Messages in this thread | | | Date | Wed, 1 May 2019 21:03:48 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC][PATCH] ftrace/x86: Emulate call function while updating in breakpoint handler |
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On Wed, May 01, 2019 at 02:58:24PM -0400, Steven Rostedt wrote: > > + if (ftrace_location(ip)) { > > + int3_emulate_call(regs, ftrace_update_func_call); > > Should be: > > int3_emulate_call(regs, (unsigned long)ftrace_regs_caller);
Ah, I lost the plot a little there.
> > + return 1; > > + } else if (is_ftrace_caller(ip)) { > > + if (!ftrace_update_func_call) { > > + int3_emulate_jmp(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE); > > I see what you did here, but I think: > > int3_emulate_jmp(regs, ip + CALL_INSN_SIZE); > > looks better. But that said, we could in the beginning do: > > ip = regs->ip - INT3_INSN_SIZE; > > instead of > > ip = regs->ip - 1; > > I made these updates and posted them to Linus.
I was actually considering:
static inline void int3_emulate_nop(struct pt_regs *regs, unsigned long size) { int3_emulate_jmp(regs, regs->ip - INT3_INSN_SIZE + size); }
And then the above becomes:
int3_emulate_nop(regs, CALL_INSN_SIZE);
Hmm?
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