Re: [GIT PULL] Xen bugfixes

From: Jeremy Fitzhardinge
Date: Thu Sep 10 2009 - 13:16:32 EST


On 09/09/09 22:16, Ingo Molnar wrote:
>> +# Make sure __phys_addr has no stackprotector
>> +nostackp := $(call cc-option, -fno-stack-protector)
>> +CFLAGS_ioremap.o := $(nostackp)
>> +
>>
> Sure we could move __phys_addr into its own file and thus avoid
> turning off stackprotector for the rest of ioremap.c?
>

I'm not very keen on having zillions of tiny files just to cope with the
lack of per-function stackprotector disable. I don't see any code in
ioremap.c that would really benefit from stack-protector anyway; there
are no local arrays.

At least __phys_addr and friends aren't terribly closely related to
ioremap so it would at least make some sense. Patch below.

>> --- a/arch/x86/xen/Makefile
>> +++ b/arch/x86/xen/Makefile
>> @@ -8,6 +8,7 @@ endif
>> # Make sure early boot has no stackprotector
>> nostackp := $(call cc-option, -fno-stack-protector)
>> CFLAGS_enlighten.o := $(nostackp)
>> +CFLAGS_mmu.o := $(nostackp)
>>
> A similar argument could be made here - what proportion of mmu.c is
> affected?
>

More. It would be a fairly arbitrary chunk of code to split out into a
separate file.

> Also, once the commits have hit upstream feel free bounce them to
> stable@xxxxxxxxxx - they dont have Cc: <stable@xxxxxxxxxx> tags for
> automatic back-merging requests. The fixes narrowly missed v2.6.31.
>

Will do.

Thanks,
J

From: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
Subject: [PATCH] x86: split __phys_addr out into separate file

Split __phys_addr out into its own file so we can disable
-fstack-protector in a fine-grained fashion. Also it doesn't
have terribly much to do with the rest of ioremap.c.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>

diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index 72bb3a2..9b5a9f5 100644
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -1,9 +1,9 @@
obj-y := init.o init_$(BITS).o fault.o ioremap.o extable.o pageattr.o mmap.o \
- pat.o pgtable.o gup.o
+ pat.o pgtable.o physaddr.o gup.o

# Make sure __phys_addr has no stackprotector
nostackp := $(call cc-option, -fno-stack-protector)
-CFLAGS_ioremap.o := $(nostackp)
+CFLAGS_physaddr.o := $(nostackp)

obj-$(CONFIG_SMP) += tlb.o

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 8a45093..04e1ad6 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -22,77 +22,7 @@
#include <asm/pgalloc.h>
#include <asm/pat.h>

-static inline int phys_addr_valid(resource_size_t addr)
-{
-#ifdef CONFIG_PHYS_ADDR_T_64BIT
- return !(addr >> boot_cpu_data.x86_phys_bits);
-#else
- return 1;
-#endif
-}
-
-#ifdef CONFIG_X86_64
-
-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(!phys_addr_valid(x));
- }
- return x;
-}
-EXPORT_SYMBOL(__phys_addr);
-
-bool __virt_addr_valid(unsigned long x)
-{
- if (x >= __START_KERNEL_map) {
- x -= __START_KERNEL_map;
- if (x >= KERNEL_IMAGE_SIZE)
- return false;
- x += phys_base;
- } else {
- if (x < PAGE_OFFSET)
- return false;
- x -= PAGE_OFFSET;
- if (!phys_addr_valid(x))
- return false;
- }
-
- return pfn_valid(x >> PAGE_SHIFT);
-}
-EXPORT_SYMBOL(__virt_addr_valid);
-
-#else
-
-#ifdef CONFIG_DEBUG_VIRTUAL
-unsigned long __phys_addr(unsigned long x)
-{
- /* VMALLOC_* aren't constants */
- VIRTUAL_BUG_ON(x < PAGE_OFFSET);
- VIRTUAL_BUG_ON(__vmalloc_start_set && is_vmalloc_addr((void *) x));
- return x - PAGE_OFFSET;
-}
-EXPORT_SYMBOL(__phys_addr);
-#endif
-
-bool __virt_addr_valid(unsigned long x)
-{
- if (x < PAGE_OFFSET)
- return false;
- if (__vmalloc_start_set && is_vmalloc_addr((void *) x))
- return false;
- if (x >= FIXADDR_START)
- return false;
- return pfn_valid((x - PAGE_OFFSET) >> PAGE_SHIFT);
-}
-EXPORT_SYMBOL(__virt_addr_valid);
-
-#endif
+#include "physaddr.h"

int page_is_ram(unsigned long pagenr)
{
diff --git a/arch/x86/mm/physaddr.c b/arch/x86/mm/physaddr.c
new file mode 100644
index 0000000..d2e2735
--- /dev/null
+++ b/arch/x86/mm/physaddr.c
@@ -0,0 +1,70 @@
+#include <linux/mmdebug.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+
+#include <asm/page.h>
+
+#include "physaddr.h"
+
+#ifdef CONFIG_X86_64
+
+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(!phys_addr_valid(x));
+ }
+ return x;
+}
+EXPORT_SYMBOL(__phys_addr);
+
+bool __virt_addr_valid(unsigned long x)
+{
+ if (x >= __START_KERNEL_map) {
+ x -= __START_KERNEL_map;
+ if (x >= KERNEL_IMAGE_SIZE)
+ return false;
+ x += phys_base;
+ } else {
+ if (x < PAGE_OFFSET)
+ return false;
+ x -= PAGE_OFFSET;
+ if (!phys_addr_valid(x))
+ return false;
+ }
+
+ return pfn_valid(x >> PAGE_SHIFT);
+}
+EXPORT_SYMBOL(__virt_addr_valid);
+
+#else
+
+#ifdef CONFIG_DEBUG_VIRTUAL
+unsigned long __phys_addr(unsigned long x)
+{
+ /* VMALLOC_* aren't constants */
+ VIRTUAL_BUG_ON(x < PAGE_OFFSET);
+ VIRTUAL_BUG_ON(__vmalloc_start_set && is_vmalloc_addr((void *) x));
+ return x - PAGE_OFFSET;
+}
+EXPORT_SYMBOL(__phys_addr);
+#endif
+
+bool __virt_addr_valid(unsigned long x)
+{
+ if (x < PAGE_OFFSET)
+ return false;
+ if (__vmalloc_start_set && is_vmalloc_addr((void *) x))
+ return false;
+ if (x >= FIXADDR_START)
+ return false;
+ return pfn_valid((x - PAGE_OFFSET) >> PAGE_SHIFT);
+}
+EXPORT_SYMBOL(__virt_addr_valid);
+
+#endif /* CONFIG_X86_64 */
diff --git a/arch/x86/mm/physaddr.h b/arch/x86/mm/physaddr.h
new file mode 100644
index 0000000..a3cd5a0
--- /dev/null
+++ b/arch/x86/mm/physaddr.h
@@ -0,0 +1,10 @@
+#include <asm/processor.h>
+
+static inline int phys_addr_valid(resource_size_t addr)
+{
+#ifdef CONFIG_PHYS_ADDR_T_64BIT
+ return !(addr >> boot_cpu_data.x86_phys_bits);
+#else
+ return 1;
+#endif
+}


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