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Commit 1137573a authored by Ram Pai's avatar Ram Pai Committed by Michael Ellerman
Browse files

powerpc: implementation for arch_vma_access_permitted() 



This patch provides the implementation for
arch_vma_access_permitted(). Returns true if the
requested access is allowed by pkey associated with the
vma.

Signed-off-by: default avatarRam Pai <linuxram@us.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent bca7aacf

arch/powerpc/include/asm/mmu_context.h

+4 −1
Original line number Diff line number Diff line
@@ -186,6 +186,10 @@ static inline void arch_bprm_mm_init(struct mm_struct *mm, 
{

}



#ifdef CONFIG_PPC_MEM_KEYS

bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write,

			       bool execute, bool foreign);

#else /* CONFIG_PPC_MEM_KEYS */

static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,

		bool write, bool execute, bool foreign)

{
@@ -193,7 +197,6 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, 
	return true;

}



#ifndef CONFIG_PPC_MEM_KEYS

#define pkey_mm_init(mm)

#define thread_pkey_regs_save(thread)

#define thread_pkey_regs_restore(new_thread, old_thread)

arch/powerpc/mm/pkeys.c

+34 −0
Original line number Diff line number Diff line
@@ -386,3 +386,37 @@ bool arch_pte_access_permitted(u64 pte, bool write, bool execute) 


	return pkey_access_permitted(pte_to_pkey_bits(pte), write, execute);

}



/*

 * We only want to enforce protection keys on the current thread because we

 * effectively have no access to AMR/IAMR for other threads or any way to tell

 * which AMR/IAMR in a threaded process we could use.

 *

 * So do not enforce things if the VMA is not from the current mm, or if we are

 * in a kernel thread.

 */

static inline bool vma_is_foreign(struct vm_area_struct *vma)

{

	if (!current->mm)

		return true;



	/* if it is not our ->mm, it has to be foreign */

	if (current->mm != vma->vm_mm)

		return true;



	return false;

}



bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write,

			       bool execute, bool foreign)

{

	if (static_branch_likely(&pkey_disabled))

		return true;

	/*

	 * Do not enforce our key-permissions on a foreign vma.

	 */

	if (foreign || vma_is_foreign(vma))

		return true;



	return pkey_access_permitted(vma_pkey(vma), write, execute);

}