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Date: Wed, 31 Aug 2016 17:54:11 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Masami Hiramatsu <mhiramat@...nel.org>
Cc: linux-kernel@...r.kernel.org,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>, Jiri Olsa <jolsa@...hat.com>
Subject: Re: [PATCH v2 3/3] perf-probe: Support probing on offline cross-arch
binary
Em Fri, Aug 26, 2016 at 01:24:57AM +0900, Masami Hiramatsu escreveu:
> 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 event by "copy & paste" from
> ./tracing/kprobe_events to target-machine's debugfs/tracing/kprobe_events
Fixing the example not to refer to "tracing/kprobe_events", as it is not
there anymore, instead append what '--definition' produced to the target
machine <tracefs mountpoint>/tracing/kprobe_events file.
- Arnaldo
> Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
> ---
> Changes from v1:
> - Change the example.
> ---
> tools/perf/arch/arm/include/dwarf-regs-table.h | 9 +++
> tools/perf/arch/arm64/include/dwarf-regs-table.h | 13 +++++
> tools/perf/arch/powerpc/include/dwarf-regs-table.h | 27 ++++++++++
> tools/perf/arch/s390/include/dwarf-regs-table.h | 8 +++
> tools/perf/arch/sh/include/dwarf-regs-table.h | 25 +++++++++
> tools/perf/arch/sparc/include/dwarf-regs-table.h | 18 +++++++
> tools/perf/arch/x86/include/dwarf-regs-table.h | 14 +++++
> tools/perf/arch/xtensa/include/dwarf-regs-table.h | 8 +++
> tools/perf/util/Build | 1
> tools/perf/util/dwarf-regs.c | 55 ++++++++++++++++++++
> tools/perf/util/include/dwarf-regs.h | 6 ++
> tools/perf/util/probe-finder.c | 27 ++++++----
> tools/perf/util/probe-finder.h | 1
> 13 files changed, 201 insertions(+), 11 deletions(-)
> create mode 100644 tools/perf/arch/arm/include/dwarf-regs-table.h
> create mode 100644 tools/perf/arch/arm64/include/dwarf-regs-table.h
> create mode 100644 tools/perf/arch/powerpc/include/dwarf-regs-table.h
> create mode 100644 tools/perf/arch/s390/include/dwarf-regs-table.h
> create mode 100644 tools/perf/arch/sh/include/dwarf-regs-table.h
> create mode 100644 tools/perf/arch/sparc/include/dwarf-regs-table.h
> create mode 100644 tools/perf/arch/x86/include/dwarf-regs-table.h
> create mode 100644 tools/perf/arch/xtensa/include/dwarf-regs-table.h
> create mode 100644 tools/perf/util/dwarf-regs.c
>
> 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
> 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
> 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
> 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
> 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
> 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
> 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
> 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
> 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
> --- 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
> index 0000000..ce15816
> --- /dev/null
> +++ b/tools/perf/util/dwarf-regs.c
> @@ -0,0 +1,55 @@
> +/*
> + * dwarf-regs.c : Mapping of DWARF debug register numbers into register names.
> + *
> + * Written by: Masami Hiramatsu <mhiramat@...nel.org>
> + */
> +
> +#include <util.h>
> +#include <debug.h>
> +#include <dwarf-regs.h>
> +#include <elf.h>
> +
> +/* 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
> --- 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
> --- 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
> --- 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 */
> };
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