[patch V5 21/38] x86/entry: Add IRQENTRY_IRQ macro

Thomas Gleixner
2020-05-12T22:25:20Z

Provide a seperate IDTENTRY macro for device interrupts. Similar to
IDTENTRY_ERRORCODE with the addition of invoking irq_enter/exit_rcu() and
providing the errorcode as a 'u8' argument to the C function, which
truncates the sign extended vector number.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/entry/entry_32.S | 14 +++++++++++
arch/x86/entry/entry_64.S | 14 +++++++++++
arch/x86/include/asm/idtentry.h | 47 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 75 insertions(+)

--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -751,6 +751,20 @@ SYM_CODE_START(\asmsym)
SYM_CODE_END(\asmsym)
.endm

+.macro idtentry_irq vector cfunc
+ .p2align CONFIG_X86_L1_CACHE_SHIFT
+SYM_CODE_START_LOCAL(asm_\cfunc)
+ ASM_CLAC
+ SAVE_ALL switch_stacks=1
+ ENCODE_FRAME_POINTER
+ movl %esp, %eax
+ movl PT_ORIG_EAX(%esp), %edx /* get the vector from stack */
+ movl $-1, PT_ORIG_EAX(%esp) /* no syscall to restart */
+ call \cfunc
+ jmp handle_exception_return
+SYM_CODE_END(asm_\cfunc)
+.endm
+
/*
* Include the defines which emit the idt entries which are shared
* shared between 32 and 64 bit.
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -528,6 +528,20 @@ SYM_CODE_END(\asmsym)
.endm

/*
+ * Interrupt entry/exit.
+ *
+ + The interrupt stubs push (vector) onto the stack, which is the error_code
+ * position of idtentry exceptions, and jump to one of the two idtentry points
+ * (common/spurious).
+ *
+ * common_interrupt is a hotpath, align it to a cache line
+ */
+.macro idtentry_irq vector cfunc
+ .p2align CONFIG_X86_L1_CACHE_SHIFT
+ idtentry \vector asm_\cfunc \cfunc has_error_code=1
+.endm
+
+/*
* MCE and DB exceptions
*/
#define CPU_TSS_IST(x) PER_CPU_VAR(cpu_tss_rw) + (TSS_ist + (x) * 8)
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -163,6 +163,49 @@ static __always_inline void __##func(str
#define DEFINE_IDTENTRY_RAW_ERRORCODE(func) \
__visible noinstr void func(struct pt_regs *regs, unsigned long error_code)

+/**
+ * DECLARE_IDTENTRY_IRQ - Declare functions for device interrupt IDT entry
+ * points (common/spurious)
+ * @vector: Vector number (ignored for C)
+ * @func: Function name of the entry point
+ *
+ * Maps to DECLARE_IDTENTRY_ERRORCODE()
+ */
+#define DECLARE_IDTENTRY_IRQ(vector, func) \
+ DECLARE_IDTENTRY_ERRORCODE(vector, func)
+
+/**
+ * DEFINE_IDTENTRY_IRQ - Emit code for device interrupt IDT entry points
+ * @func: Function name of the entry point
+ *
+ * The vector number is pushed by the low level entry stub and handed
+ * to the function as error_code argument which needs to be truncated
+ * to an u8 because the push is sign extending.
+ *
+ * On 64bit dtentry_enter/exit() are invoked in the ASM entry code before
+ * and after switching to the interrupt stack. On 32bit this happens in C.
+ *
+ * irq_enter/exit_rcu() are invoked before the function body and the
+ * KVM L1D flush request is set.
+ */
+#define DEFINE_IDTENTRY_IRQ(func) \
+static __always_inline void __##func(struct pt_regs *regs, u8 vector); \
+ \
+__visible noinstr void func(struct pt_regs *regs, \
+ unsigned long error_code) \
+{ \
+ idtentry_enter(regs); \
+ instrumentation_begin(); \
+ irq_enter_rcu(); \
+ kvm_set_cpu_l1tf_flush_l1d(); \
+ __##func (regs, (u8)error_code); \
+ irq_exit_rcu(); \
+ lockdep_hardirq_exit(); \
+ instrumentation_end(); \
+ idtentry_exit(regs); \
+} \
+ \
+static __always_inline void __##func(struct pt_regs *regs, u8 vector)

#ifdef CONFIG_X86_64
/**
@@ -295,6 +338,10 @@ static __always_inline void __##func(str
#define DECLARE_IDTENTRY_RAW_ERRORCODE(vector, func) \
DECLARE_IDTENTRY_ERRORCODE(vector, func)

+/* Entries for common/spurious (device) interrupts */
+#define DECLARE_IDTENTRY_IRQ(vector, func) \
+ idtentry_irq vector func
+
#ifdef CONFIG_X86_64
# define DECLARE_IDTENTRY_MCE(vector, func) \
idtentry_mce_db vector asm_##func func