diff options
| author | Dave Kleikamp <shaggy@linux.vnet.ibm.com> | 2008-07-08 00:28:51 +1000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2008-07-09 16:30:45 +1000 |
| commit | b845f313d78e4e259ec449909e3bbadf77b53a6d (patch) | |
| tree | 03239e77dbc43f627ce112963736c8b4c53117e6 | |
| parent | e5093ff05d36c64e8f36a9ddb26358256dc133ea (diff) | |
mm: Allow architectures to define additional protection bits
This patch allows architectures to define functions to deal with
additional protections bits for mmap() and mprotect().
arch_calc_vm_prot_bits() maps additonal protection bits to vm_flags
arch_vm_get_page_prot() maps additional vm_flags to the vma's vm_page_prot
arch_validate_prot() checks for valid values of the protection bits
Note: vm_get_page_prot() is now pretty ugly, but the generated code
should be identical for architectures that don't define additional
protection bits.
Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
| -rw-r--r-- | include/linux/mman.h | 29 | ||||
| -rw-r--r-- | mm/mmap.c | 5 | ||||
| -rw-r--r-- | mm/mprotect.c | 2 |
3 files changed, 32 insertions, 4 deletions
diff --git a/include/linux/mman.h b/include/linux/mman.h index dab8892e6ff1..30d1073bac3b 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 3354fdd83d4b..1d102b956fd8 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 a5bf31c27375..ecfaa5844b5f 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; |