[MIPS] Fix marking buddy of pte global for MIPS32 w/36-bit physical address

    
In case of CONFIG_64BIT_PHYS_ADDR, set_pte() and pte_clear() functions
only set _PAGE_GLOBAL bit in the pte_low field of the buddy PTEs,
forgetting to propagate ito to pte_high. Thus, the both pages might not
really be made global for the CPU (since it AND's the G-bit of the
odd / even PTEs together to decide whether they're global or not). Thus,
if only a single page is allocated via vmalloc() or ioremap(), it's not
really global for CPU (and it must be, since this is kernel mapping),
and thus its ASID is compared against the current process' one -- so,
we'll get into trouble sooner or later...  Also, pte_none() will fail
on global pages because _PAGE_GLOBAL bit is set in both pte_low and
pte_high, and pte_val() will return u64 value consisting of those fields
concateneted.
    
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

include/asm-mips/pgtable.h

@@ -82,10 +82,11 @@ extern void paging_init(void);
 #define pmd_page(pmd)		(pfn_to_page(pmd_phys(pmd) >> PAGE_SHIFT))
 #define pmd_page_kernel(pmd)	pmd_val(pmd)
 
-#define pte_none(pte)		(!(pte_val(pte) & ~_PAGE_GLOBAL))
-#define pte_present(pte)	(pte_val(pte) & _PAGE_PRESENT)
-
 #if defined(CONFIG_64BIT_PHYS_ADDR) && defined(CONFIG_CPU_MIPS32_R1)
+
+#define pte_none(pte)		(!(((pte).pte_low | (pte).pte_high) & ~_PAGE_GLOBAL))
+#define pte_present(pte)	((pte).pte_low & _PAGE_PRESENT)
+
 static inline void set_pte(pte_t *ptep, pte_t pte)
 {
 	ptep->pte_high = pte.pte_high;
@@ -93,27 +94,35 @@ static inline void set_pte(pte_t *ptep, pte_t pte)
 	ptep->pte_low = pte.pte_low;
 	//printk("pte_high %x pte_low %x\n", ptep->pte_high, ptep->pte_low);
 
-	if (pte_val(pte) & _PAGE_GLOBAL) {
+	if (pte.pte_low & _PAGE_GLOBAL) {
 		pte_t *buddy = ptep_buddy(ptep);
 		/*
 		 * Make sure the buddy is global too (if it's !none,
 		 * it better already be global)
 		 */
-		if (pte_none(*buddy))
-			buddy->pte_low |= _PAGE_GLOBAL;
+		if (pte_none(*buddy)) {
+			buddy->pte_low  |= _PAGE_GLOBAL;
+			buddy->pte_high |= _PAGE_GLOBAL;
+		}
 	}
 }
 #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
 
 static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 {
+	pte_t null = __pte(0);
+
 	/* Preserve global status for the pair */
-	if (pte_val(*ptep_buddy(ptep)) & _PAGE_GLOBAL)
-		set_pte_at(mm, addr, ptep, __pte(_PAGE_GLOBAL));
-	else
-		set_pte_at(mm, addr, ptep, __pte(0));
+	if (ptep_buddy(ptep)->pte_low & _PAGE_GLOBAL)
+		null.pte_low = null.pte_high = _PAGE_GLOBAL;
+
+	set_pte_at(mm, addr, ptep, null);
 }
 #else
+
+#define pte_none(pte)		(!(pte_val(pte) & ~_PAGE_GLOBAL))
+#define pte_present(pte)	(pte_val(pte) & _PAGE_PRESENT)
+
 /*
  * Certain architectures need to do special things when pte's
  * within a page table are directly modified.  Thus, the following
@@ -174,75 +183,76 @@ extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
  */
 static inline int pte_user(pte_t pte)	{ BUG(); return 0; }
 #if defined(CONFIG_64BIT_PHYS_ADDR) && defined(CONFIG_CPU_MIPS32_R1)
-static inline int pte_read(pte_t pte)	{ return (pte).pte_low & _PAGE_READ; }
-static inline int pte_write(pte_t pte)	{ return (pte).pte_low & _PAGE_WRITE; }
-static inline int pte_dirty(pte_t pte)	{ return (pte).pte_low & _PAGE_MODIFIED; }
-static inline int pte_young(pte_t pte)	{ return (pte).pte_low & _PAGE_ACCESSED; }
-static inline int pte_file(pte_t pte)	{ return (pte).pte_low & _PAGE_FILE; }
+static inline int pte_read(pte_t pte)	{ return pte.pte_low & _PAGE_READ; }
+static inline int pte_write(pte_t pte)	{ return pte.pte_low & _PAGE_WRITE; }
+static inline int pte_dirty(pte_t pte)	{ return pte.pte_low & _PAGE_MODIFIED; }
+static inline int pte_young(pte_t pte)	{ return pte.pte_low & _PAGE_ACCESSED; }
+static inline int pte_file(pte_t pte)	{ return pte.pte_low & _PAGE_FILE; }
+
 static inline pte_t pte_wrprotect(pte_t pte)
 {
-	(pte).pte_low &= ~(_PAGE_WRITE | _PAGE_SILENT_WRITE);
-	(pte).pte_high &= ~_PAGE_SILENT_WRITE;
+	pte.pte_low  &= ~(_PAGE_WRITE | _PAGE_SILENT_WRITE);
+	pte.pte_high &= ~_PAGE_SILENT_WRITE;
 	return pte;
 }
 
 static inline pte_t pte_rdprotect(pte_t pte)
 {
-	(pte).pte_low &= ~(_PAGE_READ | _PAGE_SILENT_READ);
-	(pte).pte_high &= ~_PAGE_SILENT_READ;
+	pte.pte_low  &= ~(_PAGE_READ | _PAGE_SILENT_READ);
+	pte.pte_high &= ~_PAGE_SILENT_READ;
 	return pte;
 }
 
 static inline pte_t pte_mkclean(pte_t pte)
 {
-	(pte).pte_low &= ~(_PAGE_MODIFIED|_PAGE_SILENT_WRITE);
-	(pte).pte_high &= ~_PAGE_SILENT_WRITE;
+	pte.pte_low  &= ~(_PAGE_MODIFIED | _PAGE_SILENT_WRITE);
+	pte.pte_high &= ~_PAGE_SILENT_WRITE;
 	return pte;
 }
 
 static inline pte_t pte_mkold(pte_t pte)
 {
-	(pte).pte_low &= ~(_PAGE_ACCESSED|_PAGE_SILENT_READ);
-	(pte).pte_high &= ~_PAGE_SILENT_READ;
+	pte.pte_low  &= ~(_PAGE_ACCESSED | _PAGE_SILENT_READ);
+	pte.pte_high &= ~_PAGE_SILENT_READ;
 	return pte;
 }
 
 static inline pte_t pte_mkwrite(pte_t pte)
 {
-	(pte).pte_low |= _PAGE_WRITE;
-	if ((pte).pte_low & _PAGE_MODIFIED) {
-		(pte).pte_low |= _PAGE_SILENT_WRITE;
-		(pte).pte_high |= _PAGE_SILENT_WRITE;
+	pte.pte_low |= _PAGE_WRITE;
+	if (pte.pte_low & _PAGE_MODIFIED) {
+		pte.pte_low  |= _PAGE_SILENT_WRITE;
+		pte.pte_high |= _PAGE_SILENT_WRITE;
 	}
 	return pte;
 }
 
 static inline pte_t pte_mkread(pte_t pte)
 {
-	(pte).pte_low |= _PAGE_READ;
-	if ((pte).pte_low & _PAGE_ACCESSED) {
-		(pte).pte_low |= _PAGE_SILENT_READ;
-		(pte).pte_high |= _PAGE_SILENT_READ;
+	pte.pte_low |= _PAGE_READ;
+	if (pte.pte_low & _PAGE_ACCESSED) {
+		pte.pte_low  |= _PAGE_SILENT_READ;
+		pte.pte_high |= _PAGE_SILENT_READ;
 	}
 	return pte;
 }
 
 static inline pte_t pte_mkdirty(pte_t pte)
 {
-	(pte).pte_low |= _PAGE_MODIFIED;
-	if ((pte).pte_low & _PAGE_WRITE) {
-		(pte).pte_low |= _PAGE_SILENT_WRITE;
-		(pte).pte_high |= _PAGE_SILENT_WRITE;
+	pte.pte_low |= _PAGE_MODIFIED;
+	if (pte.pte_low & _PAGE_WRITE) {
+		pte.pte_low  |= _PAGE_SILENT_WRITE;
+		pte.pte_high |= _PAGE_SILENT_WRITE;
 	}
 	return pte;
 }
 
 static inline pte_t pte_mkyoung(pte_t pte)
 {
-	(pte).pte_low |= _PAGE_ACCESSED;
-	if ((pte).pte_low & _PAGE_READ)
-		(pte).pte_low |= _PAGE_SILENT_READ;
-		(pte).pte_high |= _PAGE_SILENT_READ;
+	pte.pte_low |= _PAGE_ACCESSED;
+	if (pte.pte_low & _PAGE_READ)
+		pte.pte_low  |= _PAGE_SILENT_READ;
+		pte.pte_high |= _PAGE_SILENT_READ;
 	return pte;
 }
 #else