From: "Amit K. Arora" Subject: Re: [PATCH 2/5][TAKE2] fallocate() on s390 - glibc wrapper Date: Mon, 14 May 2007 21:03:30 +0530 Message-ID: <20070514153330.GA25249@amitarora.in.ibm.com> References: <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> <20070514144833.GB31748@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 e32.co.us.ibm.com ([32.97.110.150]:54370 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754207AbXENPdc (ORCPT ); Mon, 14 May 2007 11:33:32 -0400 Content-Disposition: inline In-Reply-To: <20070514144833.GB31748@amitarora.in.ibm.com> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Mon, May 14, 2007 at 08:18:34PM +0530, Amit K. Arora wrote: > This is the patch suggested by Martin Schwidefsky. Here are the comments > and patch from him. Martin also suggested a wrapper in glibc to handle this system call on s390. Posting it here so that we get feedback for this too. Here it is: .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) -- Regards, Amit Arora > ------------- > 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 > - > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html