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powerpc/mm: add exec protection on powerpc 603

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The 603 doesn't have a HASH table, TLB misses are handled by
software. It is then possible to generate page fault when
_PAGE_EXEC is not set like in nohash/32.

There is one "reserved" PTE bit available, this patch uses
it for _PAGE_EXEC.

In order to support it, set_pte_filter() and
set_access_flags_filter() are made common, and the handling
is made dependent on MMU_FTR_HPTE_TABLE

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Christophe Leroy
2018-11-28 17:21:10 +00:00
committed by Michael Ellerman
parent badb9687ce
commit 385e89d5b2
6 changed files with 26 additions and 25 deletions
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18
arch/powerpc/include/asm/book3s/32/pgtable.h
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@@ -10,9 +10,9 @@
/* And here we include common definitions */
#define _PAGE_KERNEL_RO 0
#define _PAGE_KERNEL_ROX 0
#define _PAGE_KERNEL_ROX (_PAGE_EXEC)
#define _PAGE_KERNEL_RW (_PAGE_DIRTY | _PAGE_RW)
#define _PAGE_KERNEL_RWX (_PAGE_DIRTY | _PAGE_RW)
#define _PAGE_KERNEL_RWX (_PAGE_DIRTY | _PAGE_RW | _PAGE_EXEC)
#define _PAGE_HPTEFLAGS _PAGE_HASHPTE
@@ -66,11 +66,11 @@ static inline bool pte_user(pte_t pte)
*/
#define PAGE_NONE __pgprot(_PAGE_BASE)
#define PAGE_SHARED __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW)
#define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW)
#define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_EXEC)
#define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_USER)
#define PAGE_COPY_X __pgprot(_PAGE_BASE | _PAGE_USER)
#define PAGE_COPY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
#define PAGE_READONLY __pgprot(_PAGE_BASE | _PAGE_USER)
#define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_USER)
#define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
/* Permission masks used for kernel mappings */
#define PAGE_KERNEL __pgprot(_PAGE_BASE | _PAGE_KERNEL_RW)
@@ -318,7 +318,7 @@ static inline void __ptep_set_access_flags(struct vm_area_struct *vma,
int psize)
{
unsigned long set = pte_val(entry) &
(_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_RW);
(_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_RW | _PAGE_EXEC);
pte_update(ptep, 0, set);
@@ -371,7 +371,7 @@ static inline int pte_dirty(pte_t pte) { return !!(pte_val(pte) & _PAGE_DIRTY);
static inline int pte_young(pte_t pte) { return !!(pte_val(pte) & _PAGE_ACCESSED); }
static inline int pte_special(pte_t pte) { return !!(pte_val(pte) & _PAGE_SPECIAL); }
static inline int pte_none(pte_t pte) { return (pte_val(pte) & ~_PTE_NONE_MASK) == 0; }
static inline bool pte_exec(pte_t pte) { return true; }
static inline bool pte_exec(pte_t pte) { return pte_val(pte) & _PAGE_EXEC; }
static inline int pte_present(pte_t pte)
{
@@ -438,7 +438,7 @@ static inline pte_t pte_wrprotect(pte_t pte)
static inline pte_t pte_exprotect(pte_t pte)
{
return pte;
return __pte(pte_val(pte) & ~_PAGE_EXEC);
}
static inline pte_t pte_mkclean(pte_t pte)
@@ -453,7 +453,7 @@ static inline pte_t pte_mkold(pte_t pte)
static inline pte_t pte_mkexec(pte_t pte)
{
return pte;
return __pte(pte_val(pte) | _PAGE_EXEC);
}
static inline pte_t pte_mkpte(pte_t pte)