perf callchain: Separate libunwind code to special object
authorJiri Olsa <jolsa@redhat.com>
Tue, 7 Jan 2014 12:47:26 +0000 (13:47 +0100)
committerArnaldo Carvalho de Melo <acme@redhat.com>
Tue, 18 Feb 2014 12:34:48 +0000 (09:34 -0300)
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>
Acked-by: Jean Pihet <jean.pihet@linaro.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1389098853-14466-10-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
tools/perf/Makefile.perf
tools/perf/arch/arm/Makefile
tools/perf/arch/arm/util/unwind-libunwind.c [new file with mode: 0644]
tools/perf/arch/arm/util/unwind.c [deleted file]
tools/perf/arch/x86/Makefile
tools/perf/arch/x86/util/unwind-libunwind.c [new file with mode: 0644]
tools/perf/arch/x86/util/unwind.c [deleted file]
tools/perf/util/unwind-libunwind.c [new file with mode: 0644]
tools/perf/util/unwind.c [deleted file]

index 10fcf331e0e36a1be660eeff15bd5189e11bf9c2..9ef6b33bcfe32f099a1fcde743e845d5378c4fe9 100644 (file)
@@ -481,7 +481,7 @@ 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
 
index fe9b61e322a557b063ecc78eccb9a87c8de73dda..67e9b3d38e89209dec2810a9ca229127fd49f17c 100644 (file)
@@ -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 (file)
index 0000000..da3dc95
--- /dev/null
@@ -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 (file)
index da3dc95..0000000
+++ /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;
-}
index 948ea6cfd681d3b832c03daaaaf00de1fb4f4172..4fa9be983ad11ebd51e6150de7c7045180c7aa9e 100644 (file)
@@ -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 (file)
index 0000000..456a88c
--- /dev/null
@@ -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 (file)
index 456a88c..0000000
+++ /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 (file)
index 0000000..720a4ca
--- /dev/null
@@ -0,0 +1,595 @@
+/*
+ * 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 "symbol.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 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, NULL))
+                       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));
+               if (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 (file)
index 720a4ca..0000000
+++ /dev/null
@@ -1,595 +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 "symbol.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 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, NULL))
-                       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));
-               if (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;
-}