Messages in this thread | | | Subject | Re: [PATCH] [RFC V1]s390/perf: fix 'start' address of module's map | From | Songshan Gong <> | Date | Fri, 8 Jul 2016 10:17:30 +0800 |
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在 7/7/2016 9:49 AM, Song Shan Gong 写道: > At preset, when creating module's map, perf gets 'start' address by parsing > 'proc/modules', but it's module base address, isn't the start address of > '.text' section. In most archs, it's OK. But for s390, it places 'GOT' and > 'PLT' relocations before '.text' section. So there exists an offset between > module base address and '.text' section, which will incur wrong symbol > resolution for modules. > > Fix this bug by getting 'start' address of module's map from parsing > '/sys/module/[module name]/sections/.text', not from '/proc/modules'. > > Signed-off-by: Song Shan Gong <gongss@linux.vnet.ibm.com> > --- > tools/perf/arch/s390/util/Build | 2 ++ > tools/perf/arch/s390/util/sym-handling.c | 49 ++++++++++++++++++++++++++++++++ > tools/perf/util/machine.c | 6 ++++ > tools/perf/util/machine.h | 2 ++ > 4 files changed, 59 insertions(+) > create mode 100644 tools/perf/arch/s390/util/sym-handling.c > > diff --git a/tools/perf/arch/s390/util/Build b/tools/perf/arch/s390/util/Build > index 8a61372..5e322ed 100644 > --- a/tools/perf/arch/s390/util/Build > +++ b/tools/perf/arch/s390/util/Build > @@ -2,3 +2,5 @@ libperf-y += header.o > libperf-y += kvm-stat.o > > libperf-$(CONFIG_DWARF) += dwarf-regs.o > + > +libperf-y += sym-handling.o > diff --git a/tools/perf/arch/s390/util/sym-handling.c b/tools/perf/arch/s390/util/sym-handling.c > new file mode 100644 > index 0000000..efe2a50 > --- /dev/null > +++ b/tools/perf/arch/s390/util/sym-handling.c > @@ -0,0 +1,49 @@ > +#include <stdio.h> > +#include <stdlib.h> > +#include <unistd.h> > +#include "symbol.h" > +#include "map.h" > +#include "util.h" > +#include "machine.h" > + > +int arch__fix_module_baseaddr(struct machine *machine, > + u64 *start, const char *name) > +{ > + char path[PATH_MAX]; > + char *module_name = strdup(name); > + int len = strlen(module_name); > + FILE *file; > + int err = 0; > + u64 text_start; > + char *line = NULL; > + size_t n; > + char *sep; > + > + module_name[len - 1] = '\0'; > + module_name += 1; > + snprintf(path, PATH_MAX, "%s/sys/module/%s/sections/.text", > + machine->root_dir, module_name); > + file = fopen(path, "r"); > + if (file == NULL) > + return -1; > + > + len = getline(&line, &n, file); > + if (len < 0) { > + err = -1; > + goto out; > + } > + line[--len] = '\0'; /* \n */ > + sep = strrchr(line, 'x'); > + if (sep == NULL) { > + err = -1; > + goto out; > + } > + hex2u64(sep + 1, &text_start); > + > + *start = text_start; > +out: > + free(line); > + fclose(file); > + free(module_name - 1); > + return err; > +} > diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c > index b177218..e5c2721 100644 > --- a/tools/perf/util/machine.c > +++ b/tools/perf/util/machine.c > @@ -1091,12 +1091,18 @@ static int machine__set_modules_path(struct machine *machine) > > return map_groups__set_modules_path_dir(&machine->kmaps, modules_path, 0); > } > +int __weak arch__fix_module_baseaddr(struct machine *machine __maybe_unused, > + u64 *start __maybe_unused, const char *name __maybe_unused) > +{ > + return 0; > +} > > static int machine__create_module(void *arg, const char *name, u64 start) > { > struct machine *machine = arg; > struct map *map; > > + arch__fix_module_baseaddr(machine, &start, name);
As the description says, I would change the function name to 'arch__fix_module_text_start';
> map = machine__findnew_module_map(machine, start, name); > if (map == NULL) > return -1; > diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h > index 41ac9cf..da7b6c0 100644 > --- a/tools/perf/util/machine.h > +++ b/tools/perf/util/machine.h > @@ -216,6 +216,8 @@ struct symbol *machine__find_kernel_function_by_name(struct machine *machine, > > struct map *machine__findnew_module_map(struct machine *machine, u64 start, > const char *filename); > +int arch__fix_module_baseaddr(struct machine *machine, u64 *start, > + const char *name); > > int __machine__load_kallsyms(struct machine *machine, const char *filename, > enum map_type type, bool no_kcore, symbol_filter_t filter); >
-- SongShan Gong
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