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author | Ram Pai | 2018-01-19 02:50:39 +0100 |
---|---|---|
committer | Michael Ellerman | 2018-01-20 12:59:04 +0100 |
commit | 1137573acfe4c67cdd265bbfbd2d66ebe87d6325 (patch) | |
tree | b1607abe00f500dd4efa56371eb659adb1bf2b68 /arch/powerpc/mm | |
parent | powerpc: check key protection for user page access (diff) | |
download | kernel-qcow2-linux-1137573acfe4c67cdd265bbfbd2d66ebe87d6325.tar.gz kernel-qcow2-linux-1137573acfe4c67cdd265bbfbd2d66ebe87d6325.tar.xz kernel-qcow2-linux-1137573acfe4c67cdd265bbfbd2d66ebe87d6325.zip |
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: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/mm')
-rw-r--r-- | arch/powerpc/mm/pkeys.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index 5071778fdd20..4a885cc165e5 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -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); +} |