[PATCH] uml: fix static binary segfault

When UML is built as a static binary, it segfaults when run.  The reason is
that a memory hole that is present in dynamic binaries isn't there in static
binaries, and it contains essential stuff.

This fix removes the code which maps some anonymous memory into that hole and
cleans up some related code.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 8 insertions, 5 deletions

diff --git a/arch/um/kernel/uml.lds.S b/arch/um/kernel/uml.lds.S
index af11915..8eca47a 100644
--- a/arch/um/kernel/uml.lds.S
+++ b/arch/um/kernel/uml.lds.S
@@ -7,13 +7,16 @@ jiffies = jiffies_64;
 
 SECTIONS
 {
-  /*This must contain the right address - not quite the default ELF one.*/
+  /* This must contain the right address - not quite the default ELF one.*/
   PROVIDE (__executable_start = START);
-  . = START + SIZEOF_HEADERS;
+  /* Static binaries stick stuff here, like the sigreturn trampoline,
+   * invisibly to objdump.  So, just make __binary_start equal to the very
+   * beginning of the executable, and if there are unmapped pages after this,
+   * they are forever unusable.
+   */
+  __binary_start = START;
 
-  /* Used in arch/um/kernel/mem.c. Any memory between START and __binary_start
-   * is remapped.*/
-  __binary_start = .;
+  . = START + SIZEOF_HEADERS;
 
 #ifdef MODE_TT
   .remap_data : { UNMAP_PATH (.data .bss) }