perf build: Remove PERF_HAVE_DWARF_REGS

PERF_HAVE_DWARF_REGS was true when an architecture had a dwarf-regs.c
file. There are no more architecture dwarf-regs.c files, selection is
done using constants from the ELF file rather than conditional
compilation. When removing PERF_HAVE_DWARF_REGS was the only variable
in the Makefile, remove the Makefile.

Add missing SPDX for RISC-V Makefile.

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/20241108234606.429459-21-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Author: captain5050

tools/perf/Makefile.config

@@ -559,15 +559,10 @@ ifndef NO_LIBELF
   endif
 
   ifndef NO_LIBDW
-    ifeq ($(origin PERF_HAVE_DWARF_REGS), undefined)
-      $(warning DWARF register mappings have not been defined for architecture $(SRCARCH), DWARF support disabled)
-      NO_LIBDW := 1
-    else
-      CFLAGS += -DHAVE_LIBDW_SUPPORT $(LIBDW_CFLAGS)
-      LDFLAGS += $(LIBDW_LDFLAGS)
-      EXTLIBS += ${DWARFLIBS}
-      $(call detected,CONFIG_LIBDW)
-    endif # PERF_HAVE_DWARF_REGS
+    CFLAGS += -DHAVE_LIBDW_SUPPORT $(LIBDW_CFLAGS)
+    LDFLAGS += $(LIBDW_LDFLAGS)
+    EXTLIBS += ${DWARFLIBS}
+    $(call detected,CONFIG_LIBDW)
   endif # NO_LIBDW
 
   ifndef NO_LIBBPF

tools/perf/arch/arm/Makefile

@@ -1,5 +1,2 @@
 # SPDX-License-Identifier: GPL-2.0-only
-ifndef NO_LIBDW
-PERF_HAVE_DWARF_REGS := 1
-endif
 PERF_HAVE_JITDUMP := 1

tools/perf/arch/arm64/Makefile

@@ -1,7 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
-ifndef NO_LIBDW
-PERF_HAVE_DWARF_REGS := 1
-endif
 PERF_HAVE_JITDUMP := 1
 HAVE_KVM_STAT_SUPPORT := 1
 

tools/perf/arch/csky/Makefile

@@ -1,7 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
-ifndef NO_LIBDW
-PERF_HAVE_DWARF_REGS := 1
-endif
 PERF_HAVE_JITDUMP := 1
 HAVE_KVM_STAT_SUPPORT := 1
 

tools/perf/arch/loongarch/Makefile

@@ -1,8 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
-ifndef NO_LIBDW
-PERF_HAVE_DWARF_REGS := 1
-endif
-
 # Syscall table generation for perf
 out    := $(OUTPUT)arch/mips/include/generated/asm
 header := $(out)/syscalls_n64.c

tools/perf/arch/mips/Makefile

@@ -1,8 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
-ifndef NO_LIBDW
-PERF_HAVE_DWARF_REGS := 1
-endif
-
 HAVE_KVM_STAT_SUPPORT := 1
 PERF_HAVE_JITDUMP := 1
 

tools/perf/arch/powerpc/Makefile

@@ -1,6 +1,4 @@
-ifndef NO_LIBDW
-PERF_HAVE_DWARF_REGS := 1
-endif
+# SPDX-License-Identifier: GPL-2.0
 PERF_HAVE_JITDUMP := 1
 HAVE_KVM_STAT_SUPPORT := 1
 

tools/perf/arch/riscv/Makefile

@@ -1,7 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-ifndef NO_LIBDW
-PERF_HAVE_DWARF_REGS := 1
-endif
 HAVE_KVM_STAT_SUPPORT := 1
 PERF_HAVE_JITDUMP := 1