um: Remove broken highmem support

Highmem was always buggy and experimental on UML(i386).
In times where 64 bit computers are default we can
remove that experimental code.
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/Kconfig.um

@@ -95,18 +95,6 @@ config MAGIC_SYSRQ
 	  The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
 	  unless you really know what this hack does.
 
-config HIGHMEM
-	bool "Highmem support"
-	depends on !64BIT && BROKEN
-	default n
-	help
-	  This was used to allow UML to run with big amounts of memory.
-	  Currently it is unstable, so if unsure say N.
-
-	  To use big amounts of memory, it is recommended enable static
-	  linking (i.e. CONFIG_STATIC_LINK) - this should allow the
-	  guest to use up to 2.75G of memory.
-
 config KERNEL_STACK_ORDER
 	int "Kernel stack size order"
 	default 1 if 64BIT

arch/um/include/asm/fixmap.h

@@ -33,10 +33,6 @@
  * fix-mapped?
  */
 enum fixed_addresses {
-#ifdef CONFIG_HIGHMEM
-	FIX_KMAP_BEGIN,	/* reserved pte's for temporary kernel mappings */
-	FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
-#endif
 	__end_of_fixed_addresses
 };
 

arch/um/include/asm/pgtable.h

@@ -47,11 +47,7 @@ extern unsigned long end_iomem;
 #define VMALLOC_OFFSET	(__va_space)
 #define VMALLOC_START ((end_iomem + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1))
 #define PKMAP_BASE ((FIXADDR_START - LAST_PKMAP * PAGE_SIZE) & PMD_MASK)
-#ifdef CONFIG_HIGHMEM
-# define VMALLOC_END	(PKMAP_BASE-2*PAGE_SIZE)
-#else
-# define VMALLOC_END	(FIXADDR_START-2*PAGE_SIZE)
-#endif
+#define VMALLOC_END	(FIXADDR_START-2*PAGE_SIZE)
 #define MODULES_VADDR	VMALLOC_START
 #define MODULES_END	VMALLOC_END
 #define MODULES_LEN	(MODULES_VADDR - MODULES_END)

arch/um/kernel/mem.c

@@ -38,19 +38,6 @@ int kmalloc_ok = 0;
 /* Used during early boot */
 static unsigned long brk_end;
 
-#ifdef CONFIG_HIGHMEM
-static void setup_highmem(unsigned long highmem_start,
-			  unsigned long highmem_len)
-{
-	unsigned long highmem_pfn;
-	int i;
-
-	highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
-	for (i = 0; i < highmem_len >> PAGE_SHIFT; i++)
-		free_highmem_page(&mem_map[highmem_pfn + i]);
-}
-#endif
-
 void __init mem_init(void)
 {
 	/* clear the zero-page */
@@ -67,9 +54,6 @@ void __init mem_init(void)
 	/* this will put all low memory onto the freelists */
 	free_all_bootmem();
 	max_low_pfn = totalram_pages;
-#ifdef CONFIG_HIGHMEM
-	setup_highmem(end_iomem, highmem);
-#endif
 	max_pfn = totalram_pages;
 	mem_init_print_info(NULL);
 	kmalloc_ok = 1;
@@ -127,49 +111,6 @@ static void __init fixrange_init(unsigned long start, unsigned long end,
 	}
 }
 
-#ifdef CONFIG_HIGHMEM
-pte_t *kmap_pte;
-pgprot_t kmap_prot;
-
-#define kmap_get_fixmap_pte(vaddr)					\
-	pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)),\
-				     (vaddr)), (vaddr))
-
-static void __init kmap_init(void)
-{
-	unsigned long kmap_vstart;
-
-	/* cache the first kmap pte */
-	kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
-	kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
-
-	kmap_prot = PAGE_KERNEL;
-}
-
-static void __init init_highmem(void)
-{
-	pgd_t *pgd;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *pte;
-	unsigned long vaddr;
-
-	/*
-	 * Permanent kmaps:
-	 */
-	vaddr = PKMAP_BASE;
-	fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);
-
-	pgd = swapper_pg_dir + pgd_index(vaddr);
-	pud = pud_offset(pgd, vaddr);
-	pmd = pmd_offset(pud, vaddr);
-	pte = pte_offset_kernel(pmd, vaddr);
-	pkmap_page_table = pte;
-
-	kmap_init();
-}
-#endif /* CONFIG_HIGHMEM */
-
 static void __init fixaddr_user_init( void)
 {
 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
@@ -211,9 +152,6 @@ void __init paging_init(void)
 
 	zones_size[ZONE_NORMAL] = (end_iomem >> PAGE_SHIFT) -
 		(uml_physmem >> PAGE_SHIFT);
-#ifdef CONFIG_HIGHMEM
-	zones_size[ZONE_HIGHMEM] = highmem >> PAGE_SHIFT;
-#endif
 	free_area_init(zones_size);
 
 	/*
@@ -224,10 +162,6 @@ void __init paging_init(void)
 	fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
 
 	fixaddr_user_init();
-
-#ifdef CONFIG_HIGHMEM
-	init_highmem();
-#endif
 }
 
 /*

arch/um/kernel/um_arch.c

@@ -301,11 +301,6 @@ int __init linux_main(int argc, char **argv)
 	if (physmem_size + iomem_size > max_physmem) {
 		highmem = physmem_size + iomem_size - max_physmem;
 		physmem_size -= highmem;
-#ifndef CONFIG_HIGHMEM
-		highmem = 0;
-		printf("CONFIG_HIGHMEM not enabled - physical memory shrunk "
-		       "to %Lu bytes\n", physmem_size);
-#endif
 	}
 
 	high_physmem = uml_physmem + physmem_size;

arch/x86/um/Makefile

@@ -21,7 +21,6 @@ obj-$(CONFIG_BINFMT_ELF) += elfcore.o
 
 subarch-y = ../lib/string_32.o ../lib/atomic64_32.o ../lib/atomic64_cx8_32.o
 subarch-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += ../lib/rwsem.o
-subarch-$(CONFIG_HIGHMEM) += ../mm/highmem_32.o
 
 else