On Fri, 8 Sep 2017 15:44:57 -0700
Ram Pai <linux...@us.ibm.com> wrote:
> powerpc has hardware support to disable execute on a pkey.
> This patch enables the ability to create execute-disabled
> keys.
>
> Signed-off-by: Ram Pai <linux...@us.ibm.com>
> ---
> arch/powerpc/include/uapi/asm/mman.h | 6 ++++++
> arch/powerpc/mm/pkeys.c | 16 ++++++++++++++++
> 2 files changed, 22 insertions(+), 0 deletions(-)
>
> diff --git a/arch/powerpc/include/uapi/asm/mman.h
> b/arch/powerpc/include/uapi/asm/mman.h
> index ab45cc2..f272b09 100644
> --- a/arch/powerpc/include/uapi/asm/mman.h
> +++ b/arch/powerpc/include/uapi/asm/mman.h
> @@ -45,4 +45,10 @@
> #define MAP_HUGE_1GB (30 << MAP_HUGE_SHIFT) /* 1GB HugeTLB Page */
> #define MAP_HUGE_16GB (34 << MAP_HUGE_SHIFT) /* 16GB HugeTLB Page */
>
> +/* override any generic PKEY Permission defines */
> +#define PKEY_DISABLE_EXECUTE 0x4
> +#undef PKEY_ACCESS_MASK
> +#define PKEY_ACCESS_MASK (PKEY_DISABLE_ACCESS |\
> + PKEY_DISABLE_WRITE |\
> + PKEY_DISABLE_EXECUTE)
> #endif /* _UAPI_ASM_POWERPC_MMAN_H */
> diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
> index cc5be6a..2282864 100644
> --- a/arch/powerpc/mm/pkeys.c
> +++ b/arch/powerpc/mm/pkeys.c
> @@ -24,6 +24,14 @@ void __init pkey_initialize(void)
> {
> int os_reserved, i;
>
> + /*
> + * we define PKEY_DISABLE_EXECUTE in addition to the arch-neutral
> + * generic defines for PKEY_DISABLE_ACCESS and PKEY_DISABLE_WRITE.
> + * Ensure that the bits a distinct.
> + */
> + BUILD_BUG_ON(PKEY_DISABLE_EXECUTE &
> + (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE));
Will these values every change? It's good to have I guess.
> +
> /* disable the pkey system till everything
> * is in place. A patch further down the
> * line will enable it.
> @@ -120,10 +128,18 @@ int __arch_set_user_pkey_access(struct task_struct
> *tsk, int pkey,
> unsigned long init_val)
> {
> u64 new_amr_bits = 0x0ul;
> + u64 new_iamr_bits = 0x0ul;
>
> if (!is_pkey_enabled(pkey))
> return -EINVAL;
>
> + if ((init_val & PKEY_DISABLE_EXECUTE)) {
> + if (!pkey_execute_disable_support)
> + return -EINVAL;
> + new_iamr_bits |= IAMR_EX_BIT;
> + }
> + init_iamr(pkey, new_iamr_bits);
> +
Where do we check the reserved keys?
Balbir Singh.
