[PATCH V3 15/30] riscv/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

Anshuman Khandual
2022-02-28T10:59:38Z

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: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: linux-riscv@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/pgtable.h | 16 ------------
arch/riscv/mm/init.c | 42 ++++++++++++++++++++++++++++++++
3 files changed, 43 insertions(+), 16 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 5adcbd9b5e88..9391742f9286 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -31,6 +31,7 @@ config RISCV
select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAS_UBSAN_SANITIZE_ALL
+ select ARCH_HAS_VM_GET_PAGE_PROT
select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
select ARCH_STACKWALK
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 7e949f25c933..d2bb14cac28b 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -183,24 +183,8 @@ extern struct pt_alloc_ops pt_ops __initdata;
extern pgd_t swapper_pg_dir[];

/* MAP_PRIVATE permissions: xwr (copy-on-write) */
-#define __P000 PAGE_NONE
-#define __P001 PAGE_READ
-#define __P010 PAGE_COPY
-#define __P011 PAGE_COPY
-#define __P100 PAGE_EXEC
-#define __P101 PAGE_READ_EXEC
-#define __P110 PAGE_COPY_EXEC
-#define __P111 PAGE_COPY_READ_EXEC

/* MAP_SHARED permissions: xwr */
-#define __S000 PAGE_NONE
-#define __S001 PAGE_READ
-#define __S010 PAGE_SHARED
-#define __S011 PAGE_SHARED
-#define __S100 PAGE_EXEC
-#define __S101 PAGE_READ_EXEC
-#define __S110 PAGE_SHARED_EXEC
-#define __S111 PAGE_SHARED_EXEC

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static inline int pmd_present(pmd_t pmd)
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index c27294128e18..8cb5d1eeb287 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -1050,3 +1050,45 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
return vmemmap_populate_basepages(start, end, node, NULL);
}
#endif
+
+#ifdef CONFIG_MMU
+pgprot_t vm_get_page_prot(unsigned long vm_flags)
+{
+ switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) {
+ /* MAP_PRIVATE permissions: xwr (copy-on-write) */
+ case VM_NONE:
+ return PAGE_NONE;
+ case VM_READ:
+ return PAGE_READ;
+ case VM_WRITE:
+ case VM_WRITE | VM_READ:
+ return PAGE_COPY;
+ case VM_EXEC:
+ return PAGE_EXEC;
+ case VM_EXEC | VM_READ:
+ return PAGE_READ_EXEC;
+ case VM_EXEC | VM_WRITE:
+ return PAGE_COPY_EXEC;
+ case VM_EXEC | VM_WRITE | VM_READ:
+ return PAGE_COPY_READ_EXEC;
+ /* MAP_SHARED permissions: xwr */
+ case VM_SHARED:
+ return PAGE_NONE;
+ case VM_SHARED | VM_READ:
+ return PAGE_READ;
+ case VM_SHARED | VM_WRITE:
+ case VM_SHARED | VM_WRITE | VM_READ:
+ return PAGE_SHARED;
+ case VM_SHARED | VM_EXEC:
+ return PAGE_EXEC;
+ case VM_SHARED | VM_EXEC | VM_READ:
+ return PAGE_READ_EXEC;
+ case VM_SHARED | VM_EXEC | VM_WRITE:
+ case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ:
+ return PAGE_SHARED_EXEC;
+ default:
+ BUILD_BUG();
+ }
+}
+EXPORT_SYMBOL(vm_get_page_prot);
+#endif /* CONFIG_MMU */
--
2.25.1