From e078ef81514222ffc10bf1767c15df16ca0b84db Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 14 Dec 2015 17:58:33 +0000 Subject: [PATCH] ARM: KVM: Cleanup exception injection David Binderman reported that the exception injection code had a couple of unused variables lingering around. Upon examination, it looked like this code could do with an anticipated spring cleaning, which amounts to deduplicating the CPSR/SPSR update, and making it look a bit more like the architecture spec. The spurious variables are removed in the process. Reported-by: David Binderman Reviewed-by: Christoffer Dall Signed-off-by: Marc Zyngier --- arch/arm/kvm/emulate.c | 74 ++++++++++++++++++++++-------------------- 1 file changed, 38 insertions(+), 36 deletions(-) diff --git a/arch/arm/kvm/emulate.c b/arch/arm/kvm/emulate.c index d6c005283678..dc99159857b4 100644 --- a/arch/arm/kvm/emulate.c +++ b/arch/arm/kvm/emulate.c @@ -275,6 +275,40 @@ static u32 exc_vector_base(struct kvm_vcpu *vcpu) return vbar; } +/* + * Switch to an exception mode, updating both CPSR and SPSR. Follow + * the logic described in AArch32.EnterMode() from the ARMv8 ARM. + */ +static void kvm_update_psr(struct kvm_vcpu *vcpu, unsigned long mode) +{ + unsigned long cpsr = *vcpu_cpsr(vcpu); + u32 sctlr = vcpu->arch.cp15[c1_SCTLR]; + + *vcpu_cpsr(vcpu) = (cpsr & ~MODE_MASK) | mode; + + switch (mode) { + case FIQ_MODE: + *vcpu_cpsr(vcpu) |= PSR_F_BIT; + /* Fall through */ + case ABT_MODE: + case IRQ_MODE: + *vcpu_cpsr(vcpu) |= PSR_A_BIT; + /* Fall through */ + default: + *vcpu_cpsr(vcpu) |= PSR_I_BIT; + } + + *vcpu_cpsr(vcpu) &= ~(PSR_IT_MASK | PSR_J_BIT | PSR_E_BIT | PSR_T_BIT); + + if (sctlr & SCTLR_TE) + *vcpu_cpsr(vcpu) |= PSR_T_BIT; + if (sctlr & SCTLR_EE) + *vcpu_cpsr(vcpu) |= PSR_E_BIT; + + /* Note: These now point to the mode banked copies */ + *vcpu_spsr(vcpu) = cpsr; +} + /** * kvm_inject_undefined - inject an undefined exception into the guest * @vcpu: The VCPU to receive the undefined exception @@ -286,29 +320,13 @@ static u32 exc_vector_base(struct kvm_vcpu *vcpu) */ void kvm_inject_undefined(struct kvm_vcpu *vcpu) { - unsigned long new_lr_value; - unsigned long new_spsr_value; unsigned long cpsr = *vcpu_cpsr(vcpu); - u32 sctlr = vcpu->arch.cp15[c1_SCTLR]; bool is_thumb = (cpsr & PSR_T_BIT); u32 vect_offset = 4; u32 return_offset = (is_thumb) ? 2 : 4; - new_spsr_value = cpsr; - new_lr_value = *vcpu_pc(vcpu) - return_offset; - - *vcpu_cpsr(vcpu) = (cpsr & ~MODE_MASK) | UND_MODE; - *vcpu_cpsr(vcpu) |= PSR_I_BIT; - *vcpu_cpsr(vcpu) &= ~(PSR_IT_MASK | PSR_J_BIT | PSR_E_BIT | PSR_T_BIT); - - if (sctlr & SCTLR_TE) - *vcpu_cpsr(vcpu) |= PSR_T_BIT; - if (sctlr & SCTLR_EE) - *vcpu_cpsr(vcpu) |= PSR_E_BIT; - - /* Note: These now point to UND banked copies */ - *vcpu_spsr(vcpu) = cpsr; - *vcpu_reg(vcpu, 14) = new_lr_value; + kvm_update_psr(vcpu, UND_MODE); + *vcpu_reg(vcpu, 14) = *vcpu_pc(vcpu) - return_offset; /* Branch to exception vector */ *vcpu_pc(vcpu) = exc_vector_base(vcpu) + vect_offset; @@ -320,30 +338,14 @@ void kvm_inject_undefined(struct kvm_vcpu *vcpu) */ static void inject_abt(struct kvm_vcpu *vcpu, bool is_pabt, unsigned long addr) { - unsigned long new_lr_value; - unsigned long new_spsr_value; unsigned long cpsr = *vcpu_cpsr(vcpu); - u32 sctlr = vcpu->arch.cp15[c1_SCTLR]; bool is_thumb = (cpsr & PSR_T_BIT); u32 vect_offset; u32 return_offset = (is_thumb) ? 4 : 0; bool is_lpae; - new_spsr_value = cpsr; - new_lr_value = *vcpu_pc(vcpu) + return_offset; - - *vcpu_cpsr(vcpu) = (cpsr & ~MODE_MASK) | ABT_MODE; - *vcpu_cpsr(vcpu) |= PSR_I_BIT | PSR_A_BIT; - *vcpu_cpsr(vcpu) &= ~(PSR_IT_MASK | PSR_J_BIT | PSR_E_BIT | PSR_T_BIT); - - if (sctlr & SCTLR_TE) - *vcpu_cpsr(vcpu) |= PSR_T_BIT; - if (sctlr & SCTLR_EE) - *vcpu_cpsr(vcpu) |= PSR_E_BIT; - - /* Note: These now point to ABT banked copies */ - *vcpu_spsr(vcpu) = cpsr; - *vcpu_reg(vcpu, 14) = new_lr_value; + kvm_update_psr(vcpu, ABT_MODE); + *vcpu_reg(vcpu, 14) = *vcpu_pc(vcpu) + return_offset; if (is_pabt) vect_offset = 12;