[PATCH] mm: Define ARCH_HAS_FIRST_USER_ADDRESS

[Anshuman Khandual <anshuman.khandual@arm.com>]

Currently most platforms define FIRST_USER_ADDRESS as 0UL duplicating the
same code all over. Instead define a new option ARCH_HAS_FIRST_USER_ADDRESS
for those platforms which would override generic default FIRST_USER_ADDRESS
value 0UL. This makes it much cleaner with reduced code.

Cc: linux-alpha@vger.kernel.org
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-csky@vger.kernel.org
Cc: linux-hexagon@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-mips@vger.kernel.org
Cc: openrisc@lists.librecores.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-riscv@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Cc: linux-um@lists.infradead.org
Cc: linux-xtensa@linux-xtensa.org
Cc: x86@kernel.org
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 arch/alpha/include/asm/pgtable.h             | 1 -
 arch/arc/include/asm/pgtable.h               | 6 ------
 arch/arm/Kconfig                             | 1 +
 arch/arm64/include/asm/pgtable.h             | 2 --
 arch/csky/include/asm/pgtable.h              | 1 -
 arch/hexagon/include/asm/pgtable.h           | 3 ---
 arch/ia64/include/asm/pgtable.h              | 1 -
 arch/m68k/include/asm/pgtable_mm.h           | 1 -
 arch/microblaze/include/asm/pgtable.h        | 2 --
 arch/mips/include/asm/pgtable-32.h           | 1 -
 arch/mips/include/asm/pgtable-64.h           | 1 -
 arch/nds32/Kconfig                           | 1 +
 arch/nios2/include/asm/pgtable.h             | 2 --
 arch/openrisc/include/asm/pgtable.h          | 1 -
 arch/parisc/include/asm/pgtable.h            | 2 --
 arch/powerpc/include/asm/book3s/pgtable.h    | 1 -
 arch/powerpc/include/asm/nohash/32/pgtable.h | 1 -
 arch/powerpc/include/asm/nohash/64/pgtable.h | 2 --
 arch/riscv/include/asm/pgtable.h             | 2 --
 arch/s390/include/asm/pgtable.h              | 2 --
 arch/sh/include/asm/pgtable.h                | 2 --
 arch/sparc/include/asm/pgtable_32.h          | 1 -
 arch/sparc/include/asm/pgtable_64.h          | 3 ---
 arch/um/include/asm/pgtable-2level.h         | 1 -
 arch/um/include/asm/pgtable-3level.h         | 1 -
 arch/x86/include/asm/pgtable_types.h         | 2 --
 arch/xtensa/include/asm/pgtable.h            | 1 -
 include/linux/mm.h                           | 4 ++++
 mm/Kconfig                                   | 4 ++++
 29 files changed, 10 insertions(+), 43 deletions(-)

diff --git a/arch/alpha/include/asm/pgtable.h b/arch/alpha/include/asm/pgtable.h
index 8d856c62e22a..1a2fb0dc905b 100644
--- a/arch/alpha/include/asm/pgtable.h
+++ b/arch/alpha/include/asm/pgtable.h
@@ -46,7 +46,6 @@ struct vm_area_struct;
 #define PTRS_PER_PMD	(1UL << (PAGE_SHIFT-3))
 #define PTRS_PER_PGD	(1UL << (PAGE_SHIFT-3))
 #define USER_PTRS_PER_PGD	(TASK_SIZE / PGDIR_SIZE)
-#define FIRST_USER_ADDRESS	0UL
 
 /* Number of pointers that fit on a page:  this will go away. */
 #define PTRS_PER_PAGE	(1UL << (PAGE_SHIFT-3))
diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index 163641726a2b..a9fabfb70664 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -228,12 +228,6 @@
  */
 #define	USER_PTRS_PER_PGD	(TASK_SIZE / PGDIR_SIZE)
 
-/*
- * No special requirements for lowest virtual address we permit any user space
- * mapping to be mapped at.
- */
-#define FIRST_USER_ADDRESS      0UL
-
 
 /****************************************************************
  * Bucket load of VM Helpers
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 5da96f5df48f..ad086e6d7155 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -7,6 +7,7 @@ config ARM
 	select ARCH_HAS_DEBUG_VIRTUAL if MMU
 	select ARCH_HAS_DMA_WRITE_COMBINE if !ARM_DMA_MEM_BUFFERABLE
 	select ARCH_HAS_ELF_RANDOMIZE
+	select ARCH_HAS_FIRST_USER_ADDRESS
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_KEEPINITRD
 	select ARCH_HAS_KCOV
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 47027796c2f9..f6ab8b64967e 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -26,8 +26,6 @@
 
 #define vmemmap			((struct page *)VMEMMAP_START - (memstart_addr >> PAGE_SHIFT))
 
-#define FIRST_USER_ADDRESS	0UL
-
 #ifndef __ASSEMBLY__
 
 #include <asm/cmpxchg.h>
diff --git a/arch/csky/include/asm/pgtable.h b/arch/csky/include/asm/pgtable.h
index 0d60367b6bfa..151607ed5158 100644
--- a/arch/csky/include/asm/pgtable.h
+++ b/arch/csky/include/asm/pgtable.h
@@ -14,7 +14,6 @@
 #define PGDIR_MASK		(~(PGDIR_SIZE-1))
 
 #define USER_PTRS_PER_PGD	(PAGE_OFFSET/PGDIR_SIZE)
-#define FIRST_USER_ADDRESS	0UL
 
 /*
  * C-SKY is two-level paging structure:
diff --git a/arch/hexagon/include/asm/pgtable.h b/arch/hexagon/include/asm/pgtable.h
index dbb22b80b8c4..e4979508cddf 100644
--- a/arch/hexagon/include/asm/pgtable.h
+++ b/arch/hexagon/include/asm/pgtable.h
@@ -155,9 +155,6 @@ extern unsigned long _dflt_cache_att;
 
 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];  /* located in head.S */
 
-/* Seems to be zero even in architectures where the zero page is firewalled? */
-#define FIRST_USER_ADDRESS 0UL
-
 /*  HUGETLB not working currently  */
 #ifdef CONFIG_HUGETLB_PAGE
 #define pte_mkhuge(pte) __pte((pte_val(pte) & ~0x3) | HVM_HUGEPAGE_SIZE)
diff --git a/arch/ia64/include/asm/pgtable.h b/arch/ia64/include/asm/pgtable.h
index 9b4efe89e62d..b37381532c2f 100644
--- a/arch/ia64/include/asm/pgtable.h
+++ b/arch/ia64/include/asm/pgtable.h
@@ -128,7 +128,6 @@
 #define PTRS_PER_PGD_SHIFT	PTRS_PER_PTD_SHIFT
 #define PTRS_PER_PGD		(1UL << PTRS_PER_PGD_SHIFT)
 #define USER_PTRS_PER_PGD	(5*PTRS_PER_PGD/8)	/* regions 0-4 are user regions */
-#define FIRST_USER_ADDRESS	0UL
 
 /*
  * All the normal masks have the "page accessed" bits on, as any time
diff --git a/arch/m68k/include/asm/pgtable_mm.h b/arch/m68k/include/asm/pgtable_mm.h
index aca22c2c1ee2..143ba7de9bda 100644
--- a/arch/m68k/include/asm/pgtable_mm.h
+++ b/arch/m68k/include/asm/pgtable_mm.h
@@ -72,7 +72,6 @@
 #define PTRS_PER_PGD	128
 #endif
 #define USER_PTRS_PER_PGD	(TASK_SIZE/PGDIR_SIZE)
-#define FIRST_USER_ADDRESS	0UL
 
 /* Virtual address region for use by kernel_map() */
 #ifdef CONFIG_SUN3
diff --git a/arch/microblaze/include/asm/pgtable.h b/arch/microblaze/include/asm/pgtable.h
index 9ae8d2c17dd5..71cd547655d9 100644
--- a/arch/microblaze/include/asm/pgtable.h
+++ b/arch/microblaze/include/asm/pgtable.h
@@ -25,8 +25,6 @@ extern int mem_init_done;
 #include <asm/mmu.h>
 #include <asm/page.h>
 
-#define FIRST_USER_ADDRESS	0UL
-
 extern unsigned long va_to_phys(unsigned long address);
 extern pte_t *va_to_pte(unsigned long address);
 
diff --git a/arch/mips/include/asm/pgtable-32.h b/arch/mips/include/asm/pgtable-32.h
index 6c0532d7b211..95df9c293d8d 100644
--- a/arch/mips/include/asm/pgtable-32.h
+++ b/arch/mips/include/asm/pgtable-32.h
@@ -93,7 +93,6 @@ extern int add_temporary_entry(unsigned long entrylo0, unsigned long entrylo1,
 #endif
 
 #define USER_PTRS_PER_PGD	(0x80000000UL/PGDIR_SIZE)
-#define FIRST_USER_ADDRESS	0UL
 
 #define VMALLOC_START	  MAP_BASE
 
diff --git a/arch/mips/include/asm/pgtable-64.h b/arch/mips/include/asm/pgtable-64.h
index 1e7d6ce9d8d6..046465906c82 100644
--- a/arch/mips/include/asm/pgtable-64.h
+++ b/arch/mips/include/asm/pgtable-64.h
@@ -137,7 +137,6 @@
 #define PTRS_PER_PTE	((PAGE_SIZE << PTE_ORDER) / sizeof(pte_t))
 
 #define USER_PTRS_PER_PGD       ((TASK_SIZE64 / PGDIR_SIZE)?(TASK_SIZE64 / PGDIR_SIZE):1)
-#define FIRST_USER_ADDRESS	0UL
 
 /*
  * TLB refill handlers also map the vmalloc area into xuseg.  Avoid
diff --git a/arch/nds32/Kconfig b/arch/nds32/Kconfig
index 62313902d75d..23ec4fcc0d0f 100644
--- a/arch/nds32/Kconfig
+++ b/arch/nds32/Kconfig
@@ -8,6 +8,7 @@ config NDS32
 	def_bool y
 	select ARCH_32BIT_OFF_T
 	select ARCH_HAS_DMA_PREP_COHERENT
+	select ARCH_HAS_FIRST_USER_ADDRESS
 	select ARCH_HAS_SYNC_DMA_FOR_CPU
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
 	select ARCH_WANT_FRAME_POINTERS if FTRACE
diff --git a/arch/nios2/include/asm/pgtable.h b/arch/nios2/include/asm/pgtable.h
index 2600d76c310c..4a995fa628ee 100644
--- a/arch/nios2/include/asm/pgtable.h
+++ b/arch/nios2/include/asm/pgtable.h
@@ -24,8 +24,6 @@
 #include <asm/pgtable-bits.h>
 #include <asm-generic/pgtable-nopmd.h>
 
-#define FIRST_USER_ADDRESS	0UL
-
 #define VMALLOC_START		CONFIG_NIOS2_KERNEL_MMU_REGION_BASE
 #define VMALLOC_END		(CONFIG_NIOS2_KERNEL_REGION_BASE - 1)
 
diff --git a/arch/openrisc/include/asm/pgtable.h b/arch/openrisc/include/asm/pgtable.h
index 9425bedab4fc..4ac591c9ca33 100644
--- a/arch/openrisc/include/asm/pgtable.h
+++ b/arch/openrisc/include/asm/pgtable.h
@@ -73,7 +73,6 @@ extern void paging_init(void);
  */
 
 #define USER_PTRS_PER_PGD       (TASK_SIZE/PGDIR_SIZE)
-#define FIRST_USER_ADDRESS      0UL
 
 /*
  * Kernels own virtual memory area.
diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h
index 39017210dbf0..7f33c29764cc 100644
--- a/arch/parisc/include/asm/pgtable.h
+++ b/arch/parisc/include/asm/pgtable.h
@@ -171,8 +171,6 @@ static inline void purge_tlb_entries(struct mm_struct *mm, unsigned long addr)
  * pgd entries used up by user/kernel:
  */
 
-#define FIRST_USER_ADDRESS	0UL
-
 /* NB: The tlb miss handlers make certain assumptions about the order */
 /*     of the following bits, so be careful (One example, bits 25-31  */
 /*     are moved together in one instruction).                        */
diff --git a/arch/powerpc/include/asm/book3s/pgtable.h b/arch/powerpc/include/asm/book3s/pgtable.h
index 0e1263455d73..ad130e15a126 100644
--- a/arch/powerpc/include/asm/book3s/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/pgtable.h
@@ -8,7 +8,6 @@
 #include <asm/book3s/32/pgtable.h>
 #endif
 
-#define FIRST_USER_ADDRESS	0UL
 #ifndef __ASSEMBLY__
 /* Insert a PTE, top-level function is out of line. It uses an inline
  * low level function in the respective pgtable-* files
diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h
index 96522f7f0618..f06ae00f2a65 100644
--- a/arch/powerpc/include/asm/nohash/32/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
@@ -54,7 +54,6 @@ extern int icache_44x_need_flush;
 #define PGD_MASKED_BITS		0
 
 #define USER_PTRS_PER_PGD	(TASK_SIZE / PGDIR_SIZE)
-#define FIRST_USER_ADDRESS	0UL
 
 #define pte_ERROR(e) \
 	pr_err("%s:%d: bad pte %llx.\n", __FILE__, __LINE__, \
diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h b/arch/powerpc/include/asm/nohash/64/pgtable.h
index 6cb8aa357191..e40fb54af7ef 100644
--- a/arch/powerpc/include/asm/nohash/64/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/64/pgtable.h
@@ -10,8 +10,6 @@
 #include <asm/barrier.h>
 #include <asm/asm-const.h>
 
-#define FIRST_USER_ADDRESS	0UL
-
 /*
  * Size of EA range mapped by our pagetables.
  */
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index ebf817c1bdf4..1893dc9f0974 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -490,8 +490,6 @@ void setup_bootmem(void);
 void paging_init(void);
 void misc_mem_init(void);
 
-#define FIRST_USER_ADDRESS  0
-
 /*
  * ZERO_PAGE is a global shared page that is always zero,
  * used for zero-mapped memory areas, etc.
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 29c7ecd5ad1d..4ee49bb98f34 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -65,8 +65,6 @@ extern unsigned long zero_page_mask;
 
 /* TODO: s390 cannot support io_remap_pfn_range... */
 
-#define FIRST_USER_ADDRESS  0UL
-
 #define pte_ERROR(e) \
 	printk("%s:%d: bad pte %p.\n", __FILE__, __LINE__, (void *) pte_val(e))
 #define pmd_ERROR(e) \
diff --git a/arch/sh/include/asm/pgtable.h b/arch/sh/include/asm/pgtable.h
index 27751e9470df..d7ddb1ec86a0 100644
--- a/arch/sh/include/asm/pgtable.h
+++ b/arch/sh/include/asm/pgtable.h
@@ -59,8 +59,6 @@ static inline unsigned long long neff_sign_extend(unsigned long val)
 /* Entries per level */
 #define PTRS_PER_PTE	(PAGE_SIZE / (1 << PTE_MAGNITUDE))
 
-#define FIRST_USER_ADDRESS	0UL
-
 #define PHYS_ADDR_MASK29		0x1fffffff
 #define PHYS_ADDR_MASK32		0xffffffff
 
diff --git a/arch/sparc/include/asm/pgtable_32.h b/arch/sparc/include/asm/pgtable_32.h
index 632cdb959542..a732961da91d 100644
--- a/arch/sparc/include/asm/pgtable_32.h
+++ b/arch/sparc/include/asm/pgtable_32.h
@@ -48,7 +48,6 @@ unsigned long __init bootmem_init(unsigned long *pages_avail);
 #define PTRS_PER_PMD    	64
 #define PTRS_PER_PGD    	256
 #define USER_PTRS_PER_PGD	PAGE_OFFSET / PGDIR_SIZE
-#define FIRST_USER_ADDRESS	0UL
 #define PTE_SIZE		(PTRS_PER_PTE*4)
 
 #define PAGE_NONE	SRMMU_PAGE_NONE
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 550d3904de65..57460b7ada7b 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -95,9 +95,6 @@ bool kern_addr_valid(unsigned long addr);
 #define PTRS_PER_PUD	(1UL << PUD_BITS)
 #define PTRS_PER_PGD	(1UL << PGDIR_BITS)
 
-/* Kernel has a separate 44bit address space. */
-#define FIRST_USER_ADDRESS	0UL
-
 #define pmd_ERROR(e)							\
 	pr_err("%s:%d: bad pmd %p(%016lx) seen at (%pS)\n",		\
 	       __FILE__, __LINE__, &(e), pmd_val(e), __builtin_return_address(0))
diff --git a/arch/um/include/asm/pgtable-2level.h b/arch/um/include/asm/pgtable-2level.h
index 32106d31e4ab..8256ecc5b919 100644
--- a/arch/um/include/asm/pgtable-2level.h
+++ b/arch/um/include/asm/pgtable-2level.h
@@ -23,7 +23,6 @@
 #define PTRS_PER_PTE	1024
 #define USER_PTRS_PER_PGD ((TASK_SIZE + (PGDIR_SIZE - 1)) / PGDIR_SIZE)
 #define PTRS_PER_PGD	1024
-#define FIRST_USER_ADDRESS	0UL
 
 #define pte_ERROR(e) \
         printk("%s:%d: bad pte %p(%08lx).\n", __FILE__, __LINE__, &(e), \
diff --git a/arch/um/include/asm/pgtable-3level.h b/arch/um/include/asm/pgtable-3level.h
index 7e6a4180db9d..9289a86643a9 100644
--- a/arch/um/include/asm/pgtable-3level.h
+++ b/arch/um/include/asm/pgtable-3level.h
@@ -41,7 +41,6 @@
 #endif
 
 #define USER_PTRS_PER_PGD ((TASK_SIZE + (PGDIR_SIZE - 1)) / PGDIR_SIZE)
-#define FIRST_USER_ADDRESS	0UL
 
 #define pte_ERROR(e) \
         printk("%s:%d: bad pte %p(%016lx).\n", __FILE__, __LINE__, &(e), \
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index f24d7ef8fffa..40497a9020c6 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -7,8 +7,6 @@
 
 #include <asm/page_types.h>
 
-#define FIRST_USER_ADDRESS	0UL
-
 #define _PAGE_BIT_PRESENT	0	/* is present */
 #define _PAGE_BIT_RW		1	/* writeable */
 #define _PAGE_BIT_USER		2	/* userspace addressable */
diff --git a/arch/xtensa/include/asm/pgtable.h b/arch/xtensa/include/asm/pgtable.h
index 4dc04e6c01d7..38aa57e34390 100644
--- a/arch/xtensa/include/asm/pgtable.h
+++ b/arch/xtensa/include/asm/pgtable.h
@@ -59,7 +59,6 @@
 #define PTRS_PER_PGD		1024
 #define PGD_ORDER		0
 #define USER_PTRS_PER_PGD	(TASK_SIZE/PGDIR_SIZE)
-#define FIRST_USER_ADDRESS	0UL
 #define FIRST_USER_PGD_NR	(FIRST_USER_ADDRESS >> PGDIR_SHIFT)
 
 #ifdef CONFIG_MMU
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8ba434287387..47098ccd715e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -46,6 +46,10 @@ extern int sysctl_page_lock_unfairness;
 
 void init_mm_internals(void);
 
+#ifndef ARCH_HAS_FIRST_USER_ADDRESS
+#define FIRST_USER_ADDRESS	0UL
+#endif
+
 #ifndef CONFIG_NEED_MULTIPLE_NODES	/* Don't use mapnrs, do it properly */
 extern unsigned long max_mapnr;
 
diff --git a/mm/Kconfig b/mm/Kconfig
index 24c045b24b95..373fbe377075 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -806,6 +806,10 @@ config VMAP_PFN
 
 config ARCH_USES_HIGH_VMA_FLAGS
 	bool
+
+config ARCH_HAS_FIRST_USER_ADDRESS
+	bool
+
 config ARCH_HAS_PKEYS
 	bool
 
-- 
2.20.1