perf dwarf-regs: Pass ELF flags to get_dwarf_regstr

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

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Anup Patel <anup@brainfault.org>
Cc: Yang Jihong <yangjihong@bytedance.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Shenlin Liang <liangshenlin@eswincomputing.com>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Guilherme Amadio <amadio@gentoo.org>
Cc: Steinar H. Gunderson <sesse@google.com>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: Alexander Lobakin <aleksander.lobakin@intel.com>
Cc: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: James Clark <james.clark@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Chen Pei <cp0613@linux.alibaba.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Aditya Gupta <adityag@linux.ibm.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-riscv@lists.infradead.org
Cc: Bibo Mao <maobibo@loongson.cn>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Atish Patra <atishp@rivosinc.com>
Cc: Dima Kogan <dima@secretsauce.net>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Dr. David Alan Gilbert <linux@treblig.org>
Cc: linux-csky@vger.kernel.org
Link: https://lore.kernel.org/r/20241108234606.429459-7-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Author: captain5050

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 */

tools/perf/util/include/dwarf-regs.h

@@ -90,12 +90,13 @@
 
 #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);
 /*

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;
@@ -1402,7 +1403,7 @@ 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;

tools/perf/util/probe-finder.h

@@ -68,7 +68,8 @@ struct probe_finder {
 	/* Call Frame Information from .debug_frame. Not owned. */
 	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 */