On 07/22/2015 05:25 PM, Alexey Klimov wrote:

Hi Andrey,

Could you please check minor comments below?

On Wed, Jul 22, 2015 at 1:30 PM, Andrey Ryabinin [off-list ref] wrote:

quoted

Introduce generic kasan_populate_zero_shadow(start, end).
This function maps kasan_zero_page to the [start, end] addresses.

In follow on patches it will be used for ARMv8 (and maybe other
architectures) and will replace x86_64 specific populate_zero_shadow().

Signed-off-by: Andrey Ryabinin <redacted>
---
 arch/x86/mm/kasan_init_64.c |   8 +--
 include/linux/kasan.h       |   8 +++
 mm/kasan/Makefile           |   2 +-
 mm/kasan/kasan_init.c       | 142 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 155 insertions(+), 5 deletions(-)
 create mode 100644 mm/kasan/kasan_init.c

[..]

quoted

diff --git a/mm/kasan/kasan_init.c b/mm/kasan/kasan_init.c
new file mode 100644
index 0000000..37fb46a
--- /dev/null
+++ b/mm/kasan/kasan_init.c

@@ -0,0 +1,142 @@
+#include <linux/bootmem.h>
+#include <linux/init.h>
+#include <linux/kasan.h>
+#include <linux/kernel.h>
+#include <linux/memblock.h>
+#include <linux/pfn.h>
+
+#include <asm/page.h>
+#include <asm/pgalloc.h>
+

Are you releasing code under GPL?
Shouldn't there be any license header in such new file?

Sure, will do.

...

quoted

+
+               if (pgd_none(*pgd)) {
+                       void *p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
+                       if (!p)
+                               return -ENOMEM;
+                       pgd_populate(&init_mm, pgd, p);
+               }
+               zero_pud_populate(pgd, addr, next);

But you're not checking return value after zero_pud_populate() and
zero_pmd_populate() that might fail with ENOMEM.
Is it critical here on init or can they be converted to return void?

I think it's better to convert these functions to void.
BTW, this check after early_alloc() is pointless because early_alloc() will panic
if allocation failed.

quoted

+/**
+ * kasan_populate_zero_shadow - populate shadow memory region with
+ *                               kasan_zero_page
+ * @start - start of the memory range to populate
+ * @end   - end of the memory range to populate
+ */
+void __init kasan_populate_zero_shadow(const void *start, const void *end)
+{
+       if (zero_pgd_populate((unsigned long)start, (unsigned long)end))
+               panic("kasan: unable to map zero shadow!");
+}
--
2.4.5


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