On Jun 10, 2015 5:07 AM, "Josh Poimboeuf" <jpoimboe@xxxxxxxxxx> wrote: > > Add a new CONFIG_ASM_VALIDATION option which adds an asmvalidate host > tool which runs on every compiled .S file. Its goal is to enforce sane > rules on all asm code, so that stack debug metadata (frame/back chain > pointers and/or DWARF CFI metadata) can be made reliable. > > It enforces the following rules: > > 1. Each callable function must be annotated with the ELF STT_FUNC type. > This is typically done using the ENTRY/ENDPROC macros. If > asmvalidate finds a return instruction outside of a function, it > flags an error, since that usually indicates callable code which > should be annotated accordingly. > > 2. Each callable function must never leave its own bounds (i.e. with a > jump to outside the function) except when returning. Won't that break with sibling/tail calls? GCC can generate those, and the ia32_ptregs_common label is an example of such a thing. I'd rather have the script understand tail calls and possibly require that ia32_ptregs_common have a dummy frame pointer save in front before the label if needed. --Andy -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
