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From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, andreyknvl@google.com,
	aryabinin@virtuozzo.com, Branislav.Rankov@arm.com,
	catalin.marinas@arm.com, dvyukov@google.com, elver@google.com,
	eugenis@google.com, glider@google.com, gor@linux.ibm.com,
	kevin.brodsky@arm.com, linux-mm@kvack.org,
	mm-commits@vger.kernel.org, torvalds@linux-foundation.org,
	vincenzo.frascino@arm.com, will.deacon@arm.com
Subject: [patch 37/78] arm64: mte: add in-kernel MTE helpers
Date: Fri, 18 Dec 2020 14:03:26 -0800
Message-ID: <20201218220326.MNvex-upo%akpm@linux-foundation.org> (raw)
In-Reply-To: <20201218140046.497484741326828e5b5d46ec@linux-foundation.org>

From: Vincenzo Frascino <vincenzo.frascino@arm.com>
Subject: arm64: mte: add in-kernel MTE helpers

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.

Link: https://lkml.kernel.org/r/c31bf759b4411b2d98cdd801eb928e241584fd1f.1606161801.git.andreyknvl@google.com
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Co-developed-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 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(-)

--- a/arch/arm64/include/asm/esr.h~arm64-mte-add-in-kernel-mte-helpers
+++ a/arch/arm64/include/asm/esr.h
@@ -106,6 +106,7 @@
 #define ESR_ELx_FSC_TYPE	(0x3C)
 #define ESR_ELx_FSC_LEVEL	(0x03)
 #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)
--- /dev/null
+++ a/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  */
--- a/arch/arm64/include/asm/mte.h~arm64-mte-add-in-kernel-mte-helpers
+++ a/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 <asm/compiler.h>
+#include <asm/mte-def.h>
+
+#define __MTE_PREAMBLE		ARM64_ASM_PREAMBLE ".arch_extension memtag\n"
 
 #ifndef __ASSEMBLY__
 
+#include <linux/bitfield.h>
 #include <linux/page-flags.h>
+#include <linux/types.h>
 
 #include <asm/pgtable-types.h>
 
@@ -45,7 +47,9 @@ long get_mte_ctrl(struct task_struct *ta
 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(s
 	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  */
--- /dev/null
+++ a/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 <asm/mte-def.h>
+
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+
+/*
+ * 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<x> */
+	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  */
--- a/arch/arm64/kernel/mte.c~arm64-mte-add-in-kernel-mte-helpers
+++ a/arch/arm64/kernel/mte.c
@@ -13,10 +13,13 @@
 #include <linux/swap.h>
 #include <linux/swapops.h>
 #include <linux/thread_info.h>
+#include <linux/types.h>
 #include <linux/uio.h>
 
+#include <asm/barrier.h>
 #include <asm/cpufeature.h>
 #include <asm/mte.h>
+#include <asm/mte-kasan.h>
 #include <asm/ptrace.h>
 #include <asm/sysreg.h>
 
@@ -72,6 +75,51 @@ int memcmp_pages(struct page *page1, str
 	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 */
--- a/arch/arm64/lib/mte.S~arm64-mte-add-in-kernel-mte-helpers
+++ a/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)
_

  parent reply index

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-18 22:00 incoming Andrew Morton
2020-12-18 22:01 ` [patch 01/78] mm/memcg: bail early from swap accounting if memcg disabled Andrew Morton
2020-12-18 22:01 ` [patch 02/78] mm/memcg: warning on !memcg after readahead page charged Andrew Morton
2020-12-18 22:01 ` [patch 03/78] mm/memcg: remove unused definitions Andrew Morton
2020-12-18 22:01 ` [patch 04/78] mm, kvm: account kvm_vcpu_mmap to kmemcg Andrew Morton
2020-12-18 22:01 ` [patch 05/78] mm/memcontrol:rewrite mem_cgroup_page_lruvec() Andrew Morton
2020-12-18 22:01 ` [patch 06/78] epoll: check for events when removing a timed out thread from the wait queue Andrew Morton
2020-12-18 22:01 ` [patch 07/78] epoll: simplify signal handling Andrew Morton
2020-12-18 22:01 ` [patch 08/78] epoll: pull fatal signal checks into ep_send_events() Andrew Morton
2020-12-18 22:01 ` [patch 09/78] epoll: move eavail next to the list_empty_careful check Andrew Morton
2020-12-18 22:01 ` [patch 10/78] epoll: simplify and optimize busy loop logic Andrew Morton
2020-12-18 22:02 ` [patch 11/78] epoll: pull all code between fetch_events and send_event into the loop Andrew Morton
2020-12-18 22:02 ` [patch 12/78] epoll: replace gotos with a proper loop Andrew Morton
2020-12-18 22:02 ` [patch 13/78] epoll: eliminate unnecessary lock for zero timeout Andrew Morton
2020-12-18 22:02 ` [patch 14/78] kasan: drop unnecessary GPL text from comment headers Andrew Morton
2020-12-18 22:02 ` [patch 15/78] kasan: KASAN_VMALLOC depends on KASAN_GENERIC Andrew Morton
2020-12-18 22:02 ` [patch 16/78] kasan: group vmalloc code Andrew Morton
2020-12-18 22:02 ` [patch 17/78] kasan: shadow declarations only for software modes Andrew Morton
2020-12-18 22:02 ` [patch 18/78] kasan: rename (un)poison_shadow to (un)poison_range Andrew Morton
2020-12-18 22:02 ` [patch 19/78] kasan: rename KASAN_SHADOW_* to KASAN_GRANULE_* Andrew Morton
2020-12-18 22:02 ` [patch 20/78] kasan: only build init.c for software modes Andrew Morton
2020-12-18 22:02 ` [patch 21/78] kasan: split out shadow.c from common.c Andrew Morton
2020-12-19  0:28   ` Marco Elver
2020-12-19  1:13     ` Andrew Morton
2020-12-19 10:01       ` Marco Elver
2020-12-19 10:11       ` Marco Elver
2020-12-19 18:01       ` Andrey Konovalov
2020-12-19 19:17       ` Linus Torvalds
2020-12-19 19:26         ` Linus Torvalds
2020-12-21  9:46         ` Alexander Potapenko
2020-12-21 17:41           ` Linus Torvalds
2020-12-22 18:38             ` Andrew Morton
2020-12-18 22:02 ` [patch 22/78] kasan: define KASAN_MEMORY_PER_SHADOW_PAGE Andrew Morton
2020-12-18 22:02 ` [patch 23/78] kasan: rename report and tags files Andrew Morton
2020-12-18 22:02 ` [patch 24/78] kasan: don't duplicate config dependencies Andrew Morton
2020-12-18 22:02 ` [patch 25/78] kasan: hide invalid free check implementation Andrew Morton
2020-12-18 22:02 ` [patch 26/78] kasan: decode stack frame only with KASAN_STACK_ENABLE Andrew Morton
2020-12-18 22:02 ` [patch 27/78] kasan, arm64: only init shadow for software modes Andrew Morton
2020-12-18 22:02 ` [patch 28/78] kasan, arm64: only use kasan_depth " Andrew Morton
2020-12-18 22:03 ` [patch 29/78] kasan, arm64: move initialization message Andrew Morton
2020-12-18 22:03 ` [patch 30/78] kasan, arm64: rename kasan_init_tags and mark as __init Andrew Morton
2020-12-18 22:03 ` [patch 31/78] kasan: rename addr_has_shadow to addr_has_metadata Andrew Morton
2020-12-18 22:03 ` [patch 32/78] kasan: rename print_shadow_for_address to print_memory_metadata Andrew Morton
2020-12-18 22:03 ` [patch 33/78] kasan: rename SHADOW layout macros to META Andrew Morton
2020-12-18 22:03 ` [patch 34/78] kasan: separate metadata_fetch_row for each mode Andrew Morton
2020-12-18 22:03 ` [patch 35/78] kasan: introduce CONFIG_KASAN_HW_TAGS Andrew Morton
2020-12-18 22:03 ` [patch 36/78] arm64: enable armv8.5-a asm-arch option Andrew Morton
2020-12-18 22:03 ` Andrew Morton [this message]
2020-12-18 22:03 ` [patch 38/78] arm64: mte: reset the page tag in page->flags Andrew Morton
2020-12-18 22:03 ` [patch 39/78] arm64: mte: add in-kernel tag fault handler Andrew Morton
2020-12-18 22:03 ` [patch 40/78] arm64: kasan: allow enabling in-kernel MTE Andrew Morton
2020-12-18 22:03 ` [patch 41/78] arm64: mte: convert gcr_user into an exclude mask Andrew Morton
2020-12-18 22:03 ` [patch 42/78] arm64: mte: switch GCR_EL1 in kernel entry and exit Andrew Morton
2020-12-18 22:03 ` [patch 43/78] kasan, mm: untag page address in free_reserved_area Andrew Morton
2020-12-18 22:03 ` [patch 44/78] arm64: kasan: align allocations for HW_TAGS Andrew Morton
2020-12-18 22:03 ` [patch 45/78] arm64: kasan: add arch layer for memory tagging helpers Andrew Morton
2020-12-18 22:03 ` [patch 46/78] kasan: define KASAN_GRANULE_SIZE for HW_TAGS Andrew Morton
2020-12-18 22:03 ` [patch 47/78] kasan, x86, s390: update undef CONFIG_KASAN Andrew Morton
2020-12-18 22:04 ` [patch 48/78] kasan, arm64: expand CONFIG_KASAN checks Andrew Morton
2020-12-18 22:04 ` [patch 49/78] kasan, arm64: implement HW_TAGS runtime Andrew Morton
2020-12-18 22:04 ` [patch 50/78] kasan, arm64: print report from tag fault handler Andrew Morton
2020-12-18 22:04 ` [patch 51/78] kasan, mm: reset tags when accessing metadata Andrew Morton
2020-12-18 22:04 ` [patch 52/78] kasan, arm64: enable CONFIG_KASAN_HW_TAGS Andrew Morton
2020-12-18 22:04 ` [patch 53/78] kasan: add documentation for hardware tag-based mode Andrew Morton
2020-12-18 22:04 ` [patch 54/78] kselftest/arm64: check GCR_EL1 after context switch Andrew Morton
2020-12-18 22:04 ` [patch 55/78] kasan: simplify quarantine_put call site Andrew Morton
2020-12-18 22:04 ` [patch 56/78] kasan: rename get_alloc/free_info Andrew Morton
2020-12-18 22:04 ` [patch 57/78] kasan: introduce set_alloc_info Andrew Morton
2020-12-18 22:04 ` [patch 58/78] kasan, arm64: unpoison stack only with CONFIG_KASAN_STACK Andrew Morton
2020-12-18 22:04 ` [patch 59/78] kasan: allow VMAP_STACK for HW_TAGS mode Andrew Morton
2020-12-18 22:04 ` [patch 60/78] kasan: remove __kasan_unpoison_stack Andrew Morton
2020-12-18 22:04 ` [patch 61/78] kasan: inline kasan_reset_tag for tag-based modes Andrew Morton
2020-12-18 22:04 ` [patch 62/78] kasan: inline random_tag for HW_TAGS Andrew Morton
2020-12-18 22:04 ` [patch 63/78] kasan: open-code kasan_unpoison_slab Andrew Morton
2020-12-18 22:04 ` [patch 64/78] kasan: inline (un)poison_range and check_invalid_free Andrew Morton
2020-12-18 22:05 ` [patch 65/78] kasan: add and integrate kasan boot parameters Andrew Morton
2020-12-18 22:05 ` [patch 66/78] kasan, mm: check kasan_enabled in annotations Andrew Morton
2020-12-18 22:05 ` [patch 67/78] kasan, mm: rename kasan_poison_kfree Andrew Morton
2020-12-18 22:05 ` [patch 68/78] kasan: don't round_up too much Andrew Morton
2020-12-18 22:05 ` [patch 69/78] kasan: simplify assign_tag and set_tag calls Andrew Morton
2020-12-18 22:05 ` [patch 70/78] kasan: clarify comment in __kasan_kfree_large Andrew Morton
2020-12-18 22:05 ` [patch 71/78] kasan: sanitize objects when metadata doesn't fit Andrew Morton
2020-12-18 22:05 ` [patch 72/78] kasan, mm: allow cache merging with no metadata Andrew Morton
2020-12-18 22:05 ` [patch 73/78] kasan: update documentation Andrew Morton
2020-12-18 22:05 ` [patch 74/78] mm/Kconfig: fix spelling mistake "whats" -> "what's" Andrew Morton
2020-12-18 22:05 ` [patch 75/78] epoll: convert internal api to timespec64 Andrew Morton
2020-12-18 22:05 ` [patch 76/78] epoll: add syscall epoll_pwait2 Andrew Morton
2020-12-18 22:05 ` [patch 77/78] epoll: wire up " Andrew Morton
2020-12-18 22:05 ` [patch 78/78] selftests/filesystems: expand epoll with epoll_pwait2 Andrew Morton

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