[PATCH v2] MM: virtual address debug
From: Jiri Slaby
Date: Wed Jun 18 2008 - 14:43:06 EST
I've removed the test from phys_to_nid and made a function from __phys_addr
only when the debugging is enabled (on x86_32).
--
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 (on DEBUG_VIRTUAL) 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 (x86_32)
- remove "(addr >> memnode_shift) >= memnodemapsize" test from phys_to_nid
since the memnodemapsize is not available on non-fake numas
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@xxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
---
arch/x86/kernel/doublefault_32.c | 2 +-
arch/x86/mm/ioremap.c | 33 ++++++++++++++++++++++++++-------
include/asm-x86/mmzone_64.h | 3 +--
include/asm-x86/page_32.h | 5 +++++
include/linux/mm.h | 7 +------
include/linux/mmdebug.h | 18 ++++++++++++++++++
lib/Kconfig.debug | 9 +++++++++
mm/vmalloc.c | 5 +++++
8 files changed, 66 insertions(+), 16 deletions(-)
create mode 100644 include/linux/mmdebug.h
diff --git a/arch/x86/kernel/doublefault_32.c b/arch/x86/kernel/doublefault_32.c
index a47798b..395acb1 100644
--- a/arch/x86/kernel/doublefault_32.c
+++ b/arch/x86/kernel/doublefault_32.c
@@ -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)
}
};
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index c0d4958..f673121 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -24,18 +24,26 @@
#ifdef CONFIG_X86_64
-unsigned long __phys_addr(unsigned long x)
+static inline int phys_addr_valid(unsigned long addr)
{
- if (x >= __START_KERNEL_map)
- return x - __START_KERNEL_map + phys_base;
- return x - PAGE_OFFSET;
+ return addr < (1UL << boot_cpu_data.x86_phys_bits);
}
-EXPORT_SYMBOL(__phys_addr);
-static inline int phys_addr_valid(unsigned long addr)
+unsigned long __phys_addr(unsigned long x)
{
- return addr < (1UL << boot_cpu_data.x86_phys_bits);
+ 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
@@ -44,6 +52,17 @@ static inline int phys_addr_valid(unsigned long addr)
return 1;
}
+#ifdef CONFIG_DEBUG_VIRTUAL
+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
+
#endif
int page_is_ram(unsigned long pagenr)
diff --git a/include/asm-x86/mmzone_64.h b/include/asm-x86/mmzone_64.h
index 594bd0d..5e3a6cb 100644
--- a/include/asm-x86/mmzone_64.h
+++ b/include/asm-x86/mmzone_64.h
@@ -7,7 +7,7 @@
#ifdef CONFIG_NUMA
-#define VIRTUAL_BUG_ON(x)
+#include <linux/mmdebug.h>
#include <asm/smp.h>
@@ -29,7 +29,6 @@ static inline __attribute__((pure)) int phys_to_nid(unsigned long addr)
{
unsigned nid;
VIRTUAL_BUG_ON(!memnodemap);
- VIRTUAL_BUG_ON((addr >> memnode_shift) >= memnodemapsize);
nid = memnodemap[addr >> memnode_shift];
VIRTUAL_BUG_ON(nid >= MAX_NUMNODES || !node_data[nid]);
return nid;
diff --git a/include/asm-x86/page_32.h b/include/asm-x86/page_32.h
index 50b33eb..4510f21 100644
--- a/include/asm-x86/page_32.h
+++ b/include/asm-x86/page_32.h
@@ -72,7 +72,12 @@ typedef struct page *pgtable_t;
#endif
#ifndef __ASSEMBLY__
+#define __phys_addr_const(x) ((x) - PAGE_OFFSET)
+#ifdef CONFIG_DEBUG_VIRTUAL
+extern unsigned long __phys_addr(unsigned long);
+#else
#define __phys_addr(x) ((x) - PAGE_OFFSET)
+#endif
#define __phys_reloc_hide(x) RELOC_HIDE((x), 0)
#ifdef CONFIG_FLATMEM
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 460128d..b898b49 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -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>
@@ -220,12 +221,6 @@ 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.
*
diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
new file mode 100644
index 0000000..860ed1a
--- /dev/null
+++ b/include/linux/mmdebug.h
@@ -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
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index f9f210d..5f15fb8 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -470,6 +470,15 @@ 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
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 35f2938..cba7d27 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -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)) {
--
1.5.5.1
--
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