arch/x86/include/asm/vdso/vsyscall.h
@@ -21,13 +21,6 @@ struct vdso_data *__x86_get_k_vdso_data(
}
#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>

--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -161,7 +161,7 @@ bool kvm_check_and_clear_guest_paused(vo

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_tim
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();
--- a/arch/x86/kernel/pvclock.c
+++ b/arch/x86/kernel/pvclock.c
@@ -145,7 +145,7 @@ void pvclock_read_wallclock(struct pvclo

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;
}

--- a/arch/x86/kernel/time.c
+++ b/arch/x86/kernel/time.c
@@ -114,18 +114,12 @@ 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;
}
}
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1110,7 +1110,7 @@ static void tsc_cs_tick_stable(struct cl

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_ts
.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_ts
.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,
--- a/arch/x86/kvm/trace.h
+++ b/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),
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1635,7 +1635,7 @@ static void update_pvclock_gtod(struct t
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;
@@ -1643,7 +1643,7 @@ static void update_pvclock_gtod(struct t
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;
@@ -1844,7 +1844,7 @@ static u64 compute_guest_tsc(struct kvm_

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)
@@ -1937,7 +1937,7 @@ static inline bool kvm_check_tsc_unstabl
* 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();
@@ -2092,30 +2092,30 @@ static inline u64 vgettsc(struct pvclock
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;
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -147,7 +147,7 @@ static struct notifier_block xen_pvclock

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

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
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)