Re: [PATCHv2 RFC bpf-next 0/7] bpf: Add support for ftrace probe

On Thu, Apr 15, 2021 at 02:21:20PM -0400, Steven Rostedt wrote:

On Thu, 15 Apr 2021 14:18:31 -0400
Steven Rostedt [off-list ref] wrote:

quoted

My last release of that code is here:

  https://lore.kernel.org/lkml/20190525031633.811342628@goodmis.org/ (local)

It allows you to "reserve data" to pass from the caller to the return, and
that could hold the arguments. See patch 15 of that series.

Note that implementation only lets you save up to 4 words on the stack, but
that can be changed. Or you could have a separate shadow stack for saving
arguments, and only pass the pointer to the location on the other stack
where those arguments are.

right, I quickly checked on that and it looks exactly like
the thing we need

I'll try to rebase that on the current code and try to use
it with the bpf ftrace probe to see how it fits

any chance you could plan on reposting it? ;-)

thanks,
jirka