From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Mon, 20 Sep 2004 16:40:49 +0100 (BST) Received: from p508B7085.dip.t-dialin.net ([IPv6:::ffff:80.139.112.133]:9318 "EHLO mail.linux-mips.net") by linux-mips.org with ESMTP id ; Mon, 20 Sep 2004 16:40:44 +0100 Received: from fluff.linux-mips.net (fluff.linux-mips.net [127.0.0.1]) by mail.linux-mips.net (8.12.11/8.12.8) with ESMTP id i8KFehA0014934; Mon, 20 Sep 2004 17:40:43 +0200 Received: (from ralf@localhost) by fluff.linux-mips.net (8.12.11/8.12.11/Submit) id i8KFegZL014933; Mon, 20 Sep 2004 17:40:42 +0200 Date: Mon, 20 Sep 2004 17:40:42 +0200 From: Ralf Baechle To: Richard Sandiford Cc: Atsushi Nemoto , linux-mips@linux-mips.org Subject: Re: gcc 3.3.4/3.4.1 and get_user Message-ID: <20040920154042.GB5150@linux-mips.org> References: <20040901.012223.59462025.anemo@mba.ocn.ne.jp> <87656yqsmz.fsf@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87656yqsmz.fsf@redhat.com> User-Agent: Mutt/1.4.1i Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 5862 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Wed, Sep 01, 2004 at 09:51:16AM +0100, Richard Sandiford wrote: > The latter. gcc is putting the empty asm: > > __asm__ ("":"=r" (__gu_val)); > > into the delay slot of the call. The purpose of this was to avoid a warning about __gu_val possibly being used uninitialized without inflating the code. I've got a better solution that'll actually shrinks the code size of my defconfig build by 5448 bytes. Untested patch below. Ralf Index: include/asm-mips/uaccess.h =================================================================== RCS file: /home/cvs/linux/include/asm-mips/uaccess.h,v retrieving revision 1.35 diff -u -r1.35 uaccess.h --- include/asm-mips/uaccess.h 19 Sep 2004 12:30:20 -0000 1.35 +++ include/asm-mips/uaccess.h 20 Sep 2004 12:33:27 -0000 @@ -225,88 +225,86 @@ * for 32 bit mode and old iron. */ #ifdef __mips64 -#define __GET_USER_DW __get_user_asm("ld") +#define __GET_USER_DW(__gu_err) __get_user_asm("ld", __gu_err) #else -#define __GET_USER_DW __get_user_asm_ll32 +#define __GET_USER_DW(__gu_err) __get_user_asm_ll32(__gu_err) #endif -#define __get_user_nocheck(x,ptr,size) \ -({ \ - long __gu_err; \ - __typeof(*(ptr)) __gu_val; \ - long __gu_addr; \ - might_sleep(); \ - __asm__("":"=r" (__gu_val)); \ - __gu_addr = (long) (ptr); \ - __asm__("":"=r" (__gu_err)); \ - switch (size) { \ - case 1: __get_user_asm("lb"); break; \ - case 2: __get_user_asm("lh"); break; \ - case 4: __get_user_asm("lw"); break; \ - case 8: __GET_USER_DW; break; \ - default: __get_user_unknown(); break; \ - } x = (__typeof__(*(ptr))) __gu_val; __gu_err; \ +#define __get_user_nocheck(x,ptr,size) \ +({ \ + long __gu_err = 0; \ + __typeof(*(ptr)) __gu_val = 0; \ + long __gu_addr; \ + might_sleep(); \ + __gu_addr = (long) (ptr); \ + switch (size) { \ + case 1: __get_user_asm("lb", __gu_err); break; \ + case 2: __get_user_asm("lh", __gu_err); break; \ + case 4: __get_user_asm("lw", __gu_err); break; \ + case 8: __GET_USER_DW(__gu_err); break; \ + default: __get_user_unknown(); break; \ + } \ + x = (__typeof__(*(ptr))) __gu_val; \ + __gu_err; \ }) #define __get_user_check(x,ptr,size) \ ({ \ - long __gu_err; \ - __typeof__(*(ptr)) __gu_val; \ + long __gu_err = 0; \ + __typeof__(*(ptr)) __gu_val = 0; \ long __gu_addr; \ might_sleep(); \ - __asm__("":"=r" (__gu_val)); \ __gu_addr = (long) (ptr); \ - __asm__("":"=r" (__gu_err)); \ if (access_ok(VERIFY_READ,__gu_addr,size)) { \ switch (size) { \ - case 1: __get_user_asm("lb"); break; \ - case 2: __get_user_asm("lh"); break; \ - case 4: __get_user_asm("lw"); break; \ - case 8: __GET_USER_DW; break; \ + case 1: __get_user_asm("lb", __gu_err); break; \ + case 2: __get_user_asm("lh", __gu_err); break; \ + case 4: __get_user_asm("lw", __gu_err); break; \ + case 8: __GET_USER_DW(__gu_err); break; \ default: __get_user_unknown(); break; \ } \ - } x = (__typeof__(*(ptr))) __gu_val; __gu_err; \ + } \ + x = (__typeof__(*(ptr))) __gu_val; \ + __gu_err; \ }) -#define __get_user_asm(insn) \ +#define __get_user_asm(insn,__gu_err) \ ({ \ __asm__ __volatile__( \ - "1:\t" insn "\t%1,%2\n\t" \ - "move\t%0,$0\n" \ - "2:\n\t" \ - ".section\t.fixup,\"ax\"\n" \ - "3:\tli\t%0,%3\n\t" \ - "move\t%1,$0\n\t" \ - "j\t2b\n\t" \ - ".previous\n\t" \ - ".section\t__ex_table,\"a\"\n\t" \ - __UA_ADDR "\t1b,3b\n\t" \ - ".previous" \ - :"=r" (__gu_err), "=r" (__gu_val) \ - :"o" (__m(__gu_addr)), "i" (-EFAULT)); \ + "1: " insn " %1, %3 \n" \ + "2: \n" \ + " .section .fixup,\"ax\" \n" \ + "3: li %0, %4 \n" \ + " j 2b \n" \ + " .previous \n" \ + " .section __ex_table,\"a\" \n" \ + " "__UA_ADDR "\t1b, 3b \n" \ + " .previous \n" \ + : "=r" (__gu_err), "=r" (__gu_val) \ + : "0" (__gu_err), "o" (__m(__gu_addr)), "i" (-EFAULT)); \ }) /* * Get a long long 64 using 32 bit registers. */ -#define __get_user_asm_ll32 \ +#define __get_user_asm_ll32(__gu_err) \ ({ \ __asm__ __volatile__( \ - "1:\tlw\t%1,%2\n" \ - "2:\tlw\t%D1,%3\n\t" \ - "move\t%0,$0\n" \ - "3:\t.section\t.fixup,\"ax\"\n" \ - "4:\tli\t%0,%4\n\t" \ - "move\t%1,$0\n\t" \ - "move\t%D1,$0\n\t" \ - "j\t3b\n\t" \ - ".previous\n\t" \ - ".section\t__ex_table,\"a\"\n\t" \ - __UA_ADDR "\t1b,4b\n\t" \ - __UA_ADDR "\t2b,4b\n\t" \ - ".previous" \ - :"=r" (__gu_err), "=&r" (__gu_val) \ - :"o" (__m(__gu_addr)), "o" (__m(__gu_addr + 4)), \ + "1: lw %1,%2 \n" \ + "2: lw %D1,%3 \n" \ + " move %0,$0 \n" \ + "3: .section .fixup,\"ax\" \n" \ + "4: li %0,%4 \n" \ + " move %1,$0 \n" \ + " move %D1,$0 \n" \ + " j 3b \n" \ + " .previous \n" \ + " .section __ex_table,\"a\" \n" \ + " " __UA_ADDR " 1b,4b \n" \ + " " __UA_ADDR " 2b,4b \n" \ + " .previous \n" \ + : "=r" (__gu_err), "=&r" (__gu_val) \ + : "o" (__m(__gu_addr)), "o" (__m(__gu_addr + 4)), \ "i" (-EFAULT)); \ }) @@ -317,25 +315,24 @@ * for 32 bit mode and old iron. */ #ifdef __mips64 -#define __PUT_USER_DW __put_user_asm("sd") +#define __PUT_USER_DW(__pu_val) __put_user_asm("sd", __pu_val) #else -#define __PUT_USER_DW __put_user_asm_ll32 +#define __PUT_USER_DW(__pu_val) __put_user_asm_ll32(__pu_val) #endif #define __put_user_nocheck(x,ptr,size) \ ({ \ - long __pu_err; \ + long __pu_err = 0; \ __typeof__(*(ptr)) __pu_val; \ long __pu_addr; \ might_sleep(); \ __pu_val = (x); \ __pu_addr = (long) (ptr); \ - __asm__("":"=r" (__pu_err)); \ switch (size) { \ - case 1: __put_user_asm("sb"); break; \ - case 2: __put_user_asm("sh"); break; \ - case 4: __put_user_asm("sw"); break; \ - case 8: __PUT_USER_DW; break; \ + case 1: __put_user_asm("sb", __pu_val); break; \ + case 2: __put_user_asm("sh", __pu_val); break; \ + case 4: __put_user_asm("sw", __pu_val); break; \ + case 8: __PUT_USER_DW(__pu_val); break; \ default: __put_user_unknown(); break; \ } \ __pu_err; \ @@ -343,57 +340,55 @@ #define __put_user_check(x,ptr,size) \ ({ \ - long __pu_err; \ + long __pu_err = 0; \ __typeof__(*(ptr)) __pu_val; \ long __pu_addr; \ might_sleep(); \ __pu_val = (x); \ __pu_addr = (long) (ptr); \ - __asm__("":"=r" (__pu_err)); \ if (access_ok(VERIFY_WRITE, __pu_addr, size)) { \ switch (size) { \ - case 1: __put_user_asm("sb"); break; \ - case 2: __put_user_asm("sh"); break; \ - case 4: __put_user_asm("sw"); break; \ - case 8: __PUT_USER_DW; break; \ + case 1: __put_user_asm("sb", __pu_val); break; \ + case 2: __put_user_asm("sh", __pu_val); break; \ + case 4: __put_user_asm("sw", __pu_val); break; \ + case 8: __PUT_USER_DW(__pu_val); break; \ default: __put_user_unknown(); break; \ } \ } \ __pu_err; \ }) -#define __put_user_asm(insn) \ +#define __put_user_asm(insn, __pu_val) \ ({ \ __asm__ __volatile__( \ - "1:\t" insn "\t%z1, %2\t\t\t# __put_user_asm\n\t" \ - "move\t%0, $0\n" \ - "2:\n\t" \ - ".section\t.fixup,\"ax\"\n" \ - "3:\tli\t%0,%3\n\t" \ - "j\t2b\n\t" \ - ".previous\n\t" \ - ".section\t__ex_table,\"a\"\n\t" \ - __UA_ADDR "\t1b,3b\n\t" \ - ".previous" \ + "1: " insn " %z1, %2 # __put_user_asm\n" \ + "2: \n" \ + " .section .fixup,\"ax\" \n" \ + "3: li %0,%3 \n" \ + " j 2b \n" \ + " .previous \n" \ + " .section __ex_table,\"a\" \n" \ + " " __UA_ADDR " 1b, 3b \n" \ + " .previous \n" \ :"=r" (__pu_err) \ :"Jr" (__pu_val), "o" (__m(__pu_addr)), "i" (-EFAULT)); \ }) -#define __put_user_asm_ll32 \ +#define __put_user_asm_ll32(__pu_val) \ ({ \ __asm__ __volatile__( \ - "1:\tsw\t%1, %2\t\t\t# __put_user_asm_ll32\n\t" \ - "2:\tsw\t%D1, %3\n" \ - "move\t%0, $0\n" \ - "3:\n\t" \ - ".section\t.fixup,\"ax\"\n" \ - "4:\tli\t%0,%4\n\t" \ - "j\t3b\n\t" \ - ".previous\n\t" \ - ".section\t__ex_table,\"a\"\n\t" \ - __UA_ADDR "\t1b,4b\n\t" \ - __UA_ADDR "\t2b,4b\n\t" \ - ".previous" \ + "1: sw %1, %2 # __put_user_asm_ll32 \n" \ + "2: sw %D1, %3 \n" \ + " move %0, $0 \n" \ + "3: \n" \ + " .section .fixup,\"ax\" \n" \ + "4: li %0, %4 \n" \ + " j 3b \n" \ + " .previous \n" \ + " .section __ex_table,\"a\" \n" \ + " " __UA_ADDR " 1b, 4b \n" \ + " " __UA_ADDR " 2b, 4b \n" \ + " .previous" \ :"=r" (__pu_err) \ :"r" (__pu_val), "o" (__m(__pu_addr)), \ "o" (__m(__pu_addr + 4)), "i" (-EFAULT)); \