From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f42.google.com (mail-qg0-f42.google.com [209.85.192.42]) by kanga.kvack.org (Postfix) with ESMTP id C3B9A6B0254 for ; Mon, 17 Aug 2015 13:01:20 -0400 (EDT) Received: by qged69 with SMTP id d69so97760580qge.0 for ; Mon, 17 Aug 2015 10:01:20 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id x128si26068588qha.40.2015.08.17.10.01.18 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 17 Aug 2015 10:01:19 -0700 (PDT) From: Mark Salter Subject: [PATCH V4 1/3] mm: add utility for early copy from unmapped ram Date: Mon, 17 Aug 2015 13:01:05 -0400 Message-Id: <1439830867-14935-2-git-send-email-msalter@redhat.com> In-Reply-To: <1439830867-14935-1-git-send-email-msalter@redhat.com> References: <1439830867-14935-1-git-send-email-msalter@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Catalin Marinas , Will Deacon , x86@kernel.org Cc: Andrew Morton , Arnd Bergmann , Ard Biesheuvel , Mark Rutland , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, Mark Salter In some early boot circumstances, it may be necessary to copy from RAM outside the kernel linear mapping to mapped RAM. The need to relocate an initrd is one example in the x86 code. This patch creates a helper function based on current x86 code. Signed-off-by: Mark Salter --- include/asm-generic/early_ioremap.h | 6 ++++++ mm/early_ioremap.c | 22 ++++++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/include/asm-generic/early_ioremap.h b/include/asm-generic/early_ioremap.h index a5de55c..e539f27 100644 --- a/include/asm-generic/early_ioremap.h +++ b/include/asm-generic/early_ioremap.h @@ -33,6 +33,12 @@ extern void early_ioremap_setup(void); */ extern void early_ioremap_reset(void); +/* + * Early copy from unmapped memory to kernel mapped memory. + */ +extern void copy_from_early_mem(void *dest, phys_addr_t src, + unsigned long size); + #else static inline void early_ioremap_init(void) { } static inline void early_ioremap_setup(void) { } diff --git a/mm/early_ioremap.c b/mm/early_ioremap.c index e10ccd2..a0baeb4 100644 --- a/mm/early_ioremap.c +++ b/mm/early_ioremap.c @@ -217,6 +217,28 @@ early_memremap(resource_size_t phys_addr, unsigned long size) return (__force void *)__early_ioremap(phys_addr, size, FIXMAP_PAGE_NORMAL); } + +#define MAX_MAP_CHUNK (NR_FIX_BTMAPS << PAGE_SHIFT) + +void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size) +{ + unsigned long slop, clen; + char *p; + + while (size) { + slop = src & ~PAGE_MASK; + clen = size; + if (clen > MAX_MAP_CHUNK - slop) + clen = MAX_MAP_CHUNK - slop; + p = early_memremap(src & PAGE_MASK, clen + slop); + memcpy(dest, p + slop, clen); + early_memunmap(p, clen + slop); + dest += clen; + src += clen; + size -= clen; + } +} + #else /* CONFIG_MMU */ void __init __iomem * -- 2.4.3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org