kernel-ark/include/linux/mman.h
Alan Cox 80119ef5c8 mm: fix atomic_t overflow in vm
The atomic_t type is 32bit but a 64bit system can have more than 2^32
pages of virtual address space available.  Without this we overflow on
ludicrously large mappings

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-24 09:56:09 -07:00

70 lines
1.6 KiB
C

#ifndef _LINUX_MMAN_H
#define _LINUX_MMAN_H
#include <asm/mman.h>
#define MREMAP_MAYMOVE 1
#define MREMAP_FIXED 2
#define OVERCOMMIT_GUESS 0
#define OVERCOMMIT_ALWAYS 1
#define OVERCOMMIT_NEVER 2
#ifdef __KERNEL__
#include <linux/mm.h>
#include <asm/atomic.h>
extern int sysctl_overcommit_memory;
extern int sysctl_overcommit_ratio;
extern atomic_long_t vm_committed_space;
#ifdef CONFIG_SMP
extern void vm_acct_memory(long pages);
#else
static inline void vm_acct_memory(long pages)
{
atomic_long_add(pages, &vm_committed_space);
}
#endif
static inline void vm_unacct_memory(long pages)
{
vm_acct_memory(-pages);
}
/*
* Optimisation macro. It is equivalent to:
* (x & bit1) ? bit2 : 0
* but this version is faster.
* ("bit1" and "bit2" must be single bits)
*/
#define _calc_vm_trans(x, bit1, bit2) \
((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
: ((x) & (bit1)) / ((bit1) / (bit2)))
/*
* Combine the mmap "prot" argument into "vm_flags" used internally.
*/
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 );
}
/*
* Combine the mmap "flags" argument into "vm_flags" used internally.
*/
static inline unsigned long
calc_vm_flag_bits(unsigned long flags)
{
return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) |
_calc_vm_trans(flags, MAP_DENYWRITE, VM_DENYWRITE ) |
_calc_vm_trans(flags, MAP_EXECUTABLE, VM_EXECUTABLE) |
_calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED );
}
#endif /* __KERNEL__ */
#endif /* _LINUX_MMAN_H */