From: "Amit K. Arora" Subject: [PATCH 2/7][TAKE5] fallocate() on s390(x) Date: Mon, 25 Jun 2007 19:12:55 +0530 Message-ID: <20070625134255.GC1951@amitarora.in.ibm.com> References: <20070510115620.GB21400@amitarora.in.ibm.com> <20070510223950.GD86004887@sgi.com> <20070511110301.GB28425@in.ibm.com> <20070512080157.GF85884050@sgi.com> <20070612061652.GA6320@amitarora.in.ibm.com> <20070613235217.GS86004887@sgi.com> <20070614091458.GH5181@schatzie.adilger.int> <20070614120413.GD86004887@sgi.com> <20070614193347.GN5181@schatzie.adilger.int> <20070625132810.GA1951@amitarora.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Chinner , Andreas Dilger , suparna@in.ibm.com, cmm@us.ibm.com, xfs@oss.sgi.com To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org Return-path: Content-Disposition: inline In-Reply-To: <20070625132810.GA1951@amitarora.in.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org This is the patch suggested by Martin Schwidefsky to support sys_fallocate() on s390(x) platform. He also suggested a wrapper in glibc to handle this system call on s390. Posting it here so that we get feedback for this too. .globl __fallocate ENTRY(__fallocate) stm %r6,%r7,28(%r15) /* save %r6/%r7 on stack */ cfi_offset (%r7, -68) cfi_offset (%r6, -72) lm %r6,%r7,96(%r15) /* load loff_t len from stack */ svc SYS_ify(fallocate) lm %r6,%r7,28(%r15) /* restore %r6/%r7 from stack */ br %r14 PSEUDO_END(__fallocate) Here are the comments and the patch to linux kernel 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 Index: linux-2.6.22-rc4/arch/s390/kernel/compat_wrapper.S =================================================================== --- linux-2.6.22-rc4.orig/arch/s390/kernel/compat_wrapper.S 2007-06-11 16:16:01.000000000 -0700 +++ linux-2.6.22-rc4/arch/s390/kernel/compat_wrapper.S 2007-06-11 16:27:29.000000000 -0700 @@ -1683,6 +1683,16 @@ 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 + .globl compat_sys_utimensat_wrapper compat_sys_utimensat_wrapper: llgfr %r2,%r2 # unsigned int Index: linux-2.6.22-rc4/arch/s390/kernel/sys_s390.c =================================================================== --- linux-2.6.22-rc4.orig/arch/s390/kernel/sys_s390.c 2007-06-11 16:16:01.000000000 -0700 +++ linux-2.6.22-rc4/arch/s390/kernel/sys_s390.c 2007-06-11 16:27:29.000000000 -0700 @@ -265,3 +265,32 @@ return -EFAULT; return sys_fadvise64_64(a.fd, a.offset, a.len, a.advice); } + +#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-2.6.22-rc4/arch/s390/kernel/syscalls.S =================================================================== --- linux-2.6.22-rc4.orig/arch/s390/kernel/syscalls.S 2007-06-11 16:16:01.000000000 -0700 +++ linux-2.6.22-rc4/arch/s390/kernel/syscalls.S 2007-06-11 16:27:29.000000000 -0700 @@ -322,6 +322,7 @@ 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) NI_SYSCALL /* 314 sys_fallocate */ SYSCALL(sys_utimensat,sys_utimensat,compat_sys_utimensat_wrapper) /* 315 */ SYSCALL(sys_signalfd,sys_signalfd,compat_sys_signalfd_wrapper) Index: linux-2.6.22-rc4/include/asm-s390/unistd.h =================================================================== --- linux-2.6.22-rc4.orig/include/asm-s390/unistd.h 2007-06-11 16:16:01.000000000 -0700 +++ linux-2.6.22-rc4/include/asm-s390/unistd.h 2007-06-11 16:27:29.000000000 -0700 @@ -256,7 +256,8 @@ #define __NR_signalfd 316 #define __NR_timerfd 317 #define __NR_eventfd 318 -#define NR_syscalls 319 +#define __NR_fallocate 319 +#define NR_syscalls 320 /* * There are some system calls that are not present on 64 bit, some