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>

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>
Jeff Dike · Linus Torvalds
1 parent b7c000cbc4
Showing 11 changed files with 23 additions and 49 deletions Side-by-side Diff
arch/um/include/as-layout.h
arch/um/include/common-offsets.h
arch/um/include/mem_user.h
arch/um/kernel/exec.c
arch/um/kernel/ksyms.c
arch/um/kernel/physmem.c
arch/um/kernel/tlb.c
arch/um/kernel/um_arch.c
include/asm-um/a.out.h
include/asm-um/fixmap.h
include/asm-um/processor-generic.h
@@ -29,9 +29,20 @@
 #define _AC(X, Y)	__AC(X, Y)
 #endif
  
+/*
+ * The "- 1"'s are to avoid gcc complaining about integer overflows
+ * and unrepresentable decimal constants.  With 3-level page tables,
+ * TASK_SIZE is 0x80000000, which gets turned into its signed decimal
+ * equivalent in asm-offsets.s.  gcc then complains about that being
+ * unsigned only in C90.  To avoid that, UM_TASK_SIZE is defined as
+ * TASK_SIZE - 1.  To compensate, we need to add the 1 back here.
+ * However, adding it back to UM_TASK_SIZE produces more gcc
+ * complaints.  So, I adjust the thing being subtracted from
+ * UM_TASK_SIZE instead.  Bah.
+ */
 #define STUB_CODE _AC((unsigned long), \
-		      UML_CONFIG_TOP_ADDR - 2 * UM_KERN_PAGE_SIZE)
-#define STUB_DATA _AC((unsigned long), UML_CONFIG_TOP_ADDR - UM_KERN_PAGE_SIZE)
+		      UM_TASK_SIZE - (2 * UM_KERN_PAGE_SIZE - 1))
+#define STUB_DATA _AC((unsigned long), UM_TASK_SIZE - (UM_KERN_PAGE_SIZE - 1))
 #define STUB_START _AC(, STUB_CODE)
  
 #ifndef __ASSEMBLY__
@@ -39,4 +39,7 @@
 DEFINE(UM_USEC_PER_SEC, USEC_PER_SEC);
 DEFINE(UM_NSEC_PER_SEC, NSEC_PER_SEC);
 DEFINE(UM_NSEC_PER_USEC, NSEC_PER_USEC);
+
+/* See as-layout.h for an explanation of the "- 1".  Bah. */
+DEFINE(UM_TASK_SIZE, TASK_SIZE - 1);
@@ -46,9 +46,6 @@
  
 #define ROUND_4M(n) ((((unsigned long) (n)) + (1 << 22)) & ~((1 << 22) - 1))
  
-extern unsigned long host_task_size;
-extern unsigned long task_size;
-
 extern int init_mem_user(void);
 extern void setup_memory(void *entry);
 extern unsigned long find_iomem(char *driver, unsigned long *len_out);
@@ -62,7 +59,6 @@
 extern void unmap_physmem(void);
 extern void map_memory(unsigned long virt, unsigned long phys,
 		       unsigned long len, int r, int w, int x);
-extern unsigned long get_kmem_end(void);
  
 #endif
@@ -19,7 +19,7 @@
 void flush_thread(void)
 {
 	void *data = NULL;
-	unsigned long end = proc_mm ? task_size : STUB_START;
+	unsigned long end = proc_mm ? TASK_SIZE : STUB_START;
 	int ret;
  
 	arch_flush_thread(&current->thread.arch);
@@ -18,11 +18,8 @@
 EXPORT_SYMBOL(get_signals);
 EXPORT_SYMBOL(kernel_thread);
 EXPORT_SYMBOL(sys_waitpid);
-EXPORT_SYMBOL(task_size);
 EXPORT_SYMBOL(flush_tlb_range);
-EXPORT_SYMBOL(host_task_size);
 EXPORT_SYMBOL(arch_validate);
-EXPORT_SYMBOL(get_kmem_end);
  
 EXPORT_SYMBOL(high_physmem);
 EXPORT_SYMBOL(empty_zero_page);
@@ -55,16 +55,6 @@
 	return 0;
 }
  
-/* Changed during early boot */
-static unsigned long kmem_top = 0;
-
-unsigned long get_kmem_end(void)
-{
-	if (kmem_top == 0)
-		kmem_top = host_task_size - 1024 * 1024;
-	return kmem_top;
-}
-
 void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
 		int r, int w, int x)
 {
@@ -511,7 +511,7 @@
 	if (atomic_read(&mm->mm_users) == 0)
 		return;
  
-	end = proc_mm ? task_size : STUB_START;
+	end = proc_mm ? TASK_SIZE : STUB_START;
 	fix_range(mm, 0, end, 0);
 }
  
@@ -101,8 +101,6 @@
 };
  
 /* 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 @@
  
 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 @@
  
 	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 @@
  
 	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 @@
 	}
  
 	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;
@@ -13,11 +13,9 @@
  
 extern unsigned long stacksizelim;
  
-extern unsigned long host_task_size;
-
 #define STACK_ROOM (stacksizelim)
  
-#define STACK_TOP task_size
+#define STACK_TOP (TASK_SIZE - 2 * PAGE_SIZE)
  
 #define STACK_TOP_MAX STACK_TOP
  
@@ -56,9 +56,8 @@
  * the start of the fixmap, and leave one page empty
  * at the top of mem..
  */
-extern unsigned long get_kmem_end(void);
  
-#define FIXADDR_TOP	(get_kmem_end() - 0x2000)
+#define FIXADDR_TOP	(CONFIG_TOP_ADDR - 2 * PAGE_SIZE)
 #define FIXADDR_SIZE	(__end_of_fixed_addresses << PAGE_SHIFT)
 #define FIXADDR_START	(FIXADDR_TOP - FIXADDR_SIZE)
  
@@ -94,9 +94,7 @@
 /*
  * User space process size: 3GB (default).
  */
-extern unsigned long task_size;
-
-#define TASK_SIZE	(task_size)
+#define TASK_SIZE (CONFIG_TOP_ADDR & PGDIR_MASK)
  
 /* This decides where the kernel will search for a free chunk of vm
  * space during mmap's.
...	...	@@ -29,9 +29,20 @@
29	29	#define _AC(X, Y) __AC(X, Y)
30	30	#endif
31	31
	32	+/*
	33	+ * The "- 1"'s are to avoid gcc complaining about integer overflows
	34	+ * and unrepresentable decimal constants. With 3-level page tables,
	35	+ * TASK_SIZE is 0x80000000, which gets turned into its signed decimal
	36	+ * equivalent in asm-offsets.s. gcc then complains about that being
	37	+ * unsigned only in C90. To avoid that, UM_TASK_SIZE is defined as
	38	+ * TASK_SIZE - 1. To compensate, we need to add the 1 back here.
	39	+ * However, adding it back to UM_TASK_SIZE produces more gcc
	40	+ * complaints. So, I adjust the thing being subtracted from
	41	+ * UM_TASK_SIZE instead. Bah.
	42	+ */
32	43	#define STUB_CODE _AC((unsigned long), \
33		- UML_CONFIG_TOP_ADDR - 2 * UM_KERN_PAGE_SIZE)
34		-#define STUB_DATA _AC((unsigned long), UML_CONFIG_TOP_ADDR - UM_KERN_PAGE_SIZE)
	44	+ UM_TASK_SIZE - (2 * UM_KERN_PAGE_SIZE - 1))
	45	+#define STUB_DATA _AC((unsigned long), UM_TASK_SIZE - (UM_KERN_PAGE_SIZE - 1))
35	46	#define STUB_START _AC(, STUB_CODE)
36	47
37	48	#ifndef __ASSEMBLY__
...	...	@@ -39,4 +39,7 @@
39	39	DEFINE(UM_USEC_PER_SEC, USEC_PER_SEC);
40	40	DEFINE(UM_NSEC_PER_SEC, NSEC_PER_SEC);
41	41	DEFINE(UM_NSEC_PER_USEC, NSEC_PER_USEC);
	42	+
	43	+/* See as-layout.h for an explanation of the "- 1". Bah. */
	44	+DEFINE(UM_TASK_SIZE, TASK_SIZE - 1);
...	...	@@ -46,9 +46,6 @@
46	46
47	47	#define ROUND_4M(n) ((((unsigned long) (n)) + (1 << 22)) & ~((1 << 22) - 1))
48	48
49		-extern unsigned long host_task_size;
50		-extern unsigned long task_size;
51		-
52	49	extern int init_mem_user(void);
53	50	extern void setup_memory(void *entry);
54	51	extern unsigned long find_iomem(char driver, unsigned long len_out);
...	...	@@ -62,7 +59,6 @@
62	59	extern void unmap_physmem(void);
63	60	extern void map_memory(unsigned long virt, unsigned long phys,
64	61	unsigned long len, int r, int w, int x);
65		-extern unsigned long get_kmem_end(void);
66	62
67	63	#endif
...	...	@@ -19,7 +19,7 @@
19	19	void flush_thread(void)
20	20	{
21	21	void *data = NULL;
22		- unsigned long end = proc_mm ? task_size : STUB_START;
	22	+ unsigned long end = proc_mm ? TASK_SIZE : STUB_START;
23	23	int ret;
24	24
25	25	arch_flush_thread(&current->thread.arch);
...	...	@@ -18,11 +18,8 @@
18	18	EXPORT_SYMBOL(get_signals);
19	19	EXPORT_SYMBOL(kernel_thread);
20	20	EXPORT_SYMBOL(sys_waitpid);
21		-EXPORT_SYMBOL(task_size);
22	21	EXPORT_SYMBOL(flush_tlb_range);
23		-EXPORT_SYMBOL(host_task_size);
24	22	EXPORT_SYMBOL(arch_validate);
25		-EXPORT_SYMBOL(get_kmem_end);
26	23
27	24	EXPORT_SYMBOL(high_physmem);
28	25	EXPORT_SYMBOL(empty_zero_page);
...	...	@@ -55,16 +55,6 @@
55	55	return 0;
56	56	}
57	57
58		-/* Changed during early boot */
59		-static unsigned long kmem_top = 0;
60		-
61		-unsigned long get_kmem_end(void)
62		-{
63		- if (kmem_top == 0)
64		- kmem_top = host_task_size - 1024 * 1024;
65		- return kmem_top;
66		-}
67		-
68	58	void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
69	59	int r, int w, int x)
70	60	{
...	...	@@ -511,7 +511,7 @@
511	511	if (atomic_read(&mm->mm_users) == 0)
512	512	return;
513	513
514		- end = proc_mm ? task_size : STUB_START;
	514	+ end = proc_mm ? TASK_SIZE : STUB_START;
515	515	fix_range(mm, 0, end, 0);
516	516	}
517	517
...	...	@@ -101,8 +101,6 @@
101	101	};
102	102
103	103	/* Set in linux_main */
104		-unsigned long host_task_size;
105		-unsigned long task_size;
106	104	unsigned long uml_physmem;
107	105	unsigned long uml_reserved; /* Also modified in mem_init */
108	106	unsigned long start_vm;
...	...	@@ -234,20 +232,6 @@
234	232
235	233	extern char __binary_start;
236	234
237		-static unsigned long set_task_sizes_skas(unsigned long *task_size_out)
238		-{
239		- /* Round up to the nearest 4M */
240		- unsigned long host_task_size = ROUND_4M((unsigned long)
241		- &host_task_size);
242		-
243		- if (!skas_needs_stub)
244		- *task_size_out = host_task_size;
245		- else
246		- *task_size_out = STUB_START & PGDIR_MASK;
247		-
248		- return host_task_size;
249		-}
250		-
251	235	int __init linux_main(int argc, char **argv)
252	236	{
253	237	unsigned long avail, diff;
...	...	@@ -278,8 +262,6 @@
278	262
279	263	printf("UML running in %s mode\n", mode);
280	264
281		- host_task_size = set_task_sizes_skas(&task_size);
282		-
283	265	brk_start = (unsigned long) sbrk(0);
284	266
285	267	/*
...	...	@@ -304,7 +286,7 @@
304	286
305	287	highmem = 0;
306	288	iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
307		- max_physmem = get_kmem_end() - uml_physmem - iomem_size - MIN_VMALLOC;
	289	+ max_physmem = CONFIG_TOP_ADDR - uml_physmem - iomem_size - MIN_VMALLOC;
308	290
309	291	/*
310	292	* Zones have to begin on a 1 << MAX_ORDER page boundary,
...	...	@@ -336,7 +318,7 @@
336	318	}
337	319
338	320	virtmem_size = physmem_size;
339		- avail = get_kmem_end() - start_vm;
	321	+ avail = CONFIG_TOP_ADDR - start_vm;
340	322	if (physmem_size > avail)
341	323	virtmem_size = avail;
342	324	end_vm = start_vm + virtmem_size;
...	...	@@ -13,11 +13,9 @@
13	13
14	14	extern unsigned long stacksizelim;
15	15
16		-extern unsigned long host_task_size;
17		-
18	16	#define STACK_ROOM (stacksizelim)
19	17
20		-#define STACK_TOP task_size
	18	+#define STACK_TOP (TASK_SIZE - 2 * PAGE_SIZE)
21	19
22	20	#define STACK_TOP_MAX STACK_TOP
23	21
...	...	@@ -56,9 +56,8 @@
56	56	* the start of the fixmap, and leave one page empty
57	57	* at the top of mem..
58	58	*/
59		-extern unsigned long get_kmem_end(void);
60	59
61		-#define FIXADDR_TOP (get_kmem_end() - 0x2000)
	60	+#define FIXADDR_TOP (CONFIG_TOP_ADDR - 2 * PAGE_SIZE)
62	61	#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
63	62	#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
64	63