[PATCH V3 09/30] arm/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

Anshuman Khandual
2022-02-28T10:59:32Z

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.

Cc: Russell King <linux@armlinux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
arch/arm/Kconfig | 1 +
arch/arm/include/asm/pgtable.h | 20 +-------------
arch/arm/lib/uaccess_with_memcpy.c | 2 +-
arch/arm/mm/mmu.c | 44 ++++++++++++++++++++++++++----
4 files changed, 41 insertions(+), 26 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 4c97cb40eebb..87b2e89ef3d6 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -23,6 +23,7 @@ config ARM
select ARCH_HAS_SYNC_DMA_FOR_CPU if SWIOTLB || !MMU
select ARCH_HAS_TEARDOWN_DMA_OPS if MMU
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
+ select ARCH_HAS_VM_GET_PAGE_PROT
select ARCH_HAVE_CUSTOM_GPIO_H
select ARCH_HAVE_NMI_SAFE_CMPXCHG if CPU_V7 || CPU_V7M || CPU_V6K
select ARCH_HAS_GCOV_PROFILE_ALL
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index cd1f84bb40ae..64711716cd84 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -70,7 +70,7 @@ extern void __pgd_error(const char *file, int line, pgd_t);
#endif

/*
- * The pgprot_* and protection_map entries will be fixed up in runtime
+ * The pgprot_* entries will be fixed up in runtime in vm_get_page_prot()
* to include the cachable and bufferable bits based on memory policy,
* as well as any architecture dependent bits like global/ASID and SMP
* shared mapping bits.
@@ -137,24 +137,6 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
* 2) If we could do execute protection, then read is implied
* 3) write implies read permissions
*/
-#define __P000 __PAGE_NONE
-#define __P001 __PAGE_READONLY
-#define __P010 __PAGE_COPY
-#define __P011 __PAGE_COPY
-#define __P100 __PAGE_READONLY_EXEC
-#define __P101 __PAGE_READONLY_EXEC
-#define __P110 __PAGE_COPY_EXEC
-#define __P111 __PAGE_COPY_EXEC
-
-#define __S000 __PAGE_NONE
-#define __S001 __PAGE_READONLY
-#define __S010 __PAGE_SHARED
-#define __S011 __PAGE_SHARED
-#define __S100 __PAGE_READONLY_EXEC
-#define __S101 __PAGE_READONLY_EXEC
-#define __S110 __PAGE_SHARED_EXEC
-#define __S111 __PAGE_SHARED_EXEC
-
#ifndef __ASSEMBLY__
/*
* ZERO_PAGE is a global shared page that is always zero: used
diff --git a/arch/arm/lib/uaccess_with_memcpy.c b/arch/arm/lib/uaccess_with_memcpy.c
index 106f83a5ea6d..12d8d9794a28 100644
--- a/arch/arm/lib/uaccess_with_memcpy.c
+++ b/arch/arm/lib/uaccess_with_memcpy.c
@@ -247,7 +247,7 @@ static int __init test_size_treshold(void)
if (!dst_page)
goto no_dst;
kernel_ptr = page_address(src_page);
- user_ptr = vmap(&dst_page, 1, VM_IOREMAP, __pgprot(__P010));
+ user_ptr = vmap(&dst_page, 1, VM_IOREMAP, __pgprot(__PAGE_COPY));
if (!user_ptr)
goto no_vmap;

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 274e4f73fd33..9cdf45da57de 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -403,6 +403,8 @@ void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)
local_flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE);
}

+static pteval_t user_pgprot;
+
/*
* Adjust the PMD section entries according to the CPU in use.
*/
@@ -410,7 +412,7 @@ static void __init build_mem_type_table(void)
{
struct cachepolicy *cp;
unsigned int cr = get_cr();
- pteval_t user_pgprot, kern_pgprot, vecs_pgprot;
+ pteval_t kern_pgprot, vecs_pgprot;
int cpu_arch = cpu_architecture();
int i;

@@ -627,11 +629,6 @@ static void __init build_mem_type_table(void)
user_pgprot |= PTE_EXT_PXN;
#endif

- for (i = 0; i < 16; i++) {
- pteval_t v = pgprot_val(protection_map[i]);
- protection_map[i] = __pgprot(v | user_pgprot);
- }
-
mem_types[MT_LOW_VECTORS].prot_pte |= vecs_pgprot;
mem_types[MT_HIGH_VECTORS].prot_pte |= vecs_pgprot;

@@ -670,6 +667,41 @@ static void __init build_mem_type_table(void)
}
}

+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 __pgprot(pgprot_val(__PAGE_NONE) | user_pgprot);
+ case VM_READ:
+ return __pgprot(pgprot_val(__PAGE_READONLY) | user_pgprot);
+ case VM_WRITE:
+ case VM_WRITE | VM_READ:
+ return __pgprot(pgprot_val(__PAGE_COPY) | user_pgprot);
+ case VM_EXEC:
+ case VM_EXEC | VM_READ:
+ return __pgprot(pgprot_val(__PAGE_READONLY_EXEC) | user_pgprot);
+ case VM_EXEC | VM_WRITE:
+ case VM_EXEC | VM_WRITE | VM_READ:
+ return __pgprot(pgprot_val(__PAGE_COPY_EXEC) | user_pgprot);
+ case VM_SHARED:
+ return __pgprot(pgprot_val(__PAGE_NONE) | user_pgprot);
+ case VM_SHARED | VM_READ:
+ return __pgprot(pgprot_val(__PAGE_READONLY) | user_pgprot);
+ case VM_SHARED | VM_WRITE:
+ case VM_SHARED | VM_WRITE | VM_READ:
+ return __pgprot(pgprot_val(__PAGE_SHARED) | user_pgprot);
+ case VM_SHARED | VM_EXEC:
+ case VM_SHARED | VM_EXEC | VM_READ:
+ return __pgprot(pgprot_val(__PAGE_READONLY_EXEC) | user_pgprot);
+ case VM_SHARED | VM_EXEC | VM_WRITE:
+ case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ:
+ return __pgprot(pgprot_val(__PAGE_SHARED_EXEC) | user_pgprot);
+ default:
+ BUILD_BUG();
+ }
+}
+EXPORT_SYMBOL(vm_get_page_prot);
+
#ifdef CONFIG_ARM_DMA_MEM_BUFFERABLE
pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
unsigned long size, pgprot_t vma_prot)
--
2.25.1