The patch titled
x86: make __FIXADDR_TOP variable to allow it to make space for a hypervisor
has been added to the -mm tree. Its filename is
x86-make-__fixaddr_top-variable-to-allow-it-to-make-space-for-a-hypervisor.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: x86: make __FIXADDR_TOP variable to allow it to make space for a hypervisor
From: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>
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@xxxxxxx>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>
Cc: Gerd Hoffmann <kraxel@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/i386/Kconfig | 1
arch/i386/mm/init.c | 42 ++++++++++++++++++++++++++++++++++++
arch/i386/mm/pgtable.c | 26 ++++++++++++++++++++++
include/asm-i386/fixmap.h | 7 +++++-
4 files changed, 75 insertions(+), 1 deletion(-)
diff -puN arch/i386/Kconfig~x86-make-__fixaddr_top-variable-to-allow-it-to-make-space-for-a-hypervisor arch/i386/Kconfig
--- a/arch/i386/Kconfig~x86-make-__fixaddr_top-variable-to-allow-it-to-make-space-for-a-hypervisor
+++ a/arch/i386/Kconfig
@@ -812,6 +812,7 @@ 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---
diff -puN arch/i386/mm/init.c~x86-make-__fixaddr_top-variable-to-allow-it-to-make-space-for-a-hypervisor arch/i386/mm/init.c
--- a/arch/i386/mm/init.c~x86-make-__fixaddr_top-variable-to-allow-it-to-make-space-for-a-hypervisor
+++ a/arch/i386/mm/init.c
@@ -609,6 +609,48 @@ 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!");
diff -puN arch/i386/mm/pgtable.c~x86-make-__fixaddr_top-variable-to-allow-it-to-make-space-for-a-hypervisor arch/i386/mm/pgtable.c
--- a/arch/i386/mm/pgtable.c~x86-make-__fixaddr_top-variable-to-allow-it-to-make-space-for-a-hypervisor
+++ a/arch/i386/mm/pgtable.c
@@ -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>
@@ -137,6 +138,12 @@ void set_pmd_pfn(unsigned long vaddr, un
__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);
@@ -146,6 +153,25 @@ void __set_fixmap (enum fixed_addresses
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)
diff -puN include/asm-i386/fixmap.h~x86-make-__fixaddr_top-variable-to-allow-it-to-make-space-for-a-hypervisor include/asm-i386/fixmap.h
--- a/include/asm-i386/fixmap.h~x86-make-__fixaddr_top-variable-to-allow-it-to-make-space-for-a-hypervisor
+++ a/include/asm-i386/fixmap.h
@@ -19,7 +19,11 @@
* Leave one empty page between vmalloc'ed areas and
* the start of the fixmap.
*/
-#define __FIXADDR_TOP 0xfffff000
+#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)
_
Patches currently in -mm which might be from jeremy@xxxxxxxxxxxxx are
x86-remove-locally-defined-ldt-structure-in-favour-of-standard-type.patch
x86-implement-always-locked-bit-ops-for-memory-shared-with-an-smp-hypervisor.patch
x86-allow-a-kernel-to-not-be-in-ring-0.patch
x86-replace-sensitive-instructions-with-macros.patch
x86-roll-all-the-cpuid-asm-into-one-__cpuid-call.patch
x86-make-__fixaddr_top-variable-to-allow-it-to-make-space-for-a-hypervisor.patch
x86-add-a-bootparameter-to-reserve-high-linear-address-space.patch
x86-put-note-sections-into-a-pt_note-segment-in-vmlinux.patch
-
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