perf build: Remove NO_LIBDW_DWARF_UNWIND option

Libdw unwinding support is present for every architecture that has a
perf_regs.h - perf registers are needed for the initial frame to
unwind.

Elfutils also supports SPARC, ARC and m68k but there is no support in
the Linux kernel for perf registers on these architectures.

As the perf supported DWARF unwinding architectures are a subset of the
elfutils ones, remove NO_LIBDW_DWARF_UNWIND as there isn't a case of
elfutils lacking the support need for perf.

Signed-off-by: Ian Rogers <[email protected]>
Cc: Aditya Bodkhe <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Athira Rajeev <[email protected]>
Cc: Chun-Tse Shao <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Dr. David Alan Gilbert <[email protected]>
Cc: Guo Ren <[email protected]>
Cc: Haibo Xu <[email protected]>
Cc: Howard Chu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Garry <[email protected]>
Cc: Krzysztof Łopatowski <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Mark Wielaard <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Sergei Trofimovich <[email protected]>
Cc: Shimin Guo <[email protected]>
Cc: Stephen Brennan <[email protected]>
Cc: Thomas Falcon <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: captain5050

tools/perf/Makefile.config

@@ -118,14 +118,6 @@ ifeq ($(ARCH),mips)
   endif
 endif
 
-# So far there's only x86 and arm libdw unwind support merged in perf.
-# Disable it on all other architectures in case libdw unwind
-# support is detected in system. Add supported architectures
-# to the check.
-ifneq ($(SRCARCH),$(filter $(SRCARCH),x86 arm arm64 powerpc s390 csky riscv loongarch))
-  NO_LIBDW_DWARF_UNWIND := 1
-endif
-
 ifneq ($(LIBUNWIND),1)
   NO_LIBUNWIND := 1
 endif
@@ -456,7 +448,6 @@ endif
 ifdef NO_LIBELF
   NO_LIBDW := 1
   NO_LIBUNWIND := 1
-  NO_LIBDW_DWARF_UNWIND := 1
   NO_LIBBPF := 1
   NO_JVMTI := 1
 else
@@ -504,10 +495,6 @@ ifeq ($(feature-libaio), 1)
   endif
 endif
 
-ifdef NO_LIBDW
-  NO_LIBDW_DWARF_UNWIND := 1
-endif
-
 ifeq ($(feature-scandirat), 1)
   # Ignore having scandirat with memory sanitizer that lacks an interceptor.
   ifeq ($(filter s% -fsanitize=memory%,$(EXTRA_CFLAGS),),)
@@ -757,7 +744,7 @@ dwarf-post-unwind-text := BUG
 
 # setup DWARF post unwinder
 ifdef NO_LIBUNWIND
-  ifdef NO_LIBDW_DWARF_UNWIND
+  ifdef NO_LIBDW
     $(warning Disabling post unwind, no support found.)
     dwarf-post-unwind := 0
   else
@@ -767,10 +754,6 @@ ifdef NO_LIBUNWIND
 else
   dwarf-post-unwind-text := libunwind
   $(call detected,CONFIG_LIBUNWIND)
-  # Enable libunwind support by default.
-  ifndef NO_LIBDW_DWARF_UNWIND
-    NO_LIBDW_DWARF_UNWIND := 1
-  endif
 endif
 
 ifeq ($(dwarf-post-unwind),1)

tools/perf/tests/make

@@ -83,7 +83,6 @@ make_no_demangle    := NO_DEMANGLE=1
 make_no_libelf      := NO_LIBELF=1
 make_no_libdw       := NO_LIBDW=1
 make_libunwind      := LIBUNWIND=1
-make_no_libdw_dwarf_unwind := NO_LIBDW_DWARF_UNWIND=1
 make_no_backtrace   := NO_BACKTRACE=1
 make_no_libcapstone := NO_CAPSTONE=1
 make_no_libnuma     := NO_LIBNUMA=1
@@ -120,7 +119,7 @@ make_static         := LDFLAGS=-static NO_PERF_READ_VDSO32=1 NO_PERF_READ_VDSOX3
 make_minimal        := NO_LIBPYTHON=1 NO_GTK2=1
 make_minimal        += NO_DEMANGLE=1 NO_LIBELF=1 NO_BACKTRACE=1
 make_minimal        += NO_LIBNUMA=1 NO_LIBBIONIC=1 NO_LIBDW=1
-make_minimal        += NO_LIBDW_DWARF_UNWIND=1 NO_LIBBPF=1
+make_minimal        += NO_LIBBPF=1
 make_minimal        += NO_SDT=1 NO_JVMTI=1 NO_LIBZSTD=1
 make_minimal        += NO_LIBCAP=1 NO_CAPSTONE=1
 

tools/perf/util/Build

@@ -223,9 +223,8 @@ perf-util-$(CONFIG_LIBDW) += dwarf-regs-arch/
 perf-util-$(CONFIG_LIBDW) += debuginfo.o
 perf-util-$(CONFIG_LIBDW) += annotate-data.o
 perf-util-$(CONFIG_LIBDW) += libdw.o
+perf-util-$(CONFIG_LIBDW) += unwind-libdw.o
 
-perf-util-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o
-perf-util-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw-arch/
 perf-util-$(CONFIG_LOCAL_LIBUNWIND)    += unwind-libunwind-local.o
 perf-util-$(CONFIG_LIBUNWIND)          += unwind-libunwind.o
 perf-util-$(CONFIG_LIBUNWIND_X86)      += libunwind/x86_32.o