From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takuya Yoshikawa Subject: [RFC][PATCH 4/12] x86: introduce copy_in_user() for 32-bit Date: Tue, 4 May 2010 22:02:09 +0900 Message-ID: <20100504220209.c3836ef3.takuya.yoshikawa@gmail.com> References: <20100504215645.6448af8f.takuya.yoshikawa@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mail-px0-f174.google.com ([209.85.212.174]:53584 "EHLO mail-px0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753330Ab0EDNCO (ORCPT ); Tue, 4 May 2010 09:02:14 -0400 In-Reply-To: <20100504215645.6448af8f.takuya.yoshikawa@gmail.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Takuya Yoshikawa Cc: avi@redhat.com, mtosatti@redhat.com, agraf@suse.de, yoshikawa.takuya@oss.ntt.co.jp, fernando@oss.ntt.co.jp, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, kvm-ia64@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, benh@kernel.crashing.org, paulus@samba.org, linuxppc-dev@ozlabs.org, arnd@arndb.de, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org During the work of KVM's dirty page logging optimization, we encountered the need of copy_in_user() for 32-bit x86 and ppc: these will be used for manipulating dirty bitmaps in user space. So we implement copy_in_user() for 32-bit with existing generic copy user helpers. Signed-off-by: Takuya Yoshikawa Signed-off-by: Fernando Luis Vazquez Cao CC: Avi Kivity Cc: Thomas Gleixner CC: Ingo Molnar Cc: "H. Peter Anvin" --- arch/x86/include/asm/uaccess_32.h | 2 ++ arch/x86/lib/usercopy_32.c | 26 ++++++++++++++++++++++++++ 2 files changed, 28 insertions(+), 0 deletions(-) diff --git a/arch/x86/include/asm/uaccess_32.h b/arch/x86/include/asm/uaccess_32.h index 088d09f..85d396d 100644 --- a/arch/x86/include/asm/uaccess_32.h +++ b/arch/x86/include/asm/uaccess_32.h @@ -21,6 +21,8 @@ unsigned long __must_check __copy_from_user_ll_nocache (void *to, const void __user *from, unsigned long n); unsigned long __must_check __copy_from_user_ll_nocache_nozero (void *to, const void __user *from, unsigned long n); +unsigned long __must_check copy_in_user + (void __user *to, const void __user *from, unsigned n); /** * __copy_to_user_inatomic: - Copy a block of data into user space, with less checking. diff --git a/arch/x86/lib/usercopy_32.c b/arch/x86/lib/usercopy_32.c index e218d5d..e90ffc3 100644 --- a/arch/x86/lib/usercopy_32.c +++ b/arch/x86/lib/usercopy_32.c @@ -889,3 +889,29 @@ void copy_from_user_overflow(void) WARN(1, "Buffer overflow detected!\n"); } EXPORT_SYMBOL(copy_from_user_overflow); + +/** + * copy_in_user: - Copy a block of data from user space to user space. + * @to: Destination address, in user space. + * @from: Source address, in user space. + * @n: Number of bytes to copy. + * + * Context: User context only. This function may sleep. + * + * Copy data from user space to user space. + * + * Returns number of bytes that could not be copied. + * On success, this will be zero. + */ +unsigned long +copy_in_user(void __user *to, const void __user *from, unsigned n) +{ + if (access_ok(VERIFY_WRITE, to, n) && access_ok(VERIFY_READ, from, n)) { + if (movsl_is_ok(to, from, n)) + __copy_user(to, from, n); + else + n = __copy_user_intel(to, (const void *)from, n); + } + return n; +} +EXPORT_SYMBOL(copy_in_user); -- 1.7.0.4