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-rw-r--r--include/linux/mman.h29
-rw-r--r--mm/mmap.c5
-rw-r--r--mm/mprotect.c2
3 files changed, 32 insertions, 4 deletions
diff --git a/include/linux/mman.h b/include/linux/mman.h
index dab8892e6ff..30d1073bac3 100644
--- a/include/linux/mman.h
+++ b/include/linux/mman.h
@@ -34,6 +34,32 @@ static inline void vm_unacct_memory(long pages)
}
/*
+ * Allow architectures to handle additional protection bits
+ */
+
+#ifndef arch_calc_vm_prot_bits
+#define arch_calc_vm_prot_bits(prot) 0
+#endif
+
+#ifndef arch_vm_get_page_prot
+#define arch_vm_get_page_prot(vm_flags) __pgprot(0)
+#endif
+
+#ifndef arch_validate_prot
+/*
+ * This is called from mprotect(). PROT_GROWSDOWN and PROT_GROWSUP have
+ * already been masked out.
+ *
+ * Returns true if the prot flags are valid
+ */
+static inline int arch_validate_prot(unsigned long prot)
+{
+ return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
+}
+#define arch_validate_prot arch_validate_prot
+#endif
+
+/*
* Optimisation macro. It is equivalent to:
* (x & bit1) ? bit2 : 0
* but this version is faster.
@@ -51,7 +77,8 @@ 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 );
+ _calc_vm_trans(prot, PROT_EXEC, VM_EXEC) |
+ arch_calc_vm_prot_bits(prot);
}
/*
diff --git a/mm/mmap.c b/mm/mmap.c
index 3354fdd83d4..1d102b956fd 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -72,8 +72,9 @@ pgprot_t protection_map[16] = {
pgprot_t vm_get_page_prot(unsigned long vm_flags)
{
- return protection_map[vm_flags &
- (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
+ return __pgprot(pgprot_val(protection_map[vm_flags &
+ (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
+ pgprot_val(arch_vm_get_page_prot(vm_flags)));
}
EXPORT_SYMBOL(vm_get_page_prot);
diff --git a/mm/mprotect.c b/mm/mprotect.c
index a5bf31c2737..ecfaa5844b5 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -239,7 +239,7 @@ sys_mprotect(unsigned long start, size_t len, unsigned long prot)
end = start + len;
if (end <= start)
return -ENOMEM;
- if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM))
+ if (!arch_validate_prot(prot))
return -EINVAL;
reqprot = prot;