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authorJeff Dike <jdike@addtoit.com>2008-02-08 04:22:07 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-08 09:22:42 -0800
commit536788fe2d28e11db6aeda74207d95d750fb761f (patch)
tree73df2d3a46c542c71d3a84c20c8fd1ce617386a3 /include/asm-um
parent2f569afd9ced9ebec9a6eb3dbf6f83429be0a7b4 (diff)
downloadlinux-stericsson-536788fe2d28e11db6aeda74207d95d750fb761f.tar.gz
uml: runtime host VMSPLIT detection
Calculate TASK_SIZE at run-time by figuring out the host's VMSPLIT - this is needed on i386 if UML is to run on hosts with varying VMSPLITs without recompilation. TASK_SIZE is now defined in terms of a variable, task_size. This gets rid of an include of pgtable.h from processor.h, which can cause include loops. On i386, task_size is calculated early in boot by probing the address space in a binary search to figure out where the boundary between usable and non-usable memory is. This tries to make sure that a page that is considered to be in userspace is, or can be made, read-write. I'm concerned about a system-global VDSO page in kernel memory being hit and considered to be a userspace page. On x86_64, task_size is just the old value of CONFIG_TOP_ADDR. A bunch of config variable are gone now. CONFIG_TOP_ADDR is directly replaced by TASK_SIZE. NEST_LEVEL is gone since the relocation of the stubs makes it irrelevant. All the HOST_VMSPLIT stuff is gone. All references to these in arch/um/Makefile are also gone. I noticed and fixed a missing extern in os.h when adding os_get_task_size. Note: This has been revised to fix the 32-bit UML on 64-bit host bug that Miklos ran into. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/asm-um')
-rw-r--r--include/asm-um/fixmap.h3
-rw-r--r--include/asm-um/processor-generic.h5
2 files changed, 5 insertions, 3 deletions
diff --git a/include/asm-um/fixmap.h b/include/asm-um/fixmap.h
index 89a87c18b927..9d2be52b8655 100644
--- a/include/asm-um/fixmap.h
+++ b/include/asm-um/fixmap.h
@@ -1,6 +1,7 @@
#ifndef __UM_FIXMAP_H
#define __UM_FIXMAP_H
+#include <asm/processor.h>
#include <asm/system.h>
#include <asm/kmap_types.h>
#include <asm/archparam.h>
@@ -57,7 +58,7 @@ extern void __set_fixmap (enum fixed_addresses idx,
* at the top of mem..
*/
-#define FIXADDR_TOP (CONFIG_TOP_ADDR - 2 * PAGE_SIZE)
+#define FIXADDR_TOP (TASK_SIZE - 2 * PAGE_SIZE)
#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
diff --git a/include/asm-um/processor-generic.h b/include/asm-um/processor-generic.h
index 7a1624cdaf7e..bed668824b5f 100644
--- a/include/asm-um/processor-generic.h
+++ b/include/asm-um/processor-generic.h
@@ -11,7 +11,6 @@ struct pt_regs;
struct task_struct;
#include "asm/ptrace.h"
-#include "asm/pgtable.h"
#include "registers.h"
#include "sysdep/archsetjmp.h"
@@ -92,7 +91,9 @@ static inline void mm_copy_segments(struct mm_struct *from_mm,
/*
* User space process size: 3GB (default).
*/
-#define TASK_SIZE (CONFIG_TOP_ADDR & PGDIR_MASK)
+extern unsigned long task_size;
+
+#define TASK_SIZE (task_size)
#undef STACK_TOP
#undef STACK_TOP_MAX