On Tue, Jan 15, 2013 at 6:20 AM, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: > Doing arithmetic on the vcpu pointer can be avoided by using > another register as a base. Saves a few instructions on the > switch path. > > Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> > --- > arch/arm/kvm/interrupts_head.S | 32 ++++++++++++++------------------ > 1 file changed, 14 insertions(+), 18 deletions(-) > > diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S > index 0e423be..d2442f9 100644 > --- a/arch/arm/kvm/interrupts_head.S > +++ b/arch/arm/kvm/interrupts_head.S > @@ -264,11 +264,10 @@ vcpu .req r0 @ vcpu pointer always in r0 > str r3, [vcpu, #CP15_OFFSET(c1_CPACR)] > str r4, [vcpu, #CP15_OFFSET(c2_TTBCR)] > str r5, [vcpu, #CP15_OFFSET(c3_DACR)] > - add vcpu, vcpu, #CP15_OFFSET(c2_TTBR0) > - strd r6, r7, [vcpu] > - add vcpu, vcpu, #CP15_OFFSET(c2_TTBR1) - CP15_OFFSET(c2_TTBR0) > - strd r8, r9, [vcpu] > - sub vcpu, vcpu, #CP15_OFFSET(c2_TTBR1) > + add r2, vcpu, #CP15_OFFSET(c2_TTBR0) > + strd r6, r7, [r2] > + add r2, vcpu, #CP15_OFFSET(c2_TTBR1) > + strd r8, r9, [r2] > str r10, [vcpu, #CP15_OFFSET(c10_PRRR)] > str r11, [vcpu, #CP15_OFFSET(c10_NMRR)] > str r12, [vcpu, #CP15_OFFSET(c0_CSSELR)] > @@ -362,11 +361,10 @@ vcpu .req r0 @ vcpu pointer always in r0 > ldr r3, [vcpu, #CP15_OFFSET(c1_CPACR)] > ldr r4, [vcpu, #CP15_OFFSET(c2_TTBCR)] > ldr r5, [vcpu, #CP15_OFFSET(c3_DACR)] > - add vcpu, vcpu, #CP15_OFFSET(c2_TTBR0) > - ldrd r6, r7, [vcpu] > - add vcpu, vcpu, #CP15_OFFSET(c2_TTBR1) - CP15_OFFSET(c2_TTBR0) > - ldrd r8, r9, [vcpu] > - sub vcpu, vcpu, #CP15_OFFSET(c2_TTBR1) > + add r12, vcpu, #CP15_OFFSET(c2_TTBR0) > + ldrd r6, r7, [r12] > + add r12, vcpu, #CP15_OFFSET(c2_TTBR1) > + ldrd r8, r9, [r12] > ldr r10, [vcpu, #CP15_OFFSET(c10_PRRR)] > ldr r11, [vcpu, #CP15_OFFSET(c10_NMRR)] > ldr r12, [vcpu, #CP15_OFFSET(c0_CSSELR)] > @@ -479,7 +477,7 @@ vcpu .req r0 @ vcpu pointer always in r0 > * for the host. > * > * Assumes vcpu pointer in vcpu reg > - * Clobbers r2-r4 > + * Clobbers r2-r5 > */ > .macro save_timer_state > #ifdef CONFIG_KVM_ARM_TIMER > @@ -496,9 +494,8 @@ vcpu .req r0 @ vcpu pointer always in r0 > > mrrc p15, 3, r2, r3, c14 @ CNTV_CVAL > ldr r4, =VCPU_TIMER_CNTV_CVAL > - add vcpu, vcpu, r4 > - strd r2, r3, [vcpu] > - sub vcpu, vcpu, r4 > + add r5, vcpu, r4 > + strd r2, r3, [r5] > > 1: > #endif > @@ -513,7 +510,7 @@ vcpu .req r0 @ vcpu pointer always in r0 > * for the host. > * > * Assumes vcpu pointer in vcpu reg > - * Clobbers r2-r4 > + * Clobbers r2-r5 > */ > .macro restore_timer_state > @ Disallow physical timer access for the guest > @@ -534,9 +531,8 @@ vcpu .req r0 @ vcpu pointer always in r0 > mcrr p15, 4, r2, r3, c14 @ CNTVOFF > > ldr r4, =VCPU_TIMER_CNTV_CVAL > - add vcpu, vcpu, r4 > - ldrd r2, r3, [vcpu] > - sub vcpu, vcpu, r4 > + add r5, vcpu, r4 > + ldrd r2, r3, [r5] > mcrr p15, 3, r2, r3, c14 @ CNTV_CVAL > isb > > -- > 1.8.1 > much nicer, thanks. -Christoffer _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
