x86/entry: Convert device interrupts to inline stack switching

Convert device interrupts to inline stack switching by replacing the
existing macro implementation with the new inline version. Tweak the
function signature of the actual handler function to have the vector
argument as u32. That allows the inline macro to avoid extra intermediates
and lets the compiler be smarter about the whole thing.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210210002512.769728139@linutronix.de

1 files changed, 31 insertions, 27 deletions

diff --git a/arch/x86/include/asm/irq_stack.h b/arch/x86/include/asm/irq_stack.h
index 05c37e7b3bcc..dabc0cf60df5 100644
--- a/arch/x86/include/asm/irq_stack.h
+++ b/arch/x86/include/asm/irq_stack.h
@@ -162,14 +162,35 @@
 			      SYSVEC_CONSTRAINTS, regs);		\
 }
 
+/*
+ * As in ASM_CALL_SYSVEC above the clobbers force the compiler to store
+ * @regs and @vector in callee saved registers.
+ */
+#define ASM_CALL_IRQ							\
+	"call irq_enter_rcu				\n"		\
+	"movq	%[arg1], %%rdi				\n"		\
+	"movl	%[arg2], %%esi				\n"		\
+	"call %P[__func]				\n"		\
+	"call irq_exit_rcu				\n"
+
+#define IRQ_CONSTRAINTS	, [arg1] "r" (regs), [arg2] "r" (vector)
+
+#define run_irq_on_irqstack_cond(func, regs, vector)			\
+{									\
+	assert_function_type(func, void (*)(struct pt_regs *, u32));	\
+	assert_arg_type(regs, struct pt_regs *);			\
+	assert_arg_type(vector, u32);					\
+									\
+	call_on_irqstack_cond(func, regs, ASM_CALL_IRQ,			\
+			      IRQ_CONSTRAINTS, regs, vector);		\
+}
+
 static __always_inline bool irqstack_active(void)
 {
 	return __this_cpu_read(hardirq_stack_inuse);
 }
 
 void asm_call_on_stack(void *sp, void (*func)(void), void *arg);
-void asm_call_irq_on_stack(void *sp, void (*func)(struct irq_desc *desc),
-			   struct irq_desc *desc);
 
 static __always_inline void __run_on_irqstack(void (*func)(void))
 {
@@ -180,17 +201,6 @@ static __always_inline void __run_on_irqstack(void (*func)(void))
 	__this_cpu_write(hardirq_stack_inuse, false);
 }
 
-static __always_inline void
-__run_irq_on_irqstack(void (*func)(struct irq_desc *desc),
-		      struct irq_desc *desc)
-{
-	void *tos = __this_cpu_read(hardirq_stack_ptr);
-
-	__this_cpu_write(hardirq_stack_inuse, true);
-	asm_call_irq_on_stack(tos, func, desc);
-	__this_cpu_write(hardirq_stack_inuse, false);
-}
-
 #else /* CONFIG_X86_64 */
 
 /* System vector handlers always run on the stack they interrupted. */
@@ -201,10 +211,16 @@ __run_irq_on_irqstack(void (*func)(struct irq_desc *desc),
 	irq_exit_rcu();							\
 }
 
+/* Switches to the irq stack within func() */
+#define run_irq_on_irqstack_cond(func, regs, vector)			\
+{									\
+	irq_enter_rcu();						\
+	func(regs, vector);						\
+	irq_exit_rcu();							\
+}
+
 static inline bool irqstack_active(void) { return false; }
 static inline void __run_on_irqstack(void (*func)(void)) { }
-static inline void __run_irq_on_irqstack(void (*func)(struct irq_desc *desc),
-					 struct irq_desc *desc) { }
 #endif /* !CONFIG_X86_64 */
 
 static __always_inline bool irq_needs_irq_stack(struct pt_regs *regs)
@@ -228,16 +244,4 @@ static __always_inline void run_on_irqstack_cond(void (*func)(void),
 		func();
 }
 
-static __always_inline void
-run_irq_on_irqstack_cond(void (*func)(struct irq_desc *desc), struct irq_desc *desc,
-			 struct pt_regs *regs)
-{
-	lockdep_assert_irqs_disabled();
-
-	if (irq_needs_irq_stack(regs))
-		__run_irq_on_irqstack(func, desc);
-	else
-		func(desc);
-}
-
 #endif