From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f70.google.com (mail-oi0-f70.google.com [209.85.218.70]) by kanga.kvack.org (Postfix) with ESMTP id 5F6CB8E0006 for ; Wed, 12 Sep 2018 06:26:04 -0400 (EDT) Received: by mail-oi0-f70.google.com with SMTP id j17-v6so1744188oii.8 for ; Wed, 12 Sep 2018 03:26:04 -0700 (PDT) Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id t145-v6si437785oih.243.2018.09.12.03.26.02 for ; Wed, 12 Sep 2018 03:26:02 -0700 (PDT) From: Will Deacon Subject: [PATCH 4/5] lib/ioremap: Ensure phys_addr actually corresponds to a physical address Date: Wed, 12 Sep 2018 11:26:13 +0100 Message-Id: <1536747974-25875-5-git-send-email-will.deacon@arm.com> In-Reply-To: <1536747974-25875-1-git-send-email-will.deacon@arm.com> References: <1536747974-25875-1-git-send-email-will.deacon@arm.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: cpandya@codeaurora.org, toshi.kani@hpe.com, tglx@linutronix.de, mhocko@suse.com, akpm@linux-foundation.org, Will Deacon The current ioremap() code uses a phys_addr variable at each level of page table, which is confusingly offset by subtracting the base virtual address being mapped so that adding the current virtual address back on when iterating through the page table entries gives back the corresponding physical address. This is fairly confusing and results in all users of phys_addr having to add the current virtual address back on. Instead, this patch just updates phys_addr when iterating over the page table entries, ensuring that it's always up-to-date and doesn't require explicit offsetting. Cc: Chintan Pandya Cc: Toshi Kani Cc: Thomas Gleixner Cc: Michal Hocko Cc: Andrew Morton Signed-off-by: Will Deacon --- lib/ioremap.c | 28 ++++++++++++---------------- 1 file changed, 12 insertions(+), 16 deletions(-) diff --git a/lib/ioremap.c b/lib/ioremap.c index 6c72764af19c..fc834a59c90c 100644 --- a/lib/ioremap.c +++ b/lib/ioremap.c @@ -101,19 +101,18 @@ static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr, pmd_t *pmd; unsigned long next; - phys_addr -= addr; pmd = pmd_alloc(&init_mm, pud, addr); if (!pmd) return -ENOMEM; do { next = pmd_addr_end(addr, end); - if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr + addr, prot)) + if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr, prot)) continue; - if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, prot)) + if (ioremap_pte_range(pmd, addr, next, phys_addr, prot)) return -ENOMEM; - } while (pmd++, addr = next, addr != end); + } while (pmd++, addr = next, phys_addr += PMD_SIZE, addr != end); return 0; } @@ -142,19 +141,18 @@ static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr, pud_t *pud; unsigned long next; - phys_addr -= addr; pud = pud_alloc(&init_mm, p4d, addr); if (!pud) return -ENOMEM; do { next = pud_addr_end(addr, end); - if (ioremap_try_huge_pud(pud, addr, next, phys_addr + addr, prot)) + if (ioremap_try_huge_pud(pud, addr, next, phys_addr, prot)) continue; - if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, prot)) + if (ioremap_pmd_range(pud, addr, next, phys_addr, prot)) return -ENOMEM; - } while (pud++, addr = next, addr != end); + } while (pud++, addr = next, phys_addr += PUD_SIZE, addr != end); return 0; } @@ -164,7 +162,6 @@ static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr, p4d_t *p4d; unsigned long next; - phys_addr -= addr; p4d = p4d_alloc(&init_mm, pgd, addr); if (!p4d) return -ENOMEM; @@ -173,14 +170,14 @@ static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr, if (ioremap_p4d_enabled() && ((next - addr) == P4D_SIZE) && - IS_ALIGNED(phys_addr + addr, P4D_SIZE)) { - if (p4d_set_huge(p4d, phys_addr + addr, prot)) + IS_ALIGNED(phys_addr, P4D_SIZE)) { + if (p4d_set_huge(p4d, phys_addr, prot)) continue; } - if (ioremap_pud_range(p4d, addr, next, phys_addr + addr, prot)) + if (ioremap_pud_range(p4d, addr, next, phys_addr, prot)) return -ENOMEM; - } while (p4d++, addr = next, addr != end); + } while (p4d++, addr = next, phys_addr += P4D_SIZE, addr != end); return 0; } @@ -196,14 +193,13 @@ int ioremap_page_range(unsigned long addr, BUG_ON(addr >= end); start = addr; - phys_addr -= addr; pgd = pgd_offset_k(addr); do { next = pgd_addr_end(addr, end); - err = ioremap_p4d_range(pgd, addr, next, phys_addr+addr, prot); + err = ioremap_p4d_range(pgd, addr, next, phys_addr, prot); if (err) break; - } while (pgd++, addr = next, addr != end); + } while (pgd++, addr = next, phys_addr += PGDIR_SIZE, addr != end); flush_cache_vmap(start, end); -- 2.1.4