On Wed, Jan 21, 2015, at 19:04, Borislav Petkov wrote: > On Wed, Jan 21, 2015 at 05:20:09PM +0100, Alexander van Heukelum wrote: > > On Wed, Jan 21, 2015, at 14:40, Denys Vlasenko wrote: > > > On Sun, Jan 18, 2015 at 12:45 PM, Alexander van Heukelum > > > <[email protected]> wrote: > > > > The macro THREAD_INFO(reg,offset) is used in assembly to compute the > > > > offset between the user ptregs and the thread_info struct. Change > > > > the macro and all its uses so that offset is given as the current > > > > top of stack in the pt_regs frame. The generated code is identical. > > > > > > What is the purpose of doing this? > > > > > > I don't mean to say that it's pointless, but it is also not obvious > > > why it's better than the code before patch. > > > > Just because I had a hard time understanding what the offset > > parameter means. Turns out Borislav did another variant in his > > patchset. Quoting him from the commit message which made > > that the change: > > > Semi-mysterious expressions THREAD_INFO(%rsp,RIP) - "why RIP??" > > > are now replaced by more logical THREAD_INFO(%rsp,SIZEOF_PTREGS) - > > > "rsp is SIZEOF_PTREGS bytes below the top, calculate > > > thread_info's address using that information" > > > > Borislav expresses "offset" as an offset from the stack's page > > boundary,while I chose the offset from the start of struct > > pt_regs on the stack. > > I've never done any such thing :-) > > s/Borislav/Denys/g.
twice ... and stop using third person too... Oops. Err. sorry :-/. > -- > Regards/Gruss, > Boris. > > ECO tip #101: Trim your mails when you reply. > -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
