uml: fix stub address calculations

The calculation of CONFIG_STUB_CODE and CONFIG_STUB_DATA didn't take into
account anything but 3G/1G and 2G/2G, leaving the other vmsplits out in the
cold.

I'd rather not duplicate the four known host vmsplit cases for each of these
symbols.  I'd also like to calculate them based on the highest userspace
address.

The Kconfig language seems not to allow calculation of hex constants, so I
moved this to as-layout.h.  CONFIG_STUB_CODE, CONFIG_STUB_DATA, and
CONFIG_STUB_START are now gone.  In their place are STUB_CODE, STUB_DATA, and
STUB_START in as-layout.h.

i386 and x86_64 seem to differ as to whether an unadorned constant is an int
or a long, so I cast them to unsigned long so they can be printed
consistently.  However, they are also used in stub.S, where C types don't work
so well.  So, there are ASM_ versions of these constants for use in stub.S.  I
also ifdef-ed the non-asm-friendly portion of as-layout.h.

With this in place, most of the rest of this patch is changing CONFIG_STUB_*
to STUB_*, except in stub.S, where they are changed to ASM_STUB_*.

defconfig has the old symbols deleted.

I also print these addresses out in case there is any problem mapping them on
the host.

The two stub.S files had some trailing whitespace, so that is cleaned up here.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 37 insertions, 11 deletions

diff --git a/arch/um/include/as-layout.h b/arch/um/include/as-layout.h
index 2f16a1c7d61..a5cdf953e04 100644
--- a/arch/um/include/as-layout.h
+++ b/arch/um/include/as-layout.h
@@ -6,6 +6,28 @@
 #ifndef __START_H__
 #define __START_H__
 
+#include "uml-config.h"
+#include "kern_constants.h"
+
+/*
+ * Assembly doesn't want any casting, but C does, so define these
+ * without casts here, and define new symbols with casts inside the C
+ * section.
+ */
+#define ASM_STUB_CODE (UML_CONFIG_TOP_ADDR - 2 * UM_KERN_PAGE_SIZE)
+#define ASM_STUB_DATA (UML_CONFIG_TOP_ADDR - UM_KERN_PAGE_SIZE)
+#define ASM_STUB_START ASM_STUB_CODE
+
+/*
+ * This file is included by the assembly stubs, which just want the
+ * definitions above.
+ */
+#ifndef __ASSEMBLY__
+
+#define STUB_CODE ((unsigned long) ASM_STUB_CODE)
+#define STUB_DATA ((unsigned long) ASM_STUB_DATA)
+#define STUB_START ((unsigned long) ASM_STUB_START)
+
 #include "sysdep/ptrace.h"
 
 struct cpu_task {
@@ -32,3 +54,5 @@ extern int linux_main(int argc, char **argv);
 extern void (*sig_info[])(int, struct uml_pt_regs *);
 
 #endif
+
+#endif
diff --git a/arch/um/include/sysdep-i386/stub.h b/arch/um/include/sysdep-i386/stub.h
index 19c85f330fc..8c097b87fca 100644
--- a/arch/um/include/sysdep-i386/stub.h
+++ b/arch/um/include/sysdep-i386/stub.h
@@ -9,6 +9,7 @@
 #include <sys/mman.h>
 #include <asm/ptrace.h>
 #include <asm/unistd.h>
+#include "as-layout.h"
 #include "stub-data.h"
 #include "kern_constants.h"
 #include "uml-config.h"
@@ -89,12 +90,12 @@ static inline void remap_stack(int fd, unsigned long offset)
 {
 	__asm__ volatile ("movl %%eax,%%ebp ; movl %0,%%eax ; int $0x80 ;"
 			  "movl %7, %%ebx ; movl %%eax, (%%ebx)"
-			  : : "g" (STUB_MMAP_NR), "b" (UML_CONFIG_STUB_DATA), 
-			    "c" (UM_KERN_PAGE_SIZE), 
+			  : : "g" (STUB_MMAP_NR), "b" (STUB_DATA),
+			    "c" (UM_KERN_PAGE_SIZE),
 			    "d" (PROT_READ | PROT_WRITE),
-			    "S" (MAP_FIXED | MAP_SHARED), "D" (fd), 
-			    "a" (offset), 
-			    "i" (&((struct stub_data *) UML_CONFIG_STUB_DATA)->err) 
+			    "S" (MAP_FIXED | MAP_SHARED), "D" (fd),
+			    "a" (offset),
+			    "i" (&((struct stub_data *) STUB_DATA)->err)
 			  : "memory");
 }
 
diff --git a/arch/um/include/sysdep-x86_64/stub.h b/arch/um/include/sysdep-x86_64/stub.h
index 92e989f8176..655f9c2de3a 100644
--- a/arch/um/include/sysdep-x86_64/stub.h
+++ b/arch/um/include/sysdep-x86_64/stub.h
@@ -9,6 +9,7 @@
 #include <sys/mman.h>
 #include <asm/unistd.h>
 #include <sysdep/ptrace_user.h>
+#include "as-layout.h"
 #include "stub-data.h"
 #include "kern_constants.h"
 #include "uml-config.h"
@@ -94,13 +95,13 @@ static inline void remap_stack(long fd, unsigned long offset)
 {
 	__asm__ volatile ("movq %4,%%r10 ; movq %5,%%r8 ; "
 			  "movq %6, %%r9; " __syscall "; movq %7, %%rbx ; "
-			  "movq %%rax, (%%rbx)": 
-			  : "a" (STUB_MMAP_NR), "D" (UML_CONFIG_STUB_DATA), 
-			    "S" (UM_KERN_PAGE_SIZE), 
-			    "d" (PROT_READ | PROT_WRITE), 
-                            "g" (MAP_FIXED | MAP_SHARED), "g" (fd), 
+			  "movq %%rax, (%%rbx)":
+			  : "a" (STUB_MMAP_NR), "D" (STUB_DATA),
+			    "S" (UM_KERN_PAGE_SIZE),
+			    "d" (PROT_READ | PROT_WRITE),
+                            "g" (MAP_FIXED | MAP_SHARED), "g" (fd),
 			    "g" (offset),
-			    "i" (&((struct stub_data *) UML_CONFIG_STUB_DATA)->err)
+			    "i" (&((struct stub_data *) STUB_DATA)->err)
 			  : __syscall_clobber, "r10", "r8", "r9" );
 }