[PATCH 4/4] perf tools: Add libdw DWARF post unwind support for ARM

From: Jean Pihet
Date: Fri May 16 2014 - 04:41:47 EST


Adding libdw DWARF post unwind support, which is part
of elfutils-devel/libdw-dev package from version 0.158.

The new code is contained in unwin-libdw.c object, and
implements unwind__get_entries unwind interface function.

Signed-off-by: Jean Pihet <jean.pihet@xxxxxxxxxx>
Reviewed-by: Will Deacon <will.deacon@xxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Corey Ashford <cjashfor@xxxxxxxxxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
---
tools/perf/arch/arm/Makefile | 5 +++++
tools/perf/arch/arm/util/unwind-libdw.c | 36 +++++++++++++++++++++++++++++++++
2 files changed, 41 insertions(+)
create mode 100644 tools/perf/arch/arm/util/unwind-libdw.c

diff --git a/tools/perf/arch/arm/Makefile b/tools/perf/arch/arm/Makefile
index 221f21d..09d6215 100644
--- a/tools/perf/arch/arm/Makefile
+++ b/tools/perf/arch/arm/Makefile
@@ -4,6 +4,11 @@ LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/dwarf-regs.o
endif
ifndef NO_LIBUNWIND
LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/unwind-libunwind.o
+endif
+ifndef NO_LIBDW_DWARF_UNWIND
+LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/unwind-libdw.o
+endif
+ifndef NO_DWARF_UNWIND
LIB_OBJS += $(OUTPUT)arch/$(ARCH)/tests/regs_load.o
LIB_OBJS += $(OUTPUT)arch/$(ARCH)/tests/dwarf-unwind.o
endif
diff --git a/tools/perf/arch/arm/util/unwind-libdw.c b/tools/perf/arch/arm/util/unwind-libdw.c
new file mode 100644
index 0000000..b4176c6
--- /dev/null
+++ b/tools/perf/arch/arm/util/unwind-libdw.c
@@ -0,0 +1,36 @@
+#include <elfutils/libdwfl.h>
+#include "../../util/unwind-libdw.h"
+#include "../../util/perf_regs.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_ARM_MAX];
+
+#define REG(r) ({ \
+ Dwarf_Word val = 0; \
+ perf_reg_value(&val, user_regs, PERF_REG_ARM_##r); \
+ val; \
+})
+
+ dwarf_regs[0] = REG(R0);
+ dwarf_regs[1] = REG(R1);
+ dwarf_regs[2] = REG(R2);
+ dwarf_regs[3] = REG(R3);
+ dwarf_regs[4] = REG(R4);
+ dwarf_regs[5] = REG(R5);
+ dwarf_regs[6] = REG(R6);
+ dwarf_regs[7] = REG(R7);
+ dwarf_regs[8] = REG(R8);
+ dwarf_regs[9] = REG(R9);
+ dwarf_regs[10] = REG(R10);
+ dwarf_regs[11] = REG(FP);
+ dwarf_regs[12] = REG(IP);
+ dwarf_regs[13] = REG(SP);
+ dwarf_regs[14] = REG(LR);
+ dwarf_regs[15] = REG(PC);
+
+ return dwfl_thread_state_registers(thread, 0, PERF_REG_ARM_MAX,
+ dwarf_regs);
+}
--
1.7.11.7

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