Re: [RFC v7 15/25] powerpc: Program HPTE key protection bits

[Laurent Dufour <ldufour@linux.vnet.ibm.com>]

On 31/07/2017 02:12, Ram Pai wrote:
> Map the PTE protection key bits to the HPTE key protection bits,
> while creating HPTE  entries.
> 
> Signed-off-by: Ram Pai <linuxram@us.ibm.com>
> ---
>  arch/powerpc/include/asm/book3s/64/mmu-hash.h |    5 +++++
>  arch/powerpc/include/asm/mmu_context.h        |    6 ++++++
>  arch/powerpc/include/asm/pkeys.h              |   13 +++++++++++++
>  arch/powerpc/mm/hash_utils_64.c               |    1 +
>  4 files changed, 25 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
> index 6981a52..f7a6ed3 100644
> --- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
> +++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
> @@ -90,6 +90,8 @@
>  #define HPTE_R_PP0		ASM_CONST(0x8000000000000000)
>  #define HPTE_R_TS		ASM_CONST(0x4000000000000000)
>  #define HPTE_R_KEY_HI		ASM_CONST(0x3000000000000000)
> +#define HPTE_R_KEY_BIT0		ASM_CONST(0x2000000000000000)
> +#define HPTE_R_KEY_BIT1		ASM_CONST(0x1000000000000000)
>  #define HPTE_R_RPN_SHIFT	12
>  #define HPTE_R_RPN		ASM_CONST(0x0ffffffffffff000)
>  #define HPTE_R_RPN_3_0		ASM_CONST(0x01fffffffffff000)
> @@ -104,6 +106,9 @@
>  #define HPTE_R_C		ASM_CONST(0x0000000000000080)
>  #define HPTE_R_R		ASM_CONST(0x0000000000000100)
>  #define HPTE_R_KEY_LO		ASM_CONST(0x0000000000000e00)
> +#define HPTE_R_KEY_BIT2		ASM_CONST(0x0000000000000800)
> +#define HPTE_R_KEY_BIT3		ASM_CONST(0x0000000000000400)
> +#define HPTE_R_KEY_BIT4		ASM_CONST(0x0000000000000200)
> 
>  #define HPTE_V_1TB_SEG		ASM_CONST(0x4000000000000000)
>  #define HPTE_V_VRMA_MASK	ASM_CONST(0x4001ffffff000000)
> diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
> index 7232484..2eb7f80 100644
> --- a/arch/powerpc/include/asm/mmu_context.h
> +++ b/arch/powerpc/include/asm/mmu_context.h
> @@ -190,6 +190,12 @@ static inline int vma_pkey(struct vm_area_struct *vma)
>  {
>  	return 0;
>  }
> +
> +static inline u64 pte_to_hpte_pkey_bits(u64 pteflags)
> +{
> +	return 0x0UL;
> +}
> +
>  #endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
> 
>  #endif /* __KERNEL__ */
> diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
> index 1ded6df..4b7e3f4 100644
> --- a/arch/powerpc/include/asm/pkeys.h
> +++ b/arch/powerpc/include/asm/pkeys.h
> @@ -72,6 +72,19 @@ static inline int vma_pkey(struct vm_area_struct *vma)
>  #define AMR_RD_BIT 0x1UL
>  #define AMR_WR_BIT 0x2UL
>  #define IAMR_EX_BIT 0x1UL
> +
> +static inline u64 pte_to_hpte_pkey_bits(u64 pteflags)
> +{
> +	if (!pkey_inited)
> +		return 0x0UL;

Why making such a check here, is it to avoid the following check during the
boot process only ?
IIUC, there is no way to get H_PAGE_PKEY_BIT* set when pkey_inited is false.

> +
> +	return (((pteflags & H_PAGE_PKEY_BIT0) ? HPTE_R_KEY_BIT0 : 0x0UL) |
> +		((pteflags & H_PAGE_PKEY_BIT1) ? HPTE_R_KEY_BIT1 : 0x0UL) |
> +		((pteflags & H_PAGE_PKEY_BIT2) ? HPTE_R_KEY_BIT2 : 0x0UL) |
> +		((pteflags & H_PAGE_PKEY_BIT3) ? HPTE_R_KEY_BIT3 : 0x0UL) |
> +		((pteflags & H_PAGE_PKEY_BIT4) ? HPTE_R_KEY_BIT4 : 0x0UL));
> +}
> +
>  #define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | \
>  				VM_PKEY_BIT3 | VM_PKEY_BIT4)
>  #define AMR_BITS_PER_PKEY 2
> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
> index f88423b..545f291 100644
> --- a/arch/powerpc/mm/hash_utils_64.c
> +++ b/arch/powerpc/mm/hash_utils_64.c
> @@ -231,6 +231,7 @@ unsigned long htab_convert_pte_flags(unsigned long pteflags)
>  		 */
>  		rflags |= HPTE_R_M;
> 
> +	rflags |= pte_to_hpte_pkey_bits(pteflags);
>  	return rflags;
>  }
>