From: Glenn Washburn Date: Thu, 1 Jun 2023 04:25:55 +0000 (-0500) Subject: gdb: Add gdbinfo command for printing the load address of the EFI application X-Git-Tag: grub-2.12-rc1~38 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c016a969d1eb59701face9ba14c19d67540f7037;p=thirdparty%2Fgrub.git gdb: Add gdbinfo command for printing the load address of the EFI application EFI firmware determines where to load the GRUB EFI at runtime, and so the addresses of debug symbols are not known ahead of time. There is a command defined in the gdb_grub script which will load the debug symbols at the appropriate addresses, if given the application load address for GRUB. So add a command named "gdbinfo" to allow the user to print this GDB command string with the application load address on-demand. For the outputted GDB command to have any effect when entered into a GDB session, GDB should have been started with the script as an argument to the -x option or sourced into an active GDB session before running the outputted command. Documentation for the gdbinfo command is also added. Co-developed-by: Peter Jones Signed-off-by: Peter Jones Signed-off-by: Glenn Washburn Reviewed-by: Daniel Kiper --- diff --git a/docs/grub.texi b/docs/grub.texi index 058b0eaaf..9b58886a9 100644 --- a/docs/grub.texi +++ b/docs/grub.texi @@ -4324,6 +4324,7 @@ you forget a command, you can run the command @command{help} * export:: Export an environment variable * false:: Do nothing, unsuccessfully * fwsetup:: Reboot into the firmware setup menu +* gdbinfo:: Provide info for debugging with GDB * gettext:: Translate a string * gptsync:: Fill an MBR based on GPT entries * halt:: Shut down your computer @@ -4856,6 +4857,18 @@ exit successfully if so. @end deffn +@node gdbinfo +@subsection gdbinfo + +@deffn Command gdbinfo +Output text to be used as a GDB command for a GDB session using the gdb_grub +script and attached to a running GRUB instance. The GDB command that is +output will tell GDB how to load debugging symbols to their proper runtime +address. Currently this is only available for EFI platforms. See the Debugging +in the developer documentation for more information. +@end deffn + + @node gettext @subsection gettext diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def index a8c0c4a52..e458aa665 100644 --- a/grub-core/Makefile.core.def +++ b/grub-core/Makefile.core.def @@ -211,6 +211,7 @@ kernel = { efi = disk/efi/efidisk.c; efi = kern/efi/efi.c; + efi = kern/efi/debug.c; efi = kern/efi/init.c; efi = kern/efi/mm.c; efi = term/efi/console.c; diff --git a/grub-core/kern/efi/debug.c b/grub-core/kern/efi/debug.c new file mode 100644 index 000000000..5d2ab1a36 --- /dev/null +++ b/grub-core/kern/efi/debug.c @@ -0,0 +1,38 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2022 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see . + */ +/* debug.c - aides for debugging the EFI application */ + +#include +#include +#include + +static grub_err_t +grub_cmd_gdbinfo (struct grub_command *cmd __attribute__ ((unused)), + int argc __attribute__ ((unused)), + char **args __attribute__ ((unused))) +{ + grub_efi_print_gdb_info (); + return 0; +} + +void +grub_efi_register_debug_commands (void) +{ + grub_register_command ("gdbinfo", grub_cmd_gdbinfo, 0, + N_("Print infomation useful for GDB debugging")); +} diff --git a/grub-core/kern/efi/efi.c b/grub-core/kern/efi/efi.c index f54fdcacd..a2afd8de9 100644 --- a/grub-core/kern/efi/efi.c +++ b/grub-core/kern/efi/efi.c @@ -320,7 +320,7 @@ grub_efi_get_variable (const char *var, const grub_guid_t *guid, /* Search the mods section from the PE32/PE32+ image. This code uses a PE32 header, but should work with PE32+ as well. */ grub_addr_t -grub_efi_modules_addr (void) +grub_efi_section_addr (const char *section_name) { grub_efi_loaded_image_t *image; struct grub_msdos_image_header *header; @@ -349,7 +349,7 @@ grub_efi_modules_addr (void) i < coff_header->num_sections; i++, section++) { - if (grub_strcmp (section->name, "mods") == 0) + if (grub_strcmp (section->name, section_name) == 0) break; } diff --git a/grub-core/kern/efi/init.c b/grub-core/kern/efi/init.c index 8a9c838c0..6fe1ff8c8 100644 --- a/grub-core/kern/efi/init.c +++ b/grub-core/kern/efi/init.c @@ -19,6 +19,7 @@ #include #include +#include #include #include #include @@ -104,7 +105,7 @@ grub_addr_t grub_modbase; void grub_efi_init (void) { - grub_modbase = grub_efi_modules_addr (); + grub_modbase = grub_efi_section_addr ("mods"); /* First of all, initialize the console so that GRUB can display messages. */ grub_console_init (); @@ -127,6 +128,8 @@ grub_efi_init (void) grub_efi_system_table->boot_services->set_watchdog_timer (0, 0, 0, NULL); grub_efidisk_init (); + + grub_efi_register_debug_commands (); } void (*grub_efi_net_config) (grub_efi_handle_t hnd, diff --git a/include/grub/efi/debug.h b/include/grub/efi/debug.h new file mode 100644 index 000000000..c2d2a03b0 --- /dev/null +++ b/include/grub/efi/debug.h @@ -0,0 +1,41 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2022 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see . + */ +/* debug.h - declare variables and functions for EFI debugging support */ + +#ifndef GRUB_EFI_DEBUG_HEADER +#define GRUB_EFI_DEBUG_HEADER 1 + +#include +#include + + +void grub_efi_register_debug_commands (void); + +static inline void +grub_efi_print_gdb_info (void) +{ + grub_addr_t text; + + text = grub_efi_section_addr (".text"); + if (!text) + return; + + grub_printf ("dynamic_load_symbols %p\n", (void *)text); +} + +#endif /* ! GRUB_EFI_DEBUG_HEADER */ diff --git a/include/grub/efi/efi.h b/include/grub/efi/efi.h index cd977cbbc..572f7135f 100644 --- a/include/grub/efi/efi.h +++ b/include/grub/efi/efi.h @@ -129,7 +129,7 @@ grub_err_t grub_arch_efi_linux_load_image_header(grub_file_t file, grub_err_t grub_arch_efi_linux_boot_image(grub_addr_t addr, grub_size_t size, char *args); -grub_addr_t grub_efi_modules_addr (void); +grub_addr_t grub_efi_section_addr (const char *section); void grub_efi_mm_init (void); void grub_efi_mm_fini (void);