Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1211084
| From | Wang Nan <wangnan0@huawei.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 21/29] perf tools: Introduce arch_get_reg_info() for x86 |
| Date | 2015-08-21 12:20 +0200 |
| Message-ID | <pZRAv-DT-37@gated-at.bofh.it> (permalink) |
| References | <pZRAt-DT-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
From: He Kuang <hekuang@huawei.com>
arch_get_reg_info() is a helper function which converts register name
like "%rax" to offset of a register in 'struct pt_regs', which is
required by BPF prologue generator.
This patch replaces original string table by a 'struct reg_info' table,
which records offset of registers according to its name.
For x86, since there are two sub-archs (x86_32 and x86_64) but we can
only get pt_regs for the arch we are currently on, this patch fills
offset with '-1' for another sub-arch. This introduces a limitation to
perf prologue that, we are unable to generate prologue on a x86_32
compiled perf for BPF programs targeted on x86_64 kernel. This
limitation is acceptable, because this is a very rare usecase.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: He Kuang <hekuang@huawei.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/n/1436445342-1402-34-git-send-email-wangnan0@huawei.com
---
tools/perf/arch/x86/Makefile | 1 +
tools/perf/arch/x86/util/Build | 2 +
tools/perf/arch/x86/util/dwarf-regs.c | 104 ++++++++++++++++++++++++----------
3 files changed, 78 insertions(+), 29 deletions(-)
diff --git a/tools/perf/arch/x86/Makefile b/tools/perf/arch/x86/Makefile
index 21322e0..a84a6f6f 100644
--- a/tools/perf/arch/x86/Makefile
+++ b/tools/perf/arch/x86/Makefile
@@ -2,3 +2,4 @@ ifndef NO_DWARF
PERF_HAVE_DWARF_REGS := 1
endif
HAVE_KVM_STAT_SUPPORT := 1
+PERF_HAVE_ARCH_GET_REG_INFO := 1
diff --git a/tools/perf/arch/x86/util/Build b/tools/perf/arch/x86/util/Build
index a8be9f9..a3837f5 100644
--- a/tools/perf/arch/x86/util/Build
+++ b/tools/perf/arch/x86/util/Build
@@ -3,6 +3,8 @@ libperf-y += tsc.o
libperf-y += pmu.o
libperf-y += kvm-stat.o
+# BPF_PROLOGUE also need dwarf-regs.o. However, if CONFIG_BPF_PROLOGUE
+# is true, CONFIG_DWARF must true.
libperf-$(CONFIG_DWARF) += dwarf-regs.o
libperf-$(CONFIG_LIBUNWIND) += unwind-libunwind.o
diff --git a/tools/perf/arch/x86/util/dwarf-regs.c b/tools/perf/arch/x86/util/dwarf-regs.c
index be22dd4..9928caf 100644
--- a/tools/perf/arch/x86/util/dwarf-regs.c
+++ b/tools/perf/arch/x86/util/dwarf-regs.c
@@ -22,44 +22,67 @@
#include <stddef.h>
#include <dwarf-regs.h>
+#include <string.h>
+#include <linux/ptrace.h>
+#include <linux/kernel.h> /* for offsetof */
+#include <util/bpf-loader.h>
+
+struct reg_info {
+ const char *name; /* Reg string in debuginfo */
+ int offset; /* Reg offset in struct pt_regs */
+};
/*
* Generic dwarf analysis helpers
*/
-
+/*
+ * x86_64 compiling can't access pt_regs for x86_32, so fill offset
+ * with -1.
+ */
+#ifdef __x86_64__
+# define REG_INFO(n, f) { .name = n, .offset = -1, }
+#else
+# define REG_INFO(n, f) { .name = n, .offset = offsetof(struct pt_regs, f), }
+#endif
#define X86_32_MAX_REGS 8
-const char *x86_32_regs_table[X86_32_MAX_REGS] = {
- "%ax",
- "%cx",
- "%dx",
- "%bx",
- "$stack", /* Stack address instead of %sp */
- "%bp",
- "%si",
- "%di",
+
+struct reg_info x86_32_regs_table[X86_32_MAX_REGS] = {
+ REG_INFO("%ax", eax),
+ REG_INFO("%cx", ecx),
+ REG_INFO("%dx", edx),
+ REG_INFO("%bx", ebx),
+ REG_INFO("$stack", esp), /* Stack address instead of %sp */
+ REG_INFO("%bp", ebp),
+ REG_INFO("%si", esi),
+ REG_INFO("%di", edi),
};
+#undef REG_INFO
+#ifdef __x86_64__
+# define REG_INFO(n, f) { .name = n, .offset = offsetof(struct pt_regs, f), }
+#else
+# define REG_INFO(n, f) { .name = n, .offset = -1, }
+#endif
#define X86_64_MAX_REGS 16
-const char *x86_64_regs_table[X86_64_MAX_REGS] = {
- "%ax",
- "%dx",
- "%cx",
- "%bx",
- "%si",
- "%di",
- "%bp",
- "%sp",
- "%r8",
- "%r9",
- "%r10",
- "%r11",
- "%r12",
- "%r13",
- "%r14",
- "%r15",
+struct reg_info x86_64_regs_table[X86_64_MAX_REGS] = {
+ REG_INFO("%ax", rax),
+ REG_INFO("%dx", rdx),
+ REG_INFO("%cx", rcx),
+ REG_INFO("%bx", rbx),
+ REG_INFO("%si", rsi),
+ REG_INFO("%di", rdi),
+ REG_INFO("%bp", rbp),
+ REG_INFO("%sp", rsp),
+ REG_INFO("%r8", r8),
+ REG_INFO("%r9", r9),
+ REG_INFO("%r10", r10),
+ REG_INFO("%r11", r11),
+ REG_INFO("%r12", r12),
+ REG_INFO("%r13", r13),
+ REG_INFO("%r14", r14),
+ REG_INFO("%r15", r15),
};
-/* TODO: switching by dwarf address size */
#ifdef __x86_64__
#define ARCH_MAX_REGS X86_64_MAX_REGS
#define arch_regs_table x86_64_regs_table
@@ -71,5 +94,28 @@ const char *x86_64_regs_table[X86_64_MAX_REGS] = {
/* Return architecture dependent register string (for kprobe-tracer) */
const char *get_arch_regstr(unsigned int n)
{
- return (n <= ARCH_MAX_REGS) ? arch_regs_table[n] : NULL;
+ return (n <= ARCH_MAX_REGS) ? arch_regs_table[n].name : NULL;
}
+
+#ifdef HAVE_BPF_PROLOGUE
+int arch_get_reg_info(const char *name, int *offset)
+{
+ int i;
+ struct reg_info *info;
+
+ if (!name || !offset)
+ return -1;
+
+ for (i = 0; i < ARCH_MAX_REGS; i++) {
+ info = &arch_regs_table[i];
+ if (strcmp(info->name, name) == 0) {
+ if (info->offset < 0)
+ return -1;
+ *offset = info->offset;
+ return 0;
+ }
+ }
+
+ return -1;
+}
+#endif
--
2.1.0
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[GIT PULL 00/29] perf tools: filtering events using eBPF programs Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 25/29] perf record: Support custom vmlinux path Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 14/29] perf tests: Enforce LLVM test for BPF test Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 18/29] perf probe: Reset args and nargs for probe_trace_event when failure Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 11/29] perf tools: Suppress probing messages when probing by BPF loading Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 13/29] perf tools: Infrastructure for compiling scriptlets when passing '.c' to --event Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 19/29] perf tools: Move linux/filter.h to tools/include Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 05/29] perf probe: Attach trace_probe_event with perf_probe_event Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 21/29] perf tools: Introduce arch_get_reg_info() for x86 Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 03/29] perf ebpf: Add the libbpf glue Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 10/29] perf tools: Attach eBPF program to perf event Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 01/29] perf probe: Try to use symbol table if searching debug info failed Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
Re: [PATCH 01/29] perf probe: Try to use symbol table if searching debug info failed Arnaldo Carvalho de Melo <acme@redhat.com> - 2015-08-21 16:20 +0200
[tip:perf/core] perf probe: Try to use symbol table if searching debug info failed tip-bot for Wang Nan <tipbot@zytor.com> - 2015-08-22 09:00 +0200
[PATCH 16/29] bpf tools: Load a program with different instances using preprocessor Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 07/29] perf bpf: Collect 'struct perf_probe_event' for bpf_program Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 04/29] perf tools: Enable passing bpf object file to --event Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 20/29] perf tools: Add BPF_PROLOGUE config options for further patches Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 24/29] perf tools: Use same BPF program if arguments are identical Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 23/29] perf tools: Generate prologue for BPF programs Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 02/29] perf tools: Make perf depend on libbpf Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 29/29] bpf: Introduce function for outputing data to perf event Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 12/29] perf record: Add clang options for compiling BPF scripts Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 06/29] perf record, bpf: Parse and probe eBPF programs probe points Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 27/29] perf tools: Support attach BPF program on uprobe events Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 17/29] perf tools: Fix probe-event.h include Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 28/29] tools lib traceevent: Support function __get_dynamic_array_len Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
Re: [PATCH 28/29] tools lib traceevent: Support function __get_dynamic_array_len Arnaldo Carvalho de Melo <acme@redhat.com> - 2015-08-21 18:10 +0200
[PATCH 15/29] perf test: Add 'perf test BPF' Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 08/29] perf record: Load all eBPF object into kernel Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:30 +0200
csiph-web