Yes, we could replace TARGET_NR_fadvise64 with TARGET_NR_fadvise64_64 in Mips32 syscall numbers definition list, and expect the same effect. I just prefer to leave original symbols for syscall numbers, as they are defined in kernel headers, unless there is a compelling reason not to do it.
But, there is more. Code that handles TARGET_NR_fadvise64_64 in Qemu utilizes host's posix_advise(). It looks to me that this is just plain incorrect. It won't work correctly on 32 bit hosts, with respect to arguments of posix_advise() that are 32-bit (while 64-bit value is passed to them) Instead, posix_fadvise64() should have been used, IMHO. Please let me know if you think I should do anything additionally in relation to this matter. Thanks again! Aleksandar ______________________________________ From: Qemu-devel [qemu-devel-bounces+aleksandar.markovic=imgtec....@nongnu.org] on behalf of Aleksandar Markovic [aleksandar.marko...@imgtec.com] Sent: Tuesday, October 04, 2016 1:58 PM To: Peter Maydell; Aleksandar Markovic Cc: Riku Voipio; QEMU Developers; Laurent Vivier; Miodrag Dinic; Aleksandar Rikalo; Petar Jovanovic; Yongbok Kim; Leon Alrae; Aurelien Jarno Subject: Re: [Qemu-devel] [PATCH 4/4] linux-user: Fix fadvise64() syscall support for Mips32 Hi, Peter, The file in question is arch/mips/kernel/scall32-o32.S. I'll correct this in next version. Thank for the reviewing this patch. I am going to answer your second question tomorrow. The quick answer is actually yes, but there are caveats, that I will explain tomorrow. Respectfully, Aleksandar ________________________________________ From: Peter Maydell [peter.mayd...@linaro.org] Sent: Tuesday, October 04, 2016 1:42 PM To: Aleksandar Markovic Cc: QEMU Developers; Riku Voipio; Laurent Vivier; Aurelien Jarno; Yongbok Kim; Leon Alrae; Petar Jovanovic; Miodrag Dinic; Aleksandar Rikalo; Aleksandar Markovic Subject: Re: [PATCH 4/4] linux-user: Fix fadvise64() syscall support for Mips32 On 4 October 2016 at 11:05, Aleksandar Markovic <aleksandar.marko...@rt-rk.com> wrote: > From: Aleksandar Markovic <aleksandar.marko...@imgtec.com> > > By looking at the file arch/mips/kernel/sys.S in Linux kernel, There doesn't appear to be a file by that name: http://lxr.free-electrons.com/source/arch/mips/kernel/ > it can be deduced that, for Mips32 platform, syscall > corresponding to number _NR_fadvise64 translates to kernel > function sys_fadvise64_64, and that argument layout is as > follows: > 0 32 0 32 > +----------------+----------------+ > (arg1) | fd | __pad | (arg2) > +----------------+----------------+ > (arg3) | buffer | (arg4) > +----------------+----------------+ > (arg5) | len | (arg6) > +----------------+----------------+ > (arg7) | advise | not used | (arg8) > +----------------+----------------+ > > This can be deduced from glibc code as well, and relevant commits > in linux kernel and glibc. > > Mips32 uniqness is that it does not define _NR_fadvise64_64, > however its fadvise64 implemantation is identical to > fadvise64_64 impleanentation on most other platforms. > > This patch also fixes the failure LTP test posix_fadvise03, if > executed on Qemu-emulated Mips32 platform (user mode). We could alternatively fix this by having #define TARGET_NR_fadvise64_64 (TARGET_NR_Linux + 254) in linux-user/mips/syscall_nr.h rather than #define TARGET_NR_fadvise64 (TARGET_NR_Linux + 254) right? thanks -- PMM
