diff options
Diffstat (limited to 'tapsets.cxx')
| -rw-r--r-- | tapsets.cxx | 113 |
1 files changed, 57 insertions, 56 deletions
diff --git a/tapsets.cxx b/tapsets.cxx index eb66f2bc..78d47dc7 100644 --- a/tapsets.cxx +++ b/tapsets.cxx @@ -2278,55 +2278,11 @@ static int query_kernel_module (Dwfl_Module *, void **, const char *, 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 (sess.sym_kprobes_text_start != 0 && sess.sym_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) + if (addr >= sess.sym_kprobes_text_start && addr < sess.sym_kprobes_text_end) return true; } return false; @@ -2455,6 +2411,13 @@ dwarf_query::add_probe_point(const string& funcname, if (sess.verbose > 1) clog << endl; + if (module == TOK_KERNEL) + { + // PR 4224: adapt to relocatable kernel by subtracting the _stext address here. + reloc_addr = addr - sess.sym_stext; + reloc_section = "_stext"; // a deliberate eyesore + } + if (! bad) { probe = new dwarf_derived_probe(funcname, filename, line, @@ -2938,9 +2901,9 @@ query_module (Dwfl_Module *mod __attribute__ ((unused)), if (q->sess.verbose>2) clog << "focused on module '" << q->dw.module_name - << " = [" << hex << q->dw.module_start - << "-" << q->dw.module_end - << ", bias " << q->dw.module_bias << "]" << dec + << " = [0x" << hex << q->dw.module_start + << "-0x" << q->dw.module_end + << ", bias 0x" << q->dw.module_bias << "]" << dec << " file " << debug_filename << " ELF machine " << expect_machine << " (code " << elf_machine << ")" @@ -3495,11 +3458,9 @@ dwarf_derived_probe::dwarf_derived_probe(const string& funcname, maxactive_val (q.maxactive_val) { // Assert relocation invariants - if (module == TOK_KERNEL && section != "") - throw semantic_error ("relocation requested against kernel", q.base_loc->tok); - if (module != TOK_KERNEL && section == "") - throw semantic_error ("missing relocation base against module", q.base_loc->tok); - if (module != TOK_KERNEL && section != "" && dwfl_addr == addr) // addr should be an offset + if (section == "") + throw semantic_error ("missing relocation base against", q.base_loc->tok); + if (section != "" && dwfl_addr == addr) // addr should be an offset throw semantic_error ("inconsistent relocation address", q.base_loc->tok); // Make a target-variable-expanded copy of the probe body @@ -3734,9 +3695,9 @@ dwarf_derived_probe_group::emit_module_decls (systemtap_session& s) s.op->line() << " .return_p=1,"; if (p->has_maxactive) s.op->line() << " .maxactive_p=1,"; - if (p->module != TOK_KERNEL) // relocation info - s.op->line() << " .module=\"" << p->module << "\", .section=\"" << p->section << "\","; s.op->line() << " .address=0x" << hex << p->addr << dec << "UL,"; + s.op->line() << " .module=\"" << p->module << "\","; + s.op->line() << " .section=\"" << p->section << "\","; if (p->has_maxactive) s.op->line() << " .maxactive_val=" << p->maxactive_val << "UL,"; s.op->line() << " .pp=" << lex_cast_qstring (*p->sole_location()) << ","; @@ -3827,6 +3788,26 @@ dwarf_derived_probe_group::emit_module_exit (systemtap_session& s) } + +static Dwarf_Addr +lookup_symbol_address (Dwfl_Module *m, const char* wanted) +{ + int syments = dwfl_module_getsymtab(m); + assert(syments); + for (int i = 1; i < syments; ++i) + { + GElf_Sym sym; + const char *name = dwfl_module_getsym(m, i, &sym, NULL); + if (name != NULL && strcmp(name, wanted) == 0) + return sym.st_value; + } + + return 0; +} + + + + void dwarf_builder::build(systemtap_session & sess, probe * base, @@ -3852,6 +3833,26 @@ dwarf_builder::build(systemtap_session & sess, kern_dw->setup(true); } dw = kern_dw; + + + Dwfl_Module* km = 0; + dw->iterate_over_modules(&query_kernel_module, &km); + if (km) + { + sess.sym_kprobes_text_start = lookup_symbol_address (km, "__kprobes_text_start"); + sess.sym_kprobes_text_end = lookup_symbol_address (km, "__kprobes_text_end"); + sess.sym_stext = lookup_symbol_address (km, "_stext"); + + if (sess.verbose > 2) + { + clog << "control symbols:" + // abbreviate the names - they're for our debugging only anyway + << " kts: 0x" << hex << sess.sym_kprobes_text_start + << " kte: 0x" << sess.sym_kprobes_text_end + << " stext: 0x" << sess.sym_stext + << dec << endl; + } + } } else { |