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| author |   James Morse <james.morse@arm.com> | 2016-04-27 17:47:02 +0100 |
|---|---|---|
| committer |   Will Deacon <will.deacon@arm.com> | 2016-04-28 12:05:46 +0100 |
| commit | 00a44cdaba0900c63a003e0c431f506f49376a90 (patch) | |
| tree | 98dbb48f951a2ecab7a0ee09e89bf09a4d754a36 /arch/arm64/kvm | |
| parent | arm64: Cleanup SCTLR flags (diff) | |
| download | linux-dev-00a44cdaba0900c63a003e0c431f506f49376a90.tar.xz linux-dev-00a44cdaba0900c63a003e0c431f506f49376a90.zip | |
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>
Diffstat (limited to 'arch/arm64/kvm')
| -rw-r--r-- | arch/arm64/kvm/hyp.S | 7 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/hyp-entry.S | 6 |
2 files changed, 8 insertions, 5 deletions
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S index 48f19a37b3df..4ee5612f43ea 100644 --- a/arch/arm64/kvm/hyp.S +++ b/arch/arm64/kvm/hyp.S @@ -38,13 +38,18 @@ * 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 3488894397ff..43b4b28159d9 100644 --- a/arch/arm64/kvm/hyp/hyp-entry.S +++ b/arch/arm64/kvm/hyp/hyp-entry.S @@ -42,19 +42,17 @@ * 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. |