[PATCH] parisc: Purge TLB entries after updating page table entry and set page accessed flag in TLB handler

[John David Anglin <dave.anglin@xxxxxxxx>]

This patch may resolve some races in TLB handling.  Hopefully, TLB 
inserts are accesses and
protected by spin lock.

If not, we may need to IPI calls and do local purges on PA 2.0.

Dave

--
John David Anglin  dave.anglin@xxxxxxxx

diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h
index fa6b7c78f18a..b86c31291f0a 100644
--- a/arch/parisc/include/asm/pgtable.h
+++ b/arch/parisc/include/asm/pgtable.h
@@ -66,9 +66,9 @@ static inline void purge_tlb_entries(struct mm_struct *mm, unsigned long addr)
 		unsigned long flags;				\
 		spin_lock_irqsave(&pa_tlb_lock, flags);		\
 		old_pte = *ptep;				\
+		set_pte(ptep, pteval);				\
 		if (pte_inserted(old_pte))			\
 			purge_tlb_entries(mm, addr);		\
-		set_pte(ptep, pteval);				\
 		spin_unlock_irqrestore(&pa_tlb_lock, flags);	\
 	} while (0)
 
@@ -202,7 +202,7 @@ static inline void purge_tlb_entries(struct mm_struct *mm, unsigned long addr)
 #define _PAGE_HUGE     (1 << xlate_pabit(_PAGE_HPAGE_BIT))
 #define _PAGE_USER     (1 << xlate_pabit(_PAGE_USER_BIT))
 
-#define _PAGE_TABLE	(_PAGE_PRESENT | _PAGE_READ | _PAGE_WRITE |  _PAGE_DIRTY | _PAGE_ACCESSED)
+#define _PAGE_TABLE	(_PAGE_PRESENT | _PAGE_READ | _PAGE_WRITE | _PAGE_DIRTY | _PAGE_ACCESSED)
 #define _PAGE_CHG_MASK	(PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
 #define _PAGE_KERNEL_RO	(_PAGE_PRESENT | _PAGE_READ | _PAGE_DIRTY | _PAGE_ACCESSED)
 #define _PAGE_KERNEL_EXEC	(_PAGE_KERNEL_RO | _PAGE_EXEC)
@@ -227,22 +227,22 @@ static inline void purge_tlb_entries(struct mm_struct *mm, unsigned long addr)
 
 #ifndef __ASSEMBLY__
 
-#define PAGE_NONE	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
-#define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | _PAGE_WRITE | _PAGE_ACCESSED)
+#define PAGE_NONE	__pgprot(_PAGE_PRESENT | _PAGE_USER)
+#define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | _PAGE_WRITE)
 /* Others seem to make this executable, I don't know if that's correct
    or not.  The stack is mapped this way though so this is necessary
    in the short term - dhd@xxxxxxxxxxxxx, 2000-08-08 */
-#define PAGE_READONLY	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | _PAGE_ACCESSED)
-#define PAGE_WRITEONLY  __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITE | _PAGE_ACCESSED)
-#define PAGE_EXECREAD   __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | _PAGE_EXEC |_PAGE_ACCESSED)
+#define PAGE_READONLY	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ)
+#define PAGE_WRITEONLY  __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITE)
+#define PAGE_EXECREAD   __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | _PAGE_EXEC)
 #define PAGE_COPY       PAGE_EXECREAD
-#define PAGE_RWX        __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | _PAGE_WRITE | _PAGE_EXEC |_PAGE_ACCESSED)
+#define PAGE_RWX        __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | _PAGE_WRITE | _PAGE_EXEC)
 #define PAGE_KERNEL	__pgprot(_PAGE_KERNEL)
 #define PAGE_KERNEL_EXEC	__pgprot(_PAGE_KERNEL_EXEC)
 #define PAGE_KERNEL_RWX	__pgprot(_PAGE_KERNEL_RWX)
 #define PAGE_KERNEL_RO	__pgprot(_PAGE_KERNEL_RO)
 #define PAGE_KERNEL_UNC	__pgprot(_PAGE_KERNEL | _PAGE_NO_CACHE)
-#define PAGE_GATEWAY    __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED | _PAGE_GATEWAY| _PAGE_READ)
+#define PAGE_GATEWAY    __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_GATEWAY| _PAGE_READ)
 
 
 /*
@@ -479,8 +479,8 @@ static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned
 		spin_unlock_irqrestore(&pa_tlb_lock, flags);
 		return 0;
 	}
-	purge_tlb_entries(vma->vm_mm, addr);
 	set_pte(ptep, pte_mkold(pte));
+	purge_tlb_entries(vma->vm_mm, addr);
 	spin_unlock_irqrestore(&pa_tlb_lock, flags);
 	return 1;
 }
@@ -493,9 +493,9 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
 
 	spin_lock_irqsave(&pa_tlb_lock, flags);
 	old_pte = *ptep;
+	set_pte(ptep, __pte(0));
 	if (pte_inserted(old_pte))
 		purge_tlb_entries(mm, addr);
-	set_pte(ptep, __pte(0));
 	spin_unlock_irqrestore(&pa_tlb_lock, flags);
 
 	return old_pte;
@@ -505,8 +505,8 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
 {
 	unsigned long flags;
 	spin_lock_irqsave(&pa_tlb_lock, flags);
-	purge_tlb_entries(mm, addr);
 	set_pte(ptep, pte_wrprotect(*ptep));
+	purge_tlb_entries(mm, addr);
 	spin_unlock_irqrestore(&pa_tlb_lock, flags);
 }
 
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index 1b4732e20137..27944a7ebfeb 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -482,9 +482,7 @@
 	.macro		tlb_unlock0	spc,tmp
 #ifdef CONFIG_SMP
 	or,COND(=)	%r0,\spc,%r0
-	sync
-	or,COND(=)	%r0,\spc,%r0
-	stw             \spc,0(\tmp)
+	stw,ma		\spc,0(\tmp)
 #endif
 	.endm