Messages in this thread | | | Date | Thu, 19 Apr 2018 18:33:13 -0500 | From | Kim Phillips <> | Subject | Re: [PATCH] perf tools: set kernel end address properly |
| |
On Thu, 19 Apr 2018 11:54:24 +0900 Namhyung Kim <namhyung@kernel.org> wrote:
> On Wed, Apr 18, 2018 at 07:37:59PM -0500, Kim Phillips wrote: > > diff --git a/tools/perf/arch/arm64/util/sym-handling.c b/tools/perf/arch/arm64/util/sym-handling.c > > index 0051b1ee8450..5c4a2e208bbc 100644 > > --- a/tools/perf/arch/arm64/util/sym-handling.c > > +++ b/tools/perf/arch/arm64/util/sym-handling.c > > @@ -20,3 +20,16 @@ bool elf__needs_adjust_symbols(GElf_Ehdr ehdr) > > ehdr.e_type == ET_DYN; > > } > > #endif > > + > > +const char *arch__normalize_symbol_name(const char *name) > > +{ > > + /* > > + * arm64 kernels compensating for a CPU erratum can put up a > > + * module_emit_adrp_veneer in place of a module_emit_plt_entry > > + */ > > + if (name && strlen(name) >= 23 && > > + !strncmp(name, "module_emit_adrp_veneer", 23)) > > + return "module_emit_plt_entry"; > > + > > + return name; > > +} > > I don't know it's always preferable or just for the test. It it's the > latter it may be better to move it to the test code.
AFACT, the veneer is a moniker and doesn't technically exist, and shouldn't be being looked-up. Both chunks of this diff are needed to pass perf test 1: this chunk above is because in arch__normalize_symbol_name(), we squash the perf test 1's "<veneer> not in *kallsyms*" problem, and in the below chunk, we prevent it coming up when the test code iterates over the *vmlinux* symbols. I.e. we need to prevent the veneer from coming up in both kallsyms *and* vmlinux.
> > diff --git a/tools/perf/tests/vmlinux-kallsyms.c b/tools/perf/tests/vmlinux-kallsyms.c > > index 1e5adb65632a..07064e76947d 100644 > > --- a/tools/perf/tests/vmlinux-kallsyms.c > > +++ b/tools/perf/tests/vmlinux-kallsyms.c > > @@ -163,6 +163,29 @@ int test__vmlinux_matches_kallsyms(struct test *test __maybe_unused, int subtest > > > > continue; > > } > > + } else if (pair) { > > + s64 skew = mem_start - UM(pair->start); > > + struct map *kmap = map_groups__find(&kallsyms.kmaps, type, mem_start); > > + struct map *vmap = map_groups__find(&vmlinux.kmaps, type, mem_start); > > + > > + /* > > + * arm64 kernels compensating for a CPU erratum can put up a > > + * module_emit_adrp_veneer in place of a module_emit_plt_entry > > + */ > > + if (llabs(skew) < page_size) > > It seems that we needs to check it's the ARM64 at least. If it's a
OK.
> rare case we might need to add more paranoid checks.
It's certainly rare: Adding the authors of the veneer to cc for comments:
Will, Ard, how probable are veneer-style symbols such as the one introduced in commit a257e0257 "arm64/kernel: don't ban ADRP to work around Cortex-A53 erratum #843419" to happen again in the future?
I would have thought WARNing on within-a-pagesize would be OK, Namhyung. Are you suggesting checking instead for a hardcoded veneer symbol string?
Thanks,
Kim
> > + { > > + pr_debug("NO ERR FOR SKEW %ld: %#" PRIx64 ": diff start addr v: %s k: %#" PRIx64 " %s\n", > > + skew, mem_start, sym->name, UM(pair->start), pair->name); > > + continue; > > + } > > + > > + pr_debug("ERR : %#" PRIx64 ": diff start addr v: %s k: %#" PRIx64 " %s\n", > > + mem_start, sym->name, UM(pair->start), pair->name); > > + > > + if (kmap && vmap) { > > + pr_debug(" : map v: %s k: %s\n", > > + vmap->dso->short_name, kmap->dso->short_name); > > + } > > } else > > pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n", > > mem_start, sym->name);
| |