From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: [patch 91/93] x86: use non-set_fs based maccess routines Date: Mon, 08 Jun 2020 21:35:01 -0700 Message-ID: <20200609043501.zcGYY277G%akpm@linux-foundation.org> References: <20200608212922.5b7fa74ca3f4e2444441b7f9@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:59170 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725772AbgFIEfD (ORCPT ); Tue, 9 Jun 2020 00:35:03 -0400 In-Reply-To: <20200608212922.5b7fa74ca3f4e2444441b7f9@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: akpm@linux-foundation.org, ast@kernel.org, daniel@iogearbox.net, hch@lst.de, hpa@zytor.com, linux-mm@kvack.org, mhiramat@kernel.org, mingo@elte.hu, mm-commits@vger.kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org From: Christoph Hellwig Subject: x86: use non-set_fs based maccess routines Provide arch_kernel_read and arch_kernel_write routines to implement the maccess routines without messing with set_fs and without stac/clac that opens up access to user space. [akpm@linux-foundation.org: coding style fixes] Link: http://lkml.kernel.org/r/20200521152301.2587579-20-hch@lst.de Signed-off-by: Christoph Hellwig Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Masami Hiramatsu Cc: Thomas Gleixner Signed-off-by: Andrew Morton --- arch/x86/include/asm/uaccess.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) --- a/arch/x86/include/asm/uaccess.h~x86-use-non-set_fs-based-maccess-routines +++ a/arch/x86/include/asm/uaccess.h @@ -523,5 +523,21 @@ do { \ unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u8, label); \ } while (0) +#define HAVE_GET_KERNEL_NOFAULT + +#define __get_kernel_nofault(dst, src, type, err_label) \ +do { \ + int __kr_err; \ + \ + __get_user_size(*((type *)dst), (__force type __user *)src, \ + sizeof(type), __kr_err); \ + if (unlikely(__kr_err)) \ + goto err_label; \ +} while (0) + +#define __put_kernel_nofault(dst, src, type, err_label) \ + __put_user_size(*((type *)(src)), (__force type __user *)(dst), \ + sizeof(type), err_label) + #endif /* _ASM_X86_UACCESS_H */ _