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authorAlex Shi <alex.shi@linaro.org>2016-05-24 16:58:26 +0800
committerAlex Shi <alex.shi@linaro.org>2016-05-24 17:15:06 +0800
commit8411a7b227dac86913d60ee360a5283402b5c50f (patch)
tree03440b16c77a765372621006d1c031577f99d279
parent3200bf6148648ea42c77c908416ba8fdd097b39f (diff)
downloadlinux-linaro-stable-8411a7b227dac86913d60ee360a5283402b5c50f.tar.gz
arm64: kvm: Move lr save/restore from do_el2_call into EL1
Today the 'hvc' calling KVM or the hyp-stub is expected to preserve all registers. KVM saves/restores the registers it needs on the EL2 stack using do_el2_call(). The hyp-stub has no stack, later patches need to be able to be able to clobber the link register. Move the link register save/restore to the the call sites. Signed-off-by: James Morse <james.morse@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> (cherry picked from commit 00a44cdaba0900c63a003e0c431f506f49376a90) Signed-off-by: Alex Shi <alex.shi@linaro.org> Conflicts: arch/arm64/kvm/hyp.S
-rw-r--r--arch/arm64/kernel/hyp-stub.S10
-rw-r--r--arch/arm64/kvm/hyp.S7
-rw-r--r--arch/arm64/kvm/hyp/hyp-entry.S6
3 files changed, 16 insertions, 7 deletions
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index a272f33..7eab8ac 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -101,10 +101,16 @@ ENDPROC(\label)
*/
ENTRY(__hyp_get_vectors)
+ str lr, [sp, #-16]!
mov x0, xzr
- // fall through
-ENTRY(__hyp_set_vectors)
hvc #0
+ ldr lr, [sp], #16
ret
ENDPROC(__hyp_get_vectors)
+
+ENTRY(__hyp_set_vectors)
+ str lr, [sp, #-16]!
+ hvc #0
+ ldr lr, [sp], #16
+ ret
ENDPROC(__hyp_set_vectors)
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index bfd019b..b8fe4d1 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -38,14 +38,19 @@
* A function pointer with a value of 0 has a special meaning, and is
* used to implement __hyp_get_vectors in the same way as in
* arch/arm64/kernel/hyp_stub.S.
+ * HVC behaves as a 'bl' call and will clobber lr.
*/
ENTRY(kvm_call_hyp)
-alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
+alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
+ str lr, [sp, #-16]!
hvc #0
+ ldr lr, [sp], #16
ret
alternative_else
b __vhe_hyp_call
nop
+ nop
+ nop
alternative_endif
ENDPROC(kvm_call_hyp)
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 8950cdb..f4e6e0f 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -43,19 +43,17 @@
* Shuffle the parameters before calling the function
* pointed to in x0. Assumes parameters in x[1,2,3].
*/
- sub sp, sp, #16
- str lr, [sp]
mov lr, x0
mov x0, x1
mov x1, x2
mov x2, x3
blr lr
- ldr lr, [sp]
- add sp, sp, #16
.endm
ENTRY(__vhe_hyp_call)
+ str lr, [sp, #-16]!
do_el2_call
+ ldr lr, [sp], #16
/*
* We used to rely on having an exception return to get
* an implicit isb. In the E2H case, we don't have it anymore.