Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752844AbcLFHPo (ORCPT ); Tue, 6 Dec 2016 02:15:44 -0500 Received: from szxga02-in.huawei.com ([119.145.14.65]:46135 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752432AbcLFHOp (ORCPT ); Tue, 6 Dec 2016 02:14:45 -0500 From: Wang Nan To: CC: , , Wang Nan , Arnaldo Carvalho de Melo , "Alexei Starovoitov" , He Kuang , Jiri Olsa , Zefan Li , Subject: [PATCH v4 11/18] perf clang jit: Collect the lowest address in maps section as map_base Date: Tue, 6 Dec 2016 07:13:49 +0000 Message-ID: <20161206071356.5312-12-wangnan0@huawei.com> X-Mailer: git-send-email 2.10.1 In-Reply-To: <20161206071356.5312-1-wangnan0@huawei.com> References: <20161206071356.5312-1-wangnan0@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.193.248] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5874 Lines: 202 During jitting, find the lowest address in maps section and store its value to _map_base. Pass its value out through perf_clang__compile_bpf(). map_base is useful for jitted functions accessing BPF maps. Signed-off-by: Wang Nan Cc: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: He Kuang Cc: Jiri Olsa Cc: Zefan Li Cc: pi3orama@163.com --- tools/perf/util/bpf-loader.c | 39 +++++++++++++++++++++++++++++++++++++-- tools/perf/util/c++/clang-c.h | 6 ++++-- tools/perf/util/c++/clang.cpp | 15 +++++++++++++-- tools/perf/util/c++/clang.h | 5 +++++ 4 files changed, 59 insertions(+), 6 deletions(-) diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index bf61a6f..9a0c33d 100644 --- a/tools/perf/util/bpf-loader.c +++ b/tools/perf/util/bpf-loader.c @@ -47,6 +47,10 @@ struct bpf_prog_priv { int *type_mapping; }; +struct bpf_obj_priv { + void *map_base; +}; + static bool libbpf_initialized; struct bpf_object * @@ -70,9 +74,20 @@ bpf__prepare_load_buffer(void *obj_buf, size_t obj_buf_sz, const char *name) return obj; } +static void +clear_obj_priv(struct bpf_object *obj __maybe_unused, + void *_priv) +{ + struct bpf_obj_priv *priv = _priv; + + free(priv); +} + struct bpf_object *bpf__prepare_load(const char *filename, bool source) { struct bpf_object *obj; + void *map_base = NULL; + int err; if (!libbpf_initialized) { libbpf_set_print(libbpf_warning, @@ -82,14 +97,14 @@ struct bpf_object *bpf__prepare_load(const char *filename, bool source) } if (source) { - int err; void *obj_buf; size_t obj_buf_sz; jitted_funcs_map_t jitted_funcs_map; perf_clang__init(); err = perf_clang__compile_bpf(filename, &obj_buf, - &obj_buf_sz, &jitted_funcs_map); + &obj_buf_sz, &jitted_funcs_map, + &map_base); perf_clang__cleanup(); if (err) { pr_warning("bpf: builtin compilation failed: %d, try external compiler\n", err); @@ -119,7 +134,27 @@ struct bpf_object *bpf__prepare_load(const char *filename, bool source) return obj; } + if (map_base) { + struct bpf_obj_priv *priv = calloc(sizeof(*priv), 1); + + if (!priv) { + pr_debug("bpf: failed to alloc priv for object\n"); + err = -ENOMEM; + goto errout; + } + priv->map_base = map_base; + + err = bpf_object__set_priv(obj, priv, clear_obj_priv); + if (err) { + pr_debug("Failed to set priv for object '%s'\n", filename); + goto errout; + } + } + return obj; +errout: + bpf_object__close(obj); + return ERR_PTR(err); } void bpf__clear(void) diff --git a/tools/perf/util/c++/clang-c.h b/tools/perf/util/c++/clang-c.h index 021b1ad..4cf651b 100644 --- a/tools/perf/util/c++/clang-c.h +++ b/tools/perf/util/c++/clang-c.h @@ -22,7 +22,8 @@ extern void test__clang_callback(int x); extern int perf_clang__compile_bpf(const char *filename, void **p_obj_buf, size_t *p_obj_buf_sz, - jitted_funcs_map_t *p_funcs_map); + jitted_funcs_map_t *p_funcs_map, + void **p_map_base); extern int perf_clang__hook_jitted_func(jitted_funcs_map_t map, void *ctx, bool is_err); @@ -40,7 +41,8 @@ static inline int perf_clang__compile_bpf(const char *filename __maybe_unused, void **p_obj_buf __maybe_unused, size_t *p_obj_buf_sz __maybe_unused, - jitted_funcs_map_t *p_funcs_map __maybe_unused) + jitted_funcs_map_t *p_funcs_map __maybe_unused, + void **p_map_base __maybe_unused) { return -ENOTSUP; } diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp index 4a98597..684855c 100644 --- a/tools/perf/util/c++/clang.cpp +++ b/tools/perf/util/c++/clang.cpp @@ -119,7 +119,7 @@ getModuleFromSource(llvm::opt::ArgStringList CFlags, StringRef Path) return getModuleFromSource(std::move(CFlags), Path, VFS); } -PerfModule::PerfModule(std::unique_ptr&& M) : Module(std::move(M)) +PerfModule::PerfModule(std::unique_ptr&& M) : Module(std::move(M)), _map_base(NULL) { for (llvm::Function& F : *Module) { if (F.getLinkage() != llvm::GlobalValue::ExternalLinkage) @@ -250,6 +250,13 @@ int PerfModule::doJIT(void) &JITMemoryManager, std::move(Resolver)); + void *map_base = NULL; + for (llvm::GlobalValue *map : Maps) { + JITSymbol sym = CompileLayer.findSymbol(map->getName().str(), true); + void *address = (void *)(intptr_t)sym.getAddress(); + if (!map_base || address < map_base) + map_base = address; + } for (Function *F : JITFunctions) { JITSymbol sym = CompileLayer.findSymbol(F->getName().str(), true); @@ -269,6 +276,7 @@ int PerfModule::doJIT(void) << hook << ", only one is used\n"; JITResult[hook] = func; } + _map_base = map_base; return 0; } @@ -392,7 +400,8 @@ void perf_clang__cleanup(void) int perf_clang__compile_bpf(const char *_filename, void **p_obj_buf, size_t *p_obj_buf_sz, - jitted_funcs_map_t *p_funcs_map) + jitted_funcs_map_t *p_funcs_map, + void **p_map_base) { using namespace perf; @@ -425,6 +434,8 @@ int perf_clang__compile_bpf(const char *_filename, if (p_funcs_map) *p_funcs_map = (jitted_funcs_map_t)(M->copyJITResult()); + if (p_map_base) + *p_map_base = M->getMapBase(); return 0; } diff --git a/tools/perf/util/c++/clang.h b/tools/perf/util/c++/clang.h index df2eb8f..aacedc2 100644 --- a/tools/perf/util/c++/clang.h +++ b/tools/perf/util/c++/clang.h @@ -26,6 +26,7 @@ class PerfModule { std::set JITFunctions; HookMap JITResult; + void *_map_base; void prepareBPF(void); void prepareJIT(void); @@ -38,6 +39,10 @@ class PerfModule { { return new HookMap(JITResult); } + inline void *getMapBase(void) + { + return _map_base; + } PerfModule(std::unique_ptr&& M); -- 2.10.1