Commit 954ffcb3 authored by KAMEZAWA Hiroyuki's avatar KAMEZAWA Hiroyuki Committed by Linus Torvalds
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flush icache before set_pte() on ia64: flush icache at set_pte 

Current ia64 kernel flushes icache by lazy_mmu_prot_update() *after*
set_pte().  This is too late.  This patch removes lazy_mmu_prot_update and
add modfied set_pte() for flushing if necessary.

This patch flush icache of a page when
	new pte has exec bit.
	&& new pte has present bit
	&& new pte is user's page.
	&& (old *ptep is not present
            || new pte's pfn is not same to old *ptep's ptn)
	&& new pte's page has no Pg_arch_1 bit.
	   Pg_arch_1 is set when a page is cache consistent.

I think this condition checks are much easier to understand than considering
"Where sync_icache_dcache() should be inserted ?".

pte_user() for ia64 was removed by http://lkml.org/lkml/2007/6/12/67

 as
clean-up. So, I added it again.

Signed-off-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 97ee0524

Documentation/cachetlb.txt

+0 −6
Original line number Diff line number Diff line
@@ -133,12 +133,6 @@ changes occur: 
	The ia64 sn2 platform is one example of a platform

	that uses this interface.



8) void lazy_mmu_prot_update(pte_t pte)

	This interface is called whenever the protection on

	any user PTEs change.  This interface provides a notification

	to architecture specific code to take appropriate action.





Next, we have the cache flushing interfaces.  In general, when Linux

is changing an existing virtual-->physical mapping to a new value,

the sequence will be in one of the following forms:

arch/ia64/mm/init.c

+1 −4
Original line number Diff line number Diff line
@@ -54,15 +54,12 @@ struct page *zero_page_memmap_ptr; /* map entry for zero page */ 
EXPORT_SYMBOL(zero_page_memmap_ptr);



void

lazy_mmu_prot_update (pte_t pte)

__ia64_sync_icache_dcache (pte_t pte)

{

	unsigned long addr;

	struct page *page;

	unsigned long order;



	if (!pte_exec(pte))

		return;				/* not an executable page... */



	page = pte_page(pte);

	addr = (unsigned long) page_address(page);

include/asm-generic/pgtable.h

+0 −4
Original line number Diff line number Diff line
@@ -125,10 +125,6 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres 
#define pgd_offset_gate(mm, addr)	pgd_offset(mm, addr)

#endif



#ifndef __HAVE_ARCH_LAZY_MMU_PROT_UPDATE

#define lazy_mmu_prot_update(pte)	do { } while (0)

#endif



#ifndef __HAVE_ARCH_MOVE_PTE

#define move_pte(pte, prot, old_addr, new_addr)	(pte)

#endif

include/asm-ia64/pgtable.h

+31 −13
Original line number Diff line number Diff line
@@ -223,12 +223,6 @@ ia64_phys_addr_valid (unsigned long addr) 
 * page table.

 */



/*

 * On some architectures, special things need to be done when setting

 * the PTE in a page table.  Nothing special needs to be on IA-64.

 */

#define set_pte(ptep, pteval)	(*(ptep) = (pteval))

#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)



#define VMALLOC_START		(RGN_BASE(RGN_GATE) + 0x200000000UL)

#ifdef CONFIG_VIRTUAL_MEM_MAP
@@ -320,6 +314,36 @@ ia64_phys_addr_valid (unsigned long addr) 
#define pte_mkdirty(pte)	(__pte(pte_val(pte) | _PAGE_D))

#define pte_mkhuge(pte)		(__pte(pte_val(pte)))



/*

 * Because ia64's Icache and Dcache is not coherent (on a cpu), we need to

 * sync icache and dcache when we insert *new* executable page.

 *  __ia64_sync_icache_dcache() check Pg_arch_1 bit and flush icache

 * if necessary.

 *

 *  set_pte() is also called by the kernel, but we can expect that the kernel

 *  flushes icache explicitly if necessary.

 */

#define pte_present_exec_user(pte)\

	((pte_val(pte) & (_PAGE_P | _PAGE_PL_MASK | _PAGE_AR_RX)) == \

		(_PAGE_P | _PAGE_PL_3 | _PAGE_AR_RX))



extern void __ia64_sync_icache_dcache(pte_t pteval);

static inline void set_pte(pte_t *ptep, pte_t pteval)

{

	/* page is present && page is user  && page is executable

	 * && (page swapin or new page or page migraton

	 *	|| copy_on_write with page copying.)

	 */

	if (pte_present_exec_user(pteval) &&

	    (!pte_present(*ptep) ||

		pte_pfn(*ptep) != pte_pfn(pteval)))

		/* load_module() calles flush_icache_range() explicitly*/

		__ia64_sync_icache_dcache(pteval);

	*ptep = pteval;

}



#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)



/*

 * Make page protection values cacheable, uncacheable, or write-

 * combining.  Note that "protection" is really a misnomer here as the
@@ -489,12 +513,6 @@ extern struct page *zero_page_memmap_ptr; 
#define HUGETLB_PGDIR_MASK	(~(HUGETLB_PGDIR_SIZE-1))

#endif



/*

 * IA-64 doesn't have any external MMU info: the page tables contain all the necessary

 * information.  However, we use this routine to take care of any (delayed) i-cache

 * flushing that may be necessary.

 */

extern void lazy_mmu_prot_update (pte_t pte);



#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS

/*
@@ -584,7 +602,7 @@ extern void lazy_mmu_prot_update (pte_t pte); 
#define __HAVE_ARCH_PTEP_SET_WRPROTECT

#define __HAVE_ARCH_PTE_SAME

#define __HAVE_ARCH_PGD_OFFSET_GATE

#define __HAVE_ARCH_LAZY_MMU_PROT_UPDATE





#ifndef CONFIG_PGTABLE_4

#include <asm-generic/pgtable-nopud.h>

mm/hugetlb.c

+0 −2
Original line number Diff line number Diff line
@@ -355,7 +355,6 @@ static void set_huge_ptep_writable(struct vm_area_struct *vma, 
	entry = pte_mkwrite(pte_mkdirty(*ptep));

	if (ptep_set_access_flags(vma, address, ptep, entry, 1)) {

		update_mmu_cache(vma, address, entry);

		lazy_mmu_prot_update(entry);

	}

}
@@ -708,7 +707,6 @@ void hugetlb_change_protection(struct vm_area_struct *vma, 
			pte = huge_ptep_get_and_clear(mm, address, ptep);

			pte = pte_mkhuge(pte_modify(pte, newprot));

			set_huge_pte_at(mm, address, ptep, pte);

			lazy_mmu_prot_update(pte);

		}

	}

	spin_unlock(&mm->page_table_lock);

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