From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f71.google.com (mail-pl0-f71.google.com [209.85.160.71]) by kanga.kvack.org (Postfix) with ESMTP id 655936B05AD for ; Wed, 9 May 2018 21:44:51 -0400 (EDT) Received: by mail-pl0-f71.google.com with SMTP id p19-v6so332954plo.14 for ; Wed, 09 May 2018 18:44:51 -0700 (PDT) Received: from mail.kernel.org (mail.kernel.org. [198.145.29.99]) by mx.google.com with ESMTPS id d20si13146550pfn.213.2018.05.09.18.44.50 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 09 May 2018 18:44:50 -0700 (PDT) From: "Luis R. Rodriguez" Subject: [PATCH v2 1/2] mm: provide a fallback for PAGE_KERNEL_RO for architectures Date: Wed, 9 May 2018 18:44:46 -0700 Message-Id: <20180510014447.15989-2-mcgrof@kernel.org> In-Reply-To: <20180510014447.15989-1-mcgrof@kernel.org> References: <20180510014447.15989-1-mcgrof@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: arnd@arndb.de Cc: gregkh@linuxfoundation.org, willy@infradead.org, geert@linux-m68k.org, linux-m68k@lists.linux-m68k.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Luis R. Rodriguez" Some architectures do not define certain PAGE_KERNEL_* flags, this is either because: a) The way to implement some these flags is *not yet ported*, or b) The architecture *has no way* to describe them Over time we have accumulated a few PAGE_KERNEL_* fallback work arounds for architectures in the kernel which do not define them using *relatively safe* equivalents. Move these scattered fallback hacks into asm-generic and document which architectures needs further evaluation for which PAGE_KERNEL_* flag. We start off with PAGE_KERNEL_RO using PAGE_KERNEL as a fallback. This has been in place on the firmware loader for years. Move the fallback into the respective asm-generic header. Architectures which don't define this yet: o alpha o ia64 o m68k o mips o sparc64 o sparc Signed-off-by: Luis R. Rodriguez --- drivers/base/firmware_loader/fallback.c | 5 ----- include/asm-generic/pgtable.h | 24 ++++++++++++++++++++++++ 2 files changed, 24 insertions(+), 5 deletions(-) diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c index 358354148dec..36f016b753e0 100644 --- a/drivers/base/firmware_loader/fallback.c +++ b/drivers/base/firmware_loader/fallback.c @@ -219,11 +219,6 @@ static ssize_t firmware_loading_show(struct device *dev, return sprintf(buf, "%d\n", loading); } -/* Some architectures don't have PAGE_KERNEL_RO */ -#ifndef PAGE_KERNEL_RO -#define PAGE_KERNEL_RO PAGE_KERNEL -#endif - /* one pages buffer should be mapped/unmapped only once */ static int map_fw_priv_pages(struct fw_priv *fw_priv) { diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index f59639afaa39..890fc54f4713 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -1083,6 +1083,30 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, static inline void init_espfix_bsp(void) { } #endif +/* + * Architecture PAGE_KERNEL_* fallbacks + * + * Some architectures don't define certain PAGE_KERNEL_* flags. This is either + * because they really don't support them, or the port needs to be updated to + * reflect the required functionality. Below are a set of relatively safe + * fallbacks, as best effort, which we can count on in lieu of the architectures + * not defining them on their own yet. + */ + +/* + * Current architectures known to not define PAGE_KERNEL_RO: + * + * o alpha + * o ia64 + * o m68k + * o mips + * o sparc64 + * o sparc + */ +#ifndef PAGE_KERNEL_RO +# define PAGE_KERNEL_RO PAGE_KERNEL +#endif + #endif /* !__ASSEMBLY__ */ #ifndef io_remap_pfn_range -- 2.17.0