Messages in this thread | | | Date | Mon, 21 Apr 2014 19:52:38 +0200 | Subject | Re: [PATCH 16/28] nios2: System calls handling | From | Richard Weinberger <> |
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On Mon, Apr 21, 2014 at 7:32 PM, Ley Foon Tan <lftan@altera.com> wrote: > On Sun, Apr 20, 2014 at 12:09 AM, Pavel Machek <pavel@denx.de> wrote: >>> +/* Additional Nios II specific syscalls. */ >>> +#define __NR_cacheflush (__NR_arch_specific_syscall) >>> +__SYSCALL(__NR_cacheflush, sys_cacheflush) >> >> I guess you should Cc: Michael Kerrisk on this one. > CC him this email. > >> >> Also... explanation why you need this syscall while other >> architectures live happily without it would be nice. > This syscall exist in nios2 port since old days and some users already > used it for sometimes. > Like mentioned by Greet, 12 our of 28 architectures provide such a syscall. > >>> +/* sys_cacheflush -- flush the processor cache. */ >>> +asmlinkage int sys_cacheflush(unsigned long addr, unsigned long len, >>> + unsigned int op) >>> +{ >>> + struct vm_area_struct *vma; >>> + >>> + if (len == 0) >>> + return 0; >> >> op is being ignored? You should remove it... or if (op) return -EINVAL >> if you want future extensions. > Yes, op argument is being ignored. Okay, will add the return -EINVAL > if op is non-zero.
Be careful. If existing applications already use this and maybe pass a dummy value to it you break them.
-- Thanks, //richard
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