Thread (9 messages) flat view 9 messages, 3 authors, 2021-07-28
STALE1859d LANDED: 3 (3M)

1 review trailer (1 from subsystem maintainers); landed in mainline as 638982a03fbc on 2021-07-28.

[PATCH v11 1/5] arm64: mte: rename gcr_user_excl to mte_ctrl

From: Peter Collingbourne <hidden>
Date: 2021-07-27 20:55:26
Subsystem: arm64 port (aarch64 architecture), the rest · Maintainers: Catalin Marinas, Will Deacon, Linus Torvalds

We are going to use this field to store more data. To prepare for
that, rename it and change the users to rely on the bit position of
gcr_user_excl in mte_ctrl.

Link: https://linux-review.googlesource.com/id/Ie1fd18e480100655f5d22137f5b22f4f3a9f9e2e
Signed-off-by: Peter Collingbourne <redacted>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
---
 arch/arm64/include/asm/processor.h |  5 ++++-
 arch/arm64/kernel/asm-offsets.c    |  2 +-
 arch/arm64/kernel/entry.S          |  4 ++--
 arch/arm64/kernel/mte.c            | 14 ++++++++------
 4 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index b6517fd03d7b..54d34276fa91 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -16,6 +16,9 @@
  */
 #define NET_IP_ALIGN	0
 
+#define MTE_CTRL_GCR_USER_EXCL_SHIFT	0
+#define MTE_CTRL_GCR_USER_EXCL_MASK	0xffff
+
 #ifndef __ASSEMBLY__
 
 #include <linux/build_bug.h>
@@ -153,7 +156,7 @@ struct thread_struct {
 #endif
 #endif
 #ifdef CONFIG_ARM64_MTE
-	u64			gcr_user_excl;
+	u64			mte_ctrl;
 #endif
 	u64			sctlr_user;
 };
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index c85670692afa..551427ae8cc5 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -52,7 +52,7 @@ int main(void)
   DEFINE(THREAD_KEYS_KERNEL,	offsetof(struct task_struct, thread.keys_kernel));
 #endif
 #ifdef CONFIG_ARM64_MTE
-  DEFINE(THREAD_GCR_EL1_USER,	offsetof(struct task_struct, thread.gcr_user_excl));
+  DEFINE(THREAD_MTE_CTRL,	offsetof(struct task_struct, thread.mte_ctrl));
 #endif
   BLANK();
   DEFINE(S_X0,			offsetof(struct pt_regs, regs[0]));
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 863d44f73028..40c3543de3bc 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -167,7 +167,7 @@ alternative_else_nop_endif
 	 * the RRND (bit[16]) setting.
 	 */
 	mrs_s	\tmp2, SYS_GCR_EL1
-	bfi	\tmp2, \tmp, #0, #16
+	bfxil	\tmp2, \tmp, #MTE_CTRL_GCR_USER_EXCL_SHIFT, #16
 	msr_s	SYS_GCR_EL1, \tmp2
 #endif
 	.endm
@@ -190,7 +190,7 @@ alternative_else_nop_endif
 alternative_if_not ARM64_MTE
 	b	1f
 alternative_else_nop_endif
-	ldr	\tmp, [\tsk, #THREAD_GCR_EL1_USER]
+	ldr	\tmp, [\tsk, #THREAD_MTE_CTRL]
 
 	mte_set_gcr \tmp, \tmp2
 1:
diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c
index 36f51b0e438a..a5269558210c 100644
--- a/arch/arm64/kernel/mte.c
+++ b/arch/arm64/kernel/mte.c
@@ -195,7 +195,7 @@ void mte_check_tfsr_el1(void)
 
 static void set_gcr_el1_excl(u64 excl)
 {
-	current->thread.gcr_user_excl = excl;
+	current->thread.mte_ctrl = excl;
 
 	/*
 	 * SYS_GCR_EL1 will be set to current->thread.gcr_user_excl value
@@ -260,8 +260,8 @@ void mte_suspend_exit(void)
 long set_mte_ctrl(struct task_struct *task, unsigned long arg)
 {
 	u64 sctlr = task->thread.sctlr_user & ~SCTLR_EL1_TCF0_MASK;
-	u64 gcr_excl = ~((arg & PR_MTE_TAG_MASK) >> PR_MTE_TAG_SHIFT) &
-		       SYS_GCR_EL1_EXCL_MASK;
+	u64 mte_ctrl = (~((arg & PR_MTE_TAG_MASK) >> PR_MTE_TAG_SHIFT) &
+			SYS_GCR_EL1_EXCL_MASK) << MTE_CTRL_GCR_USER_EXCL_SHIFT;
 
 	if (!system_supports_mte())
 		return 0;
@@ -282,10 +282,10 @@ long set_mte_ctrl(struct task_struct *task, unsigned long arg)
 
 	if (task != current) {
 		task->thread.sctlr_user = sctlr;
-		task->thread.gcr_user_excl = gcr_excl;
+		task->thread.mte_ctrl = mte_ctrl;
 	} else {
 		set_task_sctlr_el1(sctlr);
-		set_gcr_el1_excl(gcr_excl);
+		set_gcr_el1_excl(mte_ctrl);
 	}
 
 	return 0;
@@ -294,7 +294,9 @@ long set_mte_ctrl(struct task_struct *task, unsigned long arg)
 long get_mte_ctrl(struct task_struct *task)
 {
 	unsigned long ret;
-	u64 incl = ~task->thread.gcr_user_excl & SYS_GCR_EL1_EXCL_MASK;
+	u64 mte_ctrl = task->thread.mte_ctrl;
+	u64 incl = (~mte_ctrl >> MTE_CTRL_GCR_USER_EXCL_SHIFT) &
+		   SYS_GCR_EL1_EXCL_MASK;
 
 	if (!system_supports_mte())
 		return 0;
-- 
2.32.0.432.gabb21c7263-goog


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