From 87b26801f02ca9d7a110eb598dae8cd5d3bcace2 Mon Sep 17 00:00:00 2001 From: Andrew Scull Date: Mon, 25 Jan 2021 14:54:14 +0000 Subject: [PATCH 1/3] KVM: arm64: Simplify __kvm_hyp_init HVC detection The arguments for __do_hyp_init are now passed with a pointer to a struct which means there are scratch registers available for use. Thanks to this, we no longer need to use clever, but hard to read, tricks that avoid the need for scratch registers when checking for the __kvm_hyp_init HVC. Tested-by: David Brazdil Signed-off-by: Andrew Scull Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210125145415.122439-2-ascull@google.com --- arch/arm64/kvm/hyp/nvhe/hyp-init.S | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S index 31b060a44045..b3915ccb23b0 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S +++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S @@ -55,17 +55,10 @@ __do_hyp_init: cmp x0, #HVC_STUB_HCALL_NR b.lo __kvm_handle_stub_hvc - // We only actively check bits [24:31], and everything - // else has to be zero, which we check at build time. -#if (KVM_HOST_SMCCC_FUNC(__kvm_hyp_init) & 0xFFFFFFFF00FFFFFF) -#error Unexpected __KVM_HOST_SMCCC_FUNC___kvm_hyp_init value -#endif + mov x3, #KVM_HOST_SMCCC_FUNC(__kvm_hyp_init) + cmp x0, x3 + b.eq 1f - ror x0, x0, #24 - eor x0, x0, #((KVM_HOST_SMCCC_FUNC(__kvm_hyp_init) >> 24) & 0xF) - ror x0, x0, #4 - eor x0, x0, #((KVM_HOST_SMCCC_FUNC(__kvm_hyp_init) >> 28) & 0xF) - cbz x0, 1f mov x0, #SMCCC_RET_NOT_SUPPORTED eret From 54effa653246c35997f5e990e0134be5be09f9d1 Mon Sep 17 00:00:00 2001 From: Quentin Perret Date: Wed, 3 Feb 2021 14:19:30 +0000 Subject: [PATCH 2/3] asm-generic: export: Stub EXPORT_SYMBOL with __DISABLE_EXPORTS It is currently possible to stub EXPORT_SYMBOL() macros in C code using __DISABLE_EXPORTS, which is necessary to run in constrained environments such as the EFI stub or the decompressor. But this currently doesn't apply to exports from assembly, which can lead to somewhat confusing situations. Consolidate the __DISABLE_EXPORTS infrastructure by checking it from asm-generic/export.h as well. Signed-off-by: Quentin Perret Acked-by: Will Deacon Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210203141931.615898-2-qperret@google.com --- include/asm-generic/export.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h index 365345f9a9e3..07a36a874dca 100644 --- a/include/asm-generic/export.h +++ b/include/asm-generic/export.h @@ -33,7 +33,7 @@ */ .macro ___EXPORT_SYMBOL name,val,sec -#ifdef CONFIG_MODULES +#if defined(CONFIG_MODULES) && !defined(__DISABLE_EXPORTS) .section ___ksymtab\sec+\name,"a" .balign KSYM_ALIGN __ksymtab_\name: From bbc075e01ceac50e0a8353b520544f3089e94e44 Mon Sep 17 00:00:00 2001 From: Quentin Perret Date: Wed, 3 Feb 2021 14:19:31 +0000 Subject: [PATCH 3/3] KVM: arm64: Stub EXPORT_SYMBOL for nVHE EL2 code In order to ensure the module loader does not get confused if a symbol is exported in EL2 nVHE code (as will be the case when we will compile e.g. lib/memset.S into the EL2 object), make sure to stub all exports using __DISABLE_EXPORTS in the nvhe folder. Suggested-by: Ard Biesheuvel Signed-off-by: Quentin Perret Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210203141931.615898-3-qperret@google.com --- arch/arm64/kvm/hyp/nvhe/Makefile | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile index 1f1e351c5fe2..c9c121c8d5de 100644 --- a/arch/arm64/kvm/hyp/nvhe/Makefile +++ b/arch/arm64/kvm/hyp/nvhe/Makefile @@ -3,8 +3,8 @@ # Makefile for Kernel-based Virtual Machine module, HYP/nVHE part # -asflags-y := -D__KVM_NVHE_HYPERVISOR__ -ccflags-y := -D__KVM_NVHE_HYPERVISOR__ +asflags-y := -D__KVM_NVHE_HYPERVISOR__ -D__DISABLE_EXPORTS +ccflags-y := -D__KVM_NVHE_HYPERVISOR__ -D__DISABLE_EXPORTS obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o host.o \ hyp-main.o hyp-smp.o psci-relay.o