powerpc/kernel: Switch to using MAX_ERRNO

2015-07-29T01:56:11Z

Currently on powerpc we have our own #define for the highest (negative) errno value, called _LAST_ERRNO. This is defined to be 516, for reasons which are not clear. The generic code, and x86, use MAX_ERRNO, which is defined to be 4095. In particular seccomp uses MAX_ERRNO to restrict the value that a seccomp filter can return. Currently with the mismatch between _LAST_ERRNO and MAX_ERRNO, a seccomp tracer wanting to return 600, expecting it to be seen as an error, would instead find on powerpc that userspace sees a successful syscall with a return value of 600. To avoid this inconsistency, switch powerpc to use MAX_ERRNO. We are somewhat confident that generic syscalls that can return a non-error value above negative MAX_ERRNO have already been updated to use force_successful_syscall_return(). I have also checked all the powerpc specific syscalls, and believe that none of them expect to return a non-error value between -MAX_ERRNO and -516. So this change should be safe ... Acked-by: Benjamin Herrenschmidt Signed-off-by: Michael Ellerman Reviewed-by: Kees Cook

UAPI: (Scripted) Disintegrate arch/powerpc/include/asm

2012-10-09T08:47:26Z

Signed-off-by: David Howells Acked-by: Arnd Bergmann Acked-by: Thomas Gleixner Acked-by: Michael Kerrisk Acked-by: Paul E. McKenney Acked-by: Dave Jones

kernel/arch/powerpc/include/uapi/asm/errno.h, branch linux-4.3.y

powerpc/kernel: Switch to using MAX_ERRNO

UAPI: (Scripted) Disintegrate arch/powerpc/include/asm