Re: [RFC][PATCH 3/3] x86/entry, ORC: Teach objtool/unwind_orc about stack irq swizzles

On Fri, May 08, 2020 at 02:26:32PM +0200, Thomas Gleixner wrote: > Peter Zijlstra writes: > > > On Thu, May 07, 2020 at 11:24:49PM +0200, Thomas Gleixner wrote: > >> But over our IRC conversation I came up with a 3rd variant: > >> > >> For most of the vectors the indirect call overhead is

Re: [RFC][PATCH 3/3] x86/entry, ORC: Teach objtool/unwind_orc about stack irq swizzles

Thomas Gleixner writes: > Peter Zijlstra writes: >> Are we sure the rat-poison crap is noise for all the other system >> vectors? I suppose it is for most since they'll do indirect calls >> themselves anyway, right? > > 3) Quick > > RESCHEDULE_VECTOR > > POSTED_INTR_VECTOR >

Re: [RFC][PATCH 3/3] x86/entry, ORC: Teach objtool/unwind_orc about stack irq swizzles

Peter Zijlstra writes: > On Thu, May 07, 2020 at 11:24:49PM +0200, Thomas Gleixner wrote: >> But over our IRC conversation I came up with a 3rd variant: >> >> For most of the vectors the indirect call overhead is just noise, so >> we can run them through the ASM switcher, but for the

Re: [RFC][PATCH 3/3] x86/entry, ORC: Teach objtool/unwind_orc about stack irq swizzles

On Thu, May 07, 2020 at 11:24:49PM +0200, Thomas Gleixner wrote: > But over our IRC conversation I came up with a 3rd variant: > > For most of the vectors the indirect call overhead is just noise, so > we can run them through the ASM switcher, but for the resched IPI > we can just use a

Re: [RFC][PATCH 3/3] x86/entry, ORC: Teach objtool/unwind_orc about stack irq swizzles

Josh Poimboeuf writes: > On Thu, May 07, 2020 at 07:38:09PM +0200, Peter Zijlstra wrote: >> On Thu, May 07, 2020 at 06:10:23PM +0200, Peter Zijlstra wrote: >> Much simpler, also works. > > Doing the stack switch in inline asm is just nasty. Matter of personal preference :) > Also, a frame

Re: [RFC][PATCH 3/3] x86/entry, ORC: Teach objtool/unwind_orc about stack irq swizzles

On Thu, May 07, 2020 at 07:38:09PM +0200, Peter Zijlstra wrote: > On Thu, May 07, 2020 at 06:10:23PM +0200, Peter Zijlstra wrote: > > Thomas would very much like objtool to understand and generate correct > > ORC unwind information for the minimal stack swizzle sequence: > > > > mov %rsp,

Re: [RFC][PATCH 3/3] x86/entry, ORC: Teach objtool/unwind_orc about stack irq swizzles

On Thu, May 07, 2020 at 06:10:23PM +0200, Peter Zijlstra wrote: > Thomas would very much like objtool to understand and generate correct > ORC unwind information for the minimal stack swizzle sequence: > > mov %rsp, (%[ts]) > mov %[ts], %rsp > ... > pop %rsp > > This

[RFC][PATCH 3/3] x86/entry, ORC: Teach objtool/unwind_orc about stack irq swizzles

Thomas would very much like objtool to understand and generate correct ORC unwind information for the minimal stack swizzle sequence: mov %rsp, (%[ts]) mov %[ts], %rsp ... pop %rsp This sequence works for the fp and guess unwinders -- all they need is that