diff options
Diffstat (limited to 'tapsets.cxx')
| -rw-r--r-- | tapsets.cxx | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/tapsets.cxx b/tapsets.cxx index 199f71a0..d2d4b9c2 100644 --- a/tapsets.cxx +++ b/tapsets.cxx @@ -2285,6 +2285,68 @@ target_variable_flavour_calculating_visitor::visit_target_symbol (target_symbol } +// Forward declaration. +static int query_kernel_module (Dwfl_Module *, void **, const char *, + Dwarf_Addr, void *); + + +static bool +in_kprobes_function(systemtap_session& sess, Dwarf_Addr addr) +{ + if (! sess.kprobes_text_initialized) + { + // Only attempt kprobes_text_start/kprobes_text_end + // initialization once + sess.kprobes_text_initialized = true; + + dwflpp *kernel_dw = new dwflpp(sess); + assert(kernel_dw); + kernel_dw->setup(true); + + Dwfl_Module *m = NULL; + kernel_dw->iterate_over_modules(&query_kernel_module, &m); + assert(m); + kernel_dw->focus_on_module(m); + + // Look through the symbol table for "__kprobes_text_{start,end}" + int syments = dwfl_module_getsymtab(kernel_dw->module); + assert(syments); + for (int i = 1; i < syments; ++i) + { + GElf_Sym sym; + const char *name = dwfl_module_getsym(kernel_dw->module, i, + &sym, NULL); + + // Look for a symbol that starts with "__kprobes_text_" + if (name != NULL + && strncmp(name, "__kprobes_text_", 15) == 0) + { + // Match either "__kprobes_text_start" or "__kprobes_text_end" + if (strcmp(name, "__kprobes_text_start") == 0) + sess.kprobes_text_start = sym.st_value; + else if (strcmp(name, "__kprobes_text_end") == 0) + sess.kprobes_text_end = sym.st_value; + + // If we've got both values, quit processing symbols. + if (sess.kprobes_text_start != 0 && sess.kprobes_text_end != 0) + i = syments; + } + } + + if (kernel_dw) + delete kernel_dw; + } + + if (sess.kprobes_text_start != 0 && sess.kprobes_text_end != 0) + { + // If the probe point address is anywhere in the __kprobes + // address range, we can't use this probe point. + if (addr >= sess.kprobes_text_start && addr < sess.kprobes_text_end) + return true; + } + return false; +} + bool dwarf_query::blacklisted_p(string const & funcname, @@ -2351,6 +2413,15 @@ dwarf_query::blacklisted_p(string const & funcname, } } + // Check for function marked '__kprobes'. + if (in_kprobes_function(sess, addr)) + { + if (sess.verbose>1) + clog << "skipping function '" << funcname << "' base 0x" + << hex << addr << dec << " is a function marked '__kprobes'\n"; + return true; + } + // Check probe point against blacklist. XXX: This has to be // properly generalized, perhaps via a table populated from script // files. A "noprobe kernel.function("...")" construct might do @@ -2826,6 +2897,24 @@ query_kernel_exists (Dwfl_Module *mod __attribute__ ((unused)), static int +query_kernel_module (Dwfl_Module *mod, + void **userdata __attribute__ ((unused)), + const char *name, + Dwarf_Addr base __attribute__ ((unused)), + void *arg) +{ + if (TOK_KERNEL == name) + { + Dwfl_Module **m = (Dwfl_Module **)arg; + + *m = mod; + return DWARF_CB_ABORT; + } + return DWARF_CB_OK; +} + + +static int query_module (Dwfl_Module *mod __attribute__ ((unused)), void **userdata __attribute__ ((unused)), const char *name, Dwarf_Addr base, |