arch/tile: allow building Linux with transparent huge pages enabled

The change adds some infrastructure for managing tile pmd's more generally, using pte_pmd() and pmd_pte() methods to translate pmd values to and from ptes, since on TILEPro a pmd is really just a nested structure holding a pgd (aka pte). Several existing pmd methods are moved into this framework, and a whole raft of additional pmd accessors are defined that are used by the transparent hugepage framework. The tile PTE now has a "client2" bit. The bit is used to indicate a transparent huge page is in the process of being split into subpages. This change also fixes a generic bug where the return value of the generic pmdp_splitting_flush() was incorrect. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

arch/tile: allow building Linux with transparent huge pages enabled
The change adds some infrastructure for managing tile pmd's more generally, using pte_pmd() and pmd_pte() methods to translate pmd values to and from ptes, since on TILEPro a pmd is really just a nested structure holding a pgd (aka pte). Several existing pmd methods are moved into this framework, and a whole raft of additional pmd accessors are defined that are used by the transparent hugepage framework. The tile PTE now has a "client2" bit. The bit is used to indicate a transparent huge page is in the process of being split into subpages. This change also fixes a generic bug where the return value of the generic pmdp_splitting_flush() was incorrect. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Chris Metcalf
1 parent 51007004f4
Showing 6 changed files with 111 additions and 53 deletions Side-by-side Diff
arch/tile/include/asm/pgtable.h
arch/tile/include/asm/pgtable_32.h
arch/tile/include/asm/pgtable_64.h
arch/tile/include/hv/hypervisor.h
include/asm-generic/pgtable.h
mm/pgtable-generic.c
@@ -187,6 +187,7 @@
  * Undefined behaviour if not..
  */
 #define pte_present hv_pte_get_present
+#define pte_mknotpresent hv_pte_clear_present
 #define pte_user hv_pte_get_user
 #define pte_read hv_pte_get_readable
 #define pte_dirty hv_pte_get_dirty
@@ -312,7 +313,7 @@
  */
 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 {
-	return pfn_pte(hv_pte_get_pfn(pte), newprot);
+	return pfn_pte(pte_pfn(pte), newprot);
 }
  
 /*
@@ -410,6 +411,46 @@
 	return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1);
 }
  
+#define __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
+static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
+					    unsigned long address,
+					    pmd_t *pmdp)
+{
+	return ptep_test_and_clear_young(vma, address, pmdp_ptep(pmdp));
+}
+
+#define __HAVE_ARCH_PMDP_SET_WRPROTECT
+static inline void pmdp_set_wrprotect(struct mm_struct *mm,
+				      unsigned long address, pmd_t *pmdp)
+{
+	ptep_set_wrprotect(mm, address, pmdp_ptep(pmdp));
+}
+
+
+#define __HAVE_ARCH_PMDP_GET_AND_CLEAR
+static inline pmd_t pmdp_get_and_clear(struct mm_struct *mm,
+				       unsigned long address,
+				       pmd_t *pmdp)
+{
+	return pte_pmd(ptep_get_and_clear(mm, address, pmdp_ptep(pmdp)));
+}
+
+static inline void __set_pmd(pmd_t *pmdp, pmd_t pmdval)
+{
+	set_pte(pmdp_ptep(pmdp), pmd_pte(pmdval));
+}
+
+#define set_pmd_at(mm, addr, pmdp, pmdval) __set_pmd(pmdp, pmdval)
+
+/* Create a pmd from a PTFN. */
+static inline pmd_t ptfn_pmd(unsigned long ptfn, pgprot_t prot)
+{
+	return pte_pmd(hv_pte_set_ptfn(prot, ptfn));
+}
+
+/* Return the page-table frame number (ptfn) that a pmd_t points at. */
+#define pmd_ptfn(pmd) hv_pte_get_ptfn(pmd_pte(pmd))
+
 /*
  * A given kernel pmd_t maps to a specific virtual address (either a
  * kernel huge page or a kernel pte_t table).  Since kernel pte_t
@@ -432,6 +473,47 @@
  */
 #define pmd_page(pmd) pfn_to_page(HV_PTFN_TO_PFN(pmd_ptfn(pmd)))
  
+static inline void pmd_clear(pmd_t *pmdp)
+{
+	__pte_clear(pmdp_ptep(pmdp));
+}
+
+#define pmd_mknotpresent(pmd)	pte_pmd(pte_mknotpresent(pmd_pte(pmd)))
+#define pmd_young(pmd)		pte_young(pmd_pte(pmd))
+#define pmd_mkyoung(pmd)	pte_pmd(pte_mkyoung(pmd_pte(pmd)))
+#define pmd_mkold(pmd)		pte_pmd(pte_mkold(pmd_pte(pmd)))
+#define pmd_mkwrite(pmd)	pte_pmd(pte_mkwrite(pmd_pte(pmd)))
+#define pmd_write(pmd)		pte_write(pmd_pte(pmd))
+#define pmd_wrprotect(pmd)	pte_pmd(pte_wrprotect(pmd_pte(pmd)))
+#define pmd_mkdirty(pmd)	pte_pmd(pte_mkdirty(pmd_pte(pmd)))
+#define pmd_huge_page(pmd)	pte_huge(pmd_pte(pmd))
+#define pmd_mkhuge(pmd)		pte_pmd(pte_mkhuge(pmd_pte(pmd)))
+#define __HAVE_ARCH_PMD_WRITE
+
+#define pfn_pmd(pfn, pgprot)	pte_pmd(pfn_pte((pfn), (pgprot)))
+#define pmd_pfn(pmd)		pte_pfn(pmd_pte(pmd))
+#define mk_pmd(page, pgprot)	pfn_pmd(page_to_pfn(page), (pgprot))
+
+static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
+{
+	return pfn_pmd(pmd_pfn(pmd), newprot);
+}
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#define has_transparent_hugepage() 1
+#define pmd_trans_huge pmd_huge_page
+
+static inline pmd_t pmd_mksplitting(pmd_t pmd)
+{
+	return pte_pmd(hv_pte_set_client2(pmd_pte(pmd)));
+}
+
+static inline int pmd_trans_splitting(pmd_t pmd)
+{
+	return hv_pte_get_client2(pmd_pte(pmd));
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
 /*
  * The pte page can be thought of an array like this: pte_t[PTRS_PER_PTE]
  *
@@ -446,11 +528,6 @@
 static inline pte_t *pte_offset_kernel(pmd_t *pmd, unsigned long address)
 {
        return (pte_t *)pmd_page_vaddr(*pmd) + pte_index(address);
-}
-
-static inline int pmd_huge_page(pmd_t pmd)
-{
-	return pmd_val(pmd) & _PAGE_HUGE_PAGE;
 }
  
 #include <asm-generic/pgtable.h>
@@ -111,24 +111,14 @@
 	return pte;
 }
  
-static inline void __set_pmd(pmd_t *pmdp, pmd_t pmdval)
-{
-	set_pte(&pmdp->pud.pgd, pmdval.pud.pgd);
-}
-
-/* Create a pmd from a PTFN. */
-static inline pmd_t ptfn_pmd(unsigned long ptfn, pgprot_t prot)
-{
-	return (pmd_t){ { hv_pte_set_ptfn(prot, ptfn) } };
-}
-
-/* Return the page-table frame number (ptfn) that a pmd_t points at. */
-#define pmd_ptfn(pmd) hv_pte_get_ptfn((pmd).pud.pgd)
-
-static inline void pmd_clear(pmd_t *pmdp)
-{
-	__pte_clear(&pmdp->pud.pgd);
-}
+/*
+ * pmds are wrappers around pgds, which are the same as ptes.
+ * It's often convenient to "cast" back and forth and use the pte methods,
+ * which are the methods supplied by the hypervisor.
+ */
+#define pmd_pte(pmd) ((pmd).pud.pgd)
+#define pmdp_ptep(pmdp) (&(pmdp)->pud.pgd)
+#define pte_pmd(pte) ((pmd_t){ { (pte) } })
  
 #endif /* __ASSEMBLY__ */
  
@@ -108,28 +108,6 @@
 #define pmd_offset(pud, address) \
 	((pmd_t *)pud_page_vaddr(*(pud)) + pmd_index(address))
  
-static inline void __set_pmd(pmd_t *pmdp, pmd_t pmdval)
-{
-	set_pte(pmdp, pmdval);
-}
-
-/* Create a pmd from a PTFN and pgprot. */
-static inline pmd_t ptfn_pmd(unsigned long ptfn, pgprot_t prot)
-{
-	return hv_pte_set_ptfn(prot, ptfn);
-}
-
-/* Return the page-table frame number (ptfn) that a pmd_t points at. */
-static inline unsigned long pmd_ptfn(pmd_t pmd)
-{
-	return hv_pte_get_ptfn(pmd);
-}
-
-static inline void pmd_clear(pmd_t *pmdp)
-{
-	__pte_clear(pmdp);
-}
-
 /* Normalize an address to having the correct high bits set. */
 #define pgd_addr_normalize pgd_addr_normalize
 static inline unsigned long pgd_addr_normalize(unsigned long addr)
@@ -169,6 +147,13 @@
 {
 	return hv_pte(__insn_exch(&ptep->val, 0UL));
 }
+
+/*
+ * pmds are the same as pgds and ptes, so converting is a no-op.
+ */
+#define pmd_pte(pmd) (pmd)
+#define pmdp_ptep(pmdp) (pmdp)
+#define pte_pmd(pte) (pte)
  
 #endif /* __ASSEMBLY__ */
  
@@ -1855,8 +1855,7 @@
                                               future use. */
 #define HV_PTE_INDEX_MODE            16  /**< Page mode; see HV_PTE_MODE_xxx */
 #define HV_PTE_MODE_BITS              3  /**< Number of bits in mode */
-                                         /*   Bit 19 is reserved for
-                                              future use. */
+#define HV_PTE_INDEX_CLIENT2         19  /**< Page client state 2 */
 #define HV_PTE_INDEX_LOTAR           20  /**< Page's LOTAR; must be high bits
                                               of word */
 #define HV_PTE_LOTAR_BITS            12  /**< Number of bits in a LOTAR */
@@ -2046,6 +2045,13 @@
  */
 #define HV_PTE_CLIENT1               (__HV_PTE_ONE << HV_PTE_INDEX_CLIENT1)
  
+/** Client-private bit in PTE.
+ *
+ * This bit is guaranteed not to be inspected or modified by the
+ * hypervisor.
+ */
+#define HV_PTE_CLIENT2               (__HV_PTE_ONE << HV_PTE_INDEX_CLIENT2)
+
 /** Non-coherent (NC) bit in PTE.
  *
  * If this bit is set, the mapping that is set up will be non-coherent
@@ -2180,6 +2186,7 @@
 _HV_BIT(page,            PAGE)
 _HV_BIT(client0,         CLIENT0)
 _HV_BIT(client1,         CLIENT1)
+_HV_BIT(client2,         CLIENT2)
 _HV_BIT(migrating,       MIGRATING)
 _HV_BIT(nc,              NC)
 _HV_BIT(readable,        READABLE)
@@ -158,9 +158,8 @@
 #endif
  
 #ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH
-extern pmd_t pmdp_splitting_flush(struct vm_area_struct *vma,
-				  unsigned long address,
-				  pmd_t *pmdp);
+extern void pmdp_splitting_flush(struct vm_area_struct *vma,
+				 unsigned long address, pmd_t *pmdp);
 #endif
  
 #ifndef __HAVE_ARCH_PTE_SAME
@@ -109,8 +109,8 @@
  
 #ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-pmd_t pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
-			   pmd_t *pmdp)
+void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
+			  pmd_t *pmdp)
 {
 	pmd_t pmd = pmd_mksplitting(*pmdp);
 	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
...	...	@@ -187,6 +187,7 @@
187	187	* Undefined behaviour if not..
188	188	*/
189	189	#define pte_present hv_pte_get_present
	190	+#define pte_mknotpresent hv_pte_clear_present
190	191	#define pte_user hv_pte_get_user
191	192	#define pte_read hv_pte_get_readable
192	193	#define pte_dirty hv_pte_get_dirty
...	...	@@ -312,7 +313,7 @@
312	313	*/
313	314	static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
314	315	{
315		- return pfn_pte(hv_pte_get_pfn(pte), newprot);
	316	+ return pfn_pte(pte_pfn(pte), newprot);
316	317	}
317	318
318	319	/*
...	...	@@ -410,6 +411,46 @@
410	411	return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1);
411	412	}
412	413
	414	+#define __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
	415	+static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
	416	+ unsigned long address,
	417	+ pmd_t *pmdp)
	418	+{
	419	+ return ptep_test_and_clear_young(vma, address, pmdp_ptep(pmdp));
	420	+}
	421	+
	422	+#define __HAVE_ARCH_PMDP_SET_WRPROTECT
	423	+static inline void pmdp_set_wrprotect(struct mm_struct *mm,
	424	+ unsigned long address, pmd_t *pmdp)
	425	+{
	426	+ ptep_set_wrprotect(mm, address, pmdp_ptep(pmdp));
	427	+}
	428	+
	429	+
	430	+#define __HAVE_ARCH_PMDP_GET_AND_CLEAR
	431	+static inline pmd_t pmdp_get_and_clear(struct mm_struct *mm,
	432	+ unsigned long address,
	433	+ pmd_t *pmdp)
	434	+{
	435	+ return pte_pmd(ptep_get_and_clear(mm, address, pmdp_ptep(pmdp)));
	436	+}
	437	+
	438	+static inline void __set_pmd(pmd_t *pmdp, pmd_t pmdval)
	439	+{
	440	+ set_pte(pmdp_ptep(pmdp), pmd_pte(pmdval));
	441	+}
	442	+
	443	+#define set_pmd_at(mm, addr, pmdp, pmdval) __set_pmd(pmdp, pmdval)
	444	+
	445	+/* Create a pmd from a PTFN. */
	446	+static inline pmd_t ptfn_pmd(unsigned long ptfn, pgprot_t prot)
	447	+{
	448	+ return pte_pmd(hv_pte_set_ptfn(prot, ptfn));
	449	+}
	450	+
	451	+/* Return the page-table frame number (ptfn) that a pmd_t points at. */
	452	+#define pmd_ptfn(pmd) hv_pte_get_ptfn(pmd_pte(pmd))
	453	+
413	454	/*
414	455	* A given kernel pmd_t maps to a specific virtual address (either a
415	456	* kernel huge page or a kernel pte_t table). Since kernel pte_t
...	...	@@ -432,6 +473,47 @@
432	473	*/
433	474	#define pmd_page(pmd) pfn_to_page(HV_PTFN_TO_PFN(pmd_ptfn(pmd)))
434	475
	476	+static inline void pmd_clear(pmd_t *pmdp)
	477	+{
	478	+ __pte_clear(pmdp_ptep(pmdp));
	479	+}
	480	+
	481	+#define pmd_mknotpresent(pmd) pte_pmd(pte_mknotpresent(pmd_pte(pmd)))
	482	+#define pmd_young(pmd) pte_young(pmd_pte(pmd))
	483	+#define pmd_mkyoung(pmd) pte_pmd(pte_mkyoung(pmd_pte(pmd)))
	484	+#define pmd_mkold(pmd) pte_pmd(pte_mkold(pmd_pte(pmd)))
	485	+#define pmd_mkwrite(pmd) pte_pmd(pte_mkwrite(pmd_pte(pmd)))
	486	+#define pmd_write(pmd) pte_write(pmd_pte(pmd))
	487	+#define pmd_wrprotect(pmd) pte_pmd(pte_wrprotect(pmd_pte(pmd)))
	488	+#define pmd_mkdirty(pmd) pte_pmd(pte_mkdirty(pmd_pte(pmd)))
	489	+#define pmd_huge_page(pmd) pte_huge(pmd_pte(pmd))
	490	+#define pmd_mkhuge(pmd) pte_pmd(pte_mkhuge(pmd_pte(pmd)))
	491	+#define __HAVE_ARCH_PMD_WRITE
	492	+
	493	+#define pfn_pmd(pfn, pgprot) pte_pmd(pfn_pte((pfn), (pgprot)))
	494	+#define pmd_pfn(pmd) pte_pfn(pmd_pte(pmd))
	495	+#define mk_pmd(page, pgprot) pfn_pmd(page_to_pfn(page), (pgprot))
	496	+
	497	+static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
	498	+{
	499	+ return pfn_pmd(pmd_pfn(pmd), newprot);
	500	+}
	501	+
	502	+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	503	+#define has_transparent_hugepage() 1
	504	+#define pmd_trans_huge pmd_huge_page
	505	+
	506	+static inline pmd_t pmd_mksplitting(pmd_t pmd)
	507	+{
	508	+ return pte_pmd(hv_pte_set_client2(pmd_pte(pmd)));
	509	+}
	510	+
	511	+static inline int pmd_trans_splitting(pmd_t pmd)
	512	+{
	513	+ return hv_pte_get_client2(pmd_pte(pmd));
	514	+}
	515	+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
	516	+
435	517	/*
436	518	* The pte page can be thought of an array like this: pte_t[PTRS_PER_PTE]
437	519	*
...	...	@@ -446,11 +528,6 @@
446	528	static inline pte_t pte_offset_kernel(pmd_t pmd, unsigned long address)
447	529	{
448	530	return (pte_t )pmd_page_vaddr(pmd) + pte_index(address);
449		-}
450		-
451		-static inline int pmd_huge_page(pmd_t pmd)
452		-{
453		- return pmd_val(pmd) & _PAGE_HUGE_PAGE;
454	531	}
455	532
456	533	#include <asm-generic/pgtable.h>
...	...	@@ -111,24 +111,14 @@
111	111	return pte;
112	112	}
113	113
114		-static inline void __set_pmd(pmd_t *pmdp, pmd_t pmdval)
115		-{
116		- set_pte(&pmdp->pud.pgd, pmdval.pud.pgd);
117		-}
118		-
119		-/* Create a pmd from a PTFN. */
120		-static inline pmd_t ptfn_pmd(unsigned long ptfn, pgprot_t prot)
121		-{
122		- return (pmd_t){ { hv_pte_set_ptfn(prot, ptfn) } };
123		-}
124		-
125		-/* Return the page-table frame number (ptfn) that a pmd_t points at. */
126		-#define pmd_ptfn(pmd) hv_pte_get_ptfn((pmd).pud.pgd)
127		-
128		-static inline void pmd_clear(pmd_t *pmdp)
129		-{
130		- __pte_clear(&pmdp->pud.pgd);
131		-}
	114	+/*
	115	+ * pmds are wrappers around pgds, which are the same as ptes.
	116	+ * It's often convenient to "cast" back and forth and use the pte methods,
	117	+ * which are the methods supplied by the hypervisor.
	118	+ */
	119	+#define pmd_pte(pmd) ((pmd).pud.pgd)
	120	+#define pmdp_ptep(pmdp) (&(pmdp)->pud.pgd)
	121	+#define pte_pmd(pte) ((pmd_t){ { (pte) } })
132	122
133	123	#endif /* __ASSEMBLY__ */
134	124
...	...	@@ -108,28 +108,6 @@
108	108	#define pmd_offset(pud, address) \
109	109	((pmd_t )pud_page_vaddr((pud)) + pmd_index(address))
110	110
111		-static inline void __set_pmd(pmd_t *pmdp, pmd_t pmdval)
112		-{
113		- set_pte(pmdp, pmdval);
114		-}
115		-
116		-/* Create a pmd from a PTFN and pgprot. */
117		-static inline pmd_t ptfn_pmd(unsigned long ptfn, pgprot_t prot)
118		-{
119		- return hv_pte_set_ptfn(prot, ptfn);
120		-}
121		-
122		-/* Return the page-table frame number (ptfn) that a pmd_t points at. */
123		-static inline unsigned long pmd_ptfn(pmd_t pmd)
124		-{
125		- return hv_pte_get_ptfn(pmd);
126		-}
127		-
128		-static inline void pmd_clear(pmd_t *pmdp)
129		-{
130		- __pte_clear(pmdp);
131		-}
132		-
133	111	/* Normalize an address to having the correct high bits set. */
134	112	#define pgd_addr_normalize pgd_addr_normalize
135	113	static inline unsigned long pgd_addr_normalize(unsigned long addr)
...	...	@@ -169,6 +147,13 @@
169	147	{
170	148	return hv_pte(__insn_exch(&ptep->val, 0UL));
171	149	}
	150	+
	151	+/*
	152	+ * pmds are the same as pgds and ptes, so converting is a no-op.
	153	+ */
	154	+#define pmd_pte(pmd) (pmd)
	155	+#define pmdp_ptep(pmdp) (pmdp)
	156	+#define pte_pmd(pte) (pte)
172	157
173	158	#endif /* __ASSEMBLY__ */
174	159
...	...	@@ -1855,8 +1855,7 @@
1855	1855	future use. */
1856	1856	#define HV_PTE_INDEX_MODE 16 /*< Page mode; see HV_PTE_MODE_xxx /
1857	1857	#define HV_PTE_MODE_BITS 3 /*< Number of bits in mode /
1858		- /* Bit 19 is reserved for
1859		- future use. */
	1858	+#define HV_PTE_INDEX_CLIENT2 19 /*< Page client state 2 /
1860	1859	#define HV_PTE_INDEX_LOTAR 20 /**< Page's LOTAR; must be high bits
1861	1860	of word */
1862	1861	#define HV_PTE_LOTAR_BITS 12 /*< Number of bits in a LOTAR /
...	...	@@ -2046,6 +2045,13 @@
2046	2045	*/
2047	2046	#define HV_PTE_CLIENT1 (__HV_PTE_ONE << HV_PTE_INDEX_CLIENT1)
2048	2047
	2048	+/** Client-private bit in PTE.
	2049	+ *
	2050	+ * This bit is guaranteed not to be inspected or modified by the
	2051	+ * hypervisor.
	2052	+ */
	2053	+#define HV_PTE_CLIENT2 (__HV_PTE_ONE << HV_PTE_INDEX_CLIENT2)
	2054	+
2049	2055	/** Non-coherent (NC) bit in PTE.
2050	2056	*
2051	2057	* If this bit is set, the mapping that is set up will be non-coherent
...	...	@@ -2180,6 +2186,7 @@
2180	2186	_HV_BIT(page, PAGE)
2181	2187	_HV_BIT(client0, CLIENT0)
2182	2188	_HV_BIT(client1, CLIENT1)
	2189	+_HV_BIT(client2, CLIENT2)
2183	2190	_HV_BIT(migrating, MIGRATING)
2184	2191	_HV_BIT(nc, NC)
2185	2192	_HV_BIT(readable, READABLE)
...	...	@@ -158,9 +158,8 @@
158	158	#endif
159	159
160	160	#ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH
161		-extern pmd_t pmdp_splitting_flush(struct vm_area_struct *vma,
162		- unsigned long address,
163		- pmd_t *pmdp);
	161	+extern void pmdp_splitting_flush(struct vm_area_struct *vma,
	162	+ unsigned long address, pmd_t *pmdp);
164	163	#endif
165	164
166	165	#ifndef __HAVE_ARCH_PTE_SAME
...	...	@@ -109,8 +109,8 @@
109	109
110	110	#ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH
111	111	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
112		-pmd_t pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
113		- pmd_t *pmdp)
	112	+void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
	113	+ pmd_t *pmdp)
114	114	{
115	115	pmd_t pmd = pmd_mksplitting(*pmdp);
116	116	VM_BUG_ON(address & ~HPAGE_PMD_MASK);