diff options
| author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2016-04-29 23:25:34 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2016-05-01 18:32:26 +1000 |
| commit | ac29c64089b74d107edb90879e63a2f7a03cd66b (patch) | |
| tree | 3143933d055f49376ec549cc3ffe76a224b23288 /arch/powerpc/mm/pgtable.c | |
| parent | e7bfc462d32fc417d3fea8ad07b62b59f000e925 (diff) | |
| download | lwn-ac29c64089b74d107edb90879e63a2f7a03cd66b.tar.gz lwn-ac29c64089b74d107edb90879e63a2f7a03cd66b.zip | |
powerpc/mm: Replace _PAGE_USER with _PAGE_PRIVILEGED
_PAGE_PRIVILEGED means the page can be accessed only by the kernel. This
is done to keep pte bits similar to PowerISA 3.0 Radix PTE format. User
pages are now marked by clearing _PAGE_PRIVILEGED bit.
Previously we allowed the kernel to have a privileged page in the lower
address range (USER_REGION). With this patch such access is denied.
We also prevent a kernel access to a non-privileged page in higher
address range (ie, REGION_ID != 0).
Both the above access scenarios should never happen.
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jeremy Kerr <jk@ozlabs.org>
Cc: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/mm/pgtable.c')
| -rw-r--r-- | arch/powerpc/mm/pgtable.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c index ef7b922c655c..125fb4b54445 100644 --- a/arch/powerpc/mm/pgtable.c +++ b/arch/powerpc/mm/pgtable.c @@ -43,9 +43,20 @@ static inline int is_exec_fault(void) */ static inline int pte_looks_normal(pte_t pte) { + +#if defined(CONFIG_PPC_BOOK3S_64) + if ((pte_val(pte) & + (_PAGE_PRESENT | _PAGE_SPECIAL | _PAGE_NO_CACHE)) == + _PAGE_PRESENT) { + if (pte_user(pte)) + return 1; + } + return 0; +#else return (pte_val(pte) & - (_PAGE_PRESENT | _PAGE_SPECIAL | _PAGE_NO_CACHE | _PAGE_USER)) == - (_PAGE_PRESENT | _PAGE_USER); + (_PAGE_PRESENT | _PAGE_SPECIAL | _PAGE_NO_CACHE | _PAGE_USER)) == + (_PAGE_PRESENT | _PAGE_USER); +#endif } static struct page *maybe_pte_to_page(pte_t pte) |