[patch V4 part 5 16/31] x86/entry: Use idtentry for interrupts

Thomas Gleixner
2020-05-05T14:17:28Z

Replace the extra interrupt handling code and reuse the existing idtentry
machinery. This moves the irq stack switching on 64 bit from ASM to C code;
32bit already does the stack switching in C.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/entry/entry_32.S | 31 -------------------------------
arch/x86/entry/entry_64.S | 31 +++----------------------------
arch/x86/include/asm/hw_irq.h | 1 -
arch/x86/include/asm/idtentry.h | 10 ++++++++--
arch/x86/include/asm/irq.h | 2 --
arch/x86/include/asm/traps.h | 1 -
arch/x86/kernel/apic/apic.c | 23 ++++++++---------------
arch/x86/kernel/apic/msi.c | 3 ++-
arch/x86/kernel/irq.c | 27 +++++++--------------------
9 files changed, 28 insertions(+), 101 deletions(-)

--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -1229,37 +1229,6 @@ SYM_FUNC_END(entry_INT80_32)
#endif
.endm

-#ifdef CONFIG_X86_LOCAL_APIC
-SYM_CODE_START_LOCAL(common_spurious)
- ASM_CLAC
- SAVE_ALL switch_stacks=1
- ENCODE_FRAME_POINTER
- TRACE_IRQS_OFF
- 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 smp_spurious_interrupt
- jmp ret_from_intr
-SYM_CODE_END(common_spurious)
-#endif
-
-/*
- * the CPU automatically disables interrupts when executing an IRQ vector,
- * so IRQ-flags tracing has to follow that:
- */
- .p2align CONFIG_X86_L1_CACHE_SHIFT
-SYM_CODE_START_LOCAL(common_interrupt)
- ASM_CLAC
- SAVE_ALL switch_stacks=1
- ENCODE_FRAME_POINTER
- TRACE_IRQS_OFF
- 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 do_IRQ
- jmp ret_from_intr
-SYM_CODE_END(common_interrupt)
-
#define BUILD_INTERRUPT3(name, nr, fn) \
SYM_FUNC_START(name) \
ASM_CLAC; \
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -738,32 +738,7 @@ SYM_CODE_START(interrupt_entry)
SYM_CODE_END(interrupt_entry)
_ASM_NOKPROBE(interrupt_entry)

-
-/* Interrupt entry/exit. */
-
-/*
- * The interrupt stubs push vector onto the stack and
- * then jump to common_spurious/interrupt.
- */
-SYM_CODE_START_LOCAL(common_spurious)
- call interrupt_entry
- UNWIND_HINT_REGS indirect=1
- movq ORIG_RAX(%rdi), %rsi /* get vector from stack */
- movq $-1, ORIG_RAX(%rdi) /* no syscall to restart */
- call smp_spurious_interrupt /* rdi points to pt_regs */
- jmp ret_from_intr
-SYM_CODE_END(common_spurious)
-_ASM_NOKPROBE(common_spurious)
-
-/* common_interrupt is a hotpath. Align it */
- .p2align CONFIG_X86_L1_CACHE_SHIFT
-SYM_CODE_START_LOCAL(common_interrupt)
- call interrupt_entry
- UNWIND_HINT_REGS indirect=1
- movq ORIG_RAX(%rdi), %rsi /* get vector from stack */
- movq $-1, ORIG_RAX(%rdi) /* no syscall to restart */
- call do_IRQ /* rdi points to pt_regs */
- /* 0(%rsp): old RSP */
+SYM_CODE_START_LOCAL(common_interrupt_return)
ret_from_intr:
DISABLE_INTERRUPTS(CLBR_ANY)
TRACE_IRQS_OFF
@@ -945,8 +920,8 @@ SYM_INNER_LABEL(native_irq_return_iret,
*/
jmp native_irq_return_iret
#endif
-SYM_CODE_END(common_interrupt)
-_ASM_NOKPROBE(common_interrupt)
+SYM_CODE_END(common_interrupt_return)
+_ASM_NOKPROBE(common_interrupt_return)

/*
* APIC interrupts.
--- a/arch/x86/include/asm/hw_irq.h
+++ b/arch/x86/include/asm/hw_irq.h
@@ -38,7 +38,6 @@ extern asmlinkage void error_interrupt(v
extern asmlinkage void irq_work_interrupt(void);
extern asmlinkage void uv_bau_message_intr1(void);

-extern asmlinkage void spurious_interrupt(void);
extern asmlinkage void spurious_apic_interrupt(void);
extern asmlinkage void thermal_interrupt(void);
extern asmlinkage void reschedule_interrupt(void);
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -403,7 +403,7 @@ SYM_CODE_START(irq_entries_start)
.rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
UNWIND_HINT_IRET_REGS
.byte 0x6a, vector
- jmp common_interrupt
+ jmp asm_common_interrupt
.align 8
vector=vector+1
.endr
@@ -416,7 +416,7 @@ SYM_CODE_START(spurious_entries_start)
.rept (NR_VECTORS - FIRST_SYSTEM_VECTOR)
UNWIND_HINT_IRET_REGS
.byte 0x6a, vector
- jmp common_spurious
+ jmp asm_spurious_interrupt
.align 8
vector=vector+1
.endr
@@ -487,6 +487,12 @@ DECLARE_IDTENTRY_DF(X86_TRAP_DF, exc_dou
DECLARE_IDTENTRY(X86_TRAP_OTHER, exc_xen_hypervisor_callback);
#endif

+/* Device interrupts common/spurious */
+DECLARE_IDTENTRY_IRQ(X86_TRAP_OTHER, common_interrupt);
+#ifdef CONFIG_X86_LOCAL_APIC
+DECLARE_IDTENTRY_IRQ(X86_TRAP_OTHER, spurious_interrupt);
+#endif
+
#undef X86_TRAP_OTHER

#endif
--- a/arch/x86/include/asm/irq.h
+++ b/arch/x86/include/asm/irq.h
@@ -36,8 +36,6 @@ extern void native_init_IRQ(void);

extern void handle_irq(struct irq_desc *desc, struct pt_regs *regs);

-extern __visible void do_IRQ(struct pt_regs *regs, unsigned long vector);
-
extern void init_ISA_irqs(void);

extern void __init init_IRQ(void);
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -43,7 +43,6 @@ asmlinkage void smp_deferred_error_inter
void smp_apic_timer_interrupt(struct pt_regs *regs);
void smp_error_interrupt(struct pt_regs *regs);
void smp_spurious_apic_interrupt(struct pt_regs *regs);
-void smp_spurious_interrupt(struct pt_regs *regs, unsigned long vector);
asmlinkage void smp_irq_move_cleanup_interrupt(void);

#ifdef CONFIG_VMAP_STACK
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -2153,9 +2153,9 @@ void __init register_lapic_address(unsig
*/

/**
- * smp_spurious_interrupt - Catch all for interrupts raised on unused vectors
+ * spurious_interrupt - Catch all for interrupts raised on unused vectors
* @regs: Pointer to pt_regs on stack
- * @error_code: The vector number is in the lower 8 bits
+ * @vector: The vector number
*
* This is invoked from ASM entry code to catch all interrupts which
* trigger on an entry which is routed to the common_spurious idtentry
@@ -2163,18 +2163,10 @@ void __init register_lapic_address(unsig
*
* Also called from smp_spurious_apic_interrupt().
*/
-__visible void __irq_entry smp_spurious_interrupt(struct pt_regs *regs,
- unsigned long vector)
+DEFINE_IDTENTRY_IRQ(spurious_interrupt)
{
u32 v;

- entering_irq();
- /*
- * The push in the entry ASM code which stores the vector number on
- * the stack in the error code slot is sign expanding. Just use the
- * lower 8 bits.
- */
- vector &= 0xFF;
trace_spurious_apic_entry(vector);

inc_irq_stat(irq_spurious_count);
@@ -2195,21 +2187,22 @@ void __init register_lapic_address(unsig
*/
v = apic_read(APIC_ISR + ((vector & ~0x1f) >> 1));
if (v & (1 << (vector & 0x1f))) {
- pr_info("Spurious interrupt (vector 0x%02lx) on CPU#%d. Acked\n",
+ pr_info("Spurious interrupt (vector 0x%02x) on CPU#%d. Acked\n",
vector, smp_processor_id());
ack_APIC_irq();
} else {
- pr_info("Spurious interrupt (vector 0x%02lx) on CPU#%d. Not pending!\n",
+ pr_info("Spurious interrupt (vector 0x%02x) on CPU#%d. Not pending!\n",
vector, smp_processor_id());
}
out:
trace_spurious_apic_exit(vector);
- exiting_irq();
}

__visible void smp_spurious_apic_interrupt(struct pt_regs *regs)
{
- smp_spurious_interrupt(regs, SPURIOUS_APIC_VECTOR);
+ entering_irq();
+ __spurious_interrupt(regs, SPURIOUS_APIC_VECTOR);
+ exiting_irq();
}

/*
--- a/arch/x86/kernel/apic/msi.c
+++ b/arch/x86/kernel/apic/msi.c
@@ -115,7 +115,8 @@ msi_set_affinity(struct irq_data *irqd,
* denote it as spurious which is no harm as this is a rare event
* and interrupt handlers have to cope with spurious interrupts
* anyway. If the vector is unused, then it is marked so it won't
- * trigger the 'No irq handler for vector' warning in do_IRQ().
+ * trigger the 'No irq handler for vector' warning in
+ * common_interrupt().
*
* This requires to hold vector lock to prevent concurrent updates to
* the affected vector.
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -19,6 +19,7 @@
#include <asm/mce.h>
#include <asm/hw_irq.h>
#include <asm/desc.h>
+#include <asm/traps.h>

#define CREATE_TRACE_POINTS
#include <asm/trace/irq_vectors.h>
@@ -226,37 +227,25 @@ u64 arch_irq_stat(void)

/*
- * do_IRQ handles all normal device IRQ's (the special
- * SMP cross-CPU interrupts have their own specific
- * handlers).
+ * common_interrupt() handles all normal device IRQ's (the special SMP
+ * cross-CPU interrupts have their own entry points).
*/
-__visible void __irq_entry do_IRQ(struct pt_regs *regs, unsigned long vector)
+DEFINE_IDTENTRY_IRQ(common_interrupt)
{
struct pt_regs *old_regs = set_irq_regs(regs);
struct irq_desc *desc;

- entering_irq();
- /*
- * The push in the entry ASM code which stores the vector number on
- * the stack in the error code slot is sign expanding. Just use the
- * lower 8 bits.
- */
- vector &= 0xFF;
-
- /* entering_irq() tells RCU that we're not quiescent. Check it. */
+ /* entry code tells RCU that we're not quiescent. Check it. */
RCU_LOCKDEP_WARN(!rcu_is_watching(), "IRQ failed to wake up RCU");

desc = __this_cpu_read(vector_irq[vector]);
if (likely(!IS_ERR_OR_NULL(desc))) {
- if (IS_ENABLED(CONFIG_X86_32))
- handle_irq(desc, regs);
- else
- generic_handle_irq_desc(desc);
+ handle_irq(desc, regs);
} else {
ack_APIC_irq();

if (desc == VECTOR_UNUSED) {
- pr_emerg_ratelimited("%s: %d.%lu No irq handler for vector\n",
+ pr_emerg_ratelimited("%s: %d.%u No irq handler for vector\n",
__func__, smp_processor_id(),
vector);
} else {
@@ -264,8 +253,6 @@ u64 arch_irq_stat(void)
}
}

- exiting_irq();
-
set_irq_regs(old_regs);
}