1 files changed, 0 insertions, 831 deletions

diff --git a/tools/perf/util/unwind-libunwind-local.c b/tools/perf/util/unwind-libunwind-local.c
deleted file mode 100644
index 16c2b03831f3..000000000000
--- a/tools/perf/util/unwind-libunwind-local.c
+++ /dev/null
@@ -1,831 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * 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 <errno.h>
-#include <gelf.h>
-#include <fcntl.h>
-#include <inttypes.h>
-#include <string.h>
-#include <unistd.h>
-#include <sys/mman.h>
-#include <linux/list.h>
-#include <linux/zalloc.h>
-#ifndef REMOTE_UNWIND_LIBUNWIND
-#include <libunwind.h>
-#include <libunwind-ptrace.h>
-#endif
-#include "callchain.h"
-#include "thread.h"
-#include "session.h"
-#include "perf_regs.h"
-#include "unwind.h"
-#include "map.h"
-#include "symbol.h"
-#include "debug.h"
-#include "asm/bug.h"
-#include "dso.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 intentionally 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;
-	bool			 best_effort;
-};
-
-#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 int elf_section_address_and_offset(int fd, const char *name, u64 *address, u64 *offset)
-{
-	Elf *elf;
-	GElf_Ehdr ehdr;
-	GElf_Shdr shdr;
-	int ret = -1;
-
-	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
-	if (elf == NULL)
-		return -1;
-
-	if (gelf_getehdr(elf, &ehdr) == NULL)
-		goto out_err;
-
-	if (!elf_section_by_name(elf, &ehdr, &shdr, name, NULL))
-		goto out_err;
-
-	*address = shdr.sh_addr;
-	*offset = shdr.sh_offset;
-	ret = 0;
-out_err:
-	elf_end(elf);
-	return ret;
-}
-
-#ifndef NO_LIBUNWIND_DEBUG_FRAME
-static u64 elf_section_offset(int fd, const char *name)
-{
-	u64 address, offset = 0;
-
-	if (elf_section_address_and_offset(fd, name, &address, &offset))
-		return 0;
-
-	return offset;
-}
-#endif
-
-static u64 elf_base_address(int fd)
-{
-	Elf *elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
-	GElf_Phdr phdr;
-	u64 retval = 0;
-	size_t i, phdrnum = 0;
-
-	if (elf == NULL)
-		return 0;
-	(void)elf_getphdrnum(elf, &phdrnum);
-	/* PT_LOAD segments are sorted by p_vaddr, so the first has the minimum p_vaddr. */
-	for (i = 0; i < phdrnum; i++) {
-		if (gelf_getphdr(elf, i, &phdr) && phdr.p_type == PT_LOAD) {
-			retval = phdr.p_vaddr & -getpagesize();
-			break;
-		}
-	}
-
-	elf_end(elf);
-	return retval;
-}
-
-#ifndef NO_LIBUNWIND_DEBUG_FRAME
-static int elf_is_exec(int fd, const char *name)
-{
-	Elf *elf;
-	GElf_Ehdr ehdr;
-	int retval = 0;
-
-	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
-	if (elf == NULL)
-		return 0;
-	if (gelf_getehdr(elf, &ehdr) == NULL)
-		goto out;
-
-	retval = (ehdr.e_type == ET_EXEC);
-
-out:
-	elf_end(elf);
-	pr_debug("unwind: elf_is_exec(%s): %d\n", name, retval);
-	return retval;
-}
-#endif
-
-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[];
-} __packed;
-
-static int unwind_spec_ehframe(struct dso *dso, struct machine *machine,
-			       u64 offset, u64 *table_data_offset, 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);
-	*table_data_offset = enc - (u8 *) &hdr;
-	return 0;
-}
-
-struct read_unwind_spec_eh_frame_maps_cb_args {
-	struct dso *dso;
-	u64 base_addr;
-};
-
-static int read_unwind_spec_eh_frame_maps_cb(struct map *map, void *data)
-{
-
-	struct read_unwind_spec_eh_frame_maps_cb_args *args = data;
-
-	if (map__dso(map) == args->dso && map__start(map) - map__pgoff(map) < args->base_addr)
-		args->base_addr = map__start(map) - map__pgoff(map);
-
-	return 0;
-}
-
-
-static int read_unwind_spec_eh_frame(struct dso *dso, struct unwind_info *ui,
-				     u64 *table_data, u64 *segbase,
-				     u64 *fde_count)
-{
-	struct read_unwind_spec_eh_frame_maps_cb_args args = {
-		.dso = dso,
-		.base_addr = UINT64_MAX,
-	};
-	int ret, fd;
-
-	if (dso__data(dso)->eh_frame_hdr_offset == 0) {
-		fd = dso__data_get_fd(dso, ui->machine);
-		if (fd < 0)
-			return -EINVAL;
-
-		/* Check the .eh_frame section for unwinding info */
-		ret = elf_section_address_and_offset(fd, ".eh_frame_hdr",
-						     &dso__data(dso)->eh_frame_hdr_addr,
-						     &dso__data(dso)->eh_frame_hdr_offset);
-		dso__data(dso)->elf_base_addr = elf_base_address(fd);
-		dso__data_put_fd(dso);
-		if (ret || dso__data(dso)->eh_frame_hdr_offset == 0)
-			return -EINVAL;
-	}
-
-	maps__for_each_map(thread__maps(ui->thread), read_unwind_spec_eh_frame_maps_cb, &args);
-
-	args.base_addr -= dso__data(dso)->elf_base_addr;
-	/* Address of .eh_frame_hdr */
-	*segbase = args.base_addr + dso__data(dso)->eh_frame_hdr_addr;
-	ret = unwind_spec_ehframe(dso, ui->machine, dso__data(dso)->eh_frame_hdr_offset,
-				   table_data, fde_count);
-	if (ret)
-		return ret;
-	/* binary_search_table offset plus .eh_frame_hdr address */
-	*table_data += *segbase;
-	return 0;
-}
-
-#ifndef NO_LIBUNWIND_DEBUG_FRAME
-static int read_unwind_spec_debug_frame(struct dso *dso,
-					struct machine *machine, u64 *offset)
-{
-	int fd;
-	u64 ofs = dso__data(dso)->debug_frame_offset;
-
-	/* debug_frame can reside in:
-	 *  - dso
-	 *  - debug pointed by symsrc_filename
-	 *  - gnu_debuglink, which doesn't necessary
-	 *    has to be pointed by symsrc_filename
-	 */
-	if (ofs == 0) {
-		fd = dso__data_get_fd(dso, machine);
-		if (fd >= 0) {
-			ofs = elf_section_offset(fd, ".debug_frame");
-			dso__data_put_fd(dso);
-		}
-
-		if (ofs <= 0) {
-			fd = open(dso__symsrc_filename(dso), O_RDONLY);
-			if (fd >= 0) {
-				ofs = elf_section_offset(fd, ".debug_frame");
-				close(fd);
-			}
-		}
-
-		if (ofs <= 0) {
-			char *debuglink = malloc(PATH_MAX);
-			int ret = 0;
-
-			if (debuglink == NULL) {
-				pr_err("unwind: Can't read unwind spec debug frame.\n");
-				return -ENOMEM;
-			}
-
-			ret = dso__read_binary_type_filename(
-				dso, DSO_BINARY_TYPE__DEBUGLINK,
-				machine->root_dir, debuglink, PATH_MAX);
-			if (!ret) {
-				fd = open(debuglink, O_RDONLY);
-				if (fd >= 0) {
-					ofs = elf_section_offset(fd,
-							".debug_frame");
-					close(fd);
-				}
-			}
-			if (ofs > 0) {
-				if (dso__symsrc_filename(dso) != NULL) {
-					pr_warning(
-						"%s: overwrite symsrc(%s,%s)\n",
-							__func__,
-							dso__symsrc_filename(dso),
-							debuglink);
-					dso__free_symsrc_filename(dso);
-				}
-				dso__set_symsrc_filename(dso, debuglink);
-			} else {
-				free(debuglink);
-			}
-		}
-
-		dso__data(dso)->debug_frame_offset = ofs;
-	}
-
-	*offset = ofs;
-	if (*offset)
-		return 0;
-
-	return -EINVAL;
-}
-#endif
-
-static struct map *find_map(unw_word_t ip, struct unwind_info *ui)
-{
-	struct addr_location al;
-	struct map *ret;
-
-	addr_location__init(&al);
-	thread__find_map(ui->thread, PERF_RECORD_MISC_USER, ip, &al);
-	ret = map__get(al.map);
-	addr_location__exit(&al);
-	return ret;
-}
-
-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;
-	struct dso *dso;
-	unw_dyn_info_t di;
-	u64 table_data, segbase, fde_count;
-	int ret = -EINVAL;
-
-	map = find_map(ip, ui);
-	if (!map)
-		return -EINVAL;
-
-	dso = map__dso(map);
-	if (!dso) {
-		map__put(map);
-		return -EINVAL;
-	}
-
-	pr_debug("unwind: find_proc_info dso %s\n", dso__name(dso));
-
-	/* Check the .eh_frame section for unwinding info */
-	if (!read_unwind_spec_eh_frame(dso, ui, &table_data, &segbase, &fde_count)) {
-		memset(&di, 0, sizeof(di));
-		di.format   = UNW_INFO_FORMAT_REMOTE_TABLE;
-		di.start_ip = map__start(map);
-		di.end_ip   = map__end(map);
-		di.u.rti.segbase    = segbase;
-		di.u.rti.table_data = table_data;
-		di.u.rti.table_len  = fde_count * sizeof(struct table_entry)
-				      / sizeof(unw_word_t);
-		ret = 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 (ret < 0 &&
-	    !read_unwind_spec_debug_frame(dso, ui->machine, &segbase)) {
-		int fd = dso__data_get_fd(dso, ui->machine);
-		int is_exec = elf_is_exec(fd, dso__name(dso));
-		u64 start = map__start(map);
-		unw_word_t base = is_exec ? 0 : start;
-		const char *symfile;
-
-		if (fd >= 0)
-			dso__data_put_fd(dso);
-
-		symfile = dso__symsrc_filename(dso) ?: dso__name(dso);
-
-		memset(&di, 0, sizeof(di));
-		if (dwarf_find_debug_frame(0, &di, ip, base, symfile, start, map__end(map)))
-			ret = dwarf_search_unwind_table(as, ip, &di, pi,
-							need_unwind_info, arg);
-	}
-#endif
-	map__put(map);
-	return ret;
-}
-
-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 map *map;
-	struct dso *dso;
-	ssize_t size;
-
-	map = find_map(addr, ui);
-	if (!map) {
-		pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
-		return -1;
-	}
-
-	dso = map__dso(map);
-
-	if (!dso) {
-		map__put(map);
-		return -1;
-	}
-
-	size = dso__data_read_addr(dso, map, ui->machine,
-				   addr, (u8 *) data, sizeof(*data));
-	map__put(map);
-	return !(size == sizeof(*data));
-}
-
-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;
-	const char *arch = perf_env__arch(ui->machine->env);
-	struct stack_dump *stack = &ui->sample->user_stack;
-	u64 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 = perf_reg_value(&start, &ui->sample->user_regs,
-			     perf_arch_reg_sp(arch));
-	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"
-				 " 0x%" PRIx64 "-0x%" PRIx64 "\n",
-				 (void *) (uintptr_t) addr, start, 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 *) (uintptr_t) 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;
-	u64 val;
-
-	/* 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 = LIBUNWIND__ARCH_REG_ID(regnum);
-	if (id < 0)
-		return -EINVAL;
-
-	ret = perf_reg_value(&val, &ui->sample->user_regs, id);
-	if (ret) {
-		if (!ui->best_effort)
-			pr_err("unwind: can't read reg %d\n", regnum);
-		return ret;
-	}
-
-	*valp = (unw_word_t) val;
-	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,
-		 unwind_entry_cb_t cb, void *arg)
-{
-	struct unwind_entry e;
-	struct addr_location al;
-	int ret;
-
-	addr_location__init(&al);
-	e.ms.sym = thread__find_symbol(thread, PERF_RECORD_MISC_USER, ip, &al);
-	e.ip     = ip;
-	e.ms.map = al.map;
-	e.ms.maps = al.maps;
-
-	pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
-		 al.sym ? al.sym->name : "''",
-		 ip,
-		 al.map ? map__map_ip(al.map, ip) : (u64) 0);
-
-	ret = cb(&e, arg);
-	addr_location__exit(&al);
-	return ret;
-}
-
-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 _unwind__prepare_access(struct maps *maps)
-{
-	void *addr_space = unw_create_addr_space(&accessors, 0);
-
-	maps__set_addr_space(maps, addr_space);
-	if (!addr_space) {
-		pr_err("unwind: Can't create unwind address space.\n");
-		return -ENOMEM;
-	}
-
-	unw_set_caching_policy(addr_space, UNW_CACHE_GLOBAL);
-	return 0;
-}
-
-static void _unwind__flush_access(struct maps *maps)
-{
-	unw_flush_cache(maps__addr_space(maps), 0, 0);
-}
-
-static void _unwind__finish_access(struct maps *maps)
-{
-	unw_destroy_addr_space(maps__addr_space(maps));
-}
-
-static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
-		       void *arg, int max_stack)
-{
-	const char *arch = perf_env__arch(ui->machine->env);
-	u64 val;
-	unw_word_t ips[max_stack];
-	unw_addr_space_t addr_space;
-	unw_cursor_t c;
-	int ret, i = 0;
-
-	ret = perf_reg_value(&val, &ui->sample->user_regs,
-			     perf_arch_reg_ip(arch));
-	if (ret)
-		return ret;
-
-	ips[i++] = (unw_word_t) val;
-
-	/*
-	 * If we need more than one entry, do the DWARF
-	 * unwind itself.
-	 */
-	if (max_stack - 1 > 0) {
-		WARN_ONCE(!ui->thread, "WARNING: ui->thread is NULL");
-		addr_space = maps__addr_space(thread__maps(ui->thread));
-
-		if (addr_space == NULL)
-			return -1;
-
-		ret = unw_init_remote(&c, addr_space, ui);
-		if (ret && !ui->best_effort)
-			display_error(ret);
-
-		while (!ret && (unw_step(&c) > 0) && i < max_stack) {
-			unw_get_reg(&c, UNW_REG_IP, &ips[i]);
-
-			/*
-			 * Decrement the IP for any non-activation frames.
-			 * this is required to properly find the srcline
-			 * for caller frames.
-			 * See also the documentation for dwfl_frame_pc(),
-			 * which this code tries to replicate.
-			 */
-			if (unw_is_signal_frame(&c) <= 0)
-				--ips[i];
-
-			++i;
-		}
-
-		max_stack = i;
-	}
-
-	/*
-	 * Display what we got based on the order setup.
-	 */
-	for (i = 0; i < max_stack && !ret; i++) {
-		int j = i;
-
-		if (callchain_param.order == ORDER_CALLER)
-			j = max_stack - i - 1;
-		ret = ips[j] ? entry(ips[j], ui->thread, cb, arg) : 0;
-	}
-
-	return ret;
-}
-
-static int _unwind__get_entries(unwind_entry_cb_t cb, void *arg,
-			struct thread *thread,
-			struct perf_sample *data, int max_stack,
-			bool best_effort)
-{
-	struct unwind_info ui = {
-		.sample       = data,
-		.thread       = thread,
-		.machine      = maps__machine(thread__maps(thread)),
-		.best_effort  = best_effort
-	};
-
-	if (!data->user_regs.regs)
-		return -EINVAL;
-
-	if (max_stack <= 0)
-		return -EINVAL;
-
-	return get_entries(&ui, cb, arg, max_stack);
-}
-
-static struct unwind_libunwind_ops
-_unwind_libunwind_ops = {
-	.prepare_access = _unwind__prepare_access,
-	.flush_access   = _unwind__flush_access,
-	.finish_access  = _unwind__finish_access,
-	.get_entries    = _unwind__get_entries,
-};
-
-#ifndef REMOTE_UNWIND_LIBUNWIND
-struct unwind_libunwind_ops *
-local_unwind_libunwind_ops = &_unwind_libunwind_ops;
-#endif