diff options
| -rw-r--r-- | gdb/ChangeLog | 10 | ||||
| -rw-r--r-- | gdb/fbsd-tdep.c | 153 | ||||
| -rw-r--r-- | gdb/fbsd-tdep.h | 11 |
3 files changed, 174 insertions, 0 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 2adc64e..ae7203a 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,5 +1,15 @@ 2019-03-12 John Baldwin <jhb@FreeBSD.org> + * fbsd-tdep.c (fbsd_pspace_data_handle): New variable. + (struct fbsd_pspace_data): New type. + (get_fbsd_pspace_data, fbsd_pspace_data_cleanup) + (fbsd_read_integer_by_name, fbsd_fetch_rtld_offsets) + (fbsd_get_tls_index, fbsd_get_thread_local_address): New function. + (_initialize_fbsd_tdep): Initialize 'fbsd_pspace_data_handle'. + * fbsd-tdep.c (fbsd_get_thread_local_address): New prototype. + +2019-03-12 John Baldwin <jhb@FreeBSD.org> + * gdbtypes.c (lookup_struct_elt): New function. (lookup_struct_elt_type): Reimplement via lookup_struct_elt. * gdbtypes.h (struct struct_elt): New type. diff --git a/gdb/fbsd-tdep.c b/gdb/fbsd-tdep.c index d971d3a..f068362 100644 --- a/gdb/fbsd-tdep.c +++ b/gdb/fbsd-tdep.c @@ -24,6 +24,7 @@ #include "regcache.h" #include "regset.h" #include "gdbthread.h" +#include "objfiles.h" #include "xml-syscall.h" #include <sys/socket.h> #include <arpa/inet.h> @@ -444,6 +445,41 @@ get_fbsd_gdbarch_data (struct gdbarch *gdbarch) gdbarch_data (gdbarch, fbsd_gdbarch_data_handle)); } +/* Per-program-space data for FreeBSD architectures. */ +static const struct program_space_data *fbsd_pspace_data_handle; + +struct fbsd_pspace_data +{ + /* Offsets in the runtime linker's 'Obj_Entry' structure. */ + LONGEST off_linkmap; + LONGEST off_tlsindex; + bool rtld_offsets_valid; +}; + +static struct fbsd_pspace_data * +get_fbsd_pspace_data (struct program_space *pspace) +{ + struct fbsd_pspace_data *data; + + data = ((struct fbsd_pspace_data *) + program_space_data (pspace, fbsd_pspace_data_handle)); + if (data == NULL) + { + data = XCNEW (struct fbsd_pspace_data); + set_program_space_data (pspace, fbsd_pspace_data_handle, data); + } + + return data; +} + +/* The cleanup callback for FreeBSD architecture per-program-space data. */ + +static void +fbsd_pspace_data_cleanup (struct program_space *pspace, void *data) +{ + xfree (data); +} + /* This is how we want PTIDs from core files to be printed. */ static const char * @@ -1932,6 +1968,121 @@ fbsd_get_syscall_number (struct gdbarch *gdbarch, thread_info *thread) internal_error (__FILE__, __LINE__, _("fbsd_get_sycall_number called")); } +/* Read an integer symbol value from the current target. */ + +static LONGEST +fbsd_read_integer_by_name (struct gdbarch *gdbarch, const char *name) +{ + bound_minimal_symbol ms = lookup_minimal_symbol (name, NULL, NULL); + if (ms.minsym == NULL) + error (_("Unable to resolve symbol '%s'"), name); + + gdb_byte buf[4]; + if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms), buf, sizeof buf) != 0) + error (_("Unable to read value of '%s'"), name); + + return extract_signed_integer (buf, sizeof buf, gdbarch_byte_order (gdbarch)); +} + +/* Lookup offsets of fields in the runtime linker's 'Obj_Entry' + structure needed to determine the TLS index of an object file. */ + +static void +fbsd_fetch_rtld_offsets (struct gdbarch *gdbarch, struct fbsd_pspace_data *data) +{ + TRY + { + /* Fetch offsets from debug symbols in rtld. */ + struct symbol *obj_entry_sym + = lookup_symbol_in_language ("Struct_Obj_Entry", NULL, STRUCT_DOMAIN, + language_c, NULL).symbol; + if (obj_entry_sym == NULL) + error (_("Unable to find Struct_Obj_Entry symbol")); + data->off_linkmap = lookup_struct_elt (SYMBOL_TYPE(obj_entry_sym), + "linkmap", 0).offset / 8; + data->off_tlsindex = lookup_struct_elt (SYMBOL_TYPE(obj_entry_sym), + "tlsindex", 0).offset / 8; + data->rtld_offsets_valid = true; + return; + } + CATCH (e, RETURN_MASK_ERROR) + { + data->off_linkmap = -1; + } + END_CATCH + + TRY + { + /* Fetch offsets from global variables in libthr. Note that + this does not work for single-threaded processes that are not + linked against libthr. */ + data->off_linkmap = fbsd_read_integer_by_name (gdbarch, + "_thread_off_linkmap"); + data->off_tlsindex = fbsd_read_integer_by_name (gdbarch, + "_thread_off_tlsindex"); + data->rtld_offsets_valid = true; + return; + } + CATCH (e, RETURN_MASK_ERROR) + { + data->off_linkmap = -1; + } + END_CATCH +} + +/* Helper function to read the TLS index of an object file associated + with a link map entry at LM_ADDR. */ + +static LONGEST +fbsd_get_tls_index (struct gdbarch *gdbarch, CORE_ADDR lm_addr) +{ + struct fbsd_pspace_data *data = get_fbsd_pspace_data (current_program_space); + + if (!data->rtld_offsets_valid) + fbsd_fetch_rtld_offsets (gdbarch, data); + + if (data->off_linkmap == -1) + throw_error (TLS_GENERIC_ERROR, + _("Cannot fetch runtime linker structure offsets")); + + /* Simulate container_of to convert from LM_ADDR to the Obj_Entry + pointer and then compute the offset of the tlsindex member. */ + CORE_ADDR tlsindex_addr = lm_addr - data->off_linkmap + data->off_tlsindex; + + gdb_byte buf[4]; + if (target_read_memory (tlsindex_addr, buf, sizeof buf) != 0) + throw_error (TLS_GENERIC_ERROR, + _("Cannot find thread-local variables on this target")); + + return extract_signed_integer (buf, sizeof buf, gdbarch_byte_order (gdbarch)); +} + +/* See fbsd-tdep.h. */ + +CORE_ADDR +fbsd_get_thread_local_address (struct gdbarch *gdbarch, CORE_ADDR dtv_addr, + CORE_ADDR lm_addr, CORE_ADDR offset) +{ + LONGEST tls_index = fbsd_get_tls_index (gdbarch, lm_addr); + + gdb_byte buf[gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT]; + if (target_read_memory (dtv_addr, buf, sizeof buf) != 0) + throw_error (TLS_GENERIC_ERROR, + _("Cannot find thread-local variables on this target")); + + const struct builtin_type *builtin = builtin_type (gdbarch); + CORE_ADDR addr = gdbarch_pointer_to_address (gdbarch, + builtin->builtin_data_ptr, buf); + + addr += (tls_index + 1) * TYPE_LENGTH (builtin->builtin_data_ptr); + if (target_read_memory (addr, buf, sizeof buf) != 0) + throw_error (TLS_GENERIC_ERROR, + _("Cannot find thread-local variables on this target")); + + addr = gdbarch_pointer_to_address (gdbarch, builtin->builtin_data_ptr, buf); + return addr + offset; +} + /* To be called from GDB_OSABI_FREEBSD handlers. */ void @@ -1957,4 +2108,6 @@ _initialize_fbsd_tdep (void) { fbsd_gdbarch_data_handle = gdbarch_data_register_post_init (init_fbsd_gdbarch_data); + fbsd_pspace_data_handle + = register_program_space_data_with_cleanup (NULL, fbsd_pspace_data_cleanup); } diff --git a/gdb/fbsd-tdep.h b/gdb/fbsd-tdep.h index efd7c2c..0e29508 100644 --- a/gdb/fbsd-tdep.h +++ b/gdb/fbsd-tdep.h @@ -60,4 +60,15 @@ extern void fbsd_info_proc_mappings_entry (int addr_bit, ULONGEST kve_start, int kve_flags, int kve_protection, const void *kve_path); +/* Helper function to fetch the address of a thread-local variable. + DTV_ADDR is the base address of the thread's dtv array. LM_ADDR is + the address of the link_map structure for the associated object + file. OFFSET is the offset of the variable in the object file's + thread-local variable block. */ + +extern CORE_ADDR fbsd_get_thread_local_address (struct gdbarch *gdbarch, + CORE_ADDR dtv_addr, + CORE_ADDR lm_addr, + CORE_ADDR offset); + #endif /* fbsd-tdep.h */ |