3 files changed, 33 insertions, 48 deletions

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index f955d25076ba..239ff5fcec6a 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -758,9 +758,9 @@ static struct subsys_interface mc_cpu_interface = {
 };
 
 /**
- * mc_bp_resume - Update boot CPU microcode during resume.
+ * microcode_bsp_resume - Update boot CPU microcode during resume.
  */
-static void mc_bp_resume(void)
+void microcode_bsp_resume(void)
 {
 	int cpu = smp_processor_id();
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
@@ -772,7 +772,7 @@ static void mc_bp_resume(void)
 }
 
 static struct syscore_ops mc_syscore_ops = {
-	.resume			= mc_bp_resume,
+	.resume			= microcode_bsp_resume,
 };
 
 static int mc_cpu_starting(unsigned int cpu)
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index c049561f373a..e28ab0ecc537 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -41,17 +41,7 @@ struct fpu_state_config fpu_user_cfg __ro_after_init;
  */
 struct fpstate init_fpstate __ro_after_init;
 
-/*
- * Track whether the kernel is using the FPU state
- * currently.
- *
- * This flag is used:
- *
- *   - by IRQ context code to potentially use the FPU
- *     if it's unused.
- *
- *   - to debug kernel_fpu_begin()/end() correctness
- */
+/* Track in-kernel FPU usage */
 static DEFINE_PER_CPU(bool, in_kernel_fpu);
 
 /*
@@ -59,42 +49,37 @@ static DEFINE_PER_CPU(bool, in_kernel_fpu);
  */
 DEFINE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx);
 
-static bool kernel_fpu_disabled(void)
-{
-	return this_cpu_read(in_kernel_fpu);
-}
-
-static bool interrupted_kernel_fpu_idle(void)
-{
-	return !kernel_fpu_disabled();
-}
-
-/*
- * Were we in user mode (or vm86 mode) when we were
- * interrupted?
- *
- * Doing kernel_fpu_begin/end() is ok if we are running
- * in an interrupt context from user mode - we'll just
- * save the FPU state as required.
- */
-static bool interrupted_user_mode(void)
-{
-	struct pt_regs *regs = get_irq_regs();
-	return regs && user_mode(regs);
-}
-
 /*
  * Can we use the FPU in kernel mode with the
  * whole "kernel_fpu_begin/end()" sequence?
- *
- * It's always ok in process context (ie "not interrupt")
- * but it is sometimes ok even from an irq.
  */
 bool irq_fpu_usable(void)
 {
-	return !in_interrupt() ||
-		interrupted_user_mode() ||
-		interrupted_kernel_fpu_idle();
+	if (WARN_ON_ONCE(in_nmi()))
+		return false;
+
+	/* In kernel FPU usage already active? */
+	if (this_cpu_read(in_kernel_fpu))
+		return false;
+
+	/*
+	 * When not in NMI or hard interrupt context, FPU can be used in:
+	 *
+	 * - Task context except from within fpregs_lock()'ed critical
+	 *   regions.
+	 *
+	 * - Soft interrupt processing context which cannot happen
+	 *   while in a fpregs_lock()'ed critical region.
+	 */
+	if (!in_hardirq())
+		return true;
+
+	/*
+	 * In hard interrupt context it's safe when soft interrupts
+	 * are enabled, which means the interrupt did not hit in
+	 * a fpregs_lock()'ed critical region.
+	 */
+	return !softirq_count();
 }
 EXPORT_SYMBOL(irq_fpu_usable);
 
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index 794fdef2501a..38185aedf7d1 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -339,11 +339,11 @@ static bool stack_access_ok(struct unwind_state *state, unsigned long _addr,
 	struct stack_info *info = &state->stack_info;
 	void *addr = (void *)_addr;
 
-	if (!on_stack(info, addr, len) &&
-	    (get_stack_info(addr, state->task, info, &state->stack_mask)))
-		return false;
+	if (on_stack(info, addr, len))
+		return true;
 
-	return true;
+	return !get_stack_info(addr, state->task, info, &state->stack_mask) &&
+		on_stack(info, addr, len);
 }
 
 static bool deref_stack_reg(struct unwind_state *state, unsigned long addr,