perf dwarf-regs: Add RISC-V perf to DWARF register number mapping functions

These functions allow the generic initial register state code in
unwind-libdw to be used.

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/util/dwarf-regs-arch/Build

@@ -3,4 +3,5 @@ perf-util-$(CONFIG_LIBDW) += dwarf-regs-arm.o
 perf-util-$(CONFIG_LIBDW) += dwarf-regs-csky.o
 perf-util-$(CONFIG_LIBDW) += dwarf-regs-loongarch.o
 perf-util-$(CONFIG_LIBDW) += dwarf-regs-powerpc.o
+perf-util-$(CONFIG_LIBDW) += dwarf-regs-riscv.o
 perf-util-$(CONFIG_LIBDW) += dwarf-regs-x86.o

tools/perf/util/dwarf-regs-arch/dwarf-regs-riscv.c

@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <errno.h>
+#include <dwarf-regs.h>
+#include "../../../arch/riscv/include/uapi/asm/perf_regs.h"
+
+int __get_dwarf_regnum_for_perf_regnum_riscv(int perf_regnum)
+{
+	if (perf_regnum < 0 || perf_regnum >= PERF_REG_RISCV_MAX)
+		return -ENOENT;
+
+	return perf_regnum;
+}

tools/perf/util/dwarf-regs.c

@@ -209,6 +209,9 @@ int get_dwarf_regnum_for_perf_regnum(int perf_regnum, unsigned int machine,
 	case EM_PPC64:
 		reg = __get_dwarf_regnum_for_perf_regnum_powerpc(perf_regnum);
 		break;
+	case EM_RISCV:
+		reg = __get_dwarf_regnum_for_perf_regnum_riscv(perf_regnum);
+		break;
 	case EM_LOONGARCH:
 		reg = __get_dwarf_regnum_for_perf_regnum_loongarch(perf_regnum);
 		break;

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

@@ -111,6 +111,7 @@ int __get_dwarf_regnum_for_perf_regnum_arm64(int perf_regnum);
 int __get_dwarf_regnum_for_perf_regnum_csky(int perf_regnum, unsigned int flags);
 int __get_dwarf_regnum_for_perf_regnum_loongarch(int perf_regnum);
 int __get_dwarf_regnum_for_perf_regnum_powerpc(int perf_regnum);
+int __get_dwarf_regnum_for_perf_regnum_riscv(int perf_regnum);
 
 /*
  * get_dwarf_regnum - Returns DWARF regnum from register name

tools/perf/util/unwind-libdw-arch/Build

@@ -1,2 +1 @@
-perf-util-y += unwind-libdw-riscv.o
 perf-util-y += unwind-libdw-s390.o

tools/perf/util/unwind-libdw-arch/unwind-libdw-riscv.c

@@ -292,14 +292,11 @@ static const Dwfl_Thread_Callbacks callbacks_generic = {
 	.set_initial_registers = libdw_set_initial_registers_generic,
 };
 
-DEFINE_DWFL_THREAD_CALLBACKS(riscv);
 DEFINE_DWFL_THREAD_CALLBACKS(s390);
 
 static const Dwfl_Thread_Callbacks *get_thread_callbacks(const char *arch)
 {
-	if (!strcmp(arch, "riscv"))
-		return &callbacks_riscv;
-	else if (!strcmp(arch, "s390"))
+	if (!strcmp(arch, "s390"))
 		return &callbacks_s390;
 
 	return &callbacks_generic;

tools/perf/util/unwind-libdw.c

@@ -10,7 +10,6 @@ struct perf_sample;
 struct thread;
 
 bool libdw_set_initial_registers_mips(Dwfl_Thread *thread, void *arg);
-bool libdw_set_initial_registers_riscv(Dwfl_Thread *thread, void *arg);
 bool libdw_set_initial_registers_s390(Dwfl_Thread *thread, void *arg);
 
 struct unwind_info {