From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Peter Jones <pjones@redhat.com>

Date: Thu, 25 Jun 2015 15:11:36 -0400

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       | 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 88d2077709e..9557254035e 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.

@@ -653,6 +670,37 @@ 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

@@ -712,6 +760,8 @@ 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 ae9885edb84..d6a2fb57789 100644

--- a/grub-core/kern/efi/efi.c

+++ b/grub-core/kern/efi/efi.c

@@ -296,7 +296,7 @@ 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;

@@ -321,7 +321,7 @@ 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 6d39bd3ad29..2d12e6188fd 100644

--- a/grub-core/kern/efi/init.c

+++ b/grub-core/kern/efi/init.c

@@ -115,10 +115,33 @@ 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 ();

@@ -142,6 +165,7 @@ 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 03f9a9d0118..2e0691454b1 100644

--- a/include/grub/efi/efi.h

+++ b/include/grub/efi/efi.h

@@ -138,7 +138,7 @@ grub_err_t grub_arch_efi_linux_check_image(struct linux_arch_kernel_header *lh);

 grub_err_t grub_arch_efi_linux_boot_image(grub_addr_t addr, char *args);

 #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);