powerpc: Minor cleanups of kernel virt address space definitions

Make FIXADDR_TOP a compile time constant and cleanup a couple of definitions relative to the layout of the kernel address space on ppc32. We also print out that layout at boot time for debugging purposes. This is a pre-requisite for properly fixing non-coherent DMA allocactions. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc: Minor cleanups of kernel virt address space definitions
Make FIXADDR_TOP a compile time constant and cleanup a couple of definitions relative to the layout of the kernel address space on ppc32. We also print out that layout at boot time for debugging purposes. This is a pre-requisite for properly fixing non-coherent DMA allocactions. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Benjamin Herrenschmidt
1 parent b16e7766d6
Showing 5 changed files with 37 additions and 12 deletions Side-by-side Diff
arch/powerpc/include/asm/fixmap.h
arch/powerpc/include/asm/pgtable-ppc32.h
arch/powerpc/mm/init_32.c
arch/powerpc/mm/mem.c
arch/powerpc/mm/pgtable_32.c
@@ -14,8 +14,6 @@
 #ifndef _ASM_FIXMAP_H
 #define _ASM_FIXMAP_H
  
-extern unsigned long FIXADDR_TOP;
-
 #ifndef __ASSEMBLY__
 #include <linux/kernel.h>
 #include <asm/page.h>
@@ -23,6 +21,8 @@
 #include <linux/threads.h>
 #include <asm/kmap_types.h>
 #endif
+
+#define FIXADDR_TOP	((unsigned long)(-PAGE_SIZE))
  
 /*
  * Here we define all the compile-time 'special' virtual
@@ -10,7 +10,7 @@
  
 extern unsigned long va_to_phys(unsigned long address);
 extern pte_t *va_to_pte(unsigned long address);
-extern unsigned long ioremap_bot, ioremap_base;
+extern unsigned long ioremap_bot;
  
 #ifdef CONFIG_44x
 extern int icache_44x_need_flush;
  
@@ -56,8 +56,26 @@
 	printk("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
  
 /*
+ * This is the bottom of the PKMAP area with HIGHMEM or an arbitrary
+ * value (for now) on others, from where we can start layout kernel
+ * virtual space that goes below PKMAP and FIXMAP
+ */
+#ifdef CONFIG_HIGHMEM
+#define KVIRT_TOP	PKMAP_BASE
+#else
+#define KVIRT_TOP	(0xfe000000UL)	/* for now, could be FIXMAP_BASE ? */
+#endif
+
+/*
+ * ioremap_bot starts at that address. Early ioremaps move down from there,
+ * until mem_init() at which point this becomes the top of the vmalloc
+ * and ioremap space
+ */
+#define IOREMAP_TOP	KVIRT_TOP
+
+/*
  * Just any arbitrary offset to the start of the vmalloc VM area: the
- * current 64MB value just means that there will be a 64MB "hole" after the
+ * current 16MB value just means that there will be a 64MB "hole" after the
  * physical memory until the kernel virtual memory starts.  That means that
  * any out-of-bounds memory accesses will hopefully be caught.
  * The vmalloc() routines leaves a hole of 4kB between each vmalloced
@@ -168,12 +168,8 @@
 		ppc_md.progress("MMU:mapin", 0x301);
 	mapin_ram();
  
-#ifdef CONFIG_HIGHMEM
-	ioremap_base = PKMAP_BASE;
-#else
-	ioremap_base = 0xfe000000UL;	/* for now, could be 0xfffff000 */
-#endif /* CONFIG_HIGHMEM */
-	ioremap_bot = ioremap_base;
+	/* Initialize early top-down ioremap allocator */
+	ioremap_bot = IOREMAP_TOP;
  
 	/* Map in I/O resources */
 	if (ppc_md.progress)
@@ -380,6 +380,19 @@
 		bsssize >> 10,
 		initsize >> 10);
  
+#ifdef CONFIG_PPC32
+	pr_info("Kernel virtual memory layout:\n");
+	pr_info("  * 0x%08lx..0x%08lx  : fixmap\n", FIXADDR_START, FIXADDR_TOP);
+#ifdef CONFIG_HIGHMEM
+	pr_info("  * 0x%08lx..0x%08lx  : highmem PTEs\n",
+		PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP));
+#endif /* CONFIG_HIGHMEM */
+	pr_info("  * 0x%08lx..0x%08lx  : early ioremap\n",
+		ioremap_bot, IOREMAP_TOP);
+	pr_info("  * 0x%08lx..0x%08lx  : vmalloc & ioremap\n",
+		VMALLOC_START, VMALLOC_END);
+#endif /* CONFIG_PPC32 */
+
 	mem_init_done = 1;
 }
  
@@ -399,8 +399,6 @@
 #endif /* CONFIG_DEBUG_PAGEALLOC */
  
 static int fixmaps;
-unsigned long FIXADDR_TOP = (-PAGE_SIZE);
-EXPORT_SYMBOL(FIXADDR_TOP);
  
 void __set_fixmap (enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
 {
...	...	@@ -14,8 +14,6 @@
14	14	#ifndef _ASM_FIXMAP_H
15	15	#define _ASM_FIXMAP_H
16	16
17		-extern unsigned long FIXADDR_TOP;
18		-
19	17	#ifndef __ASSEMBLY__
20	18	#include <linux/kernel.h>
21	19	#include <asm/page.h>
...	...	@@ -23,6 +21,8 @@
23	21	#include <linux/threads.h>
24	22	#include <asm/kmap_types.h>
25	23	#endif
	24	+
	25	+#define FIXADDR_TOP ((unsigned long)(-PAGE_SIZE))
26	26
27	27	/*
28	28	* Here we define all the compile-time 'special' virtual
...	...	@@ -10,7 +10,7 @@
10	10
11	11	extern unsigned long va_to_phys(unsigned long address);
12	12	extern pte_t *va_to_pte(unsigned long address);
13		-extern unsigned long ioremap_bot, ioremap_base;
	13	+extern unsigned long ioremap_bot;
14	14
15	15	#ifdef CONFIG_44x
16	16	extern int icache_44x_need_flush;
17	17
...	...	@@ -56,8 +56,26 @@
56	56	printk("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
57	57
58	58	/*
	59	+ * This is the bottom of the PKMAP area with HIGHMEM or an arbitrary
	60	+ * value (for now) on others, from where we can start layout kernel
	61	+ * virtual space that goes below PKMAP and FIXMAP
	62	+ */
	63	+#ifdef CONFIG_HIGHMEM
	64	+#define KVIRT_TOP PKMAP_BASE
	65	+#else
	66	+#define KVIRT_TOP (0xfe000000UL) /* for now, could be FIXMAP_BASE ? */
	67	+#endif
	68	+
	69	+/*
	70	+ * ioremap_bot starts at that address. Early ioremaps move down from there,
	71	+ * until mem_init() at which point this becomes the top of the vmalloc
	72	+ * and ioremap space
	73	+ */
	74	+#define IOREMAP_TOP KVIRT_TOP
	75	+
	76	+/*
59	77	* Just any arbitrary offset to the start of the vmalloc VM area: the
60		- * current 64MB value just means that there will be a 64MB "hole" after the
	78	+ * current 16MB value just means that there will be a 64MB "hole" after the
61	79	* physical memory until the kernel virtual memory starts. That means that
62	80	* any out-of-bounds memory accesses will hopefully be caught.
63	81	* The vmalloc() routines leaves a hole of 4kB between each vmalloced
...	...	@@ -168,12 +168,8 @@
168	168	ppc_md.progress("MMU:mapin", 0x301);
169	169	mapin_ram();
170	170
171		-#ifdef CONFIG_HIGHMEM
172		- ioremap_base = PKMAP_BASE;
173		-#else
174		- ioremap_base = 0xfe000000UL; /* for now, could be 0xfffff000 */
175		-#endif /* CONFIG_HIGHMEM */
176		- ioremap_bot = ioremap_base;
	171	+ /* Initialize early top-down ioremap allocator */
	172	+ ioremap_bot = IOREMAP_TOP;
177	173
178	174	/* Map in I/O resources */
179	175	if (ppc_md.progress)
...	...	@@ -380,6 +380,19 @@
380	380	bsssize >> 10,
381	381	initsize >> 10);
382	382
	383	+#ifdef CONFIG_PPC32
	384	+ pr_info("Kernel virtual memory layout:\n");
	385	+ pr_info(" * 0x%08lx..0x%08lx : fixmap\n", FIXADDR_START, FIXADDR_TOP);
	386	+#ifdef CONFIG_HIGHMEM
	387	+ pr_info(" * 0x%08lx..0x%08lx : highmem PTEs\n",
	388	+ PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP));
	389	+#endif /* CONFIG_HIGHMEM */
	390	+ pr_info(" * 0x%08lx..0x%08lx : early ioremap\n",
	391	+ ioremap_bot, IOREMAP_TOP);
	392	+ pr_info(" * 0x%08lx..0x%08lx : vmalloc & ioremap\n",
	393	+ VMALLOC_START, VMALLOC_END);
	394	+#endif /* CONFIG_PPC32 */
	395	+
383	396	mem_init_done = 1;
384	397	}
385	398
...	...	@@ -399,8 +399,6 @@
399	399	#endif /* CONFIG_DEBUG_PAGEALLOC */
400	400
401	401	static int fixmaps;
402		-unsigned long FIXADDR_TOP = (-PAGE_SIZE);
403		-EXPORT_SYMBOL(FIXADDR_TOP);
404	402
405	403	void __set_fixmap (enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
406	404	{