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d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=8e63GTlhB9QbGsFBUU3MJ45Yhzqtwy6A04ZDFy/2ryA=; b=MsDR4fVzmkDCR0/x2FKgpMdwAvUcmJOTLx9a1+/NSnHvBTaHm7iZQvFOtoaapMmnK8 if9GBOpHjssTSURLF+3hs6sPKi4v9ypf+dDExIbODMsFWow+PQpVjgYBWHYczqwAAUV2 P0viSRn84AZye5ro+eIu3Znkv9J3FYQYogGNwKeO3hEOAFvx/zAw7V4sF+rNzXRzezo2 JuBzb+1QHVFXypCdq0PMaPyX7CvhueRQXXVCYZtOPbokT4al2iIGYJx5WfWQPiT4CHVS +XkBPEmIgbet9sbuUvH+DD+vI33iX/gD76Sbrf8uk5DIUhnr7ZcZkcitl5E8czfV4J2S 7x4g== X-Gm-Message-State: AOAM531uinNP34XMOk35vs5AwMSJ1hLdHQKJ65PV+/WyxYE456VVSdoT sXSkS9vgyli2T49UAi/X/Re8jWVTNbskzHDF X-Google-Smtp-Source: ABdhPJx+23yuZaLzkgw5W5iy7I2YfVUY21RAjIgQeF58w7+TG79ouc+OTfbSq4R+OK8ML2DJf7vqrB1A2M3VnTGm X-Received: from andreyknvl3.muc.corp.google.com ([2a00:79e0:15:13:7220:84ff:fe09:7e9d]) (user=andreyknvl job=sendgmr) by 2002:a5d:618c:: with SMTP id j12mr1465350wru.182.1606162165477; Mon, 23 Nov 2020 12:09:25 -0800 (PST) Date: Mon, 23 Nov 2020 21:07:49 +0100 In-Reply-To: Message-Id: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.29.2.454.gaff20da3a2-goog Subject: [PATCH mm v11 25/42] arm64: mte: Add in-kernel MTE helpers From: Andrey Konovalov To: Andrew Morton Cc: Catalin Marinas , Will Deacon , Vincenzo Frascino , Dmitry Vyukov , Andrey Ryabinin , Alexander Potapenko , Marco Elver , Evgenii Stepanov , Branislav Rankov , Kevin Brodsky , kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Konovalov X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Vincenzo Frascino Provide helper functions to manipulate allocation and pointer tags for kernel addresses. Low-level helper functions (mte_assign_*, written in assembly) operate tag values from the [0x0, 0xF] range. High-level helper functions (mte_get/set_*) use the [0xF0, 0xFF] range to preserve compatibility with normal kernel pointers that have 0xFF in their top byte. MTE_GRANULE_SIZE and related definitions are moved to mte-def.h header that doesn't have any dependencies and is safe to include into any low-level header. Signed-off-by: Vincenzo Frascino Co-developed-by: Andrey Konovalov Signed-off-by: Andrey Konovalov Reviewed-by: Catalin Marinas --- Change-Id: I1b5230254f90dc21a913447cb17f07fea7944ece --- arch/arm64/include/asm/esr.h | 1 + arch/arm64/include/asm/mte-def.h | 15 ++++++++ arch/arm64/include/asm/mte-kasan.h | 56 ++++++++++++++++++++++++++++++ arch/arm64/include/asm/mte.h | 20 +++++++---- arch/arm64/kernel/mte.c | 48 +++++++++++++++++++++++++ arch/arm64/lib/mte.S | 16 +++++++++ 6 files changed, 150 insertions(+), 6 deletions(-) create mode 100644 arch/arm64/include/asm/mte-def.h create mode 100644 arch/arm64/include/asm/mte-kasan.h diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h index 22c81f1edda2..971c20ddfed4 100644 --- a/arch/arm64/include/asm/esr.h +++ b/arch/arm64/include/asm/esr.h @@ -105,6 +105,7 @@ #define ESR_ELx_FSC (0x3F) #define ESR_ELx_FSC_TYPE (0x3C) #define ESR_ELx_FSC_EXTABT (0x10) +#define ESR_ELx_FSC_MTE (0x11) #define ESR_ELx_FSC_SERROR (0x11) #define ESR_ELx_FSC_ACCESS (0x08) #define ESR_ELx_FSC_FAULT (0x04) diff --git a/arch/arm64/include/asm/mte-def.h b/arch/arm64/include/asm/mte-def.h new file mode 100644 index 000000000000..8401ac5840c7 --- /dev/null +++ b/arch/arm64/include/asm/mte-def.h @@ -0,0 +1,15 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020 ARM Ltd. + */ +#ifndef __ASM_MTE_DEF_H +#define __ASM_MTE_DEF_H + +#define MTE_GRANULE_SIZE UL(16) +#define MTE_GRANULE_MASK (~(MTE_GRANULE_SIZE - 1)) +#define MTE_TAG_SHIFT 56 +#define MTE_TAG_SIZE 4 +#define MTE_TAG_MASK GENMASK((MTE_TAG_SHIFT + (MTE_TAG_SIZE - 1)), MTE_TAG_SHIFT) +#define MTE_TAG_MAX (MTE_TAG_MASK >> MTE_TAG_SHIFT) + +#endif /* __ASM_MTE_DEF_H */ diff --git a/arch/arm64/include/asm/mte-kasan.h b/arch/arm64/include/asm/mte-kasan.h new file mode 100644 index 000000000000..3a70fb1807fd --- /dev/null +++ b/arch/arm64/include/asm/mte-kasan.h @@ -0,0 +1,56 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020 ARM Ltd. + */ +#ifndef __ASM_MTE_KASAN_H +#define __ASM_MTE_KASAN_H + +#include + +#ifndef __ASSEMBLY__ + +#include + +/* + * The functions below are meant to be used only for the + * KASAN_HW_TAGS interface defined in asm/memory.h. + */ +#ifdef CONFIG_ARM64_MTE + +static inline u8 mte_get_ptr_tag(void *ptr) +{ + /* Note: The format of KASAN tags is 0xF */ + u8 tag = 0xF0 | (u8)(((u64)(ptr)) >> MTE_TAG_SHIFT); + + return tag; +} + +u8 mte_get_mem_tag(void *addr); +u8 mte_get_random_tag(void); +void *mte_set_mem_tag_range(void *addr, size_t size, u8 tag); + +#else /* CONFIG_ARM64_MTE */ + +static inline u8 mte_get_ptr_tag(void *ptr) +{ + return 0xFF; +} + +static inline u8 mte_get_mem_tag(void *addr) +{ + return 0xFF; +} +static inline u8 mte_get_random_tag(void) +{ + return 0xFF; +} +static inline void *mte_set_mem_tag_range(void *addr, size_t size, u8 tag) +{ + return addr; +} + +#endif /* CONFIG_ARM64_MTE */ + +#endif /* __ASSEMBLY__ */ + +#endif /* __ASM_MTE_KASAN_H */ diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h index 1c99fcadb58c..cf1cd181dcb2 100644 --- a/arch/arm64/include/asm/mte.h +++ b/arch/arm64/include/asm/mte.h @@ -5,14 +5,16 @@ #ifndef __ASM_MTE_H #define __ASM_MTE_H -#define MTE_GRANULE_SIZE UL(16) -#define MTE_GRANULE_MASK (~(MTE_GRANULE_SIZE - 1)) -#define MTE_TAG_SHIFT 56 -#define MTE_TAG_SIZE 4 +#include +#include + +#define __MTE_PREAMBLE ARM64_ASM_PREAMBLE ".arch_extension memtag\n" #ifndef __ASSEMBLY__ +#include #include +#include #include @@ -45,7 +47,9 @@ long get_mte_ctrl(struct task_struct *task); int mte_ptrace_copy_tags(struct task_struct *child, long request, unsigned long addr, unsigned long data); -#else +void mte_assign_mem_tag_range(void *addr, size_t size); + +#else /* CONFIG_ARM64_MTE */ /* unused if !CONFIG_ARM64_MTE, silence the compiler */ #define PG_mte_tagged 0 @@ -80,7 +84,11 @@ static inline int mte_ptrace_copy_tags(struct task_struct *child, return -EIO; } -#endif +static inline void mte_assign_mem_tag_range(void *addr, size_t size) +{ +} + +#endif /* CONFIG_ARM64_MTE */ #endif /* __ASSEMBLY__ */ #endif /* __ASM_MTE_H */ diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c index 52a0638ed967..8f99c65837fd 100644 --- a/arch/arm64/kernel/mte.c +++ b/arch/arm64/kernel/mte.c @@ -13,10 +13,13 @@ #include #include #include +#include #include +#include #include #include +#include #include #include @@ -72,6 +75,51 @@ int memcmp_pages(struct page *page1, struct page *page2) return ret; } +u8 mte_get_mem_tag(void *addr) +{ + if (!system_supports_mte()) + return 0xFF; + + asm(__MTE_PREAMBLE "ldg %0, [%0]" + : "+r" (addr)); + + return mte_get_ptr_tag(addr); +} + +u8 mte_get_random_tag(void) +{ + void *addr; + + if (!system_supports_mte()) + return 0xFF; + + asm(__MTE_PREAMBLE "irg %0, %0" + : "+r" (addr)); + + return mte_get_ptr_tag(addr); +} + +void *mte_set_mem_tag_range(void *addr, size_t size, u8 tag) +{ + void *ptr = addr; + + if ((!system_supports_mte()) || (size == 0)) + return addr; + + /* Make sure that size is MTE granule aligned. */ + WARN_ON(size & (MTE_GRANULE_SIZE - 1)); + + /* Make sure that the address is MTE granule aligned. */ + WARN_ON((u64)addr & (MTE_GRANULE_SIZE - 1)); + + tag = 0xF0 | tag; + ptr = (void *)__tag_set(ptr, tag); + + mte_assign_mem_tag_range(ptr, size); + + return ptr; +} + static void update_sctlr_el1_tcf0(u64 tcf0) { /* ISB required for the kernel uaccess routines */ diff --git a/arch/arm64/lib/mte.S b/arch/arm64/lib/mte.S index cceed41bba15..e63890292bc1 100644 --- a/arch/arm64/lib/mte.S +++ b/arch/arm64/lib/mte.S @@ -149,3 +149,19 @@ SYM_FUNC_START(mte_restore_page_tags) ret SYM_FUNC_END(mte_restore_page_tags) + +/* + * Assign allocation tags for a region of memory based on the pointer tag + * x0 - source pointer + * x1 - size + * + * Note: The address must be non-NULL and MTE_GRANULE_SIZE aligned and + * size must be non-zero and MTE_GRANULE_SIZE aligned. + */ +SYM_FUNC_START(mte_assign_mem_tag_range) +1: stg x0, [x0] + add x0, x0, #MTE_GRANULE_SIZE + subs x1, x1, #MTE_GRANULE_SIZE + b.gt 1b + ret +SYM_FUNC_END(mte_assign_mem_tag_range)