This is a note to let you know that I've just added the patch titled

    ARM: virt: simplify __hyp_stub_install epilog

to the 3.7-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     arm-virt-simplify-__hyp_stub_install-epilog.patch
and it can be found in the queue-3.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From d01723479e6a6c70c83295f7847477a016d5e14a Mon Sep 17 00:00:00 2001
From: Marc Zyngier <[email protected]>
Date: Fri, 4 Jan 2013 17:44:15 +0000
Subject: ARM: virt: simplify __hyp_stub_install epilog

From: Marc Zyngier <[email protected]>

commit d01723479e6a6c70c83295f7847477a016d5e14a upstream.

__hyp_stub_install duplicates quite a bit of safe_svcmode_maskall
by forcing the CPU back to SVC. This is unnecessary, as
safe_svcmode_maskall is called just after.

Furthermore, the way we build SPSR_hyp is buggy as we fail to mask
the interrupts, leading to interesting behaviours on TC2 + UEFI.

The fix is to simply remove this code and rely on safe_svcmode_maskall
to do the right thing.

Reviewed-by: Dave Martin <[email protected]>
Reported-by: Harry Liebel <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 arch/arm/kernel/hyp-stub.S |   12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -120,7 +120,8 @@ ENTRY(__hyp_stub_install_secondary)
  * Eventually, CPU-specific code might be needed -- assume not for now
  *
  * This code relies on the "eret" instruction to synchronize the
- * various coprocessor accesses.
+ * various coprocessor accesses. This is done when we switch to SVC
+ * (see safe_svcmode_maskall).
  */
        @ Now install the hypervisor stub:
        adr     r7, __hyp_stub_vectors
@@ -155,14 +156,7 @@ THUMB(     orr     r7, #(1 << 30)  )       @ HSCTLR.TE
 1:
 #endif
 
-       bic     r7, r4, #MODE_MASK
-       orr     r7, r7, #SVC_MODE
-THUMB( orr     r7, r7, #PSR_T_BIT      )
-       msr     spsr_cxsf, r7           @ This is SPSR_hyp.
-
-       __MSR_ELR_HYP(14)               @ msr elr_hyp, lr
-       __ERET                          @ return, switching to SVC mode
-                                       @ The boot CPU mode is left in r4.
+       bx      lr                      @ The boot CPU mode is left in r4.
 ENDPROC(__hyp_stub_install_secondary)
 
 __hyp_stub_do_trap:


Patches currently in stable-queue which might be from [email protected] are

queue-3.7/arm-virt-simplify-__hyp_stub_install-epilog.patch
queue-3.7/arm-virt-boot-secondary-cpus-through-the-right-entry-point.patch
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