kernel-ark/include/asm-i386/page.h
Jeremy Fitzhardinge 1dbf527c51 [PATCH] i386: Make COMPAT_VDSO runtime selectable.
Now that relocation of the VDSO for COMPAT_VDSO users is done at
runtime rather than compile time, it is possible to enable/disable
compat mode at runtime.

This patch allows you to enable COMPAT_VDSO mode with "vdso=2" on the
kernel command line, or via sysctl.  (Switching on a running system
shouldn't be done lightly; any process which was relying on the compat
VDSO will be upset if it goes away.)

The COMPAT_VDSO config option still exists, but if enabled it just
makes vdso_enabled default to VDSO_COMPAT.

+From: Hugh Dickins <hugh@veritas.com>

Fix oops from i386-make-compat_vdso-runtime-selectable.patch.

Even mingetty at system startup finds it easy to trigger an oops
while reading /proc/PID/maps: though it has a good hold on the mm
itself, that cannot stop exit_mm() from resetting tsk->mm to NULL.

(It is usually show_map()'s call to get_gate_vma() which oopses,
and I expect we could change that to check priv->tail_vma instead;
but no matter, even m_start()'s call just after get_task_mm() is racy.)

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Zachary Amsden <zach@vmware.com>
Cc: "Jan Beulich" <JBeulich@novell.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Roland McGrath <roland@redhat.com>
2007-05-02 19:27:12 +02:00

150 lines
4.3 KiB
C

#ifndef _I386_PAGE_H
#define _I386_PAGE_H
/* PAGE_SHIFT determines the page size */
#define PAGE_SHIFT 12
#define PAGE_SIZE (1UL << PAGE_SHIFT)
#define PAGE_MASK (~(PAGE_SIZE-1))
#define LARGE_PAGE_MASK (~(LARGE_PAGE_SIZE-1))
#define LARGE_PAGE_SIZE (1UL << PMD_SHIFT)
#ifdef __KERNEL__
#ifndef __ASSEMBLY__
#ifdef CONFIG_X86_USE_3DNOW
#include <asm/mmx.h>
#define clear_page(page) mmx_clear_page((void *)(page))
#define copy_page(to,from) mmx_copy_page(to,from)
#else
/*
* On older X86 processors it's not a win to use MMX here it seems.
* Maybe the K6-III ?
*/
#define clear_page(page) memset((void *)(page), 0, PAGE_SIZE)
#define copy_page(to,from) memcpy((void *)(to), (void *)(from), PAGE_SIZE)
#endif
#define clear_user_page(page, vaddr, pg) clear_page(page)
#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
#define alloc_zeroed_user_highpage(vma, vaddr) alloc_page_vma(GFP_HIGHUSER | __GFP_ZERO, vma, vaddr)
#define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
/*
* These are used to make use of C type-checking..
*/
extern int nx_enabled;
#ifdef CONFIG_X86_PAE
extern unsigned long long __supported_pte_mask;
typedef struct { unsigned long pte_low, pte_high; } pte_t;
typedef struct { unsigned long long pmd; } pmd_t;
typedef struct { unsigned long long pgd; } pgd_t;
typedef struct { unsigned long long pgprot; } pgprot_t;
#define pmd_val(x) ((x).pmd)
#define pte_val(x) ((x).pte_low | ((unsigned long long)(x).pte_high << 32))
#define __pmd(x) ((pmd_t) { (x) } )
#define HPAGE_SHIFT 21
#include <asm-generic/pgtable-nopud.h>
#else
typedef struct { unsigned long pte_low; } pte_t;
typedef struct { unsigned long pgd; } pgd_t;
typedef struct { unsigned long pgprot; } pgprot_t;
#define boot_pte_t pte_t /* or would you rather have a typedef */
#define pte_val(x) ((x).pte_low)
#define HPAGE_SHIFT 22
#include <asm-generic/pgtable-nopmd.h>
#endif
#define PTE_MASK PAGE_MASK
#ifdef CONFIG_HUGETLB_PAGE
#define HPAGE_SIZE ((1UL) << HPAGE_SHIFT)
#define HPAGE_MASK (~(HPAGE_SIZE - 1))
#define HUGETLB_PAGE_ORDER (HPAGE_SHIFT - PAGE_SHIFT)
#define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
#endif
#define pgd_val(x) ((x).pgd)
#define pgprot_val(x) ((x).pgprot)
#define __pte(x) ((pte_t) { (x) } )
#define __pgd(x) ((pgd_t) { (x) } )
#define __pgprot(x) ((pgprot_t) { (x) } )
#endif /* !__ASSEMBLY__ */
/* to align the pointer to the (next) page boundary */
#define PAGE_ALIGN(addr) (((addr)+PAGE_SIZE-1)&PAGE_MASK)
/*
* This handles the memory map.. We could make this a config
* option, but too many people screw it up, and too few need
* it.
*
* A __PAGE_OFFSET of 0xC0000000 means that the kernel has
* a virtual address space of one gigabyte, which limits the
* amount of physical memory you can use to about 950MB.
*
* If you want more physical memory than this then see the CONFIG_HIGHMEM4G
* and CONFIG_HIGHMEM64G options in the kernel configuration.
*/
#ifndef __ASSEMBLY__
struct vm_area_struct;
/*
* This much address space is reserved for vmalloc() and iomap()
* as well as fixmap mappings.
*/
extern unsigned int __VMALLOC_RESERVE;
extern int sysctl_legacy_va_layout;
extern int page_is_ram(unsigned long pagenr);
#endif /* __ASSEMBLY__ */
#ifdef __ASSEMBLY__
#define __PAGE_OFFSET CONFIG_PAGE_OFFSET
#else
#define __PAGE_OFFSET ((unsigned long)CONFIG_PAGE_OFFSET)
#endif
#define PAGE_OFFSET ((unsigned long)__PAGE_OFFSET)
#define VMALLOC_RESERVE ((unsigned long)__VMALLOC_RESERVE)
#define MAXMEM (-__PAGE_OFFSET-__VMALLOC_RESERVE)
#define __pa(x) ((unsigned long)(x)-PAGE_OFFSET)
/* __pa_symbol should be used for C visible symbols.
This seems to be the official gcc blessed way to do such arithmetic. */
#define __pa_symbol(x) __pa(RELOC_HIDE((unsigned long)(x),0))
#define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET))
#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
#ifdef CONFIG_FLATMEM
#define pfn_valid(pfn) ((pfn) < max_mapnr)
#endif /* CONFIG_FLATMEM */
#define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
#define VM_DATA_DEFAULT_FLAGS \
(VM_READ | VM_WRITE | \
((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0 ) | \
VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
#include <asm-generic/memory_model.h>
#include <asm-generic/page.h>
#define __HAVE_ARCH_GATE_AREA 1
#endif /* __KERNEL__ */
#endif /* _I386_PAGE_H */