From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55862) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fDf61-0000iP-Go for qemu-devel@nongnu.org; Tue, 01 May 2018 19:54:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fDf5w-0002gV-HF for qemu-devel@nongnu.org; Tue, 01 May 2018 19:54:09 -0400 Received: from mout.kundenserver.de ([212.227.126.130]:56867) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1fDf5w-0002ei-6Q for qemu-devel@nongnu.org; Tue, 01 May 2018 19:54:04 -0400 From: Laurent Vivier Date: Wed, 2 May 2018 01:53:32 +0200 Message-Id: <20180501235332.31245-1-laurent@vivier.eu> Subject: [Qemu-devel] [PATCH] linux-user: remove useless padding in flock64 structure List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Riku Voipio , Laurent Vivier Since commit 8efb2ed5ec ("linux-user: Correct signedness of target_flock l_start and l_len fields"), flock64 structure uses abi_llong for l_start and l_len in place of "unsigned long long" this should force them to be aligned accordingly to the target rules. So we can remove the padding field and the QEMU_PACKED attribute. I have compared the result of the following program before and after the change: cat -> flock64_dump <l_type p/d &((struct target_flock64 *)0)->l_whence p/d &((struct target_flock64 *)0)->l_start p/d &((struct target_flock64 *)0)->l_len p/d &((struct target_flock64 *)0)->l_pid quit EOF for file in build/all/*-linux-user/qemu-* ; do echo $file gdb -batch -nx -x flock64_dump $file 2> /dev/null done The sizeof() changes because we remove the QEMU_PACKED. The new size is 32 (except for i386 and m68k) and this is the real size of "struct flock64" on the target architecture. The following architectures differ: aarch64_be, aarch64, alpha, armeb, arm, cris, hppa, nios2, or1k, riscv32, riscv64, s390x. For a subset of these architectures, I have checked with the following program the new structure is the correct one: #include #define __USE_LARGEFILE64 #include int main(void) { printf("struct flock64 %d\n", sizeof(struct flock64)); printf("l_type %d\n", &((struct flock64 *)0)->l_type); printf("l_whence %d\n", &((struct flock64 *)0)->l_whence); printf("l_start %d\n", &((struct flock64 *)0)->l_start); printf("l_len %d\n", &((struct flock64 *)0)->l_len); printf("l_pid %d\n", &((struct flock64 *)0)->l_pid); } [I have checked aarch64, alpha, arm, s390x] I have also fixed the alignment value for sh4 (to align llong on 4 bytes) (see c2e3dee6e0 "linux-user: Define target alignment size") Signed-off-by: Laurent Vivier --- include/exec/user/abitypes.h | 2 +- linux-user/syscall_defs.h | 23 ++++++++--------------- 2 files changed, 9 insertions(+), 16 deletions(-) diff --git a/include/exec/user/abitypes.h b/include/exec/user/abitypes.h index ba188608c2..743b8bb9ea 100644 --- a/include/exec/user/abitypes.h +++ b/include/exec/user/abitypes.h @@ -15,7 +15,7 @@ #define ABI_LLONG_ALIGNMENT 2 #endif -#if defined(TARGET_I386) && !defined(TARGET_X86_64) +#if (defined(TARGET_I386) && !defined(TARGET_X86_64)) || defined(TARGET_SH4) #define ABI_LLONG_ALIGNMENT 4 #endif diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h index 23f5bccf0e..df3847bc16 100644 --- a/linux-user/syscall_defs.h +++ b/linux-user/syscall_defs.h @@ -2649,28 +2649,21 @@ struct target_flock { }; struct target_flock64 { - short l_type; - short l_whence; -#if defined(TARGET_PPC) || defined(TARGET_X86_64) || defined(TARGET_MIPS) \ - || defined(TARGET_SPARC) || defined(TARGET_HPPA) \ - || defined(TARGET_MICROBLAZE) || defined(TARGET_TILEGX) \ - || defined(TARGET_XTENSA) - int __pad; -#endif + abi_short l_type; + abi_short l_whence; abi_llong l_start; abi_llong l_len; - int l_pid; -} QEMU_PACKED; + abi_int l_pid; +}; #ifdef TARGET_ARM struct target_eabi_flock64 { - short l_type; - short l_whence; - int __pad; + abi_short l_type; + abi_short l_whence; abi_llong l_start; abi_llong l_len; - int l_pid; -} QEMU_PACKED; + abi_int l_pid; +}; #endif struct target_f_owner_ex { -- 2.14.3