1 files changed, 35 insertions, 26 deletions

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 143b3e72c25e..e7226c4c7493 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -114,7 +114,12 @@
  *   returned from the 2nd syscall yet, TIF_FOREIGN_FPSTATE is still set so
  *   whatever is in the FPSIMD registers is not saved to memory, but discarded.
  */
-static DEFINE_PER_CPU(struct fpsimd_state *, fpsimd_last_state);
+struct fpsimd_last_state_struct {
+	struct fpsimd_state *st;
+	bool sve_in_use;
+};
+
+static DEFINE_PER_CPU(struct fpsimd_last_state_struct, fpsimd_last_state);
 
 /* Default VL for tasks that don't set it explicitly: */
 static int sve_default_vl = -1;
@@ -862,7 +867,7 @@ asmlinkage void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs)
 asmlinkage void do_fpsimd_exc(unsigned int esr, struct pt_regs *regs)
 {
 	siginfo_t info;
-	unsigned int si_code = 0;
+	unsigned int si_code = FPE_FIXME;
 
 	if (esr & FPEXC_IOF)
 		si_code = FPE_FLTINV;
@@ -905,7 +910,7 @@ void fpsimd_thread_switch(struct task_struct *next)
 		 */
 		struct fpsimd_state *st = &next->thread.fpsimd_state;
 
-		if (__this_cpu_read(fpsimd_last_state) == st
+		if (__this_cpu_read(fpsimd_last_state.st) == st
 		    && st->cpu == smp_processor_id())
 			clear_tsk_thread_flag(next, TIF_FOREIGN_FPSTATE);
 		else
@@ -992,6 +997,21 @@ void fpsimd_signal_preserve_current_state(void)
 }
 
 /*
+ * Associate current's FPSIMD context with this cpu
+ * Preemption must be disabled when calling this function.
+ */
+static void fpsimd_bind_to_cpu(void)
+{
+	struct fpsimd_last_state_struct *last =
+		this_cpu_ptr(&fpsimd_last_state);
+	struct fpsimd_state *st = &current->thread.fpsimd_state;
+
+	last->st = st;
+	last->sve_in_use = test_thread_flag(TIF_SVE);
+	st->cpu = smp_processor_id();
+}
+
+/*
  * Load the userland FPSIMD state of 'current' from memory, but only if the
  * FPSIMD state already held in the registers is /not/ the most recent FPSIMD
  * state of 'current'
@@ -1004,11 +1024,8 @@ void fpsimd_restore_current_state(void)
 	local_bh_disable();
 
 	if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE)) {
-		struct fpsimd_state *st = &current->thread.fpsimd_state;
-
 		task_fpsimd_load();
-		__this_cpu_write(fpsimd_last_state, st);
-		st->cpu = smp_processor_id();
+		fpsimd_bind_to_cpu();
 	}
 
 	local_bh_enable();
@@ -1019,25 +1036,21 @@ void fpsimd_restore_current_state(void)
  * flag that indicates that the FPSIMD register contents are the most recent
  * FPSIMD state of 'current'
  */
-void fpsimd_update_current_state(struct fpsimd_state *state)
+void fpsimd_update_current_state(struct user_fpsimd_state const *state)
 {
 	if (!system_supports_fpsimd())
 		return;
 
 	local_bh_disable();
 
-	if (system_supports_sve() && test_thread_flag(TIF_SVE)) {
-		current->thread.fpsimd_state = *state;
+	current->thread.fpsimd_state.user_fpsimd = *state;
+	if (system_supports_sve() && test_thread_flag(TIF_SVE))
 		fpsimd_to_sve(current);
-	}
-	task_fpsimd_load();
 
-	if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE)) {
-		struct fpsimd_state *st = &current->thread.fpsimd_state;
+	task_fpsimd_load();
 
-		__this_cpu_write(fpsimd_last_state, st);
-		st->cpu = smp_processor_id();
-	}
+	if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE))
+		fpsimd_bind_to_cpu();
 
 	local_bh_enable();
 }
@@ -1052,7 +1065,7 @@ void fpsimd_flush_task_state(struct task_struct *t)
 
 static inline void fpsimd_flush_cpu_state(void)
 {
-	__this_cpu_write(fpsimd_last_state, NULL);
+	__this_cpu_write(fpsimd_last_state.st, NULL);
 }
 
 /*
@@ -1065,14 +1078,10 @@ static inline void fpsimd_flush_cpu_state(void)
 #ifdef CONFIG_ARM64_SVE
 void sve_flush_cpu_state(void)
 {
-	struct fpsimd_state *const fpstate = __this_cpu_read(fpsimd_last_state);
-	struct task_struct *tsk;
-
-	if (!fpstate)
-		return;
+	struct fpsimd_last_state_struct const *last =
+		this_cpu_ptr(&fpsimd_last_state);
 
-	tsk = container_of(fpstate, struct task_struct, thread.fpsimd_state);
-	if (test_tsk_thread_flag(tsk, TIF_SVE))
+	if (last->st && last->sve_in_use)
 		fpsimd_flush_cpu_state();
 }
 #endif /* CONFIG_ARM64_SVE */
@@ -1267,7 +1276,7 @@ static inline void fpsimd_pm_init(void) { }
 #ifdef CONFIG_HOTPLUG_CPU
 static int fpsimd_cpu_dead(unsigned int cpu)
 {
-	per_cpu(fpsimd_last_state, cpu) = NULL;
+	per_cpu(fpsimd_last_state.st, cpu) = NULL;
 	return 0;
 }