[PATCH v2 3/4] arm: mm: introduce L_PTE_SPECIAL

[Miles Chen <miles.chen@mediatek.com>]

From: Minchan Kim <minchan@kernel.org>

This patch introduces L_PTE_SPECIAL and pte functions for supporting
get_user_pages_fast.

Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
---
 arch/arm/Kconfig                      |  4 ++--
 arch/arm/include/asm/pgtable-2level.h |  1 +
 arch/arm/include/asm/pgtable-3level.h |  6 ------
 arch/arm/include/asm/pgtable.h        | 13 +++++++++++++
 4 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index c18fa9d382b7..1f75864b7c7a 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -13,7 +13,7 @@ config ARM
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_MEMBARRIER_SYNC_CORE
 	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
-	select ARCH_HAS_PTE_SPECIAL if ARM_LPAE
+	select ARCH_HAS_PTE_SPECIAL if (ARM_LPAE || CPU_V7 || CPU_V6 || CPUV6K)
 	select ARCH_HAS_PHYS_TO_DMA
 	select ARCH_HAS_SETUP_DMA_OPS
 	select ARCH_HAS_SET_MEMORY
@@ -82,7 +82,7 @@ config ARM
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && MMU
 	select HAVE_EXIT_THREAD
-	select HAVE_FAST_GUP if ARM_LPAE
+	select HAVE_FAST_GUP if (ARM_LPAE || CPU_V7 || CPU_V6 || CPUV6K)
 	select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
 	select HAVE_FUNCTION_GRAPH_TRACER if !THUMB2_KERNEL && !CC_IS_CLANG
 	select HAVE_FUNCTION_TRACER if !XIP_KERNEL
diff --git a/arch/arm/include/asm/pgtable-2level.h b/arch/arm/include/asm/pgtable-2level.h
index cdcd55cca37d..385e7a32394e 100644
--- a/arch/arm/include/asm/pgtable-2level.h
+++ b/arch/arm/include/asm/pgtable-2level.h
@@ -117,6 +117,7 @@
 #define L_PTE_VALID		(_AT(pteval_t, 1) << 0)		/* Valid */
 #define L_PTE_PRESENT		(_AT(pteval_t, 1) << 0)
 #define L_PTE_YOUNG		(_AT(pteval_t, 1) << 1)
+#define L_PTE_SPECIAL		(_AT(pteval_t, 1) << 5)
 #define L_PTE_DIRTY		(_AT(pteval_t, 1) << 6)
 #define L_PTE_RDONLY		(_AT(pteval_t, 1) << 7)
 #define L_PTE_USER		(_AT(pteval_t, 1) << 8)
diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
index fbb6693c3352..46fcc6725d3e 100644
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -175,12 +175,6 @@ static inline pmd_t *pud_page_vaddr(pud_t pud)
 
 #define pmd_present(pmd)	(pmd_isset((pmd), L_PMD_SECT_VALID))
 #define pmd_young(pmd)		(pmd_isset((pmd), PMD_SECT_AF))
-#define pte_special(pte)	(pte_isset((pte), L_PTE_SPECIAL))
-static inline pte_t pte_mkspecial(pte_t pte)
-{
-	pte_val(pte) |= L_PTE_SPECIAL;
-	return pte;
-}
 
 #define pmd_write(pmd)		(pmd_isclear((pmd), L_PMD_SECT_RDONLY))
 #define pmd_dirty(pmd)		(pmd_isset((pmd), L_PMD_SECT_DIRTY))
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index c02f24400369..4092154ca779 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -195,6 +195,11 @@ static inline pte_t *pmd_page_vaddr(pmd_t pmd)
 #define pte_dirty(pte)		(pte_isset((pte), L_PTE_DIRTY))
 #define pte_young(pte)		(pte_isset((pte), L_PTE_YOUNG))
 #define pte_exec(pte)		(pte_isclear((pte), L_PTE_XN))
+#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
+#define pte_special(pte)	(pte_isset((pte), L_PTE_SPECIAL))
+#else
+#define pte_special(pte)	(0)
+#endif
 
 #define pte_valid_user(pte)	\
 	(pte_valid(pte) && pte_isset((pte), L_PTE_USER) && pte_young(pte))
@@ -274,6 +279,14 @@ static inline pte_t pte_mknexec(pte_t pte)
 	return set_pte_bit(pte, __pgprot(L_PTE_XN));
 }
 
+#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
+static inline pte_t pte_mkspecial(pte_t pte)
+{
+	return set_pte_bit(pte, __pgprot(L_PTE_SPECIAL));
+}
+#else
+static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
+#endif
 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 |
-- 
2.18.0