[PATCH V3 05/30] arm64/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

Anshuman Khandual
2022-02-28T10:49:40Z

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. Moved both these localized functions near
vm_get_page_prot().

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/memory.h | 3 +-
arch/arm64/include/asm/mman.h | 24 ---------
arch/arm64/include/asm/pgtable-prot.h | 18 -------
arch/arm64/include/asm/pgtable.h | 11 ----
arch/arm64/mm/mmap.c | 78 +++++++++++++++++++++++++++
6 files changed, 80 insertions(+), 56 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 2e5d2eac6fc6..7153d5fff603 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/memory.h b/arch/arm64/include/asm/memory.h
index 0af70d9abede..64a613a0349b 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -126,8 +126,7 @@
* Memory types available.
*
* IMPORTANT: MT_NORMAL must be index 0 since vm_get_page_prot() may 'or' in
- * the MT_NORMAL_TAGGED memory type for PROT_MTE mappings. Note
- * that protection_map[] only contains MT_NORMAL attributes.
+ * the MT_NORMAL_TAGGED memory type for PROT_MTE mappings.
*/
#define MT_NORMAL 0
#define MT_NORMAL_TAGGED 1
diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h
index e3e28f7daf62..5966ee4a6154 100644
--- a/arch/arm64/include/asm/mman.h
+++ b/arch/arm64/include/asm/mman.h
@@ -35,30 +35,6 @@ 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)
-{
- pteval_t prot = 0;
-
- if (vm_flags & VM_ARM64_BTI)
- prot |= PTE_GP;
-
- /*
- * There are two conditions required for returning a Normal Tagged
- * memory type: (1) the user requested it via PROT_MTE passed to
- * mmap() or mprotect() and (2) the corresponding vma supports MTE. We
- * register (1) as VM_MTE in the vma->vm_flags and (2) as
- * VM_MTE_ALLOWED. Note that the latter can only be set during the
- * mmap() call since mprotect() does not accept MAP_* flags.
- * Checking for VM_MTE only is sufficient since arch_validate_flags()
- * does not permit (VM_MTE & !VM_MTE_ALLOWED).
- */
- if (vm_flags & VM_MTE)
- prot |= PTE_ATTRINDX(MT_NORMAL_TAGGED);
-
- 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..94e147e5456c 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -1017,17 +1017,6 @@ 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)
-{
- if (cpus_have_const_cap(ARM64_HAS_EPAN))
- return prot;
-
- if (pgprot_val(prot) != pgprot_val(PAGE_EXECONLY))
- return prot;
-
- return PAGE_READONLY_EXEC;
-}
-
static inline bool pud_sect_supported(void)
{
return PAGE_SIZE == SZ_4K;
diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c
index a38f54cd638c..bd0233d376a2 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 +39,80 @@ 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:
+ case VM_WRITE:
+ case VM_WRITE | VM_READ:
+ return PAGE_READONLY;
+ case VM_EXEC:
+ return PAGE_EXECONLY;
+ case VM_EXEC | VM_READ:
+ case VM_EXEC | VM_WRITE:
+ case VM_EXEC | VM_WRITE | VM_READ:
+ return PAGE_READONLY_EXEC;
+ case VM_SHARED:
+ return PAGE_NONE;
+ case VM_SHARED | VM_READ:
+ return PAGE_READONLY;
+ case VM_SHARED | VM_WRITE:
+ case VM_SHARED | VM_WRITE | VM_READ:
+ 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:
+ case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ:
+ return PAGE_SHARED_EXEC;
+ default:
+ BUILD_BUG();
+ }
+}
+
+static pgprot_t arm64_arch_filter_pgprot(pgprot_t prot)
+{
+ if (cpus_have_const_cap(ARM64_HAS_EPAN))
+ return prot;
+
+ if (pgprot_val(prot) != pgprot_val(PAGE_EXECONLY))
+ return prot;
+
+ return PAGE_READONLY_EXEC;
+}
+
+static pgprot_t arm64_arch_vm_get_page_prot(unsigned long vm_flags)
+{
+ pteval_t prot = 0;
+
+ if (vm_flags & VM_ARM64_BTI)
+ prot |= PTE_GP;
+
+ /*
+ * There are two conditions required for returning a Normal Tagged
+ * memory type: (1) the user requested it via PROT_MTE passed to
+ * mmap() or mprotect() and (2) the corresponding vma supports MTE. We
+ * register (1) as VM_MTE in the vma->vm_flags and (2) as
+ * VM_MTE_ALLOWED. Note that the latter can only be set during the
+ * mmap() call since mprotect() does not accept MAP_* flags.
+ * Checking for VM_MTE only is sufficient since arch_validate_flags()
+ * does not permit (VM_MTE & !VM_MTE_ALLOWED).
+ */
+ if (vm_flags & VM_MTE)
+ prot |= PTE_ATTRINDX(MT_NORMAL_TAGGED);
+
+ return __pgprot(prot);
+}
+
+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