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Date: Wed, 18 Oct 2017 14:17:35 +1100
From: Balbir Singh <bsingharora@gmail.com>
To: Ram Pai <linuxram@us.ibm.com>
Cc: mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org,
 benh@kernel.crashing.org, paulus@samba.org, khandual@linux.vnet.ibm.com,
 aneesh.kumar@linux.vnet.ibm.com, hbabu@us.ibm.com, mhocko@kernel.org,
 bauerman@linux.vnet.ibm.com, ebiederm@xmission.com
Subject: Re: [PATCH 04/25] powerpc: helper function to read,write
 AMR,IAMR,UAMOR registers
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References: <1504910713-7094-1-git-send-email-linuxram@us.ibm.com>
 <1504910713-7094-13-git-send-email-linuxram@us.ibm.com>
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On Fri,  8 Sep 2017 15:44:52 -0700
Ram Pai <linuxram@us.ibm.com> wrote:

> Implements helper functions to read and write the key related
> registers; AMR, IAMR, UAMOR.
> 
> AMR register tracks the read,write permission of a key
> IAMR register tracks the execute permission of a key
> UAMOR register enables and disables a key
> 
> Signed-off-by: Ram Pai <linuxram@us.ibm.com>
> ---
>  arch/powerpc/include/asm/book3s/64/pgtable.h |   31 ++++++++++++++++++++++++++
>  1 files changed, 31 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
> index b9aff51..73ed52c 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> @@ -438,6 +438,37 @@ static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
>  		pte_update(mm, addr, ptep, 0, _PAGE_PRIVILEGED, 1);
>  }
>  
> +#include <asm/reg.h>
> +static inline u64 read_amr(void)
> +{
> +	return mfspr(SPRN_AMR);
> +}
> +static inline void write_amr(u64 value)
> +{
> +	mtspr(SPRN_AMR, value);
> +}

Do we care to validate values or is that in
the caller

> +extern bool pkey_execute_disable_support;
> +static inline u64 read_iamr(void)
> +{
> +	if (pkey_execute_disable_support)
> +		return mfspr(SPRN_IAMR);
> +	else
> +		return 0x0UL;
> +}
> +static inline void write_iamr(u64 value)
> +{
> +	if (pkey_execute_disable_support)
> +		mtspr(SPRN_IAMR, value);
> +}
> +static inline u64 read_uamor(void)
> +{
> +	return mfspr(SPRN_UAMOR);
> +}
> +static inline void write_uamor(u64 value)
> +{
> +	mtspr(SPRN_UAMOR, value);
> +}
> +
>  #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)

Looks reasonable otherwise

Acked-by: Balbir Singh <bsingharora@gmail.com>