arm64: mte: rename gcr_user_excl to mte_ctrl

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/Ie1fd18e480100655f5d22137f5b22f4f3a9f9e2eSigned-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210727205300.2554659-2-pcc@google.comAcked-by: Will Deacon <will@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

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;
 };

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]));

arch/arm64/kernel/entry.S

@@ -175,7 +175,7 @@ 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
@@ -198,7 +198,7 @@ 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:

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;