Here's a patch to linux kernel to enable fork() support for
infiniband uverbs (userspace i/o initiator).
Please Cc me with comments.
---
This patch adds PROT_DONTCOPY to mmap and mprotect, to set VM_DONTCOPY on vma.
This is needed for infiniband userspace i/o, where we need to protect against
- the child process accessing the parent hardware page
- the parent registered address (on which the driver did get_user_pages)
getting remapped to another page by COW
One can imagine other uses, e.g. combined with mlock for real-time or security.
Signed-off-by: Michael S. Tsirkin <[email protected]>
Index: linux-2.6.12.2/include/asm-ppc64/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-ppc64/mman.h
+++ linux-2.6.12.2/include/asm-ppc64/mman.h
@@ -15,6 +15,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-cris/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-cris/mman.h
+++ linux-2.6.12.2/include/asm-cris/mman.h
@@ -10,6 +10,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-arm26/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-arm26/mman.h
+++ linux-2.6.12.2/include/asm-arm26/mman.h
@@ -8,6 +8,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-alpha/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-alpha/mman.h
+++ linux-2.6.12.2/include/asm-alpha/mman.h
@@ -8,6 +8,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-m68k/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-m68k/mman.h
+++ linux-2.6.12.2/include/asm-m68k/mman.h
@@ -8,6 +8,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-mips/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-mips/mman.h
+++ linux-2.6.12.2/include/asm-mips/mman.h
@@ -22,6 +22,7 @@
#define PROT_SEM 0x10 /* page may be used for atomic ops */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
/*
* Flags for mmap
Index: linux-2.6.12.2/include/asm-sparc64/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-sparc64/mman.h
+++ linux-2.6.12.2/include/asm-sparc64/mman.h
@@ -11,6 +11,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-v850/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-v850/mman.h
+++ linux-2.6.12.2/include/asm-v850/mman.h
@@ -7,6 +7,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-s390/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-s390/mman.h
+++ linux-2.6.12.2/include/asm-s390/mman.h
@@ -16,6 +16,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-parisc/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-parisc/mman.h
+++ linux-2.6.12.2/include/asm-parisc/mman.h
@@ -8,6 +8,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-ppc/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-ppc/mman.h
+++ linux-2.6.12.2/include/asm-ppc/mman.h
@@ -8,6 +8,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-i386/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-i386/mman.h
+++ linux-2.6.12.2/include/asm-i386/mman.h
@@ -8,6 +8,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-sh/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-sh/mman.h
+++ linux-2.6.12.2/include/asm-sh/mman.h
@@ -8,6 +8,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-x86_64/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-x86_64/mman.h
+++ linux-2.6.12.2/include/asm-x86_64/mman.h
@@ -8,6 +8,7 @@
#define PROT_SEM 0x8
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-ia64/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-ia64/mman.h
+++ linux-2.6.12.2/include/asm-ia64/mman.h
@@ -15,6 +15,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-sparc/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-sparc/mman.h
+++ linux-2.6.12.2/include/asm-sparc/mman.h
@@ -11,6 +11,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-m32r/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-m32r/mman.h
+++ linux-2.6.12.2/include/asm-m32r/mman.h
@@ -10,6 +10,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-frv/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-frv/mman.h
+++ linux-2.6.12.2/include/asm-frv/mman.h
@@ -8,6 +8,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/linux/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/linux/mman.h
+++ linux-2.6.12.2/include/linux/mman.h
@@ -47,9 +47,10 @@ static inline void vm_unacct_memory(long
static inline unsigned long
calc_vm_prot_bits(unsigned long prot)
{
- return _calc_vm_trans(prot, PROT_READ, VM_READ ) |
- _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
- _calc_vm_trans(prot, PROT_EXEC, VM_EXEC );
+ return _calc_vm_trans(prot, PROT_READ, VM_READ ) |
+ _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
+ _calc_vm_trans(prot, PROT_EXEC, VM_EXEC ) |
+ _calc_vm_trans(prot, PROT_DONTCOPY, VM_DONTCOPY );
}
/*
Index: linux-2.6.12.2/include/asm-h8300/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-h8300/mman.h
+++ linux-2.6.12.2/include/asm-h8300/mman.h
@@ -8,6 +8,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/include/asm-arm/mman.h
===================================================================
--- linux-2.6.12.2.orig/include/asm-arm/mman.h
+++ linux-2.6.12.2/include/asm-arm/mman.h
@@ -8,6 +8,7 @@
#define PROT_NONE 0x0 /* page can not be accessed */
#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
+#define PROT_DONTCOPY 0x04000000 /* dont copy to child on fork */
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
Index: linux-2.6.12.2/mm/mprotect.c
===================================================================
--- linux-2.6.12.2.orig/mm/mprotect.c
+++ linux-2.6.12.2/mm/mprotect.c
@@ -196,7 +196,7 @@ sys_mprotect(unsigned long start, size_t
end = start + len;
if (end <= start)
return -ENOMEM;
- if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM))
+ if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM | PROT_DONTCOPY))
return -EINVAL;
reqprot = prot;
@@ -246,7 +246,7 @@ sys_mprotect(unsigned long start, size_t
goto out;
}
- newflags = vm_flags | (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));
+ newflags = vm_flags | (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC | VM_DONTCOPY));
if ((newflags & ~(newflags >> 4)) & 0xf) {
error = -EACCES;
Index: linux-2.6.12.2/mm/mmap.c
===================================================================
--- linux-2.6.12.2.orig/mm/mmap.c
+++ linux-2.6.12.2/mm/mmap.c
@@ -792,8 +792,8 @@ struct anon_vma *find_mergeable_anon_vma
* Neither mlock nor madvise tries to remerge at present,
* so leave their flags as obstructing a merge.
*/
- vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
- vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
+ vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC|VM_DONTCOPY);
+ vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_DONTCOPY);
if (near->anon_vma && vma->vm_end == near->vm_start &&
mpol_equal(vma_policy(vma), vma_policy(near)) &&
@@ -814,8 +814,8 @@ try_prev:
if (!near)
goto none;
- vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
- vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
+ vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC|VM_DONTCOPY);
+ vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_DONTCOPY);
if (near->anon_vma && near->vm_end == vma->vm_start &&
mpol_equal(vma_policy(near), vma_policy(vma)) &&
--
MST
-
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