Commit a57dae3a authored by Roland McGrath's avatar Roland McGrath Committed by Ingo Molnar

x86: fix iret exception recovery on 64-bit

This change broke recovery of exceptions in iret:

   commit 72fe4858
   Author: Glauber de Oliveira Costa <gcosta@redhat.com>

       x86: replace privileged instructions with paravirt macros

The ENTRY(native_iret) macro adds alignment padding before the iretq
instruction, so "iret_label" no longer points exactly at the instruction.
It was sloppy to leave the old "iret_label" label behind when replacing
its nearby use.  Removing it would have revealed the other use of the
label later in the file, and upon noticing that use, anyone exercising
the minimum of attention to detail expected of anyone touching this
subtle code would realize it needed to change as well.
Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent b5556a67
......@@ -582,7 +582,6 @@ retint_restore_args: /* return to kernel space */
TRACE_IRQS_IRETQ
restore_args:
RESTORE_ARGS 0,8,0
iret_label:
#ifdef CONFIG_PARAVIRT
INTERRUPT_RETURN
#endif
......@@ -920,7 +919,7 @@ error_kernelspace:
iret run with kernel gs again, so don't set the user space flag.
B stepping K8s sometimes report an truncated RIP for IRET
exceptions returning to compat mode. Check for these here too. */
leaq iret_label(%rip),%rbp
leaq native_iret(%rip),%rbp
cmpq %rbp,RIP(%rsp)
je error_swapgs
movl %ebp,%ebp /* zero extend */
......
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