Re: [PATCH] consistently use MAX_ERRNO in __syscall_return

[Randy.Dunlap]

On Mon, 03 Jul 2006 08:03:29 -0700 H. Peter Anvin wrote:

> Andrew Morton wrote:
> > On Sun, 2 Jul 2006 11:27:22 -0700
> > "Randy.Dunlap" <rdunlap@xxxxxxxxxxxx> wrote:
> > 
> >> --- linux-2617-g20.orig/include/asm-i386/unistd.h
> >> +++ linux-2617-g20/include/asm-i386/unistd.h
> >> @@ -327,14 +327,15 @@
> >>  #ifdef __KERNEL__
> >>  
> >>  #define NR_syscalls 318
> >> +#include <linux/err.h>
> > 
> > include/linux/err.h: Assembler messages:
> > include/linux/err.h:20: Error: no such instruction: `static inline void *ERR_PTR(long error)'
> > include/linux/err.h:21: Error: junk at end of line, first unrecognized character is `{'
> > include/linux/err.h:22: Error: no such instruction: `return (void *)error'
> > include/linux/err.h:23: Error: junk at end of line, first unrecognized character is `}'
> > include/linux/err.h:25: Error: no such instruction: `static inline long PTR_ERR(const void *ptr)'
> > include/linux/err.h:26: Error: junk at end of line, first unrecognized character is `{'
> > include/linux/err.h:27: Error: no such instruction: `return (long)ptr'
> > include/linux/err.h:28: Error: junk at end of line, first unrecognized character is `}'
> > include/linux/err.h:30: Error: no such instruction: `static inline long IS_ERR(const void *ptr)'
> > include/linux/err.h:31: Error: junk at end of line, first unrecognized character is `{'
> > include/linux/err.h:32: Error: no such instruction: `return unlikely(((unsigned long)ptr)>=(unsigned long)-4095)'
> > include/linux/err.h:33: Error: junk at end of line, first unrecognized character is `}'
> > distcc[7619] ERROR: compile (null) on localhost failed
> > make[1]: *** [arch/i386/kernel/vsyscall-sysenter.o] Error 1
> > make: *** [arch/i386/kernel/vsyscall-sysenter.o] Error 2

Built for me on i386 and x86_64.

> unlikely() shouldn't be used in code exported to user space.  At least 
> one architecture simply open-codes the __builtin_expect(); or we could
> introduce __likely() and __unlikely() for the benefit of userspace.

How did you determine that this had something to do with
userspace?

---
~Randy
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