1 files changed, 126 insertions, 16 deletions

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index a274fd0c143e..c20bd52833aa 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -116,6 +116,101 @@ static void line_list__free(struct list_head *head)
         }
 }
 
+/* Dwarf FL wrappers */
+
+static int __linux_kernel_find_elf(Dwfl_Module *mod,
+                                   void **userdata,
+                                   const char *module_name,
+                                   Dwarf_Addr base,
+                                   char **file_name, Elf **elfp)
+{
+        int fd;
+        const char *path = kernel_get_module_path(module_name);
+
+        if (path) {
+                fd = open(path, O_RDONLY);
+                if (fd >= 0) {
+                        *file_name = strdup(path);
+                        return fd;
+                }
+        }
+        /* If failed, try to call standard method */
+        return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
+                                          file_name, elfp);
+}
+
+static char *debuginfo_path;    /* Currently dummy */
+
+static const Dwfl_Callbacks offline_callbacks = {
+        .find_debuginfo = dwfl_standard_find_debuginfo,
+        .debuginfo_path = &debuginfo_path,
+
+        .section_address = dwfl_offline_section_address,
+
+        /* We use this table for core files too.  */
+        .find_elf = dwfl_build_id_find_elf,
+};
+
+static const Dwfl_Callbacks kernel_callbacks = {
+        .find_debuginfo = dwfl_standard_find_debuginfo,
+        .debuginfo_path = &debuginfo_path,
+
+        .find_elf = __linux_kernel_find_elf,
+        .section_address = dwfl_linux_kernel_module_section_address,
+};
+
+/* Get a Dwarf from offline image */
+static Dwarf *dwfl_init_offline_dwarf(int fd, Dwfl **dwflp, Dwarf_Addr *bias)
+{
+        Dwfl_Module *mod;
+        Dwarf *dbg = NULL;
+
+        if (!dwflp)
+                return NULL;
+
+        *dwflp = dwfl_begin(&offline_callbacks);
+        if (!*dwflp)
+                return NULL;
+
+        mod = dwfl_report_offline(*dwflp, "", "", fd);
+        if (!mod)
+                goto error;
+
+        dbg = dwfl_module_getdwarf(mod, bias);
+        if (!dbg) {
+error:
+                dwfl_end(*dwflp);
+                *dwflp = NULL;
+        }
+        return dbg;
+}
+
+/* Get a Dwarf from live kernel image */
+static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr, Dwfl **dwflp,
+                                          Dwarf_Addr *bias)
+{
+        Dwarf *dbg;
+
+        if (!dwflp)
+                return NULL;
+
+        *dwflp = dwfl_begin(&kernel_callbacks);
+        if (!*dwflp)
+                return NULL;
+
+        /* Load the kernel dwarves: Don't care the result here */
+        dwfl_linux_kernel_report_kernel(*dwflp);
+        dwfl_linux_kernel_report_modules(*dwflp);
+
+        dbg = dwfl_addrdwarf(*dwflp, addr, bias);
+        /* Here, check whether we could get a real dwarf */
+        if (!dbg) {
+                dwfl_end(*dwflp);
+                *dwflp = NULL;
+        }
+        return dbg;
+}
+
 /* Dwarf wrappers */
 
 /* Find the realpath of the target file. */
@@ -1177,10 +1272,12 @@ static int find_probes(int fd, struct probe_finder *pf)
         Dwarf_Off off, noff;
         size_t cuhl;
         Dwarf_Die *diep;
-        Dwarf *dbg;
+        Dwarf *dbg = NULL;
+        Dwfl *dwfl;
+        Dwarf_Addr bias;        /* Currently ignored */
         int ret = 0;
 
-        dbg = dwarf_begin(fd, DWARF_C_READ);
+        dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
         if (!dbg) {
                 pr_warning("No dwarf info found in the vmlinux - "
                         "please rebuild with CONFIG_DEBUG_INFO=y.\n");
@@ -1221,7 +1318,8 @@ static int find_probes(int fd, struct probe_finder *pf)
                 off = noff;
         }
         line_list__free(&pf->lcache);
-        dwarf_end(dbg);
+        if (dwfl)
+                dwfl_end(dwfl);
 
         return ret;
 }
@@ -1412,23 +1510,31 @@ int find_available_vars_at(int fd, struct perf_probe_event *pev,
 }
 
 /* Reverse search */
-int find_perf_probe_point(int fd, unsigned long addr,
-                          struct perf_probe_point *ppt)
+int find_perf_probe_point(unsigned long addr, struct perf_probe_point *ppt)
 {
         Dwarf_Die cudie, spdie, indie;
-        Dwarf *dbg;
+        Dwarf *dbg = NULL;
+        Dwfl *dwfl = NULL;
         Dwarf_Line *line;
-        Dwarf_Addr laddr, eaddr;
+        Dwarf_Addr laddr, eaddr, bias = 0;
         const char *tmp;
         int lineno, ret = 0;
         bool found = false;
 
-        dbg = dwarf_begin(fd, DWARF_C_READ);
-        if (!dbg)
-                return -EBADF;
+        /* Open the live linux kernel */
+        dbg = dwfl_init_live_kernel_dwarf(addr, &dwfl, &bias);
+        if (!dbg) {
+                pr_warning("No dwarf info found in the vmlinux - "
+                        "please rebuild with CONFIG_DEBUG_INFO=y.\n");
+                ret = -EINVAL;
+                goto end;
+        }
 
+        /* Adjust address with bias */
+        addr += bias;
         /* Find cu die */
-        if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr, &cudie)) {
+        if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr - bias, &cudie)) {
+                pr_warning("No CU DIE is found at %lx\n", addr);
                 ret = -EINVAL;
                 goto end;
         }
@@ -1491,7 +1597,8 @@ found:
         }
 
 end:
-        dwarf_end(dbg);
+        if (dwfl)
+                dwfl_end(dwfl);
         if (ret >= 0)
                 ret = found ? 1 : 0;
         return ret;
@@ -1624,6 +1731,8 @@ static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
         struct line_finder *lf = param->data;
         struct line_range *lr = lf->lr;
 
+        pr_debug("find (%lx) %s\n", dwarf_dieoffset(sp_die),
+                 dwarf_diename(sp_die));
         if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
             die_compare_name(sp_die, lr->function)) {
                 lf->fname = dwarf_decl_file(sp_die);
@@ -1667,10 +1776,12 @@ int find_line_range(int fd, struct line_range *lr)
         Dwarf_Off off = 0, noff;
         size_t cuhl;
         Dwarf_Die *diep;
-        Dwarf *dbg;
+        Dwarf *dbg = NULL;
+        Dwfl *dwfl;
+        Dwarf_Addr bias;        /* Currently ignored */
         const char *comp_dir;
 
-        dbg = dwarf_begin(fd, DWARF_C_READ);
+        dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
         if (!dbg) {
                 pr_warning("No dwarf info found in the vmlinux - "
                         "please rebuild with CONFIG_DEBUG_INFO=y.\n");
@@ -1716,8 +1827,7 @@ int find_line_range(int fd, struct line_range *lr)
         }
 
         pr_debug("path: %s\n", lr->path);
-        dwarf_end(dbg);
-
+        dwfl_end(dwfl);
         return (ret < 0) ? ret : lf.found;
 }