The file just provides the function get_arch_regstr, however, if in
the only caller get_dwarf_regstr EM_HOST is used for the EM_NONE case
the function can never be called. So remove as dead code. Tidy up the
EM_NONE cases for s390 in dwarf-regs.c.

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/arch/s390/util/Build        |  1 -
 tools/perf/arch/s390/util/dwarf-regs.c | 16 ----------------
 tools/perf/util/dwarf-regs.c           |  4 ++--
 tools/perf/util/include/dwarf-regs.h   |  2 +-
 4 files changed, 3 insertions(+), 20 deletions(-)
 delete mode 100644 tools/perf/arch/s390/util/dwarf-regs.c

diff --git a/tools/perf/arch/s390/util/Build b/tools/perf/arch/s390/util/Build
index 787410f99bb3..736c0ad09194 100644
--- a/tools/perf/arch/s390/util/Build
+++ b/tools/perf/arch/s390/util/Build
@@ -2,7 +2,6 @@ perf-util-y += header.o
 perf-util-$(CONFIG_LIBTRACEEVENT) += kvm-stat.o
 perf-util-y += perf_regs.o
 
-perf-util-$(CONFIG_LIBDW) += dwarf-regs.o
 perf-util-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o
 
 perf-util-y += machine.o
diff --git a/tools/perf/arch/s390/util/dwarf-regs.c b/tools/perf/arch/s390/util/dwarf-regs.c
deleted file mode 100644
index 5bcf3192623a..000000000000
--- a/tools/perf/arch/s390/util/dwarf-regs.c
+++ /dev/null
@@ -1,16 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Mapping of DWARF debug register numbers into register names.
- *
- * Copyright IBM Corp. 2010, 2017
- * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
- *
- */
-
-#include <linux/kernel.h>
-#include "dwarf-regs-table.h"
-
-const char *get_arch_regstr(unsigned int n)
-{
-	return (n >= ARRAY_SIZE(s390_dwarf_regs)) ? NULL : s390_dwarf_regs[n];
-}
diff --git a/tools/perf/util/dwarf-regs.c b/tools/perf/util/dwarf-regs.c
index 2c6b197556dd..1649fc07f4f5 100644
--- a/tools/perf/util/dwarf-regs.c
+++ b/tools/perf/util/dwarf-regs.c
@@ -34,7 +34,7 @@ const char *get_dwarf_regstr(unsigned int n, unsigned int machine, unsigned int
 {
 #if EM_HOST == EM_X86_64 || EM_HOST == EM_386 || EM_HOST == EM_AARCH64 || EM_HOST == EM_ARM \
     || EM_HOST == EM_CSKY || EM_HOST == EM_LOONGARCH || EM_HOST == EM_MIPS || EM_HOST == EM_PPC \
-    || EM_HOST == EM_PPC64 || EM_HOST == EM_RISCV
+    || EM_HOST == EM_PPC64 || EM_HOST == EM_RISCV || EM_HOST == EM_S390
 	if (machine == EM_NONE) {
 		/* Generic arch - use host arch */
 		machine = EM_HOST;
@@ -43,7 +43,7 @@ const char *get_dwarf_regstr(unsigned int n, unsigned int machine, unsigned int
 	switch (machine) {
 #if EM_HOST != EM_X86_64 && EM_HOST != EM_386 && EM_HOST != EM_AARCH64 && EM_HOST != EM_ARM \
     && EM_HOST != EM_CSKY && EM_HOST != EM_LOONGARCH && EM_HOST != EM_MIPS && EM_HOST != EM_PPC \
-    && EM_HOST != EM_PPC64 && EM_HOST != EM_RISCV
+    && EM_HOST != EM_PPC64 && EM_HOST != EM_RISCV && EM_HOST != EM_S390
 	case EM_NONE:	/* Generic arch - use host arch */
 		return get_arch_regstr(n);
 #endif
diff --git a/tools/perf/util/include/dwarf-regs.h b/tools/perf/util/include/dwarf-regs.h
index 28075de8bcf4..086b537690d7 100644
--- a/tools/perf/util/include/dwarf-regs.h
+++ b/tools/perf/util/include/dwarf-regs.h
@@ -91,7 +91,7 @@
 #ifdef HAVE_LIBDW_SUPPORT
 #if !defined(__x86_64__) && !defined(__i386__) && !defined(__aarch64__) && !defined(__arm__) \
     && !defined(__loongarch__) && !defined(__mips__) && !defined(__powerpc__) \
-    && !defined(__powerpc64__) && !defined(__riscv__)
+    && !defined(__powerpc64__) && !defined(__riscv__) && !defined(__s390x__)
 const char *get_arch_regstr(unsigned int n);
 #endif
 
-- 
2.47.0.277.g8800431eea-goog