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From: Samuel Holland <samuel.holland@sifive.com>
To: Palmer Dabbelt <palmer@dabbelt.com>,
	linux-riscv@lists.infradead.org,
	Andrey Ryabinin <ryabinin.a.a@gmail.com>,
	Alexander Potapenko <glider@google.com>,
	Andrey Konovalov <andreyknvl@gmail.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	kasan-dev@googlegroups.com
Cc: llvm@lists.linux.dev, Catalin Marinas <catalin.marinas@arm.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Alexandre Ghiti <alexghiti@rivosinc.com>,
	Will Deacon <will@kernel.org>,
	Evgenii Stepanov <eugenis@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-arm-kernel@lists.infradead.org,
	Samuel Holland <samuel.holland@sifive.com>
Subject: [PATCH v2 4/9] kasan: sw_tags: Support tag widths less than 8 bits
Date: Mon, 21 Oct 2024 18:57:12 -0700	[thread overview]
Message-ID: <20241022015913.3524425-5-samuel.holland@sifive.com> (raw)
In-Reply-To: <20241022015913.3524425-1-samuel.holland@sifive.com>

Allow architectures to override KASAN_TAG_KERNEL in asm/kasan.h. This
is needed on RISC-V, which supports 57-bit virtual addresses and 7-bit
pointer tags. For consistency, move the arm64 MTE definition of
KASAN_TAG_MIN to asm/kasan.h, since it is also architecture-dependent;
RISC-V's equivalent extension is expected to support 7-bit hardware
memory tags.

Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---

(no changes since v1)

 arch/arm64/include/asm/kasan.h   |  6 ++++--
 arch/arm64/include/asm/uaccess.h |  1 +
 include/linux/kasan-tags.h       | 13 ++++++++-----
 3 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/include/asm/kasan.h b/arch/arm64/include/asm/kasan.h
index e1b57c13f8a4..4ab419df8b93 100644
--- a/arch/arm64/include/asm/kasan.h
+++ b/arch/arm64/include/asm/kasan.h
@@ -6,8 +6,10 @@
 
 #include <linux/linkage.h>
 #include <asm/memory.h>
-#include <asm/mte-kasan.h>
-#include <asm/pgtable-types.h>
+
+#ifdef CONFIG_KASAN_HW_TAGS
+#define KASAN_TAG_MIN			0xF0 /* minimum value for random tags */
+#endif
 
 #define arch_kasan_set_tag(addr, tag)	__tag_set(addr, tag)
 #define arch_kasan_reset_tag(addr)	__tag_reset(addr)
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index 1aa4ecb73429..8f700a7dd2cd 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -22,6 +22,7 @@
 #include <asm/cpufeature.h>
 #include <asm/mmu.h>
 #include <asm/mte.h>
+#include <asm/mte-kasan.h>
 #include <asm/ptrace.h>
 #include <asm/memory.h>
 #include <asm/extable.h>
diff --git a/include/linux/kasan-tags.h b/include/linux/kasan-tags.h
index 4f85f562512c..e07c896f95d3 100644
--- a/include/linux/kasan-tags.h
+++ b/include/linux/kasan-tags.h
@@ -2,13 +2,16 @@
 #ifndef _LINUX_KASAN_TAGS_H
 #define _LINUX_KASAN_TAGS_H
 
+#include <asm/kasan.h>
+
+#ifndef KASAN_TAG_KERNEL
 #define KASAN_TAG_KERNEL	0xFF /* native kernel pointers tag */
-#define KASAN_TAG_INVALID	0xFE /* inaccessible memory tag */
-#define KASAN_TAG_MAX		0xFD /* maximum value for random tags */
+#endif
+
+#define KASAN_TAG_INVALID	(KASAN_TAG_KERNEL - 1) /* inaccessible memory tag */
+#define KASAN_TAG_MAX		(KASAN_TAG_KERNEL - 2) /* maximum value for random tags */
 
-#ifdef CONFIG_KASAN_HW_TAGS
-#define KASAN_TAG_MIN		0xF0 /* minimum value for random tags */
-#else
+#ifndef KASAN_TAG_MIN
 #define KASAN_TAG_MIN		0x00 /* minimum value for random tags */
 #endif
 
-- 
2.45.1



  parent reply	other threads:[~2024-10-22  1:59 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-22  1:57 [PATCH v2 0/9] kasan: RISC-V support for KASAN_SW_TAGS using pointer masking Samuel Holland
2024-10-22  1:57 ` [PATCH v2 1/9] kasan: sw_tags: Use arithmetic shift for shadow computation Samuel Holland
2024-10-23 18:41   ` Andrey Konovalov
2025-02-10 15:22     ` Maciej Wieczor-Retman
2025-02-10 15:52       ` Maciej Wieczor-Retman
2025-02-10 22:57         ` Andrey Konovalov
2025-02-11  8:58           ` Maciej Wieczor-Retman
2025-02-11 13:42             ` Maciej Wieczor-Retman
2025-02-11 18:06           ` Maciej Wieczor-Retman
2025-02-13  1:21             ` Andrey Konovalov
2025-02-13  1:28               ` Andrey Konovalov
2025-02-13 16:20                 ` Maciej Wieczor-Retman
2025-02-14  8:20                   ` Maciej Wieczor-Retman
2025-02-17 16:13                     ` Andrey Konovalov
2025-02-17 18:37                       ` Maciej Wieczor-Retman
2025-02-17 19:00                         ` Andrey Konovalov
2024-10-22  1:57 ` [PATCH v2 2/9] kasan: sw_tags: Check kasan_flag_enabled at runtime Samuel Holland
2024-10-22  1:57 ` [PATCH v2 3/9] kasan: sw_tags: Support outline stack tag generation Samuel Holland
2024-10-23 18:42   ` Andrey Konovalov
2024-10-22  1:57 ` Samuel Holland [this message]
2024-10-22 19:30   ` [PATCH v2 4/9] kasan: sw_tags: Support tag widths less than 8 bits kernel test robot
2024-10-22 19:51   ` kernel test robot
2024-10-22  1:57 ` [PATCH v2 5/9] riscv: mm: Log potential KASAN shadow alias Samuel Holland
2024-11-05 13:44   ` Alexandre Ghiti
2024-10-22  1:57 ` [PATCH v2 6/9] riscv: Do not rely on KASAN to define the memory layout Samuel Holland
2024-11-05 13:47   ` Alexandre Ghiti
2024-10-22  1:57 ` [PATCH v2 7/9] riscv: Align the sv39 linear map to 16 GiB Samuel Holland
2024-11-05 13:55   ` Alexandre Ghiti
2024-10-22  1:57 ` [PATCH v2 8/9] riscv: Add SBI Firmware Features extension definitions Samuel Holland
2024-10-22  1:57 ` [PATCH v2 9/9] riscv: Implement KASAN_SW_TAGS Samuel Holland
2024-10-23 18:42   ` Andrey Konovalov
2025-05-28  5:38 ` [PATCH v2 0/9] kasan: RISC-V support for KASAN_SW_TAGS using pointer masking JiaJie Ho

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