[PATCH v4 5/7] arm64: add KASAN support
From: catalin.marinas@arm.com (Catalin Marinas)
Date: 2015-07-27 15:59:30
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linux-mm, lkml
On Fri, Jul 24, 2015 at 07:41:57PM +0300, Andrey Ryabinin wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 4d2a925..2cacf55 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile@@ -40,6 +40,12 @@ else TEXT_OFFSET := 0x00080000 endif +# KASAN_SHADOW_OFFSET = VA_START + (1 << (VA_BITS - 3)) - (1 << 61) +KASAN_SHADOW_OFFSET := $(shell printf "0x%x\n" $$(( \ + (-1 << $(CONFIG_ARM64_VA_BITS)) \ + + (1 << ($(CONFIG_ARM64_VA_BITS) - 3)) \ + - (1 << (64 - 3)) )) )
Does this work with any POSIX shell? Do we always have a 64-bit type? As I wasn't sure about this, I suggested awk (or perl).
+static void __init clear_pgds(unsigned long start,
+ unsigned long end)
+{
+ /*
+ * Remove references to kasan page tables from
+ * swapper_pg_dir. pgd_clear() can't be used
+ * here because it's nop on 2,3-level pagetable setups
+ */
+ for (; start && start < end; start += PGDIR_SIZE)
+ set_pgd(pgd_offset_k(start), __pgd(0));
+}I don't think we need the "start" check, just "start < end". Do you expect a start == 0 (or overflow)? -- Catalin