uml: clean up TASK_SIZE usage

Clean up the calculation and use of the usable address space size on the host.

task_size is gone, replaced with TASK_SIZE, which is calculated from
CONFIG_TOP_ADDR.  get_kmem_end and set_task_sizes_skas are also gone.

host_task_size, which refers to the entire address space usable by the UML
kernel and which may be larger than the address space usable by a UML process,
since that has to end on a pgdir boundary, is replaced by CONFIG_TOP_ADDR.

STACK_TOP is now TASK_SIZE minus the two stub pages.

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>

1 files changed, 2 insertions, 20 deletions

diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 1139e07b968..9ba39ab5f4b 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -101,8 +101,6 @@ const struct seq_operations cpuinfo_op = {
 };
 
 /* Set in linux_main */
-unsigned long host_task_size;
-unsigned long task_size;
 unsigned long uml_physmem;
 unsigned long uml_reserved; /* Also modified in mem_init */
 unsigned long start_vm;
@@ -234,20 +232,6 @@ EXPORT_SYMBOL(end_iomem);
 
 extern char __binary_start;
 
-static unsigned long set_task_sizes_skas(unsigned long *task_size_out)
-{
-	/* Round up to the nearest 4M */
-	unsigned long host_task_size = ROUND_4M((unsigned long)
-						&host_task_size);
-
-	if (!skas_needs_stub)
-		*task_size_out = host_task_size;
-	else
-		*task_size_out = STUB_START & PGDIR_MASK;
-
-	return host_task_size;
-}
-
 int __init linux_main(int argc, char **argv)
 {
 	unsigned long avail, diff;
@@ -278,8 +262,6 @@ int __init linux_main(int argc, char **argv)
 
 	printf("UML running in %s mode\n", mode);
 
-	host_task_size = set_task_sizes_skas(&task_size);
-
 	brk_start = (unsigned long) sbrk(0);
 
 	/*
@@ -304,7 +286,7 @@ int __init linux_main(int argc, char **argv)
 
 	highmem = 0;
 	iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
-	max_physmem = get_kmem_end() - uml_physmem - iomem_size - MIN_VMALLOC;
+	max_physmem = CONFIG_TOP_ADDR - uml_physmem - iomem_size - MIN_VMALLOC;
 
 	/*
 	 * Zones have to begin on a 1 << MAX_ORDER page boundary,
@@ -336,7 +318,7 @@ int __init linux_main(int argc, char **argv)
 	}
 
 	virtmem_size = physmem_size;
-	avail = get_kmem_end() - start_vm;
+	avail = CONFIG_TOP_ADDR - start_vm;
 	if (physmem_size > avail)
 		virtmem_size = avail;
 	end_vm = start_vm + virtmem_size;