[PATCH] uml: fix linkage of tt mode against NPTL

With Al Viro <viro@parcelfarce.linux.theplanet.co.uk>

To make sure switcheroo() can execute when we remap all the executable
image, we used a trick to make it use a local copy of errno...  this trick
does not work with NPTL glibc, only with LinuxThreads, so use another
(simpler) one to make it work anyway.

Hopefully, a lot improved thanks to merging with the version of Al Viro
(which had his part of problems, though, i.e.  removing a fix to another
bug and not fixing the problem on i386).

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

3 files changed, 3 insertions, 58 deletions

diff --git a/arch/um/kernel/tt/Makefile b/arch/um/kernel/tt/Makefile
index c3faea21a996..3fd2554e60b6 100644
--- a/arch/um/kernel/tt/Makefile
+++ b/arch/um/kernel/tt/Makefile
@@ -3,10 +3,6 @@
 # Licensed under the GPL
 #
 
-extra-y := unmap_fin.o
-targets := unmap.o
-clean-files := unmap_tmp.o
-
 obj-y = exec_kern.o exec_user.o gdb.o ksyms.o mem.o mem_user.o process_kern.o \
         syscall_kern.o syscall_user.o time.o tlb.o tracer.o trap_user.o \
         uaccess.o uaccess_user.o
@@ -16,14 +12,3 @@ obj-$(CONFIG_PT_PROXY) += gdb_kern.o ptproxy/
 USER_OBJS := gdb.o time.o tracer.o
 
 include arch/um/scripts/Makefile.rules
-
-UNMAP_CFLAGS := $(patsubst -pg -DPROFILING,,$(USER_CFLAGS))
-UNMAP_CFLAGS := $(patsubst -fprofile-arcs -ftest-coverage,,$(UNMAP_CFLAGS))
-
-#XXX: partially copied from arch/um/scripts/Makefile.rules
-$(obj)/unmap.o: c_flags = -Wp,-MD,$(depfile) $(UNMAP_CFLAGS)
-
-$(obj)/unmap_fin.o : $(obj)/unmap.o
-        $(LD) -r -o $(obj)/unmap_tmp.o $< $(shell $(CC) -print-file-name=libc.a)
-        $(OBJCOPY) $(obj)/unmap_tmp.o $@ -G switcheroo
-
diff --git a/arch/um/kernel/tt/unmap.c b/arch/um/kernel/tt/unmap.c
deleted file mode 100644
index 3f7aecdbe532..000000000000
--- a/arch/um/kernel/tt/unmap.c
+++ /dev/null
@@ -1,31 +0,0 @@
-/* 
- * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
- * Licensed under the GPL
- */
-
-#include <sys/mman.h>
-
-int switcheroo(int fd, int prot, void *from, void *to, int size)
-{
-        if(munmap(to, size) < 0){
-                return(-1);
-        }
-        if(mmap(to, size, prot, MAP_SHARED | MAP_FIXED, fd, 0) != to){
-                return(-1);
-        }
-        if(munmap(from, size) < 0){
-                return(-1);
-        }
-        return(0);
-}
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
diff --git a/arch/um/kernel/uml.lds.S b/arch/um/kernel/uml.lds.S
index dd5355500bdc..61dfd4fef752 100644
--- a/arch/um/kernel/uml.lds.S
+++ b/arch/um/kernel/uml.lds.S
@@ -14,19 +14,10 @@ SECTIONS
   /* Used in arch/um/kernel/mem.c. Any memory between START and __binary_start
    * is remapped.*/
   __binary_start = .;
-#ifdef MODE_TT
-  .thread_private : {
-    __start_thread_private = .;
-    errno = .;
-    . += 4;
-    arch/um/kernel/tt/unmap_fin.o (.data)
-    __end_thread_private = .;
-  }
-  . = ALIGN(4096);
-  .remap : { arch/um/kernel/tt/unmap_fin.o (.text) }
 
-  /* We want it only if we are in MODE_TT. In both cases, however, when MODE_TT
-   * is off the resulting binary segfaults.*/
+#ifdef MODE_TT
+  .remap_data : { arch/um/sys-SUBARCH/unmap_fin.o (.data .bss) }
+  .remap : { arch/um/sys-SUBARCH/unmap_fin.o (.text) }
 
   . = ALIGN(4096);              /* Init code and data */
 #endif