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has_vhe() expands to a compile-time constant when evaluated from the VHE or nVHE code, alternatively checking a static key when called from elsewhere in the kernel. On face value, this looks like a case of premature optimization, but in fact this allows symbol references on VHE-specific code paths to be dropped from the nVHE object. Expand the comment in has_vhe() to make this clearer, hopefully discouraging anybody from simplifying the code. Cc: David Brazdil <dbrazdil@google.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220609121223.2551-5-will@kernel.org
143 lines
3.8 KiB
C
143 lines
3.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2012 ARM Ltd.
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* Author: Marc Zyngier <marc.zyngier@arm.com>
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*/
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#ifndef __ASM__VIRT_H
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#define __ASM__VIRT_H
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/*
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* The arm64 hcall implementation uses x0 to specify the hcall
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* number. A value less than HVC_STUB_HCALL_NR indicates a special
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* hcall, such as set vector. Any other value is handled in a
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* hypervisor specific way.
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*
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* The hypercall is allowed to clobber any of the caller-saved
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* registers (x0-x18), so it is advisable to use it through the
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* indirection of a function call (as implemented in hyp-stub.S).
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*/
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/*
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* HVC_SET_VECTORS - Set the value of the vbar_el2 register.
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*
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* @x1: Physical address of the new vector table.
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*/
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#define HVC_SET_VECTORS 0
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/*
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* HVC_SOFT_RESTART - CPU soft reset, used by the cpu_soft_restart routine.
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*/
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#define HVC_SOFT_RESTART 1
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/*
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* HVC_RESET_VECTORS - Restore the vectors to the original HYP stubs
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*/
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#define HVC_RESET_VECTORS 2
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/*
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* HVC_VHE_RESTART - Upgrade the CPU from EL1 to EL2, if possible
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*/
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#define HVC_VHE_RESTART 3
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/* Max number of HYP stub hypercalls */
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#define HVC_STUB_HCALL_NR 4
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/* Error returned when an invalid stub number is passed into x0 */
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#define HVC_STUB_ERR 0xbadca11
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#define BOOT_CPU_MODE_EL1 (0xe11)
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#define BOOT_CPU_MODE_EL2 (0xe12)
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#ifndef __ASSEMBLY__
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#include <asm/ptrace.h>
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#include <asm/sections.h>
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#include <asm/sysreg.h>
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#include <asm/cpufeature.h>
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/*
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* __boot_cpu_mode records what mode CPUs were booted in.
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* A correctly-implemented bootloader must start all CPUs in the same mode:
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* In this case, both 32bit halves of __boot_cpu_mode will contain the
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* same value (either 0 if booted in EL1, BOOT_CPU_MODE_EL2 if booted in EL2).
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*
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* Should the bootloader fail to do this, the two values will be different.
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* This allows the kernel to flag an error when the secondaries have come up.
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*/
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extern u32 __boot_cpu_mode[2];
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#define ARM64_VECTOR_TABLE_LEN SZ_2K
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void __hyp_set_vectors(phys_addr_t phys_vector_base);
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void __hyp_reset_vectors(void);
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DECLARE_STATIC_KEY_FALSE(kvm_protected_mode_initialized);
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/* Reports the availability of HYP mode */
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static inline bool is_hyp_mode_available(void)
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{
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/*
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* If KVM protected mode is initialized, all CPUs must have been booted
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* in EL2. Avoid checking __boot_cpu_mode as CPUs now come up in EL1.
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*/
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if (IS_ENABLED(CONFIG_KVM) &&
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static_branch_likely(&kvm_protected_mode_initialized))
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return true;
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return (__boot_cpu_mode[0] == BOOT_CPU_MODE_EL2 &&
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__boot_cpu_mode[1] == BOOT_CPU_MODE_EL2);
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}
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/* Check if the bootloader has booted CPUs in different modes */
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static inline bool is_hyp_mode_mismatched(void)
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{
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/*
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* If KVM protected mode is initialized, all CPUs must have been booted
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* in EL2. Avoid checking __boot_cpu_mode as CPUs now come up in EL1.
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*/
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if (IS_ENABLED(CONFIG_KVM) &&
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static_branch_likely(&kvm_protected_mode_initialized))
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return false;
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return __boot_cpu_mode[0] != __boot_cpu_mode[1];
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}
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static inline bool is_kernel_in_hyp_mode(void)
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{
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return read_sysreg(CurrentEL) == CurrentEL_EL2;
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}
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static __always_inline bool has_vhe(void)
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{
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/*
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* Code only run in VHE/NVHE hyp context can assume VHE is present or
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* absent. Otherwise fall back to caps.
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* This allows the compiler to discard VHE-specific code from the
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* nVHE object, reducing the number of external symbol references
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* needed to link.
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*/
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if (is_vhe_hyp_code())
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return true;
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else if (is_nvhe_hyp_code())
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return false;
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else
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return cpus_have_final_cap(ARM64_HAS_VIRT_HOST_EXTN);
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}
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static __always_inline bool is_protected_kvm_enabled(void)
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{
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if (is_vhe_hyp_code())
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return false;
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else
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return cpus_have_final_cap(ARM64_KVM_PROTECTED_MODE);
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}
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static inline bool is_hyp_nvhe(void)
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{
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return is_hyp_mode_available() && !is_kernel_in_hyp_mode();
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}
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#endif /* __ASSEMBLY__ */
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#endif /* ! __ASM__VIRT_H */
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