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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Peter Jones <pjones@redhat.com>
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Date: Thu, 25 Jun 2015 15:11:36 -0400
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Subject: [PATCH] Make a "gdb" dprintf that tells us load addresses.
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This makes a grub_dprintf() call during platform init and during module
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loading that tells us the virtual addresses of the .text and .data
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sections of grub-core/kernel.exec and any modules it loads.
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Specifically, it displays them in the gdb "add-symbol-file" syntax, with
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the presumption that there's a variable $grubdir that reflects the path
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to any such binaries.
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Signed-off-by: Peter Jones <pjones@redhat.com>
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---
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 grub-core/kern/dl.c       | 50 +++++++++++++++++++++++++++++++++++++++++++++++
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 grub-core/kern/efi/efi.c  |  4 ++--
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 grub-core/kern/efi/init.c | 26 +++++++++++++++++++++++-
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 include/grub/efi/efi.h    |  2 +-
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 4 files changed, 78 insertions(+), 4 deletions(-)
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diff --git a/grub-core/kern/dl.c b/grub-core/kern/dl.c
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index 5028d157c46..eb8b969cded 100644
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--- a/grub-core/kern/dl.c
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+++ b/grub-core/kern/dl.c
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@@ -501,6 +501,23 @@ grub_dl_find_section (Elf_Ehdr *e, const char *name)
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       return s;
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   return NULL;
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 }
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+static long
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+grub_dl_find_section_index (Elf_Ehdr *e, const char *name)
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+{
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+  Elf_Shdr *s;
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+  const char *str;
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+  unsigned i;
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+
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+  s = (Elf_Shdr *) ((char *) e + e->e_shoff + e->e_shstrndx * e->e_shentsize);
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+  str = (char *) e + s->sh_offset;
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+
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+  for (i = 0, s = (Elf_Shdr *) ((char *) e + e->e_shoff);
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+       i < e->e_shnum;
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+       i++, s = (Elf_Shdr *) ((char *) s + e->e_shentsize))
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+    if (grub_strcmp (str + s->sh_name, name) == 0)
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+      return (long)i;
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+  return -1;
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+}
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 /* Me, Vladimir Serbinenko, hereby I add this module check as per new
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    GNU module policy. Note that this license check is informative only.
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@@ -644,6 +661,37 @@ grub_dl_relocate_symbols (grub_dl_t mod, void *ehdr)
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   return GRUB_ERR_NONE;
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 }
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+static void
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+grub_dl_print_gdb_info (grub_dl_t mod, Elf_Ehdr *e)
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+{
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+  void *text, *data = NULL;
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+  long idx;
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+
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+  idx = grub_dl_find_section_index (e, ".text");
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+  if (idx < 0)
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+    return;
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+
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+  text = grub_dl_get_section_addr (mod, idx);
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+  if (!text)
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+    return;
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+
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+  idx = grub_dl_find_section_index (e, ".data");
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+  if (idx >= 0)
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+    data = grub_dl_get_section_addr (mod, idx);
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+
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+  if (data)
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+    grub_qdprintf ("gdb", "add-symbol-file \\\n"
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+		          "/usr/lib/debug/usr/lib/grub/%s-%s/%s.debug "
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+			  "\\\n %p -s .data %p\n",
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+		  GRUB_TARGET_CPU, GRUB_PLATFORM,
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+		  mod->name, text, data);
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+  else
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+    grub_qdprintf ("gdb", "add-symbol-file \\\n"
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+			   "/usr/lib/debug/usr/lib/grub/%s-%s/%s.debug "
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+			   "\\\n%p\n",
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+		  GRUB_TARGET_CPU, GRUB_PLATFORM,
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+		  mod->name, text);
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+}
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 /* Load a module from core memory.  */
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 grub_dl_t
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@@ -703,6 +751,8 @@ grub_dl_load_core_noinit (void *addr, grub_size_t size)
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   grub_dprintf ("modules", "module name: %s\n", mod->name);
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   grub_dprintf ("modules", "init function: %p\n", mod->init);
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+  grub_dl_print_gdb_info (mod, e);
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+
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   if (grub_dl_add (mod))
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     {
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       grub_dl_unload (mod);
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diff --git a/grub-core/kern/efi/efi.c b/grub-core/kern/efi/efi.c
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index bcae7f4699d..a2a732ffc0d 100644
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--- a/grub-core/kern/efi/efi.c
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+++ b/grub-core/kern/efi/efi.c
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@@ -283,7 +283,7 @@ grub_efi_get_variable (const char *var, const grub_efi_guid_t *guid,
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 /* Search the mods section from the PE32/PE32+ image. This code uses
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    a PE32 header, but should work with PE32+ as well.  */
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 grub_addr_t
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-grub_efi_modules_addr (void)
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+grub_efi_section_addr (const char *section_name)
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 {
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   grub_efi_loaded_image_t *image;
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   struct grub_pe32_header *header;
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@@ -308,7 +308,7 @@ grub_efi_modules_addr (void)
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        i < coff_header->num_sections;
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        i++, section++)
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     {
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-      if (grub_strcmp (section->name, "mods") == 0)
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+      if (grub_strcmp (section->name, section_name) == 0)
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 	break;
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     }
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diff --git a/grub-core/kern/efi/init.c b/grub-core/kern/efi/init.c
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index 71d2279a0c1..e6183a4c44d 100644
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--- a/grub-core/kern/efi/init.c
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+++ b/grub-core/kern/efi/init.c
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@@ -59,10 +59,33 @@ grub_efi_env_init (void)
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   grub_free (envblk_s.buf);
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 }
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+static void
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+grub_efi_print_gdb_info (void)
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+{
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+  grub_addr_t text;
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+  grub_addr_t data;
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+
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+  text = grub_efi_section_addr (".text");
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+  if (!text)
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+    return;
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+
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+  data = grub_efi_section_addr (".data");
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+  if (data)
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+    grub_qdprintf ("gdb",
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+		  "add-symbol-file /usr/lib/debug/usr/lib/grub/%s-%s/"
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+		  "kernel.exec %p -s .data %p\n",
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+		  GRUB_TARGET_CPU, GRUB_PLATFORM, (void *)text, (void *)data);
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+  else
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+    grub_qdprintf ("gdb",
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+		  "add-symbol-file /usr/lib/debug/usr/lib/grub/%s-%s/"
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+		  "kernel.exec %p\n",
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+		  GRUB_TARGET_CPU, GRUB_PLATFORM, (void *)text);
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+}
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+
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 void
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 grub_efi_init (void)
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 {
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-  grub_modbase = grub_efi_modules_addr ();
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+  grub_modbase = grub_efi_section_addr ("mods");
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   /* First of all, initialize the console so that GRUB can display
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      messages.  */
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   grub_console_init ();
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@@ -74,6 +97,7 @@ grub_efi_init (void)
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 	      0, 0, 0, NULL);
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   grub_efi_env_init ();
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+  grub_efi_print_gdb_info ();
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   grub_efidisk_init ();
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 }
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diff --git a/include/grub/efi/efi.h b/include/grub/efi/efi.h
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index 09a18e56302..570a69361a5 100644
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--- a/include/grub/efi/efi.h
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+++ b/include/grub/efi/efi.h
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@@ -132,7 +132,7 @@ grub_err_t grub_armxx_efi_linux_check_image(struct linux_armxx_kernel_header *lh
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 grub_err_t grub_armxx_efi_linux_boot_image(grub_addr_t addr, char *args);
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 #endif
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-grub_addr_t grub_efi_modules_addr (void);
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+grub_addr_t grub_efi_section_addr (const char *section);
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 void grub_efi_mm_init (void);
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 void grub_efi_mm_fini (void);