From: Joerg Roedel <jroe...@suse.de>

Use a separate return path when we know we are returning to
the kernel. This allows us to put the PTI cr3-switch and the
switch to the entry-stack into the return-to-user path
without further checking.

Signed-off-by: Joerg Roedel <jroe...@suse.de>
---
 arch/x86/entry/entry_32.S | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 3a319fd..2f04d6e 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -65,7 +65,7 @@
 # define preempt_stop(clobbers)        DISABLE_INTERRUPTS(clobbers); 
TRACE_IRQS_OFF
 #else
 # define preempt_stop(clobbers)
-# define resume_kernel         restore_all
+# define resume_kernel         restore_all_kernel
 #endif
 
 .macro TRACE_IRQS_IRET
@@ -399,9 +399,9 @@ ENTRY(resume_kernel)
        DISABLE_INTERRUPTS(CLBR_ANY)
 .Lneed_resched:
        cmpl    $0, PER_CPU_VAR(__preempt_count)
-       jnz     restore_all
+       jnz     restore_all_kernel
        testl   $X86_EFLAGS_IF, PT_EFLAGS(%esp) # interrupts off (exception 
path) ?
-       jz      restore_all
+       jz      restore_all_kernel
        call    preempt_schedule_irq
        jmp     .Lneed_resched
 END(resume_kernel)
@@ -606,6 +606,11 @@ restore_all:
         */
        INTERRUPT_RETURN
 
+restore_all_kernel:
+       TRACE_IRQS_IRET
+       RESTORE_REGS 4
+       jmp     .Lirq_return
+
 .section .fixup, "ax"
 ENTRY(iret_exc )
        pushl   $0                              # no error code
-- 
2.7.4

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