From: steve.capper@linaro.org (Steve Capper)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH V3 1/6] arm: mm: Introduce special ptes for LPAE
Date: Wed, 12 Mar 2014 13:40:18 +0000 [thread overview]
Message-ID: <1394631623-17883-2-git-send-email-steve.capper@linaro.org> (raw)
In-Reply-To: <1394631623-17883-1-git-send-email-steve.capper@linaro.org>
We need a mechanism to tag ptes as being special, this indicates that
no attempt should be made to access the underlying struct page *
associated with the pte. This is used by the fast_gup as it has no means
to access VMAs (that also contain this information) locklessly.
The L_PTE_SPECIAL bit is already allocated for LPAE, this patch modifies
pte_special and pte_mkspecial to make use of it, and defines
__HAVE_ARCH_PTE_SPECIAL.
Signed-off-by: Steve Capper <steve.capper@linaro.org>
---
arch/arm/include/asm/pgtable-2level.h | 2 ++
arch/arm/include/asm/pgtable-3level.h | 8 ++++++++
arch/arm/include/asm/pgtable.h | 3 ---
3 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/arch/arm/include/asm/pgtable-2level.h b/arch/arm/include/asm/pgtable-2level.h
index dfff709..26d1742 100644
--- a/arch/arm/include/asm/pgtable-2level.h
+++ b/arch/arm/include/asm/pgtable-2level.h
@@ -181,6 +181,8 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
#define pmd_addr_end(addr,end) (end)
#define set_pte_ext(ptep,pte,ext) cpu_set_pte_ext(ptep,pte,ext)
+#define pte_special(pte) (0)
+static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
/*
* We don't have huge page support for short descriptors, for the moment
diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
index 85c60ad..b286ba9 100644
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -207,6 +207,14 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
#define pte_huge(pte) (pte_val(pte) && !(pte_val(pte) & PTE_TABLE_BIT))
#define pte_mkhuge(pte) (__pte(pte_val(pte) & ~PTE_TABLE_BIT))
+#define pte_special(pte) (!!(pte_val(pte) & L_PTE_SPECIAL))
+static inline pte_t pte_mkspecial(pte_t pte)
+{
+ pte_val(pte) |= L_PTE_SPECIAL;
+ return pte;
+}
+#define __HAVE_ARCH_PTE_SPECIAL
+
#define pmd_young(pmd) (pmd_val(pmd) & PMD_SECT_AF)
#define __HAVE_ARCH_PMD_WRITE
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index 5478e5d..664d243 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -222,7 +222,6 @@ static inline pte_t *pmd_page_vaddr(pmd_t pmd)
#define pte_dirty(pte) (pte_val(pte) & L_PTE_DIRTY)
#define pte_young(pte) (pte_val(pte) & L_PTE_YOUNG)
#define pte_exec(pte) (!(pte_val(pte) & L_PTE_XN))
-#define pte_special(pte) (0)
#define pte_valid_user(pte) \
(pte_valid(pte) && (pte_val(pte) & L_PTE_USER) && pte_young(pte))
@@ -260,8 +259,6 @@ PTE_BIT_FUNC(mkyoung, |= L_PTE_YOUNG);
PTE_BIT_FUNC(mkexec, &= ~L_PTE_XN);
PTE_BIT_FUNC(mknexec, |= L_PTE_XN);
-static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
-
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
const pteval_t mask = L_PTE_XN | L_PTE_RDONLY | L_PTE_USER |
--
1.8.1.4
next prev parent reply other threads:[~2014-03-12 13:40 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-12 13:40 [RFC PATCH V3 0/6] get_user_pages_fast for ARM and ARM64 Steve Capper
2014-03-12 13:40 ` Steve Capper [this message]
2014-03-12 13:40 ` [RFC PATCH V3 2/6] arm: mm: Enable HAVE_RCU_TABLE_FREE logic Steve Capper
2014-03-12 13:40 ` [RFC PATCH V3 3/6] arm: mm: implement get_user_pages_fast Steve Capper
2014-03-12 14:18 ` Peter Zijlstra
2014-03-12 16:20 ` Steve Capper
2014-03-12 16:30 ` Peter Zijlstra
2014-03-12 16:42 ` Steve Capper
2014-03-12 16:32 ` Peter Zijlstra
2014-03-12 16:41 ` Steve Capper
2014-03-12 16:55 ` Will Deacon
2014-03-12 17:11 ` Peter Zijlstra
2014-03-14 11:47 ` Peter Zijlstra
2014-03-13 8:24 ` Steve Capper
2014-03-12 17:15 ` Catalin Marinas
2014-03-13 8:03 ` Steve Capper
2014-03-12 13:40 ` [RFC PATCH V3 4/6] arm64: Convert asm/tlb.h to generic mmu_gather Steve Capper
2014-03-12 13:40 ` [RFC PATCH V3 5/6] arm64: mm: Enable HAVE_RCU_TABLE_FREE logic Steve Capper
2014-03-12 13:40 ` [RFC PATCH V3 6/6] arm64: mm: Activate get_user_pages_fast for arm64 Steve Capper
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