Re: [PATCH v2 14/14] x86: Make software tag-based kasan available

Signed-off-by: Maciej Wieczor-Retman <redacted>
---
Changelog v2:
- Remove KASAN dense code.

 arch/x86/Kconfig                | 6 ++++++
 arch/x86/boot/compressed/misc.h | 1 +
 arch/x86/include/asm/kasan.h    | 2 +-
 arch/x86/kernel/setup.c         | 2 ++
 4 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index f4ef64bf824a..dc48eb5b664f 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig

@@ -195,6 +195,7 @@ config X86
        select HAVE_ARCH_JUMP_LABEL_RELATIVE
        select HAVE_ARCH_KASAN                  if X86_64
        select HAVE_ARCH_KASAN_VMALLOC          if X86_64
+       select HAVE_ARCH_KASAN_SW_TAGS          if ADDRESS_MASKING
        select HAVE_ARCH_KFENCE
        select HAVE_ARCH_KMSAN                  if X86_64
        select HAVE_ARCH_KGDB

@@ -402,6 +403,11 @@ config KASAN_SHADOW_OFFSET
        hex
        default 0xdffffc0000000000 if KASAN_GENERIC

+config KASAN_SHADOW_SCALE_SHIFT
+       int
+       default 4 if KASAN_SW_TAGS
+       default 3

+
 config HAVE_INTEL_TXT
        def_bool y
        depends on INTEL_IOMMU && ACPI

diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index dd8d1a85f671..f6a87e9ad200 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h

@@ -13,6 +13,7 @@
 #undef CONFIG_PARAVIRT_SPINLOCKS
 #undef CONFIG_KASAN
 #undef CONFIG_KASAN_GENERIC
+#undef CONFIG_KASAN_SW_TAGS

 #define __NO_FORTIFY

diff --git a/arch/x86/include/asm/kasan.h b/arch/x86/include/asm/kasan.h
index 4bfd3641af84..cfc31e4a2f70 100644
--- a/arch/x86/include/asm/kasan.h
+++ b/arch/x86/include/asm/kasan.h

@@ -6,7 +6,7 @@
 #include <linux/kasan-tags.h>
 #include <linux/types.h>

-#define KASAN_SHADOW_SCALE_SHIFT 3
+#define KASAN_SHADOW_SCALE_SHIFT CONFIG_KASAN_SHADOW_SCALE_SHIFT

 /*
  * Compiler uses shadow offset assuming that addresses start

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index cebee310e200..768990c573ea 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c

@@ -1124,6 +1124,8 @@ void __init setup_arch(char **cmdline_p)

        kasan_init();

+       kasan_init_sw_tags();
+
        /*
         * Sync back kernel address range.
         *
--

2.47.1