grub2/0215-Make-a-gdb-dprintf-that-tells-us-load-addresses.patch

From 2c0e3b593751a7f96c66899ca4a0ac75fc10fb12 Mon Sep 17 00:00:00 2001
From: Peter Jones <pjones@redhat.com>
Date: Thu, 25 Jun 2015 15:11:36 -0400
Subject: [PATCH 215/215] 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       | 50 +++++++++++++++++++++++++++++++++++++++++++++++
 grub-core/kern/efi/efi.c  |  4 ++--
 grub-core/kern/efi/init.c | 26 +++++++++++++++++++++++-
 include/grub/efi/efi.h    |  2 +-
 4 files changed, 78 insertions(+), 4 deletions(-)

diff --git a/grub-core/kern/dl.c b/grub-core/kern/dl.c
index 5028d157c46..eb8b969cded 100644
--- a/grub-core/kern/dl.c
+++ b/grub-core/kern/dl.c
@@ -501,6 +501,23 @@ grub_dl_find_section (Elf_Ehdr *e, const char *name)
       return s;
   return NULL;
 }
+static long
+grub_dl_find_section_index (Elf_Ehdr *e, const char *name)
+{
+  Elf_Shdr *s;
+  const char *str;
+  unsigned i;
+
+  s = (Elf_Shdr *) ((char *) e + e->e_shoff + e->e_shstrndx * e->e_shentsize);
+  str = (char *) e + s->sh_offset;
+
+  for (i = 0, s = (Elf_Shdr *) ((char *) e + e->e_shoff);
+       i < e->e_shnum;
+       i++, s = (Elf_Shdr *) ((char *) s + e->e_shentsize))
+    if (grub_strcmp (str + s->sh_name, name) == 0)
+      return (long)i;
+  return -1;
+}
 
 /* Me, Vladimir Serbinenko, hereby I add this module check as per new
    GNU module policy. Note that this license check is informative only.
@@ -644,6 +661,37 @@ 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);
+}
 
 /* Load a module from core memory.  */
 grub_dl_t
@@ -703,6 +751,8 @@ 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/efi.c b/grub-core/kern/efi/efi.c
index 91f75fdb89a..621251242e1 100644
--- a/grub-core/kern/efi/efi.c
+++ b/grub-core/kern/efi/efi.c
@@ -274,7 +274,7 @@ grub_efi_get_variable (const char *var, const grub_efi_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_pe32_header *header;
@@ -299,7 +299,7 @@ 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 f7782b6e114..79243b364a1 100644
--- a/grub-core/kern/efi/init.c
+++ b/grub-core/kern/efi/init.c
@@ -59,10 +59,33 @@ grub_efi_env_init (void)
   grub_free (envblk_s.buf);
 }
 
+static void
+grub_efi_print_gdb_info (void)
+{
+  grub_addr_t text;
+  grub_addr_t data;
+
+  text = grub_efi_section_addr (".text");
+  if (!text)
+    return;
+
+  data = grub_efi_section_addr (".data");
+  if (data)
+    grub_qdprintf ("gdb",
+		  "add-symbol-file /usr/lib/debug/usr/lib/grub/%s-%s/"
+		  "kernel.exec %p -s .data %p\n",
+		  GRUB_TARGET_CPU, GRUB_PLATFORM, (void *)text, (void *)data);
+  else
+    grub_qdprintf ("gdb",
+		  "add-symbol-file /usr/lib/debug/usr/lib/grub/%s-%s/"
+		  "kernel.exec %p\n",
+		  GRUB_TARGET_CPU, GRUB_PLATFORM, (void *)text);
+}
+
 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 ();
@@ -74,6 +97,7 @@ grub_efi_init (void)
 	      0, 0, 0, NULL);
 
   grub_efi_env_init ();
+  grub_efi_print_gdb_info ();
   grub_efidisk_init ();
 }
 
diff --git a/include/grub/efi/efi.h b/include/grub/efi/efi.h
index 68326d96f5a..6702b312040 100644
--- a/include/grub/efi/efi.h
+++ b/include/grub/efi/efi.h
@@ -126,7 +126,7 @@ extern void (*EXPORT_VAR(grub_efi_net_config)) (grub_efi_handle_t hnd,
 void *EXPORT_FUNC(grub_efi_get_firmware_fdt)(void);
 #endif
 
-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);
-- 
2.15.0