/******************************************************************************
* flushtlb.h
*
* TLB flushes are timestamped using a global virtual 'clock' which ticks
* on any TLB flush on any processor.
*
* Copyright (c) 2003-2004, K A Fraser
*/
#ifndef __FLUSHTLB_H__
#define __FLUSHTLB_H__
#include <xen/config.h>
#include <xen/smp.h>
/* The current time as shown by the virtual TLB clock. */
extern u32 tlbflush_clock;
/* Time at which each CPU's TLB was last flushed. */
extern u32 tlbflush_time[NR_CPUS];
#define tlbflush_current_time() tlbflush_clock
/*
* @cpu_stamp is the timestamp at last TLB flush for the CPU we are testing.
* @lastuse_stamp is a timestamp taken when the PFN we are testing was last
* used for a purpose that may have caused the CPU's TLB to become tainted.
*/
static inline int NEED_FLUSH(u32 cpu_stamp, u32 lastuse_stamp)
{
u32 curr_time = tlbflush_current_time();
/*
* Two cases:
* 1. During a wrap, the clock ticks over to 0 while CPUs catch up. For
* safety during this period, we force a flush if @curr_time == 0.
* 2. Otherwise, we look to see if @cpu_stamp <= @lastuse_stamp.
* To detect false positives because @cpu_stamp has wrapped, we
* also check @curr_time. If less than @lastuse_stamp we definitely
* wrapped, so there's no need for a flush (one is forced every wrap).
*/
return ((curr_time == 0) ||
((cpu_stamp <= lastuse_stamp) &&
(lastuse_stamp <= curr_time)));
}
extern void new_tlbflush_clock_period(void);
/* Read pagetable base. */
static inline unsigned long read_cr3(void)
{
unsigned long cr3;
__asm__ __volatile__ (
"mov"__OS" %%cr3, %0" : "=r" (cr3) : );
return cr3;
}
/* Write pagetable base and implicitly tick the tlbflush clock. */
extern void write_cr3(unsigned long cr3);
/*
* TLB flushing:
*
* - flush_tlb() flushes the current mm struct TLBs
* - flush_tlb_all() flushes all processes TLBs
* - flush_tlb_pgtables(mm, start, end) flushes a range of page tables
*
* ..but the i386 has somewhat limited tlb flushing capabilities,
* and page-granular flushes are available only on i486 and up.
*/
#define __flush_tlb() \
do { \
unsigned long cr3 = read_cr3(); \
write_cr3(cr3); \
} while ( 0 )
#ifndef CONFIG_SMP
#define flush_tlb() __flush_tlb()
#define flush_tlb_all() __flush_tlb()
#define flush_tlb_all_pge() __flush_tlb_pge()
#define local_flush_tlb() __flush_tlb()
#define flush_tlb_cpu(_cpu) __flush_tlb()
#define flush_tlb_mask(_mask) __flush_tlb()
#define try_flush_tlb_mask(_mask) __flush_tlb()
#else
#include <xen/smp.h>
extern int try_flush_tlb_mask(unsigned long mask);
extern void flush_tlb_mask(unsigned long mask);
extern void flush_tlb_all_pge(void);
#define flush_tlb() __flush_tlb()
#define flush_tlb_all() flush_tlb_mask((1 << smp_num_cpus) - 1)
#define local_flush_tlb() __flush_tlb()
#define flush_tlb_cpu(_cpu) flush_tlb_mask(1 << (_cpu))
#endif
#endif /* __FLUSHTLB_H__ */
