[PATCH V3 3/3] riscv: Add support for libdw

From: Mao Han
Date: Fri May 17 2019 - 04:47:36 EST

This patch add support for DWARF register mappings and libdw registers
initialization, which is used by perf callchain analyzing when
--call-graph=dwarf is given.

Signed-off-by: Mao Han <han_mao@xxxxxxxxx>
CC: Palmer Dabbelt <palmer@xxxxxxxxxx>
CC: linux-riscv <linux-riscv@xxxxxxxxxxxxxxxxxxx>
CC: Christoph Hellwig <hch@xxxxxx>
CC: Guo Ren <guoren@xxxxxxxxxx>
---
tools/arch/riscv/include/uapi/asm/perf_regs.h | 42 ++++++++++++
tools/perf/Makefile.config | 6 +-
tools/perf/arch/riscv/Build | 1 +
tools/perf/arch/riscv/Makefile | 3 +
tools/perf/arch/riscv/include/perf_regs.h | 96 +++++++++++++++++++++++++++
tools/perf/arch/riscv/util/Build | 2 +
tools/perf/arch/riscv/util/dwarf-regs.c | 72 ++++++++++++++++++++
tools/perf/arch/riscv/util/unwind-libdw.c | 57 ++++++++++++++++
8 files changed, 278 insertions(+), 1 deletion(-)
create mode 100644 tools/arch/riscv/include/uapi/asm/perf_regs.h
create mode 100644 tools/perf/arch/riscv/Build
create mode 100644 tools/perf/arch/riscv/Makefile
create mode 100644 tools/perf/arch/riscv/include/perf_regs.h
create mode 100644 tools/perf/arch/riscv/util/Build
create mode 100644 tools/perf/arch/riscv/util/dwarf-regs.c
create mode 100644 tools/perf/arch/riscv/util/unwind-libdw.c

diff --git a/tools/arch/riscv/include/uapi/asm/perf_regs.h b/tools/arch/riscv/include/uapi/asm/perf_regs.h
new file mode 100644
index 0000000..df1a581
--- /dev/null
+++ b/tools/arch/riscv/include/uapi/asm/perf_regs.h
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2019 Hangzhou C-SKY Microsystems co.,ltd. */
+
+#ifndef _ASM_RISCV_PERF_REGS_H
+#define _ASM_RISCV_PERF_REGS_H
+
+enum perf_event_riscv_regs {
+ PERF_REG_RISCV_PC,
+ PERF_REG_RISCV_RA,
+ PERF_REG_RISCV_SP,
+ PERF_REG_RISCV_GP,
+ PERF_REG_RISCV_TP,
+ PERF_REG_RISCV_T0,
+ PERF_REG_RISCV_T1,
+ PERF_REG_RISCV_T2,
+ PERF_REG_RISCV_S0,
+ PERF_REG_RISCV_S1,
+ PERF_REG_RISCV_A0,
+ PERF_REG_RISCV_A1,
+ PERF_REG_RISCV_A2,
+ PERF_REG_RISCV_A3,
+ PERF_REG_RISCV_A4,
+ PERF_REG_RISCV_A5,
+ PERF_REG_RISCV_A6,
+ PERF_REG_RISCV_A7,
+ PERF_REG_RISCV_S2,
+ PERF_REG_RISCV_S3,
+ PERF_REG_RISCV_S4,
+ PERF_REG_RISCV_S5,
+ PERF_REG_RISCV_S6,
+ PERF_REG_RISCV_S7,
+ PERF_REG_RISCV_S8,
+ PERF_REG_RISCV_S9,
+ PERF_REG_RISCV_S10,
+ PERF_REG_RISCV_S11,
+ PERF_REG_RISCV_T3,
+ PERF_REG_RISCV_T4,
+ PERF_REG_RISCV_T5,
+ PERF_REG_RISCV_T6,
+ PERF_REG_RISCV_MAX,
+};
+#endif /* _ASM_RISCV_PERF_REGS_H */
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index fe3f97e..8f2e6d3 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -59,6 +59,10 @@ ifeq ($(SRCARCH),arm64)
LIBUNWIND_LIBS = -lunwind -lunwind-aarch64
endif

+ifeq ($(SRCARCH),riscv)
+ NO_PERF_REGS := 0
+endif
+
ifeq ($(ARCH),s390)
NO_PERF_REGS := 0
NO_SYSCALL_TABLE := 0
@@ -77,7 +81,7 @@ endif
# Disable it on all other architectures in case libdw unwind
# support is detected in system. Add supported architectures
# to the check.
-ifneq ($(SRCARCH),$(filter $(SRCARCH),x86 arm arm64 powerpc s390))
+ifneq ($(SRCARCH),$(filter $(SRCARCH),x86 arm arm64 powerpc s390 riscv))
NO_LIBDW_DWARF_UNWIND := 1
endif

diff --git a/tools/perf/arch/riscv/Build b/tools/perf/arch/riscv/Build
new file mode 100644
index 0000000..e4e5f33
--- /dev/null
+++ b/tools/perf/arch/riscv/Build
@@ -0,0 +1 @@
+perf-y += util/
diff --git a/tools/perf/arch/riscv/Makefile b/tools/perf/arch/riscv/Makefile
new file mode 100644
index 0000000..7fbca17
--- /dev/null
+++ b/tools/perf/arch/riscv/Makefile
@@ -0,0 +1,3 @@
+ifndef NO_DWARF
+PERF_HAVE_DWARF_REGS := 1
+endif
diff --git a/tools/perf/arch/riscv/include/perf_regs.h b/tools/perf/arch/riscv/include/perf_regs.h
new file mode 100644
index 0000000..7a8bcde
--- /dev/null
+++ b/tools/perf/arch/riscv/include/perf_regs.h
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2019 Hangzhou C-SKY Microsystems co.,ltd. */
+
+#ifndef ARCH_PERF_REGS_H
+#define ARCH_PERF_REGS_H
+
+#include <stdlib.h>
+#include <linux/types.h>
+#include <asm/perf_regs.h>
+
+#define PERF_REGS_MASK ((1ULL << PERF_REG_RISCV_MAX) - 1)
+#define PERF_REGS_MAX PERF_REG_RISCV_MAX
+#if __riscv_xlen == 64
+#define PERF_SAMPLE_REGS_ABI PERF_SAMPLE_REGS_ABI_64
+#else
+#define PERF_SAMPLE_REGS_ABI PERF_SAMPLE_REGS_ABI_32
+#endif
+
+#define PERF_REG_IP PERF_REG_RISCV_PC
+#define PERF_REG_SP PERF_REG_RISCV_SP
+
+static inline const char *perf_reg_name(int id)
+{
+ switch (id) {
+ case PERF_REG_RISCV_PC:
+ return "pc";
+ case PERF_REG_RISCV_RA:
+ return "ra";
+ case PERF_REG_RISCV_SP:
+ return "sp";
+ case PERF_REG_RISCV_GP:
+ return "gp";
+ case PERF_REG_RISCV_TP:
+ return "tp";
+ case PERF_REG_RISCV_T0:
+ return "t0";
+ case PERF_REG_RISCV_T1:
+ return "t1";
+ case PERF_REG_RISCV_T2:
+ return "t2";
+ case PERF_REG_RISCV_S0:
+ return "s0";
+ case PERF_REG_RISCV_S1:
+ return "s1";
+ case PERF_REG_RISCV_A0:
+ return "a0";
+ case PERF_REG_RISCV_A1:
+ return "a1";
+ case PERF_REG_RISCV_A2:
+ return "a2";
+ case PERF_REG_RISCV_A3:
+ return "a3";
+ case PERF_REG_RISCV_A4:
+ return "a4";
+ case PERF_REG_RISCV_A5:
+ return "a5";
+ case PERF_REG_RISCV_A6:
+ return "a6";
+ case PERF_REG_RISCV_A7:
+ return "a7";
+ case PERF_REG_RISCV_S2:
+ return "s2";
+ case PERF_REG_RISCV_S3:
+ return "s3";
+ case PERF_REG_RISCV_S4:
+ return "s4";
+ case PERF_REG_RISCV_S5:
+ return "s5";
+ case PERF_REG_RISCV_S6:
+ return "s6";
+ case PERF_REG_RISCV_S7:
+ return "s7";
+ case PERF_REG_RISCV_S8:
+ return "s8";
+ case PERF_REG_RISCV_S9:
+ return "s9";
+ case PERF_REG_RISCV_S10:
+ return "s10";
+ case PERF_REG_RISCV_S11:
+ return "s11";
+ case PERF_REG_RISCV_T3:
+ return "t3";
+ case PERF_REG_RISCV_T4:
+ return "t4";
+ case PERF_REG_RISCV_T5:
+ return "t5";
+ case PERF_REG_RISCV_T6:
+ return "t6";
+ default:
+ return NULL;
+ }
+
+ return NULL;
+}
+
+#endif /* ARCH_PERF_REGS_H */
diff --git a/tools/perf/arch/riscv/util/Build b/tools/perf/arch/riscv/util/Build
new file mode 100644
index 0000000..1160bb2
--- /dev/null
+++ b/tools/perf/arch/riscv/util/Build
@@ -0,0 +1,2 @@
+perf-$(CONFIG_DWARF) += dwarf-regs.o
+perf-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o
diff --git a/tools/perf/arch/riscv/util/dwarf-regs.c b/tools/perf/arch/riscv/util/dwarf-regs.c
new file mode 100644
index 0000000..f3555f6
--- /dev/null
+++ b/tools/perf/arch/riscv/util/dwarf-regs.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Hangzhou C-SKY Microsystems co.,ltd.
+ * Mapping of DWARF debug register numbers into register names.
+ */
+
+#include <stddef.h>
+#include <errno.h> /* for EINVAL */
+#include <string.h> /* for strcmp */
+#include <dwarf-regs.h>
+
+struct pt_regs_dwarfnum {
+ const char *name;
+ unsigned int dwarfnum;
+};
+
+#define REG_DWARFNUM_NAME(r, num) {.name = r, .dwarfnum = num}
+#define REG_DWARFNUM_END {.name = NULL, .dwarfnum = 0}
+
+struct pt_regs_dwarfnum riscv_dwarf_regs_table[] = {
+ REG_DWARFNUM_NAME("%zero", 0),
+ REG_DWARFNUM_NAME("%ra", 1),
+ REG_DWARFNUM_NAME("%sp", 2),
+ REG_DWARFNUM_NAME("%gp", 3),
+ REG_DWARFNUM_NAME("%tp", 4),
+ REG_DWARFNUM_NAME("%t0", 5),
+ REG_DWARFNUM_NAME("%t1", 6),
+ REG_DWARFNUM_NAME("%t2", 7),
+ REG_DWARFNUM_NAME("%s0", 8),
+ REG_DWARFNUM_NAME("%s1", 9),
+ REG_DWARFNUM_NAME("%a0", 10),
+ REG_DWARFNUM_NAME("%a1", 11),
+ REG_DWARFNUM_NAME("%a2", 12),
+ REG_DWARFNUM_NAME("%a3", 13),
+ REG_DWARFNUM_NAME("%a4", 14),
+ REG_DWARFNUM_NAME("%a5", 15),
+ REG_DWARFNUM_NAME("%a6", 16),
+ REG_DWARFNUM_NAME("%a7", 17),
+ REG_DWARFNUM_NAME("%s2", 18),
+ REG_DWARFNUM_NAME("%s3", 19),
+ REG_DWARFNUM_NAME("%s4", 20),
+ REG_DWARFNUM_NAME("%s5", 21),
+ REG_DWARFNUM_NAME("%s6", 22),
+ REG_DWARFNUM_NAME("%s7", 23),
+ REG_DWARFNUM_NAME("%s8", 24),
+ REG_DWARFNUM_NAME("%s9", 25),
+ REG_DWARFNUM_NAME("%s10", 26),
+ REG_DWARFNUM_NAME("%s11", 27),
+ REG_DWARFNUM_NAME("%t3", 28),
+ REG_DWARFNUM_NAME("%t4", 29),
+ REG_DWARFNUM_NAME("%t5", 30),
+ REG_DWARFNUM_NAME("%t6", 31),
+ REG_DWARFNUM_END,
+};
+
+#define RISCV_MAX_REGS ((sizeof(riscv_dwarf_regs_table) / \
+ sizeof(riscv_dwarf_regs_table[0])) - 1)
+
+const char *get_arch_regstr(unsigned int n)
+{
+ return (n < RISCV_MAX_REGS) ? riscv_dwarf_regs_table[n].name : NULL;
+}
+
+int regs_query_register_offset(const char *name)
+{
+ const struct pt_regs_dwarfnum *roff;
+
+ for (roff = riscv_dwarf_regs_table; roff->name != NULL; roff++)
+ if (!strcmp(roff->name, name))
+ return roff->dwarfnum;
+ return -EINVAL;
+}
diff --git a/tools/perf/arch/riscv/util/unwind-libdw.c b/tools/perf/arch/riscv/util/unwind-libdw.c
new file mode 100644
index 0000000..19536e1
--- /dev/null
+++ b/tools/perf/arch/riscv/util/unwind-libdw.c
@@ -0,0 +1,57 @@
+// 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[32];
+
+#define REG(r) ({ \
+ Dwarf_Word val = 0; \
+ perf_reg_value(&val, user_regs, PERF_REG_RISCV_##r); \
+ val; \
+})
+
+ dwarf_regs[0] = 0;
+ dwarf_regs[1] = REG(RA);
+ dwarf_regs[2] = REG(SP);
+ dwarf_regs[3] = REG(GP);
+ dwarf_regs[4] = REG(TP);
+ dwarf_regs[5] = REG(T0);
+ dwarf_regs[6] = REG(T1);
+ dwarf_regs[7] = REG(T2);
+ dwarf_regs[8] = REG(S0);
+ dwarf_regs[9] = REG(S1);
+ dwarf_regs[10] = REG(A0);
+ dwarf_regs[11] = REG(A1);
+ dwarf_regs[12] = REG(A2);
+ dwarf_regs[13] = REG(A3);
+ dwarf_regs[14] = REG(A4);
+ dwarf_regs[15] = REG(A5);
+ dwarf_regs[16] = REG(A6);
+ dwarf_regs[17] = REG(A7);
+ dwarf_regs[18] = REG(S2);
+ dwarf_regs[19] = REG(S3);
+ dwarf_regs[20] = REG(S4);
+ dwarf_regs[21] = REG(S5);
+ dwarf_regs[22] = REG(S6);
+ dwarf_regs[23] = REG(S7);
+ dwarf_regs[24] = REG(S8);
+ dwarf_regs[25] = REG(S9);
+ dwarf_regs[26] = REG(S10);
+ dwarf_regs[27] = REG(S11);
+ dwarf_regs[28] = REG(T3);
+ dwarf_regs[29] = REG(T4);
+ dwarf_regs[30] = REG(T5);
+ dwarf_regs[31] = REG(T6);
+ dwfl_thread_state_register_pc(thread, REG(PC));
+
+ return dwfl_thread_state_registers(thread, 0, PERF_REG_RISCV_MAX,
+ dwarf_regs);
+}
--
2.7.4