Re: [DTrace-devel] [PATCH 29/38] Allow relocation of the ERROR PRID

From: Kris Van Hees <kris.van.hees@oracle.com>
To: eugene.loh@oracle.com
Cc: dtrace@lists.linux.dev, dtrace-devel@oss.oracle.com
Subject: Re: [DTrace-devel] [PATCH 29/38] Allow relocation of the ERROR PRID
Date: Fri, 19 Jul 2024 17:41:09 -0400	[thread overview]
Message-ID: <ZprddULVHQOJhnpT@oracle.com> (raw)
In-Reply-To: <20240627053904.21996-10-eugene.loh@oracle.com>

Why is this patch needed?  As far as I can see, BEGIN, END, and ERROR are
always created as the first 3 probes (in that order), so they will have probe
IDs 1, 2, and 3.

On Thu, Jun 27, 2024 at 01:38:55AM -0400, eugene.loh--- via DTrace-devel wrote:
> From: Eugene Loh <eugene.loh@oracle.com>
> 
> Signed-off-by: Eugene Loh <eugene.loh@oracle.com>
> ---
>  libdtrace/dt_bpf.h   | 1 +
>  libdtrace/dt_cc.c    | 3 +++
>  libdtrace/dt_dlibs.c | 1 +
>  3 files changed, 5 insertions(+)
> 
> diff --git a/libdtrace/dt_bpf.h b/libdtrace/dt_bpf.h
> index 5b2df264..58cf29cc 100644
> --- a/libdtrace/dt_bpf.h
> +++ b/libdtrace/dt_bpf.h
> @@ -56,6 +56,7 @@ extern "C" {
>  #define DT_CONST_ZERO_OFF		22
>  #define DT_CONST_STACK_OFF		23
>  #define DT_CONST_STACK_SKIP		24
> +#define DT_CONST_ERROR_PRID		25
>  
>  #define DT_BPF_LOG_SIZE_DEFAULT	(UINT32_MAX >> 8)
>  #define DT_BPF_LOG_SIZE_SMALL	4096
> diff --git a/libdtrace/dt_cc.c b/libdtrace/dt_cc.c
> index d1ee3843..3d9a9c79 100644
> --- a/libdtrace/dt_cc.c
> +++ b/libdtrace/dt_cc.c
> @@ -1076,6 +1076,9 @@ dt_link_construct(dtrace_hdl_t *dtp, const dt_probe_t *prp, dtrace_difo_t *dp,
>  				nrp->dofr_data = sizeof(uint64_t)
>  				    * dtp->dt_options[DTRACEOPT_MAXFRAMES];
>  				continue;
> +			case DT_CONST_ERROR_PRID:
> +				nrp->dofr_data = dtp->dt_error->desc->id;
> +				continue;
>  			case DT_CONST_BOOTTM:
>  				if (boottime == 0 && get_boottime())
>  					return -1;
> diff --git a/libdtrace/dt_dlibs.c b/libdtrace/dt_dlibs.c
> index bc883e11..1fb561ad 100644
> --- a/libdtrace/dt_dlibs.c
> +++ b/libdtrace/dt_dlibs.c
> @@ -80,6 +80,7 @@ static const dt_ident_t		dt_bpf_symbols[] = {
>  	DT_BPF_SYMBOL_ID(STBSZ, DT_IDENT_SCALAR, DT_CONST_STBSZ),
>  	DT_BPF_SYMBOL_ID(STRSZ, DT_IDENT_SCALAR, DT_CONST_STRSZ),
>  	DT_BPF_SYMBOL_ID(STKSIZ, DT_IDENT_SCALAR, DT_CONST_STKSIZ),
> +	DT_BPF_SYMBOL_ID(ERROR_PRID, DT_IDENT_SCALAR, DT_CONST_ERROR_PRID),
>  	DT_BPF_SYMBOL_ID(BOOTTM, DT_IDENT_SCALAR, DT_CONST_BOOTTM),
>  	DT_BPF_SYMBOL_ID(NSPEC, DT_IDENT_SCALAR, DT_CONST_NSPEC),
>  	DT_BPF_SYMBOL_ID(NCPUS, DT_IDENT_SCALAR, DT_CONST_NCPUS),
> -- 
> 2.18.4
> 
> 
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