diff options
| author | Andrew Scull <ascull@google.com> | 2021-01-25 14:54:15 +0000 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2021-01-25 15:50:35 +0000 |
| commit | e500b805c39daff2670494fff94909d7e3d094d9 (patch) | |
| tree | 5713a620c16136faf4b202c54475b7b705b12f07 /arch | |
| parent | 139bc8a6146d92822c866cf2fd410159c56b3648 (diff) | |
KVM: arm64: Don't clobber x4 in __do_hyp_init
arm_smccc_1_1_hvc() only adds write contraints for x0-3 in the inline
assembly for the HVC instruction so make sure those are the only
registers that change when __do_hyp_init is called.
Tested-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210125145415.122439-3-ascull@google.com
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/kvm/hyp/nvhe/hyp-init.S | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S index 31b060a44045..b17bf19217f1 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S +++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S @@ -47,6 +47,8 @@ __invalid: b . /* + * Only uses x0..x3 so as to not clobber callee-saved SMCCC registers. + * * x0: SMCCC function ID * x1: struct kvm_nvhe_init_params PA */ @@ -70,9 +72,9 @@ __do_hyp_init: eret 1: mov x0, x1 - mov x4, lr - bl ___kvm_hyp_init - mov lr, x4 + mov x3, lr + bl ___kvm_hyp_init // Clobbers x0..x2 + mov lr, x3 /* Hello, World! */ mov x0, #SMCCC_RET_SUCCESS @@ -82,8 +84,8 @@ SYM_CODE_END(__kvm_hyp_init) /* * Initialize the hypervisor in EL2. * - * Only uses x0..x3 so as to not clobber callee-saved SMCCC registers - * and leave x4 for the caller. + * Only uses x0..x2 so as to not clobber callee-saved SMCCC registers + * and leave x3 for the caller. * * x0: struct kvm_nvhe_init_params PA */ @@ -112,9 +114,9 @@ alternative_else_nop_endif /* * Set the PS bits in TCR_EL2. */ - ldr x1, [x0, #NVHE_INIT_TCR_EL2] - tcr_compute_pa_size x1, #TCR_EL2_PS_SHIFT, x2, x3 - msr tcr_el2, x1 + ldr x0, [x0, #NVHE_INIT_TCR_EL2] + tcr_compute_pa_size x0, #TCR_EL2_PS_SHIFT, x1, x2 + msr tcr_el2, x0 isb @@ -193,7 +195,7 @@ SYM_CODE_START_LOCAL(__kvm_hyp_init_cpu) /* Enable MMU, set vectors and stack. */ mov x0, x28 - bl ___kvm_hyp_init // Clobbers x0..x3 + bl ___kvm_hyp_init // Clobbers x0..x2 /* Leave idmap. */ mov x0, x29 |