1 files changed, 45 insertions, 3 deletions

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index b86f332c96a6..9b2aeaac9a6b 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -627,6 +627,46 @@ END(stub_rt_sigreturn)
    vector already pushed) */
 #define XCPT_FRAME _frame ORIG_RAX
 
+/*
+ * Build the entry stubs and pointer table with some assembler magic.
+ * We pack 7 stubs into a single 32-byte chunk, which will fit in a
+ * single cache line on all modern x86 implementations.
+ */
+        .section .init.rodata,"a"
+ENTRY(interrupt)
+        .text
+        .p2align 5
+        .p2align CONFIG_X86_L1_CACHE_SHIFT
+ENTRY(irq_entries_start)
+        INTR_FRAME
+vector=FIRST_EXTERNAL_VECTOR
+.rept (NR_VECTORS-FIRST_EXTERNAL_VECTOR+6)/7
+        .balign 32
+  .rept 7
+    .if vector < NR_VECTORS
+      .if vector != FIRST_EXTERNAL_VECTOR
+        CFI_ADJUST_CFA_OFFSET -8
+      .endif
+1:      pushq $(~vector+0x80)   /* Note: always in signed byte range */
+        CFI_ADJUST_CFA_OFFSET 8
+      .if ((vector-FIRST_EXTERNAL_VECTOR)%7) != 6
+        jmp 2f
+      .endif
+      .previous
+        .quad 1b
+      .text
+vector=vector+1
+    .endif
+  .endr
+2:      jmp common_interrupt
+.endr
+        CFI_ENDPROC
+END(irq_entries_start)
+
+.previous
+END(interrupt)
+.previous
+
 /* 
  * Interrupt entry/exit.
  *
@@ -635,11 +675,12 @@ END(stub_rt_sigreturn)
  * Entry runs with interrupts off.      
  */ 
 
-/* 0(%rsp): interrupt number */ 
+/* 0(%rsp): ~(interrupt number)+0x80 */ 
         .macro interrupt func
+        addq $-0x80,(%rsp)              /* Adjust vector to [-256,-1] range */
         cld
         SAVE_ARGS
-        leaq -ARGOFFSET(%rsp),%rdi      # arg1 for handler
+        leaq -ARGOFFSET(%rsp),%rdi      /* arg1 for handler */
         pushq %rbp
         /*
          * Save rbp twice: One is for marking the stack frame, as usual, and the
@@ -670,7 +711,8 @@ END(stub_rt_sigreturn)
         call \func
         .endm
 
-ENTRY(common_interrupt)
+        .p2align CONFIG_X86_L1_CACHE_SHIFT
+common_interrupt:
         XCPT_FRAME
         interrupt do_IRQ
         /* 0(%rsp): oldrsp-ARGOFFSET */