[S390] Cleanup in page table related code.

From: Martin Schwidefsky
Date: Tue Sep 12 2006 - 07:23:11 EST


From: Gerald Schaefer <geraldsc@xxxxxxxxxx>

[S390] Cleanup in page table related code.

Changed and simplified some page table related #defines and code.

Signed-off-by: Gerald Schaefer <geraldsc@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
---

arch/s390/mm/init.c | 36 +++++--------
include/asm-s390/pgalloc.h | 65 +++++++++++------------
include/asm-s390/pgtable.h | 124 +++++++++++++++++++++------------------------
3 files changed, 105 insertions(+), 120 deletions(-)

diff -urpN linux-2.6/arch/s390/mm/init.c linux-2.6-patched/arch/s390/mm/init.c
--- linux-2.6/arch/s390/mm/init.c 2006-09-12 10:56:59.000000000 +0200
+++ linux-2.6-patched/arch/s390/mm/init.c 2006-09-12 10:57:56.000000000 +0200
@@ -108,16 +108,23 @@ void __init paging_init(void)
unsigned long pgdir_k = (__pa(swapper_pg_dir) & PAGE_MASK) | _KERNSEG_TABLE;
static const int ssm_mask = 0x04000000L;
unsigned long ro_start_pfn, ro_end_pfn;
+ unsigned long zones_size[MAX_NR_ZONES];

ro_start_pfn = PFN_DOWN((unsigned long)&__start_rodata);
ro_end_pfn = PFN_UP((unsigned long)&__end_rodata);

+ memset(zones_size, 0, sizeof(zones_size));
+ zones_size[ZONE_DMA] = max_low_pfn;
+ free_area_init_node(0, &contig_page_data, zones_size,
+ __pa(PAGE_OFFSET) >> PAGE_SHIFT,
+ zholes_size);
+
/* unmap whole virtual address space */

pg_dir = swapper_pg_dir;

- for (i=0;i<KERNEL_PGD_PTRS;i++)
- pmd_clear((pmd_t*)pg_dir++);
+ for (i = 0; i < PTRS_PER_PGD; i++)
+ pmd_clear((pmd_t *) pg_dir++);

/*
* map whole physical memory to virtual memory (identity mapping)
@@ -131,10 +138,7 @@ void __init paging_init(void)
*/
pg_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);

- pg_dir->pgd0 = (_PAGE_TABLE | __pa(pg_table));
- pg_dir->pgd1 = (_PAGE_TABLE | (__pa(pg_table)+1024));
- pg_dir->pgd2 = (_PAGE_TABLE | (__pa(pg_table)+2048));
- pg_dir->pgd3 = (_PAGE_TABLE | (__pa(pg_table)+3072));
+ pmd_populate_kernel(&init_mm, (pmd_t *) pg_dir, pg_table);
pg_dir++;

for (tmp = 0 ; tmp < PTRS_PER_PTE ; tmp++,pg_table++) {
@@ -143,8 +147,8 @@ void __init paging_init(void)
else
pte = pfn_pte(pfn, PAGE_KERNEL);
if (pfn >= max_low_pfn)
- pte_clear(&init_mm, 0, &pte);
- set_pte(pg_table, pte);
+ pte_val(pte) = _PAGE_TYPE_EMPTY;
+ set_pte(pg_table, pte);
pfn++;
}
}
@@ -159,16 +163,6 @@ void __init paging_init(void)
: : "m" (pgdir_k), "m" (ssm_mask));

local_flush_tlb();
-
- {
- unsigned long zones_size[MAX_NR_ZONES];
-
- memset(zones_size, 0, sizeof(zones_size));
- zones_size[ZONE_DMA] = max_low_pfn;
- free_area_init_node(0, &contig_page_data, zones_size,
- __pa(PAGE_OFFSET) >> PAGE_SHIFT,
- zholes_size);
- }
return;
}

@@ -236,10 +230,8 @@ void __init paging_init(void)
pte = pfn_pte(pfn, __pgprot(_PAGE_RO));
else
pte = pfn_pte(pfn, PAGE_KERNEL);
- if (pfn >= max_low_pfn) {
- pte_clear(&init_mm, 0, &pte);
- continue;
- }
+ if (pfn >= max_low_pfn)
+ pte_val(pte) = _PAGE_TYPE_EMPTY;
set_pte(pt_dir, pte);
pfn++;
}
diff -urpN linux-2.6/include/asm-s390/pgalloc.h linux-2.6-patched/include/asm-s390/pgalloc.h
--- linux-2.6/include/asm-s390/pgalloc.h 2006-09-12 10:57:10.000000000 +0200
+++ linux-2.6-patched/include/asm-s390/pgalloc.h 2006-09-12 10:57:56.000000000 +0200
@@ -22,6 +22,16 @@
extern void diag10(unsigned long addr);

/*
+ * Page allocation orders.
+ */
+#ifndef __s390x__
+# define PGD_ALLOC_ORDER 1
+#else /* __s390x__ */
+# define PMD_ALLOC_ORDER 2
+# define PGD_ALLOC_ORDER 2
+#endif /* __s390x__ */
+
+/*
* Allocate and free page tables. The xxx_kernel() versions are
* used to allocate a kernel page table - this turns on ASN bits
* if any.
@@ -29,30 +39,23 @@ extern void diag10(unsigned long addr);

static inline pgd_t *pgd_alloc(struct mm_struct *mm)
{
- pgd_t *pgd;
+ pgd_t *pgd = (pgd_t *) __get_free_pages(GFP_KERNEL, PGD_ALLOC_ORDER);
int i;

+ if (!pgd)
+ return NULL;
+ for (i = 0; i < PTRS_PER_PGD; i++)
#ifndef __s390x__
- pgd = (pgd_t *) __get_free_pages(GFP_KERNEL,1);
- if (pgd != NULL)
- for (i = 0; i < USER_PTRS_PER_PGD; i++)
- pmd_clear(pmd_offset(pgd + i, i*PGDIR_SIZE));
-#else /* __s390x__ */
- pgd = (pgd_t *) __get_free_pages(GFP_KERNEL,2);
- if (pgd != NULL)
- for (i = 0; i < PTRS_PER_PGD; i++)
- pgd_clear(pgd + i);
-#endif /* __s390x__ */
+ pmd_clear(pmd_offset(pgd + i, i*PGDIR_SIZE));
+#else
+ pgd_clear(pgd + i);
+#endif
return pgd;
}

static inline void pgd_free(pgd_t *pgd)
{
-#ifndef __s390x__
- free_pages((unsigned long) pgd, 1);
-#else /* __s390x__ */
- free_pages((unsigned long) pgd, 2);
-#endif /* __s390x__ */
+ free_pages((unsigned long) pgd, PGD_ALLOC_ORDER);
}

#ifndef __s390x__
@@ -68,20 +71,19 @@ static inline void pgd_free(pgd_t *pgd)
#else /* __s390x__ */
static inline pmd_t * pmd_alloc_one(struct mm_struct *mm, unsigned long vmaddr)
{
- pmd_t *pmd;
- int i;
+ pmd_t *pmd = (pmd_t *) __get_free_pages(GFP_KERNEL, PMD_ALLOC_ORDER);
+ int i;

- pmd = (pmd_t *) __get_free_pages(GFP_KERNEL, 2);
- if (pmd != NULL) {
- for (i=0; i < PTRS_PER_PMD; i++)
- pmd_clear(pmd+i);
- }
+ if (!pmd)
+ return NULL;
+ for (i=0; i < PTRS_PER_PMD; i++)
+ pmd_clear(pmd + i);
return pmd;
}

static inline void pmd_free (pmd_t *pmd)
{
- free_pages((unsigned long) pmd, 2);
+ free_pages((unsigned long) pmd, PMD_ALLOC_ORDER);
}

#define __pmd_free_tlb(tlb,pmd) \
@@ -123,15 +125,14 @@ pmd_populate(struct mm_struct *mm, pmd_t
static inline pte_t *
pte_alloc_one_kernel(struct mm_struct *mm, unsigned long vmaddr)
{
- pte_t *pte;
- int i;
+ pte_t *pte = (pte_t *) __get_free_page(GFP_KERNEL|__GFP_REPEAT);
+ int i;

- pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT);
- if (pte != NULL) {
- for (i=0; i < PTRS_PER_PTE; i++) {
- pte_clear(mm, vmaddr, pte+i);
- vmaddr += PAGE_SIZE;
- }
+ if (!pte)
+ return NULL;
+ for (i=0; i < PTRS_PER_PTE; i++) {
+ pte_clear(mm, vmaddr, pte + i);
+ vmaddr += PAGE_SIZE;
}
return pte;
}
diff -urpN linux-2.6/include/asm-s390/pgtable.h linux-2.6-patched/include/asm-s390/pgtable.h
--- linux-2.6/include/asm-s390/pgtable.h 2006-09-12 10:57:10.000000000 +0200
+++ linux-2.6-patched/include/asm-s390/pgtable.h 2006-09-12 10:57:56.000000000 +0200
@@ -89,19 +89,6 @@ extern char empty_zero_page[PAGE_SIZE];
# define PTRS_PER_PGD 2048
#endif /* __s390x__ */

-/*
- * pgd entries used up by user/kernel:
- */
-#ifndef __s390x__
-# define USER_PTRS_PER_PGD 512
-# define USER_PGD_PTRS 512
-# define KERNEL_PGD_PTRS 512
-#else /* __s390x__ */
-# define USER_PTRS_PER_PGD 2048
-# define USER_PGD_PTRS 2048
-# define KERNEL_PGD_PTRS 2048
-#endif /* __s390x__ */
-
#define FIRST_USER_ADDRESS 0

#define pte_ERROR(e) \
@@ -216,12 +203,14 @@ extern char empty_zero_page[PAGE_SIZE];
#define _PAGE_RO 0x200 /* HW read-only */
#define _PAGE_INVALID 0x400 /* HW invalid */

-/* Mask and four different kinds of invalid pages. */
-#define _PAGE_INVALID_MASK 0x601
-#define _PAGE_INVALID_EMPTY 0x400
-#define _PAGE_INVALID_NONE 0x401
-#define _PAGE_INVALID_SWAP 0x600
-#define _PAGE_INVALID_FILE 0x601
+/* Mask and six different types of pages. */
+#define _PAGE_TYPE_MASK 0x601
+#define _PAGE_TYPE_EMPTY 0x400
+#define _PAGE_TYPE_NONE 0x401
+#define _PAGE_TYPE_SWAP 0x600
+#define _PAGE_TYPE_FILE 0x601
+#define _PAGE_TYPE_RO 0x200
+#define _PAGE_TYPE_RW 0x000

#ifndef __s390x__

@@ -280,15 +269,14 @@ extern char empty_zero_page[PAGE_SIZE];
#endif /* __s390x__ */

/*
- * No mapping available
+ * Page protection definitions.
*/
-#define PAGE_NONE_SHARED __pgprot(_PAGE_INVALID_NONE)
-#define PAGE_NONE_PRIVATE __pgprot(_PAGE_INVALID_NONE)
-#define PAGE_RO_SHARED __pgprot(_PAGE_RO)
-#define PAGE_RO_PRIVATE __pgprot(_PAGE_RO)
-#define PAGE_COPY __pgprot(_PAGE_RO)
-#define PAGE_SHARED __pgprot(0)
-#define PAGE_KERNEL __pgprot(0)
+#define PAGE_NONE __pgprot(_PAGE_TYPE_NONE)
+#define PAGE_RO __pgprot(_PAGE_TYPE_RO)
+#define PAGE_RW __pgprot(_PAGE_TYPE_RW)
+
+#define PAGE_KERNEL PAGE_RW
+#define PAGE_COPY PAGE_RO

/*
* The S390 can't do page protection for execute, and considers that the
@@ -296,23 +284,23 @@ extern char empty_zero_page[PAGE_SIZE];
* the closest we can get..
*/
/*xwr*/
-#define __P000 PAGE_NONE_PRIVATE
-#define __P001 PAGE_RO_PRIVATE
-#define __P010 PAGE_COPY
-#define __P011 PAGE_COPY
-#define __P100 PAGE_RO_PRIVATE
-#define __P101 PAGE_RO_PRIVATE
-#define __P110 PAGE_COPY
-#define __P111 PAGE_COPY
-
-#define __S000 PAGE_NONE_SHARED
-#define __S001 PAGE_RO_SHARED
-#define __S010 PAGE_SHARED
-#define __S011 PAGE_SHARED
-#define __S100 PAGE_RO_SHARED
-#define __S101 PAGE_RO_SHARED
-#define __S110 PAGE_SHARED
-#define __S111 PAGE_SHARED
+#define __P000 PAGE_NONE
+#define __P001 PAGE_RO
+#define __P010 PAGE_RO
+#define __P011 PAGE_RO
+#define __P100 PAGE_RO
+#define __P101 PAGE_RO
+#define __P110 PAGE_RO
+#define __P111 PAGE_RO
+
+#define __S000 PAGE_NONE
+#define __S001 PAGE_RO
+#define __S010 PAGE_RW
+#define __S011 PAGE_RW
+#define __S100 PAGE_RO
+#define __S101 PAGE_RO
+#define __S110 PAGE_RW
+#define __S111 PAGE_RW

/*
* Certain architectures need to do special things when PTEs
@@ -377,18 +365,18 @@ static inline int pmd_bad(pmd_t pmd)

static inline int pte_none(pte_t pte)
{
- return (pte_val(pte) & _PAGE_INVALID_MASK) == _PAGE_INVALID_EMPTY;
+ return (pte_val(pte) & _PAGE_TYPE_MASK) == _PAGE_TYPE_EMPTY;
}

static inline int pte_present(pte_t pte)
{
return !(pte_val(pte) & _PAGE_INVALID) ||
- (pte_val(pte) & _PAGE_INVALID_MASK) == _PAGE_INVALID_NONE;
+ (pte_val(pte) & _PAGE_TYPE_MASK) == _PAGE_TYPE_NONE;
}

static inline int pte_file(pte_t pte)
{
- return (pte_val(pte) & _PAGE_INVALID_MASK) == _PAGE_INVALID_FILE;
+ return (pte_val(pte) & _PAGE_TYPE_MASK) == _PAGE_TYPE_FILE;
}

#define pte_same(a,b) (pte_val(a) == pte_val(b))
@@ -461,7 +449,7 @@ static inline void pmd_clear(pmd_t * pmd

static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
- pte_val(*ptep) = _PAGE_INVALID_EMPTY;
+ pte_val(*ptep) = _PAGE_TYPE_EMPTY;
}

/*
@@ -477,7 +465,7 @@ static inline pte_t pte_modify(pte_t pte

static inline pte_t pte_wrprotect(pte_t pte)
{
- /* Do not clobber _PAGE_INVALID_NONE pages! */
+ /* Do not clobber _PAGE_TYPE_NONE pages! */
if (!(pte_val(pte) & _PAGE_INVALID))
pte_val(pte) |= _PAGE_RO;
return pte;
@@ -556,26 +544,30 @@ static inline pte_t ptep_get_and_clear(s
return pte;
}

-static inline pte_t
-ptep_clear_flush(struct vm_area_struct *vma,
- unsigned long address, pte_t *ptep)
+static inline void __ptep_ipte(unsigned long address, pte_t *ptep)
{
- pte_t pte = *ptep;
+ if (!(pte_val(*ptep) & _PAGE_INVALID)) {
#ifndef __s390x__
- if (!(pte_val(pte) & _PAGE_INVALID)) {
/* S390 has 1mb segments, we are emulating 4MB segments */
pte_t *pto = (pte_t *) (((unsigned long) ptep) & 0x7ffffc00);
- __asm__ __volatile__ ("ipte %2,%3"
- : "=m" (*ptep) : "m" (*ptep),
- "a" (pto), "a" (address) );
+#else
+ /* ipte in zarch mode can do the math */
+ pte_t *pto = ptep;
+#endif
+ asm volatile ("ipte %2,%3"
+ : "=m" (*ptep) : "m" (*ptep),
+ "a" (pto), "a" (address) );
}
-#else /* __s390x__ */
- if (!(pte_val(pte) & _PAGE_INVALID))
- __asm__ __volatile__ ("ipte %2,%3"
- : "=m" (*ptep) : "m" (*ptep),
- "a" (ptep), "a" (address) );
-#endif /* __s390x__ */
- pte_val(*ptep) = _PAGE_INVALID_EMPTY;
+ pte_val(*ptep) = _PAGE_TYPE_EMPTY;
+}
+
+static inline pte_t
+ptep_clear_flush(struct vm_area_struct *vma,
+ unsigned long address, pte_t *ptep)
+{
+ pte_t pte = *ptep;
+
+ __ptep_ipte(address, ptep);
return pte;
}

@@ -755,7 +747,7 @@ static inline pte_t mk_swap_pte(unsigned
{
pte_t pte;
offset &= __SWP_OFFSET_MASK;
- pte_val(pte) = _PAGE_INVALID_SWAP | ((type & 0x1f) << 2) |
+ pte_val(pte) = _PAGE_TYPE_SWAP | ((type & 0x1f) << 2) |
((offset & 1UL) << 7) | ((offset & ~1UL) << 11);
return pte;
}
@@ -778,7 +770,7 @@ static inline pte_t mk_swap_pte(unsigned

#define pgoff_to_pte(__off) \
((pte_t) { ((((__off) & 0x7f) << 1) + (((__off) >> 7) << 12)) \
- | _PAGE_INVALID_FILE })
+ | _PAGE_TYPE_FILE })

#endif /* !__ASSEMBLY__ */

-
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