[PATCH 09/16] perf tools: Separate libunwind code to special object

[Jiri Olsa <jolsa@redhat.com>]

We are going to add libdw library support to do dwarf
post unwind.

Making the code ready by moving libunwind dwarf post
unwind stuff into separate object.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jean Pihet <jean.pihet@linaro.org>
---
 tools/perf/Makefile.perf                    |   2 +-
 tools/perf/arch/arm/Makefile                |   2 +-
 tools/perf/arch/arm/util/unwind-libunwind.c |  48 +++
 tools/perf/arch/arm/util/unwind.c           |  48 ---
 tools/perf/arch/x86/Makefile                |   2 +-
 tools/perf/arch/x86/util/unwind-libunwind.c | 111 +++++
 tools/perf/arch/x86/util/unwind.c           | 111 -----
 tools/perf/util/unwind-libunwind.c          | 611 ++++++++++++++++++++++++++++
 tools/perf/util/unwind.c                    | 611 ----------------------------
 9 files changed, 773 insertions(+), 773 deletions(-)
 create mode 100644 tools/perf/arch/arm/util/unwind-libunwind.c
 delete mode 100644 tools/perf/arch/arm/util/unwind.c
 create mode 100644 tools/perf/arch/x86/util/unwind-libunwind.c
 delete mode 100644 tools/perf/arch/x86/util/unwind.c
 create mode 100644 tools/perf/util/unwind-libunwind.c
 delete mode 100644 tools/perf/util/unwind.c

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index eb39519..29e7e2b 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -480,7 +480,7 @@ endif # NO_DWARF
 endif # NO_LIBELF
 
 ifndef NO_LIBUNWIND
-  LIB_OBJS += $(OUTPUT)util/unwind.o
+  LIB_OBJS += $(OUTPUT)util/unwind-libunwind.o
 endif
 LIB_OBJS += $(OUTPUT)tests/keep-tracking.o
 
diff --git a/tools/perf/arch/arm/Makefile b/tools/perf/arch/arm/Makefile
index fe9b61e..67e9b3d 100644
--- a/tools/perf/arch/arm/Makefile
+++ b/tools/perf/arch/arm/Makefile
@@ -3,5 +3,5 @@ PERF_HAVE_DWARF_REGS := 1
 LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/dwarf-regs.o
 endif
 ifndef NO_LIBUNWIND
-LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/unwind.o
+LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/unwind-libunwind.o
 endif
diff --git a/tools/perf/arch/arm/util/unwind-libunwind.c b/tools/perf/arch/arm/util/unwind-libunwind.c
new file mode 100644
index 0000000..da3dc95
--- /dev/null
+++ b/tools/perf/arch/arm/util/unwind-libunwind.c
@@ -0,0 +1,48 @@
+
+#include <errno.h>
+#include <libunwind.h>
+#include "perf_regs.h"
+#include "../../util/unwind.h"
+
+int unwind__arch_reg_id(int regnum)
+{
+	switch (regnum) {
+	case UNW_ARM_R0:
+		return PERF_REG_ARM_R0;
+	case UNW_ARM_R1:
+		return PERF_REG_ARM_R1;
+	case UNW_ARM_R2:
+		return PERF_REG_ARM_R2;
+	case UNW_ARM_R3:
+		return PERF_REG_ARM_R3;
+	case UNW_ARM_R4:
+		return PERF_REG_ARM_R4;
+	case UNW_ARM_R5:
+		return PERF_REG_ARM_R5;
+	case UNW_ARM_R6:
+		return PERF_REG_ARM_R6;
+	case UNW_ARM_R7:
+		return PERF_REG_ARM_R7;
+	case UNW_ARM_R8:
+		return PERF_REG_ARM_R8;
+	case UNW_ARM_R9:
+		return PERF_REG_ARM_R9;
+	case UNW_ARM_R10:
+		return PERF_REG_ARM_R10;
+	case UNW_ARM_R11:
+		return PERF_REG_ARM_FP;
+	case UNW_ARM_R12:
+		return PERF_REG_ARM_IP;
+	case UNW_ARM_R13:
+		return PERF_REG_ARM_SP;
+	case UNW_ARM_R14:
+		return PERF_REG_ARM_LR;
+	case UNW_ARM_R15:
+		return PERF_REG_ARM_PC;
+	default:
+		pr_err("unwind: invalid reg id %d\n", regnum);
+		return -EINVAL;
+	}
+
+	return -EINVAL;
+}
diff --git a/tools/perf/arch/arm/util/unwind.c b/tools/perf/arch/arm/util/unwind.c
deleted file mode 100644
index da3dc95..0000000
--- a/tools/perf/arch/arm/util/unwind.c
+++ /dev/null
@@ -1,48 +0,0 @@
-
-#include <errno.h>
-#include <libunwind.h>
-#include "perf_regs.h"
-#include "../../util/unwind.h"
-
-int unwind__arch_reg_id(int regnum)
-{
-	switch (regnum) {
-	case UNW_ARM_R0:
-		return PERF_REG_ARM_R0;
-	case UNW_ARM_R1:
-		return PERF_REG_ARM_R1;
-	case UNW_ARM_R2:
-		return PERF_REG_ARM_R2;
-	case UNW_ARM_R3:
-		return PERF_REG_ARM_R3;
-	case UNW_ARM_R4:
-		return PERF_REG_ARM_R4;
-	case UNW_ARM_R5:
-		return PERF_REG_ARM_R5;
-	case UNW_ARM_R6:
-		return PERF_REG_ARM_R6;
-	case UNW_ARM_R7:
-		return PERF_REG_ARM_R7;
-	case UNW_ARM_R8:
-		return PERF_REG_ARM_R8;
-	case UNW_ARM_R9:
-		return PERF_REG_ARM_R9;
-	case UNW_ARM_R10:
-		return PERF_REG_ARM_R10;
-	case UNW_ARM_R11:
-		return PERF_REG_ARM_FP;
-	case UNW_ARM_R12:
-		return PERF_REG_ARM_IP;
-	case UNW_ARM_R13:
-		return PERF_REG_ARM_SP;
-	case UNW_ARM_R14:
-		return PERF_REG_ARM_LR;
-	case UNW_ARM_R15:
-		return PERF_REG_ARM_PC;
-	default:
-		pr_err("unwind: invalid reg id %d\n", regnum);
-		return -EINVAL;
-	}
-
-	return -EINVAL;
-}
diff --git a/tools/perf/arch/x86/Makefile b/tools/perf/arch/x86/Makefile
index 948ea6c..4fa9be9 100644
--- a/tools/perf/arch/x86/Makefile
+++ b/tools/perf/arch/x86/Makefile
@@ -3,7 +3,7 @@ PERF_HAVE_DWARF_REGS := 1
 LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/dwarf-regs.o
 endif
 ifndef NO_LIBUNWIND
-LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/unwind.o
+LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/unwind-libunwind.o
 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/x86/util/unwind-libunwind.c b/tools/perf/arch/x86/util/unwind-libunwind.c
new file mode 100644
index 0000000..456a88c
--- /dev/null
+++ b/tools/perf/arch/x86/util/unwind-libunwind.c
@@ -0,0 +1,111 @@
+
+#include <errno.h>
+#include <libunwind.h>
+#include "perf_regs.h"
+#include "../../util/unwind.h"
+
+#ifdef HAVE_ARCH_X86_64_SUPPORT
+int unwind__arch_reg_id(int regnum)
+{
+	int id;
+
+	switch (regnum) {
+	case UNW_X86_64_RAX:
+		id = PERF_REG_X86_AX;
+		break;
+	case UNW_X86_64_RDX:
+		id = PERF_REG_X86_DX;
+		break;
+	case UNW_X86_64_RCX:
+		id = PERF_REG_X86_CX;
+		break;
+	case UNW_X86_64_RBX:
+		id = PERF_REG_X86_BX;
+		break;
+	case UNW_X86_64_RSI:
+		id = PERF_REG_X86_SI;
+		break;
+	case UNW_X86_64_RDI:
+		id = PERF_REG_X86_DI;
+		break;
+	case UNW_X86_64_RBP:
+		id = PERF_REG_X86_BP;
+		break;
+	case UNW_X86_64_RSP:
+		id = PERF_REG_X86_SP;
+		break;
+	case UNW_X86_64_R8:
+		id = PERF_REG_X86_R8;
+		break;
+	case UNW_X86_64_R9:
+		id = PERF_REG_X86_R9;
+		break;
+	case UNW_X86_64_R10:
+		id = PERF_REG_X86_R10;
+		break;
+	case UNW_X86_64_R11:
+		id = PERF_REG_X86_R11;
+		break;
+	case UNW_X86_64_R12:
+		id = PERF_REG_X86_R12;
+		break;
+	case UNW_X86_64_R13:
+		id = PERF_REG_X86_R13;
+		break;
+	case UNW_X86_64_R14:
+		id = PERF_REG_X86_R14;
+		break;
+	case UNW_X86_64_R15:
+		id = PERF_REG_X86_R15;
+		break;
+	case UNW_X86_64_RIP:
+		id = PERF_REG_X86_IP;
+		break;
+	default:
+		pr_err("unwind: invalid reg id %d\n", regnum);
+		return -EINVAL;
+	}
+
+	return id;
+}
+#else
+int unwind__arch_reg_id(int regnum)
+{
+	int id;
+
+	switch (regnum) {
+	case UNW_X86_EAX:
+		id = PERF_REG_X86_AX;
+		break;
+	case UNW_X86_EDX:
+		id = PERF_REG_X86_DX;
+		break;
+	case UNW_X86_ECX:
+		id = PERF_REG_X86_CX;
+		break;
+	case UNW_X86_EBX:
+		id = PERF_REG_X86_BX;
+		break;
+	case UNW_X86_ESI:
+		id = PERF_REG_X86_SI;
+		break;
+	case UNW_X86_EDI:
+		id = PERF_REG_X86_DI;
+		break;
+	case UNW_X86_EBP:
+		id = PERF_REG_X86_BP;
+		break;
+	case UNW_X86_ESP:
+		id = PERF_REG_X86_SP;
+		break;
+	case UNW_X86_EIP:
+		id = PERF_REG_X86_IP;
+		break;
+	default:
+		pr_err("unwind: invalid reg id %d\n", regnum);
+		return -EINVAL;
+	}
+
+	return id;
+}
+#endif /* HAVE_ARCH_X86_64_SUPPORT */
diff --git a/tools/perf/arch/x86/util/unwind.c b/tools/perf/arch/x86/util/unwind.c
deleted file mode 100644
index 456a88c..0000000
--- a/tools/perf/arch/x86/util/unwind.c
+++ /dev/null
@@ -1,111 +0,0 @@
-
-#include <errno.h>
-#include <libunwind.h>
-#include "perf_regs.h"
-#include "../../util/unwind.h"
-
-#ifdef HAVE_ARCH_X86_64_SUPPORT
-int unwind__arch_reg_id(int regnum)
-{
-	int id;
-
-	switch (regnum) {
-	case UNW_X86_64_RAX:
-		id = PERF_REG_X86_AX;
-		break;
-	case UNW_X86_64_RDX:
-		id = PERF_REG_X86_DX;
-		break;
-	case UNW_X86_64_RCX:
-		id = PERF_REG_X86_CX;
-		break;
-	case UNW_X86_64_RBX:
-		id = PERF_REG_X86_BX;
-		break;
-	case UNW_X86_64_RSI:
-		id = PERF_REG_X86_SI;
-		break;
-	case UNW_X86_64_RDI:
-		id = PERF_REG_X86_DI;
-		break;
-	case UNW_X86_64_RBP:
-		id = PERF_REG_X86_BP;
-		break;
-	case UNW_X86_64_RSP:
-		id = PERF_REG_X86_SP;
-		break;
-	case UNW_X86_64_R8:
-		id = PERF_REG_X86_R8;
-		break;
-	case UNW_X86_64_R9:
-		id = PERF_REG_X86_R9;
-		break;
-	case UNW_X86_64_R10:
-		id = PERF_REG_X86_R10;
-		break;
-	case UNW_X86_64_R11:
-		id = PERF_REG_X86_R11;
-		break;
-	case UNW_X86_64_R12:
-		id = PERF_REG_X86_R12;
-		break;
-	case UNW_X86_64_R13:
-		id = PERF_REG_X86_R13;
-		break;
-	case UNW_X86_64_R14:
-		id = PERF_REG_X86_R14;
-		break;
-	case UNW_X86_64_R15:
-		id = PERF_REG_X86_R15;
-		break;
-	case UNW_X86_64_RIP:
-		id = PERF_REG_X86_IP;
-		break;
-	default:
-		pr_err("unwind: invalid reg id %d\n", regnum);
-		return -EINVAL;
-	}
-
-	return id;
-}
-#else
-int unwind__arch_reg_id(int regnum)
-{
-	int id;
-
-	switch (regnum) {
-	case UNW_X86_EAX:
-		id = PERF_REG_X86_AX;
-		break;
-	case UNW_X86_EDX:
-		id = PERF_REG_X86_DX;
-		break;
-	case UNW_X86_ECX:
-		id = PERF_REG_X86_CX;
-		break;
-	case UNW_X86_EBX:
-		id = PERF_REG_X86_BX;
-		break;
-	case UNW_X86_ESI:
-		id = PERF_REG_X86_SI;
-		break;
-	case UNW_X86_EDI:
-		id = PERF_REG_X86_DI;
-		break;
-	case UNW_X86_EBP:
-		id = PERF_REG_X86_BP;
-		break;
-	case UNW_X86_ESP:
-		id = PERF_REG_X86_SP;
-		break;
-	case UNW_X86_EIP:
-		id = PERF_REG_X86_IP;
-		break;
-	default:
-		pr_err("unwind: invalid reg id %d\n", regnum);
-		return -EINVAL;
-	}
-
-	return id;
-}
-#endif /* HAVE_ARCH_X86_64_SUPPORT */
diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
new file mode 100644
index 0000000..226586e
--- /dev/null
+++ b/tools/perf/util/unwind-libunwind.c
@@ -0,0 +1,611 @@
+/*
+ * Post mortem Dwarf CFI based unwinding on top of regs and stack dumps.
+ *
+ * Lots of this code have been borrowed or heavily inspired from parts of
+ * the libunwind 0.99 code which are (amongst other contributors I may have
+ * forgotten):
+ *
+ * Copyright (C) 2002-2007 Hewlett-Packard Co
+ *	Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+ *
+ * And the bugs have been added by:
+ *
+ * Copyright (C) 2010, Frederic Weisbecker <fweisbec@gmail.com>
+ * Copyright (C) 2012, Jiri Olsa <jolsa@redhat.com>
+ *
+ */
+
+#include <elf.h>
+#include <gelf.h>
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <linux/list.h>
+#include <libunwind.h>
+#include <libunwind-ptrace.h>
+#include "thread.h"
+#include "session.h"
+#include "perf_regs.h"
+#include "unwind.h"
+#include "util.h"
+
+extern int
+UNW_OBJ(dwarf_search_unwind_table) (unw_addr_space_t as,
+				    unw_word_t ip,
+				    unw_dyn_info_t *di,
+				    unw_proc_info_t *pi,
+				    int need_unwind_info, void *arg);
+
+#define dwarf_search_unwind_table UNW_OBJ(dwarf_search_unwind_table)
+
+extern int
+UNW_OBJ(dwarf_find_debug_frame) (int found, unw_dyn_info_t *di_debug,
+				 unw_word_t ip,
+				 unw_word_t segbase,
+				 const char *obj_name, unw_word_t start,
+				 unw_word_t end);
+
+#define dwarf_find_debug_frame UNW_OBJ(dwarf_find_debug_frame)
+
+#define DW_EH_PE_FORMAT_MASK	0x0f	/* format of the encoded value */
+#define DW_EH_PE_APPL_MASK	0x70	/* how the value is to be applied */
+
+/* Pointer-encoding formats: */
+#define DW_EH_PE_omit		0xff
+#define DW_EH_PE_ptr		0x00	/* pointer-sized unsigned value */
+#define DW_EH_PE_udata4		0x03	/* unsigned 32-bit value */
+#define DW_EH_PE_udata8		0x04	/* unsigned 64-bit value */
+#define DW_EH_PE_sdata4		0x0b	/* signed 32-bit value */
+#define DW_EH_PE_sdata8		0x0c	/* signed 64-bit value */
+
+/* Pointer-encoding application: */
+#define DW_EH_PE_absptr		0x00	/* absolute value */
+#define DW_EH_PE_pcrel		0x10	/* rel. to addr. of encoded value */
+
+/*
+ * The following are not documented by LSB v1.3, yet they are used by
+ * GCC, presumably they aren't documented by LSB since they aren't
+ * used on Linux:
+ */
+#define DW_EH_PE_funcrel	0x40	/* start-of-procedure-relative */
+#define DW_EH_PE_aligned	0x50	/* aligned pointer */
+
+/* Flags intentionaly not handled, since they're not needed:
+ * #define DW_EH_PE_indirect      0x80
+ * #define DW_EH_PE_uleb128       0x01
+ * #define DW_EH_PE_udata2        0x02
+ * #define DW_EH_PE_sleb128       0x09
+ * #define DW_EH_PE_sdata2        0x0a
+ * #define DW_EH_PE_textrel       0x20
+ * #define DW_EH_PE_datarel       0x30
+ */
+
+struct unwind_info {
+	struct perf_sample	*sample;
+	struct machine		*machine;
+	struct thread		*thread;
+};
+
+#define dw_read(ptr, type, end) ({	\
+	type *__p = (type *) ptr;	\
+	type  __v;			\
+	if ((__p + 1) > (type *) end)	\
+		return -EINVAL;		\
+	__v = *__p++;			\
+	ptr = (typeof(ptr)) __p;	\
+	__v;				\
+	})
+
+static int __dw_read_encoded_value(u8 **p, u8 *end, u64 *val,
+				   u8 encoding)
+{
+	u8 *cur = *p;
+	*val = 0;
+
+	switch (encoding) {
+	case DW_EH_PE_omit:
+		*val = 0;
+		goto out;
+	case DW_EH_PE_ptr:
+		*val = dw_read(cur, unsigned long, end);
+		goto out;
+	default:
+		break;
+	}
+
+	switch (encoding & DW_EH_PE_APPL_MASK) {
+	case DW_EH_PE_absptr:
+		break;
+	case DW_EH_PE_pcrel:
+		*val = (unsigned long) cur;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if ((encoding & 0x07) == 0x00)
+		encoding |= DW_EH_PE_udata4;
+
+	switch (encoding & DW_EH_PE_FORMAT_MASK) {
+	case DW_EH_PE_sdata4:
+		*val += dw_read(cur, s32, end);
+		break;
+	case DW_EH_PE_udata4:
+		*val += dw_read(cur, u32, end);
+		break;
+	case DW_EH_PE_sdata8:
+		*val += dw_read(cur, s64, end);
+		break;
+	case DW_EH_PE_udata8:
+		*val += dw_read(cur, u64, end);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+ out:
+	*p = cur;
+	return 0;
+}
+
+#define dw_read_encoded_value(ptr, end, enc) ({			\
+	u64 __v;						\
+	if (__dw_read_encoded_value(&ptr, end, &__v, enc)) {	\
+		return -EINVAL;                                 \
+	}                                                       \
+	__v;                                                    \
+	})
+
+static Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
+				    GElf_Shdr *shp, const char *name)
+{
+	Elf_Scn *sec = NULL;
+
+	while ((sec = elf_nextscn(elf, sec)) != NULL) {
+		char *str;
+
+		gelf_getshdr(sec, shp);
+		str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
+		if (!strcmp(name, str))
+			break;
+	}
+
+	return sec;
+}
+
+static u64 elf_section_offset(int fd, const char *name)
+{
+	Elf *elf;
+	GElf_Ehdr ehdr;
+	GElf_Shdr shdr;
+	u64 offset = 0;
+
+	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
+	if (elf == NULL)
+		return 0;
+
+	do {
+		if (gelf_getehdr(elf, &ehdr) == NULL)
+			break;
+
+		if (!elf_section_by_name(elf, &ehdr, &shdr, name))
+			break;
+
+		offset = shdr.sh_offset;
+	} while (0);
+
+	elf_end(elf);
+	return offset;
+}
+
+struct table_entry {
+	u32 start_ip_offset;
+	u32 fde_offset;
+};
+
+struct eh_frame_hdr {
+	unsigned char version;
+	unsigned char eh_frame_ptr_enc;
+	unsigned char fde_count_enc;
+	unsigned char table_enc;
+
+	/*
+	 * The rest of the header is variable-length and consists of the
+	 * following members:
+	 *
+	 *	encoded_t eh_frame_ptr;
+	 *	encoded_t fde_count;
+	 */
+
+	/* A single encoded pointer should not be more than 8 bytes. */
+	u64 enc[2];
+
+	/*
+	 * struct {
+	 *    encoded_t start_ip;
+	 *    encoded_t fde_addr;
+	 * } binary_search_table[fde_count];
+	 */
+	char data[0];
+} __packed;
+
+static int unwind_spec_ehframe(struct dso *dso, struct machine *machine,
+			       u64 offset, u64 *table_data, u64 *segbase,
+			       u64 *fde_count)
+{
+	struct eh_frame_hdr hdr;
+	u8 *enc = (u8 *) &hdr.enc;
+	u8 *end = (u8 *) &hdr.data;
+	ssize_t r;
+
+	r = dso__data_read_offset(dso, machine, offset,
+				  (u8 *) &hdr, sizeof(hdr));
+	if (r != sizeof(hdr))
+		return -EINVAL;
+
+	/* We dont need eh_frame_ptr, just skip it. */
+	dw_read_encoded_value(enc, end, hdr.eh_frame_ptr_enc);
+
+	*fde_count  = dw_read_encoded_value(enc, end, hdr.fde_count_enc);
+	*segbase    = offset;
+	*table_data = (enc - (u8 *) &hdr) + offset;
+	return 0;
+}
+
+static int read_unwind_spec_eh_frame(struct dso *dso, struct machine *machine,
+				     u64 *table_data, u64 *segbase,
+				     u64 *fde_count)
+{
+	int ret = -EINVAL, fd;
+	u64 offset;
+
+	fd = dso__data_fd(dso, machine);
+	if (fd < 0)
+		return -EINVAL;
+
+	/* Check the .eh_frame section for unwinding info */
+	offset = elf_section_offset(fd, ".eh_frame_hdr");
+	close(fd);
+
+	if (offset)
+		ret = unwind_spec_ehframe(dso, machine, offset,
+					  table_data, segbase,
+					  fde_count);
+
+	return ret;
+}
+
+#ifndef NO_LIBUNWIND_DEBUG_FRAME
+static int read_unwind_spec_debug_frame(struct dso *dso,
+					struct machine *machine, u64 *offset)
+{
+	int fd = dso__data_fd(dso, machine);
+
+	if (fd < 0)
+		return -EINVAL;
+
+	/* Check the .debug_frame section for unwinding info */
+	*offset = elf_section_offset(fd, ".debug_frame");
+	close(fd);
+
+	if (*offset)
+		return 0;
+
+	return -EINVAL;
+}
+#endif
+
+static struct map *find_map(unw_word_t ip, struct unwind_info *ui)
+{
+	struct addr_location al;
+
+	thread__find_addr_map(ui->thread, ui->machine, PERF_RECORD_MISC_USER,
+			      MAP__FUNCTION, ip, &al);
+	return al.map;
+}
+
+static int
+find_proc_info(unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi,
+	       int need_unwind_info, void *arg)
+{
+	struct unwind_info *ui = arg;
+	struct map *map;
+	unw_dyn_info_t di;
+	u64 table_data, segbase, fde_count;
+
+	map = find_map(ip, ui);
+	if (!map || !map->dso)
+		return -EINVAL;
+
+	pr_debug("unwind: find_proc_info dso %s\n", map->dso->name);
+
+	/* Check the .eh_frame section for unwinding info */
+	if (!read_unwind_spec_eh_frame(map->dso, ui->machine,
+				       &table_data, &segbase, &fde_count)) {
+		memset(&di, 0, sizeof(di));
+		di.format   = UNW_INFO_FORMAT_REMOTE_TABLE;
+		di.start_ip = map->start;
+		di.end_ip   = map->end;
+		di.u.rti.segbase    = map->start + segbase;
+		di.u.rti.table_data = map->start + table_data;
+		di.u.rti.table_len  = fde_count * sizeof(struct table_entry)
+				      / sizeof(unw_word_t);
+		return dwarf_search_unwind_table(as, ip, &di, pi,
+						 need_unwind_info, arg);
+	}
+
+#ifndef NO_LIBUNWIND_DEBUG_FRAME
+	/* Check the .debug_frame section for unwinding info */
+	if (!read_unwind_spec_debug_frame(map->dso, ui->machine, &segbase)) {
+		memset(&di, 0, sizeof(di));
+		dwarf_find_debug_frame(0, &di, ip, 0, map->dso->name,
+				       map->start, map->end);
+		return dwarf_search_unwind_table(as, ip, &di, pi,
+						 need_unwind_info, arg);
+	}
+#endif
+
+	return -EINVAL;
+}
+
+static int access_fpreg(unw_addr_space_t __maybe_unused as,
+			unw_regnum_t __maybe_unused num,
+			unw_fpreg_t __maybe_unused *val,
+			int __maybe_unused __write,
+			void __maybe_unused *arg)
+{
+	pr_err("unwind: access_fpreg unsupported\n");
+	return -UNW_EINVAL;
+}
+
+static int get_dyn_info_list_addr(unw_addr_space_t __maybe_unused as,
+				  unw_word_t __maybe_unused *dil_addr,
+				  void __maybe_unused *arg)
+{
+	return -UNW_ENOINFO;
+}
+
+static int resume(unw_addr_space_t __maybe_unused as,
+		  unw_cursor_t __maybe_unused *cu,
+		  void __maybe_unused *arg)
+{
+	pr_err("unwind: resume unsupported\n");
+	return -UNW_EINVAL;
+}
+
+static int
+get_proc_name(unw_addr_space_t __maybe_unused as,
+	      unw_word_t __maybe_unused addr,
+		char __maybe_unused *bufp, size_t __maybe_unused buf_len,
+		unw_word_t __maybe_unused *offp, void __maybe_unused *arg)
+{
+	pr_err("unwind: get_proc_name unsupported\n");
+	return -UNW_EINVAL;
+}
+
+static int access_dso_mem(struct unwind_info *ui, unw_word_t addr,
+			  unw_word_t *data)
+{
+	struct addr_location al;
+	ssize_t size;
+
+	thread__find_addr_map(ui->thread, ui->machine, PERF_RECORD_MISC_USER,
+			      MAP__FUNCTION, addr, &al);
+	if (!al.map) {
+		pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
+		return -1;
+	}
+
+	if (!al.map->dso)
+		return -1;
+
+	size = dso__data_read_addr(al.map->dso, al.map, ui->machine,
+				   addr, (u8 *) data, sizeof(*data));
+
+	return !(size == sizeof(*data));
+}
+
+static int reg_value(unw_word_t *valp, struct regs_dump *regs, int id)
+{
+	int i, idx = 0;
+	u64 mask = regs->mask;
+
+	if (!(mask & (1 << id)))
+		return -EINVAL;
+
+	for (i = 0; i < id; i++) {
+		if (mask & (1 << i))
+			idx++;
+	}
+
+	*valp = regs->regs[idx];
+	return 0;
+}
+
+static int access_mem(unw_addr_space_t __maybe_unused as,
+		      unw_word_t addr, unw_word_t *valp,
+		      int __write, void *arg)
+{
+	struct unwind_info *ui = arg;
+	struct stack_dump *stack = &ui->sample->user_stack;
+	unw_word_t start, end;
+	int offset;
+	int ret;
+
+	/* Don't support write, probably not needed. */
+	if (__write || !stack || !ui->sample->user_regs.regs) {
+		*valp = 0;
+		return 0;
+	}
+
+	ret = reg_value(&start, &ui->sample->user_regs, PERF_REG_SP);
+	if (ret)
+		return ret;
+
+	end = start + stack->size;
+
+	/* Check overflow. */
+	if (addr + sizeof(unw_word_t) < addr)
+		return -EINVAL;
+
+	if (addr < start || addr + sizeof(unw_word_t) >= end) {
+		ret = access_dso_mem(ui, addr, valp);
+		if (ret) {
+			pr_debug("unwind: access_mem %p not inside range %p-%p\n",
+				(void *)addr, (void *)start, (void *)end);
+			*valp = 0;
+			return ret;
+		}
+		return 0;
+	}
+
+	offset = addr - start;
+	*valp  = *(unw_word_t *)&stack->data[offset];
+	pr_debug("unwind: access_mem addr %p, val %lx, offset %d\n",
+		 (void *)addr, (unsigned long)*valp, offset);
+	return 0;
+}
+
+static int access_reg(unw_addr_space_t __maybe_unused as,
+		      unw_regnum_t regnum, unw_word_t *valp,
+		      int __write, void *arg)
+{
+	struct unwind_info *ui = arg;
+	int id, ret;
+
+	/* Don't support write, I suspect we don't need it. */
+	if (__write) {
+		pr_err("unwind: access_reg w %d\n", regnum);
+		return 0;
+	}
+
+	if (!ui->sample->user_regs.regs) {
+		*valp = 0;
+		return 0;
+	}
+
+	id = unwind__arch_reg_id(regnum);
+	if (id < 0)
+		return -EINVAL;
+
+	ret = reg_value(valp, &ui->sample->user_regs, id);
+	if (ret) {
+		pr_err("unwind: can't read reg %d\n", regnum);
+		return ret;
+	}
+
+	pr_debug("unwind: reg %d, val %lx\n", regnum, (unsigned long)*valp);
+	return 0;
+}
+
+static void put_unwind_info(unw_addr_space_t __maybe_unused as,
+			    unw_proc_info_t *pi __maybe_unused,
+			    void *arg __maybe_unused)
+{
+	pr_debug("unwind: put_unwind_info called\n");
+}
+
+static int entry(u64 ip, struct thread *thread, struct machine *machine,
+		 unwind_entry_cb_t cb, void *arg)
+{
+	struct unwind_entry e;
+	struct addr_location al;
+
+	thread__find_addr_location(thread, machine,
+				   PERF_RECORD_MISC_USER,
+				   MAP__FUNCTION, ip, &al);
+
+	e.ip = ip;
+	e.map = al.map;
+	e.sym = al.sym;
+
+	pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
+		 al.sym ? al.sym->name : "''",
+		 ip,
+		 al.map ? al.map->map_ip(al.map, ip) : (u64) 0);
+
+	return cb(&e, arg);
+}
+
+static void display_error(int err)
+{
+	switch (err) {
+	case UNW_EINVAL:
+		pr_err("unwind: Only supports local.\n");
+		break;
+	case UNW_EUNSPEC:
+		pr_err("unwind: Unspecified error.\n");
+		break;
+	case UNW_EBADREG:
+		pr_err("unwind: Register unavailable.\n");
+		break;
+	default:
+		break;
+	}
+}
+
+static unw_accessors_t accessors = {
+	.find_proc_info		= find_proc_info,
+	.put_unwind_info	= put_unwind_info,
+	.get_dyn_info_list_addr	= get_dyn_info_list_addr,
+	.access_mem		= access_mem,
+	.access_reg		= access_reg,
+	.access_fpreg		= access_fpreg,
+	.resume			= resume,
+	.get_proc_name		= get_proc_name,
+};
+
+static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
+		       void *arg, int max_stack)
+{
+	unw_addr_space_t addr_space;
+	unw_cursor_t c;
+	int ret;
+
+	addr_space = unw_create_addr_space(&accessors, 0);
+	if (!addr_space) {
+		pr_err("unwind: Can't create unwind address space.\n");
+		return -ENOMEM;
+	}
+
+	ret = unw_init_remote(&c, addr_space, ui);
+	if (ret)
+		display_error(ret);
+
+	while (!ret && (unw_step(&c) > 0) && max_stack--) {
+		unw_word_t ip;
+
+		unw_get_reg(&c, UNW_REG_IP, &ip);
+		ret = ip ? entry(ip, ui->thread, ui->machine, cb, arg) : 0;
+	}
+
+	unw_destroy_addr_space(addr_space);
+	return ret;
+}
+
+int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
+			struct machine *machine, struct thread *thread,
+			struct perf_sample *data, int max_stack)
+{
+	unw_word_t ip;
+	struct unwind_info ui = {
+		.sample       = data,
+		.thread       = thread,
+		.machine      = machine,
+	};
+	int ret;
+
+	if (!data->user_regs.regs)
+		return -EINVAL;
+
+	ret = reg_value(&ip, &data->user_regs, PERF_REG_IP);
+	if (ret)
+		return ret;
+
+	ret = entry(ip, thread, machine, cb, arg);
+	if (ret)
+		return -ENOMEM;
+
+	return --max_stack > 0 ? get_entries(&ui, cb, arg, max_stack) : 0;
+}
diff --git a/tools/perf/util/unwind.c b/tools/perf/util/unwind.c
deleted file mode 100644
index 226586e..0000000
--- a/tools/perf/util/unwind.c
+++ /dev/null
@@ -1,611 +0,0 @@
-/*
- * Post mortem Dwarf CFI based unwinding on top of regs and stack dumps.
- *
- * Lots of this code have been borrowed or heavily inspired from parts of
- * the libunwind 0.99 code which are (amongst other contributors I may have
- * forgotten):
- *
- * Copyright (C) 2002-2007 Hewlett-Packard Co
- *	Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
- *
- * And the bugs have been added by:
- *
- * Copyright (C) 2010, Frederic Weisbecker <fweisbec@gmail.com>
- * Copyright (C) 2012, Jiri Olsa <jolsa@redhat.com>
- *
- */
-
-#include <elf.h>
-#include <gelf.h>
-#include <fcntl.h>
-#include <string.h>
-#include <unistd.h>
-#include <sys/mman.h>
-#include <linux/list.h>
-#include <libunwind.h>
-#include <libunwind-ptrace.h>
-#include "thread.h"
-#include "session.h"
-#include "perf_regs.h"
-#include "unwind.h"
-#include "util.h"
-
-extern int
-UNW_OBJ(dwarf_search_unwind_table) (unw_addr_space_t as,
-				    unw_word_t ip,
-				    unw_dyn_info_t *di,
-				    unw_proc_info_t *pi,
-				    int need_unwind_info, void *arg);
-
-#define dwarf_search_unwind_table UNW_OBJ(dwarf_search_unwind_table)
-
-extern int
-UNW_OBJ(dwarf_find_debug_frame) (int found, unw_dyn_info_t *di_debug,
-				 unw_word_t ip,
-				 unw_word_t segbase,
-				 const char *obj_name, unw_word_t start,
-				 unw_word_t end);
-
-#define dwarf_find_debug_frame UNW_OBJ(dwarf_find_debug_frame)
-
-#define DW_EH_PE_FORMAT_MASK	0x0f	/* format of the encoded value */
-#define DW_EH_PE_APPL_MASK	0x70	/* how the value is to be applied */
-
-/* Pointer-encoding formats: */
-#define DW_EH_PE_omit		0xff
-#define DW_EH_PE_ptr		0x00	/* pointer-sized unsigned value */
-#define DW_EH_PE_udata4		0x03	/* unsigned 32-bit value */
-#define DW_EH_PE_udata8		0x04	/* unsigned 64-bit value */
-#define DW_EH_PE_sdata4		0x0b	/* signed 32-bit value */
-#define DW_EH_PE_sdata8		0x0c	/* signed 64-bit value */
-
-/* Pointer-encoding application: */
-#define DW_EH_PE_absptr		0x00	/* absolute value */
-#define DW_EH_PE_pcrel		0x10	/* rel. to addr. of encoded value */
-
-/*
- * The following are not documented by LSB v1.3, yet they are used by
- * GCC, presumably they aren't documented by LSB since they aren't
- * used on Linux:
- */
-#define DW_EH_PE_funcrel	0x40	/* start-of-procedure-relative */
-#define DW_EH_PE_aligned	0x50	/* aligned pointer */
-
-/* Flags intentionaly not handled, since they're not needed:
- * #define DW_EH_PE_indirect      0x80
- * #define DW_EH_PE_uleb128       0x01
- * #define DW_EH_PE_udata2        0x02
- * #define DW_EH_PE_sleb128       0x09
- * #define DW_EH_PE_sdata2        0x0a
- * #define DW_EH_PE_textrel       0x20
- * #define DW_EH_PE_datarel       0x30
- */
-
-struct unwind_info {
-	struct perf_sample	*sample;
-	struct machine		*machine;
-	struct thread		*thread;
-};
-
-#define dw_read(ptr, type, end) ({	\
-	type *__p = (type *) ptr;	\
-	type  __v;			\
-	if ((__p + 1) > (type *) end)	\
-		return -EINVAL;		\
-	__v = *__p++;			\
-	ptr = (typeof(ptr)) __p;	\
-	__v;				\
-	})
-
-static int __dw_read_encoded_value(u8 **p, u8 *end, u64 *val,
-				   u8 encoding)
-{
-	u8 *cur = *p;
-	*val = 0;
-
-	switch (encoding) {
-	case DW_EH_PE_omit:
-		*val = 0;
-		goto out;
-	case DW_EH_PE_ptr:
-		*val = dw_read(cur, unsigned long, end);
-		goto out;
-	default:
-		break;
-	}
-
-	switch (encoding & DW_EH_PE_APPL_MASK) {
-	case DW_EH_PE_absptr:
-		break;
-	case DW_EH_PE_pcrel:
-		*val = (unsigned long) cur;
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	if ((encoding & 0x07) == 0x00)
-		encoding |= DW_EH_PE_udata4;
-
-	switch (encoding & DW_EH_PE_FORMAT_MASK) {
-	case DW_EH_PE_sdata4:
-		*val += dw_read(cur, s32, end);
-		break;
-	case DW_EH_PE_udata4:
-		*val += dw_read(cur, u32, end);
-		break;
-	case DW_EH_PE_sdata8:
-		*val += dw_read(cur, s64, end);
-		break;
-	case DW_EH_PE_udata8:
-		*val += dw_read(cur, u64, end);
-		break;
-	default:
-		return -EINVAL;
-	}
-
- out:
-	*p = cur;
-	return 0;
-}
-
-#define dw_read_encoded_value(ptr, end, enc) ({			\
-	u64 __v;						\
-	if (__dw_read_encoded_value(&ptr, end, &__v, enc)) {	\
-		return -EINVAL;                                 \
-	}                                                       \
-	__v;                                                    \
-	})
-
-static Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
-				    GElf_Shdr *shp, const char *name)
-{
-	Elf_Scn *sec = NULL;
-
-	while ((sec = elf_nextscn(elf, sec)) != NULL) {
-		char *str;
-
-		gelf_getshdr(sec, shp);
-		str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
-		if (!strcmp(name, str))
-			break;
-	}
-
-	return sec;
-}
-
-static u64 elf_section_offset(int fd, const char *name)
-{
-	Elf *elf;
-	GElf_Ehdr ehdr;
-	GElf_Shdr shdr;
-	u64 offset = 0;
-
-	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
-	if (elf == NULL)
-		return 0;
-
-	do {
-		if (gelf_getehdr(elf, &ehdr) == NULL)
-			break;
-
-		if (!elf_section_by_name(elf, &ehdr, &shdr, name))
-			break;
-
-		offset = shdr.sh_offset;
-	} while (0);
-
-	elf_end(elf);
-	return offset;
-}
-
-struct table_entry {
-	u32 start_ip_offset;
-	u32 fde_offset;
-};
-
-struct eh_frame_hdr {
-	unsigned char version;
-	unsigned char eh_frame_ptr_enc;
-	unsigned char fde_count_enc;
-	unsigned char table_enc;
-
-	/*
-	 * The rest of the header is variable-length and consists of the
-	 * following members:
-	 *
-	 *	encoded_t eh_frame_ptr;
-	 *	encoded_t fde_count;
-	 */
-
-	/* A single encoded pointer should not be more than 8 bytes. */
-	u64 enc[2];
-
-	/*
-	 * struct {
-	 *    encoded_t start_ip;
-	 *    encoded_t fde_addr;
-	 * } binary_search_table[fde_count];
-	 */
-	char data[0];
-} __packed;
-
-static int unwind_spec_ehframe(struct dso *dso, struct machine *machine,
-			       u64 offset, u64 *table_data, u64 *segbase,
-			       u64 *fde_count)
-{
-	struct eh_frame_hdr hdr;
-	u8 *enc = (u8 *) &hdr.enc;
-	u8 *end = (u8 *) &hdr.data;
-	ssize_t r;
-
-	r = dso__data_read_offset(dso, machine, offset,
-				  (u8 *) &hdr, sizeof(hdr));
-	if (r != sizeof(hdr))
-		return -EINVAL;
-
-	/* We dont need eh_frame_ptr, just skip it. */
-	dw_read_encoded_value(enc, end, hdr.eh_frame_ptr_enc);
-
-	*fde_count  = dw_read_encoded_value(enc, end, hdr.fde_count_enc);
-	*segbase    = offset;
-	*table_data = (enc - (u8 *) &hdr) + offset;
-	return 0;
-}
-
-static int read_unwind_spec_eh_frame(struct dso *dso, struct machine *machine,
-				     u64 *table_data, u64 *segbase,
-				     u64 *fde_count)
-{
-	int ret = -EINVAL, fd;
-	u64 offset;
-
-	fd = dso__data_fd(dso, machine);
-	if (fd < 0)
-		return -EINVAL;
-
-	/* Check the .eh_frame section for unwinding info */
-	offset = elf_section_offset(fd, ".eh_frame_hdr");
-	close(fd);
-
-	if (offset)
-		ret = unwind_spec_ehframe(dso, machine, offset,
-					  table_data, segbase,
-					  fde_count);
-
-	return ret;
-}
-
-#ifndef NO_LIBUNWIND_DEBUG_FRAME
-static int read_unwind_spec_debug_frame(struct dso *dso,
-					struct machine *machine, u64 *offset)
-{
-	int fd = dso__data_fd(dso, machine);
-
-	if (fd < 0)
-		return -EINVAL;
-
-	/* Check the .debug_frame section for unwinding info */
-	*offset = elf_section_offset(fd, ".debug_frame");
-	close(fd);
-
-	if (*offset)
-		return 0;
-
-	return -EINVAL;
-}
-#endif
-
-static struct map *find_map(unw_word_t ip, struct unwind_info *ui)
-{
-	struct addr_location al;
-
-	thread__find_addr_map(ui->thread, ui->machine, PERF_RECORD_MISC_USER,
-			      MAP__FUNCTION, ip, &al);
-	return al.map;
-}
-
-static int
-find_proc_info(unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi,
-	       int need_unwind_info, void *arg)
-{
-	struct unwind_info *ui = arg;
-	struct map *map;
-	unw_dyn_info_t di;
-	u64 table_data, segbase, fde_count;
-
-	map = find_map(ip, ui);
-	if (!map || !map->dso)
-		return -EINVAL;
-
-	pr_debug("unwind: find_proc_info dso %s\n", map->dso->name);
-
-	/* Check the .eh_frame section for unwinding info */
-	if (!read_unwind_spec_eh_frame(map->dso, ui->machine,
-				       &table_data, &segbase, &fde_count)) {
-		memset(&di, 0, sizeof(di));
-		di.format   = UNW_INFO_FORMAT_REMOTE_TABLE;
-		di.start_ip = map->start;
-		di.end_ip   = map->end;
-		di.u.rti.segbase    = map->start + segbase;
-		di.u.rti.table_data = map->start + table_data;
-		di.u.rti.table_len  = fde_count * sizeof(struct table_entry)
-				      / sizeof(unw_word_t);
-		return dwarf_search_unwind_table(as, ip, &di, pi,
-						 need_unwind_info, arg);
-	}
-
-#ifndef NO_LIBUNWIND_DEBUG_FRAME
-	/* Check the .debug_frame section for unwinding info */
-	if (!read_unwind_spec_debug_frame(map->dso, ui->machine, &segbase)) {
-		memset(&di, 0, sizeof(di));
-		dwarf_find_debug_frame(0, &di, ip, 0, map->dso->name,
-				       map->start, map->end);
-		return dwarf_search_unwind_table(as, ip, &di, pi,
-						 need_unwind_info, arg);
-	}
-#endif
-
-	return -EINVAL;
-}
-
-static int access_fpreg(unw_addr_space_t __maybe_unused as,
-			unw_regnum_t __maybe_unused num,
-			unw_fpreg_t __maybe_unused *val,
-			int __maybe_unused __write,
-			void __maybe_unused *arg)
-{
-	pr_err("unwind: access_fpreg unsupported\n");
-	return -UNW_EINVAL;
-}
-
-static int get_dyn_info_list_addr(unw_addr_space_t __maybe_unused as,
-				  unw_word_t __maybe_unused *dil_addr,
-				  void __maybe_unused *arg)
-{
-	return -UNW_ENOINFO;
-}
-
-static int resume(unw_addr_space_t __maybe_unused as,
-		  unw_cursor_t __maybe_unused *cu,
-		  void __maybe_unused *arg)
-{
-	pr_err("unwind: resume unsupported\n");
-	return -UNW_EINVAL;
-}
-
-static int
-get_proc_name(unw_addr_space_t __maybe_unused as,
-	      unw_word_t __maybe_unused addr,
-		char __maybe_unused *bufp, size_t __maybe_unused buf_len,
-		unw_word_t __maybe_unused *offp, void __maybe_unused *arg)
-{
-	pr_err("unwind: get_proc_name unsupported\n");
-	return -UNW_EINVAL;
-}
-
-static int access_dso_mem(struct unwind_info *ui, unw_word_t addr,
-			  unw_word_t *data)
-{
-	struct addr_location al;
-	ssize_t size;
-
-	thread__find_addr_map(ui->thread, ui->machine, PERF_RECORD_MISC_USER,
-			      MAP__FUNCTION, addr, &al);
-	if (!al.map) {
-		pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
-		return -1;
-	}
-
-	if (!al.map->dso)
-		return -1;
-
-	size = dso__data_read_addr(al.map->dso, al.map, ui->machine,
-				   addr, (u8 *) data, sizeof(*data));
-
-	return !(size == sizeof(*data));
-}
-
-static int reg_value(unw_word_t *valp, struct regs_dump *regs, int id)
-{
-	int i, idx = 0;
-	u64 mask = regs->mask;
-
-	if (!(mask & (1 << id)))
-		return -EINVAL;
-
-	for (i = 0; i < id; i++) {
-		if (mask & (1 << i))
-			idx++;
-	}
-
-	*valp = regs->regs[idx];
-	return 0;
-}
-
-static int access_mem(unw_addr_space_t __maybe_unused as,
-		      unw_word_t addr, unw_word_t *valp,
-		      int __write, void *arg)
-{
-	struct unwind_info *ui = arg;
-	struct stack_dump *stack = &ui->sample->user_stack;
-	unw_word_t start, end;
-	int offset;
-	int ret;
-
-	/* Don't support write, probably not needed. */
-	if (__write || !stack || !ui->sample->user_regs.regs) {
-		*valp = 0;
-		return 0;
-	}
-
-	ret = reg_value(&start, &ui->sample->user_regs, PERF_REG_SP);
-	if (ret)
-		return ret;
-
-	end = start + stack->size;
-
-	/* Check overflow. */
-	if (addr + sizeof(unw_word_t) < addr)
-		return -EINVAL;
-
-	if (addr < start || addr + sizeof(unw_word_t) >= end) {
-		ret = access_dso_mem(ui, addr, valp);
-		if (ret) {
-			pr_debug("unwind: access_mem %p not inside range %p-%p\n",
-				(void *)addr, (void *)start, (void *)end);
-			*valp = 0;
-			return ret;
-		}
-		return 0;
-	}
-
-	offset = addr - start;
-	*valp  = *(unw_word_t *)&stack->data[offset];
-	pr_debug("unwind: access_mem addr %p, val %lx, offset %d\n",
-		 (void *)addr, (unsigned long)*valp, offset);
-	return 0;
-}
-
-static int access_reg(unw_addr_space_t __maybe_unused as,
-		      unw_regnum_t regnum, unw_word_t *valp,
-		      int __write, void *arg)
-{
-	struct unwind_info *ui = arg;
-	int id, ret;
-
-	/* Don't support write, I suspect we don't need it. */
-	if (__write) {
-		pr_err("unwind: access_reg w %d\n", regnum);
-		return 0;
-	}
-
-	if (!ui->sample->user_regs.regs) {
-		*valp = 0;
-		return 0;
-	}
-
-	id = unwind__arch_reg_id(regnum);
-	if (id < 0)
-		return -EINVAL;
-
-	ret = reg_value(valp, &ui->sample->user_regs, id);
-	if (ret) {
-		pr_err("unwind: can't read reg %d\n", regnum);
-		return ret;
-	}
-
-	pr_debug("unwind: reg %d, val %lx\n", regnum, (unsigned long)*valp);
-	return 0;
-}
-
-static void put_unwind_info(unw_addr_space_t __maybe_unused as,
-			    unw_proc_info_t *pi __maybe_unused,
-			    void *arg __maybe_unused)
-{
-	pr_debug("unwind: put_unwind_info called\n");
-}
-
-static int entry(u64 ip, struct thread *thread, struct machine *machine,
-		 unwind_entry_cb_t cb, void *arg)
-{
-	struct unwind_entry e;
-	struct addr_location al;
-
-	thread__find_addr_location(thread, machine,
-				   PERF_RECORD_MISC_USER,
-				   MAP__FUNCTION, ip, &al);
-
-	e.ip = ip;
-	e.map = al.map;
-	e.sym = al.sym;
-
-	pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
-		 al.sym ? al.sym->name : "''",
-		 ip,
-		 al.map ? al.map->map_ip(al.map, ip) : (u64) 0);
-
-	return cb(&e, arg);
-}
-
-static void display_error(int err)
-{
-	switch (err) {
-	case UNW_EINVAL:
-		pr_err("unwind: Only supports local.\n");
-		break;
-	case UNW_EUNSPEC:
-		pr_err("unwind: Unspecified error.\n");
-		break;
-	case UNW_EBADREG:
-		pr_err("unwind: Register unavailable.\n");
-		break;
-	default:
-		break;
-	}
-}
-
-static unw_accessors_t accessors = {
-	.find_proc_info		= find_proc_info,
-	.put_unwind_info	= put_unwind_info,
-	.get_dyn_info_list_addr	= get_dyn_info_list_addr,
-	.access_mem		= access_mem,
-	.access_reg		= access_reg,
-	.access_fpreg		= access_fpreg,
-	.resume			= resume,
-	.get_proc_name		= get_proc_name,
-};
-
-static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
-		       void *arg, int max_stack)
-{
-	unw_addr_space_t addr_space;
-	unw_cursor_t c;
-	int ret;
-
-	addr_space = unw_create_addr_space(&accessors, 0);
-	if (!addr_space) {
-		pr_err("unwind: Can't create unwind address space.\n");
-		return -ENOMEM;
-	}
-
-	ret = unw_init_remote(&c, addr_space, ui);
-	if (ret)
-		display_error(ret);
-
-	while (!ret && (unw_step(&c) > 0) && max_stack--) {
-		unw_word_t ip;
-
-		unw_get_reg(&c, UNW_REG_IP, &ip);
-		ret = ip ? entry(ip, ui->thread, ui->machine, cb, arg) : 0;
-	}
-
-	unw_destroy_addr_space(addr_space);
-	return ret;
-}
-
-int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
-			struct machine *machine, struct thread *thread,
-			struct perf_sample *data, int max_stack)
-{
-	unw_word_t ip;
-	struct unwind_info ui = {
-		.sample       = data,
-		.thread       = thread,
-		.machine      = machine,
-	};
-	int ret;
-
-	if (!data->user_regs.regs)
-		return -EINVAL;
-
-	ret = reg_value(&ip, &data->user_regs, PERF_REG_IP);
-	if (ret)
-		return ret;
-
-	ret = entry(ip, thread, machine, cb, arg);
-	if (ret)
-		return -ENOMEM;
-
-	return --max_stack > 0 ? get_entries(&ui, cb, arg, max_stack) : 0;
-}
-- 
1.8.3.1