@@ -67,7 +67,6 @@
# define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
#else
# define preempt_stop(clobbers)
-# define resume_kernel restore_all_kernel
#endif
.macro TRACE_IRQS_IRET
@@ -755,7 +754,7 @@ END(ret_from_fork)
andl $SEGMENT_RPL_MASK, %eax
#endif
cmpl $USER_RPL, %eax
- jb resume_kernel # not returning to v8086 or userspace
+ jb restore_all_kernel # not returning to v8086 or userspace
ENTRY(resume_userspace)
DISABLE_INTERRUPTS(CLBR_ANY)
@@ -765,18 +764,6 @@ ENTRY(resume_userspace)
jmp restore_all
END(ret_from_exception)
-#ifdef CONFIG_PREEMPT
-ENTRY(resume_kernel)
- DISABLE_INTERRUPTS(CLBR_ANY)
- cmpl $0, PER_CPU_VAR(__preempt_count)
- jnz restore_all_kernel
- testl $X86_EFLAGS_IF, PT_EFLAGS(%esp) # interrupts off (exception path) ?
- jz restore_all_kernel
- call preempt_schedule_irq
- jmp restore_all_kernel
-END(resume_kernel)
-#endif
-
GLOBAL(__begin_SYSENTER_singlestep_region)
/*
* All code from here through __end_SYSENTER_singlestep_region is subject
@@ -1027,6 +1014,15 @@ ENTRY(entry_INT80_32)
INTERRUPT_RETURN
restore_all_kernel:
+#ifdef CONFIG_PREEMPT
+ DISABLE_INTERRUPTS(CLBR_ANY)
+ cmpl $0, PER_CPU_VAR(__preempt_count)
+ jnz .Lno_preempt
+ testl $X86_EFLAGS_IF, PT_EFLAGS(%esp) # interrupts off (exception path) ?
+ jz .Lno_preempt
+ call preempt_schedule_irq
+.Lno_preempt:
+#endif
TRACE_IRQS_IRET
PARANOID_EXIT_TO_KERNEL_MODE
BUG_IF_WRONG_CR3
The code flow around the return from interrupt preemption point seems needlesly complicated. There is only one site jumping to resume_kernel, and none (outside of resume_kernel) jumping to restore_all_kernel. Inline resume_kernel in restore_all_kernel and avoid the CONFIG_PREEMPT dependent label. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- arch/x86/entry/entry_32.S | 24 ++++++++++-------------- 1 file changed, 10 insertions(+), 14 deletions(-)