From patchwork Mon May 10 03:02:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anshuman Khandual X-Patchwork-Id: 12246695 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 783A3C433ED for ; Mon, 10 May 2021 03:01:53 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DAEE560FD9 for ; Mon, 10 May 2021 03:01:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DAEE560FD9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 3E7416B0070; Sun, 9 May 2021 23:01:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 397C36B0071; Sun, 9 May 2021 23:01:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1C0916B0072; Sun, 9 May 2021 23:01:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0173.hostedemail.com [216.40.44.173]) by kanga.kvack.org (Postfix) with ESMTP id E30C26B0070 for ; Sun, 9 May 2021 23:01:51 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 8FBE0180AD81D for ; Mon, 10 May 2021 03:01:51 +0000 (UTC) X-FDA: 78123821622.20.C41E014 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf22.hostedemail.com (Postfix) with ESMTP id 0497CC0001EA for ; Mon, 10 May 2021 03:01:42 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9EE25ED1; Sun, 9 May 2021 20:01:49 -0700 (PDT) Received: from p8cg001049571a15.arm.com (unknown [10.163.77.48]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 594BF3F718; Sun, 9 May 2021 20:01:41 -0700 (PDT) From: Anshuman Khandual To: linux-mm@kvack.org, akpm@linux-foundation.org Cc: Anshuman Khandual , Richard Henderson , Vineet Gupta , Catalin Marinas , Will Deacon , Guo Ren , Brian Cain , Geert Uytterhoeven , Michal Simek , Thomas Bogendoerfer , Ley Foon Tan , Jonas Bonn , Stefan Kristiansson , Stafford Horne , "James E.J. Bottomley" , Michael Ellerman , Christophe Leroy , Paul Walmsley , Palmer Dabbelt , Heiko Carstens , Yoshinori Sato , "David S. Miller" , Jeff Dike , Thomas Gleixner , Chris Zankel , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH V2 RESEND] mm: Define default value for FIRST_USER_ADDRESS Date: Mon, 10 May 2021 08:32:05 +0530 Message-Id: <1620615725-24623-1-git-send-email-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.7.4 Authentication-Results: imf22.hostedemail.com; dkim=none; spf=pass (imf22.hostedemail.com: domain of anshuman.khandual@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com; dmarc=pass (policy=none) header.from=arm.com X-Stat-Signature: b76uajajx76wataq3g5bjkfkcguueghb X-Rspamd-Queue-Id: 0497CC0001EA X-Rspamd-Server: rspam05 Received-SPF: none (arm.com>: No applicable sender policy available) receiver=imf22; identity=mailfrom; envelope-from=""; helo=foss.arm.com; client-ip=217.140.110.172 X-HE-DKIM-Result: none/none X-HE-Tag: 1620615702-541717 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Currently most platforms define FIRST_USER_ADDRESS as 0UL duplication the same code all over. Instead just define a generic default value (i.e 0UL) for FIRST_USER_ADDRESS and let the platforms override when required. This makes it much cleaner with reduced code. The default FIRST_USER_ADDRESS here would be skipped in when the given platform overrides its value via . Cc: Richard Henderson Cc: Vineet Gupta Cc: Catalin Marinas Cc: Will Deacon Cc: Guo Ren Cc: Brian Cain Cc: Geert Uytterhoeven Cc: Michal Simek Cc: Thomas Bogendoerfer Cc: Ley Foon Tan Cc: Jonas Bonn Cc: Stefan Kristiansson Cc: Stafford Horne Cc: "James E.J. Bottomley" Cc: Michael Ellerman Cc: Christophe Leroy Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Heiko Carstens Cc: Yoshinori Sato Cc: "David S. Miller" Cc: Jeff Dike Cc: Thomas Gleixner Cc: Chris Zankel Cc: Andrew Morton Cc: linux-arch@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Acked-by: Geert Uytterhoeven #m68k Acked-by: Guo Ren #csky Acked-by: Stafford Horne #openrisc Acked-by: Catalin Marinas #arm64 Acked-by: Mike Rapoport Signed-off-by: Anshuman Khandual Acked-by: Palmer Dabbelt # RISC-V --- This applies on v5.13-rc1 and has been boot tested on arm64 platform. But has been cross compiled on multiple other platforms. Changes in V2: - Dropped ARCH_HAS_FIRST_USER_ADDRESS construct Changes in V1: https://patchwork.kernel.org/project/linux-mm/patch/1618368899-20311-1-git-send-email-anshuman.khandual@arm.com/ arch/alpha/include/asm/pgtable.h | 1 - arch/arc/include/asm/pgtable.h | 6 ------ 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/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/pgtable.h | 9 +++++++++ 26 files changed, 9 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/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 0b10204e72fc..25f5c04b43ce 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 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 d765fd948fae..3f5dbbd8b9d8 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 #include -#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/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 #include -#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 #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 57cd3892bfe0..53fbfdfac93d 100644 --- a/arch/powerpc/include/asm/nohash/64/pgtable.h +++ b/arch/powerpc/include/asm/nohash/64/pgtable.h @@ -12,8 +12,6 @@ #include #include -#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 9469f464e71a..286870765b49 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -537,8 +537,6 @@ 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 a5cf79c149fe..0888bda245f5 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 -#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 d7fc45c920c2..bd5aeb795567 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/pgtable.h b/include/linux/pgtable.h index 46b13780c2c8..1bed8b82e59d 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -28,6 +28,15 @@ #define USER_PGTABLES_CEILING 0UL #endif +/* + * This defines the first usable user address. Platforms + * can override its value with custom FIRST_USER_ADDRESS + * defined in their respective . + */ +#ifndef FIRST_USER_ADDRESS +#define FIRST_USER_ADDRESS 0UL +#endif + /* * A page table page can be thought of an array like this: pXd_t[PTRS_PER_PxD] *