From: "Amit K. Arora" Subject: [PATCH 2/5][TAKE2] fallocate() on s390 Date: Mon, 14 May 2007 20:18:34 +0530 Message-ID: <20070514144833.GB31748@amitarora.in.ibm.com> References: <20070329101010.7a2b8783.akpm@linux-foundation.org> <20070330071417.GI355@devserv.devel.redhat.com> <20070417125514.GA7574@amitarora.in.ibm.com> <20070418130600.GW5967@schatzie.adilger.int> <20070420135146.GA21352@amitarora.in.ibm.com> <20070420145918.GY355@devserv.devel.redhat.com> <20070424121632.GA10136@amitarora.in.ibm.com> <20070426175056.GA25321@amitarora.in.ibm.com> <20070514132926.GA30768@amitarora.in.ibm.com> <20070514142820.GA31468@amitarora.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, xfs@oss.sgi.com, suparna@in.ibm.com, cmm@us.ibm.com To: torvalds@osdl.org, akpm@linux-foundation.org Return-path: Received: from e4.ny.us.ibm.com ([32.97.182.144]:45569 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754450AbXENOs0 (ORCPT ); Mon, 14 May 2007 10:48:26 -0400 Content-Disposition: inline In-Reply-To: <20070514142820.GA31468@amitarora.in.ibm.com> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org This is the patch suggested by Martin Schwidefsky. Here are the comments and patch from him. ------------- From: Martin Schwidefsky This patch implements support of fallocate system call on s390(x) platform. A wrapper is added to address the issue which s390 ABI has with the arguments of this system call. Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/compat_wrapper.S | 10 ++++++++++ arch/s390/kernel/sys_s390.c | 29 +++++++++++++++++++++++++++++ arch/s390/kernel/syscalls.S | 1 + include/asm-s390/unistd.h | 3 ++- 4 files changed, 42 insertions(+), 1 deletion(-) Index: linux-2.6.21/arch/s390/kernel/compat_wrapper.S =================================================================== --- linux-2.6.21.orig/arch/s390/kernel/compat_wrapper.S +++ linux-2.6.21/arch/s390/kernel/compat_wrapper.S @@ -1682,3 +1682,13 @@ compat_sys_utimes_wrapper: llgtr %r2,%r2 # char * llgtr %r3,%r3 # struct compat_timeval * jg compat_sys_utimes + + .globl sys_fallocate_wrapper +sys_fallocate_wrapper: + lgfr %r2,%r2 # int + lgfr %r3,%r3 # int + sllg %r4,%r4,32 # get high word of 64bit loff_t + lr %r4,%r5 # get low word of 64bit loff_t + sllg %r5,%r6,32 # get high word of 64bit loff_t + l %r5,164(%r15) # get low word of 64bit loff_t + jg sys_fallocate Index: linux-2.6.21/arch/s390/kernel/syscalls.S =================================================================== --- linux-2.6.21.orig/arch/s390/kernel/syscalls.S +++ linux-2.6.21/arch/s390/kernel/syscalls.S @@ -322,3 +322,4 @@ NI_SYSCALL /* 310 sys_move_pages * SYSCALL(sys_getcpu,sys_getcpu,sys_getcpu_wrapper) SYSCALL(sys_epoll_pwait,sys_epoll_pwait,compat_sys_epoll_pwait_wrapper) SYSCALL(sys_utimes,sys_utimes,compat_sys_utimes_wrapper) +SYSCALL(s390_fallocate,sys_fallocate,sys_fallocate_wrapper) Index: linux-2.6.21/arch/s390/kernel/sys_s390.c =================================================================== --- linux-2.6.21.orig/arch/s390/kernel/sys_s390.c +++ linux-2.6.21/arch/s390/kernel/sys_s390.c @@ -286,3 +286,32 @@ int kernel_execve(const char *filename, "d" (__arg3) : "memory"); return __svcres; } + +#ifndef CONFIG_64BIT +/* + * This is a wrapper to call sys_fallocate(). For 31 bit s390 the last + * 64 bit argument "len" is split into the upper and lower 32 bits. The + * system call wrapper in the user space loads the value to %r6/%r7. + * The code in entry.S keeps the values in %r2 - %r6 where they are and + * stores %r7 to 96(%r15). But the standard C linkage requires that + * the whole 64 bit value for len is stored on the stack and doesn't + * use %r6 at all. So s390_fallocate has to convert the arguments from + * %r2: fd, %r3: mode, %r4/%r5: offset, %r6/96(%r15)-99(%r15): len + * to + * %r2: fd, %r3: mode, %r4/%r5: offset, 96(%r15)-103(%r15): len + */ +asmlinkage long s390_fallocate(int fd, int mode, loff_t offset, + u32 len_high, u32 len_low) +{ + union { + u64 len; + struct { + u32 high; + u32 low; + }; + } cv; + cv.high = len_high; + cv.low = len_low; + return sys_fallocate(fd, mode, offset, cv.len); +} +#endif Index: linux-2.6.21/include/asm-s390/unistd.h =================================================================== --- linux-2.6.21.orig/include/asm-s390/unistd.h +++ linux-2.6.21/include/asm-s390/unistd.h @@ -251,8 +251,9 @@ #define __NR_getcpu 311 #define __NR_epoll_pwait 312 #define __NR_utimes 313 +#define __NR_fallocate 314 -#define NR_syscalls 314 +#define NR_syscalls 315 /* * There are some system calls that are not present on 64 bit, some