diff options
Diffstat (limited to 'include/asm-s390/pgtable.h')
| -rw-r--r-- | include/asm-s390/pgtable.h | 146 |
1 files changed, 130 insertions, 16 deletions
diff --git a/include/asm-s390/pgtable.h b/include/asm-s390/pgtable.h index 304ee77..13c1654 100644 --- a/include/asm-s390/pgtable.h +++ b/include/asm-s390/pgtable.h @@ -224,6 +224,8 @@ extern unsigned long vmalloc_end; #define _PAGE_TYPE_FILE 0x601 /* bit 0x002 is used for offset !! */ #define _PAGE_TYPE_RO 0x200 #define _PAGE_TYPE_RW 0x000 +#define _PAGE_TYPE_EX_RO 0x202 +#define _PAGE_TYPE_EX_RW 0x002 /* * PTE type bits are rather complicated. handle_pte_fault uses pte_present, @@ -244,11 +246,13 @@ extern unsigned long vmalloc_end; * _PAGE_TYPE_FILE 11?1 -> 11?1 * _PAGE_TYPE_RO 0100 -> 1100 * _PAGE_TYPE_RW 0000 -> 1000 + * _PAGE_TYPE_EX_RO 0110 -> 1110 + * _PAGE_TYPE_EX_RW 0010 -> 1010 * - * pte_none is true for bits combinations 1000, 1100 + * pte_none is true for bits combinations 1000, 1010, 1100, 1110 * pte_present is true for bits combinations 0000, 0010, 0100, 0110, 1001 * pte_file is true for bits combinations 1101, 1111 - * swap pte is 1011 and 0001, 0011, 0101, 0111, 1010 and 1110 are invalid. + * swap pte is 1011 and 0001, 0011, 0101, 0111 are invalid. */ #ifndef __s390x__ @@ -313,33 +317,100 @@ extern unsigned long vmalloc_end; #define PAGE_NONE __pgprot(_PAGE_TYPE_NONE) #define PAGE_RO __pgprot(_PAGE_TYPE_RO) #define PAGE_RW __pgprot(_PAGE_TYPE_RW) +#define PAGE_EX_RO __pgprot(_PAGE_TYPE_EX_RO) +#define PAGE_EX_RW __pgprot(_PAGE_TYPE_EX_RW) #define PAGE_KERNEL PAGE_RW #define PAGE_COPY PAGE_RO /* - * The S390 can't do page protection for execute, and considers that the - * same are read. Also, write permissions imply read permissions. This is - * the closest we can get.. + * Dependent on the EXEC_PROTECT option s390 can do execute protection. + * Write permission always implies read permission. In theory with a + * primary/secondary page table execute only can be implemented but + * it would cost an additional bit in the pte to distinguish all the + * different pte types. To avoid that execute permission currently + * implies read permission as well. */ /*xwr*/ #define __P000 PAGE_NONE #define __P001 PAGE_RO #define __P010 PAGE_RO #define __P011 PAGE_RO -#define __P100 PAGE_RO -#define __P101 PAGE_RO -#define __P110 PAGE_RO -#define __P111 PAGE_RO +#define __P100 PAGE_EX_RO +#define __P101 PAGE_EX_RO +#define __P110 PAGE_EX_RO +#define __P111 PAGE_EX_RO #define __S000 PAGE_NONE #define __S001 PAGE_RO #define __S010 PAGE_RW #define __S011 PAGE_RW -#define __S100 PAGE_RO -#define __S101 PAGE_RO -#define __S110 PAGE_RW -#define __S111 PAGE_RW +#define __S100 PAGE_EX_RO +#define __S101 PAGE_EX_RO +#define __S110 PAGE_EX_RW +#define __S111 PAGE_EX_RW + +#ifndef __s390x__ +# define PMD_SHADOW_SHIFT 1 +# define PGD_SHADOW_SHIFT 1 +#else /* __s390x__ */ +# define PMD_SHADOW_SHIFT 2 +# define PGD_SHADOW_SHIFT 2 +#endif /* __s390x__ */ + +static inline struct page *get_shadow_page(struct page *page) +{ + if (s390_noexec && !list_empty(&page->lru)) + return virt_to_page(page->lru.next); + return NULL; +} + +static inline pte_t *get_shadow_pte(pte_t *ptep) +{ + unsigned long pteptr = (unsigned long) (ptep); + + if (s390_noexec) { + unsigned long offset = pteptr & (PAGE_SIZE - 1); + void *addr = (void *) (pteptr ^ offset); + struct page *page = virt_to_page(addr); + if (!list_empty(&page->lru)) + return (pte_t *) ((unsigned long) page->lru.next | + offset); + } + return NULL; +} + +static inline pmd_t *get_shadow_pmd(pmd_t *pmdp) +{ + unsigned long pmdptr = (unsigned long) (pmdp); + + if (s390_noexec) { + unsigned long offset = pmdptr & + ((PAGE_SIZE << PMD_SHADOW_SHIFT) - 1); + void *addr = (void *) (pmdptr ^ offset); + struct page *page = virt_to_page(addr); + if (!list_empty(&page->lru)) + return (pmd_t *) ((unsigned long) page->lru.next | + offset); + } + return NULL; +} + +static inline pgd_t *get_shadow_pgd(pgd_t *pgdp) +{ + unsigned long pgdptr = (unsigned long) (pgdp); + + if (s390_noexec) { + unsigned long offset = pgdptr & + ((PAGE_SIZE << PGD_SHADOW_SHIFT) - 1); + void *addr = (void *) (pgdptr ^ offset); + struct page *page = virt_to_page(addr); + if (!list_empty(&page->lru)) + return (pgd_t *) ((unsigned long) page->lru.next | + offset); + } + return NULL; +} /* * Certain architectures need to do special things when PTEs @@ -348,7 +419,16 @@ extern unsigned long vmalloc_end; */ static inline void set_pte(pte_t *pteptr, pte_t pteval) { + pte_t *shadow_pte = get_shadow_pte(pteptr); + *pteptr = pteval; + if (shadow_pte) { + if (!(pte_val(pteval) & _PAGE_INVALID) && + (pte_val(pteval) & _PAGE_SWX)) + pte_val(*shadow_pte) = pte_val(pteval) | _PAGE_RO; + else + pte_val(*shadow_pte) = _PAGE_TYPE_EMPTY; + } } #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval) @@ -466,7 +546,7 @@ static inline int pte_read(pte_t pte) static inline void pgd_clear(pgd_t * pgdp) { } -static inline void pmd_clear(pmd_t * pmdp) +static inline void pmd_clear_kernel(pmd_t * pmdp) { pmd_val(pmdp[0]) = _PAGE_TABLE_INV; pmd_val(pmdp[1]) = _PAGE_TABLE_INV; @@ -474,24 +554,55 @@ static inline void pmd_clear(pmd_t * pmdp) pmd_val(pmdp[3]) = _PAGE_TABLE_INV; } +static inline void pmd_clear(pmd_t * pmdp) +{ + pmd_t *shadow_pmd = get_shadow_pmd(pmdp); + + pmd_clear_kernel(pmdp); + if (shadow_pmd) + pmd_clear_kernel(shadow_pmd); +} + #else /* __s390x__ */ -static inline void pgd_clear(pgd_t * pgdp) +static inline void pgd_clear_kernel(pgd_t * pgdp) { pgd_val(*pgdp) = _PGD_ENTRY_INV | _PGD_ENTRY; } -static inline void pmd_clear(pmd_t * pmdp) +static inline void pgd_clear(pgd_t * pgdp) +{ + pgd_t *shadow_pgd = get_shadow_pgd(pgdp); + + pgd_clear_kernel(pgdp); + if (shadow_pgd) + pgd_clear_kernel(shadow_pgd); +} + +static inline void pmd_clear_kernel(pmd_t * pmdp) { pmd_val(*pmdp) = _PMD_ENTRY_INV | _PMD_ENTRY; pmd_val1(*pmdp) = _PMD_ENTRY_INV | _PMD_ENTRY; } +static inline void pmd_clear(pmd_t * pmdp) +{ + pmd_t *shadow_pmd = get_shadow_pmd(pmdp); + + pmd_clear_kernel(pmdp); + if (shadow_pmd) + pmd_clear_kernel(shadow_pmd); +} + #endif /* __s390x__ */ static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { + pte_t *shadow_pte = get_shadow_pte(ptep); + pte_val(*ptep) = _PAGE_TYPE_EMPTY; + if (shadow_pte) + pte_val(*shadow_pte) = _PAGE_TYPE_EMPTY; } /* @@ -609,8 +720,11 @@ ptep_clear_flush(struct vm_area_struct *vma, unsigned long address, pte_t *ptep) { pte_t pte = *ptep; + pte_t *shadow_pte = get_shadow_pte(ptep); __ptep_ipte(address, ptep); + if (shadow_pte) + __ptep_ipte(address, shadow_pte); return pte; } |