csky: Add support for perf unwind-libdw

This patch add support for DWARF register mappings and libdw registers
initialization, which is used by perf callchain analyzing, eg:

perf record --call-graph=dwarf <COMMAND>

Here is elfutils csky backend patch set:
https://sourceware.org/ml/elfutils-devel/2019-q2/msg00007.html

Signed-off-by: Mao Han <han_mao@c-sky.com>
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnd Bergmann <arnd@arnd.de>

1 files changed, 77 insertions, 0 deletions

diff --git a/tools/perf/arch/csky/util/unwind-libdw.c b/tools/perf/arch/csky/util/unwind-libdw.c
new file mode 100644
index 000000000000..4bb4a06776e4
--- /dev/null
+++ b/tools/perf/arch/csky/util/unwind-libdw.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2019 Hangzhou C-SKY Microsystems co.,ltd.
+
+#include <elfutils/libdwfl.h>
+#include "../../util/unwind-libdw.h"
+#include "../../util/perf_regs.h"
+#include "../../util/event.h"
+
+bool libdw__arch_set_initial_registers(Dwfl_Thread *thread, void *arg)
+{
+	struct unwind_info *ui = arg;
+	struct regs_dump *user_regs = &ui->sample->user_regs;
+	Dwarf_Word dwarf_regs[PERF_REG_CSKY_MAX];
+
+#define REG(r) ({						\
+	Dwarf_Word val = 0;					\
+	perf_reg_value(&val, user_regs, PERF_REG_CSKY_##r);	\
+	val;							\
+})
+
+#if defined(__CSKYABIV2__)
+	dwarf_regs[0]  = REG(A0);
+	dwarf_regs[1]  = REG(A1);
+	dwarf_regs[2]  = REG(A2);
+	dwarf_regs[3]  = REG(A3);
+	dwarf_regs[4]  = REG(REGS0);
+	dwarf_regs[5]  = REG(REGS1);
+	dwarf_regs[6]  = REG(REGS2);
+	dwarf_regs[7]  = REG(REGS3);
+	dwarf_regs[8]  = REG(REGS4);
+	dwarf_regs[9]  = REG(REGS5);
+	dwarf_regs[10] = REG(REGS6);
+	dwarf_regs[11] = REG(REGS7);
+	dwarf_regs[12] = REG(REGS8);
+	dwarf_regs[13] = REG(REGS9);
+	dwarf_regs[14] = REG(SP);
+	dwarf_regs[15] = REG(LR);
+	dwarf_regs[16] = REG(EXREGS0);
+	dwarf_regs[17] = REG(EXREGS1);
+	dwarf_regs[18] = REG(EXREGS2);
+	dwarf_regs[19] = REG(EXREGS3);
+	dwarf_regs[20] = REG(EXREGS4);
+	dwarf_regs[21] = REG(EXREGS5);
+	dwarf_regs[22] = REG(EXREGS6);
+	dwarf_regs[23] = REG(EXREGS7);
+	dwarf_regs[24] = REG(EXREGS8);
+	dwarf_regs[25] = REG(EXREGS9);
+	dwarf_regs[26] = REG(EXREGS10);
+	dwarf_regs[27] = REG(EXREGS11);
+	dwarf_regs[28] = REG(EXREGS12);
+	dwarf_regs[29] = REG(EXREGS13);
+	dwarf_regs[30] = REG(EXREGS14);
+	dwarf_regs[31] = REG(TLS);
+	dwarf_regs[32] = REG(PC);
+#else
+	dwarf_regs[0]  = REG(SP);
+	dwarf_regs[1]  = REG(REGS9);
+	dwarf_regs[2]  = REG(A0);
+	dwarf_regs[3]  = REG(A1);
+	dwarf_regs[4]  = REG(A2);
+	dwarf_regs[5]  = REG(A3);
+	dwarf_regs[6]  = REG(REGS0);
+	dwarf_regs[7]  = REG(REGS1);
+	dwarf_regs[8]  = REG(REGS2);
+	dwarf_regs[9]  = REG(REGS3);
+	dwarf_regs[10] = REG(REGS4);
+	dwarf_regs[11] = REG(REGS5);
+	dwarf_regs[12] = REG(REGS6);
+	dwarf_regs[13] = REG(REGS7);
+	dwarf_regs[14] = REG(REGS8);
+	dwarf_regs[15] = REG(LR);
+#endif
+	dwfl_thread_state_register_pc(thread, REG(PC));
+
+	return dwfl_thread_state_registers(thread, 0, PERF_REG_CSKY_MAX,
+					   dwarf_regs);
+}