perf probe: Support probing on offline cross-arch binary

Support probing on offline cross-architecture binary by adding getting
the target machine arch from ELF and choose correct register string for
the machine.

Here is an example:
  -----
  $ perf probe --vmlinux=./vmlinux-arm --definition 'do_sys_open $params'
  p:probe/do_sys_open do_sys_open+0 dfd=%r5:s32 filename=%r1:u32 flags=%r6:s32 mode=%r3:u16
  -----

Here, we can get probe/do_sys_open from above and append it to to the target
machine's tracing/kprobe_events file in the tracefs mountput, usually
/sys/kernel/debug/tracing/kprobe_events (or /sys/kernel/tracing/kprobe_events).

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/147214229717.23638.6440579792548044658.stgit@devbox
[ Add definition for EM_AARCH64 to fix the build on at least centos 6, debian 7 & ubuntu 12.04.5 ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/arch/arm/include/dwarf-regs-table.h b/tools/perf/arch/arm/include/dwarf-regs-table.h
new file mode 100644 (file)
index 0000000..f298d03
--- /dev/null
+++ b/tools/perf/arch/arm/include/dwarf-regs-table.h
@@ -0,0 +1,9 @@
+#ifdef DEFINE_DWARF_REGSTR_TABLE
+/* This is included in perf/util/dwarf-regs.c */
+
+static const char * const arm_regstr_tbl[] = {
+       "%r0", "%r1", "%r2", "%r3", "%r4",
+       "%r5", "%r6", "%r7", "%r8", "%r9", "%r10",
+       "%fp", "%ip", "%sp", "%lr", "%pc",
+};
+#endif

diff --git a/tools/perf/arch/arm64/include/dwarf-regs-table.h b/tools/perf/arch/arm64/include/dwarf-regs-table.h
new file mode 100644 (file)
index 0000000..2675936
--- /dev/null
+++ b/tools/perf/arch/arm64/include/dwarf-regs-table.h
@@ -0,0 +1,13 @@
+#ifdef DEFINE_DWARF_REGSTR_TABLE
+/* This is included in perf/util/dwarf-regs.c */
+
+static const char * const aarch64_regstr_tbl[] = {
+       "%r0", "%r1", "%r2", "%r3", "%r4",
+       "%r5", "%r6", "%r7", "%r8", "%r9",
+       "%r10", "%r11", "%r12", "%r13", "%r14",
+       "%r15", "%r16", "%r17", "%r18", "%r19",
+       "%r20", "%r21", "%r22", "%r23", "%r24",
+       "%r25", "%r26", "%r27", "%r28", "%r29",
+       "%lr", "%sp",
+};
+#endif

diff --git a/tools/perf/arch/powerpc/include/dwarf-regs-table.h b/tools/perf/arch/powerpc/include/dwarf-regs-table.h
new file mode 100644 (file)
index 0000000..db4730f
--- /dev/null
+++ b/tools/perf/arch/powerpc/include/dwarf-regs-table.h
@@ -0,0 +1,27 @@
+#ifdef DEFINE_DWARF_REGSTR_TABLE
+/* This is included in perf/util/dwarf-regs.c */
+
+/*
+ * Reference:
+ * http://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi-1.9.html
+ * http://refspecs.linux-foundation.org/elf/elfspec_ppc.pdf
+ */
+#define REG_DWARFNUM_NAME(reg, idx)    [idx] = "%" #reg
+
+static const char * const powerpc_regstr_tbl[] = {
+       "%gpr0", "%gpr1", "%gpr2", "%gpr3", "%gpr4",
+       "%gpr5", "%gpr6", "%gpr7", "%gpr8", "%gpr9",
+       "%gpr10", "%gpr11", "%gpr12", "%gpr13", "%gpr14",
+       "%gpr15", "%gpr16", "%gpr17", "%gpr18", "%gpr19",
+       "%gpr20", "%gpr21", "%gpr22", "%gpr23", "%gpr24",
+       "%gpr25", "%gpr26", "%gpr27", "%gpr28", "%gpr29",
+       "%gpr30", "%gpr31",
+       REG_DWARFNUM_NAME(msr,   66),
+       REG_DWARFNUM_NAME(ctr,   109),
+       REG_DWARFNUM_NAME(link,  108),
+       REG_DWARFNUM_NAME(xer,   101),
+       REG_DWARFNUM_NAME(dar,   119),
+       REG_DWARFNUM_NAME(dsisr, 118),
+};
+
+#endif

diff --git a/tools/perf/arch/s390/include/dwarf-regs-table.h b/tools/perf/arch/s390/include/dwarf-regs-table.h
new file mode 100644 (file)
index 0000000..9da74a9
--- /dev/null
+++ b/tools/perf/arch/s390/include/dwarf-regs-table.h
@@ -0,0 +1,8 @@
+#ifdef DEFINE_DWARF_REGSTR_TABLE
+/* This is included in perf/util/dwarf-regs.c */
+
+static const char * const s390_regstr_tbl[] = {
+       "%r0", "%r1",  "%r2",  "%r3",  "%r4",  "%r5",  "%r6",  "%r7",
+       "%r8", "%r9", "%r10", "%r11", "%r12", "%r13", "%r14", "%r15",
+};
+#endif

diff --git a/tools/perf/arch/sh/include/dwarf-regs-table.h b/tools/perf/arch/sh/include/dwarf-regs-table.h
new file mode 100644 (file)
index 0000000..3a2deaf
--- /dev/null
+++ b/tools/perf/arch/sh/include/dwarf-regs-table.h
@@ -0,0 +1,25 @@
+#ifdef DEFINE_DWARF_REGSTR_TABLE
+/* This is included in perf/util/dwarf-regs.c */
+
+const char * const sh_regstr_tbl[] = {
+       "r0",
+       "r1",
+       "r2",
+       "r3",
+       "r4",
+       "r5",
+       "r6",
+       "r7",
+       "r8",
+       "r9",
+       "r10",
+       "r11",
+       "r12",
+       "r13",
+       "r14",
+       "r15",
+       "pc",
+       "pr",
+};
+
+#endif

diff --git a/tools/perf/arch/sparc/include/dwarf-regs-table.h b/tools/perf/arch/sparc/include/dwarf-regs-table.h
new file mode 100644 (file)
index 0000000..12c0761
--- /dev/null
+++ b/tools/perf/arch/sparc/include/dwarf-regs-table.h
@@ -0,0 +1,18 @@
+#ifdef DEFINE_DWARF_REGSTR_TABLE
+/* This is included in perf/util/dwarf-regs.c */
+
+static const char * const sparc_regstr_tbl[] = {
+       "%g0", "%g1", "%g2", "%g3", "%g4", "%g5", "%g6", "%g7",
+       "%o0", "%o1", "%o2", "%o3", "%o4", "%o5", "%sp", "%o7",
+       "%l0", "%l1", "%l2", "%l3", "%l4", "%l5", "%l6", "%l7",
+       "%i0", "%i1", "%i2", "%i3", "%i4", "%i5", "%fp", "%i7",
+       "%f0", "%f1", "%f2", "%f3", "%f4", "%f5", "%f6", "%f7",
+       "%f8", "%f9", "%f10", "%f11", "%f12", "%f13", "%f14", "%f15",
+       "%f16", "%f17", "%f18", "%f19", "%f20", "%f21", "%f22", "%f23",
+       "%f24", "%f25", "%f26", "%f27", "%f28", "%f29", "%f30", "%f31",
+       "%f32", "%f33", "%f34", "%f35", "%f36", "%f37", "%f38", "%f39",
+       "%f40", "%f41", "%f42", "%f43", "%f44", "%f45", "%f46", "%f47",
+       "%f48", "%f49", "%f50", "%f51", "%f52", "%f53", "%f54", "%f55",
+       "%f56", "%f57", "%f58", "%f59", "%f60", "%f61", "%f62", "%f63",
+};
+#endif

diff --git a/tools/perf/arch/x86/include/dwarf-regs-table.h b/tools/perf/arch/x86/include/dwarf-regs-table.h
new file mode 100644 (file)
index 0000000..39ac7cb
--- /dev/null
+++ b/tools/perf/arch/x86/include/dwarf-regs-table.h
@@ -0,0 +1,14 @@
+#ifdef DEFINE_DWARF_REGSTR_TABLE
+/* This is included in perf/util/dwarf-regs.c */
+
+static const char * const x86_32_regstr_tbl[] = {
+       "%ax", "%cx", "%dx", "%bx", "$stack",/* Stack address instead of %sp */
+       "%bp", "%si", "%di",
+};
+
+static const char * const x86_64_regstr_tbl[] = {
+       "%ax", "dx", "%cx", "%bx", "%si", "%di",
+       "%bp", "%sp", "%r8", "%r9", "%r10", "%r11",
+       "%r12", "%r13", "%r14", "%r15",
+};
+#endif

diff --git a/tools/perf/arch/xtensa/include/dwarf-regs-table.h b/tools/perf/arch/xtensa/include/dwarf-regs-table.h
new file mode 100644 (file)
index 0000000..aa0444a
--- /dev/null
+++ b/tools/perf/arch/xtensa/include/dwarf-regs-table.h
@@ -0,0 +1,8 @@
+#ifdef DEFINE_DWARF_REGSTR_TABLE
+/* This is included in perf/util/dwarf-regs.c */
+
+static const char * const xtensa_regstr_tbl[] = {
+       "a0", "a1", "a2", "a3", "a4", "a5", "a6", "a7",
+       "a8", "a9", "a10", "a11", "a12", "a13", "a14", "a15",
+};
+#endif

diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 91c5f6e..f1a6d17 100644 (file)
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -98,6 +98,7 @@ endif
 
 libperf-$(CONFIG_DWARF) += probe-finder.o
 libperf-$(CONFIG_DWARF) += dwarf-aux.o
+libperf-$(CONFIG_DWARF) += dwarf-regs.o
 
 libperf-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o
 libperf-$(CONFIG_LOCAL_LIBUNWIND)    += unwind-libunwind-local.o

diff --git a/tools/perf/util/dwarf-regs.c b/tools/perf/util/dwarf-regs.c
new file mode 100644 (file)
index 0000000..62bc4a8
--- /dev/null
+++ b/tools/perf/util/dwarf-regs.c
@@ -0,0 +1,59 @@
+/*
+ * dwarf-regs.c : Mapping of DWARF debug register numbers into register names.
+ *
+ * Written by: Masami Hiramatsu <mhiramat@kernel.org>
+ */
+
+#include <util.h>
+#include <debug.h>
+#include <dwarf-regs.h>
+#include <elf.h>
+
+#ifndef EM_AARCH64
+#define EM_AARCH64     183  /* ARM 64 bit */
+#endif
+
+/* Define const char * {arch}_register_tbl[] */
+#define DEFINE_DWARF_REGSTR_TABLE
+#include "../arch/x86/include/dwarf-regs-table.h"
+#include "../arch/arm/include/dwarf-regs-table.h"
+#include "../arch/arm64/include/dwarf-regs-table.h"
+#include "../arch/sh/include/dwarf-regs-table.h"
+#include "../arch/powerpc/include/dwarf-regs-table.h"
+#include "../arch/s390/include/dwarf-regs-table.h"
+#include "../arch/sparc/include/dwarf-regs-table.h"
+#include "../arch/xtensa/include/dwarf-regs-table.h"
+
+#define __get_dwarf_regstr(tbl, n) (((n) < ARRAY_SIZE(tbl)) ? (tbl)[(n)] : NULL)
+
+/* Return architecture dependent register string (for kprobe-tracer) */
+const char *get_dwarf_regstr(unsigned int n, unsigned int machine)
+{
+       switch (machine) {
+       case EM_NONE:   /* Generic arch - use host arch */
+               return get_arch_regstr(n);
+       case EM_386:
+               return __get_dwarf_regstr(x86_32_regstr_tbl, n);
+       case EM_X86_64:
+               return __get_dwarf_regstr(x86_64_regstr_tbl, n);
+       case EM_ARM:
+               return __get_dwarf_regstr(arm_regstr_tbl, n);
+       case EM_AARCH64:
+               return __get_dwarf_regstr(aarch64_regstr_tbl, n);
+       case EM_SH:
+               return __get_dwarf_regstr(sh_regstr_tbl, n);
+       case EM_S390:
+               return __get_dwarf_regstr(s390_regstr_tbl, n);
+       case EM_PPC:
+       case EM_PPC64:
+               return __get_dwarf_regstr(powerpc_regstr_tbl, n);
+       case EM_SPARC:
+       case EM_SPARCV9:
+               return __get_dwarf_regstr(sparc_regstr_tbl, n);
+       case EM_XTENSA:
+               return __get_dwarf_regstr(xtensa_regstr_tbl, n);
+       default:
+               pr_err("ELF MACHINE %x is not supported.\n", machine);
+       }
+       return NULL;
+}

diff --git a/tools/perf/util/include/dwarf-regs.h b/tools/perf/util/include/dwarf-regs.h
index 07c644e..43bfd8d 100644 (file)
--- a/tools/perf/util/include/dwarf-regs.h
+++ b/tools/perf/util/include/dwarf-regs.h
@@ -3,6 +3,12 @@
 
 #ifdef HAVE_DWARF_SUPPORT
 const char *get_arch_regstr(unsigned int n);
+/*
+ * get_dwarf_regstr - Returns ftrace register string from DWARF regnum
+ * n: DWARF register number
+ * machine: ELF machine signature (EM_*)
+ */
+const char *get_dwarf_regstr(unsigned int n, unsigned int machine);
 #endif
 
 #ifdef HAVE_ARCH_REGS_QUERY_REGISTER_OFFSET

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index ac4740f..508b61c 100644 (file)
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -171,6 +171,7 @@ static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
  */
 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
                                     Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
+                                    unsigned int machine,
                                     struct probe_trace_arg *tvar)
 {
        Dwarf_Attribute attr;
@@ -266,7 +267,7 @@ static_var:
        if (!tvar)
                return ret2;
 
-       regs = get_arch_regstr(regn);
+       regs = get_dwarf_regstr(regn, machine);
        if (!regs) {
                /* This should be a bug in DWARF or this tool */
                pr_warning("Mapping for the register number %u "
@@ -543,7 +544,7 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
                 dwarf_diename(vr_die));
 
        ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
-                                       &pf->sp_die, pf->tvar);
+                                       &pf->sp_die, pf->machine, pf->tvar);
        if (ret == -ENOENT || ret == -EINVAL) {
                pr_err("Failed to find the location of the '%s' variable at this address.\n"
                       " Perhaps it has been optimized out.\n"
@@ -1106,11 +1107,8 @@ static int debuginfo__find_probes(struct debuginfo *dbg,
                                  struct probe_finder *pf)
 {
        int ret = 0;
-
-#if _ELFUTILS_PREREQ(0, 142)
        Elf *elf;
        GElf_Ehdr ehdr;
-       GElf_Shdr shdr;
 
        if (pf->cfi_eh || pf->cfi_dbg)
                return debuginfo__find_probe_location(dbg, pf);
@@ -1123,11 +1121,18 @@ static int debuginfo__find_probes(struct debuginfo *dbg,
        if (gelf_getehdr(elf, &ehdr) == NULL)
                return -EINVAL;
 
-       if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
-           shdr.sh_type == SHT_PROGBITS)
-               pf->cfi_eh = dwarf_getcfi_elf(elf);
+       pf->machine = ehdr.e_machine;
+
+#if _ELFUTILS_PREREQ(0, 142)
+       do {
+               GElf_Shdr shdr;
+
+               if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
+                   shdr.sh_type == SHT_PROGBITS)
+                       pf->cfi_eh = dwarf_getcfi_elf(elf);
 
-       pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
+               pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
+       } while (0);
 #endif
 
        ret = debuginfo__find_probe_location(dbg, pf);
@@ -1155,7 +1160,7 @@ static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
            (tag == DW_TAG_variable && vf->vars)) {
                if (convert_variable_location(die_mem, vf->pf->addr,
                                              vf->pf->fb_ops, &pf->sp_die,
-                                             NULL) == 0) {
+                                             pf->machine, NULL) == 0) {
                        vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
                        if (vf->args[vf->nargs].var == NULL) {
                                vf->ret = -ENOMEM;
@@ -1318,7 +1323,7 @@ static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
            tag == DW_TAG_variable) {
                ret = convert_variable_location(die_mem, af->pf.addr,
                                                af->pf.fb_ops, &af->pf.sp_die,
-                                               NULL);
+                                               af->pf.machine, NULL);
                if (ret == 0 || ret == -ERANGE) {
                        int ret2;
                        bool externs = !af->child;

diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index 51137fc..f1d8558 100644 (file)
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -80,6 +80,7 @@ struct probe_finder {
        Dwarf_CFI               *cfi_dbg;
 #endif
        Dwarf_Op                *fb_ops;        /* Frame base attribute */
+       unsigned int            machine;        /* Target machine arch */
        struct perf_probe_arg   *pvar;          /* Current target variable */
        struct probe_trace_arg  *tvar;          /* Current result variable */
 };