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From:   Anshuman Khandual <anshuman.khandual@arm.com>
To:     linux-mm@kvack.org
Cc:     linux-kernel@vger.kernel.org, hch@infradead.org,
        akpm@linux-foundation.org,
        Anshuman Khandual <anshuman.khandual@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        linux-arm-kernel@lists.infradead.org
Subject: [RFC V1 05/31] arm64/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
Date:   Mon, 24 Jan 2022 18:26:42 +0530
Message-Id: <1643029028-12710-6-git-send-email-anshuman.khandual@arm.com>
In-Reply-To: <1643029028-12710-1-git-send-email-anshuman.khandual@arm.com>
References: <1643029028-12710-1-git-send-email-anshuman.khandual@arm.com>
Precedence: bulk

This defines and exports a platform specific custom vm_get_page_prot() via
subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX
macros can be dropped which are no longer needed. This also localizes both
arch_filter_pgprot and arch_vm_get_page_prot() helpers, unsubscribing from
ARCH_HAS_FILTER_PGPROT as well.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 arch/arm64/Kconfig                    |  2 +-
 arch/arm64/include/asm/mman.h         |  3 +-
 arch/arm64/include/asm/pgtable-prot.h | 18 ----------
 arch/arm64/include/asm/pgtable.h      |  2 +-
 arch/arm64/mm/mmap.c                  | 50 +++++++++++++++++++++++++++
 5 files changed, 53 insertions(+), 22 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index cad609528e58..fce2d0fc4ecc 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -23,7 +23,6 @@ config ARM64
 	select ARCH_HAS_DMA_PREP_COHERENT
 	select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
 	select ARCH_HAS_FAST_MULTIPLIER
-	select ARCH_HAS_FILTER_PGPROT
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_GIGANTIC_PAGE
@@ -44,6 +43,7 @@ config ARM64
 	select ARCH_HAS_SYSCALL_WRAPPER
 	select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
+	select ARCH_HAS_VM_GET_PAGE_PROT
 	select ARCH_HAS_ZONE_DMA_SET if EXPERT
 	select ARCH_HAVE_ELF_PROT
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h
index e3e28f7daf62..85f41f72a8b3 100644
--- a/arch/arm64/include/asm/mman.h
+++ b/arch/arm64/include/asm/mman.h
@@ -35,7 +35,7 @@ static inline unsigned long arch_calc_vm_flag_bits(unsigned long flags)
 }
 #define arch_calc_vm_flag_bits(flags) arch_calc_vm_flag_bits(flags)
 
-static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags)
+static inline pgprot_t arm64_arch_vm_get_page_prot(unsigned long vm_flags)
 {
 	pteval_t prot = 0;
 
@@ -57,7 +57,6 @@ static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags)
 
 	return __pgprot(prot);
 }
-#define arch_vm_get_page_prot(vm_flags) arch_vm_get_page_prot(vm_flags)
 
 static inline bool arch_validate_prot(unsigned long prot,
 	unsigned long addr __always_unused)
diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
index 7032f04c8ac6..d8ee0aa7886d 100644
--- a/arch/arm64/include/asm/pgtable-prot.h
+++ b/arch/arm64/include/asm/pgtable-prot.h
@@ -88,24 +88,6 @@ extern bool arm64_use_ng_mappings;
 #define PAGE_READONLY_EXEC	__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN)
 #define PAGE_EXECONLY		__pgprot(_PAGE_DEFAULT | PTE_RDONLY | PTE_NG | PTE_PXN)
 
-#define __P000  PAGE_NONE
-#define __P001  PAGE_READONLY
-#define __P010  PAGE_READONLY
-#define __P011  PAGE_READONLY
-#define __P100  PAGE_EXECONLY
-#define __P101  PAGE_READONLY_EXEC
-#define __P110  PAGE_READONLY_EXEC
-#define __P111  PAGE_READONLY_EXEC
-
-#define __S000  PAGE_NONE
-#define __S001  PAGE_READONLY
-#define __S010  PAGE_SHARED
-#define __S011  PAGE_SHARED
-#define __S100  PAGE_EXECONLY
-#define __S101  PAGE_READONLY_EXEC
-#define __S110  PAGE_SHARED_EXEC
-#define __S111  PAGE_SHARED_EXEC
-
 #endif /* __ASSEMBLY__ */
 
 #endif /* __ASM_PGTABLE_PROT_H */
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index c4ba047a82d2..5a73501a45ed 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -1017,7 +1017,7 @@ static inline bool arch_wants_old_prefaulted_pte(void)
 }
 #define arch_wants_old_prefaulted_pte	arch_wants_old_prefaulted_pte
 
-static inline pgprot_t arch_filter_pgprot(pgprot_t prot)
+static inline pgprot_t arm64_arch_filter_pgprot(pgprot_t prot)
 {
 	if (cpus_have_const_cap(ARM64_HAS_EPAN))
 		return prot;
diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c
index a38f54cd638c..ad605eb86d23 100644
--- a/arch/arm64/mm/mmap.c
+++ b/arch/arm64/mm/mmap.c
@@ -10,6 +10,7 @@
 #include <linux/types.h>
 
 #include <asm/page.h>
+#include <asm/mman.h>
 
 /*
  * You really shouldn't be using read() or write() on /dev/mem.  This might go
@@ -38,3 +39,52 @@ int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
 {
 	return !(((pfn << PAGE_SHIFT) + size) & ~PHYS_MASK);
 }
+
+static inline pgprot_t __vm_get_page_prot(unsigned long vm_flags)
+{
+	switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) {
+	case VM_NONE:
+		return PAGE_NONE;
+	case VM_READ:
+		return PAGE_READONLY;
+	case VM_WRITE:
+		return PAGE_READONLY;
+	case VM_READ | VM_WRITE:
+		return PAGE_READONLY;
+	case VM_EXEC:
+		return PAGE_EXECONLY;
+	case VM_EXEC | VM_READ:
+		return PAGE_READONLY_EXEC;
+	case VM_EXEC | VM_WRITE:
+		return PAGE_READONLY_EXEC;
+	case VM_EXEC | VM_READ | VM_WRITE:
+		return PAGE_READONLY_EXEC;
+	case VM_SHARED:
+		return PAGE_NONE;
+	case VM_SHARED | VM_READ:
+		return PAGE_READONLY;
+	case VM_SHARED | VM_WRITE:
+		return PAGE_SHARED;
+	case VM_SHARED | VM_READ | VM_WRITE:
+		return PAGE_SHARED;
+	case VM_SHARED | VM_EXEC:
+		return PAGE_EXECONLY;
+	case VM_SHARED | VM_EXEC | VM_READ:
+		return PAGE_READONLY_EXEC;
+	case VM_SHARED | VM_EXEC | VM_WRITE:
+		return PAGE_SHARED_EXEC;
+	case VM_SHARED | VM_EXEC | VM_READ | VM_WRITE:
+		return PAGE_SHARED_EXEC;
+	default:
+		BUILD_BUG();
+	}
+}
+
+pgprot_t vm_get_page_prot(unsigned long vm_flags)
+{
+	pgprot_t ret = __pgprot(pgprot_val(__vm_get_page_prot(vm_flags)) |
+			pgprot_val(arm64_arch_vm_get_page_prot(vm_flags)));
+
+	return arm64_arch_filter_pgprot(ret);
+}
+EXPORT_SYMBOL(vm_get_page_prot);
-- 
2.25.1