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x86/paravirt: make arch_flush_lazy_mmu/cpu disable preemption 

Impact: avoid access to percpu vars in preempible context

They are intended to be used whenever there's the possibility
that there's some stale state which is going to be overwritten
with a queued update, or to force a state change when we may be
in lazy mode.  Either way, we could end up calling it with
preemption enabled, so wrap the functions in their own little
preempt-disable section so they can be safely called in any
context (though preemption should never be enabled if we're actually
in a lazy state).

(Move out of line to avoid #include dependencies.)
    
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
hifive-unleashed-5.1
Jeremy Fitzhardinge 2009-02-12 10:02:56 -08:00 committed by Thomas Gleixner
parent be03d9e802
commit d85cf93da6
2 changed files with 26 additions and 15 deletions
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17
arch/x86/include/asm/paravirt.h
View File

@ -1352,14 +1352,7 @@ static inline void arch_leave_lazy_cpu_mode(void)
PVOP_VCALL0(pv_cpu_ops.lazy_mode.leave);
}
static inline void arch_flush_lazy_cpu_mode(void)
{
if (unlikely(paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU)) {
arch_leave_lazy_cpu_mode();
arch_enter_lazy_cpu_mode();
}
}
void arch_flush_lazy_cpu_mode(void);
#define __HAVE_ARCH_ENTER_LAZY_MMU_MODE
static inline void arch_enter_lazy_mmu_mode(void)
@ -1372,13 +1365,7 @@ static inline void arch_leave_lazy_mmu_mode(void)
PVOP_VCALL0(pv_mmu_ops.lazy_mode.leave);
}
static inline void arch_flush_lazy_mmu_mode(void)
{
if (unlikely(paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU)) {
arch_leave_lazy_mmu_mode();
arch_enter_lazy_mmu_mode();
}
}
void arch_flush_lazy_mmu_mode(void);
static inline void __set_fixmap(unsigned /* enum fixed_addresses */ idx,
unsigned long phys, pgprot_t flags)

24
arch/x86/kernel/paravirt.c
View File

@ -268,6 +268,30 @@ enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
return __get_cpu_var(paravirt_lazy_mode);
}
void arch_flush_lazy_mmu_mode(void)
{
preempt_disable();
if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
arch_leave_lazy_mmu_mode();
arch_enter_lazy_mmu_mode();
}
preempt_enable();
}
void arch_flush_lazy_cpu_mode(void)
{
preempt_disable();
if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
arch_leave_lazy_cpu_mode();
arch_enter_lazy_cpu_mode();
}
preempt_enable();
}
struct pv_info pv_info = {
.name = "bare hardware",
.paravirt_enabled = 0,