Thread (49 messages) 49 messages, 3 authors, 2020-10-09

Re: [PATCH v4 27/39] arm64: kasan: Enable in-kernel MTE

From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2020-10-02 14:00:25
Also in: linux-mm, lkml

On Fri, Oct 02, 2020 at 01:10:28AM +0200, Andrey Konovalov wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 23c326a06b2d..6c1a6621d769 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
+#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
Don't we miss the TBI1 bit here? I think the v3 version of this patch
was better.

-- 
Catalin

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