Patchwork [2/3] Fix text relocations in linux-user targets

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Submitter Kirill A. Shutemov
Date Sept. 11, 2009, 11:17 p.m.
Message ID <1252711075-32404-2-git-send-email-kirill@shutemov.name>
Download mbox | patch
Permalink /patch/33488/
State Superseded
Headers show

Comments

Kirill A. Shutemov - Sept. 11, 2009, 11:17 p.m.
There is a link hack in linux-user which produces an executable that
looks like PIE, but always has text relocations since all object files
isn't position-independent (compiled without -fpic/-fpie). Dynamic loader
has to do more work to load a binary with text relocations.

The best way to keep this functionality is to build a true PIE without
text relocations.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
---
 configure         |   12 +-----------
 linux-user/main.c |   26 --------------------------
 2 files changed, 1 insertions(+), 37 deletions(-)

Patch

diff --git a/configure b/configure
index 1ecb1ab..b2f52b2 100755
--- a/configure
+++ b/configure
@@ -2357,16 +2357,6 @@  fi
 linker_script="-Wl,-T../config-host.ld -Wl,-T,\$(SRC_PATH)/\$(ARCH).ld"
 if test "$target_linux_user" = "yes" -o "$target_bsd_user" = "yes" ; then
   case "$ARCH" in
-  i386)
-    if test "$gprof" = "yes" -o "$static" = "yes" ; then
-      ldflags="$linker_script $ldflags"
-    else
-      # WARNING: this LDFLAGS is _very_ tricky : qemu is an ELF shared object
-      # that the kernel ELF loader considers as an executable. I think this
-      # is the simplest way to make it self virtualizable!
-      ldflags="-Wl,-shared $ldflags"
-    fi
-    ;;
   sparc)
     # -static is used to avoid g1/g3 usage by the dynamic linker
     ldflags="$linker_script -static $ldflags"
@@ -2374,7 +2364,7 @@  if test "$target_linux_user" = "yes" -o "$target_bsd_user" = "yes" ; then
   ia64)
     ldflags="-Wl,-G0 $linker_script -static $ldflags"
     ;;
-  x86_64|ppc|ppc64|s390|sparc64|alpha|arm|m68k|mips|mips64)
+  i386|x86_64|ppc|ppc64|s390|sparc64|alpha|arm|m68k|mips|mips64)
     ldflags="$linker_script $ldflags"
     ;;
   esac
diff --git a/linux-user/main.c b/linux-user/main.c
index a628c01..81a1ada 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -48,32 +48,6 @@  int have_guest_base;
 static const char *interp_prefix = CONFIG_QEMU_PREFIX;
 const char *qemu_uname_release = CONFIG_UNAME_RELEASE;
 
-#if defined(__i386__) && !defined(CONFIG_STATIC)
-/* Force usage of an ELF interpreter even if it is an ELF shared
-   object ! */
-const char interp[] __attribute__((section(".interp"))) = "/lib/ld-linux.so.2";
-#endif
-
-/* for recent libc, we add these dummy symbols which are not declared
-   when generating a linked object (bug in ld ?) */
-#if (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 3)) && !defined(CONFIG_STATIC)
-asm(".globl __preinit_array_start\n"
-    ".globl __preinit_array_end\n"
-    ".globl __init_array_start\n"
-    ".globl __init_array_end\n"
-    ".globl __fini_array_start\n"
-    ".globl __fini_array_end\n"
-    ".section \".rodata\"\n"
-    "__preinit_array_start:\n"
-    "__preinit_array_end:\n"
-    "__init_array_start:\n"
-    "__init_array_end:\n"
-    "__fini_array_start:\n"
-    "__fini_array_end:\n"
-    ".long 0\n"
-    ".previous\n");
-#endif
-
 /* XXX: on x86 MAP_GROWSDOWN only works if ESP <= address + 32, so
    we allocate a bigger stack. Need a better solution, for example
    by remapping the process stack directly at the right place */