4.14-stable review patch. If anyone has any objections, please let me know.
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commit 4d99e4136580d178e3523281a820be17bf814bf8 upstream.
On x86_64 the PTI entry trampolines are not in the kernel map created by perf tools. That results in the addresses having no symbols and prevents annotation. It also causes Intel PT to have decoding errors at the trampoline addresses.
Workaround that by creating maps for the trampolines.
At present the kernel does not export information revealing where the trampolines are. Until that happens, the addresses are hardcoded.
Signed-off-by: Adrian Hunter adrian.hunter@intel.com Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Andi Kleen ak@linux.intel.com Cc: Andy Lutomirski luto@kernel.org Cc: Dave Hansen dave.hansen@linux.intel.com Cc: H. Peter Anvin hpa@zytor.com Cc: Jiri Olsa jolsa@redhat.com Cc: Joerg Roedel joro@8bytes.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Cc: x86@kernel.org Link: http://lkml.kernel.org/r/1526986485-6562-6-git-send-email-adrian.hunter@inte... Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/machine.c | 96 +++++++++++++++++++++++++++++++++++++++ tools/perf/util/machine.h | 3 ++ tools/perf/util/symbol.c | 12 +++-- 3 files changed, 106 insertions(+), 5 deletions(-)
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 78aa1c5f19ca..968fd0454e6b 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -818,6 +818,102 @@ static int machine__get_running_kernel_start(struct machine *machine, return 0; }
+/* Kernel-space maps for symbols that are outside the main kernel map and module maps */ +struct extra_kernel_map { + u64 start; + u64 end; + u64 pgoff; +}; + +static int machine__create_extra_kernel_map(struct machine *machine, + struct dso *kernel, + struct extra_kernel_map *xm) +{ + struct kmap *kmap; + struct map *map; + + map = map__new2(xm->start, kernel, MAP__FUNCTION); + if (!map) + return -1; + + map->end = xm->end; + map->pgoff = xm->pgoff; + + kmap = map__kmap(map); + + kmap->kmaps = &machine->kmaps; + + map_groups__insert(&machine->kmaps, map); + + pr_debug2("Added extra kernel map %" PRIx64 "-%" PRIx64 "\n", + map->start, map->end); + + map__put(map); + + return 0; +} + +static u64 find_entry_trampoline(struct dso *dso) +{ + /* Duplicates are removed so lookup all aliases */ + const char *syms[] = { + "_entry_trampoline", + "__entry_trampoline_start", + "entry_SYSCALL_64_trampoline", + }; + struct symbol *sym = dso__first_symbol(dso, MAP__FUNCTION); + unsigned int i; + + for (; sym; sym = dso__next_symbol(sym)) { + if (sym->binding != STB_GLOBAL) + continue; + for (i = 0; i < ARRAY_SIZE(syms); i++) { + if (!strcmp(sym->name, syms[i])) + return sym->start; + } + } + + return 0; +} + +/* + * These values can be used for kernels that do not have symbols for the entry + * trampolines in kallsyms. + */ +#define X86_64_CPU_ENTRY_AREA_PER_CPU 0xfffffe0000000000ULL +#define X86_64_CPU_ENTRY_AREA_SIZE 0x2c000 +#define X86_64_ENTRY_TRAMPOLINE 0x6000 + +/* Map x86_64 PTI entry trampolines */ +int machine__map_x86_64_entry_trampolines(struct machine *machine, + struct dso *kernel) +{ + u64 pgoff = find_entry_trampoline(kernel); + int nr_cpus_avail, cpu; + + if (!pgoff) + return 0; + + nr_cpus_avail = machine__nr_cpus_avail(machine); + + /* Add a 1 page map for each CPU's entry trampoline */ + for (cpu = 0; cpu < nr_cpus_avail; cpu++) { + u64 va = X86_64_CPU_ENTRY_AREA_PER_CPU + + cpu * X86_64_CPU_ENTRY_AREA_SIZE + + X86_64_ENTRY_TRAMPOLINE; + struct extra_kernel_map xm = { + .start = va, + .end = va + page_size, + .pgoff = pgoff, + }; + + if (machine__create_extra_kernel_map(machine, kernel, &xm) < 0) + return -1; + } + + return 0; +} + int __machine__create_kernel_maps(struct machine *machine, struct dso *kernel) { int type; diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h index 245743d9ce63..13041b036a5b 100644 --- a/tools/perf/util/machine.h +++ b/tools/perf/util/machine.h @@ -266,4 +266,7 @@ int machine__set_current_tid(struct machine *machine, int cpu, pid_t pid, */ char *machine__resolve_kernel_addr(void *vmachine, unsigned long long *addrp, char **modp);
+int machine__map_x86_64_entry_trampolines(struct machine *machine, + struct dso *kernel); + #endif /* __PERF_MACHINE_H */ diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index ec40e47aa198..3936f69f385c 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -1513,20 +1513,22 @@ int dso__load(struct dso *dso, struct map *map) goto out; }
+ if (map->groups && map->groups->machine) + machine = map->groups->machine; + else + machine = NULL; + if (dso->kernel) { if (dso->kernel == DSO_TYPE_KERNEL) ret = dso__load_kernel_sym(dso, map); else if (dso->kernel == DSO_TYPE_GUEST_KERNEL) ret = dso__load_guest_kernel_sym(dso, map);
+ if (machine__is(machine, "x86_64")) + machine__map_x86_64_entry_trampolines(machine, dso); goto out; }
- if (map->groups && map->groups->machine) - machine = map->groups->machine; - else - machine = NULL; - dso->adjust_symbols = 0;
if (perfmap) {