[PATCH 06/24] arm64: Harden is_ttbr1_addr() on tagged addresses

["Pierre-Clément Tosi" <ptosi@google.com>]

When neither CONFIG_KASAN_{SW,HW}_TAGS is enabled, the KASAN function is
a no-op, leading to the check "addr >= PAGE_OFFSET". This is inaccurate
as CONFIG_ARM64_MTE=y sets TCR_EL1.TBI1, meaning that addresses with a
non-canonical top byte would get translated through TTBR1 while failing
the check above (PAGE_OFFSET's MSB is 0xff), making is_ttbr0_addr()
wrong on those corner cases.

Remove the KASAN dependency from <asm/processor.h>, as is_ttbr1_addr()
was its sole user and include <asm/mte-kasan.h> from <asm/mte.h> to
satisfy #includes which relied on the transitive include.

Signed-off-by: Pierre-Clément Tosi <ptosi@google.com>
---
 arch/arm64/include/asm/mte.h       | 1 +
 arch/arm64/include/asm/processor.h | 6 +++---
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h
index 83f3b05fc784..1d6113ae786f 100644
--- a/arch/arm64/include/asm/mte.h
+++ b/arch/arm64/include/asm/mte.h
@@ -7,6 +7,7 @@
 
 #include <asm/compiler.h>
 #include <asm/mte-def.h>
+#include <asm/mte-kasan.h>
 
 #ifndef __ASSEMBLER__
 
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index 481f1999f7c1..510e3a3046bf 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -39,8 +39,8 @@
 #include <asm/alternative.h>
 #include <asm/cpufeature.h>
 #include <asm/hw_breakpoint.h>
-#include <asm/kasan.h>
 #include <asm/lse.h>
+#include <asm/memory.h>
 #include <asm/pgtable-hwdef.h>
 #include <asm/pointer_auth.h>
 #include <asm/ptrace.h>
@@ -366,8 +366,8 @@ static __always_inline bool is_ttbr0_addr(unsigned long addr)
 
 static __always_inline bool is_ttbr1_addr(unsigned long addr)
 {
-	/* TTBR1 addresses may have a tag if KASAN_SW_TAGS is in use */
-	return arch_kasan_reset_tag(addr) >= PAGE_OFFSET;
+	/* TTBR1 addresses may have a tag */
+	return __untagged_addr(addr) >= PAGE_OFFSET;
 }
 
 /* Forward declaration, a strange C thing */

-- 
2.56.0.455.g6c5a503b38-goog