| Message ID | 1358248829-13764-1-git-send-email-marc.zyngier@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Jan 15, 2013 at 6:20 AM, Marc Zyngier <marc.zyngier@arm.com> 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@arm.com> > --- > 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
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
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@arm.com> --- arch/arm/kvm/interrupts_head.S | 32 ++++++++++++++------------------ 1 file changed, 14 insertions(+), 18 deletions(-)