[DTrace-devel] [PATCH 1/2] bpf: add PC to fault reporting using dt_probe_error()

[Eugene Loh]

Reviewed-by: Eugene Loh <eugene.loh at oracle.com>
but surely it's possible to have at least rudimentary tests for this.

On 5/11/23 01:23, Kris Van Hees via DTrace-devel wrote:
> Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
> ---
>   bpf/get_bvar.c    | 3 ++-
>   bpf/speculation.c | 3 ++-
>   2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/bpf/get_bvar.c b/bpf/get_bvar.c
> index ef2e2ca6..4fc6b880 100644
> --- a/bpf/get_bvar.c
> +++ b/bpf/get_bvar.c
> @@ -23,13 +23,14 @@ extern struct bpf_map_def cpuinfo;
>   extern struct bpf_map_def probes;
>   extern struct bpf_map_def state;
>   
> +extern uint64_t PC;
>   extern uint64_t STBSZ;
>   extern uint64_t STKSIZ;
>   extern uint64_t BOOTTM;
>   
>   #define error(dctx, fault, illval) \
>   	({ \
> -		dt_probe_error((dctx), -1, (fault), (illval)); \
> +		dt_probe_error((dctx), (uint64_t)&PC, (fault), (illval)); \
>   		-1; \
>   	})
>   
> diff --git a/bpf/speculation.c b/bpf/speculation.c
> index 6e032a44..c565c8da 100644
> --- a/bpf/speculation.c
> +++ b/bpf/speculation.c
> @@ -20,6 +20,7 @@
>   
>   extern struct bpf_map_def specs;
>   extern struct bpf_map_def state;
> +extern uint64_t PC;
>   extern uint64_t NSPEC;
>   
>   /*
> @@ -151,7 +152,7 @@ dt_speculation_set_drainable(const dt_dctx_t *dctx, uint32_t id)
>   	if ((spec = bpf_map_lookup_elem(&specs, &id)) == NULL) {
>   		if (id <= (uint64_t) &NSPEC)
>   			return 0;
> -		dt_probe_error(dctx, -1, DTRACEFLT_ILLOP, 0);
> +		dt_probe_error(dctx, (uint64_t)&PC, DTRACEFLT_ILLOP, 0);
>   		return -1;
>   	}
>   	spec->draining = 1;