On Tue, Oct 7, 2014 at 12:21 PM, Rich Felker <dalias@xxxxxxxx> wrote: > On Tue, Oct 07, 2014 at 12:16:59PM -0700, Leonid Yegoshin wrote: >> On 10/07/2014 12:09 PM, Rich Felker wrote: >> >I agree completely here. We should not break things (or, as it >> >seems, leave them broken) for common usage cases that affect >> >everyone just to coddle proprietary vendor-specific instructions. >> >The latter just should not be used in delay slots unless the chip >> >vendor also promises to provide fpu branch in hardware. Rich >> And what do you propose - remove a current in-stack emulation and >> you still think it doesn't break a status-quo? > > The in-stack trampoline support could be left but used only for > emulating instructions the kernel doesn't know. This would make all > normal binaries immediately usable with non-executable stack, and > would avoid the only potential source of regressions. Ultimately I > think the "xol" stuff should be removed, but that could be a long term > goal. Does anything break if the xol stuff is disabled for PT_GNU_STACK tasks? > > Rich -- Andy Lutomirski AMA Capital Management, LLC
