On Tue, May 07, 2019 at 03:20:16PM -0400, Steven Rostedt wrote: > On Tue, 7 May 2019 14:14:12 -0500 > Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote: > > > On Tue, May 07, 2019 at 03:01:53PM -0400, Steven Rostedt wrote: > > > How's this? > > > > > > -- Steve > > > > > > From d29dc2e9e0275c9857932b80cebc01551b669efb Mon Sep 17 00:00:00 2001 > > > From: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > > > Date: Wed, 1 May 2019 15:11:17 +0200 > > > Subject: [PATCH] x86_64: Allow breakpoints to emulate call functions > > > > > > In order to allow breakpoints to emulate call functions, they need to push > > > the return address onto the stack. But because the breakpoint exception > > > frame is added to the stack when the breakpoint is hit, there's no room to > > > add the address onto the stack and return to the address of the emulated > > > called funtion. > > > > The 2nd sentence can probably be removed since it's technically no > > longer true, thanks to the previous patch. > > > > > This helper functions are added: > > > > "These" > > New version: > > x86_64: Allow breakpoints to emulate call functions > > In order to allow breakpoints to emulate call functions, they need to push Sorry to keep nitpicking, but "call functions" -> "function calls" would sound more accurate to me (in both subject and description). Otherwise it looks good. > the return address onto the stack. The x86_64 int3 handler adds a small gap > to allow the stack to grow some. Use this gap to add the return address to > be able to emulate a call instruction at the breakpoint location. > > These helper functions are added: > > int3_emulate_jmp(): changes the location of the regs->ip to return there. > > (The next two are only for x86_64) > int3_emulate_push(): to push the address onto the gap in the stack > int3_emulate_call(): push the return address and change regs->ip -- Josh
