Messages in this thread | | | Date | Thu, 18 Jun 2020 14:57:45 +0100 | From | Marc Zyngier <> | Subject | Re: [PATCH v3 02/15] arm64: kvm: Move __smccc_workaround_1_smc to .rodata |
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Hi David,
On 2020-06-18 13:25, David Brazdil wrote: > This snippet of assembly is used by cpu_errata.c to overwrite parts of > KVM hyp > vector. Move it to its own source file and change its ELF section to > .rodata. > > Signed-off-by: David Brazdil <dbrazdil@google.com> > --- > arch/arm64/kvm/hyp/Makefile | 1 + > arch/arm64/kvm/hyp/hyp-entry.S | 16 ---------------- > arch/arm64/kvm/hyp/smccc_wa.S | 30 ++++++++++++++++++++++++++++++ > 3 files changed, 31 insertions(+), 16 deletions(-) > create mode 100644 arch/arm64/kvm/hyp/smccc_wa.S > > diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile > index 8c9880783839..5d8357ddc234 100644 > --- a/arch/arm64/kvm/hyp/Makefile > +++ b/arch/arm64/kvm/hyp/Makefile > @@ -7,6 +7,7 @@ ccflags-y += -fno-stack-protector > -DDISABLE_BRANCH_PROFILING \ > $(DISABLE_STACKLEAK_PLUGIN) > > obj-$(CONFIG_KVM) += hyp.o > +obj-$(CONFIG_KVM_INDIRECT_VECTORS) += smccc_wa.o > > hyp-y := vgic-v3-sr.o timer-sr.o aarch32.o vgic-v2-cpuif-proxy.o > sysreg-sr.o \ > debug-sr.o entry.o switch.o fpsimd.o tlb.o hyp-entry.o > diff --git a/arch/arm64/kvm/hyp/hyp-entry.S > b/arch/arm64/kvm/hyp/hyp-entry.S > index 9c5cfb04170e..d362fad97cc8 100644 > --- a/arch/arm64/kvm/hyp/hyp-entry.S > +++ b/arch/arm64/kvm/hyp/hyp-entry.S > @@ -318,20 +318,4 @@ SYM_CODE_START(__bp_harden_hyp_vecs) > 1: .org __bp_harden_hyp_vecs + __BP_HARDEN_HYP_VECS_SZ > .org 1b > SYM_CODE_END(__bp_harden_hyp_vecs) > - > - .popsection
I'd be tempted to leave the .popsection in place, if only for symmetry with the initial .pushsection.
> - > -SYM_CODE_START(__smccc_workaround_1_smc) > - esb > - sub sp, sp, #(8 * 4) > - stp x2, x3, [sp, #(8 * 0)] > - stp x0, x1, [sp, #(8 * 2)] > - mov w0, #ARM_SMCCC_ARCH_WORKAROUND_1 > - smc #0 > - ldp x2, x3, [sp, #(8 * 0)] > - ldp x0, x1, [sp, #(8 * 2)] > - add sp, sp, #(8 * 4) > -1: .org __smccc_workaround_1_smc + __SMCCC_WORKAROUND_1_SMC_SZ > - .org 1b > -SYM_CODE_END(__smccc_workaround_1_smc) > #endif > diff --git a/arch/arm64/kvm/hyp/smccc_wa.S > b/arch/arm64/kvm/hyp/smccc_wa.S > new file mode 100644 > index 000000000000..aa25b5428e77 > --- /dev/null > +++ b/arch/arm64/kvm/hyp/smccc_wa.S > @@ -0,0 +1,30 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright (C) 2015-2018 - ARM Ltd > + * Author: Marc Zyngier <marc.zyngier@arm.com> > + */ > + > +#include <linux/arm-smccc.h> > + > +#include <asm/kvm_asm.h> > +#include <asm/kvm_mmu.h> > + > + /* > + * This is not executed directly and is instead copied into the > vectors > + * by install_bp_hardening_cb(). > + */ > + .data > + .pushsection .rodata > + .global __smccc_workaround_1_smc > +__smccc_workaround_1_smc:
You probably want to replace this with SYM_DATA_START (and SYM_DATA_END at the end).
> + esb > + sub sp, sp, #(8 * 4) > + stp x2, x3, [sp, #(8 * 0)] > + stp x0, x1, [sp, #(8 * 2)] > + mov w0, #ARM_SMCCC_ARCH_WORKAROUND_1 > + smc #0 > + ldp x2, x3, [sp, #(8 * 0)] > + ldp x0, x1, [sp, #(8 * 2)] > + add sp, sp, #(8 * 4) > +1: .org __smccc_workaround_1_smc + __SMCCC_WORKAROUND_1_SMC_SZ > + .org 1b
Otherwise, looks good.
Thanks,
M. -- Jazz is not dead. It just smells funny...
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