Re: [tip: x86/asm] x86/asm: Make ASM_CALL_CONSTRAINT conditional on frame pointers

[David Laight <david.laight.linux@xxxxxxxxx>]

On Fri, 7 Mar 2025 17:38:14 -0800
Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:

...
> We hopefully won't need those hacks much longer anyway, as I'll have
> another series to propose removing frame pointers for x86-64.
> 
> x86-32 can keep frame pointers, but doesn't need the constraints.  It's
> not supported for livepatch so it doesn't need to be 100% reliable.
> Worst case, an unwind skips a frame, but the call address still shows up
> on stack trace dumps prepended with '?'.

Doesn't 'user copy hardening' also do stack following?
That needs to find all the stack frames (that have locals) and I think
is is more reliable with frame pointers.

	David