x86: add early_memremap()

early_ioremap() is also used to map normal memory when constructing
the linear memory mapping.  However, since we sometimes need to be able
to distinguish between actual IO mappings and normal memory mappings,
add a early_memremap() call, which maps with PAGE_KERNEL (as opposed
to PAGE_KERNEL_IO for early_ioremap()), and use it when constructing
pagetables.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/mm/init_64.c

@@ -313,7 +313,7 @@ static __ref void *alloc_low_page(unsigned long *phys)
 	if (pfn >= table_top)
 		panic("alloc_low_page: ran out of memory");
 
-	adr = early_ioremap(pfn * PAGE_SIZE, PAGE_SIZE);
+	adr = early_memremap(pfn * PAGE_SIZE, PAGE_SIZE);
 	memset(adr, 0, PAGE_SIZE);
 	*phys  = pfn * PAGE_SIZE;
 	return adr;

arch/x86/mm/ioremap.c

@@ -568,12 +568,12 @@ static void __init __early_set_fixmap(enum fixed_addresses idx,
 }
 
 static inline void __init early_set_fixmap(enum fixed_addresses idx,
-					unsigned long phys)
+					   unsigned long phys, pgprot_t prot)
 {
 	if (after_paging_init)
-		set_fixmap(idx, phys);
+		__set_fixmap(idx, phys, prot);
 	else
-		__early_set_fixmap(idx, phys, PAGE_KERNEL);
+		__early_set_fixmap(idx, phys, prot);
 }
 
 static inline void __init early_clear_fixmap(enum fixed_addresses idx)
@@ -601,7 +601,7 @@ static int __init check_early_ioremap_leak(void)
 }
 late_initcall(check_early_ioremap_leak);
 
-void __init *early_ioremap(unsigned long phys_addr, unsigned long size)
+static void __init *__early_ioremap(unsigned long phys_addr, unsigned long size, pgprot_t prot)
 {
 	unsigned long offset, last_addr;
 	unsigned int nrpages, nesting;
@@ -650,7 +650,7 @@ void __init *early_ioremap(unsigned long phys_addr, unsigned long size)
 	idx0 = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
 	idx = idx0;
 	while (nrpages > 0) {
-		early_set_fixmap(idx, phys_addr);
+		early_set_fixmap(idx, phys_addr, prot);
 		phys_addr += PAGE_SIZE;
 		--idx;
 		--nrpages;
@@ -661,6 +661,18 @@ void __init *early_ioremap(unsigned long phys_addr, unsigned long size)
 	return (void *) (offset + fix_to_virt(idx0));
 }
 
+/* Remap an IO device */
+void __init *early_ioremap(unsigned long phys_addr, unsigned long size)
+{
+	return __early_ioremap(phys_addr, size, PAGE_KERNEL_IO);
+}
+
+/* Remap memory */
+void __init *early_memremap(unsigned long phys_addr, unsigned long size)
+{
+	return __early_ioremap(phys_addr, size, PAGE_KERNEL);
+}
+
 void __init early_iounmap(void *addr, unsigned long size)
 {
 	unsigned long virt_addr;

include/asm-x86/io.h

@@ -83,6 +83,7 @@ extern void early_ioremap_init(void);
 extern void early_ioremap_clear(void);
 extern void early_ioremap_reset(void);
 extern void *early_ioremap(unsigned long offset, unsigned long size);
+extern void *early_memremap(unsigned long offset, unsigned long size);
 extern void early_iounmap(void *addr, unsigned long size);
 extern void __iomem *fix_ioremap(unsigned idx, unsigned long phys);