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Commit 052e7994 authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Linus Torvalds
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[PATCH] x86: make __FIXADDR_TOP variable to allow it to make space for a hypervisor 



Make __FIXADDR_TOP a variable, so that it can be set to not get in the way of
address space a hypervisor may want to reserve.

Original patch by Gerd Hoffmann <kraxel@suse.de>

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: default avatarChris Wright <chrisw@sous-sol.org>
Cc: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 9f093394

arch/i386/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -794,6 +794,7 @@ config HOTPLUG_CPU 
config COMPAT_VDSO

	bool "Compat VDSO support"

	default y

	depends on !PARAVIRT

	help

	  Map the VDSO to the predictable old-style address too.

	---help---

arch/i386/mm/init.c

+42 −0
Original line number Diff line number Diff line
@@ -629,6 +629,48 @@ void __init mem_init(void) 
		(unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))

	       );



#if 1 /* double-sanity-check paranoia */

	printk("virtual kernel memory layout:\n"

	       "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"

#ifdef CONFIG_HIGHMEM

	       "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"

#endif

	       "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"

	       "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"

	       "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"

	       "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"

	       "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",

	       FIXADDR_START, FIXADDR_TOP,

	       (FIXADDR_TOP - FIXADDR_START) >> 10,



#ifdef CONFIG_HIGHMEM

	       PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,

	       (LAST_PKMAP*PAGE_SIZE) >> 10,

#endif



	       VMALLOC_START, VMALLOC_END,

	       (VMALLOC_END - VMALLOC_START) >> 20,



	       (unsigned long)__va(0), (unsigned long)high_memory,

	       ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,



	       (unsigned long)&__init_begin, (unsigned long)&__init_end,

	       ((unsigned long)&__init_end - (unsigned long)&__init_begin) >> 10,



	       (unsigned long)&_etext, (unsigned long)&_edata,

	       ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,



	       (unsigned long)&_text, (unsigned long)&_etext,

	       ((unsigned long)&_etext - (unsigned long)&_text) >> 10);



#ifdef CONFIG_HIGHMEM

	BUG_ON(PKMAP_BASE+LAST_PKMAP*PAGE_SIZE > FIXADDR_START);

	BUG_ON(VMALLOC_END                     > PKMAP_BASE);

#endif

	BUG_ON(VMALLOC_START                   > VMALLOC_END);

	BUG_ON((unsigned long)high_memory      > VMALLOC_START);

#endif /* double-sanity-check paranoia */



#ifdef CONFIG_X86_PAE

	if (!cpu_has_pae)

		panic("cannot execute a PAE-enabled kernel on a PAE-less CPU!");

arch/i386/mm/pgtable.c

+26 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/slab.h>

#include <linux/pagemap.h>

#include <linux/spinlock.h>

#include <linux/module.h>



#include <asm/system.h>

#include <asm/pgtable.h>
@@ -139,6 +140,12 @@ void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags) 
	__flush_tlb_one(vaddr);

}



static int fixmaps;

#ifndef CONFIG_COMPAT_VDSO

unsigned long __FIXADDR_TOP = 0xfffff000;

EXPORT_SYMBOL(__FIXADDR_TOP);

#endif



void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags)

{

	unsigned long address = __fix_to_virt(idx);
@@ -148,6 +155,25 @@ void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags) 
		return;

	}

	set_pte_pfn(address, phys >> PAGE_SHIFT, flags);

	fixmaps++;

}



/**

 * reserve_top_address - reserves a hole in the top of kernel address space

 * @reserve - size of hole to reserve

 *

 * Can be used to relocate the fixmap area and poke a hole in the top

 * of kernel address space to make room for a hypervisor.

 */

void reserve_top_address(unsigned long reserve)

{

	BUG_ON(fixmaps > 0);

#ifdef CONFIG_COMPAT_VDSO

	BUG_ON(reserve != 0);

#else

	__FIXADDR_TOP = -reserve - PAGE_SIZE;

	__VMALLOC_RESERVE += reserve;

#endif

}



pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)

include/asm-i386/fixmap.h

+6 −1
Original line number Diff line number Diff line
@@ -19,7 +19,11 @@ 
 * Leave one empty page between vmalloc'ed areas and

 * the start of the fixmap.

 */

#ifndef CONFIG_COMPAT_VDSO

extern unsigned long __FIXADDR_TOP;

#else

#define __FIXADDR_TOP  0xfffff000

#endif



#ifndef __ASSEMBLY__

#include <linux/kernel.h>
@@ -93,6 +97,7 @@ enum fixed_addresses { 


extern void __set_fixmap (enum fixed_addresses idx,

					unsigned long phys, pgprot_t flags);

extern void reserve_top_address(unsigned long reserve);



#define set_fixmap(idx, phys) \

		__set_fixmap(idx, phys, PAGE_KERNEL)