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clocksource/drivers/hyperv: Allocate Hyper-V TSC page statically 

Prepare to add Hyper-V sched clock callback and move Hyper-V Reference TSC
initialization much earlier in the boot process.  Earlier initialization is
needed so that it happens while the timestamp value is still 0 and no
discontinuity in the timestamp will occur when pv_ops.time.sched_clock
calculates its offset.
    
The earlier initialization requires that the Hyper-V TSC page be allocated
statically instead of with vmalloc(), so fixup the references to the TSC
page and the method of getting its physical address.
    
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lkml.kernel.org/r/20190814123216.32245-2-Tianyu.Lan@microsoft.com
alistair/sunxi64-5.4-dsi
Tianyu Lan 2019-08-14 20:32:15 +08:00 committed by Thomas Gleixner
parent dce3e8fd03
commit adb87ff4f9
2 changed files with 5 additions and 9 deletions
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2
arch/x86/entry/vdso/vma.c
View File

@ -122,7 +122,7 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
if (tsc_pg && vclock_was_used(VCLOCK_HVCLOCK)) if (tsc_pg && vclock_was_used(VCLOCK_HVCLOCK))
return vmf_insert_pfn(vma, vmf->address, return vmf_insert_pfn(vma, vmf->address,
vmalloc_to_pfn(tsc_pg)); virt_to_phys(tsc_pg) >> PAGE_SHIFT);
} }
return VM_FAULT_SIGBUS; return VM_FAULT_SIGBUS;

12
drivers/clocksource/hyperv_timer.c
View File

@ -214,17 +214,17 @@ EXPORT_SYMBOL_GPL(hyperv_cs);
#ifdef CONFIG_HYPERV_TSCPAGE #ifdef CONFIG_HYPERV_TSCPAGE
static struct ms_hyperv_tsc_page *tsc_pg; static struct ms_hyperv_tsc_page tsc_pg __aligned(PAGE_SIZE);
struct ms_hyperv_tsc_page *hv_get_tsc_page(void) struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
{ {
return tsc_pg; return &tsc_pg;
} }
EXPORT_SYMBOL_GPL(hv_get_tsc_page); EXPORT_SYMBOL_GPL(hv_get_tsc_page);
static u64 notrace read_hv_sched_clock_tsc(void) static u64 notrace read_hv_sched_clock_tsc(void)
{ {
u64 current_tick = hv_read_tsc_page(tsc_pg); u64 current_tick = hv_read_tsc_page(&tsc_pg);
if (current_tick == U64_MAX) if (current_tick == U64_MAX)
hv_get_time_ref_count(current_tick); hv_get_time_ref_count(current_tick);
@ -280,12 +280,8 @@ static bool __init hv_init_tsc_clocksource(void)
if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE)) if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE))
return false; return false;
tsc_pg = vmalloc(PAGE_SIZE);
if (!tsc_pg)
return false;
hyperv_cs = &hyperv_cs_tsc; hyperv_cs = &hyperv_cs_tsc;
phys_addr = page_to_phys(vmalloc_to_page(tsc_pg)); phys_addr = virt_to_phys(&tsc_pg);
/* /*
* The Hyper-V TLFS specifies to preserve the value of reserved * The Hyper-V TLFS specifies to preserve the value of reserved