Messages in this thread Patch in this message | | | From | Ian Campbell <> | Subject | [PATCH 2/3] x86: make 64 bit ret_from_fork a little more similar to 32 bit | Date | Tue, 5 Jul 2011 14:00:13 +0100 |
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The 64 bit version resets EFLAGS before calling schedule_tail() and therefore leaves EFLAGS.IF clear. 32 bit resets EFLAGS after calling schedule_tail() and therefore leaves EFLAGS.IF set. I don't think there is any practical difference between the two approaches since interrupts are actually reenabled within schedule_tail (schedule_tail->finish_task_switch->finish_lock_switch->raw_spin_unlock_irq->...->local_irq_enable) so arbitrarily pick the 32 bit version and make 64 bit look like that.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Cc: x86@kernel.org --- arch/x86/kernel/entry_64.S | 7 ++++--- 1 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index b50d142..9c28bd5 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -394,13 +394,14 @@ END(save_paranoid) ENTRY(ret_from_fork) DEFAULT_FRAME - LOCK ; btr $TIF_FORK,TI_flags(%r8) - pushq_cfi $0x0002 - popfq_cfi # reset kernel eflags + LOCK ; btr $TIF_FORK,TI_flags(%r8) call schedule_tail # rdi: 'prev' task parameter + pushq_cfi $0x0202 + popfq_cfi # reset kernel eflags + GET_THREAD_INFO(%rcx) RESTORE_REST -- 1.7.2.5
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