mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
synced 2025-10-31 18:36:37 +00:00
b845f313d7
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>
97 lines
2.3 KiB
C
97 lines
2.3 KiB
C
#ifndef _LINUX_MMAN_H
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#define _LINUX_MMAN_H
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#include <asm/mman.h>
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#define MREMAP_MAYMOVE 1
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#define MREMAP_FIXED 2
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#define OVERCOMMIT_GUESS 0
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#define OVERCOMMIT_ALWAYS 1
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#define OVERCOMMIT_NEVER 2
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#ifdef __KERNEL__
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#include <linux/mm.h>
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#include <asm/atomic.h>
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extern int sysctl_overcommit_memory;
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extern int sysctl_overcommit_ratio;
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extern atomic_long_t vm_committed_space;
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#ifdef CONFIG_SMP
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extern void vm_acct_memory(long pages);
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#else
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static inline void vm_acct_memory(long pages)
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{
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atomic_long_add(pages, &vm_committed_space);
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}
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#endif
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static inline void vm_unacct_memory(long pages)
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{
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vm_acct_memory(-pages);
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}
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/*
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* Allow architectures to handle additional protection bits
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*/
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#ifndef arch_calc_vm_prot_bits
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#define arch_calc_vm_prot_bits(prot) 0
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#endif
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#ifndef arch_vm_get_page_prot
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#define arch_vm_get_page_prot(vm_flags) __pgprot(0)
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#endif
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#ifndef arch_validate_prot
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/*
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* This is called from mprotect(). PROT_GROWSDOWN and PROT_GROWSUP have
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* already been masked out.
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*
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* Returns true if the prot flags are valid
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*/
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static inline int arch_validate_prot(unsigned long prot)
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{
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return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
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}
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#define arch_validate_prot arch_validate_prot
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#endif
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/*
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* Optimisation macro. It is equivalent to:
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* (x & bit1) ? bit2 : 0
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* but this version is faster.
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* ("bit1" and "bit2" must be single bits)
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*/
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#define _calc_vm_trans(x, bit1, bit2) \
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((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
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: ((x) & (bit1)) / ((bit1) / (bit2)))
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/*
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* Combine the mmap "prot" argument into "vm_flags" used internally.
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*/
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static inline unsigned long
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calc_vm_prot_bits(unsigned long prot)
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{
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return _calc_vm_trans(prot, PROT_READ, VM_READ ) |
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_calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
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_calc_vm_trans(prot, PROT_EXEC, VM_EXEC) |
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arch_calc_vm_prot_bits(prot);
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}
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/*
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* Combine the mmap "flags" argument into "vm_flags" used internally.
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*/
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static inline unsigned long
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calc_vm_flag_bits(unsigned long flags)
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{
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return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) |
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_calc_vm_trans(flags, MAP_DENYWRITE, VM_DENYWRITE ) |
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_calc_vm_trans(flags, MAP_EXECUTABLE, VM_EXECUTABLE) |
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_calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED );
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}
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#endif /* __KERNEL__ */
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#endif /* _LINUX_MMAN_H */
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