[PATCH V4 3/7] arm64/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

Anshuman Khandual
2022-04-07T10:34:40Z

This defines and exports a platform specific custom vm_get_page_prot() via
subscribing ARCH_HAS_VM_GET_PAGE_PROT. It localizes arch_vm_get_page_prot()
and moves it 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 | 1 +
arch/arm64/include/asm/mman.h | 24 ------------------------
arch/arm64/mm/mmap.c | 33 +++++++++++++++++++++++++++++++++
3 files changed, 34 insertions(+), 24 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 57c4c995965f..dd0b15162bb3 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -45,6 +45,7 @@ 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..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/mm/mmap.c b/arch/arm64/mm/mmap.c
index 77ada00280d9..307534fcec00 100644
--- a/arch/arm64/mm/mmap.c
+++ b/arch/arm64/mm/mmap.c
@@ -55,3 +55,36 @@ static int __init adjust_protection_map(void)
return 0;
}
arch_initcall(adjust_protection_map);
+
+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(protection_map[vm_flags &
+ (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
+ pgprot_val(arm64_arch_vm_get_page_prot(vm_flags)));
+
+ return ret;
+}
+EXPORT_SYMBOL(vm_get_page_prot);
--
2.25.1