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MM: virtual address debug

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Add some (configurable) expensive sanity checking to catch wrong address
translations on x86.

- create linux/mmdebug.h file to be able include this file in
  asm headers to not get unsolvable loops in header files
- __phys_addr on x86_32 became a function in ioremap.c since
  PAGE_OFFSET, is_vmalloc_addr and VMALLOC_* non-constasts are undefined
  if declared in page_32.h
- add __phys_addr_const for initializing doublefault_tss.__cr3

Tested on 386, 386pae, x86_64 and x86_64 numa=fake=2.

Contains Andi's enable numa virtual address debug patch.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Jiri Slaby 2008-06-12 13:56:40 +02:00 committed by Ingo Molnar
parent 952f4a0a9b
commit 59ea746337
8 changed files with 62 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/kernel/doublefault_32.c
View File

@ -66,6 +66,6 @@ struct tss_struct doublefault_tss __cacheline_aligned = {
.ds = __USER_DS,
.fs = __KERNEL_PERCPU,
.__cr3 = __pa(swapper_pg_dir)
.__cr3 = __phys_addr_const((unsigned long)swapper_pg_dir)
}
};

33
arch/x86/mm/ioremap.c
View File

@ -23,19 +23,27 @@
#ifdef CONFIG_X86_64
unsigned long __phys_addr(unsigned long x)
{
if (x >= __START_KERNEL_map)
return x - __START_KERNEL_map + phys_base;
return x - PAGE_OFFSET;
}
EXPORT_SYMBOL(__phys_addr);
static inline int phys_addr_valid(unsigned long addr)
{
return addr < (1UL << boot_cpu_data.x86_phys_bits);
}
unsigned long __phys_addr(unsigned long x)
{
if (x >= __START_KERNEL_map) {
x -= __START_KERNEL_map;
VIRTUAL_BUG_ON(x >= KERNEL_IMAGE_SIZE);
x += phys_base;
} else {
VIRTUAL_BUG_ON(x < PAGE_OFFSET);
x -= PAGE_OFFSET;
VIRTUAL_BUG_ON(system_state == SYSTEM_BOOTING ? x > MAXMEM :
!phys_addr_valid(x));
}
return x;
}
EXPORT_SYMBOL(__phys_addr);
#else
static inline int phys_addr_valid(unsigned long addr)
@ -43,6 +51,15 @@ static inline int phys_addr_valid(unsigned long addr)
return 1;
}
unsigned long __phys_addr(unsigned long x)
{
/* VMALLOC_* aren't constants; not available at the boot time */
VIRTUAL_BUG_ON(x < PAGE_OFFSET || (system_state != SYSTEM_BOOTING &&
is_vmalloc_addr((void *)x)));
return x - PAGE_OFFSET;
}
EXPORT_SYMBOL(__phys_addr);
#endif
int page_is_ram(unsigned long pagenr)

2
include/asm-x86/mmzone_64.h
View File

@ -7,7 +7,7 @@
#ifdef CONFIG_NUMA
#define VIRTUAL_BUG_ON(x)
#include <linux/mmdebug.h>
#include <asm/smp.h>

3
include/asm-x86/page_32.h
View File

@ -64,7 +64,8 @@ typedef struct page *pgtable_t;
#endif
#ifndef __ASSEMBLY__
#define __phys_addr(x) ((x) - PAGE_OFFSET)
#define __phys_addr_const(x) ((x) - PAGE_OFFSET)
extern unsigned long __phys_addr(unsigned long);
#define __phys_reloc_hide(x) RELOC_HIDE((x), 0)
#ifdef CONFIG_FLATMEM

7
include/linux/mm.h
View File

@ -7,6 +7,7 @@
#include <linux/gfp.h>
#include <linux/list.h>
#include <linux/mmdebug.h>
#include <linux/mmzone.h>
#include <linux/rbtree.h>
#include <linux/prio_tree.h>
@ -210,12 +211,6 @@ struct inode;
*/
#include <linux/page-flags.h>
#ifdef CONFIG_DEBUG_VM
#define VM_BUG_ON(cond) BUG_ON(cond)
#else
#define VM_BUG_ON(condition) do { } while(0)
#endif
/*
* Methods to modify the page usage count.
*

18
include/linux/mmdebug.h Normal file
View File

@ -0,0 +1,18 @@
#ifndef LINUX_MM_DEBUG_H
#define LINUX_MM_DEBUG_H 1
#include <linux/autoconf.h>
#ifdef CONFIG_DEBUG_VM
#define VM_BUG_ON(cond) BUG_ON(cond)
#else
#define VM_BUG_ON(cond) do { } while(0)
#endif
#ifdef CONFIG_DEBUG_VIRTUAL
#define VIRTUAL_BUG_ON(cond) BUG_ON(cond)
#else
#define VIRTUAL_BUG_ON(cond) do { } while(0)
#endif
#endif

9
lib/Kconfig.debug
View File

@ -469,6 +469,15 @@ config DEBUG_VM
If unsure, say N.
config DEBUG_VIRTUAL
bool "Debug VM translations"
depends on DEBUG_KERNEL && X86
help
Enable some costly sanity checks in virtual to page code. This can
catch mistakes with virt_to_page() and friends.
If unsure, say N.
config DEBUG_WRITECOUNT
bool "Debug filesystem writers count"
depends on DEBUG_KERNEL

5
mm/vmalloc.c
View File

@ -180,6 +180,11 @@ struct page *vmalloc_to_page(const void *vmalloc_addr)
pmd_t *pmd;
pte_t *ptep, pte;
/* XXX we might need to change this if we add VIRTUAL_BUG_ON for
* architectures that do not vmalloc module space */
VIRTUAL_BUG_ON(!is_vmalloc_addr(vmalloc_addr) &&
!is_module_address(addr));
if (!pgd_none(*pgd)) {
pud = pud_offset(pgd, addr);
if (!pud_none(*pud)) {