[PATCH] s390 bits for remap-file-pages-prot.

From: Martin Schwidefsky
Date: Thu Mar 11 2004 - 14:12:05 EST

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Hi Andrew,
I tried 2.6.4-mm1 and found that it wouldn't even compile because
of the remap-file-pages-prot changes. After some bit moving in the
definition of the s390 ptes I got it to work. Please add to -mm
and send it with the remap-file-pages-prot patch when it goes
into the mainline.

blue skies,
Martin.

---
s390 memory management changes for remap-file-pages-prot patch:
- Add pgoff_prot_to_pte/pte_to_pgprot, remove pgoff_to_pte (required for
'prot' parameteter in shared-writeable mappings).
- Handle VM_FAULT_SIGSEGV from handle_mm_fault in do_exception.
- Add sys_remap_file_pages system call.
- Add MAP_INHERIT.

diffstat:
arch/s390/kernel/compat_wrapper.S | 10 +++
arch/s390/kernel/syscalls.S | 1
arch/s390/mm/fault.c | 2
include/asm-s390/mman.h | 1
include/asm-s390/pgtable.h | 122 +++++++++++++++++++++++---------------
include/asm-s390/unistd.h | 3
6 files changed, 90 insertions(+), 49 deletions(-)

diff -urN linux-2.6-orig/arch/s390/kernel/compat_wrapper.S linux-2.6/arch/s390/kernel/compat_wrapper.S
--- linux-2.6-orig/arch/s390/kernel/compat_wrapper.S Thu Mar 11 15:09:52 2004
+++ linux-2.6/arch/s390/kernel/compat_wrapper.S Thu Mar 11 15:08:19 2004
@@ -1338,3 +1338,13 @@
llgtr %r3,%r3 # struct iocb *
llgtr %r4,%r4 # struct io_event *
jg sys_io_cancel
+
+ .globl sys32_remap_file_pages_wrapper
+sys32_remap_file_pages_wrapper:
+ llgfr %r2,%r2 # unsigned long
+ llgfr %r3,%r3 # unsigned long
+ llgfr %r4,%r4 # unsigned long
+ llgfr %r5,%r5 # unsigned long
+ llgfr %r6,%r6 # unsigned long
+ jg sys_remap_file_pages
+
diff -urN linux-2.6-orig/arch/s390/kernel/syscalls.S linux-2.6/arch/s390/kernel/syscalls.S
--- linux-2.6-orig/arch/s390/kernel/syscalls.S Thu Mar 11 15:09:52 2004
+++ linux-2.6/arch/s390/kernel/syscalls.S Thu Mar 11 15:08:19 2004
@@ -273,3 +273,4 @@
SYSCALL(sys_clock_nanosleep,sys_clock_nanosleep,sys32_clock_nanosleep_wrapper)
NI_SYSCALL /* reserved for vserver */
SYSCALL(s390_fadvise64_64,sys_ni_syscall,sys32_fadvise64_64_wrapper)
+SYSCALL(sys_remap_file_pages,sys_remap_file_pages,sys32_remap_file_pages_wrapper)
diff -urN linux-2.6-orig/arch/s390/mm/fault.c linux-2.6/arch/s390/mm/fault.c
--- linux-2.6-orig/arch/s390/mm/fault.c Thu Mar 11 15:09:52 2004
+++ linux-2.6/arch/s390/mm/fault.c Thu Mar 11 15:08:19 2004
@@ -256,6 +256,8 @@
goto do_sigbus;
case VM_FAULT_OOM:
goto out_of_memory;
+ case VM_FAULT_SIGSEGV:
+ goto bad_area;
default:
BUG();
}
diff -urN linux-2.6-orig/include/asm-s390/mman.h linux-2.6/include/asm-s390/mman.h
--- linux-2.6-orig/include/asm-s390/mman.h Thu Mar 11 15:09:52 2004
+++ linux-2.6/include/asm-s390/mman.h Thu Mar 11 15:08:19 2004
@@ -30,6 +30,7 @@
#define MAP_NORESERVE 0x4000 /* don't check for reservations */
#define MAP_POPULATE 0x8000 /* populate (prefault) pagetables */
#define MAP_NONBLOCK 0x10000 /* do not block on IO */
+#define MAP_INHERIT 0x20000 /* inherit the protection bits of the underlying vma*/

#define MS_ASYNC 1 /* sync memory asynchronously */
#define MS_INVALIDATE 2 /* invalidate the caches */
diff -urN linux-2.6-orig/include/asm-s390/pgtable.h linux-2.6/include/asm-s390/pgtable.h
--- linux-2.6-orig/include/asm-s390/pgtable.h Thu Mar 11 15:09:52 2004
+++ linux-2.6/include/asm-s390/pgtable.h Thu Mar 11 15:10:13 2004
@@ -209,16 +209,41 @@
* C : changed bit
*/

-/* Hardware bits in the page table entry */
+/* Hardware bits in the page table entry. */
#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
+/* Software bits in the page table entry. */
+#define _PAGE_FILE 0x001
+#define _PAGE_PROTNONE 0x002
+
+/*
+ * We have 8 different page "types", two valid types and 6 invalid types
+ * (p = page address, o = swap offset, t = swap type, f = file offset):
+ * 0 xxxxxxxxxxxxxxxxxxx 0IP0 yyyyyy NF
+ * valid rw: 0 <--------p--------> 0000 <--0-> 00
+ * valid ro: 0 <--------p--------> 0010 <--0-> 00
+ * invalid none: 0 <--------p--------> 0100 <--0-> 10
+ * invalid empty: 0 <--------0--------> 0100 <--0-> 00
+ * invalid swap: 0 <--------o--------> 0110 <--t-> 00
+ * invalid file rw: 0 <--------f--------> 0100 <--f-> 01
+ * invalid file ro: 0 <--------f--------> 0110 <--f-> 01
+ * invaild file none: 0 <--------f--------> 0100 <--f-> 11
+ *
+ * The format for 64 bit is almost identical, there isn't a leading zero
+ * and the number of bits in the page address part of the pte is 52 bits
+ * instead of 19.
+ */
+
#define _PAGE_INVALID_EMPTY 0x400
-#define _PAGE_INVALID_NONE 0x401
#define _PAGE_INVALID_SWAP 0x600
-#define _PAGE_INVALID_FILE 0x601
+#define _PAGE_INVALID_FILE 0x401
+
+#define _PTE_IS_VALID(__pte) (!(pte_val(__pte) & _PAGE_INVALID))
+#define _PTE_IS_NONE(__pte) ((pte_val(__pte) & 0x603) == 0x402)
+#define _PTE_IS_EMPTY(__pte) ((pte_val(__pte) & 0x603) == 0x400)
+#define _PTE_IS_SWAP(__pte) ((pte_val(__pte) & 0x603) == 0x600)
+#define _PTE_IS_FILE(__pte) ((pte_val(__pte) & 0x401) == 0x401)

#ifndef __s390x__

@@ -279,13 +304,11 @@
/*
* No mapping available
*/
-#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_INVALID | _PAGE_PROTNONE)
+#define PAGE_READONLY __pgprot(_PAGE_RO)
+#define PAGE_COPY __pgprot(_PAGE_RO)
+#define PAGE_SHARED __pgprot(0)
+#define PAGE_KERNEL __pgprot(0)

/*
* The S390 can't do page protection for execute, and considers that the
@@ -293,21 +316,21 @@
* the closest we can get..
*/
/*xwr*/
-#define __P000 PAGE_NONE_PRIVATE
-#define __P001 PAGE_RO_PRIVATE
+#define __P000 PAGE_NONE
+#define __P001 PAGE_READONLY
#define __P010 PAGE_COPY
#define __P011 PAGE_COPY
-#define __P100 PAGE_RO_PRIVATE
-#define __P101 PAGE_RO_PRIVATE
+#define __P100 PAGE_READONLY
+#define __P101 PAGE_READONLY
#define __P110 PAGE_COPY
#define __P111 PAGE_COPY

-#define __S000 PAGE_NONE_SHARED
-#define __S001 PAGE_RO_SHARED
+#define __S000 PAGE_NONE
+#define __S001 PAGE_READONLY
#define __S010 PAGE_SHARED
#define __S011 PAGE_SHARED
-#define __S100 PAGE_RO_SHARED
-#define __S101 PAGE_RO_SHARED
+#define __S100 PAGE_READONLY
+#define __S101 PAGE_READONLY
#define __S110 PAGE_SHARED
#define __S111 PAGE_SHARED

@@ -373,18 +396,17 @@

extern inline int pte_none(pte_t pte)
{
- return (pte_val(pte) & _PAGE_INVALID_MASK) == _PAGE_INVALID_EMPTY;
+ return _PTE_IS_EMPTY(pte);
}

extern inline int pte_present(pte_t pte)
{
- return !(pte_val(pte) & _PAGE_INVALID) ||
- (pte_val(pte) & _PAGE_INVALID_MASK) == _PAGE_INVALID_NONE;
+ return _PTE_IS_VALID(pte) || _PTE_IS_NONE(pte);
}

extern inline int pte_file(pte_t pte)
{
- return (pte_val(pte) & _PAGE_INVALID_MASK) == _PAGE_INVALID_FILE;
+ return _PTE_IS_FILE(pte);
}

#define pte_same(a,b) (pte_val(a) == pte_val(b))
@@ -465,8 +487,8 @@

extern inline pte_t pte_wrprotect(pte_t pte)
{
- /* Do not clobber _PAGE_INVALID_NONE pages! */
- if (!(pte_val(pte) & _PAGE_INVALID))
+ /* Do not clobber PROT_NONE pages! */
+ if (!_PTE_IS_NONE(pte))
pte_val(pte) |= _PAGE_RO;
return pte;
}
@@ -719,14 +741,14 @@
* information in the lowcore.
* Bit 21 and bit 22 are the page invalid bit and the page protection
* bit. We set both to indicate a swapped page.
- * Bit 31 is used as the software page present bit. If a page is
- * swapped this obviously has to be zero.
- * This leaves the bits 1-19 and bits 24-30 to store type and offset.
- * We use the 7 bits from 24-30 for the type and the 19 bits from 1-19
+ * Bit 30 and 31 are used to distinguish the different page types. For
+ * a swapped page these bits need to be zero.
+ * This leaves the bits 1-19 and bits 24-29 to store type and offset.
+ * We use the 6 bits from 24-29 for the type and the 19 bits from 1-19
* for the offset.
- * 0| offset |0110|type |0
- * 00000000001111111111222222222233
- * 01234567890123456789012345678901
+ * 0| offset |0110| type |00|
+ * 0 0000000001111111111 2222 222222 33
+ * 0 1234567890123456789 0123 456789 01
*
* 64 bit swap entry format:
* A page-table entry has some bits we have to treat in a special way.
@@ -736,19 +758,19 @@
* information in the lowcore.
* Bit 53 and bit 54 are the page invalid bit and the page protection
* bit. We set both to indicate a swapped page.
- * Bit 63 is used as the software page present bit. If a page is
- * swapped this obviously has to be zero.
- * This leaves the bits 0-51 and bits 56-62 to store type and offset.
- * We use the 7 bits from 56-62 for the type and the 52 bits from 0-51
+ * Bit 62 and 63 are used to distinguish the different page types. For
+ * a swapped page these bits need to be zero.
+ * This leaves the bits 0-51 and bits 56-61 to store type and offset.
+ * We use the 6 bits from 56-61 for the type and the 52 bits from 0-51
* for the offset.
- * | offset |0110|type |0
- * 0000000000111111111122222222223333333333444444444455555555556666
- * 0123456789012345678901234567890123456789012345678901234567890123
+ * | offset |0110| type |00|
+ * 0000000000111111111122222222223333333333444444444455 5555 555566 66
+ * 0123456789012345678901234567890123456789012345678901 2345 678901 23
*/
extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
{
pte_t pte;
- pte_val(pte) = (type << 1) | (offset << 12) | _PAGE_INVALID_SWAP;
+ pte_val(pte) = (type << 2) | (offset << 12) | _PAGE_INVALID_SWAP;
#ifndef __s390x__
BUG_ON((pte_val(pte) & 0x80000901) != 0);
#else /* __s390x__ */
@@ -757,7 +779,7 @@
return pte;
}

-#define __swp_type(entry) (((entry).val >> 1) & 0x3f)
+#define __swp_type(entry) (((entry).val >> 2) & 0x3f)
#define __swp_offset(entry) ((entry).val >> 12)
#define __swp_entry(type,offset) ((swp_entry_t) { pte_val(mk_swap_pte((type),(offset))) })

@@ -767,17 +789,21 @@
typedef pte_t *pte_addr_t;

#ifndef __s390x__
-# define PTE_FILE_MAX_BITS 26
+# define PTE_FILE_MAX_BITS 25
#else /* __s390x__ */
-# define PTE_FILE_MAX_BITS 59
+# define PTE_FILE_MAX_BITS 58
#endif /* __s390x__ */

#define pte_to_pgoff(__pte) \
- ((((__pte).pte >> 12) << 7) + (((__pte).pte >> 1) & 0x7f))
+ ((((__pte).pte >> 12) << 6) + (((__pte).pte >> 2) & 0x3f))
+
+#define pte_to_pgprot(pte) \
+ __pgprot(pte_val(pte) & (_PAGE_RO | _PAGE_PROTNONE))

-#define pgoff_to_pte(__off) \
- ((pte_t) { ((((__off) & 0x7f) << 1) + (((__off) >> 7) << 12)) \
- | _PAGE_INVALID_FILE })
+#define pgoff_prot_to_pte(__off, __prot) \
+ ((pte_t) { _PAGE_INVALID_FILE | \
+ ((((__off) & 0x3f) << 2) + (((__off) >> 6) << 12)) | \
+ (pgprot_val(__prot) & (_PAGE_RO | _PAGE_PROTNONE)) })

#endif /* !__ASSEMBLY__ */

diff -urN linux-2.6-orig/include/asm-s390/unistd.h linux-2.6/include/asm-s390/unistd.h
--- linux-2.6-orig/include/asm-s390/unistd.h Thu Mar 11 15:09:52 2004
+++ linux-2.6/include/asm-s390/unistd.h Thu Mar 11 15:08:19 2004
@@ -260,8 +260,9 @@
* Number 263 is reserved for vserver
*/
#define __NR_fadvise64_64 264
+#define __NR_remap_file_pages 265

-#define NR_syscalls 265
+#define NR_syscalls 266

/*
* There are some system calls that are not present on 64 bit, some
-
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