Linux-ARM-Kernel Archive on lore.kernel.org
 help / color / Atom feed
From: Andrey Konovalov <andreyknvl@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-arm-kernel@lists.infradead.org,
	Marco Elver <elver@google.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Kevin Brodsky <kevin.brodsky@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Branislav Rankov <Branislav.Rankov@arm.com>,
	kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, Alexander Potapenko <glider@google.com>,
	Evgenii Stepanov <eugenis@google.com>,
	Andrey Konovalov <andreyknvl@google.com>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	Dmitry Vyukov <dvyukov@google.com>
Subject: [PATCH mm v11 28/42] arm64: kasan: Allow enabling in-kernel MTE
Date: Mon, 23 Nov 2020 21:07:52 +0100
Message-ID: <7352b0a0899af65c2785416c8ca6bf3845b66fa1.1606161801.git.andreyknvl@google.com> (raw)
In-Reply-To: <cover.1606161801.git.andreyknvl@google.com>

From: Vincenzo Frascino <vincenzo.frascino@arm.com>

Hardware tag-based KASAN relies on Memory Tagging Extension (MTE)
feature and requires it to be enabled. MTE supports

This patch adds a new mte_enable_kernel() helper, that enables MTE in
Synchronous mode in EL1 and is intended to be called from KASAN runtime
during initialization.

The Tag Checking operation causes a synchronous data abort as
a consequence of a tag check fault when MTE is configured in
synchronous mode.

As part of this change enable match-all tag for EL1 to allow the
kernel to access user pages without faulting. This is required because
the kernel does not have knowledge of the tags set by the user in a
page.

Note: For MTE, the TCF bit field in SCTLR_EL1 affects only EL1 in a
similar way as TCF0 affects EL0.

MTE that is built on top of the Top Byte Ignore (TBI) feature hence we
enable it as part of this patch as well.

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>
---
Change-Id: I4d67497268bb7f0c2fc5dcacefa1e273df4af71d
---
 arch/arm64/include/asm/mte-kasan.h |  6 ++++++
 arch/arm64/kernel/mte.c            |  7 +++++++
 arch/arm64/mm/proc.S               | 23 ++++++++++++++++++++---
 3 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/mte-kasan.h b/arch/arm64/include/asm/mte-kasan.h
index 3a70fb1807fd..71ff6c6786ac 100644
--- a/arch/arm64/include/asm/mte-kasan.h
+++ b/arch/arm64/include/asm/mte-kasan.h
@@ -29,6 +29,8 @@ 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);
 
+void mte_enable_kernel(void);
+
 #else /* CONFIG_ARM64_MTE */
 
 static inline u8 mte_get_ptr_tag(void *ptr)
@@ -49,6 +51,10 @@ static inline void *mte_set_mem_tag_range(void *addr, size_t size, u8 tag)
 	return addr;
 }
 
+static inline void mte_enable_kernel(void)
+{
+}
+
 #endif /* CONFIG_ARM64_MTE */
 
 #endif /* __ASSEMBLY__ */
diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c
index 86d554ce98b6..7899e165f30a 100644
--- a/arch/arm64/kernel/mte.c
+++ b/arch/arm64/kernel/mte.c
@@ -129,6 +129,13 @@ void *mte_set_mem_tag_range(void *addr, size_t size, u8 tag)
 	return ptr;
 }
 
+void mte_enable_kernel(void)
+{
+	/* Enable MTE Sync Mode for EL1. */
+	sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_SYNC);
+	isb();
+}
+
 static void update_sctlr_el1_tcf0(u64 tcf0)
 {
 	/* ISB required for the kernel uaccess routines */
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 0eaf16b0442a..0d85e6df42bc 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -40,9 +40,15 @@
 #define TCR_CACHE_FLAGS	TCR_IRGN_WBWA | TCR_ORGN_WBWA
 
 #ifdef CONFIG_KASAN_SW_TAGS
-#define TCR_KASAN_FLAGS TCR_TBI1
+#define TCR_KASAN_SW_FLAGS TCR_TBI1
 #else
-#define TCR_KASAN_FLAGS 0
+#define TCR_KASAN_SW_FLAGS 0
+#endif
+
+#ifdef CONFIG_KASAN_HW_TAGS
+#define TCR_KASAN_HW_FLAGS SYS_TCR_EL1_TCMA1 | TCR_TBI1
+#else
+#define TCR_KASAN_HW_FLAGS 0
 #endif
 
 /*
@@ -427,6 +433,10 @@ SYM_FUNC_START(__cpu_setup)
 	 */
 	mov_q	x5, MAIR_EL1_SET
 #ifdef CONFIG_ARM64_MTE
+	mte_tcr	.req	x20
+
+	mov	mte_tcr, #0
+
 	/*
 	 * Update MAIR_EL1, GCR_EL1 and TFSR*_EL1 if MTE is supported
 	 * (ID_AA64PFR1_EL1[11:8] > 1).
@@ -447,6 +457,9 @@ SYM_FUNC_START(__cpu_setup)
 	/* clear any pending tag check faults in TFSR*_EL1 */
 	msr_s	SYS_TFSR_EL1, xzr
 	msr_s	SYS_TFSRE0_EL1, xzr
+
+	/* set the TCR_EL1 bits */
+	mov_q	mte_tcr, TCR_KASAN_HW_FLAGS
 1:
 #endif
 	msr	mair_el1, x5
@@ -456,7 +469,11 @@ SYM_FUNC_START(__cpu_setup)
 	 */
 	mov_q	x10, TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \
 			TCR_TG_FLAGS | TCR_KASLR_FLAGS | TCR_ASID16 | \
-			TCR_TBI0 | TCR_A1 | TCR_KASAN_FLAGS
+			TCR_TBI0 | TCR_A1 | TCR_KASAN_SW_FLAGS
+#ifdef CONFIG_ARM64_MTE
+	orr	x10, x10, mte_tcr
+	.unreq	mte_tcr
+#endif
 	tcr_clear_errata_bits x10, x9, x5
 
 #ifdef CONFIG_ARM64_VA_BITS_52
-- 
2.29.2.454.gaff20da3a2-goog


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply index

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-23 20:07 [PATCH mm v11 00/42] kasan: add hardware tag-based mode for arm64 Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 01/42] kasan: drop unnecessary GPL text from comment headers Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 02/42] kasan: KASAN_VMALLOC depends on KASAN_GENERIC Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 03/42] kasan: group vmalloc code Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 04/42] kasan: shadow declarations only for software modes Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 05/42] kasan: rename (un)poison_shadow to (un)poison_range Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 06/42] kasan: rename KASAN_SHADOW_* to KASAN_GRANULE_* Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 07/42] kasan: only build init.c for software modes Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 08/42] kasan: split out shadow.c from common.c Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 09/42] kasan: define KASAN_MEMORY_PER_SHADOW_PAGE Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 10/42] kasan: rename report and tags files Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 11/42] kasan: don't duplicate config dependencies Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 12/42] kasan: hide invalid free check implementation Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 13/42] kasan: decode stack frame only with KASAN_STACK_ENABLE Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 14/42] kasan, arm64: only init shadow for software modes Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 15/42] kasan, arm64: only use kasan_depth " Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 16/42] kasan, arm64: move initialization message Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 17/42] kasan, arm64: rename kasan_init_tags and mark as __init Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 18/42] kasan: rename addr_has_shadow to addr_has_metadata Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 19/42] kasan: rename print_shadow_for_address to print_memory_metadata Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 20/42] kasan: rename SHADOW layout macros to META Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 21/42] kasan: separate metadata_fetch_row for each mode Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 22/42] kasan, arm64: don't allow SW_TAGS with ARM64_MTE Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 23/42] kasan: introduce CONFIG_KASAN_HW_TAGS Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 24/42] arm64: Enable armv8.5-a asm-arch option Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 25/42] arm64: mte: Add in-kernel MTE helpers Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 26/42] arm64: mte: Reset the page tag in page->flags Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 27/42] arm64: mte: Add in-kernel tag fault handler Andrey Konovalov
2020-12-03 10:26   ` Catalin Marinas
2020-12-03 10:39     ` Vincenzo Frascino
2020-11-23 20:07 ` Andrey Konovalov [this message]
2020-11-23 20:07 ` [PATCH mm v11 29/42] arm64: mte: Convert gcr_user into an exclude mask Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 30/42] arm64: mte: Switch GCR_EL1 in kernel entry and exit Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 31/42] kasan, mm: untag page address in free_reserved_area Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 32/42] arm64: kasan: Align allocations for HW_TAGS Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 33/42] arm64: kasan: Add arch layer for memory tagging helpers Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 34/42] kasan: define KASAN_GRANULE_SIZE for HW_TAGS Andrey Konovalov
2020-11-23 20:07 ` [PATCH mm v11 35/42] kasan, x86, s390: update undef CONFIG_KASAN Andrey Konovalov
2020-11-23 20:08 ` [PATCH mm v11 36/42] kasan, arm64: expand CONFIG_KASAN checks Andrey Konovalov
2020-11-23 20:08 ` [PATCH mm v11 37/42] kasan, arm64: implement HW_TAGS runtime Andrey Konovalov
2020-11-23 20:08 ` [PATCH mm v11 38/42] kasan, arm64: print report from tag fault handler Andrey Konovalov
2020-11-23 20:08 ` [PATCH mm v11 39/42] kasan, mm: reset tags when accessing metadata Andrey Konovalov
2020-11-23 20:08 ` [PATCH mm v11 40/42] kasan, arm64: enable CONFIG_KASAN_HW_TAGS Andrey Konovalov
2020-11-23 20:08 ` [PATCH mm v11 41/42] kasan: add documentation for hardware tag-based mode Andrey Konovalov
2020-11-23 20:08 ` [PATCH mm v11 42/42] kselftest/arm64: Check GCR_EL1 after context switch Andrey Konovalov

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=7352b0a0899af65c2785416c8ca6bf3845b66fa1.1606161801.git.andreyknvl@google.com \
    --to=andreyknvl@google.com \
    --cc=Branislav.Rankov@arm.com \
    --cc=akpm@linux-foundation.org \
    --cc=aryabinin@virtuozzo.com \
    --cc=catalin.marinas@arm.com \
    --cc=dvyukov@google.com \
    --cc=elver@google.com \
    --cc=eugenis@google.com \
    --cc=glider@google.com \
    --cc=kasan-dev@googlegroups.com \
    --cc=kevin.brodsky@arm.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=vincenzo.frascino@arm.com \
    --cc=will.deacon@arm.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-ARM-Kernel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-arm-kernel/0 linux-arm-kernel/git/0.git
	git clone --mirror https://lore.kernel.org/linux-arm-kernel/1 linux-arm-kernel/git/1.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-arm-kernel linux-arm-kernel/ https://lore.kernel.org/linux-arm-kernel \
		linux-arm-kernel@lists.infradead.org
	public-inbox-index linux-arm-kernel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.infradead.lists.linux-arm-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git