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

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

Note, the link register was being coped to DWARF register 65 that the
SysV ABI spec claims is FPSCR. It is corrected here to 108, but this is
unlikely to matter as FPSCR has little to no impact on unwinding.

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/dwarf-regs-powerpc.c

@@ -4,8 +4,9 @@
  *
  * Copyright (C) 2010 Ian Munsie, IBM Corporation.
  */
-
+#include <errno.h>
 #include <dwarf-regs.h>
+#include "../../../arch/powerpc/include/uapi/asm/perf_regs.h"
 
 #define PPC_OP(op)	(((op) >> 26) & 0x3F)
 #define PPC_RA(a)	(((a) >> 16) & 0x1f)
@@ -59,3 +60,77 @@ void get_powerpc_regs(u32 raw_insn, int is_source,
 	if ((op_loc->mem_ref) && (PPC_OP(raw_insn) != 31))
 		op_loc->offset = get_offset_opcode(raw_insn);
 }
+
+int __get_dwarf_regnum_for_perf_regnum_powerpc(int perf_regnum)
+{
+	static const int dwarf_powerpc_regnums[] = {
+		[PERF_REG_POWERPC_R0] = 0,
+		[PERF_REG_POWERPC_R1] = 1,
+		[PERF_REG_POWERPC_R2] = 2,
+		[PERF_REG_POWERPC_R3] = 3,
+		[PERF_REG_POWERPC_R4] = 4,
+		[PERF_REG_POWERPC_R5] = 5,
+		[PERF_REG_POWERPC_R6] = 6,
+		[PERF_REG_POWERPC_R7] = 7,
+		[PERF_REG_POWERPC_R8] = 8,
+		[PERF_REG_POWERPC_R9] = 9,
+		[PERF_REG_POWERPC_R10] = 10,
+		[PERF_REG_POWERPC_R11] = 11,
+		[PERF_REG_POWERPC_R12] = 12,
+		[PERF_REG_POWERPC_R13] = 13,
+		[PERF_REG_POWERPC_R14] = 14,
+		[PERF_REG_POWERPC_R15] = 15,
+		[PERF_REG_POWERPC_R16] = 16,
+		[PERF_REG_POWERPC_R17] = 17,
+		[PERF_REG_POWERPC_R18] = 18,
+		[PERF_REG_POWERPC_R19] = 19,
+		[PERF_REG_POWERPC_R20] = 20,
+		[PERF_REG_POWERPC_R21] = 21,
+		[PERF_REG_POWERPC_R22] = 22,
+		[PERF_REG_POWERPC_R23] = 23,
+		[PERF_REG_POWERPC_R24] = 24,
+		[PERF_REG_POWERPC_R25] = 25,
+		[PERF_REG_POWERPC_R26] = 26,
+		[PERF_REG_POWERPC_R27] = 27,
+		[PERF_REG_POWERPC_R28] = 28,
+		[PERF_REG_POWERPC_R29] = 29,
+		[PERF_REG_POWERPC_R30] = 30,
+		[PERF_REG_POWERPC_R31] = 31,
+		/* TODO: PERF_REG_POWERPC_NIP */
+		[PERF_REG_POWERPC_MSR] = 66,
+		/* TODO: PERF_REG_POWERPC_ORIG_R3 */
+		[PERF_REG_POWERPC_CTR] = 109,
+		[PERF_REG_POWERPC_LINK] = 108, /* Note, previously in perf encoded as 65? */
+		[PERF_REG_POWERPC_XER] = 101,
+		/* TODO: PERF_REG_POWERPC_CCR */
+		/* TODO: PERF_REG_POWERPC_SOFTE */
+		/* TODO: PERF_REG_POWERPC_TRAP */
+		/* TODO: PERF_REG_POWERPC_DAR */
+		/* TODO: PERF_REG_POWERPC_DSISR */
+		/* TODO: PERF_REG_POWERPC_SIER */
+		/* TODO: PERF_REG_POWERPC_MMCRA */
+		/* TODO: PERF_REG_POWERPC_MMCR0 */
+		/* TODO: PERF_REG_POWERPC_MMCR1 */
+		/* TODO: PERF_REG_POWERPC_MMCR2 */
+		/* TODO: PERF_REG_POWERPC_MMCR3 */
+		/* TODO: PERF_REG_POWERPC_SIER2 */
+		/* TODO: PERF_REG_POWERPC_SIER3 */
+		/* TODO: PERF_REG_POWERPC_PMC1 */
+		/* TODO: PERF_REG_POWERPC_PMC2 */
+		/* TODO: PERF_REG_POWERPC_PMC3 */
+		/* TODO: PERF_REG_POWERPC_PMC4 */
+		/* TODO: PERF_REG_POWERPC_PMC5 */
+		/* TODO: PERF_REG_POWERPC_PMC6 */
+		/* TODO: PERF_REG_POWERPC_SDAR */
+		/* TODO: PERF_REG_POWERPC_SIAR */
+	};
+
+	if (perf_regnum == 0)
+		return 0;
+
+	if (perf_regnum <  0 || perf_regnum > (int)ARRAY_SIZE(dwarf_powerpc_regnums) ||
+	    dwarf_powerpc_regnums[perf_regnum] == 0)
+		return -ENOENT;
+
+	return dwarf_powerpc_regnums[perf_regnum];
+}

tools/perf/util/dwarf-regs.c

@@ -205,6 +205,10 @@ int get_dwarf_regnum_for_perf_regnum(int perf_regnum, unsigned int machine,
 	case EM_CSKY:
 		reg = __get_dwarf_regnum_for_perf_regnum_csky(perf_regnum, flags);
 		break;
+	case EM_PPC:
+	case EM_PPC64:
+		reg = __get_dwarf_regnum_for_perf_regnum_powerpc(perf_regnum);
+		break;
 	case EM_LOONGARCH:
 		reg = __get_dwarf_regnum_for_perf_regnum_loongarch(perf_regnum);
 		break;

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

@@ -110,6 +110,7 @@ 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);
 
 /*
  * get_dwarf_regnum - Returns DWARF regnum from register name

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

@@ -1,3 +1,2 @@
-perf-util-y += unwind-libdw-powerpc.o
 perf-util-y += unwind-libdw-riscv.o
 perf-util-y += unwind-libdw-s390.o

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

@@ -292,15 +292,12 @@ static const Dwfl_Thread_Callbacks callbacks_generic = {
 	.set_initial_registers = libdw_set_initial_registers_generic,
 };
 
-DEFINE_DWFL_THREAD_CALLBACKS(powerpc);
 DEFINE_DWFL_THREAD_CALLBACKS(riscv);
 DEFINE_DWFL_THREAD_CALLBACKS(s390);
 
 static const Dwfl_Thread_Callbacks *get_thread_callbacks(const char *arch)
 {
-	if (!strcmp(arch, "powerpc"))
-		return &callbacks_powerpc;
-	else if (!strcmp(arch, "riscv"))
+	if (!strcmp(arch, "riscv"))
 		return &callbacks_riscv;
 	else if (!strcmp(arch, "s390"))
 		return &callbacks_s390;

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_powerpc(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);