From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Peter Jones <pjones@redhat.com>
Date: Thu, 4 Apr 2024 11:57:54 -0600
Subject: [PATCH] Make a "gdb" dprintf that tells us load addresses.

This makes a grub_dprintf() call during platform init and during module
loading that tells us the virtual addresses of the .text and .data
sections of grub-core/kernel.exec and any modules it loads.

Specifically, it displays them in the gdb "add-symbol-file" syntax, with
the presumption that there's a variable $grubdir that reflects the path
to any such binaries.

Signed-off-by: Peter Jones <pjones@redhat.com>
---
 grub-core/kern/dl.c       | 34 ++++++++++++++++++++++++++++++++++
 grub-core/kern/efi/init.c |  1 +
 2 files changed, 35 insertions(+)

diff --git a/grub-core/kern/dl.c b/grub-core/kern/dl.c
index 2a9ae9fc894..2eaef7150ed 100644
--- a/grub-core/kern/dl.c
+++ b/grub-core/kern/dl.c
@@ -690,6 +690,38 @@ grub_dl_relocate_symbols (grub_dl_t mod, void *ehdr)
   return GRUB_ERR_NONE;
 }
 
+static void
+grub_dl_print_gdb_info (grub_dl_t mod, Elf_Ehdr *e)
+{
+  void *text, *data = NULL;
+  long idx;
+
+  idx = grub_dl_find_section_index (e, ".text");
+  if (idx < 0)
+    return;
+
+  text = grub_dl_get_section_addr (mod, idx);
+  if (!text)
+    return;
+
+  idx = grub_dl_find_section_index (e, ".data");
+  if (idx >= 0)
+    data = grub_dl_get_section_addr (mod, idx);
+
+  if (data)
+    grub_qdprintf ("gdb", "add-symbol-file \\\n"
+		          "/usr/lib/debug/usr/lib/grub/%s-%s/%s.debug "
+			  "\\\n %p -s .data %p\n",
+		  GRUB_TARGET_CPU, GRUB_PLATFORM,
+		  mod->name, text, data);
+  else
+    grub_qdprintf ("gdb", "add-symbol-file \\\n"
+			   "/usr/lib/debug/usr/lib/grub/%s-%s/%s.debug "
+			   "\\\n%p\n",
+		  GRUB_TARGET_CPU, GRUB_PLATFORM,
+		  mod->name, text);
+}
+
 static grub_err_t
 grub_dl_set_mem_attrs (grub_dl_t mod, void *ehdr)
 {
@@ -833,6 +865,8 @@ grub_dl_load_core_noinit (void *addr, grub_size_t size)
   grub_dprintf ("modules", "module name: %s\n", mod->name);
   grub_dprintf ("modules", "init function: %p\n", mod->init);
 
+  grub_dl_print_gdb_info (mod, e);
+
   if (grub_dl_add (mod))
     {
       grub_dl_unload (mod);
diff --git a/grub-core/kern/efi/init.c b/grub-core/kern/efi/init.c
index dee3918fd35..d35d6974734 100644
--- a/grub-core/kern/efi/init.c
+++ b/grub-core/kern/efi/init.c
@@ -157,6 +157,7 @@ grub_efi_init (void)
   grub_efi_system_table->boot_services->set_watchdog_timer (0, 0, 0, NULL);
 
   grub_efi_env_init ();
+  grub_efi_print_gdb_info ();
   grub_efidisk_init ();
 
   grub_efi_register_debug_commands ();