[PATCH 3/5] arm: Use the generic devmem_is_allowed()

[Palmer Dabbelt]

From: Palmer Dabbelt <palmerdabbelt at google.com>

This is exactly the same as the arm64 version, which I recently copied
into lib/ for use by the RISC-V port.

[I haven't even build tested this.  The lib/ patch is on riscv/for-next,
which I'm targeting for 5.9, so this won't work alone.  See the cover
letter for more details.]

Signed-off-by: Palmer Dabbelt <palmerdabbelt at google.com>
---
 arch/arm/Kconfig          |  1 +
 arch/arm/include/asm/io.h |  1 -
 arch/arm/mm/mmap.c        | 22 ----------------------
 3 files changed, 1 insertion(+), 23 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2ac74904a3ce..0c9da68835c2 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -54,6 +54,7 @@ config ARM
 	select GENERIC_IRQ_PROBE
 	select GENERIC_IRQ_SHOW
 	select GENERIC_IRQ_SHOW_LEVEL
+	select GENERIC_LIB_DEVMEM_IS_ALLOWED
 	select GENERIC_PCI_IOMAP
 	select GENERIC_SCHED_CLOCK
 	select GENERIC_SMP_IDLE_THREAD
diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
index ab2b654084fa..fc748122f1e0 100644
--- a/arch/arm/include/asm/io.h
+++ b/arch/arm/include/asm/io.h
@@ -441,7 +441,6 @@ extern void pci_iounmap(struct pci_dev *dev, void __iomem *addr);
 #define ARCH_HAS_VALID_PHYS_ADDR_RANGE
 extern int valid_phys_addr_range(phys_addr_t addr, size_t size);
 extern int valid_mmap_phys_addr_range(unsigned long pfn, size_t size);
-extern int devmem_is_allowed(unsigned long pfn);
 #endif
 
 /*
diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index b8d912ac9e61..a0f8a0ca0788 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -165,25 +165,3 @@ int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
 {
 	return (pfn + (size >> PAGE_SHIFT)) <= (1 + (PHYS_MASK >> PAGE_SHIFT));
 }
-
-#ifdef CONFIG_STRICT_DEVMEM
-
-#include <linux/ioport.h>
-
-/*
- * devmem_is_allowed() checks to see if /dev/mem access to a certain
- * address is valid. The argument is a physical page number.
- * We mimic x86 here by disallowing access to system RAM as well as
- * device-exclusive MMIO regions. This effectively disable read()/write()
- * on /dev/mem.
- */
-int devmem_is_allowed(unsigned long pfn)
-{
-	if (iomem_is_exclusive(pfn << PAGE_SHIFT))
-		return 0;
-	if (!page_is_ram(pfn))
-		return 1;
-	return 0;
-}
-
-#endif
-- 
2.27.0.383.g050319c2ae-goog