From: Balbir Singh <bsingharora@gmail.com>
To: Ram Pai <linuxram@us.ibm.com>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org,
linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org
Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au,
khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com,
dave.hansen@intel.com, hbabu@us.ibm.com, arnd@arndb.de,
akpm@linux-foundation.org, corbet@lwn.net, mingo@redhat.com
Subject: Re: [RFC v3 02/23] powerpc: introduce set_hidx_slot helper
Date: Mon, 26 Jun 2017 09:03:18 +1000 [thread overview]
Message-ID: <1498431798.7935.5.camel@gmail.com> (raw)
In-Reply-To: <1498095579-6790-3-git-send-email-linuxram@us.ibm.com>
On Wed, 2017-06-21 at 18:39 -0700, Ram Pai wrote:
> Introduce set_hidx_slot() which sets the (H_PAGE_F_SECOND|H_PAGE_F_GIX)
> bits at the appropriate location in the PTE of 4K PTE. In the
> case of 64K PTE, it sets the bits in the second part of the PTE. Though
> the implementation for the former just needs the slot parameter, it does
> take some additional parameters to keep the prototype consistent.
>
> This function will come in handy as we work towards re-arranging the
> bits in the later patches.
>
> Signed-off-by: Ram Pai <linuxram@us.ibm.com>
> ---
> arch/powerpc/include/asm/book3s/64/hash-4k.h | 7 +++++++
> arch/powerpc/include/asm/book3s/64/hash-64k.h | 16 ++++++++++++++++
> 2 files changed, 23 insertions(+)
>
> diff --git a/arch/powerpc/include/asm/book3s/64/hash-4k.h b/arch/powerpc/include/asm/book3s/64/hash-4k.h
> index 9c2c8f1..cef644c 100644
> --- a/arch/powerpc/include/asm/book3s/64/hash-4k.h
> +++ b/arch/powerpc/include/asm/book3s/64/hash-4k.h
> @@ -55,6 +55,13 @@ static inline int hash__hugepd_ok(hugepd_t hpd)
> }
> #endif
>
> +static inline unsigned long set_hidx_slot(pte_t *ptep, real_pte_t rpte,
> + unsigned int subpg_index, unsigned long slot)
> +{
> + return (slot << H_PAGE_F_GIX_SHIFT) &
> + (H_PAGE_F_SECOND | H_PAGE_F_GIX);
> +}
> +
A comment on top would help explain that 4k and 64k are different, 64k
is a new layout.
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>
> static inline char *get_hpte_slot_array(pmd_t *pmdp)
> diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h
> index 3f49941..4bac70a 100644
> --- a/arch/powerpc/include/asm/book3s/64/hash-64k.h
> +++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h
> @@ -75,6 +75,22 @@ static inline unsigned long __rpte_to_hidx(real_pte_t rpte, unsigned long index)
> return (pte_val(rpte.pte) >> H_PAGE_F_GIX_SHIFT) & 0xf;
> }
>
> +static inline unsigned long set_hidx_slot(pte_t *ptep, real_pte_t rpte,
> + unsigned int subpg_index, unsigned long slot)
> +{
> + unsigned long *hidxp = (unsigned long *)(ptep + PTRS_PER_PTE);
> +
> + rpte.hidx &= ~(0xfUL << (subpg_index << 2));
> + *hidxp = rpte.hidx | (slot << (subpg_index << 2));
> + /*
> + * Avoid race with __real_pte()
> + * hidx must be committed to memory before committing
> + * the pte.
> + */
> + smp_wmb();
Whats the other paired barrier, is it in set_pte()?
> + return 0x0UL;
> +}
We return 0 here and slot information for 4k pages, it is not that
clear
Balbir Singh.
next prev parent reply other threads:[~2017-06-25 23:04 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-22 1:39 [RFC v3 00/23] powerpc: Memory Protection Keys Ram Pai
2017-06-22 1:39 ` [RFC v3 01/23] powerpc: Free up four 64K PTE bits in 4K backed HPTE pages Ram Pai
2017-06-22 9:21 ` Balbir Singh
2017-06-22 18:50 ` Ram Pai
2017-06-22 1:39 ` [RFC v3 02/23] powerpc: introduce set_hidx_slot helper Ram Pai
2017-06-25 23:03 ` Balbir Singh [this message]
2017-06-26 4:02 ` Benjamin Herrenschmidt
2017-06-27 0:17 ` Ram Pai
2017-06-27 0:16 ` Ram Pai
2017-06-22 1:39 ` [RFC v3 03/23] powerpc: introduce get_hidx_gslot helper Ram Pai
2017-06-22 1:39 ` [RFC v3 04/23] powerpc: Free up four 64K PTE bits in 64K backed HPTE pages Ram Pai
2017-06-22 1:39 ` [RFC v3 05/23] powerpc: capture the PTE format changes in the dump pte report Ram Pai
2017-06-22 1:39 ` [RFC v3 06/23] powerpc: use helper functions in __hash_page_4K() for 64K PTE Ram Pai
2017-06-22 1:39 ` [RFC v3 07/23] powerpc: use helper functions in __hash_page_4K() for 4K PTE Ram Pai
2017-06-22 1:39 ` [RFC v3 08/23] powerpc: use helper functions in flush_hash_page() Ram Pai
2017-06-22 1:39 ` [RFC v3 09/23] mm: introduce an additional vma bit for powerpc pkey Ram Pai
2017-06-22 1:39 ` [RFC v3 10/23] mm: provide the ability to disable execute on a key at creation Ram Pai
2017-06-22 1:39 ` [RFC v3 11/23] x86: key creation with PKEY_DISABLE_EXECUTE is disallowed Ram Pai
2017-06-22 1:39 ` [RFC v3 12/23] powerpc: Implement sys_pkey_alloc and sys_pkey_free system call Ram Pai
2017-06-22 1:39 ` [RFC v3 13/23] powerpc: store and restore the pkey state across context switches Ram Pai
2017-06-22 1:39 ` [RFC v3 14/23] powerpc: Implementation for sys_mprotect_pkey() system call Ram Pai
2017-06-22 1:39 ` [RFC v3 15/23] powerpc: Program HPTE key protection bits Ram Pai
2017-06-22 1:39 ` [RFC v3 16/23] powerpc: Macro the mask used for checking DSI exception Ram Pai
2017-06-22 1:39 ` [RFC v3 17/23] powerpc: Handle exceptions caused by violation of pkey protection Ram Pai
2017-06-22 1:39 ` [RFC v3 18/23] powerpc: Deliver SEGV signal on pkey violation Ram Pai
2017-06-22 1:39 ` [RFC v3 19/23] selftest: Move protecton key selftest to arch neutral directory Ram Pai
2017-06-22 1:39 ` [RFC v3 20/23] selftest: PowerPC specific test updates to memory protection keys Ram Pai
2017-06-22 1:39 ` [RFC v3 21/23] Documentation: Move protecton key documentation to arch neutral directory Ram Pai
2017-06-22 1:39 ` [RFC v3 22/23] Documentation: PowerPC specific updates to memory protection keys Ram Pai
2017-06-22 1:39 ` [RFC v3 23/23] procfs: display the protection-key number associated with a vma Ram Pai
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