Re: [PATCH v2 17/31] perf dwarf-regs: Pass ELF flags to get_dwarf_regstr

[Masami Hiramatsu (Google) <mhiramat@kernel.org>]

On Sat,  5 Oct 2024 12:55:27 -0700
Ian Rogers <irogers@google.com> wrote:

> Pass a flags value as architectures like csky need the flags to
> determine the ABI variant.
> 

Same here. I need some examples of this chaneg.

Thank you,

> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>  tools/perf/util/dwarf-regs.c         |  3 ++-
>  tools/perf/util/include/dwarf-regs.h | 11 ++++++-----
>  tools/perf/util/probe-finder.c       | 13 +++++++------
>  tools/perf/util/probe-finder.h       |  3 ++-
>  4 files changed, 17 insertions(+), 13 deletions(-)
> 
> diff --git a/tools/perf/util/dwarf-regs.c b/tools/perf/util/dwarf-regs.c
> index 1321387f6948..86b3ef638fbb 100644
> --- a/tools/perf/util/dwarf-regs.c
> +++ b/tools/perf/util/dwarf-regs.c
> @@ -29,7 +29,8 @@
>  #define __get_dwarf_regstr(tbl, n) (((n) < ARRAY_SIZE(tbl)) ? (tbl)[(n)] : NULL)
>  
>  /* Return architecture dependent register string (for kprobe-tracer) */
> -const char *get_dwarf_regstr(unsigned int n, unsigned int machine)
> +const char *get_dwarf_regstr(unsigned int n, unsigned int machine,
> +			     unsigned int flags __maybe_unused)
>  {
>  	switch (machine) {
>  	case EM_NONE:	/* Generic arch - use host arch */
> diff --git a/tools/perf/util/include/dwarf-regs.h b/tools/perf/util/include/dwarf-regs.h
> index ee0a734564c7..925525405e2d 100644
> --- a/tools/perf/util/include/dwarf-regs.h
> +++ b/tools/perf/util/include/dwarf-regs.h
> @@ -80,12 +80,13 @@
>  
>  #ifdef HAVE_LIBDW_SUPPORT
>  const char *get_arch_regstr(unsigned int n);
> -/*
> - * get_dwarf_regstr - Returns ftrace register string from DWARF regnum
> - * n: DWARF register number
> - * machine: ELF machine signature (EM_*)
> +/**
> + * get_dwarf_regstr() - Returns ftrace register string from DWARF regnum.
> + * @n: DWARF register number.
> + * @machine: ELF machine signature (EM_*).
> + * @flags: ELF flags for things like ABI differences.
>   */
> -const char *get_dwarf_regstr(unsigned int n, unsigned int machine);
> +const char *get_dwarf_regstr(unsigned int n, unsigned int machine, unsigned int flags);
>  
>  int get_arch_regnum(const char *name);
>  /*
> diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
> index 8019d232f515..29eaa9beca86 100644
> --- a/tools/perf/util/probe-finder.c
> +++ b/tools/perf/util/probe-finder.c
> @@ -56,7 +56,7 @@ static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
>   */
>  static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
>  				     Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
> -				     unsigned int machine,
> +				     const struct probe_finder *pf,
>  				     struct probe_trace_arg *tvar)
>  {
>  	Dwarf_Attribute attr;
> @@ -166,7 +166,7 @@ static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
>  	if (!tvar)
>  		return ret2;
>  
> -	regs = get_dwarf_regstr(regn, machine);
> +	regs = get_dwarf_regstr(regn, pf->e_machine, pf->e_flags);
>  	if (!regs) {
>  		/* This should be a bug in DWARF or this tool */
>  		pr_warning("Mapping for the register number %u "
> @@ -451,7 +451,7 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
>  		 dwarf_diename(vr_die));
>  
>  	ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
> -					&pf->sp_die, pf->machine, pf->tvar);
> +					&pf->sp_die, pf, pf->tvar);
>  	if (ret == -ENOENT && pf->skip_empty_arg)
>  		/* This can be found in other place. skip it */
>  		return 0;
> @@ -1134,7 +1134,8 @@ static int debuginfo__find_probes(struct debuginfo *dbg,
>  	if (gelf_getehdr(elf, &ehdr) == NULL)
>  		return -EINVAL;
>  
> -	pf->machine = ehdr.e_machine;
> +	pf->e_machine = ehdr.e_machine;
> +	pf->e_flags = ehdr.e_flags;
>  
>  	do {
>  		GElf_Shdr shdr;
> @@ -1171,7 +1172,7 @@ static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
>  	    (tag == DW_TAG_variable && vf->vars)) {
>  		if (convert_variable_location(die_mem, vf->pf->addr,
>  					      vf->pf->fb_ops, &pf->sp_die,
> -					      pf->machine, NULL) == 0) {
> +					      pf, /*tvar=*/NULL) == 0) {
>  			vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
>  			if (vf->args[vf->nargs].var == NULL) {
>  				vf->ret = -ENOMEM;
> @@ -1403,7 +1404,7 @@ static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
>  	    tag == DW_TAG_variable) {
>  		ret = convert_variable_location(die_mem, af->pf.addr,
>  						af->pf.fb_ops, &af->pf.sp_die,
> -						af->pf.machine, NULL);
> +						&af->pf, /*tvar=*/NULL);
>  		if (ret == 0 || ret == -ERANGE) {
>  			int ret2;
>  			bool externs = !af->child;
> diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
> index b9a5afca4cc1..71e21cb4492a 100644
> --- a/tools/perf/util/probe-finder.h
> +++ b/tools/perf/util/probe-finder.h
> @@ -68,7 +68,8 @@ struct probe_finder {
>  	/* Call Frame Information from .debug_frame */
>  	Dwarf_CFI		*cfi_dbg;
>  	Dwarf_Op		*fb_ops;	/* Frame base attribute */
> -	unsigned int		machine;	/* Target machine arch */
> +	unsigned int		e_machine;	/* ELF target machine arch */
> +	unsigned int		e_flags;	/* ELF target machine flags */
>  	struct perf_probe_arg	*pvar;		/* Current target variable */
>  	struct probe_trace_arg	*tvar;		/* Current result variable */
>  	bool			skip_empty_arg;	/* Skip non-exist args */
> -- 
> 2.47.0.rc0.187.ge670bccf7e-goog
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>