[PATCH] Use common linker script for all i386-pc systems

[Pavel Roskin]

This allows us to remove checks for the linker symbols for the beginning
and the end of the .bss section.  Instead, we use the names from the
linker script.  Another benefit is a better unification of the build
system.

ChangeLog:
        * aclocal.m4: Remove grub_CHECK_BSS_START_SYMBOL and
        grub_CHECK_END_SYMBOL.
        * configure.ac: Don't call grub_CHECK_BSS_START_SYMBOL and
        grub_CHECK_END_SYMBOL.  Check for ${target_cpu}-${platform}.lds
        as the linker script.
        * conf/i386-pc-cygwin-img-ld.sc: Rename to ...
        * conf/i386-pc.lds: ... this.
        * kern/i386/pc/startup.S: Use __bss_start__ and __bss_end__
        instead of BSS_START_SYMBOL and END_SYMBOL.
---
 aclocal.m4                    |   77 -----------------------------------------
 conf/i386-pc-cygwin-img-ld.sc |   53 ----------------------------
 conf/i386-pc.lds              |   53 ++++++++++++++++++++++++++++
 configure.ac                  |   10 ++---
 kern/i386/pc/startup.S        |    8 ++--
 5 files changed, 60 insertions(+), 141 deletions(-)
 delete mode 100644 conf/i386-pc-cygwin-img-ld.sc
 create mode 100644 conf/i386-pc.lds

diff --git a/aclocal.m4 b/aclocal.m4
index 779df3d..9a073b5 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -224,83 +224,6 @@ fi
 AC_MSG_RESULT([$grub_cv_i386_asm_absolute_without_asterisk])])
 
 
-dnl Check what symbol is defined as a bss start symbol.
-dnl Written by Michael Hohmoth and Yoshinori K. Okuji.
-AC_DEFUN(grub_CHECK_BSS_START_SYMBOL,
-[AC_REQUIRE([AC_PROG_CC])
-AC_MSG_CHECKING([if __bss_start is defined by the compiler])
-AC_CACHE_VAL(grub_cv_check_uscore_uscore_bss_start_symbol,
-[AC_LINK_IFELSE([AC_LANG_PROGRAM([[]],
-               [[asm ("incl __bss_start")]])],
-               [grub_cv_check_uscore_uscore_bss_start_symbol=yes],
-               [grub_cv_check_uscore_uscore_bss_start_symbol=no])])
-
-AC_MSG_RESULT([$grub_cv_check_uscore_uscore_bss_start_symbol])
-
-AC_MSG_CHECKING([if edata is defined by the compiler])
-AC_CACHE_VAL(grub_cv_check_edata_symbol,
-[AC_LINK_IFELSE([AC_LANG_PROGRAM([[]],
-               [[asm ("incl edata")]])],
-               [grub_cv_check_edata_symbol=yes],
-               [grub_cv_check_edata_symbol=no])])
-
-AC_MSG_RESULT([$grub_cv_check_edata_symbol])
-
-AC_MSG_CHECKING([if _edata is defined by the compiler])
-AC_CACHE_VAL(grub_cv_check_uscore_edata_symbol,
-[AC_LINK_IFELSE([AC_LANG_PROGRAM([[]],
-               [[asm ("incl _edata")]])],
-               [grub_cv_check_uscore_edata_symbol=yes],
-               [grub_cv_check_uscore_edata_symbol=no])])
-
-AC_MSG_RESULT([$grub_cv_check_uscore_edata_symbol])
-
-AH_TEMPLATE([BSS_START_SYMBOL], [Define it to one of __bss_start, edata and 
_edata])
-
-if test "x$grub_cv_check_uscore_uscore_bss_start_symbol" = xyes; then
-  AC_DEFINE([BSS_START_SYMBOL], [__bss_start])
-elif test "x$grub_cv_check_edata_symbol" = xyes; then
-  AC_DEFINE([BSS_START_SYMBOL], [edata])
-elif test "x$grub_cv_check_uscore_edata_symbol" = xyes; then
-  AC_DEFINE([BSS_START_SYMBOL], [_edata])
-else
-  AC_MSG_ERROR([none of __bss_start, edata or _edata is defined])
-fi
-])
-
-dnl Check what symbol is defined as an end symbol.
-dnl Written by Yoshinori K. Okuji.
-AC_DEFUN(grub_CHECK_END_SYMBOL,
-[AC_REQUIRE([AC_PROG_CC])
-AC_MSG_CHECKING([if end is defined by the compiler])
-AC_CACHE_VAL(grub_cv_check_end_symbol,
-[AC_LINK_IFELSE([AC_LANG_PROGRAM([[]],
-               [[asm ("incl end")]])],
-               [grub_cv_check_end_symbol=yes],
-               [grub_cv_check_end_symbol=no])])
-
-AC_MSG_RESULT([$grub_cv_check_end_symbol])
-
-AC_MSG_CHECKING([if _end is defined by the compiler])
-AC_CACHE_VAL(grub_cv_check_uscore_end_symbol,
-[AC_LINK_IFELSE([AC_LANG_PROGRAM([[]],
-               [[asm ("incl _end")]])],
-               [grub_cv_check_uscore_end_symbol=yes],
-               [grub_cv_check_uscore_end_symbol=no])])
-
-AC_MSG_RESULT([$grub_cv_check_uscore_end_symbol])
-
-AH_TEMPLATE([END_SYMBOL], [Define it to either end or _end])
-
-if test "x$grub_cv_check_end_symbol" = xyes; then
-  AC_DEFINE([END_SYMBOL], [end])
-elif test "x$grub_cv_check_uscore_end_symbol" = xyes; then
-  AC_DEFINE([END_SYMBOL], [_end])
-else
-  AC_MSG_ERROR([neither end nor _end is defined])
-fi
-])
-
 dnl Check if the C compiler has a bug while using nested functions when
 dnl mregparm is used on the i386.  Some gcc versions do not pass the third
 dnl parameter correctly to the nested function.
diff --git a/conf/i386-pc-cygwin-img-ld.sc b/conf/i386-pc-cygwin-img-ld.sc
deleted file mode 100644
index a41cac7..0000000
--- a/conf/i386-pc-cygwin-img-ld.sc
+++ /dev/null
@@ -1,53 +0,0 @@
-/* Linker script to create grub .img files on Cygwin.  */
-
-SECTIONS
-{
-  .text :
-  {
-    start = . ;
-    *(.text)
-    etext = . ;
-  }
-  .data :
-  {
-    __data_start__ = . ;
-    *(.data)
-    __data_end__ = . ;
-  }
-  .rdata :
-  {
-    __rdata_start__ = . ;
-    *(.rdata)
-    __rdata_end__ = . ;
-  }
-  .pdata :
-  {
-    *(.pdata)
-    edata = . ;
-  }
-  .bss :
-  {
-    __bss_start__ = . ;
-    *(.bss)
-    __common_start__ = . ;
-    *(COMMON)
-    __bss_end__ = . ;
-  }
-  .edata :
-  {
-    *(.edata)
-    end = . ;
-  }
-  .stab :
-  {
-    *(.stab)
-  }
-  .stabstr :
-  {
-    *(.stabstr)
-  }
-}
-
-ASSERT("__rdata_end__"=="edata", ".pdata not empty")
-ASSERT("__bss_end__"  =="end"  , ".edata not empty")
-
diff --git a/conf/i386-pc.lds b/conf/i386-pc.lds
new file mode 100644
index 0000000..a41cac7
--- /dev/null
+++ b/conf/i386-pc.lds
@@ -0,0 +1,53 @@
+/* Linker script to create grub .img files on Cygwin.  */
+
+SECTIONS
+{
+  .text :
+  {
+    start = . ;
+    *(.text)
+    etext = . ;
+  }
+  .data :
+  {
+    __data_start__ = . ;
+    *(.data)
+    __data_end__ = . ;
+  }
+  .rdata :
+  {
+    __rdata_start__ = . ;
+    *(.rdata)
+    __rdata_end__ = . ;
+  }
+  .pdata :
+  {
+    *(.pdata)
+    edata = . ;
+  }
+  .bss :
+  {
+    __bss_start__ = . ;
+    *(.bss)
+    __common_start__ = . ;
+    *(COMMON)
+    __bss_end__ = . ;
+  }
+  .edata :
+  {
+    *(.edata)
+    end = . ;
+  }
+  .stab :
+  {
+    *(.stab)
+  }
+  .stabstr :
+  {
+    *(.stabstr)
+  }
+}
+
+ASSERT("__rdata_end__"=="edata", ".pdata not empty")
+ASSERT("__bss_end__"  =="end"  , ".edata not empty")
+
diff --git a/configure.ac b/configure.ac
index d84e2b6..a048828 100644
--- a/configure.ac
+++ b/configure.ac
@@ -209,10 +209,10 @@ AC_CHECK_FUNCS(posix_memalign memalign asprintf)
 
 # Use linker script if present, otherwise use builtin -N script.
 AC_MSG_CHECKING([for option to link raw image])
-if test -f "${srcdir}/conf/${target_cpu}-${platform}-${host_os}-img-ld.sc"; 
then
-  
TARGET_IMG_LDSCRIPT='$(top_srcdir)'"/conf/${target_cpu}-${platform}-${host_os}-img-ld.sc"
+if test -f "${srcdir}/conf/${target_cpu}-${platform}.lds"; then
+  TARGET_IMG_LDSCRIPT='$(top_srcdir)'"/conf/${target_cpu}-${platform}.lds"
   TARGET_IMG_LDFLAGS="-Wl,-T${TARGET_IMG_LDSCRIPT}"
-  
TARGET_IMG_LDFLAGS_AC="-Wl,-T${srcdir}/conf/${target_cpu}-${platform}-${host_os}-img-ld.sc"
+  TARGET_IMG_LDFLAGS_AC="-Wl,-T${srcdir}/conf/${target_cpu}-${platform}.lds"
 else
   TARGET_IMG_LDSCRIPT=
   TARGET_IMG_LDFLAGS='-Wl,-N'
@@ -383,10 +383,6 @@ if test "x$target_cpu" = xi386; then
     # Check symbols provided by linker script.
     CFLAGS="$TARGET_CFLAGS -nostdlib $TARGET_IMG_LDFLAGS_AC 
-Wl,-Ttext,8000,--defsym,___main=0x8100"
   fi
-  if test "x$platform" = xpc; then
-    grub_CHECK_BSS_START_SYMBOL
-    grub_CHECK_END_SYMBOL
-  fi
   CFLAGS="$TARGET_CFLAGS"
   grub_I386_ASM_PREFIX_REQUIREMENT
   grub_I386_ASM_ADDR32
diff --git a/kern/i386/pc/startup.S b/kern/i386/pc/startup.S
index 8e8b661..471a8d3 100644
--- a/kern/i386/pc/startup.S
+++ b/kern/i386/pc/startup.S
@@ -241,7 +241,7 @@ codestart:
        addl    %ecx, %esi
        addl    $_start, %esi
        decl    %esi
-       movl    $END_SYMBOL, %edi
+       movl    $__bss_end__, %edi
        addl    %ecx, %edi
        decl    %edi
        std
@@ -250,10 +250,10 @@ codestart:
 #endif
        
        /* clean out the bss */
-       movl    $BSS_START_SYMBOL, %edi
+       movl    $__bss_start__, %edi
 
        /* compute the bss length */
-       movl    $END_SYMBOL, %ecx
+       movl    $__bss_end__, %ecx
        subl    %edi, %ecx
                        
        /* clean out */
@@ -285,7 +285,7 @@ VARIABLE(grub_start_addr)
        .long   _start
 
 VARIABLE(grub_end_addr)
-       .long   END_SYMBOL
+       .long   __bss_end__
        
 VARIABLE(grub_apm_bios_info)
        .word   0       /* version */