helper function that checks if the read/write/execute is allowed on the pte.
Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/book3s/64/pgtable.h | 4 +++ arch/powerpc/include/asm/pkeys.h | 9 ++++++++ arch/powerpc/mm/pkeys.c | 28 ++++++++++++++++++++++++++ 3 files changed, 41 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index e1a8bb6..e785c68 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -462,6 +462,10 @@ static inline void huge_ptep_set_wrprotect(struct mm_struct *mm, pte_update(mm, addr, ptep, 0, _PAGE_PRIVILEGED, 1); }
+#ifdef CONFIG_PPC_MEM_KEYS +extern bool arch_pte_access_permitted(u64 pte, bool write, bool execute); +#endif /* CONFIG_PPC_MEM_KEYS */ + #define __HAVE_ARCH_PTEP_GET_AND_CLEAR static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 523d66c..7c45a40 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -82,6 +82,15 @@ static inline u64 pte_to_hpte_pkey_bits(u64 pteflags) ((pteflags & H_PTE_PKEY_BIT4) ? HPTE_R_KEY_BIT4 : 0x0UL)); }
+static inline u16 pte_to_pkey_bits(u64 pteflags) +{ + return (((pteflags & H_PTE_PKEY_BIT0) ? 0x10 : 0x0UL) | + ((pteflags & H_PTE_PKEY_BIT1) ? 0x8 : 0x0UL) | + ((pteflags & H_PTE_PKEY_BIT2) ? 0x4 : 0x0UL) | + ((pteflags & H_PTE_PKEY_BIT3) ? 0x2 : 0x0UL) | + ((pteflags & H_PTE_PKEY_BIT4) ? 0x1 : 0x0UL)); +} + #define pkey_alloc_mask(pkey) (0x1 << pkey)
#define mm_pkey_allocation_map(mm) (mm->context.pkey_allocation_map) diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index 7630c2f..0e044ea 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -362,3 +362,31 @@ int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot, /* Nothing to override. */ return vma_pkey(vma); } + +static bool pkey_access_permitted(int pkey, bool write, bool execute) +{ + int pkey_shift; + u64 amr; + + if (!pkey) + return true; + + if (!is_pkey_enabled(pkey)) + return true; + + pkey_shift = pkeyshift(pkey); + if (execute && !(read_iamr() & (IAMR_EX_BIT << pkey_shift))) + return true; + + amr = read_amr(); /* Delay reading amr until absolutely needed */ + return ((!write && !(amr & (AMR_RD_BIT << pkey_shift))) || + (write && !(amr & (AMR_WR_BIT << pkey_shift)))); +} + +bool arch_pte_access_permitted(u64 pte, bool write, bool execute) +{ + if (static_branch_likely(&pkey_disabled)) + return true; + + return pkey_access_permitted(pte_to_pkey_bits(pte), write, execute); +}