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linux/include/asm-powerpc/tlbflush.h
Benjamin Herrenschmidt a741e67969 [POWERPC] Make tlb flush batch use lazy MMU mode 
The current tlb flush code on powerpc 64 bits has a subtle race since we
lost the page table lock due to the possible faulting in of new PTEs
after a previous one has been removed but before the corresponding hash
entry has been evicted, which can leads to all sort of fatal problems.

This patch reworks the batch code completely. It doesn't use the mmu_gather
stuff anymore. Instead, we use the lazy mmu hooks that were added by the
paravirt code. They have the nice property that the enter/leave lazy mmu
mode pair is always fully contained by the PTE lock for a given range
of PTEs. Thus we can guarantee that all batches are flushed on a given
CPU before it drops that lock.

We also generalize batching for any PTE update that require a flush.

Batching is now enabled on a CPU by arch_enter_lazy_mmu_mode() and
disabled by arch_leave_lazy_mmu_mode(). The code epects that this is
always contained within a PTE lock section so no preemption can happen
and no PTE insertion in that range from another CPU. When batching
is enabled on a CPU, every PTE updates that need a hash flush will
use the batch for that flush.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-04-13 04:09:38 +10:00

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#ifndef _ASM_POWERPC_TLBFLUSH_H
#define _ASM_POWERPC_TLBFLUSH_H
/*
* TLB flushing:
*
* - flush_tlb_mm(mm) flushes the specified mm context TLB's
* - flush_tlb_page(vma, vmaddr) flushes one page
* - flush_tlb_page_nohash(vma, vmaddr) flushes one page if SW loaded TLB
* - flush_tlb_range(vma, start, end) flushes a range of pages
* - flush_tlb_kernel_range(start, end) flushes a range of kernel pages
* - flush_tlb_pgtables(mm, start, end) flushes a range of page tables
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifdef __KERNEL__
struct mm_struct;
#ifdef CONFIG_PPC64
#include <linux/percpu.h>
#include <asm/page.h>
#define PPC64_TLB_BATCH_NR 192
struct ppc64_tlb_batch {
int active;
unsigned long index;
struct mm_struct *mm;
real_pte_t pte[PPC64_TLB_BATCH_NR];
unsigned long vaddr[PPC64_TLB_BATCH_NR];
unsigned int psize;
};
DECLARE_PER_CPU(struct ppc64_tlb_batch, ppc64_tlb_batch);
extern void __flush_tlb_pending(struct ppc64_tlb_batch *batch);
extern void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, unsigned long pte, int huge);
#define __HAVE_ARCH_ENTER_LAZY_MMU_MODE
static inline void arch_enter_lazy_mmu_mode(void)
{
struct ppc64_tlb_batch *batch = &__get_cpu_var(ppc64_tlb_batch);
batch->active = 1;
}
static inline void arch_leave_lazy_mmu_mode(void)
{
struct ppc64_tlb_batch *batch = &__get_cpu_var(ppc64_tlb_batch);
if (batch->index)
__flush_tlb_pending(batch);
batch->active = 0;
}
#define arch_flush_lazy_mmu_mode() do {} while (0)
extern void flush_hash_page(unsigned long va, real_pte_t pte, int psize,
int local);
extern void flush_hash_range(unsigned long number, int local);
#else /* CONFIG_PPC64 */
#include <linux/mm.h>
extern void _tlbie(unsigned long address);
extern void _tlbia(void);
/*
* TODO: (CONFIG_FSL_BOOKE) determine if flush_tlb_range &
* flush_tlb_kernel_range are best implemented as tlbia vs
* specific tlbie's
*/
#if (defined(CONFIG_4xx) && !defined(CONFIG_44x)) || defined(CONFIG_8xx)
#define flush_tlb_pending() asm volatile ("tlbia; sync" : : : "memory")
#elif defined(CONFIG_4xx) || defined(CONFIG_FSL_BOOKE)
#define flush_tlb_pending() _tlbia()
#endif
/*
* This gets called at the end of handling a page fault, when
* the kernel has put a new PTE into the page table for the process.
* We use it to ensure coherency between the i-cache and d-cache
* for the page which has just been mapped in.
* On machines which use an MMU hash table, we use this to put a
* corresponding HPTE into the hash table ahead of time, instead of
* waiting for the inevitable extra hash-table miss exception.
*/
extern void update_mmu_cache(struct vm_area_struct *, unsigned long, pte_t);
#endif /* CONFIG_PPC64 */
#if defined(CONFIG_PPC64) || defined(CONFIG_4xx) || \
defined(CONFIG_FSL_BOOKE) || defined(CONFIG_8xx)
static inline void flush_tlb_mm(struct mm_struct *mm)
{
}
static inline void flush_tlb_page(struct vm_area_struct *vma,
unsigned long vmaddr)
{
#ifndef CONFIG_PPC64
_tlbie(vmaddr);
#endif
}
static inline void flush_tlb_page_nohash(struct vm_area_struct *vma,
unsigned long vmaddr)
{
#ifndef CONFIG_PPC64
_tlbie(vmaddr);
#endif
}
static inline void flush_tlb_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end)
{
}
static inline void flush_tlb_kernel_range(unsigned long start,
unsigned long end)
{
}
#else /* 6xx, 7xx, 7xxx cpus */
extern void flush_tlb_mm(struct mm_struct *mm);
extern void flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr);
extern void flush_tlb_page_nohash(struct vm_area_struct *vma, unsigned long addr);
extern void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end);
extern void flush_tlb_kernel_range(unsigned long start, unsigned long end);
#endif
/*
* This is called in munmap when we have freed up some page-table
* pages. We don't need to do anything here, there's nothing special
* about our page-table pages. -- paulus
*/
static inline void flush_tlb_pgtables(struct mm_struct *mm,
unsigned long start, unsigned long end)
{
}
#endif /*__KERNEL__ */
#endif /* _ASM_POWERPC_TLBFLUSH_H */
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