Re: [PATCHv6 perf/core 09/22] uprobes/x86: Add uprobe syscall to speed up uprobe

[Oleg Nesterov <oleg@redhat.com>]

On 07/20, Jiri Olsa wrote:
>
> Adding new uprobe syscall that calls uprobe handlers for given
> 'breakpoint' address.
>
> The idea is that the 'breakpoint' address calls the user space
> trampoline which executes the uprobe syscall.
>
> The syscall handler reads the return address of the initial call
> to retrieve the original 'breakpoint' address. With this address
> we find the related uprobe object and call its consumers.
>
> Adding the arch_uprobe_trampoline_mapping function that provides
> uprobe trampoline mapping. This mapping is backed with one global
> page initialized at __init time and shared by the all the mapping
> instances.
>
> We do not allow to execute uprobe syscall if the caller is not
> from uprobe trampoline mapping.
>
> The uprobe syscall ensures the consumer (bpf program) sees registers
> values in the state before the trampoline was called.
>
> Acked-by: Andrii Nakryiko <andrii@kernel.org>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>

My ack still stands,

Acked-by: Oleg Nesterov <oleg@redhat.com>