--- /dev/null
+#include <linux/compiler.h>
+#include <elfutils/libdw.h>
+#include <elfutils/libdwfl.h>
+#include <inttypes.h>
+#include <errno.h>
+#include "debug.h"
+#include "unwind.h"
+#include "unwind-libdw.h"
+#include "machine.h"
+#include "thread.h"
+#include <linux/types.h>
+#include "event.h"
+#include "perf_regs.h"
+
+static char *debuginfo_path;
+
+static const Dwfl_Callbacks offline_callbacks = {
+ .find_debuginfo = dwfl_standard_find_debuginfo,
+ .debuginfo_path = &debuginfo_path,
+ .section_address = dwfl_offline_section_address,
+};
+
+static int __report_module(struct addr_location *al, u64 ip,
+ struct unwind_info *ui)
+{
+ Dwfl_Module *mod;
+ struct dso *dso = NULL;
+
+ thread__find_addr_location(ui->thread,
+ PERF_RECORD_MISC_USER,
+ MAP__FUNCTION, ip, al);
+
+ if (al->map)
+ dso = al->map->dso;
+
+ if (!dso)
+ return 0;
+
+ mod = dwfl_addrmodule(ui->dwfl, ip);
+ if (!mod)
+ mod = dwfl_report_elf(ui->dwfl, dso->short_name,
+ dso->long_name, -1, al->map->start,
+ false);
+
+ return mod && dwfl_addrmodule(ui->dwfl, ip) == mod ? 0 : -1;
+}
+
+static int report_module(u64 ip, struct unwind_info *ui)
+{
+ struct addr_location al;
+
+ return __report_module(&al, ip, ui);
+}
+
+static int entry(u64 ip, struct unwind_info *ui)
+
+{
+ struct unwind_entry e;
+ struct addr_location al;
+
+ if (__report_module(&al, ip, ui))
+ return -1;
+
+ e.ip = ip;
+ e.map = al.map;
+ e.sym = al.sym;
+
+ pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
+ al.sym ? al.sym->name : "''",
+ ip,
+ al.map ? al.map->map_ip(al.map, ip) : (u64) 0);
+
+ return ui->cb(&e, ui->arg);
+}
+
+static pid_t next_thread(Dwfl *dwfl, void *arg, void **thread_argp)
+{
+ /* We want only single thread to be processed. */
+ if (*thread_argp != NULL)
+ return 0;
+
+ *thread_argp = arg;
+ return dwfl_pid(dwfl);
+}
+
+static int access_dso_mem(struct unwind_info *ui, Dwarf_Addr addr,
+ Dwarf_Word *data)
+{
+ struct addr_location al;
+ ssize_t size;
+
+ thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER,
+ MAP__FUNCTION, addr, &al);
+ if (!al.map) {
+ pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
+ return -1;
+ }
+
+ if (!al.map->dso)
+ return -1;
+
+ size = dso__data_read_addr(al.map->dso, al.map, ui->machine,
+ addr, (u8 *) data, sizeof(*data));
+
+ return !(size == sizeof(*data));
+}
+
+static bool memory_read(Dwfl *dwfl __maybe_unused, Dwarf_Addr addr, Dwarf_Word *result,
+ void *arg)
+{
+ struct unwind_info *ui = arg;
+ struct stack_dump *stack = &ui->sample->user_stack;
+ u64 start, end;
+ int offset;
+ int ret;
+
+ ret = perf_reg_value(&start, &ui->sample->user_regs, PERF_REG_SP);
+ if (ret)
+ return false;
+
+ end = start + stack->size;
+
+ /* Check overflow. */
+ if (addr + sizeof(Dwarf_Word) < addr)
+ return false;
+
+ if (addr < start || addr + sizeof(Dwarf_Word) > end) {
+ ret = access_dso_mem(ui, addr, result);
+ if (ret) {
+ pr_debug("unwind: access_mem 0x%" PRIx64 " not inside range"
+ " 0x%" PRIx64 "-0x%" PRIx64 "\n",
+ addr, start, end);
+ return false;
+ }
+ return true;
+ }
+
+ offset = addr - start;
+ *result = *(Dwarf_Word *)&stack->data[offset];
+ pr_debug("unwind: access_mem addr 0x%" PRIx64 ", val %lx, offset %d\n",
+ addr, (unsigned long)*result, offset);
+ return true;
+}
+
+static const Dwfl_Thread_Callbacks callbacks = {
+ .next_thread = next_thread,
+ .memory_read = memory_read,
+ .set_initial_registers = libdw__arch_set_initial_registers,
+};
+
+static int
+frame_callback(Dwfl_Frame *state, void *arg)
+{
+ struct unwind_info *ui = arg;
+ Dwarf_Addr pc;
+
+ if (!dwfl_frame_pc(state, &pc, NULL)) {
+ pr_err("%s", dwfl_errmsg(-1));
+ return DWARF_CB_ABORT;
+ }
+
+ return entry(pc, ui) || !(--ui->max_stack) ?
+ DWARF_CB_ABORT : DWARF_CB_OK;
+}
+
+int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
+ struct thread *thread,
+ struct perf_sample *data,
+ int max_stack)
+{
+ struct unwind_info ui = {
+ .sample = data,
+ .thread = thread,
+ .machine = thread->mg->machine,
+ .cb = cb,
+ .arg = arg,
+ .max_stack = max_stack,
+ };
+ Dwarf_Word ip;
+ int err = -EINVAL;
+
+ if (!data->user_regs.regs)
+ return -EINVAL;
+
+ ui.dwfl = dwfl_begin(&offline_callbacks);
+ if (!ui.dwfl)
+ goto out;
+
+ err = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP);
+ if (err)
+ goto out;
+
+ err = report_module(ip, &ui);
+ if (err)
+ goto out;
+
+ if (!dwfl_attach_state(ui.dwfl, EM_NONE, thread->tid, &callbacks, &ui))
+ goto out;
+
+ err = dwfl_getthread_frames(ui.dwfl, thread->tid, frame_callback, &ui);
+
+ if (err && !ui.max_stack)
+ err = 0;
+
+ out:
+ if (err)
+ pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1));
+
+ dwfl_end(ui.dwfl);
+ return 0;
+}
Code Review / kvmfornfv.git / blobdiff