path: root/arch/x86/entry/entry_64.S
diff options
authorThomas Gleixner <tglx@linutronix.de>2019-06-28 13:11:54 +0200
committerThomas Gleixner <tglx@linutronix.de>2019-07-03 10:12:31 +0200
commitf8a8fe61fec8006575699559ead88b0b833d5cad (patch)
tree55311ccce060c4d13795e077f4675f3614696360 /arch/x86/entry/entry_64.S
parentb7107a67f0d125459fe41f86e8079afd1a5e0b15 (diff)
x86/irq: Seperate unused system vectors from spurious entry again
Quite some time ago the interrupt entry stubs for unused vectors in the system vector range got removed and directly mapped to the spurious interrupt vector entry point. Sounds reasonable, but it's subtly broken. The spurious interrupt vector entry point pushes vector number 0xFF on the stack which makes the whole logic in __smp_spurious_interrupt() pointless. As a consequence any spurious interrupt which comes from a vector != 0xFF is treated as a real spurious interrupt (vector 0xFF) and not acknowledged. That subsequently stalls all interrupt vectors of equal and lower priority, which brings the system to a grinding halt. This can happen because even on 64-bit the system vector space is not guaranteed to be fully populated. A full compile time handling of the unused vectors is not possible because quite some of them are conditonally populated at runtime. Bring the entry stubs back, which wastes 160 bytes if all stubs are unused, but gains the proper handling back. There is no point to selectively spare some of the stubs which are known at compile time as the required code in the IDT management would be way larger and convoluted. Do not route the spurious entries through common_interrupt and do_IRQ() as the original code did. Route it to smp_spurious_interrupt() which evaluates the vector number and acts accordingly now that the real vector numbers are handed in. Fixup the pr_warn so the actual spurious vector (0xff) is clearly distiguished from the other vectors and also note for the vectored case whether it was pending in the ISR or not. "Spurious APIC interrupt (vector 0xFF) on CPU#0, should never happen." "Spurious interrupt vector 0xed on CPU#1. Acked." "Spurious interrupt vector 0xee on CPU#1. Not pending!." Fixes: 2414e021ac8d ("x86: Avoid building unused IRQ entry stubs") Reported-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Jan Beulich <jbeulich@suse.com> Link: https://lkml.kernel.org/r/20190628111440.550568228@linutronix.de
Diffstat (limited to 'arch/x86/entry/entry_64.S')
1 files changed, 26 insertions, 4 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 20e45d9b4e15..6d835991bb23 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -375,6 +375,18 @@ ENTRY(irq_entries_start)
+ .align 8
+ pushq $(~vector+0x80) /* Note: always in signed byte range */
+ jmp common_spurious
+ .align 8
+ vector=vector+1
+ .endr
pushq %rax
@@ -571,10 +583,20 @@ _ASM_NOKPROBE(interrupt_entry)
/* Interrupt entry/exit. */
- /*
- * The interrupt stubs push (~vector+0x80) onto the stack and
- * then jump to common_interrupt.
- */
+ * The interrupt stubs push (~vector+0x80) onto the stack and
+ * then jump to common_spurious/interrupt.
+ */
+ addq $-0x80, (%rsp) /* Adjust vector to [-256, -1] range */
+ call interrupt_entry
+ UNWIND_HINT_REGS indirect=1
+ call smp_spurious_interrupt /* rdi points to pt_regs */
+ jmp ret_from_intr
+/* common_interrupt is a hotpath. Align it */
addq $-0x80, (%rsp) /* Adjust vector to [-256, -1] range */