From: Ingo Molnar <mingo@kernel.org>
Date: Tue, 24 Mar 2015 20:14:07 +0000 (+0100)
Subject: Merge branch 'x86/urgent' into x86/asm, to resolve conflict
X-Git-Tag: firefly_0821_release~176^2~2028^2~52
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=06ab9c1ba6a19977432b6906b0eee84804212dc6;p=firefly-linux-kernel-4.4.55.git

Merge branch 'x86/urgent' into x86/asm, to resolve conflict

Conflicts:
	arch/x86/kernel/entry_64.S

Signed-off-by: Ingo Molnar <mingo@kernel.org>
---

06ab9c1ba6a19977432b6906b0eee84804212dc6
diff --cc arch/x86/kernel/entry_64.S
index daf5d94c0e78,2babb393915e..bf9afadbb99e
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@@ -261,18 -358,27 +261,28 @@@ system_call_fastpath
  	ja ret_from_sys_call  /* and return regs->ax */
  	movq %r10,%rcx
  	call *sys_call_table(,%rax,8)  # XXX:	 rip relative
 -	movq %rax,RAX-ARGOFFSET(%rsp)
 +	movq %rax,RAX(%rsp)
  /*
   * Syscall return path ending with SYSRET (fast path)
 - * Has incomplete stack frame and undefined top of stack.
 + * Has incompletely filled pt_regs, iret frame is also incomplete.
   */
  ret_from_sys_call:
- 	testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
- 	jnz int_ret_from_sys_call	/* Go the slow path */
 +
  	LOCKDEP_SYS_EXIT
  	DISABLE_INTERRUPTS(CLBR_NONE)
  	TRACE_IRQS_OFF
+ 
+ 	/*
+ 	 * We must check ti flags with interrupts (or at least preemption)
+ 	 * off because we must *never* return to userspace without
+ 	 * processing exit work that is enqueued if we're preempted here.
+ 	 * In particular, returning to userspace with any of the one-shot
+ 	 * flags (TIF_NOTIFY_RESUME, TIF_USER_RETURN_NOTIFY, etc) set is
+ 	 * very bad.
+ 	 */
 -	testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 -	jnz int_ret_from_sys_call_fixup	/* Go the the slow path */
++	testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
++	jnz int_ret_from_sys_call_irqs_off	/* Go to the slow path */
+ 
  	CFI_REMEMBER_STATE
  	/*
  	 * sysretq will re-enable interrupts: