On 12/14/2015 03:47 PM, Andy Lutomirski wrote: > On Mon, Dec 14, 2015 at 3:44 PM, Dave Hansen <dave@xxxxxxxx> wrote: >> On 12/14/2015 03:39 PM, Andy Lutomirski wrote: >>>>> Nope. My linker-fu is weak. >>>>> >>>>> Can we even depend on the linker by itself? Even if the sections were >>>>> marked --x, we can't actually use them with those permissions unless we >>>>> have protection keys. >>>>> >>>>> Do we need some special tag on the section to tell the linker to map it >>>>> as --x under some conditions and r-x for others? >>>>> >>> Why? Wouldn't --x just end up acting like r-x if PKRU is absent? >> >> An app doing --x would expect it to be unreadable. I don't think we can >> just silently turn it in to r-x. > > I don't see why. After all, an app doing --x right now gets rx. An > app doing r-- still gets r-x on some systems. ... and you're right. I'd managed to convince myself otherwise, somehow. Let me go see if I can get the execve() code to make one of these mappings if I hand it properly-aligned sections. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>