perf probe: Add basic module support

[mv-sheeva.git] / tools / perf / util / probe-finder.c

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index a274fd0c143eaa997e57ccdd3f34b006848f89dc..c20bd52833aae6efc30dde0c87b04111230e5d0a 100644 (file)
--- 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;
 }